Docs

Samples

Table Of Contents

• Samples
• Rendering Basics
• Labels - main.rb
• Labels Text Wrapping - main.rb
• Lines - main.rb
• Solids Borders - main.rb
• Sprites - main.rb
• Sounds - main.rb
• Input Basics
• Keyboard - main.rb
• Moving A Sprite - main.rb
• Mouse - main.rb
• Mouse Properties - main.rb
• Mouse Point To Rect - main.rb
• Mouse Drag And Drop - main.rb
• Mouse Rect To Rect - main.rb
• Controller - main.rb
• Touch - main.rb
• Managing Scenes - main.rb
• Rendering Sprites
• Animation Using Separate Pngs - main.rb
• Animation Using Sprite Sheet - main.rb
• Animation States 1 - main.rb
• Animation States 2 - main.rb
• Animation States 3 - main.rb
• Color And Rotation - main.rb
• Particles - main.rb
• Physics And Collisions
• Simple - main.rb
• Simple Aabb Collision - main.rb
• Simple Aabb Collision With Map Editor - main.rb
• Simple Aabb Collision With Map Editor - Data - terrain.txt
• Moving Objects - main.rb
• Entities - main.rb
• Box Collision - main.rb
• Box Collision 2 - main.rb
• Box Collision 3 - main.rb
• Jump Physics - main.rb
• Bouncing On Collision - ball.rb
• Bouncing On Collision - block.rb
• Bouncing On Collision - cannon.rb
• Bouncing On Collision - main.rb
• Bouncing On Collision - peg.rb
• Bouncing On Collision - vector2d.rb
• Arbitrary Collision - ball.rb
• Arbitrary Collision - blocks.rb
• Arbitrary Collision - linear_collider.rb
• Arbitrary Collision - main.rb
• Arbitrary Collision - paddle.rb
• Arbitrary Collision - rectangle.rb
• Arbitrary Collision - square_collider.rb
• Arbitrary Collision - vector2d.rb
• Collision With Object Removal - ball.rb
• Collision With Object Removal - linear_collider.rb
• Collision With Object Removal - main.rb
• Collision With Object Removal - paddle.rb
• Collision With Object Removal - tests.rb
• Collision With Object Removal - vector2d.rb
• Bouncing Ball With Gravity - main.rb
• Ramp Collision - main.rb
• Verlet Integration - main.rb
• Mouse
• Mouse Click - main.rb
• Mouse Move - main.rb
• Mouse Move Paint App - main.rb
• Coordinate Systems - main.rb
• Clicking Buttons - main.rb
• Save Load
• Save Load Game - main.rb
• Advanced Audio
• Audio Mixer - main.rb
• Audio Mixer - server_ip_address.txt
• Sound Synthesis - main.rb
• Rhythm Game Calibration - main.rb
• Advanced Rendering
• Render Targets Clip Area - main.rb
• Render Targets Combining Sprites - main.rb
• Simple Render Targets - main.rb
• Coordinate Systems And Render Targets - main.rb
• Render Targets Repeating Texture - main.rb
• Render Targets Thick Lines - main.rb
• Render Targets With Tile Manipulation - main.rb
• Render Target Viewports - main.rb
• Render Primitive Hierarchies - main.rb
• Render Primitives As Hash - main.rb
• Buttons As Render Targets - main.rb
• Pixel Arrays - main.rb
• Pixel Arrays From File - main.rb
• Shake Camera - main.rb
• Simple Camera - main.rb
• Simple Camera Multiple Targets - main.rb
• Splitscreen Camera - main.rb
• Z Targeting Camera - main.rb
• Camera And Large Map - main.rb
• Camera And Large Sprites - main.rb
• Blend Modes - main.rb
• Blend Modes Additive Modulo - main.rb
• Render Target Noclear - main.rb
• Lighting - main.rb
• Triangles - main.rb
• Triangles Trapezoid - main.rb
• Camera Space World Space Simple - main.rb
• Camera Space World Space Simple Grid Map - main.rb
• Matrix And Triangles 2d - main.rb
• Matrix And Triangles 3d - main.rb
• Matrix Camera Space World Space - main.rb
• Matrix Cubeworld - main.rb
• Matrix Cubeworld - modeling-api.rb
• Override Core Rendering - main.rb
• Layouts - main.rb
• 19 Layouts Extended Parameters - main.rb
• Advanced Rendering Hd
• Hd Labels - main.rb
• Texture Atlases - main.rb
• Allscreen Properties - main.rb
• Layouts And Portrait Mode - main.rb
• Tweening Lerping Easing Functions
• Easing Functions - main.rb
• Cubic Bezier - main.rb
• Easing Using Spline - main.rb
• Pulsing Button - main.rb
• Scene Transitions - main.rb
• Animation Queues - main.rb
• Animation Queues Advanced - main.rb
• Cutscenes - main.rb
• Performance
• Sprites As Hash - main.rb
• Sprites As Entities - main.rb
• Sprites As Strict Entities - main.rb
• Sprites As Classes - main.rb
• Static Sprites As Classes - main.rb
• Static Sprites As Classes With Custom Drawing - main.rb
• Collision Limits - main.rb
• Collision Limits Aabb - main.rb
• Collision Limits Find Single - main.rb
• Collision Limits Many To Many - main.rb
• Ui Controls
• Checkboxes - main.rb
• Menu Navigation - main.rb
• Radial Menu - main.rb
• Scroll View - main.rb
• Accessiblity For The Blind - main.rb
• Advanced Debugging
• Unit Tests - main.rb
• Unit Tests - benchmark_api_tests.rb
• Unit Tests - enumerable_class_function_tests.rb
• Unit Tests - exception_raising_tests.rb
• Unit Tests - fn_tests.rb
• Unit Tests - gen_docs.rb
• Unit Tests - geometry_tests.rb
• Unit Tests - http_tests.rb
• Unit Tests - input_emulation_tests.rb
• Unit Tests - nil_coercion_tests.rb
• Unit Tests - object_to_primitive_tests.rb
• Unit Tests - parsing_tests.rb
• Unit Tests - pretty_format_tests.rb
• Unit Tests - require_tests.rb
• Unit Tests - serialize_deserialize_tests.rb
• Unit Tests - state_serialization_experimental_tests.rb
• Unit Tests - suggest_autocompletion_tests.rb
• Http
• Retrieve Images - main.rb
• In Game Web Server Http Get - main.rb
• In Game Web Server Http Get - Metadata - cvars.txt
• In Game Web Server Http Post - main.rb
• In Game Web Server Http Post - Metadata - cvars.txt
• C Extensions
• Basics - main.rb
• Intermediate - main.rb
• Native Pixel Arrays - main.rb
• Handcrafted Extension - main.rb
• Handcrafted Extension - license.txt
• Handcrafted Extension Advanced - main.rb
• Handcrafted Extension Advanced - license.txt
• Handcrafted Extension Advanced - Metadata - cvars.txt
• Ios main.rb
• Ios Metadata - cvars.txt
• Ios Metadata - ios_metadata.txt
• Handcrafted Mac Extension - main.rb
• Handcrafted Mac Extension - readme.txt
• Handcrafted Steam Extensions-native - Steam - download.txt
• Handcrafted Steam Extensions-native - steam_appid.txt
• Handcrafted Steam Extensions - main.rb
• Handcrafted Steam Extensions - readme.txt
• Path Finding Algorithms
• Breadth First Search - main.rb
• Detailed Breadth First Search - main.rb
• Breadcrumbs - main.rb
• Early Exit - main.rb
• Dijkstra - main.rb
• Heuristic - main.rb
• Heuristic With Walls - main.rb
• A Star - main.rb
• Tower Defense - main.rb
• Moveable Squares - main.rb
• Vr
• Skybox - main.rb
• Skybox - tick.rb
• Top Down Rpg - main.rb
• Top Down Rpg - tick.rb
• Space Invaders - main.rb
• Space Invaders - tick.rb
• Let There Be Light - main.rb
• Let There Be Light - tick.rb
• Draw A Cube - main.rb
• Draw A Cube - tick.rb
• Draw A Cube With Triangles - main.rb
• Draw A Cube With Triangles - tick.rb
• Gimbal Lock - main.rb
• Gimbal Lock - tick.rb
• Citadels - main.rb
• Citadels - tick.rb
• Flappy credits.txt
• Flappy main.rb
• Flappy tick.rb
• Cubeworld main.rb
• Cubeworld tick.rb
• Genre 3d
• 3d Cube - main.rb
• Wireframe - main.rb
• Wireframe - Data - what-is-this.txt
• Yaw Pitch Roll - main.rb
• Ray Caster - main.rb
• Ray Caster Advanced - main.rb
• Genre Arcade
• Bullet Heaven - main.rb
• Bullet Hell - main.rb
• Dueling Starships - main.rb
• arcade/flappy dragon/credits.txt
• arcade/flappy dragon/main.rb
• Pong - main.rb
• Snakemoji - main.rb
• Solar System - main.rb
• Sound Golf - main.rb
• Squares - main.rb
• Twinstick - main.rb
• Genre Board Game
• Fifteen Puzzle - main.rb
• Genre Boss Battle
• Boss Battle Game Jam - main.rb
• Genre Crafting
• Alchemy Game Starting Point - main.rb
• Craft Game Starting Point - main.rb
• Farming Game Starting Point - main.rb
• Genre Dev Tools
• Add Buttons To Console - main.rb
• Animation Creator Starting Point - main.rb
• Frame By Frame - main.rb
• Tile Editor Starting Point - main.rb
• Genre Dungeon Crawl
• Classics Jam - main.rb
• Genre Fighting
• Special Move Inputs - main.rb
• Genre Lowrez
• Nokia 3310 - main.rb
• Nokia 3310 - nokia.rb
• Resolution 64x64 - lowrez.rb
• Resolution 64x64 - main.rb
• Genre Mario
• Jumping - main.rb
• Jumping And Collisions - main.rb
• Genre Platformer
• Clepto Frog - main.rb
• Clepto Frog - Data - mugs.txt
• Clepto Frog - Data - walls.txt
• Gorillas Basic - credits.txt
• Gorillas Basic - main.rb
• Map Editor - camera.rb
• Map Editor - level_editor.rb
• Map Editor - main.rb
• Map Editor - root_scene.rb
• Map Editor - Data - terrain.txt
• Shadows - main.rb
• The Little Probe - main.rb
• The Little Probe - Data - level.txt
• The Little Probe - Data - level_lava.txt
• Genre Rpg Narrative
• Choose Your Own Adventure - decision.rb
• Choose Your Own Adventure - main.rb
• Return Of Serenity - lowrez_simulator.rb
• Return Of Serenity - main.rb
• Return Of Serenity - require.rb
• Return Of Serenity - storyline.rb
• Return Of Serenity - storyline_anka.rb
• Return Of Serenity - storyline_blinking_light.rb
• Return Of Serenity - storyline_day_one.rb
• Return Of Serenity - storyline_final_decision.rb
• Return Of Serenity - storyline_final_message.rb
• Return Of Serenity - storyline_serenity_alive.rb
• Return Of Serenity - storyline_serenity_bio.rb
• Return Of Serenity - storyline_serenity_introduction.rb
• Return Of Serenity - storyline_speed_of_light.rb
• Genre Rpg Roguelike
• Roguelike Starting Point - constants.rb
• Roguelike Starting Point - legend.rb
• Roguelike Starting Point - main.rb
• Roguelike Starting Point - sprite_lookup.rb
• Roguelike Line Of Sight - main.rb
• Genre Rpg Tactical
• Hexagonal Grid - main.rb
• Isometric Grid - main.rb
• Genre Rpg Topdown
• Topdown Casino - main.rb
• Topdown Starting Point - main.rb
• Genre Rpg Turn Based
• Turn Based Battle - main.rb
• Genre Simulation
• Sand main.rb
• Genre Twenty Second Games
• Twenty Second Starting Point - main.rb

Samples link

Follows is a source code listing for all files that have been open sourced. This code can be found in the ./samples directory.

Rendering Basics link

Labels - main.rb link

# ./samples/01_rendering_basics/01_labels/app/main.rb
=begin

APIs listing that haven't been encountered in a previous sample apps:

- args.outputs.labels: An array. Values in this array generate labels the screen.

=end

# Labels are used to represent text elements in DragonRuby

# An example of creating a label is:
# args.outputs.labels << [320, 640, "Example", 3, 1, 255, 0, 0, 200, manaspace.ttf]

# The code above does the following:
# 1. GET the place where labels go: args.outputs.labels
# 2. Request a new LABEL be ADDED: <<
# 3. The DEFINITION of a LABEL is the ARRAY:
#     [320, 640, "Example
#     [ X ,  Y,    TEXT]
# 4. It's recommended to use hashes so that you're not reliant on positional values:
#    { x: 320,
#      y: 640,
#      text: "Text",
#      font: "fonts/font.ttf",
#      anchor_x: 0.5, # or alignment_enum: 0, 1, or 2
#      anchor_y: 0.5, # or vertical_alignment_enum: 0, 1, or 2
#      r: 0,
#      g: 0,
#      b: 0,
#      a: 255,
#      size_px: 20,   # or size_enum: -10 to 10 (0 means "ledgible on small devices" ie: 20px)
#      blendmode_enum: 1 }


# The tick method is called by DragonRuby every frame
# args contains all the information regarding the game.
def tick args
  # render the current frame to the screen using a simple array
  # this is useful for quick and dirty output and is recommended to use
  # a Hash to render long term.
  args.outputs.labels << [640, 650, "frame: #{Kernel.tick_count}"]

  # render the current frame to the screen centered vertically and horizontally at 640, 620
  args.outputs.labels << { x: 640, y: 620, anchor_x: 0.5, anchor_y: 0.5, text: "frame: #{Kernel.tick_count}" }

  # Here are some examples of simple labels, with the minimum number of parameters
  # Note that the default values for the other parameters are 0, except for Alpha which is 255 and Font Style which is the default font
  args.outputs.labels << { x: 5,          y: 720 - 5, text: "This is a label located at the top left." }
  args.outputs.labels << { x: 5,          y:      30, text: "This is a label located at the bottom left." }
  args.outputs.labels << { x: 1280 - 420, y: 720 - 5, text: "This is a label located at the top right." }
  args.outputs.labels << { x: 1280 - 440, y: 30,      text: "This is a label located at the bottom right." }

  # Demonstration of the Size Enum Parameter

  # size_enum of -2 is equivalent to using size_px: 18
  args.outputs.labels << { x: 175 + 150, y: 635 - 50, text: "Smaller label.",  size_enum: -2 }
  args.outputs.labels << { x: 175 + 150, y: 620 - 50, text: "Smaller label.",  size_px: 18 }

  # size_enum of -1 is equivalent to using size_px: 20
  args.outputs.labels << { x: 175 + 150, y: 595 - 50, text: "Small label.",    size_enum: -1 }
  args.outputs.labels << { x: 175 + 150, y: 580 - 50, text: "Small label.",    size_px: 20 }

  # size_enum of  0 is equivalent to using size_px: 22
  args.outputs.labels << { x: 175 + 150, y: 550 - 50, text: "Medium label.",   size_enum:  0 }

  # size_enum of  0 is equivalent to using size_px: 24
  args.outputs.labels << { x: 175 + 150, y: 520 - 50, text: "Large label.",    size_enum:  1 }

  # size_enum of  0 is equivalent to using size_px: 26
  args.outputs.labels << { x: 175 + 150, y: 490 - 50, text: "Larger label.",   size_enum:  2 }

  # Demonstration of the Align Parameter
  args.outputs.lines  << { x: 175 + 150, y: 0, h: 720 }

  # alignment_enum: 0 is equivalent to anchor_x: 0
  # vertical_alignment_enum: 1 is equivalent to anchor_y: 0.5
  args.outputs.labels << { x: 175 + 150, y: 360 - 50, text: "Left aligned.",   alignment_enum: 0, vertical_alignment_enum: 1 }
  args.outputs.labels << { x: 175 + 150, y: 342 - 50, text: "Left aligned.",   anchor_x: 0, anchor_y: 0.5 }

  # alignment_enum: 1 is equivalent to anchor_x: 0.5
  args.outputs.labels << { x: 175 + 150, y: 325 - 50, text: "Center aligned.", alignment_enum: 1, vertical_alignment_enum: 1  }

  # alignment_enum: 2 is equivalent to anchor_x: 1
  args.outputs.labels << { x: 175 + 150, y: 305 - 50, text: "Right aligned.",  alignment_enum: 2 }

  # Demonstration of the RGBA parameters
  args.outputs.labels << { x: 600  + 150, y: 590 - 50, text: "Red Label.",   r: 255, g:   0, b:   0 }
  args.outputs.labels << { x: 600  + 150, y: 570 - 50, text: "Green Label.", r:   0, g: 255, b:   0 }
  args.outputs.labels << { x: 600  + 150, y: 550 - 50, text: "Blue Label.",  r:   0, g:   0, b: 255 }
  args.outputs.labels << { x: 600  + 150, y: 530 - 50, text: "Faded Label.", r:   0, g:   0, b:   0, a: 128 }

  # providing a custom font
  args.outputs.labels << { x: 690 + 150,
                           y: 330 - 50,
                           text: "Custom font (Hash)",
                           size_enum: 0,                 # equivalent to size_px:  22
                           alignment_enum: 1,            # equivalent to anchor_x: 0.5
                           vertical_alignment_enum: 2,   # equivalent to anchor_y: 1
                           r: 125,
                           g: 0,
                           b: 200,
                           a: 255,
                           font: "manaspc.ttf" }

  # Primitives can hold anything, and can be given a label in the following forms
  args.outputs.primitives << { x: 690 + 150,
                               y: 330 - 80,
                               text: "Custom font (.primitives Hash)",
                               size_enum: 0,
                               alignment_enum: 1,
                               r: 125,
                               g: 0,
                               b: 200,
                               a: 255,
                               font: "manaspc.ttf" }

  args.outputs.labels << { x: 640,
                           y: 100,
                           anchor_x: 0.5,
                           anchor_y: 0.5,
                           text: "Ніколи не здам тебе. Ніколи не підведу тебе. Ніколи не буду бігати навколо і залишати тебе." }
end

Labels Text Wrapping - main.rb link

# ./samples/01_rendering_basics/01_labels_text_wrapping/app/main.rb
def tick args
  # create a really long string
  really_long_string =  "Lorem ipsum dolor sit amet, consectetur adipiscing elit. In vulputate viverra metus et vehicula. Aenean quis accumsan dolor. Nulla tempus, ex et lacinia elementum, nisi felis ullamcorper sapien, sed sagittis sem justo eu lectus. Etiam ut vehicula lorem, nec placerat ligula. Duis varius ultrices magna non sagittis. Aliquam et sem vel risus viverra hendrerit. Maecenas dapibus congue lorem, a blandit mauris feugiat sit amet."
  really_long_string += "\n\n"
  really_long_string += "Sed quis metus lacinia mi dapibus fermentum nec id nunc. Donec tincidunt ante a sem bibendum, eget ultricies ex mollis. Quisque venenatis erat quis pretium bibendum. Pellentesque vel laoreet nibh. Cras gravida nisi nec elit pulvinar, in feugiat leo blandit. Quisque sodales quam sed congue consequat. Vivamus placerat risus vitae ex feugiat viverra. In lectus arcu, pellentesque vel ipsum ac, dictum finibus enim. Quisque consequat leo in urna dignissim, eu tristique ipsum accumsan. In eros sem, iaculis ac rhoncus eu, laoreet vitae ipsum. In sodales, ante eu tempus vehicula, mi nulla luctus turpis, eu egestas leo sapien et mi."

  # length of characters on line
  max_character_length = 80

  # API: String.wrapped_lines(string, max_character_length)
  long_strings_split = String.wrapped_lines really_long_string,
                                            max_character_length

  # render a label for each line and offset by the index value
  # setting the anchor_y for a label will offset the text by its
  # height
  args.outputs.labels << long_strings_split.map_with_index do |s, i|
    {
      x: 60,
      y: 720 - 60,
      anchor_y: i,
      text: s
    }
  end
end

Lines - main.rb link

# ./samples/01_rendering_basics/02_lines/app/main.rb
=begin
APIs listing that haven't been encountered in a previous sample apps:

- args.outputs.lines: Provided an Array or a Hash, lines will be rendered to the screen.
- Kernel.tick_count: This property contains an integer value that
  represents the current frame. DragonRuby renders at 60 FPS. A value of 0
  for Kernel.tick_count represents the initial load of the game.
=end

# The parameters required for lines are:
# 1. The initial point (x, y)
# 2. The end point (x2, y2)
# 3. The rgba values for the color and transparency (r, g, b, a)
#    Creating a line using an Array (quick and dirty):
#    [x, y, x2, y2, r, g, b, a]
#    args.outputs.lines << [100, 100, 300, 300, 255, 0, 255, 255]
#    This would create a line from (100, 100) to (300, 300)
#    The RGB code (255, 0, 255) would determine its color, a purple
#    It would have an Alpha value of 255, making it completely opaque
# 4. Using Hashes, the keys are :x, :y, :x2, :y2, :r, :g, :b, and :a
def tick args
  args.outputs.labels << { x: 640,
                           y: 700,
                           text: "Sample app shows how to create lines.",
                           size_px: 22,
                           anchor_x: 0.5,
                           anchor_y: 0.5 }

  # Render lines using Arrays/Tuples
  # This is quick and dirty and it's recommended to use Hashes long term
  args.outputs.lines  << [380, 450, 675, 450]
  args.outputs.lines  << [380, 410, 875, 410]

  # These examples utilize Kernel.tick_count to change the length of the lines over time
  # Kernel.tick_count is the ticks that have occurred in the game
  # This is accomplished by making either the starting or ending point based on the Kernel.tick_count
  args.outputs.lines  << { x:  380,
                           y:  370,
                           x2: 875,
                           y2: 370,
                           r:  Kernel.tick_count % 255,
                           g:  0,
                           b:  0,
                           a:  255 }

  args.outputs.lines  << { x:  380,
                           y:  330 - Kernel.tick_count % 25,
                           x2: 875,
                           y2: 330,
                           r:  0,
                           g:  0,
                           b:  0,
                           a:  255 }

  args.outputs.lines  << { x:  380 + Kernel.tick_count % 400,
                           y:  290,
                           x2: 875,
                           y2: 290,
                           r:  0,
                           g:  0,
                           b:  0,
                           a:  255 }
end

Solids Borders - main.rb link

# ./samples/01_rendering_basics/03_solids_borders/app/main.rb
=begin
APIs listing that haven't been encountered in a previous sample apps:

- args.outputs.solids: Provided an Array or a Hash, solid squares will be
  rendered to the screen.
- args.outputs.borders: Provided an Array or a Hash, borders
  will be rendered to the screen.
- args.outputs.primitives: Provided an Hash with a :primitive_marker key,
  either a solid square or border will be rendered to the screen.
=end

# The parameters required for rects are:
# 1. The bottom left corner (x, y)
# 2. The width (w)
# 3. The height (h)
# 4. The rgba values for the color and transparency (r, g, b, a)
# [100, 100, 400, 500, 0, 255, 0, 180]
# Whether the rect would be filled or not depends on if
# it is added to args.outputs.solids or args.outputs.borders
# (or its :primitive_marker if Hash is sent to args.outputs.primitives)
def tick args
  args.outputs.labels << { x: 640,
                           y: 700,
                           text: "Sample app shows how to create solid squares and borders.",
                           size_px: 22,
                           anchor_x: 0.5,
                           anchor_y: 0.5 }

  # Render solids/borders using Arrays/Tuples
  # Using arrays is quick and dirty and it's recommended to use Hashes long term
  args.outputs.solids << [470, 520, 50, 50]
  args.outputs.solids << [530, 520, 50, 50, 0, 0, 0]
  args.outputs.solids << [590, 520, 50, 50, 255, 0, 0]
  args.outputs.solids << [650, 520, 50, 50, 255, 0, 0, 128]

  # using Hashes
  args.outputs.solids << { x: 710,
                           y: 520,
                           w: 50,
                           h: 50,
                           r: 0,
                           g: 80,
                           b: 40,
                           a: Kernel.tick_count % 255 }

  # primitives outputs requires a primitive_marker to differentiate
  # between a solid or a border
  args.outputs.primitives << { x: 770,
                               y: 520,
                               w: 50,
                               h: 50,
                               r: 0,
                               g: 80,
                               b: 40,
                               a: Kernel.tick_count % 255,
                               primitive_marker: :solid }

  # using :solid sprite
  args.outputs.sprites << { x: 710,
                            y: 460,
                            w: 50,
                            h: 50,
                            path: :solid,
                            r: 0,
                            g: 80,
                            b: 40,
                            a: Kernel.tick_count % 255 }

  # using :solid sprite does not require a primitive marker
  args.outputs.primitives << { x: 770,
                               y: 460,
                               w: 50,
                               h: 50,
                               path: :solid,
                               r: 0,
                               g: 80,
                               b: 40,
                               a: Kernel.tick_count % 255 }


  # you can also render a border
  # Using arrays is quick and dirty and it's recommended to use Hashes long term
  args.outputs.borders << [470, 320, 50, 50]
  args.outputs.borders << [530, 320, 50, 50, 0, 0, 0]
  args.outputs.borders << [590, 320, 50, 50, 255, 0, 0]
  args.outputs.borders << [650, 320, 50, 50, 255, 0, 0, 128]

  args.outputs.borders << { x: 710,
                            y: 320,
                            w: 50,
                            h: 50,
                            r: 0,
                            g: 80,
                            b: 40,
                            a: Kernel.tick_count % 255 }

  # primitives outputs requires a primitive_marker to differentiate
  # between a solid or a border
  args.outputs.borders << { x: 770,
                            y: 320,
                            w: 50,
                            h: 50,
                            r: 0,
                            g: 80,
                            b: 40,
                            a: Kernel.tick_count % 255,
                            primitive_marker: :border }
end

Sprites - main.rb link

# ./samples/01_rendering_basics/04_sprites/app/main.rb
=begin
APIs listing that haven't been encountered in a previous sample apps:
- args.outputs.sprites: Provided an Array or a Hash, a sprite will be
  rendered to the screen.

Properties of a sprite:
{
  # common properties
  x: 0,
  y: 0,
  w: 100,
  h: 100,
  path: "sprites/square/blue.png",
  angle: 90,
  a: 255,

  # anchoring (float value representing a percentage to offset w and h)
  anchor_x: 0,
  anchor_y: 0,
  angle_anchor_x: 0,
  angle_anchor_y: 0,

  # color saturation
  r: 255,
  g: 255,
  b: 255,

  # flip rendering
  flip_horizontally: false,
  flip_vertically: false

  # sprite sheet properties/clipped rect (using the top-left as the origin)
  tile_x: 0,
  tile_y: 0,
  tile_w: 20,
  tile_h: 20

  # sprite sheet properties/clipped rect (using the bottom-left as the origin)
  source_x: 0,
  source_y: 0,
  source_w: 20,
  source_h: 20,
}
=end
def tick args
  args.outputs.labels << { x: 640,
                           y: 700,
                           text: "Sample app shows how to render a sprite.",
                           size_px: 22,
                           anchor_x: 0.5,
                           anchor_y: 0.5 }

  # ==================
  # ROW 1 Simple Rendering
  # ==================
  args.outputs.labels << { x: 460,
                           y: 600,
                           text: "Simple rendering." }

  # using quick and dirty Array (use Hashes for long term maintainability)
  args.outputs.sprites << [460, 470, 128, 101, 'dragonruby.png']

  # using Hashes
  args.outputs.sprites << { x: 610,
                            y: 470,
                            w: 128,
                            h: 101,
                            path: 'dragonruby.png',
                            a: Kernel.tick_count % 255 }

  args.outputs.sprites << { x: 760 + 64,
                            y: 470 + 50,
                            w: 128,
                            h: 101,
                            anchor_x: 0.5,
                            anchor_y: 0.5,
                            path: 'dragonruby.png',
                            flip_horizontally: true,
                            flip_vertically: true,
                            a: Kernel.tick_count % 255 }

  # ==================
  # ROW 2 Angle/Angle Anchors
  # ==================
  args.outputs.labels << { x: 460,
                           y: 400,
                           text: "Angle/Angle Anchors." }
  # rotation using angle (in degrees)
  args.outputs.sprites << { x: 460,
                            y: 270,
                            w: 128,
                            h: 101,
                            path: 'dragonruby.png',
                            angle: Kernel.tick_count % 360 }

  # rotation anchor using angle_anchor_x
  args.outputs.sprites << { x: 760,
                            y: 270,
                            w: 128,
                            h: 101,
                            path: 'dragonruby.png',
                            angle: Kernel.tick_count % 360,
                            angle_anchor_x: 0,
                            angle_anchor_y: 0 }

  # ==================
  # ROW 3 Sprite Cropping
  # ==================
  args.outputs.labels << { x: 460,
                           y: 200,
                           text: "Cropping (tile sheets)." }

  # tiling using top left as the origin
  args.outputs.sprites << { x: 460,
                            y: 90,
                            w: 80,
                            h: 80,
                            path: 'dragonruby.png',
                            tile_x: 0,
                            tile_y: 0,
                            tile_w: 80,
                            tile_h: 80 }

  # overlay to see how tile_* crops
  args.outputs.sprites << { x: 460,
                            y: 70,
                            w: 128,
                            h: 101,
                            path: 'dragonruby.png',
                            a: 80 }

  # tiling using bottom left as the origin
  args.outputs.sprites << { x: 610,
                            y: 70,
                            w: 80,
                            h: 80,
                            path: 'dragonruby.png',
                            source_x: 0,
                            source_y: 0,
                            source_w: 80,
                            source_h: 80 }

  # overlay to see how source_* crops
  args.outputs.sprites << { x: 610,
                            y: 70,
                            w: 128,
                            h: 101,
                            path: 'dragonruby.png',
                            a: 80 }
end

Sounds - main.rb link

# ./samples/01_rendering_basics/05_sounds/app/main.rb
=begin

 APIs Listing that haven't been encountered in previous sample apps:

 - sample: Chooses random element from array.
   In this sample app, the target note is set by taking a sample from the collection
   of available notes.

 Reminders:

 - String interpolation: Uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

 - args.outputs.labels: An array. The values generate a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGNMENT, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.
=end

# This sample app allows users to test their musical skills by matching the piano sound that plays in each
# level to the correct note.

# Runs all the methods necessary for the game to function properly.
def tick args
  args.outputs.labels << [640, 360, "Click anywhere to play a random sound.", 0, 1]
  args.state.notes ||= [:C3, :D3, :E3, :F3, :G3, :A3, :B3, :C4]

  if args.inputs.mouse.click
    # Play a sound by adding a string to args.outputs.sounds
    args.outputs.sounds << "sounds/#{args.state.notes.sample}.wav" # sound of target note is output
  end
end

Input Basics link

Keyboard - main.rb link

# ./samples/02_input_basics/01_keyboard/app/main.rb
=begin

APIs listing that haven't been encountered in a previous sample apps:

- args.inputs.keyboard.key_up.KEY: The value of the properties will be set
  to the frame  that the key_up event occurred (the frame correlates
  to Kernel.tick_count). Otherwise the value will be nil. For a
  full listing of keys, take a look at mygame/documentation/06-keyboard.md.
- args.state.PROPERTY: The state property on args is a dynamic
  structure. You can define ANY property here with ANY type of
  arbitrary nesting. Properties defined on args.state will be retained
  across frames. If you attempt access a property that doesn't exist
  on args.state, it will simply return nil (no exception will be thrown).

=end

# Along with outputs, inputs are also an essential part of video game development
# DragonRuby can take input from keyboards, mouse, and controllers.
# This sample app will cover keyboard input.

# args.inputs.keyboard.key_up.a will check to see if the a key has been pressed
# This will work with the other keys as well


def tick args
  tick_instructions args, "Sample app shows how keyboard events are registered and accessed.", 360
  args.outputs.labels << { x: 460, y: row_to_px(args, 0), text: "Current game time: #{Kernel.tick_count}", size_enum: -1 }
  args.outputs.labels << { x: 460, y: row_to_px(args, 2), text: "Keyboard input: args.inputs.keyboard.key_up.h", size_enum: -1 }
  args.outputs.labels << { x: 460, y: row_to_px(args, 3), text: "Press \"h\" on the keyboard.", size_enum: -1 }

  # Input on a specifc key can be found through args.inputs.keyboard.key_up followed by the key
  if args.inputs.keyboard.key_up.h
    args.state.h_pressed_at = Kernel.tick_count
  end

  # This code simplifies to if args.state.h_pressed_at has not been initialized, set it to false
  args.state.h_pressed_at ||= false

  if args.state.h_pressed_at
    args.outputs.labels << { x: 460, y: row_to_px(args, 4), text: "\"h\" was pressed at time: #{args.state.h_pressed_at}", size_enum: -1 }
  else
    args.outputs.labels << { x: 460, y: row_to_px(args, 4), text: "\"h\" has never been pressed.", size_enum: -1 }
  end

  tick_help_text args
end

def row_to_px args, row_number, y_offset = 20
  # This takes a row_number and converts it to pixels DragonRuby understands.
  # Row 0 starts 5 units below the top of the grid
  # Each row afterward is 20 units lower
  args.grid.top - 5 - (y_offset * row_number)
end

# Don't worry about understanding the code within this method just yet.
# This method shows you the help text within the game.
def tick_help_text args
  return unless args.state.h_pressed_at

  args.state.key_value_history      ||= {}
  args.state.key_down_value_history ||= {}
  args.state.key_held_value_history ||= {}
  args.state.key_up_value_history   ||= {}

  if (args.inputs.keyboard.key_down.truthy_keys.length > 0 ||
      args.inputs.keyboard.key_held.truthy_keys.length > 0 ||
      args.inputs.keyboard.key_up.truthy_keys.length > 0)
    args.state.help_available = true
    args.state.no_activity_debounce = nil
  else
    args.state.no_activity_debounce ||= 5.seconds
    args.state.no_activity_debounce -= 1
    if args.state.no_activity_debounce <= 0
      args.state.help_available = false
      args.state.key_value_history        = {}
      args.state.key_down_value_history   = {}
      args.state.key_held_value_history   = {}
      args.state.key_up_value_history     = {}
    end
  end

  args.outputs.labels << { x: 10, y: row_to_px(args, 6), text: "This is the api for the keys you've pressed:", size_enum: -1, r: 180 }

  if !args.state.help_available
    args.outputs.labels << [10, row_to_px(args, 7),  "Press a key and I'll show code to access the key and what value will be returned if you used the code."]
    return
  end

  args.outputs.labels << { x: 10 , y: row_to_px(args, 7), text: "args.inputs.keyboard",          size_enum: -2 }
  args.outputs.labels << { x: 330, y: row_to_px(args, 7), text: "args.inputs.keyboard.key_down", size_enum: -2 }
  args.outputs.labels << { x: 650, y: row_to_px(args, 7), text: "args.inputs.keyboard.key_held", size_enum: -2 }
  args.outputs.labels << { x: 990, y: row_to_px(args, 7), text: "args.inputs.keyboard.key_up",   size_enum: -2 }

  fill_history args, :key_value_history,      :down_or_held, nil
  fill_history args, :key_down_value_history, :down,        :key_down
  fill_history args, :key_held_value_history, :held,        :key_held
  fill_history args, :key_up_value_history,   :up,          :key_up

  render_help_labels args, :key_value_history,      :down_or_held, nil,      10
  render_help_labels args, :key_down_value_history, :down,        :key_down, 330
  render_help_labels args, :key_held_value_history, :held,        :key_held, 650
  render_help_labels args, :key_up_value_history,   :up,          :key_up,   990
end

def fill_history args, history_key, state_key, keyboard_method
  fill_single_history args, history_key, state_key, keyboard_method, :raw_key
  fill_single_history args, history_key, state_key, keyboard_method, :char
  args.inputs.keyboard.keys[state_key].each do |key_name|
    fill_single_history args, history_key, state_key, keyboard_method, key_name
  end
end

def fill_single_history args, history_key, state_key, keyboard_method, key_name
  current_value = args.inputs.keyboard.send(key_name)
  if keyboard_method
    current_value = args.inputs.keyboard.send(keyboard_method).send(key_name)
  end
  args.state.as_hash[history_key][key_name] ||= []
  args.state.as_hash[history_key][key_name] << current_value
  args.state.as_hash[history_key][key_name] = args.state.as_hash[history_key][key_name].reverse.uniq.take(3).reverse
end

def render_help_labels args, history_key, state_key, keyboard_method, x
  idx = 8
  args.outputs.labels << args.state
                           .as_hash[history_key]
                           .keys
                           .reverse
                           .map
                           .with_index do |k, i|
    v = args.state.as_hash[history_key][k]
    current_value = args.inputs.keyboard.send(k)
    if keyboard_method
      current_value = args.inputs.keyboard.send(keyboard_method).send(k)
    end
    idx += 2
    [
      { x: x, y: row_to_px(args, idx + 0, 16), text: "    .#{k} is #{current_value || "nil"}", size_enum: -2 },
      { x: x, y: row_to_px(args, idx + 1, 16), text: "       was #{v}", size_enum: -2 }
    ]
  end
end


def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << { x: 0,   y: y - 50, w: 1280, h: 60 }.solid!
  args.outputs.debug << { x: 640, y: y,      text: text,
                          size_enum: 1, alignment_enum: 1, r: 255, g: 255, b: 255 }.label!
  args.outputs.debug << { x: 640, y: y - 25, text: "(click to dismiss instructions)",
                          size_enum: -2, alignment_enum: 1, r: 255, g: 255, b: 255 }.label!
end

Moving A Sprite - main.rb link

# ./samples/02_input_basics/01_moving_a_sprite/app/main.rb
def tick args
  # Create a player and set default values
  # NOTE: args.state is a construct that lets you define properties on the fly
  args.state.player ||= { x: 100,
                          y: 100,
                          w: 50,
                          h: 50,
                          path: 'sprites/square/green.png' }

  # move the player around by consulting args.inputs
  # the top level args.inputs checks the keyboard's arrow keys, WASD,
  # and controller one
  if args.inputs.up
    args.state.player.y += 10
  elsif args.inputs.down
    args.state.player.y -= 10
  end

  if args.inputs.left
    args.state.player.x -= 10
  elsif args.inputs.right
    args.state.player.x += 10
  end

  # Render the player to the screen
  args.outputs.sprites << args.state.player
end

Mouse - main.rb link

# ./samples/02_input_basics/02_mouse/app/main.rb
=begin

APIs that haven't been encountered in a previous sample apps:

- args.inputs.mouse.click: This property will be set if the mouse was clicked.
- args.inputs.mouse.click.point.(x|y): The x and y location of the mouse.
- args.inputs.mouse.click.point.created_at: The frame the mouse click occurred in.
- args.inputs.mouse.click.point.created_at_elapsed: How many frames have passed
  since the click event.

Reminder:

- args.state.PROPERTY: The state property on args is a dynamic
  structure. You can define ANY property here with ANY type of
  arbitrary nesting. Properties defined on args.state will be retained
  across frames. If you attempt access a property that doesn't exist
  on args.state, it will simply return nil (no exception will be thrown).

=end

# This code demonstrates DragonRuby mouse input

# To see if the a mouse click occurred
# Use args.inputs.mouse.click
# Which returns a boolean

# To see where a mouse click occurred
# Use args.inputs.mouse.click.point.x AND
# args.inputs.mouse.click.point.y

# To see which frame the click occurred
# Use args.inputs.mouse.click.created_at

# To see how many frames its been since the click occurred
# Use args.inputs.mouse.click.created_at_elapsed

# Saving the click in args.state can be quite useful

def tick args
  args.outputs.labels << { x: 640,
                           y: 700,
                           anchor_x: 0.5,
                           anchor_y: 0.5,
                           text: "Sample app shows how mouse events are registered and how to measure elapsed time." }
  x = 460

  args.outputs.labels << small_label(args, x, 11, "Mouse input: args.inputs.mouse")

  if args.inputs.mouse.click
    args.state.last_mouse_click = args.inputs.mouse.click
  end

  if args.state.last_mouse_click
    click = args.state.last_mouse_click
    args.outputs.labels << small_label(args, x, 12, "Mouse click happened at: #{click.created_at}")
    args.outputs.labels << small_label(args, x, 13, "Mouse clicked #{click.created_at_elapsed} ticks ago")
    args.outputs.labels << small_label(args, x, 14, "Mouse click location: #{click.point.x}, #{click.point.y}")
  else
    args.outputs.labels << small_label(args, x, 12, "Mouse click has not occurred yet.")
    args.outputs.labels << small_label(args, x, 13, "Please click mouse.")
  end
end

def small_label args, x, row, message
  { x: x,
    y: 720 - 5 - 20 * row,
    text: message }
end

Mouse Properties - main.rb link

# ./samples/02_input_basics/02_mouse_properties/app/main.rb
def tick args
  args.state.properties = [
    { name: "Top Level properties" },
    { name: "mouse.x", value: args.inputs.mouse.x },
    { name: "mouse.y", value: args.inputs.mouse.y },
    { name: "mouse.wheel", value: args.inputs.mouse.wheel },
    { name: "mouse.moved", value: args.inputs.mouse.moved },
    { name: "mouse.moved_at", value: args.inputs.mouse.moved_at },
    { name: "mouse.click", value: args.inputs.mouse.click },
    { name: "mouse.click_at", value: args.inputs.mouse.click_at },
    { name: "mouse.held", value: args.inputs.mouse.held },
    { name: "mouse.held_at", value: args.inputs.mouse.held_at },
    { name: "mouse.up", value: args.inputs.mouse.up },
    { name: "mouse.up_at", value: args.inputs.mouse.up_at },
    { name: "" },
    { name: "Keys" },
    { name: "mouse.key_down.left", value: args.inputs.mouse.key_down.left },
    { name: "mouse.key_held.left", value: args.inputs.mouse.key_held.left },
    { name: "mouse.key_up.left", value: args.inputs.mouse.key_up.left },
    { name: "mouse.key_down.right", value: args.inputs.mouse.key_down.right },
    { name: "mouse.key_held.right", value: args.inputs.mouse.key_held.right },
    { name: "mouse.key_up.right", value: args.inputs.mouse.key_up.right },
    { name: "mouse.button_bits.to_s(2)", value: args.inputs.mouse.button_bits.to_s(2) },
    { name: "mouse.button_left", value: args.inputs.mouse.button_left },
    { name: "mouse.button_right", value: args.inputs.mouse.button_right },
    { name: "" },
    { name: "Buttons" },
    { name: "mouse.button_bits", value: args.inputs.mouse.button_bits.to_s(2) },
    { name: "mouse.button_left", value: args.inputs.mouse.button_left },
    { name: "mouse.buttons.left.click", value: args.inputs.mouse.buttons.left.click },
    { name: "mouse.buttons.left.click_at", value: args.inputs.mouse.buttons.left.click_at },
    { name: "mouse.buttons.left.held", value: args.inputs.mouse.buttons.left.held },
    { name: "mouse.buttons.left.held_at", value: args.inputs.mouse.buttons.left.held_at },
    { name: "mouse.buttons.left.up", value: args.inputs.mouse.buttons.left.up },
    { name: "mouse.buttons.left.up_at", value: args.inputs.mouse.buttons.left.up_at },
    { name: "mouse.buttons.left.buffered_click", value: args.inputs.mouse.buttons.left.buffered_click },
    { name: "mouse.buttons.left.buffered_held", value: args.inputs.mouse.buttons.left.buffered_held },
    { name: "mouse.button_right", value: args.inputs.mouse.button_left },
    { name: "mouse.buttons.right.click", value: args.inputs.mouse.buttons.right.click },
    { name: "mouse.buttons.right.click_at", value: args.inputs.mouse.buttons.right.click_at },
    { name: "mouse.buttons.right.held", value: args.inputs.mouse.buttons.right.held },
    { name: "mouse.buttons.right.held_at", value: args.inputs.mouse.buttons.right.held_at },
    { name: "mouse.buttons.right.up", value: args.inputs.mouse.buttons.right.up },
    { name: "mouse.buttons.right.up_at", value: args.inputs.mouse.buttons.right.up_at },
    { name: "mouse.buttons.right.buffered_click", value: args.inputs.mouse.buttons.right.buffered_click },
    { name: "mouse.buttons.right.buffered_held", value: args.inputs.mouse.buttons.right.buffered_held },
  ]

  args.outputs.primitives << args.state.highlight_fx

  args.outputs.labels << args.state.properties.map_with_index do |property, i|
    text = if property.key?(:value)
             "#{property.name}: #{property.value.inspect}"
           else
             property.name
           end
    {
      x: 16,
      y: 720 - 8 - i * 16,
      text: text,
      size_px: 14
    }
  end
end

Mouse Point To Rect - main.rb link

# ./samples/02_input_basics/03_mouse_point_to_rect/app/main.rb
=begin
- Example usage of Hash#inside_rect? to determine if a mouse click happened
  inside of a box.
  ```
  rect_1 = { x: 100, y: 100, w:   1, h:   1 }
  rect_2 = { x:   0, y:   0, w: 500, h: 500 }
  result = rect_1.inside_rect? rect_2
  ```
=end
def tick args
  # initialize the rectangle
  args.state.box ||= { x: 785, y: 370, w: 50, h: 50, r: 0, g: 0, b: 170 }

  # store the mouse click and the frame the click occured
  # and whether it was inside or outside the box
  if args.inputs.mouse.click
    args.state.last_mouse_click = args.inputs.mouse.click
    args.state.last_mouse_click_at = Kernel.tick_count
    if args.state.last_mouse_click.inside_rect? args.state.box
      args.state.was_inside_rect = true
    else
      args.state.was_inside_rect = false
    end
  end

  # render
  args.outputs.labels << { x: 640, y: 700, anchor_x: 0.5, anchor_y: 0.5, text: "Sample app shows how to determine if a click happened inside a rectangle." }
  args.outputs.labels << { x: 340, y: 420, text:  "Click inside (or outside) the blue box ---->" }

  args.outputs.borders << args.state.box

  if args.state.last_mouse_click
    if args.state.was_inside_rect
      args.outputs.labels << { x: 810,
                               y: 340,
                               anchor_x: 0.5,
                               anchor_y: 0.5,
                               text: "Mouse click happened *inside* the box [frame #{args.state.last_mouse_click_at}]." }
    else
      args.outputs.labels << { x: 810,
                               y: 340,
                               anchor_x: 0.5,
                               anchor_y: 0.5,
                               text: "Mouse click happened *outside* the box [frame #{args.state.last_mouse_click_at}]." }
    end
  else
    args.outputs.labels << { x: 810,
                             y: 340,
                             anchor_x: 0.5,
                             anchor_y: 0.5,
                             text: "Waiting for mouse click..." }
  end
end

Mouse Drag And Drop - main.rb link

# ./samples/02_input_basics/04_mouse_drag_and_drop/app/main.rb
def tick args
  # create 10 random squares on the screen
  if !args.state.squares
    # the squares will be contained in lookup/Hash so that we can access via their id
    args.state.squares = {}
    10.times_with_index do |id|
      # for each square, store it in the hash with
      # the id (we're just using the index 0-9 as the index)
      args.state.squares[id] = {
        id: id,
        x: 100 + (rand * 1080),
        y: 100 + (520 * rand),
        w: 100,
        h: 100,
        path: "sprites/square/blue.png"
      }
    end
  end

  # two key variables are set here
  # - square_reference: this represents the square that is currently being dragged
  # - square_under_mouse: this represents the square that the mouse is currently being hovered over
  if args.state.currently_dragging_square_id
    # if the currently_dragging_square_id is set, then set the "square_under_mouse" to
    # the same square as square_reference
    square_reference = args.state.squares[args.state.currently_dragging_square_id]
    square_under_mouse = square_reference
  else
    # if currently_dragging_square_id isn't set, then see if there is a square that
    # the mouse is currently hovering over (the square reference will be nil since
    # we haven't selected a drag target yet)
    square_under_mouse = args.geometry.find_intersect_rect args.inputs.mouse, args.state.squares.values
    square_reference = nil
  end


  # if a click occurs, and there is a square under the mouse
  if args.inputs.mouse.click && square_under_mouse
    # capture the id of the square that the mouse is hovering over
    args.state.currently_dragging_square_id = square_under_mouse.id

    # also capture where in the square the mouse was clicked so that
    # the movement of the square will smoothly transition with the mouse's
    # location
    args.state.mouse_point_inside_square = {
      x: args.inputs.mouse.x - square_under_mouse.x,
      y: args.inputs.mouse.y - square_under_mouse.y,
    }
  elsif args.inputs.mouse.held && args.state.currently_dragging_square_id
    # if the mouse is currently being held and the currently_dragging_square_id was set,
    # then update the x and y location of the referenced square (taking into consideration the
    # relative position of the mouse when the square was clicked)
    square_reference.x = args.inputs.mouse.x - args.state.mouse_point_inside_square.x
    square_reference.y = args.inputs.mouse.y - args.state.mouse_point_inside_square.y
  elsif args.inputs.mouse.up
    # if the mouse is released, then clear out the currently_dragging_square_id
    args.state.currently_dragging_square_id = nil
  end

  # render all the squares on the screen
  args.outputs.sprites << args.state.squares.values

  # if there was a square under the mouse, add an "overlay"
  if square_under_mouse
    args.outputs.sprites << square_under_mouse.merge(path: "sprites/square/red.png")
  end
end

Mouse Rect To Rect - main.rb link

# ./samples/02_input_basics/04_mouse_rect_to_rect/app/main.rb
=begin

APIs that haven't been encountered in a previous sample apps:

- args.outputs.borders: An array. Values in this array will be rendered as
  unfilled rectangles on the screen.
- ARRAY#intersect_rect?: An array with at least four values is
  considered a rect. The intersect_rect? function returns true
  or false depending on if the two rectangles intersect.

  ```
  # Rect One: x: 100, y: 100, w: 100, h: 100
  # Rect Two: x: 0, y: 0, w: 500, h: 500
  # Result:   true

  [100, 100, 100, 100].intersect_rect? [0, 0, 500, 500]
  ```

  ```
  # Rect One: x: 100, y: 100, w: 10, h: 10
  # Rect Two: x: 500, y: 500, w: 10, h: 10
  # Result:   false

  [100, 100, 10, 10].intersect_rect? [500, 500, 10, 10]
  ```

=end

# Similarly, whether rects intersect can be found through
# rect1.intersect_rect? rect2

def tick args
  tick_instructions args, "Sample app shows how to determine if two rectangles intersect."
  x = 460

  args.outputs.labels << small_label(args, x, 3, "Click anywhere on the screen")
  # red_box = [460, 250, 355, 90, 170, 0, 0]
  # args.outputs.borders << red_box

  # args.state.box_collision_one and args.state.box_collision_two
  # Are given values of a solid when they should be rendered
  # They are stored in game so that they do not get reset every tick
  if args.inputs.mouse.click
    if !args.state.box_collision_one
      args.state.box_collision_one = { x: args.inputs.mouse.click.point.x - 25,
                                       y: args.inputs.mouse.click.point.y - 25,
                                       w: 125, h: 125,
                                       r: 180, g: 0, b: 0, a: 180 }
    elsif !args.state.box_collision_two
      args.state.box_collision_two = { x: args.inputs.mouse.click.point.x - 25,
                                       y: args.inputs.mouse.click.point.y - 25,
                                       w: 125, h: 125,
                                       r: 0, g: 0, b: 180, a: 180 }
    else
      args.state.box_collision_one = nil
      args.state.box_collision_two = nil
    end
  end

  if args.state.box_collision_one
    args.outputs.solids << args.state.box_collision_one
  end

  if args.state.box_collision_two
    args.outputs.solids << args.state.box_collision_two
  end

  if args.state.box_collision_one && args.state.box_collision_two
    if args.state.box_collision_one.intersect_rect? args.state.box_collision_two
      args.outputs.labels << small_label(args, x, 4, 'The boxes intersect.')
    else
      args.outputs.labels << small_label(args, x, 4, 'The boxes do not intersect.')
    end
  else
    args.outputs.labels << small_label(args, x, 4, '--')
  end
end

def small_label args, x, row, message
  { x: x, y: row_to_px(args, row), text: message, size_enum: -2 }
end

def row_to_px args, row_number
  args.grid.top - 5 - (20 * row_number)
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Controller - main.rb link

# ./samples/02_input_basics/05_controller/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - args.current_controller.key_held.KEY: Will check to see if a specific key
   is being held down on the controller.
   If there is more than one controller being used, they can be differentiated by
   using names like controller_one and controller_two.

   For a full listing of buttons, take a look at mygame/documentation/08-controllers.md.

 Reminder:

 - args.state.PROPERTY: The state property on args is a dynamic
   structure. You can define ANY property here with ANY type of
   arbitrary nesting. Properties defined on args.state will be retained
   across frames. If you attempt to access a property that doesn't exist
   on args.state, it will simply return nil (no exception will be thrown).

   In this sample app, args.state.BUTTONS is an array that stores the buttons of the controller.
   The parameters of a button are:
   1. the position (x, y)
   2. the input key held on the controller
   3. the text or name of the button

=end

# This sample app provides a visual demonstration of a standard controller, including
# the placement and function of all buttons.

class ControllerDemo
  attr_accessor :inputs, :state, :outputs

  # Calls the methods necessary for the app to run successfully.
  def tick
    process_inputs
    render
  end

  # Starts with an empty collection of buttons.
  # Adds buttons that are on the controller to the collection.
  def process_inputs
    state.target  ||= :controller_one
    state.buttons = []

    if inputs.keyboard.key_down.tab
      if state.target == :controller_one
        state.target = :controller_two
      elsif state.target == :controller_two
        state.target = :controller_three
      elsif state.target == :controller_three
        state.target = :controller_four
      elsif state.target == :controller_four
        state.target = :controller_one
      end
    end

    state.buttons << { x: 100,  y: 500, active: current_controller.key_held.l1, text: "L1"}
    state.buttons << { x: 100,  y: 600, active: current_controller.key_held.l2, text: "L2"}
    state.buttons << { x: 1100, y: 500, active: current_controller.key_held.r1, text: "R1"}
    state.buttons << { x: 1100, y: 600, active: current_controller.key_held.r2, text: "R2"}
    state.buttons << { x: 540,  y: 450, active: current_controller.key_held.select, text: "Select"}
    state.buttons << { x: 660,  y: 450, active: current_controller.key_held.start, text: "Start"}
    state.buttons << { x: 200,  y: 300, active: current_controller.key_held.left, text: "Left"}
    state.buttons << { x: 300,  y: 400, active: current_controller.key_held.up, text: "Up"}
    state.buttons << { x: 400,  y: 300, active: current_controller.key_held.right, text: "Right"}
    state.buttons << { x: 300,  y: 200, active: current_controller.key_held.down, text: "Down"}
    state.buttons << { x: 800,  y: 300, active: current_controller.key_held.x, text: "X"}
    state.buttons << { x: 900,  y: 400, active: current_controller.key_held.y, text: "Y"}
    state.buttons << { x: 1000, y: 300, active: current_controller.key_held.a, text: "A"}
    state.buttons << { x: 900,  y: 200, active: current_controller.key_held.b, text: "B"}
    state.buttons << { x: 450 + current_controller.left_analog_x_perc * 100,
                       y: 100 + current_controller.left_analog_y_perc * 100,
                       active: current_controller.key_held.l3,
                       text: "L3" }
    state.buttons << { x: 750 + current_controller.right_analog_x_perc * 100,
                       y: 100 + current_controller.right_analog_y_perc * 100,
                       active: current_controller.key_held.r3,
                       text: "R3" }
  end

  # Gives each button a square shape.
  # If the button is being pressed or held (which means it is considered active),
  # the square is filled in. Otherwise, the button simply has a border.
  def render
    state.buttons.each do |b|
      rect = { x: b.x, y: b.y, w: 75, h: 75 }

      if b.active # if button is pressed
        outputs.solids << rect # rect is output as solid (filled in)
      else
        outputs.borders << rect # otherwise, output as border
      end

      # Outputs the text of each button using labels.
      outputs.labels << { x: b.x, y: b.y + 95, text: b.text } # add 95 to place label above button
    end

    outputs.labels << { x:  10, y: 60, text: "Left Analog x: #{current_controller.left_analog_x_raw} (#{current_controller.left_analog_x_perc * 100}%)" }
    outputs.labels << { x:  10, y: 30, text: "Left Analog y: #{current_controller.left_analog_y_raw} (#{current_controller.left_analog_y_perc * 100}%)" }
    outputs.labels << { x: 1270, y: 60, text: "Right Analog x: #{current_controller.right_analog_x_raw} (#{current_controller.right_analog_x_perc * 100}%)", alignment_enum: 2 }
    outputs.labels << { x: 1270, y: 30, text: "Right Analog y: #{current_controller.right_analog_y_raw} (#{current_controller.right_analog_y_perc * 100}%)" , alignment_enum: 2 }

    outputs.labels << { x: 640, y: 60, text: "Target: #{state.target} (press tab to go to next controller)", alignment_enum: 1 }
    outputs.labels << { x: 640, y: 30, text: "Connected: #{current_controller.connected}", alignment_enum: 1 }
  end

  def current_controller
    if state.target == :controller_one
      return inputs.controller_one
    elsif state.target == :controller_two
      return inputs.controller_two
    elsif state.target == :controller_three
      return inputs.controller_three
    elsif state.target == :controller_four
      return inputs.controller_four
    end
  end
end

$controller_demo = ControllerDemo.new

def tick args
  tick_instructions args, "Sample app shows how controller input is handled. You'll need to connect a USB controller."
  $controller_demo.inputs = args.inputs
  $controller_demo.state = args.state
  $controller_demo.outputs = args.outputs
  $controller_demo.tick
end

# Resets the app.
def r
  $gtk.reset
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Touch - main.rb link

# ./samples/02_input_basics/06_touch/app/main.rb
def tick args
  args.outputs.background_color = [ 0, 0, 0 ]
  args.outputs.primitives << [640, 700, "Touch your screen.", 5, 1, 255, 255, 255].label

  # If you don't want to get fancy, you can just look for finger_one
  #  (and _two, if you like), which are assigned in the order new touches hit
  #  the screen. If not nil, they are touching right now, and are just
  #  references to specific items in the args.input.touch hash.
  # If finger_one lifts off, it will become nil, but finger_two, if it was
  #  touching, remains until it also lifts off. When all fingers lift off, the
  #  the next new touch will be finger_one again, but until then, new touches
  #  don't fill in earlier slots.
  if !args.inputs.finger_one.nil?
    args.outputs.primitives << { x: 640, y: 650, text: "Finger #1 is touching at (#{args.inputs.finger_one.x}, #{args.inputs.finger_one.y}).",
                                 size_enum: 5, alignment_enum: 1, r: 255, g: 255, b: 255 }.label!
  end
  if !args.inputs.finger_two.nil?
    args.outputs.primitives << { x: 640, y: 600, text: "Finger #2 is touching at (#{args.inputs.finger_two.x}, #{args.inputs.finger_two.y}).",
                                 size_enum: 5, alignment_enum: 1, r: 255, g: 255, b: 255 }.label!
  end

  # Here's the more flexible interface: this will report as many simultaneous
  #  touches as the system can handle, but it's a little more effort to track
  #  them. Each item in the args.input.touch hash has a unique key (an
  #  incrementing integer) that exists until the finger lifts off. You can
  #  tell which order the touches happened globally by the key value, or
  #  by the touch[id].touch_order field, which resets to zero each time all
  #  touches have lifted.

  args.state.colors ||= [
    0xFF0000, 0x00FF00, 0x1010FF, 0xFFFF00, 0xFF00FF, 0x00FFFF, 0xFFFFFF
  ]

  size = 100
  args.inputs.touch.each { |k,v|
    color = args.state.colors[v.touch_order % 7]
    r = (color & 0xFF0000) >> 16
    g = (color & 0x00FF00) >> 8
    b = (color & 0x0000FF)
    args.outputs.primitives << { x: v.x - (size / 2), y: v.y + (size / 2), w: size, h: size, r: r, g: g, b: b, a: 255 }.solid!
    args.outputs.primitives << { x: v.x, y: v.y + size, text: k.to_s, alignment_enum: 1 }.label!
  }
end

Managing Scenes - main.rb link

# ./samples/02_input_basics/07_managing_scenes/app/main.rb
def tick args
  # initialize the scene to scene 1
  args.state.current_scene ||= :title_scene
  # capture the current scene to verify it didn't change through
  # the duration of tick
  current_scene = args.state.current_scene

  # tick whichever scene is current
  case current_scene
  when :title_scene
    tick_title_scene args
  when :game_scene
    tick_game_scene args
  when :game_over_scene
    tick_game_over_scene args
  end

  # make sure that the current_scene flag wasn't set mid tick
  if args.state.current_scene != current_scene
    raise "Scene was changed incorrectly. Set args.state.next_scene to change scenes."
  end

  # if next scene was set/requested, then transition the current scene to the next scene
  if args.state.next_scene
    args.state.current_scene = args.state.next_scene
    args.state.next_scene = nil
  end
end

def tick_title_scene args
  args.outputs.labels << { x: 640,
                           y: 360,
                           text: "Title Scene (click to go to game)",
                           alignment_enum: 1 }

  if args.inputs.mouse.click
    args.state.next_scene = :game_scene
  end
end

def tick_game_scene args
  args.outputs.labels << { x: 640,
                           y: 360,
                           text: "Game Scene (click to go to game over)",
                           alignment_enum: 1 }

  if args.inputs.mouse.click
    args.state.next_scene = :game_over_scene
  end
end

def tick_game_over_scene args
  args.outputs.labels << { x: 640,
                           y: 360,
                           text: "Game Over Scene (click to go to title)",
                           alignment_enum: 1 }

  if args.inputs.mouse.click
    args.state.next_scene = :title_scene
  end
end

Rendering Sprites link

Animation Using Separate Pngs - main.rb link

# ./samples/03_rendering_sprites/01_animation_using_separate_pngs/app/main.rb
=begin
 Reminders:

 - String interpolation: Uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

   In this sample app, we're using string interpolation to iterate through images in the
   sprites folder using their image path names.

 - args.outputs.sprites: An array. Values in this array generate sprites on the screen.
   The parameters are [X, Y, WIDTH, HEIGHT, IMAGE PATH]
   For more information about sprites, go to mygame/documentation/05-sprites.md.

 - args.outputs.labels: An array. Values in the array generate labels on the screen.
   The parameters are [X, Y, TEXT, SIZE, ALIGNMENT, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.

 - args.inputs.keyboard.key_down.KEY: Determines if a key is in the down state, or pressed.
   Stores the frame that key was pressed on.
   For more information about the keyboard, go to mygame/documentation/06-keyboard.md.

=end

# This sample app demonstrates how sprite animations work.
# There are two sprites that animate forever and one sprite
# that *only* animates when you press the "f" key on the keyboard.

# This is the entry point to your game. The `tick` method
# executes at 60 frames per second. There are two methods
# in this tick "entry point": `looping_animation`, and the
# second method is `one_time_animation`.
def tick args
  # uncomment the line below to see animation play out in slow motion
  # args.gtk.slowmo! 6
  looping_animation args
  one_time_animation args
end

# This function shows how to animate a sprite that loops forever.
def looping_animation args
  # Here we define a few local variables that will be sent
  # into the magic function that gives us the correct sprite image
  # over time. There are four things we need in order to figure
  # out which sprite to show.

  # 1. When to start the animation.
  start_looping_at = 0

  # 2. The number of pngs that represent the full animation.
  number_of_sprites = 6

  # 3. How long to show each png.
  number_of_frames_to_show_each_sprite = 4

  # 4. Whether the animation should loop once, or forever.
  does_sprite_loop = true

  # With the variables defined above, we can get a number
  # which represents the sprite to show by calling the `frame_index` function.
  # In this case the number will be between 0, and 5 (you can see the sprites
  # in the ./sprites directory).
  sprite_index = start_looping_at.frame_index number_of_sprites,
                                              number_of_frames_to_show_each_sprite,
                                              does_sprite_loop

  # Now that we have `sprite_index, we can present the correct file.
  args.outputs.sprites << { x: 100,
                            y: 100,
                            w: 100,
                            h: 100,
                            path: "sprites/dragon_fly_#{sprite_index}.png" }

  # Try changing the numbers below to see how the animation changes:
  args.outputs.sprites << { x: 100,
                            y: 200,
                            w: 100,
                            h: 100,
                            path: "sprites/dragon_fly_#{0.frame_index 6, 4, true}.png" }
end

# This function shows how to animate a sprite that executes
# only once when the "f" key is pressed.
def one_time_animation args
  # This is just a label the shows instructions within the game.
  args.outputs.labels <<  { x: 220, y: 350, text: "(press f to animate)" }

  # If "f" is pressed on the keyboard...
  if args.inputs.keyboard.key_down.f
    # Print the frame that "f" was pressed on.
    puts "Hello from main.rb! The \"f\" key was in the down state on frame: #{Kernel.tick_count}"

    # And MOST IMPORTANTLY set the point it time to start the animation,
    # equal to "now" which is represented as Kernel.tick_count.

    # Also IMPORTANT, you'll notice that the value of when to start looping
    # is stored in `args.state`. This construct's values are retained across
    # executions of the `tick` method.
    args.state.start_looping_at = Kernel.tick_count
  end

  # These are the same local variables that were defined
  # for the `looping_animation` function.
  number_of_sprites = 6
  number_of_frames_to_show_each_sprite = 4

  # Except this sprite does not loop again. If the animation time has passed,
  # then the frame_index function returns nil.
  does_sprite_loop = false

  if args.state.start_looping_at
    sprite_index = args.state
                       .start_looping_at
                       .frame_index number_of_sprites,
                                    number_of_frames_to_show_each_sprite,
                                    does_sprite_loop
  end

  # This line sets the frame index to zero, if
  # the animation duration has passed (frame_index returned nil).

  # Remeber: we are not looping forever here.
  sprite_index ||= 0

  # Present the sprite.
  args.outputs.sprites << { x: 100,
                            y: 300,
                            w: 100,
                            h: 100,
                            path: "sprites/dragon_fly_#{sprite_index}.png" }

  args.outputs.labels << { x: 640,
                           y: 700,
                           text: "Sample app shows how to use Numeric#frame_index to animate a sprite over time.",
                           anchor_x: 0.5,
                           anchor_y: 0.5 }
end

Animation Using Sprite Sheet - main.rb link

# ./samples/03_rendering_sprites/02_animation_using_sprite_sheet/app/main.rb
def tick args
  args.state.player ||= { x: 100,
                          y: 100,
                          w: 64,
                          h: 64,
                          direction: 1,
                          is_moving: false }

  # get the keyboard input and set player properties
  if args.inputs.keyboard.right
    args.state.player.x += 3
    args.state.player.direction = 1
    args.state.player.started_running_at ||= Kernel.tick_count
  elsif args.inputs.keyboard.left
    args.state.player.x -= 3
    args.state.player.direction = -1
    args.state.player.started_running_at ||= Kernel.tick_count
  end

  if args.inputs.keyboard.up
    args.state.player.y += 1
    args.state.player.started_running_at ||= Kernel.tick_count
  elsif args.inputs.keyboard.down
    args.state.player.y -= 1
    args.state.player.started_running_at ||= Kernel.tick_count
  end

  # if no arrow keys are being pressed, set the player as not moving
  if !args.inputs.keyboard.directional_vector
    args.state.player.started_running_at = nil
  end

  # wrap player around the stage
  if args.state.player.x > 1280
    args.state.player.x = -64
    args.state.player.started_running_at ||= Kernel.tick_count
  elsif args.state.player.x < -64
    args.state.player.x = 1280
    args.state.player.started_running_at ||= Kernel.tick_count
  end

  if args.state.player.y > 720
    args.state.player.y = -64
    args.state.player.started_running_at ||= Kernel.tick_count
  elsif args.state.player.y < -64
    args.state.player.y = 720
    args.state.player.started_running_at ||= Kernel.tick_count
  end

  # render player as standing or running
  if args.state.player.started_running_at
    args.outputs.sprites << running_sprite(args)
  else
    args.outputs.sprites << standing_sprite(args)
  end
  args.outputs.labels << [30, 700, "Use arrow keys to move around."]
end

def standing_sprite args
  {
    x: args.state.player.x,
    y: args.state.player.y,
    w: args.state.player.w,
    h: args.state.player.h,
    path: "sprites/horizontal-stand.png",
    flip_horizontally: args.state.player.direction > 0
  }
end

def running_sprite args
  if !args.state.player.started_running_at
    tile_index = 0
  else
    how_many_frames_in_sprite_sheet = 6
    how_many_ticks_to_hold_each_frame = 3
    should_the_index_repeat = true
    tile_index = args.state
                     .player
                     .started_running_at
                     .frame_index(how_many_frames_in_sprite_sheet,
                                  how_many_ticks_to_hold_each_frame,
                                  should_the_index_repeat)
  end

  {
    x: args.state.player.x,
    y: args.state.player.y,
    w: args.state.player.w,
    h: args.state.player.h,
    path: 'sprites/horizontal-run.png',
    tile_x: 0 + (tile_index * args.state.player.w),
    tile_y: 0,
    tile_w: args.state.player.w,
    tile_h: args.state.player.h,
    flip_horizontally: args.state.player.direction > 0
  }
end

Animation States 1 - main.rb link

# ./samples/03_rendering_sprites/03_animation_states_1/app/main.rb
class Game
  attr_gtk

  def defaults
    state.show_debug_layer = true if Kernel.tick_count == 0

    state.player ||= {
      tile_size: 64,
      speed: 3,
      slash_frames: 15,
      x: 50,
      y: 400,
      dir_x: 1,
      dir_y: -1,
      is_moving: false
    }

    state.enemies ||= []
  end

  def add_enemy
    state.enemies << {
      x: 1200 * rand,
      y: 600 * rand,
      w: 64,
      h: 64,
      anchor_x: 0.5,
      anchor_y: 0.5,
      path: 'sprites/enemy.png'
    }
  end

  def sprite_horizontal_run
    tile_index = 0.frame_index(6, 3, true)
    tile_index = 0 if !player.is_moving

    {
      x: player.x,
      y: player.y,
      w: player.tile_size,
      h: player.tile_size,
      anchor_x: 0.5,
      anchor_y: 0.5,
      path: 'sprites/horizontal-run.png',
      tile_x: 0 + (tile_index * player.tile_size),
      tile_y: 0,
      tile_w: player.tile_size,
      tile_h: player.tile_size,
      flip_horizontally: player.dir_x > 0,
    }
  end

  def sprite_horizontal_stand
    {
      x: player.x,
      y: player.y,
      w: player.tile_size,
      h: player.tile_size,
      anchor_x: 0.5,
      anchor_y: 0.5,
      path: 'sprites/horizontal-stand.png',
      flip_horizontally: player.dir_x > 0,
    }
  end

  def sprite_horizontal_slash
    tile_index   = player.slash_at.frame_index(5, player.slash_frames.idiv(5), false) || 0

    {
      x: player.x + player.dir_x.sign * 9.25,
      y: player.y + 9.25,
      w: 165,
      h: 165,
      anchor_x: 0.5,
      anchor_y: 0.5,
      path: 'sprites/horizontal-slash.png',
      tile_x: 0 + (tile_index * 128),
      tile_y: 0,
      tile_w: 128,
      tile_h: 128,
      flip_horizontally: player.dir_x > 0
    }
  end

  def render_player
    if player.slash_at
      outputs.sprites << sprite_horizontal_slash
    elsif player.is_moving
      outputs.sprites << sprite_horizontal_run
    else
      outputs.sprites << sprite_horizontal_stand
    end
  end

  def render_enemies
    outputs.borders << state.enemies
  end

  def render_debug_layer
    return if !state.show_debug_layer
    outputs.borders << player.slash_collision_rect
  end

  def slash_initiate?
    inputs.controller_one.key_down.a || inputs.keyboard.key_down.j
  end

  def input
    # player movement
    if slash_complete? && (vector = inputs.directional_vector)
      player.x += vector.x * player.speed
      player.y += vector.y * player.speed
    end
    player.slash_at = slash_initiate? if slash_initiate?
  end

  def calc_movement
    # movement
    if vector = inputs.directional_vector
      state.debug_label = vector
      player.dir_x = vector.x if vector.x != 0
      player.dir_y = vector.y if vector.y != 0
      player.is_moving = true
    else
      state.debug_label = vector
      player.is_moving = false
    end
  end

  def calc_slash
    player.slash_collision_rect = {
      x: player.x + player.dir_x.sign * 52,
      y: player.y,
      w: 40,
      h: 20,
      anchor_x: 0.5,
      anchor_y: 0.5,
      path: "sprites/debug-slash.png"
    }

    # recalc sword's slash state
    player.slash_at = nil if slash_complete?

    # determine collision if the sword is at it's point of damaging
    return unless slash_can_damage?

    state.enemies.reject! { |e| e.intersect_rect? player.slash_collision_rect }
  end

  def slash_complete?
    !player.slash_at || player.slash_at.elapsed?(player.slash_frames)
  end

  def slash_can_damage?
    # damage occurs half way into the slash animation
    return false if slash_complete?
    return false if (player.slash_at + player.slash_frames.idiv(2)) != Kernel.tick_count
    return true
  end

  def calc
    # generate an enemy if there aren't any on the screen
    add_enemy if state.enemies.length == 0
    calc_movement
    calc_slash
  end

  # source is at http://github.com/amirrajan/dragonruby-link-to-the-past
  def tick
    defaults
    render_enemies
    render_player
    outputs.labels << [30, 30, "Gamepad: D-Pad to move. B button to attack."]
    outputs.labels << [30, 52, "Keyboard: WASD/Arrow keys to move. J to attack."]
    render_debug_layer
    input
    calc
  end

  def player
    state.player
  end
end

$game = Game.new

def tick args
  $game.args = args
  $game.tick
end

$gtk.reset

Animation States 2 - main.rb link

# ./samples/03_rendering_sprites/03_animation_states_2/app/main.rb
def tick args
  defaults args
  input args
  calc args
  render args
end

def defaults args
  # uncomment the line below to slow the game down by a factor of 4 -> 15 fps (for debugging)
  # args.gtk.slowmo! 4

  args.state.player ||= {
    x: 144,                # render x of the player
    y: 32,                 # render y of the player
    w: 144 * 2,            # render width of the player
    h: 72 * 2,             # render height of the player
    dx: 0,                 # velocity x of the player
    action: :standing,     # current action/status of the player
    action_at: 0,          # frame that the action occurred
    previous_direction: 1, # direction the player was facing last frame
    direction: 1,          # direction the player is facing this frame
    launch_speed: 4,       # speed the player moves when they start running
    run_acceleration: 1,   # how much the player accelerates when running
    run_top_speed: 8,      # the top speed the player can run
    friction: 0.9,         # how much the player slows down when have stopped attempting to run
    anchor_x: 0.5,         # render anchor x of the player
    anchor_y: 0            # render anchor y of the player
  }
end

def input args
  # if the directional has been pressed on the input device
  if args.inputs.left_right != 0
    # determine if the player is currently running or not,
    # if they aren't, set their dx to their launch speed
    # otherwise, add the run acceleration to their dx
    if args.state.player.action != :running
      args.state.player.dx = args.state.player.launch_speed * args.inputs.left_right.sign
    else
      args.state.player.dx += args.inputs.left_right * args.state.player.run_acceleration
    end

    # capture the direction the player is facing and the previous direction
    args.state.player.previous_direction = args.state.player.direction
    args.state.player.direction = args.inputs.left_right.sign
  end
end

def calc args
  # clamp the player's dx to the top speed
  args.state.player.dx = args.state.player.dx.clamp(-args.state.player.run_top_speed, args.state.player.run_top_speed)

  # move the player by their dx
  args.state.player.x += args.state.player.dx

  # capture the player's hitbox
  player_hitbox = hitbox args.state.player

  # check boundary collisions and stop the player if they are colliding with the ednges of the screen
  if (player_hitbox.x - player_hitbox.w / 2) < 0
    args.state.player.x = player_hitbox.w / 2
    args.state.player.dx = 0
    # if the player is not standing, set them to standing and capture the frame
    if args.state.player.action != :standing
      args.state.player.action = :standing
      args.state.player.action_at = Kernel.tick_count
    end
  elsif (player_hitbox.x + player_hitbox.w / 2) > 1280
    args.state.player.x = 1280 - player_hitbox.w / 2
    args.state.player.dx = 0

    # if the player is not standing, set them to standing and capture the frame
    if args.state.player.action != :standing
      args.state.player.action = :standing
      args.state.player.action_at = Kernel.tick_count
    end
  end

  # if the player's dx is not 0, they are running. update their action and capture the frame if needed
  if args.state.player.dx.abs > 0
    if args.state.player.action != :running || args.state.player.direction != args.state.player.previous_direction
      args.state.player.action = :running
      args.state.player.action_at = Kernel.tick_count
    end
  elsif args.inputs.left_right == 0
    # if the player's dx is 0 and they are not currently trying to run (left_right == 0), set them to standing and capture the frame
    if args.state.player.action != :standing
      args.state.player.action = :standing
      args.state.player.action_at = Kernel.tick_count
    end
  end

  # if the player is not trying to run (left_right == 0), slow them down by the friction amount
  if args.inputs.left_right == 0
    args.state.player.dx *= args.state.player.friction

    # if the player's dx is less than 1, set it to 0
    if args.state.player.dx.abs < 1
      args.state.player.dx = 0
    end
  end
end

def render args
  # determine if the player should be flipped horizontally
  flip_horizontally = args.state.player.direction == -1
  # determine the path to the sprite to render, the idle sprite is used if action == :standing
  path = "sprites/link-idle.png"

  # if the player is running, determine the frame to render
  if args.state.player.action == :running
    # the sprite animation's first 3 frames represent the launch of the run, so we skip them on the animation loop
    # by setting the repeat_index to 3 (the 4th frame)
    frame_index = args.state.player.action_at.frame_index(count: 9, hold_for: 8, repeat: true, repeat_index: 3)
    path = "sprites/link-run-#{frame_index}.png"

    args.outputs.labels << { x: args.state.player.x - 144, y: args.state.player.y + 230, text: "action:      #{args.state.player.action}" }
    args.outputs.labels << { x: args.state.player.x - 144, y: args.state.player.y + 200, text: "action_at:   #{args.state.player.action_at}" }
    args.outputs.labels << { x: args.state.player.x - 144, y: args.state.player.y + 170, text: "frame_index: #{frame_index}" }
  else
    args.outputs.labels << { x: args.state.player.x - 144, y: args.state.player.y + 230, text: "action:      #{args.state.player.action}" }
    args.outputs.labels << { x: args.state.player.x - 144, y: args.state.player.y + 200, text: "action_at:   #{args.state.player.action_at}" }
    args.outputs.labels << { x: args.state.player.x - 144, y: args.state.player.y + 170, text: "frame_index: n/a" }
  end


  # render the player's hitbox and sprite (the hitbox is used to determine boundary collision)
  args.outputs.borders << hitbox(args.state.player)
  args.outputs.borders << args.state.player

  # render the player's sprite
  args.outputs.sprites << args.state.player.merge(path: path, flip_horizontally: flip_horizontally)
end

def hitbox entity
  {
    x: entity.x,
    y: entity.y + 5,
    w: 64,
    h: 96,
    anchor_x: 0.5,
    anchor_y: 0
  }
end


$gtk.reset

Animation States 3 - main.rb link

# ./samples/03_rendering_sprites/03_animation_states_3/app/main.rb
class Game
  attr_gtk

  def request_action name, at: nil
    at ||= Kernel.tick_count
    state.player.requested_action = name
    state.player.requested_action_at = at
  end

  def defaults
    state.player.x                  ||= 64
    state.player.y                  ||= 0
    state.player.dx                 ||= 0
    state.player.dy                 ||= 0
    state.player.action             ||= :standing
    state.player.action_at          ||= 0
    state.player.next_action_queue  ||= {}
    state.player.facing             ||= 1
    state.player.jump_at            ||= 0
    state.player.jump_count         ||= 0
    state.player.max_speed          ||= 1.0
    state.sabre.x                   ||= state.player.x
    state.sabre.y                   ||= state.player.y
    state.actions_lookup            ||= new_actions_lookup
  end

  def render
    outputs.background_color = [32, 32, 32]
    outputs[:scene].w = 128
    outputs[:scene].h = 128
    outputs[:scene].borders << { x: 0, y: 0, w: 128, h: 128, r: 255, g: 255, b: 255 }
    render_player
    render_sabre
    args.outputs.sprites << { x: 320, y: 0, w: 640, h: 640, path: :scene }
    args.outputs.labels << { x: 10, y: 100, text: "Controls:", r: 255, g: 255, b: 255, size_enum: -1 }
    args.outputs.labels << { x: 10, y: 80, text: "Move:   left/right", r: 255, g: 255, b: 255, size_enum: -1 }
    args.outputs.labels << { x: 10, y: 60, text: "Jump:   space | up | right click", r: 255, g: 255, b: 255, size_enum: -1 }
    args.outputs.labels << { x: 10, y: 40, text: "Attack: f     | j  | left click", r: 255, g: 255, b: 255, size_enum: -1 }
  end

  def render_sabre
    return if !state.sabre.is_active
    sabre_index = 0.frame_index count:    4,
                                hold_for: 2,
                                repeat:   true
    offset =  0
    offset = -8 if state.player.facing == -1
    outputs[:scene].sprites << { x: state.sabre.x + offset,
                        y: state.sabre.y, w: 16, h: 16, path: "sprites/sabre-throw/#{sabre_index}.png" }
  end

  def new_actions_lookup
    r = {
      slash_0: {
        frame_count: 6,
        interrupt_count: 4,
        path: "sprites/kenobi/slash-0/:index.png"
      },
      slash_1: {
        frame_count: 6,
        interrupt_count: 4,
        path: "sprites/kenobi/slash-1/:index.png"
      },
      throw_0: {
        frame_count: 8,
        throw_frame: 2,
        catch_frame: 6,
        path: "sprites/kenobi/slash-2/:index.png"
      },
      throw_1: {
        frame_count: 9,
        throw_frame: 2,
        catch_frame: 7,
        path: "sprites/kenobi/slash-3/:index.png"
      },
      throw_2: {
        frame_count: 9,
        throw_frame: 2,
        catch_frame: 7,
        path: "sprites/kenobi/slash-4/:index.png"
      },
      slash_5: {
        frame_count: 11,
        path: "sprites/kenobi/slash-5/:index.png"
      },
      slash_6: {
        frame_count: 8,
        interrupt_count: 6,
        path: "sprites/kenobi/slash-6/:index.png"
      }
    }

    r.each.with_index do |(k, v), i|
      v.name               ||= k
      v.index              ||= i

      v.hold_for           ||= 5
      v.duration           ||= v.frame_count * v.hold_for
      v.last_index         ||= v.frame_count - 1

      v.interrupt_count    ||= v.frame_count
      v.interrupt_duration ||= v.interrupt_count * v.hold_for

      v.repeat             ||= false
      v.next_action        ||= r[r.keys[i + 1]]
    end

    r
  end

  def render_player
    flip_horizontally = if state.player.facing == -1
                          true
                        else
                          false
                        end

    player_sprite = { x: state.player.x + 1 - 8,
                      y: state.player.y,
                      w: 16,
                      h: 16,
                      flip_horizontally: flip_horizontally }

    if state.player.action == :standing
      if state.player.y != 0
        if state.player.jump_count <= 1
          outputs[:scene].sprites << { **player_sprite, path: "sprites/kenobi/jumping.png" }
        else
          index = state.player.jump_at.frame_index count: 8, hold_for: 5, repeat: false
          index ||= 7
          outputs[:scene].sprites << { **player_sprite, path: "sprites/kenobi/second-jump/#{index}.png" }
        end
      elsif state.player.dx != 0
        index = state.player.action_at.frame_index count: 4, hold_for: 5, repeat: true
        outputs[:scene].sprites << { **player_sprite, path: "sprites/kenobi/run/#{index}.png" }
      else
        outputs[:scene].sprites << { **player_sprite, path: 'sprites/kenobi/standing.png'}
      end
    else
      v = state.actions_lookup[state.player.action]
      slash_frame_index = state.player.action_at.frame_index count:    v.frame_count,
                                                             hold_for: v.hold_for,
                                                             repeat:   v.repeat
      slash_frame_index ||= v.last_index
      slash_path          = v.path.sub ":index", slash_frame_index.to_s
      outputs[:scene].sprites << { **player_sprite, path: slash_path }
    end
  end

  def calc_input
    if state.player.next_action_queue.length > 2
      raise "Code in calc assums that key length of state.player.next_action_queue will never be greater than 2."
    end

    if inputs.controller_one.key_down.a ||
       inputs.mouse.button_left ||
       inputs.keyboard.key_down.j ||
       inputs.keyboard.key_down.f
      request_action :attack
    end

    should_update_facing = false
    if state.player.action == :standing
      should_update_facing = true
    else
      key_0 = state.player.next_action_queue.keys[0]
      key_1 = state.player.next_action_queue.keys[1]
      if Kernel.tick_count == key_0
        should_update_facing = true
      elsif Kernel.tick_count == key_1
        should_update_facing = true
      elsif key_0 && key_1 && Kernel.tick_count.between?(key_0, key_1)
        should_update_facing = true
      end
    end

    if should_update_facing && inputs.left_right.sign != state.player.facing.sign
      state.player.dx = 0

      if inputs.left
        state.player.facing = -1
      elsif inputs.right
        state.player.facing = 1
      end

      state.player.dx += 0.1 * inputs.left_right
    end

    if state.player.action == :standing
      state.player.dx += 0.1 * inputs.left_right
      if state.player.dx.abs > state.player.max_speed
        state.player.dx = state.player.max_speed * state.player.dx.sign
      end
    end

    was_jump_requested = inputs.keyboard.key_down.up ||
                         inputs.keyboard.key_down.w  ||
                         inputs.mouse.button_right  ||
                         inputs.controller_one.key_down.up ||
                         inputs.controller_one.key_down.b ||
                         inputs.keyboard.key_down.space

    can_jump = state.player.jump_at.elapsed_time > 20
    if state.player.jump_count <= 1
      can_jump = state.player.jump_at.elapsed_time > 10
    end

    if was_jump_requested && can_jump
      if state.player.action == :slash_6
        state.player.action = :standing
      end
      state.player.dy = 1
      state.player.jump_count += 1
      state.player.jump_at     = Kernel.tick_count
    end
  end

  def calc
    calc_input
    calc_requested_action
    calc_next_action
    calc_sabre
    calc_player_movement

    if state.player.y <= 0 && state.player.dy < 0
      state.player.y = 0
      state.player.dy = 0
      state.player.jump_at = 0
      state.player.jump_count = 0
    end
  end

  def calc_player_movement
    state.player.x += state.player.dx
    state.player.y += state.player.dy
    state.player.dy -= 0.05
    if state.player.y <= 0
      state.player.y = 0
      state.player.dy = 0
      state.player.jump_at = 0
      state.player.jump_count = 0
    end

    if state.player.dx.abs < 0.09
      state.player.dx = 0
    end

    state.player.x = 8  if state.player.x < 8
    state.player.x = 120 if state.player.x > 120
  end

  def calc_requested_action
    return if !state.player.requested_action
    return if state.player.requested_action_at > Kernel.tick_count

    player_action = state.player.action
    player_action_at = state.player.action_at

    # first attack
    if state.player.requested_action == :attack
      if player_action == :standing
        state.player.next_action_queue.clear
        state.player.next_action_queue[Kernel.tick_count] = :slash_0
        state.player.next_action_queue[Kernel.tick_count + state.actions_lookup.slash_0.duration] = :standing
      else
        current_action = state.actions_lookup[state.player.action]
        state.player.next_action_queue.clear
        queue_at = player_action_at + current_action.interrupt_duration
        queue_at = Kernel.tick_count if queue_at < Kernel.tick_count
        next_action = current_action.next_action
        next_action ||= { name: :standing,
                          duration: 4 }
        if next_action
        state.player.next_action_queue[queue_at] = next_action.name
        state.player.next_action_queue[player_action_at +
                                       current_action.interrupt_duration +
                                       next_action.duration] = :standing
        end
      end
    end

    state.player.requested_action = nil
    state.player.requested_action_at = nil
  end

  def calc_sabre
    can_throw_sabre = true
    sabre_throws = [:throw_0, :throw_1, :throw_2]
    if !sabre_throws.include? state.player.action
      state.sabre.facing = nil
      state.sabre.is_active = false
      return
    end

    current_action = state.actions_lookup[state.player.action]
    throw_at = state.player.action_at + (current_action.throw_frame) * 5
    catch_at = state.player.action_at + (current_action.catch_frame) * 5
    if !Kernel.tick_count.between? throw_at, catch_at
      state.sabre.facing = nil
      state.sabre.is_active = false
      return
    end

    state.sabre.facing ||= state.player.facing

    state.sabre.is_active = true

    spline = [
      [  0, 0.25, 0.75, 1.0],
      [1.0, 0.75, 0.25,   0]
    ]

    throw_duration = catch_at - throw_at

    current_progress = args.easing.ease_spline throw_at,
                                               Kernel.tick_count,
                                               throw_duration,
                                               spline

    farthest_sabre_x = 32
    state.sabre.y = state.player.y
    state.sabre.x = state.player.x + farthest_sabre_x * current_progress * state.sabre.facing
  end

  def calc_next_action
    return if !state.player.next_action_queue[Kernel.tick_count]

    state.player.previous_action = state.player.action
    state.player.previous_action_at = state.player.action_at
    state.player.previous_action_ended_at = Kernel.tick_count
    state.player.action = state.player.next_action_queue[Kernel.tick_count]
    state.player.action_at = Kernel.tick_count

    is_air_born = state.player.y != 0

    if state.player.action == :slash_0
      state.player.dy = 0 if state.player.dy > 0
      if is_air_born
        state.player.dy  = 0.5
      else
        state.player.dx += 0.25 * state.player.facing
      end
    elsif state.player.action == :slash_1
      state.player.dy = 0 if state.player.dy > 0
      if is_air_born
        state.player.dy  = 0.5
      else
        state.player.dx += 0.25 * state.player.facing
      end
    elsif state.player.action == :throw_0
      if is_air_born
        state.player.dy  = 1.0
      end

      state.player.dx += 0.5 * state.player.facing
    elsif state.player.action == :throw_1
      if is_air_born
        state.player.dy  = 1.0
      end

      state.player.dx += 0.5 * state.player.facing
    elsif state.player.action == :throw_2
      if is_air_born
        state.player.dy  = 1.0
      end

      state.player.dx += 0.5 * state.player.facing
    elsif state.player.action == :slash_5
      state.player.dy = 0 if state.player.dy < 0
      if is_air_born
        state.player.dy += 1.0
      else
        state.player.dy += 1.0
      end

      state.player.dx += 1.0 * state.player.facing
    elsif state.player.action == :slash_6
      state.player.dy = 0 if state.player.dy > 0
      if is_air_born
        state.player.dy  = -0.5
      end

      state.player.dx += 0.5 * state.player.facing
    end
  end

  def tick
    defaults
    calc
    render
  end
end

$game = Game.new

def tick args
  $game.args = args
  $game.tick
end

$gtk.reset

Color And Rotation - main.rb link

# ./samples/03_rendering_sprites/04_color_and_rotation/app/main.rb
=begin
 APIs listing that haven't been encountered in previous sample apps:

 - merge: Returns a hash containing the contents of two original hashes.
   Merge does not allow duplicate keys, so the value of a repeated key
   will be overwritten.

   For example, if we had two hashes
   h1 = { "a" => 1, "b" => 2}
   h2 = { "b" => 3, "c" => 3}
   and we called the command
   h1.merge(h2)
   the result would the following hash
   { "a" => 1, "b" => 3, "c" => 3}.

 Reminders:

 - Hashes: Collection of unique keys and their corresponding values. The value can be found
   using their keys.
   In this sample app, we're using a hash to create a sprite.

 - args.outputs.sprites: An array. The values generate a sprite.
   The parameters are [X, Y, WIDTH, HEIGHT, PATH, ANGLE, ALPHA, RED, GREEN, BLUE]
   Before continuing with this sample app, it is HIGHLY recommended that you look
   at mygame/documentation/05-sprites.md.

 - args.inputs.keyboard.key_held.KEY: Determines if a key is being pressed.
   For more information about the keyboard, go to mygame/documentation/06-keyboard.md.

 - args.inputs.controller_one: Takes input from the controller based on what key is pressed.
   For more information about the controller, go to mygame/documentation/08-controllers.md.

 - num1.lesser(num2): Finds the lower value of the given options.

=end

# This sample app shows a car moving across the screen. It loops back around if it exceeds the dimensions of the screen,
# and also can be moved in different directions through keyboard input from the user.

# Calls the methods necessary for the game to run successfully.
def tick args
  default args
  render args.grid, args.outputs, args.state
  calc args.state
  process_inputs args
end

# Sets default values for the car sprite
# Initialization ||= only happens in the first frame
def default args
  args.state.sprite.width    = 19
  args.state.sprite.height   = 10
  args.state.sprite.scale    = 4
  args.state.max_speed       = 5
  args.state.x             ||= 100
  args.state.y             ||= 100
  args.state.speed         ||= 1
  args.state.angle         ||= 0
end

# Outputs sprite onto screen
def render grid, outputs, state
  outputs.background_color = [70, 70, 70]
  outputs.sprites <<  { **destination_rect(state), # sets first four parameters of car sprite
                        path: 'sprites/86.png',    # image path of car
                        angle: state.angle,
                        a: opacity,                # alpha
                        **saturation,
                        **source_rect(state),      # sprite sub division/tile (source x, y, w, h)
                        flip_horizontally: false,
                        flip_vertically: false,    # don't flip sprites
                        **rotation_anchor }
end

# Calls the calc_pos and calc_wrap methods.
def calc state
  calc_pos state
  calc_wrap state
end

# Changes sprite's position on screen
# Vectors have magnitude and direction, so the incremented x and y values give the car direction
def calc_pos state
  state.x     += state.angle.vector_x * state.speed # increments x by product of angle's x vector and speed
  state.y     += state.angle.vector_y * state.speed # increments y by product of angle's y vector and speed
  state.speed *= 1.1 # scales speed up
  state.speed  = state.speed.lesser(state.max_speed) # speed is either current speed or max speed, whichever has a lesser value (ensures that the car doesn't go too fast or exceed the max speed)
end

# The screen's dimensions are 1280x720. If the car goes out of scope,
# it loops back around on the screen.
def calc_wrap state

  # car returns to left side of screen if it disappears on right side of screen
  # sprite.width refers to tile's size, which is multipled by scale (4) to make it bigger
  state.x = -state.sprite.width * state.sprite.scale if state.x - 20 > 1280

  # car wraps around to right side of screen if it disappears on the left side
  state.x = 1280 if state.x + state.sprite.width * state.sprite.scale + 20 < 0

  # car wraps around to bottom of screen if it disappears at the top of the screen
  # if you subtract 520 pixels instead of 20 pixels, the car takes longer to reappear (try it!)
  state.y = 0    if state.y - 20 > 720 # if 20 pixels less than car's y position is greater than vertical scope

  # car wraps around to top of screen if it disappears at the bottom of the screen
  state.y = 720  if state.y + state.sprite.height * state.sprite.scale + 20 < 0
end

# Changes angle of sprite based on user input from keyboard or controller
def process_inputs args

  # NOTE: increasing the angle doesn't mean that the car will continue to go
  # in a specific direction. The angle is increasing, which means that if the
  # left key was kept in the "down" state, the change in the angle would cause
  # the car to go in a counter-clockwise direction and form a circle (360 degrees)
  if args.inputs.keyboard.key_held.left # if left key is pressed
    args.state.angle += 2 # car's angle is incremented by 2

  # The same applies to decreasing the angle. If the right key was kept in the
  # "down" state, the decreasing angle would cause the car to go in a clockwise
  # direction and form a circle (360 degrees)
  elsif args.inputs.keyboard.key_held.right # if right key is pressed
    args.state.angle -= 2 # car's angle is decremented by 2

  # Input from a controller can also change the angle of the car
  elsif args.inputs.controller_one.left_analog_x_perc != 0
    args.state.angle += 2 * args.inputs.controller_one.left_analog_x_perc * -1
  end
end

# A sprite's center of rotation can be altered
# Increasing either of these numbers would dramatically increase the
# car's drift when it turns!
def rotation_anchor
  { angle_anchor_x: 0.7, angle_anchor_y: 0.5 }
end

# Sets opacity value of sprite to 255 so that it is not transparent at all
# Change it to 0 and you won't be able to see the car sprite on the screen
def opacity
  255
end

# Sets the color of the sprite to white.
def saturation
  { r: 255, g: 255, b: 255 }
end

# Sets definition of destination_rect (used to define the car sprite)
def destination_rect state
  { x: state.x,
    y: state.y,
    w: state.sprite.width  * state.sprite.scale, # multiplies by 4 to set size
    h: state.sprite.height * state.sprite.scale }
end

# Portion of a sprite (a tile)
# Sub division of sprite is denoted as a rectangle directly related to original size of .png
# Tile is located at bottom left corner within a 19x10 pixel rectangle (based on sprite.width, sprite.height)
def source_rect state
  { source_x: 0,
    source_y: 0,
    source_w: state.sprite.width,
    source_h: state.sprite.height }
end

Particles - main.rb link

# ./samples/03_rendering_sprites/05_particles/app/main.rb
def tick args
  # Set the background color to black
  args.outputs.background_color = [0, 0, 0]

  # Initialize the particle queue if it doesn't exist
  args.state.particle_queue ||= []

  # Add a new particle to the queue if the mouse is clicked
  if args.inputs.mouse.click || args.inputs.mouse.held
    args.state.particle_queue << {
      x: args.inputs.mouse.x,    # Set the x position to the mouse's x position
      y: args.inputs.mouse.y,    # Set the y position to the mouse's y position
      emission_speed: 5,         # Set the emission speed to 5
      emission_angle: rand(360), # Set the emission angle to a random angle
      r: 128,                    # Set the red color to 128
      g: rand(128) + 128,        # Set the green color to a random value between 128 and 255
      b: rand(128) + 128,        # Set the blue color to a random value between 128 and 255
    }
  end

  # Update the particles
  args.state.particle_queue.each do |particle|
    # initialize default values for particle
    particle.a ||= 255
    particle.path ||= :solid
    particle.w ||= 5
    particle.h ||= 5
    particle.anchor_x ||= 0.5
    particle.anchor_y ||= 0.5

    # initialize dx and dy of particle based on the emission speed and angle
    particle.dx ||= particle.emission_speed * particle.emission_angle.vector_x
    particle.dy ||= particle.emission_speed * particle.emission_angle.vector_y

    # update the particle's position based on the dx and dy
    particle.x += particle.dx
    particle.y += particle.dy

    # decrease the speed of the particle
    particle.dx *= 0.95
    particle.dy *= 0.95

    # if the particle's speed is less than 1.0, decrease the alpha value
    if particle.dx.abs < 1.0 && particle.dy.abs < 1.0
      particle.a -= 5
    end
  end

  # Remove particles with an alpha value less than or equal to 0
  args.state.particle_queue.reject! do |particle|
    particle.a <= 0
  end

  args.outputs.labels << {
    x: 640,
    y: 720,
    text: "Click and hold the mouse to create particles.",
    r: 255,
    g: 255,
    b: 255,
    anchor_x: 0.5,
    anchor_y: 1.0,
  }

  # Render the particles
  args.outputs.primitives << args.state.particle_queue
end

GTK.reset

Physics And Collisions link

Simple - main.rb link

# ./samples/04_physics_and_collisions/01_simple/app/main.rb
=begin

 Reminders:
 - ARRAY#intersect_rect?: Returns true or false depending on if the two rectangles intersect.

 - args.outputs.solids: An array. The values generate a solid.
   The parameters are [X, Y, WIDTH, HEIGHT, RED, GREEN, BLUE]

=end

# This sample app shows collisions between two boxes.

# Runs methods needed for game to run properly.
def tick args
  tick_instructions args, "Sample app shows how to move a square over time and determine collision."
  defaults args
  render args
  calc args
end

# Sets default values.
def defaults args
  # These values represent the moving box.
  args.state.moving_box_speed   = 10
  args.state.moving_box_size    = 100
  args.state.moving_box_dx    ||=  1
  args.state.moving_box_dy    ||=  1
  args.state.moving_box       ||= [0, 0, args.state.moving_box_size, args.state.moving_box_size] # moving_box_size is set as the width and height

  # These values represent the center box.
  args.state.center_box ||= [540, 260, 200, 200, 180]
  args.state.center_box_collision ||= false # initially no collision
end

def render args
  # If the game state denotes that a collision has occured,
  # render a solid square, otherwise render a border instead.
  if args.state.center_box_collision
    args.outputs.solids << args.state.center_box
  else
    args.outputs.borders << args.state.center_box
  end

  # Then render the moving box.
  args.outputs.solids << args.state.moving_box
end

# Generally in a pipeline for a game engine, you have rendering,
# game simulation (calculation), and input processing.
# This fuction represents the game simulation.
def calc args
  position_moving_box args
  determine_collision_center_box args
end

# Changes the position of the moving box on the screen by multiplying the change in x (dx) and change in y (dy) by the speed,
# and adding it to the current position.
# dx and dy are positive if the box is moving right and up, respectively
# dx and dy are negative if the box is moving left and down, respectively
def position_moving_box args
  args.state.moving_box.x += args.state.moving_box_dx * args.state.moving_box_speed
  args.state.moving_box.y += args.state.moving_box_dy * args.state.moving_box_speed

  # 1280x720 are the virtual pixels you work with (essentially 720p).
  screen_width  = 1280
  screen_height = 720

  # Position of the box is denoted by the bottom left hand corner, in
  # that case, we have to subtract the width of the box so that it stays
  # in the scene (you can try deleting the subtraction to see how it
  # impacts the box's movement).
  if args.state.moving_box.x > screen_width - args.state.moving_box_size
    args.state.moving_box_dx = -1 # moves left
  elsif args.state.moving_box.x < 0
    args.state.moving_box_dx =  1 # moves right
  end

  # Here, we're making sure the moving box remains within the vertical scope of the screen
  if args.state.moving_box.y > screen_height - args.state.moving_box_size # if the box moves too high
    args.state.moving_box_dy = -1 # moves down
  elsif args.state.moving_box.y < 0 # if the box moves too low
    args.state.moving_box_dy =  1 # moves up
  end
end

def determine_collision_center_box args
  # Collision is handled by the engine. You simply have to call the
  # `intersect_rect?` function.
  if args.state.moving_box.intersect_rect? args.state.center_box # if the two boxes intersect
    args.state.center_box_collision = true # then a collision happened
  else
    args.state.center_box_collision = false # otherwise, no collision happened
  end
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Simple Aabb Collision - main.rb link

# ./samples/04_physics_and_collisions/01_simple_aabb_collision/app/main.rb
def tick args
  # define terrain of 32x32 sized squares
  args.state.terrain ||= [
    { x: 640,          y: 360,          w: 32, h: 32, path: 'sprites/square/blue.png' },
    { x: 640,          y: 360 - 32,     w: 32, h: 32, path: 'sprites/square/blue.png' },
    { x: 640,          y: 360 - 32 * 2, w: 32, h: 32, path: 'sprites/square/blue.png' },
    { x: 640 + 32,     y: 360 - 32 * 2, w: 32, h: 32, path: 'sprites/square/blue.png' },
    { x: 640 + 32 * 2, y: 360 - 32 * 2, w: 32, h: 32, path: 'sprites/square/blue.png' },
  ]

  # define player
  args.state.player ||= {
    x: 600,
    y: 360,
    w: 32,
    h: 32,
    dx: 0,
    dy: 0,
    path: 'sprites/square/red.png'
  }

  # render terrain and player
  args.outputs.sprites << args.state.terrain
  args.outputs.sprites << args.state.player

  # set dx and dy based on inputs
  args.state.player.dx = args.inputs.left_right * 2
  args.state.player.dy = args.inputs.up_down * 2

  # check for collisions on the x and y axis independently

  # increment the player's position by dx
  args.state.player.x += args.state.player.dx

  # check for collision on the x axis first
  collision = args.state.terrain.find { |t| t.intersect_rect? args.state.player }

  # if there is a collision, move the player to the edge of the collision
  # based on the direction of the player's movement and set the player's
  # dx to 0
  if collision
    if args.state.player.dx > 0
      args.state.player.x = collision.x - args.state.player.w
    elsif args.state.player.dx < 0
      args.state.player.x = collision.x + collision.w
    end
    args.state.player.dx = 0
  end

  # increment the player's position by dy
  args.state.player.y += args.state.player.dy

  # check for collision on the y axis next
  collision = args.state.terrain.find { |t| t.intersect_rect? args.state.player }

  # if there is a collision, move the player to the edge of the collision
  # based on the direction of the player's movement and set the player's
  # dy to 0
  if collision
    if args.state.player.dy > 0
      args.state.player.y = collision.y - args.state.player.h
    elsif args.state.player.dy < 0
      args.state.player.y = collision.y + collision.h
    end
    args.state.player.dy = 0
  end
end

Simple Aabb Collision With Map Editor - main.rb link

# ./samples/04_physics_and_collisions/01_simple_aabb_collision_with_map_editor/app/main.rb
# the sample app is an expansion of ./01_simple_aabb_collision
# but includes an in game map editor that saves map data to disk
def tick args
  # if it's the first tick, read the terrain data from disk
  # and create the player
  if Kernel.tick_count == 0
    args.state.terrain = read_terrain_data args

    args.state.player = {
      x: 320,
      y: 320,
      w: 32,
      h: 32,
      dx: 0,
      dy: 0,
      path: 'sprites/square/red.png'
    }
  end

  # tick the game (where input and aabb collision is processed)
  tick_game args

  # tick the map editor
  tick_map_editor args
end

def tick_game args
  # render terrain and player
  args.outputs.sprites << args.state.terrain
  args.outputs.sprites << args.state.player

  # set dx and dy based on inputs
  args.state.player.dx = args.inputs.left_right * 2
  args.state.player.dy = args.inputs.up_down * 2

  # check for collisions on the x and y axis independently

  # increment the player's position by dx
  args.state.player.x += args.state.player.dx

  # check for collision on the x axis first
  collision = args.state.terrain.find { |t| t.intersect_rect? args.state.player }

  # if there is a collision, move the player to the edge of the collision
  # based on the direction of the player's movement and set the player's
  # dx to 0
  if collision
    if args.state.player.dx > 0
      args.state.player.x = collision.x - args.state.player.w
    elsif args.state.player.dx < 0
      args.state.player.x = collision.x + collision.w
    end
    args.state.player.dx = 0
  end

  # increment the player's position by dy
  args.state.player.y += args.state.player.dy

  # check for collision on the y axis next
  collision = args.state.terrain.find { |t| t.intersect_rect? args.state.player }

  # if there is a collision, move the player to the edge of the collision
  # based on the direction of the player's movement and set the player's
  # dy to 0
  if collision
    if args.state.player.dy > 0
      args.state.player.y = collision.y - args.state.player.h
    elsif args.state.player.dy < 0
      args.state.player.y = collision.y + collision.h
    end
    args.state.player.dy = 0
  end
end

def tick_map_editor args
  # determine the location of the mouse, but
  # aligned to the grid
  grid_aligned_mouse_rect = {
    x: args.inputs.mouse.x.idiv(32) * 32,
    y: args.inputs.mouse.y.idiv(32) * 32,
    w: 32,
    h: 32
  }

  # determine if there's a tile at the grid aligned mouse location
  existing_terrain = args.state.terrain.find { |t| t.intersect_rect? grid_aligned_mouse_rect }

  # if there is, then render a red square to denote that
  # the tile will be deleted
  if existing_terrain
    args.outputs.sprites << {
      x: args.inputs.mouse.x.idiv(32) * 32,
      y: args.inputs.mouse.y.idiv(32) * 32,
      w: 32,
      h: 32,
      path: "sprites/square/red.png",
      a: 128
    }
  else
    # otherwise, render a blue square to denote that
    # a tile will be added
    args.outputs.sprites << {
      x: args.inputs.mouse.x.idiv(32) * 32,
      y: args.inputs.mouse.y.idiv(32) * 32,
      w: 32,
      h: 32,
      path: "sprites/square/blue.png",
      a: 128
    }
  end

  # if the mouse is clicked, then add or remove a tile
  if args.inputs.mouse.click
    if existing_terrain
      args.state.terrain.delete existing_terrain
    else
      args.state.terrain << { **grid_aligned_mouse_rect, path: "sprites/square/blue.png" }
    end

    # once the terrain state has been updated
    # save the terrain data to disk
    write_terrain_data args
  end
end

def read_terrain_data args
  # create the terrain data file if it doesn't exist
  contents = args.gtk.read_file "data/terrain.txt"
  if !contents
    args.gtk.write_file "data/terrain.txt", ""
  end

  # read the terrain data from disk which is a csv
  args.gtk.read_file('data/terrain.txt').split("\n").map do |line|
    x, y, w, h = line.split(',').map(&:to_i)
    { x: x, y: y, w: w, h: h, path: 'sprites/square/blue.png' }
  end
end

def write_terrain_data args
  terrain_csv = args.state.terrain.map { |t| "#{t.x},#{t.y},#{t.w},#{t.h}" }.join "\n"
  args.gtk.write_file 'data/terrain.txt', terrain_csv
end

Simple Aabb Collision With Map Editor - Data - terrain.txt link

# ./samples/04_physics_and_collisions/01_simple_aabb_collision_with_map_editor/data/terrain.txt
352,320,32,32
352,352,32,32
352,384,32,32
352,256,32,32
352,192,32,32
352,224,32,32

Moving Objects - main.rb link

# ./samples/04_physics_and_collisions/02_moving_objects/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - Hashes: Collection of unique keys and their corresponding values. The value can be found
   using their keys.

   For example, if we have a "numbers" hash that stores numbers in English as the
   key and numbers in Spanish as the value, we'd have a hash that looks like this...
   numbers = { "one" => "uno", "two" => "dos", "three" => "tres" }
   and on it goes.

   Now if we wanted to find the corresponding value of the "one" key, we could say
   puts numbers["one"]
   which would print "uno" to the console.

 - num1.greater(num2): Returns the greater value.
   For example, if we have the command
   puts 4.greater(3)
   the number 4 would be printed to the console since it has a greater value than 3.
   Similar to lesser, which returns the lesser value.

 - num1.lesser(num2): Finds the lower value of the given options.
   For example, in the statement
   a = 4.lesser(3)
   3 has a lower value than 4, which means that the value of a would be set to 3,
   but if the statement had been
   a = 4.lesser(5)
   4 has a lower value than 5, which means that the value of a would be set to 4.

 - reject: Removes elements from a collection if they meet certain requirements.
   For example, you can derive an array of odd numbers from an original array of
   numbers 1 through 10 by rejecting all elements that are even (or divisible by 2).

 - find_all: Finds all values that satisfy specific requirements.
   For example, you can find all elements of a collection that are divisible by 2
   or find all objects that have intersected with another object.

 - abs: Returns the absolute value.
   For example, the command
   (-30).abs
   would return 30 as a result.

 - map: Ruby method used to transform data; used in arrays, hashes, and collections.
   Can be used to perform an action on every element of a collection, such as multiplying
   each element by 2 or declaring every element as a new entity.

 Reminders:

 - args.inputs.keyboard.KEY: Determines if a key has been pressed.
   For more information about the keyboard, take a look at mygame/documentation/06-keyboard.md.

 - ARRAY#intersect_rect?: Returns true or false depending on if the two rectangles intersect.

 - args.outputs.solids: An array. The values generate a solid.
   The parameters are [X, Y, WIDTH, HEIGHT, RED, GREEN, BLUE]
   For more information about solids, go to mygame/documentation/03-solids-and-borders.md.

=end

# Calls methods needed for game to run properly
def tick args
  tick_instructions args, "Use LEFT and RIGHT arrow keys to move and SPACE to jump."
  defaults args
  render args
  calc args
  input args
end

# sets default values and creates empty collections
# initialization only happens in the first frame
def defaults args
  fiddle args
  args.state.enemy.hammers ||= []
  args.state.enemy.hammer_queue ||= []
  Kernel.tick_count = Kernel.tick_count
  args.state.bridge_top = 128
  args.state.player.x  ||= 0                        # initializes player's properties
  args.state.player.y  ||= args.state.bridge_top
  args.state.player.w  ||= 64
  args.state.player.h  ||= 64
  args.state.player.dy ||= 0
  args.state.player.dx ||= 0
  args.state.enemy.x   ||= 800                      # initializes enemy's properties
  args.state.enemy.y   ||= 0
  args.state.enemy.w   ||= 128
  args.state.enemy.h   ||= 128
  args.state.enemy.dy  ||= 0
  args.state.enemy.dx  ||= 0
  args.state.game_over_at ||= 0
end

# sets enemy, player, hammer values
def fiddle args
  args.state.gravity                     = -0.3
  args.state.enemy_jump_power            = 10       # sets enemy values
  args.state.enemy_jump_interval         = 60
  args.state.hammer_throw_interval       = 40       # sets hammer values
  args.state.hammer_launch_power_default = 5
  args.state.hammer_launch_power_near    = 2
  args.state.hammer_launch_power_far     = 7
  args.state.hammer_upward_launch_power  = 15
  args.state.max_hammers_per_volley      = 10
  args.state.gap_between_hammers         = 10
  args.state.player_jump_power           = 10       # sets player values
  args.state.player_jump_power_duration  = 10
  args.state.player_max_run_speed        = 10
  args.state.player_speed_slowdown_rate  = 0.9
  args.state.player_acceleration         = 1
  args.state.hammer_size                 = 32
end

# outputs objects onto the screen
def render args
  args.outputs.solids << 20.map_with_index do |i| # uses 20 squares to form bridge
    # sets x by multiplying 64 to index to find pixel value (places all squares side by side)
    # subtracts 64 from bridge_top because position is denoted by bottom left corner
    [i * 64, args.state.bridge_top - 64, 64, 64]
  end

  args.outputs.solids << [args.state.x, args.state.y, args.state.w, args.state.h, 255, 0, 0]
  args.outputs.solids << [args.state.player.x, args.state.player.y, args.state.player.w, args.state.player.h, 255, 0, 0] # outputs player onto screen (red box)
  args.outputs.solids << [args.state.enemy.x, args.state.enemy.y, args.state.enemy.w, args.state.enemy.h, 0, 255, 0] # outputs enemy onto screen (green box)
  args.outputs.solids << args.state.enemy.hammers # outputs enemy's hammers onto screen
end

# Performs calculations to move objects on the screen
def calc args

  # Since velocity is the change in position, the change in x increases by dx. Same with y and dy.
  args.state.player.x  += args.state.player.dx
  args.state.player.y  += args.state.player.dy

  # Since acceleration is the change in velocity, the change in y (dy) increases every frame
  args.state.player.dy += args.state.gravity

  # player's y position is either current y position or y position of top of
  # bridge, whichever has a greater value
  # ensures that the player never goes below the bridge
  args.state.player.y  = args.state.player.y.greater(args.state.bridge_top)

  # player's x position is either the current x position or 0, whichever has a greater value
  # ensures that the player doesn't go too far left (out of the screen's scope)
  args.state.player.x  = args.state.player.x.greater(0)

  # player is not falling if it is located on the top of the bridge
  args.state.player.falling = false if args.state.player.y == args.state.bridge_top
  args.state.player.rect = [args.state.player.x, args.state.player.y, args.state.player.h, args.state.player.w] # sets definition for player

  args.state.enemy.x += args.state.enemy.dx # velocity; change in x increases by dx
  args.state.enemy.y += args.state.enemy.dy # same with y and dy

  # ensures that the enemy never goes below the bridge
  args.state.enemy.y  = args.state.enemy.y.greater(args.state.bridge_top)

  # ensures that the enemy never goes too far left (outside the screen's scope)
  args.state.enemy.x  = args.state.enemy.x.greater(0)

  # objects that go up must come down because of gravity
  args.state.enemy.dy += args.state.gravity

  args.state.enemy.y  = args.state.enemy.y.greater(args.state.bridge_top)

  #sets definition of enemy
  args.state.enemy.rect = [args.state.enemy.x, args.state.enemy.y, args.state.enemy.h, args.state.enemy.w]

  if args.state.enemy.y == args.state.bridge_top # if enemy is located on the top of the bridge
    args.state.enemy.dy = 0 # there is no change in y
  end

  # if 60 frames have passed and the enemy is not moving vertically
  if Kernel.tick_count.mod_zero?(args.state.enemy_jump_interval) && args.state.enemy.dy == 0
    args.state.enemy.dy = args.state.enemy_jump_power # the enemy jumps up
  end

  # if 40 frames have passed or 5 frames have passed since the game ended
  if Kernel.tick_count.mod_zero?(args.state.hammer_throw_interval) || args.state.game_over_at.elapsed_time == 5
    # rand will return a number greater than or equal to 0 and less than given variable's value (since max is excluded)
    # that is why we're adding 1, to include the max possibility
    volley_dx   = (rand(args.state.hammer_launch_power_default) + 1) * -1 # horizontal movement (follow order of operations)

    # if the horizontal distance between the player and enemy is less than 128 pixels
    if (args.state.player.x - args.state.enemy.x).abs < 128
      # the change in x won't be that great since the enemy and player are closer to each other
      volley_dx = (rand(args.state.hammer_launch_power_near) + 1) * -1
    end

    # if the horizontal distance between the player and enemy is greater than 300 pixels
    if (args.state.player.x - args.state.enemy.x).abs > 300
      # change in x will be more drastic since player and enemy are so far apart
      volley_dx = (rand(args.state.hammer_launch_power_far) + 1) * -1 # more drastic change
    end

    (rand(args.state.max_hammers_per_volley) + 1).map_with_index do |i|
      args.state.enemy.hammer_queue << { # stores hammer values in a hash
        x: args.state.enemy.x,
        w: args.state.hammer_size,
        h: args.state.hammer_size,
        dx: volley_dx, # change in horizontal position
        # multiplication operator takes precedence over addition operator
        throw_at: Kernel.tick_count + i * args.state.gap_between_hammers
      }
    end
  end

  # add elements from hammer_queue collection to the hammers collection by
  # finding all hammers that were thrown before the current frame (have already been thrown)
  args.state.enemy.hammers += args.state.enemy.hammer_queue.find_all do |h|
    h[:throw_at] < Kernel.tick_count
  end

  args.state.enemy.hammers.each do |h| # sets values for all hammers in collection
    h[:y]  ||= args.state.enemy.y + 130
    h[:dy] ||= args.state.hammer_upward_launch_power
    h[:dy]  += args.state.gravity # acceleration is change in gravity
    h[:x]   += h[:dx] # incremented by change in position
    h[:y]   += h[:dy]
    h[:rect] = [h[:x], h[:y], h[:w], h[:h]] # sets definition of hammer's rect
  end

  # reject hammers that have been thrown before current frame (have already been thrown)
  args.state.enemy.hammer_queue = args.state.enemy.hammer_queue.reject do |h|
    h[:throw_at] < Kernel.tick_count
  end

  # any hammers with a y position less than 0 are rejected from the hammers collection
  # since they have gone too far down (outside the scope's screen)
  args.state.enemy.hammers = args.state.enemy.hammers.reject { |h| h[:y] < 0 }

  # if there are any hammers that intersect with (or hit) the player,
  # the reset_player method is called (so the game can start over)
  if args.state.enemy.hammers.any? { |h| h[:rect].intersect_rect?(args.state.player.rect) }
    reset_player args
  end

  # if the enemy's rect intersects with (or hits) the player,
  # the reset_player method is called (so the game can start over)
  if args.state.enemy.rect.intersect_rect? args.state.player.rect
    reset_player args
  end
end

# Resets the player by changing its properties back to the values they had at initialization
def reset_player args
  args.state.player.x = 0
  args.state.player.y = args.state.bridge_top
  args.state.player.dy = 0
  args.state.player.dx = 0
  args.state.enemy.hammers.clear # empties hammer collection
  args.state.enemy.hammer_queue.clear # empties hammer_queue
  args.state.game_over_at = Kernel.tick_count # game_over_at set to current frame (or passage of time)
end

# Processes input from the user to move the player
def input args
  if args.inputs.keyboard.space # if the user presses the space bar
    args.state.player.jumped_at ||= Kernel.tick_count # jumped_at is set to current frame

    # if the time that has passed since the jump is less than the player's jump duration and
    # the player is not falling
    if args.state.player.jumped_at.elapsed_time < args.state.player_jump_power_duration && !args.state.player.falling
      args.state.player.dy = args.state.player_jump_power # change in y is set to power of player's jump
    end
  end

  # if the space bar is in the "up" state (or not being pressed down)
  if args.inputs.keyboard.key_up.space
    args.state.player.jumped_at = nil # jumped_at is empty
    args.state.player.falling = true # the player is falling
  end

  if args.inputs.keyboard.left # if left key is pressed
    args.state.player.dx -= args.state.player_acceleration # dx decreases by acceleration (player goes left)
    # dx is either set to current dx or the negative max run speed (which would be -10),
    # whichever has a greater value
    args.state.player.dx = args.state.player.dx.greater(-args.state.player_max_run_speed)
  elsif args.inputs.keyboard.right # if right key is pressed
    args.state.player.dx += args.state.player_acceleration # dx increases by acceleration (player goes right)
    # dx is either set to current dx or max run speed (which would be 10),
    # whichever has a lesser value
    args.state.player.dx = args.state.player.dx.lesser(args.state.player_max_run_speed)
  else
    args.state.player.dx *= args.state.player_speed_slowdown_rate # dx is scaled down
  end
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.space ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Entities - main.rb link

# ./samples/04_physics_and_collisions/03_entities/app/main.rb
=begin

 Reminders:

 - map: Ruby method used to transform data; used in arrays, hashes, and collections.
   Can be used to perform an action on every element of a collection, such as multiplying
   each element by 2 or declaring every element as a new entity.

 - reject: Removes elements from a collection if they meet certain requirements.
   For example, you can derive an array of odd numbers from an original array of
   numbers 1 through 10 by rejecting all elements that are even (or divisible by 2).

 - args.state.new_entity: Used when we want to create a new object, like a sprite or button.
   In this sample app, new_entity is used to define the properties of enemies and bullets.
   (Remember, you can use state to define ANY property and it will be retained across frames.)

 - args.outputs.labels: An array. The values generate a label on the screen.
   The parameters are [X, Y, TEXT, SIZE, ALIGN, RED, GREEN, BLUE, ALPHA, FONT STYLE]

 - ARRAY#intersect_rect?: Returns true or false depending on if the two rectangles intersect.

 - args.inputs.mouse.click.point.(x|y): The x and y location of the mouse.

=end

# This sample app shows enemies that contain an id value and the time they were created.
# These enemies can be removed by shooting at them with bullets.

# Calls all methods necessary for the game to function properly.
def tick args
  tick_instructions args, "Sample app shows how to use args.state.new_entity along with collisions. CLICK to shoot a bullet."
  defaults args
  render args
  calc args
  process_inputs args
end

# Sets default values
# Enemies and bullets start off as empty collections
def defaults args
  args.state.enemies ||= []
  args.state.bullets ||= []
end

# Provides each enemy in enemies collection with rectangular border,
# as well as a label showing id and when they were created
def render args
  # When you're calling a method that takes no arguments, you can use this & syntax on map.
  # Numbers are being added to x and y in order to keep the text within the enemy's borders.
  args.outputs.borders << args.state.enemies.map(&:rect)
  args.outputs.labels  << args.state.enemies.flat_map do |enemy|
    [
      [enemy.x + 4, enemy.y + 29, "id: #{enemy.entity_id}", -3, 0],
      [enemy.x + 4, enemy.y + 17, "created_at: #{enemy.created_at}", -3, 0] # frame enemy was created
    ]
  end

  # Outputs bullets in bullets collection as rectangular solids
  args.outputs.solids << args.state.bullets.map(&:rect)
end

# Calls all methods necessary for performing calculations
def calc args
  add_new_enemies_if_needed args
  move_bullets args
  calculate_collisions args
  remove_bullets_of_screen args
end

# Adds enemies to the enemies collection and sets their values
def add_new_enemies_if_needed args
  return if args.state.enemies.length >= 10 # if 10 or more enemies, enemies are not added
  return unless args.state.bullets.length == 0 # if user has not yet shot bullet, no enemies are added

  args.state.enemies += (10 - args.state.enemies.length).map do # adds enemies so there are 10 total
    args.state.new_entity(:enemy) do |e| # each enemy is declared as a new entity
      e.x = 640 + 500 * rand # each enemy is given random position on screen
      e.y = 600 * rand + 50
      e.rect = [e.x, e.y, 130, 30] # sets definition for enemy's rect
    end
  end
end

# Moves bullets across screen
# Sets definition of the bullets
def move_bullets args
  args.state.bullets.each do |bullet| # perform action on each bullet in collection
    bullet.x += bullet.speed # increment x by speed (bullets fly horizontally across screen)

    # By randomizing the value that increments bullet.y, the bullet does not fly straight up and out
    # of the scope of the screen. Try removing what follows bullet.speed, or changing 0.25 to 1.25 to
    # see what happens to the bullet's movement.
    bullet.y += bullet.speed.*(0.25).randomize(:ratio, :sign)
    bullet.rect = [bullet.x, bullet.y, bullet.size, bullet.size] # sets definition of bullet's rect
  end
end

# Determines if a bullet hits an enemy
def calculate_collisions args
  args.state.bullets.each do |bullet| # perform action on every bullet and enemy in collections
    args.state.enemies.each do |enemy|
      # if bullet has not exploded yet and the bullet hits an enemy
      if !bullet.exploded && bullet.rect.intersect_rect?(enemy.rect)
        bullet.exploded = true # bullet explodes
        enemy.dead = true # enemy is killed
      end
    end
  end

  # All exploded bullets are rejected or removed from the bullets collection
  # and any dead enemy is rejected from the enemies collection.
  args.state.bullets = args.state.bullets.reject(&:exploded)
  args.state.enemies = args.state.enemies.reject(&:dead)
end

# Bullets are rejected from bullets collection once their position exceeds the width of screen
def remove_bullets_of_screen args
  args.state.bullets = args.state.bullets.reject { |bullet| bullet.x > 1280 } # screen width is 1280
end

# Calls fire_bullet method
def process_inputs args
  fire_bullet args
end

# Once mouse is clicked by the user to fire a bullet, a new bullet is added to bullets collection
def fire_bullet args
  return unless args.inputs.mouse.click # return unless mouse is clicked
  args.state.bullets << args.state.new_entity(:bullet) do |bullet| # new bullet is declared a new entity
    bullet.y = args.inputs.mouse.click.point.y # set to the y value of where the mouse was clicked
    bullet.x = 0 # starts on the left side of the screen
    bullet.size = 10
    bullet.speed = 10 * rand + 2 # speed of a bullet is randomized
    bullet.rect = [bullet.x, bullet.y, bullet.size, bullet.size] # definition is set
  end
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.space ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Box Collision - main.rb link

# ./samples/04_physics_and_collisions/04_box_collision/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - first: Returns the first element of the array.
   For example, if we have an array
   numbers = [1, 2, 3, 4, 5]
   and we call first by saying
   numbers.first
   the number 1 will be returned because it is the first element of the numbers array.

 - num1.idiv(num2): Divides two numbers and returns an integer.
   For example,
   16.idiv(3) = 5, because 16 / 3 is 5.33333 returned as an integer.
   16.idiv(4) = 4, because 16 / 4 is 4 and already has no decimal.

 Reminders:

 - find_all: Finds all values that satisfy specific requirements.

 - ARRAY#intersect_rect?: An array with at least four values is
   considered a rect. The intersect_rect? function returns true
   or false depending on if the two rectangles intersect.

 - reject: Removes elements from a collection if they meet certain requirements.

=end

# This sample app allows users to create tiles and place them anywhere on the screen as obstacles.
# The player can then move and maneuver around them.

class PoorManPlatformerPhysics
  attr_accessor :grid, :inputs, :state, :outputs

  # Calls all methods necessary for the app to run successfully.
  def tick
    defaults
    render
    calc
    process_inputs
  end

  # Sets default values for variables.
  # The ||= sign means that the variable will only be set to the value following the = sign if the value has
  # not already been set before. Intialization happens only in the first frame.
  def defaults
    state.tile_size               = 64
    state.gravity                 = -0.2
    state.previous_tile_size    ||= state.tile_size
    state.x                     ||= 0
    state.y                     ||= 800
    state.dy                    ||= 0
    state.dx                    ||= 0
    state.world                 ||= []
    state.world_lookup          ||= {}
    state.world_collision_rects ||= []
  end

  # Outputs solids and borders of different colors for the world and collision_rects collections.
  def render

    # Sets a black background on the screen (Comment this line out and the background will become white.)
    # Also note that black is the default color for when no color is assigned.
    outputs.solids << grid.rect

    # The position, size, and color (white) are set for borders given to the world collection.
    # Try changing the color by assigning different numbers (between 0 and 255) to the last three parameters.
    outputs.borders << state.world.map do |x, y|
      [x * state.tile_size,
       y * state.tile_size,
       state.tile_size,
       state.tile_size, 255, 255, 255]
    end

    # The top, bottom, and sides of the borders for collision_rects are different colors.
    outputs.borders << state.world_collision_rects.map do |e|
      [
        [e[:top],                             0, 170,   0], # top is a shade of green
        [e[:bottom],                          0, 100, 170], # bottom is a shade of greenish-blue
        [e[:left_right],                    170,   0,   0], # left and right are a shade of red
      ]
    end

    # Sets the position, size, and color (a shade of green) of the borders of only the player's
    # box and outputs it. If you change the 180 to 0, the player's box will be black and you
    # won't be able to see it (because it will match the black background).
    outputs.borders << [state.x,
                        state.y,
                        state.tile_size,
                        state.tile_size,  0, 180, 0]
  end

  # Calls methods needed to perform calculations.
  def calc
    calc_world_lookup
    calc_player
  end

  # Performs calculations on world_lookup and sets values.
  def calc_world_lookup

    # If the tile size isn't equal to the previous tile size,
    # the previous tile size is set to the tile size,
    # and world_lookup hash is set to empty.
    if state.tile_size != state.previous_tile_size
      state.previous_tile_size = state.tile_size
      state.world_lookup = {} # empty hash
    end

    # return if the world_lookup hash has keys (or, in other words, is not empty)
    # return unless the world collection has values inside of it (or is not empty)
    return if state.world_lookup.keys.length > 0
    return unless state.world.length > 0

    # Starts with an empty hash for world_lookup.
    # Searches through the world and finds the coordinates that exist.
    state.world_lookup = {}
    state.world.each { |x, y| state.world_lookup[[x, y]] = true }

    # Assigns world_collision_rects for every sprite drawn.
    state.world_collision_rects =
      state.world_lookup
          .keys
          .map do |coord_x, coord_y|
            s = state.tile_size
            # multiply by tile size so the grid coordinates; sets pixel value
            # don't forget that position is denoted by bottom left corner
            # set x = coord_x or y = coord_y and see what happens!
            x = s * coord_x
            y = s * coord_y
            {
              # The values added to x, y, and s position the world_collision_rects so they all appear
              # stacked (on top of world rects) but don't directly overlap.
              # Remove these added values and mess around with the rect placement!
              args:       [coord_x, coord_y],
              left_right: [x,     y + 4, s,     s - 6], # hash keys and values
              top:        [x + 4, y + 6, s - 8, s - 6],
              bottom:     [x + 1, y - 1, s - 2, s - 8],
            }
          end
  end

  # Performs calculations to change the x and y values of the player's box.
  def calc_player

    # Since acceleration is the change in velocity, the change in y (dy) increases every frame.
    # What goes up must come down because of gravity.
    state.dy += state.gravity

    # Calls the calc_box_collision and calc_edge_collision methods.
    calc_box_collision
    calc_edge_collision

    # Since velocity is the change in position, the change in y increases by dy. Same with x and dx.
    state.y += state.dy
    state.x += state.dx

    # Scales dx down.
    state.dx *= 0.8
  end

  # Calls methods needed to determine collisions between player and world_collision rects.
  def calc_box_collision
    return unless state.world_lookup.keys.length > 0 # return unless hash has atleast 1 key
    collision_floor!
    collision_left!
    collision_right!
    collision_ceiling!
  end

  # Finds collisions between the bottom of the player's rect and the top of a world_collision_rect.
  def collision_floor!
    return unless state.dy <= 0 # return unless player is going down or is as far down as possible
    player_rect = [state.x, state.y - 0.1, state.tile_size, state.tile_size] # definition of player

    # Goes through world_collision_rects to find all intersections between the bottom of player's rect and
    # the top of a world_collision_rect (hence the "-0.1" above)
    floor_collisions = state.world_collision_rects
                           .find_all { |r| r[:top].intersect_rect?(player_rect, collision_tollerance) }
                           .first

    return unless floor_collisions # return unless collision occurred
    state.y = floor_collisions[:top].top # player's y is set to the y of the top of the collided rect
    state.dy = 0 # if a collision occurred, the player's rect isn't moving because its path is blocked
  end

  # Finds collisions between the player's left side and the right side of a world_collision_rect.
  def collision_left!
    return unless state.dx < 0 # return unless player is moving left
    player_rect = [state.x - 0.1, state.y, state.tile_size, state.tile_size]

    # Goes through world_collision_rects to find all intersections beween the player's left side and the
    # right side of a world_collision_rect.
    left_side_collisions = state.world_collision_rects
                               .find_all { |r| r[:left_right].intersect_rect?(player_rect, collision_tollerance) }
                               .first

    return unless left_side_collisions # return unless collision occurred

    # player's x is set to the value of the x of the collided rect's right side
    state.x = left_side_collisions[:left_right].right
    state.dx = 0 # player isn't moving left because its path is blocked
  end

  # Finds collisions between the right side of the player and the left side of a world_collision_rect.
  def collision_right!
    return unless state.dx > 0 # return unless player is moving right
    player_rect = [state.x + 0.1, state.y, state.tile_size, state.tile_size]

    # Goes through world_collision_rects to find all intersections between the player's right side
    # and the left side of a world_collision_rect (hence the "+0.1" above)
    right_side_collisions = state.world_collision_rects
                                .find_all { |r| r[:left_right].intersect_rect?(player_rect, collision_tollerance) }
                                .first

    return unless right_side_collisions # return unless collision occurred

    # player's x is set to the value of the collided rect's left, minus the size of a rect
    # tile size is subtracted because player's position is denoted by bottom left corner
    state.x = right_side_collisions[:left_right].left - state.tile_size
    state.dx = 0 # player isn't moving right because its path is blocked
  end

  # Finds collisions between the top of the player's rect and the bottom of a world_collision_rect.
  def collision_ceiling!
    return unless state.dy > 0 # return unless player is moving up
    player_rect = [state.x, state.y + 0.1, state.tile_size, state.tile_size]

    # Goes through world_collision_rects to find intersections between the bottom of a
    # world_collision_rect and the top of the player's rect (hence the "+0.1" above)
    ceil_collisions = state.world_collision_rects
                          .find_all { |r| r[:bottom].intersect_rect?(player_rect, collision_tollerance) }
                          .first

    return unless ceil_collisions # return unless collision occurred

    # player's y is set to the bottom y of the rect it collided with, minus the size of a rect
    state.y = ceil_collisions[:bottom].y - state.tile_size
    state.dy = 0 # if a collision occurred, the player isn't moving up because its path is blocked
  end

  # Makes sure the player remains within the screen's dimensions.
  def calc_edge_collision

    #Ensures that the player doesn't fall below the map.
    if state.y < 0
      state.y = 0
      state.dy = 0

    #Ensures that the player doesn't go too high.
    # Position of player is denoted by bottom left hand corner, which is why we have to subtract the
    # size of the player's box (so it remains visible on the screen)
    elsif state.y > 720 - state.tile_size # if the player's y position exceeds the height of screen
      state.y = 720 - state.tile_size # the player will remain as high as possible while staying on screen
      state.dy = 0
    end

    # Ensures that the player remains in the horizontal range that it is supposed to.
    if state.x >= 1280 - state.tile_size && state.dx > 0 # if player moves too far right
      state.x = 1280 - state.tile_size # player will remain as right as possible while staying on screen
      state.dx = 0
    elsif state.x <= 0 && state.dx < 0 # if player moves too far left
      state.x = 0 # player will remain as left as possible while remaining on screen
      state.dx = 0
    end
  end

  # Processes input from the user on the keyboard.
  def process_inputs
    if inputs.mouse.down
      state.world_lookup = {}
      x, y = to_coord inputs.mouse.down.point  # gets x, y coordinates for the grid

      if state.world.any? { |loc| loc == [x, y] }  # checks if coordinates duplicate
        state.world = state.world.reject { |loc| loc == [x, y] }  # erases tile space
      else
        state.world << [x, y] # If no duplicates, adds to world collection
      end
    end

    # Sets dx to 0 if the player lets go of arrow keys.
    if inputs.keyboard.key_up.right
      state.dx = 0
    elsif inputs.keyboard.key_up.left
      state.dx = 0
    end

    # Sets dx to 3 in whatever direction the player chooses.
    if inputs.keyboard.key_held.right # if right key is pressed
      state.dx =  3
    elsif inputs.keyboard.key_held.left # if left key is pressed
      state.dx = -3
    end

    #Sets dy to 5 to make the player ~fly~ when they press the space bar
    if inputs.keyboard.key_held.space
      state.dy = 5
    end
  end

  def to_coord point

    # Integer divides (idiv) point.x to turn into grid
    # Then, you can just multiply each integer by state.tile_size later so the grid coordinates.
    [point.x.idiv(state.tile_size), point.y.idiv(state.tile_size)]
  end

  # Represents the tolerance for a collision between the player's rect and another rect.
  def collision_tollerance
    0.0
  end
end

$platformer_physics = PoorManPlatformerPhysics.new

def tick args
  $platformer_physics.grid    = args.grid
  $platformer_physics.inputs  = args.inputs
  $platformer_physics.state    = args.state
  $platformer_physics.outputs = args.outputs
  $platformer_physics.tick
  tick_instructions args, "Sample app shows platformer collisions. CLICK to place box. ARROW keys to move around. SPACE to jump."
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Box Collision 2 - main.rb link

# ./samples/04_physics_and_collisions/05_box_collision_2/app/main.rb
=begin
 APIs listing that haven't been encountered in previous sample apps:

 - times: Performs an action a specific number of times.
   For example, if we said
   5.times puts "Hello DragonRuby",
   then we'd see the words "Hello DragonRuby" printed on the console 5 times.

 - split: Divides a string into substrings based on a delimiter.
   For example, if we had a command
   "DragonRuby is awesome".split(" ")
   then the result would be
   ["DragonRuby", "is", "awesome"] because the words are separated by a space delimiter.

 - join: Opposite of split; converts each element of array to a string separated by delimiter.
   For example, if we had a command
   ["DragonRuby","is","awesome"].join(" ")
   then the result would be
   "DragonRuby is awesome".

 Reminders:

 - to_s: Returns a string representation of an object.
   For example, if we had
   500.to_s
   the string "500" would be returned.
   Similar to to_i, which returns an integer representation of an object.

 - elapsed_time: How many frames have passed since the click event.

 - args.outputs.labels: An array. Values in the array generate labels on the screen.
   The parameters are: [X, Y, TEXT, SIZE, ALIGN, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.

 - inputs.mouse.down: Determines whether or not the mouse is being pressed down.
   The position of the mouse when it is pressed down can be found using inputs.mouse.down.point.(x|y).

 - first: Returns the first element of the array.

 - num1.idiv(num2): Divides two numbers and returns an integer.

 - find_all: Finds all values that satisfy specific requirements.

 - ARRAY#intersect_rect?: Returns true or false depending on if two rectangles intersect.

 - reject: Removes elements from a collection if they meet certain requirements.

 - String interpolation: Uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

=end

MAP_FILE_PATH = 'app/map.txt' # the map.txt file in the app folder contains exported map

class MetroidvaniaStarter
  attr_accessor :grid, :inputs, :state, :outputs, :gtk

  # Calls methods needed to run the game properly.
  def tick
    defaults
    render
    calc
    process_inputs
  end

  # Sets all the default variables.
  # '||' states that initialization occurs only in the first frame.
  def defaults
    state.tile_size                = 64
    state.gravity                  = -0.2
    state.player_width             = 60
    state.player_height            = 64
    state.collision_tolerance      = 0.0
    state.previous_tile_size     ||= state.tile_size
    state.x                      ||= 0
    state.y                      ||= 800
    state.dy                     ||= 0
    state.dx                     ||= 0
    attempt_load_world_from_file
    state.world_lookup           ||= { }
    state.world_collision_rects  ||= []
    state.mode                   ||= :creating # alternates between :creating and :selecting for sprite selection
    state.select_menu            ||= [0, 720, 1280, 720]
    #=======================================IMPORTANT=======================================#
    # When adding sprites, please label them "image1.png", "image2.png", image3".png", etc.
    # Once you have done that, adjust "state.sprite_quantity" to how many sprites you have.
    #=======================================================================================#
    state.sprite_quantity        ||= 20 # IMPORTANT TO ALTER IF SPRITES ADDED IF YOU ADD MORE SPRITES
    state.sprite_coords          ||= []
    state.banner_coords          ||= [640, 680 + 720]
    state.sprite_selected        ||= 1
    state.map_saved_at           ||= 0

    # Sets all the cordinate values for the sprite selection screen into a grid
    # Displayed when 's' is pressed by player to access sprites
    if state.sprite_coords == [] # if sprite_coords is an empty array
      count = 1
      temp_x = 165 # sets a starting x and y position for display
      temp_y = 500 + 720
      state.sprite_quantity.times do # for the number of sprites you have
        state.sprite_coords += [[temp_x, temp_y, count]] # add element to sprite_coords array
        temp_x += 100 # increment temp_x
        count += 1 # increment count
        if temp_x > 1280 - (165 + 50) # if exceeding specific horizontal width on screen
          temp_x = 165 # a new row of sprites starts
          temp_y -= 75 # new row of sprites starts 75 units lower than the previous row
        end
      end
    end
  end

  # Places sprites
  def render

    # Sets the x, y, width, height, and image path for each sprite in the world collection.
    outputs.sprites << state.world.map do |x, y, sprite|
      [x * state.tile_size, # multiply by size so grid coordinates; pixel value of location
       y * state.tile_size,
       state.tile_size,
       state.tile_size,
       'sprites/image' + sprite.to_s + '.png'] # uses concatenation to create unique image path
    end

    # Outputs sprite for the player by setting x, y, width, height, and image path
    outputs.sprites << [state.x,
                        state.y,
                        state.player_width,
                        state.player_height,'sprites/player.png']

    # Outputs labels as primitives in top right of the screen
    outputs.primitives << [920, 700, 'Press \'s\' to access sprites.', 1, 0].label
    outputs.primitives << [920, 675, 'Click existing sprite to delete.', 1, 0].label

    outputs.primitives << [920, 640, '<- and -> to move.', 1, 0].label
    outputs.primitives << [920, 615, 'Press and hold space to jump.', 1, 0].label

    outputs.primitives << [920, 580, 'Press \'e\' to export current map.', 1, 0].label

    # if the map is saved and less than 120 frames have passed, the label is displayed
    if state.map_saved_at > 0 && state.map_saved_at.elapsed_time < 120
      outputs.primitives << [920, 555, 'Map has been exported!', 1, 0, 50, 100, 50].label
    end

    # If player hits 's', following appears
    if state.mode == :selecting
      # White background for sprite selection
      outputs.primitives << [state.select_menu, 255, 255, 255].solid

      # Select tile label at the top of the screen
      outputs.primitives << [state.banner_coords.x, state.banner_coords.y, "Select Sprite (sprites located in \"sprites\" folder)", 10, 1, 0, 0, 0, 255].label

      # Places sprites in locations calculated in the defaults function
      outputs.primitives << state.sprite_coords.map do |x, y, order|
        [x, y, 50, 50, 'sprites/image' + order.to_s + ".png"].sprite
      end
    end

    # Creates sprite following mouse to help indicate which sprite you have selected
    # 10 is subtracted from the mouse's x position so that the sprite is not covered by the mouse icon
    outputs.primitives << [inputs.mouse.position.x - 10, inputs.mouse.position.y,
                           10, 10, 'sprites/image' + state.sprite_selected.to_s + ".png"].sprite
  end

  # Calls methods that perform calculations
  def calc
    calc_in_game
    calc_sprite_selection
  end

  # Calls methods that perform calculations (if in creating mode)
  def calc_in_game
    return unless state.mode == :creating
    calc_world_lookup
    calc_player
  end

  def calc_world_lookup
    # If the tile size isn't equal to the previous tile size,
    # the previous tile size is set to the tile size,
    # and world_lookup hash is set to empty.
    if state.tile_size != state.previous_tile_size
      state.previous_tile_size = state.tile_size
      state.world_lookup = {}
    end

    # return if world_lookup is not empty or if world is empty
    return if state.world_lookup.keys.length > 0
    return unless state.world.length > 0

    # Searches through the world and finds the coordinates that exist
    state.world_lookup = {}
    state.world.each { |x, y| state.world_lookup[[x, y]] = true }

    # Assigns collision rects for every sprite drawn
    state.world_collision_rects =
      state.world_lookup
           .keys
           .map do |coord_x, coord_y|
             s = state.tile_size
             # Multiplying by s (the size of a tile) ensures that the rect is
             # placed exactly where you want it to be placed (causes grid to coordinate)
             # How many pixels horizontally across and vertically up and down
             x = s * coord_x
             y = s * coord_y
             {
               args:       [coord_x, coord_y],
               left_right: [x,     y + 4, s,     s - 6], # hash keys and values
               top:        [x + 4, y + 6, s - 8, s - 6],
               bottom:     [x + 1, y - 1, s - 2, s - 8],
             }
           end
  end

  # Calculates movement of player and calls methods that perform collision calculations
  def calc_player
    state.dy += state.gravity  # what goes up must come down because of gravity
    calc_box_collision
    calc_edge_collision
    state.y  += state.dy       # Since velocity is the change in position, the change in y increases by dy
    state.x  += state.dx       # Ditto line above but dx and x
    state.dx *= 0.8            # Scales dx down
  end

  # Calls methods that determine whether the player collides with any world_collision_rects.
  def calc_box_collision
    return unless state.world_lookup.keys.length > 0 # return unless hash has atleast 1 key
    collision_floor
    collision_left
    collision_right
    collision_ceiling
  end

  # Finds collisions between the bottom of the player's rect and the top of a world_collision_rect.
  def collision_floor
    return unless state.dy <= 0 # return unless player is going down or is as far down as possible
    player_rect = [state.x, next_y, state.tile_size, state.tile_size] # definition of player

    # Runs through all the sprites on the field and finds all intersections between player's
    # bottom and the top of a rect.
    floor_collisions = state.world_collision_rects
                         .find_all { |r| r[:top].intersect_rect?(player_rect, state.collision_tolerance) }
                         .first

    return unless floor_collisions # performs following changes if a collision has occurred
    state.y = floor_collisions[:top].top # y of player is set to the y of the colliding rect's top
    state.dy = 0 # no change in y because the player's path is blocked
  end

  # Finds collisions between the player's left side and the right side of a world_collision_rect.
  def collision_left
    return unless state.dx < 0 # return unless player is moving left
    player_rect = [next_x, state.y, state.tile_size, state.tile_size]

    # Runs through all the sprites on the field and finds all intersections between the player's left side
    # and the right side of a rect.
    left_side_collisions = state.world_collision_rects
                             .find_all { |r| r[:left_right].intersect_rect?(player_rect, state.collision_tolerance) }
                             .first

    return unless left_side_collisions # return unless collision occurred
    state.x = left_side_collisions[:left_right].right # sets player's x to the x of the colliding rect's right side
    state.dx = 0 # no change in x because the player's path is blocked
  end

  # Finds collisions between the right side of the player and the left side of a world_collision_rect.
  def collision_right
    return unless state.dx > 0 # return unless player is moving right
    player_rect = [next_x, state.y, state.tile_size, state.tile_size]

    # Runs through all the sprites on the field and finds all intersections between the  player's
    # right side and the left side of a rect.
    right_side_collisions = state.world_collision_rects
                              .find_all { |r| r[:left_right].intersect_rect?(player_rect, state.collision_tolerance) }
                              .first

    return unless right_side_collisions # return unless collision occurred
    state.x = right_side_collisions[:left_right].left - state.tile_size # player's x is set to the x of colliding rect's left side (minus tile size since x is the player's bottom left corner)
    state.dx = 0 # no change in x because the player's path is blocked
  end

  # Finds collisions between the top of the player's rect and the bottom of a world_collision_rect.
  def collision_ceiling
    return unless state.dy > 0 # return unless player is moving up
    player_rect = [state.x, next_y, state.player_width, state.player_height]

    # Runs through all the sprites on the field and finds all intersections between the player's top
    # and the bottom of a rect.
    ceil_collisions = state.world_collision_rects
                        .find_all { |r| r[:bottom].intersect_rect?(player_rect, state.collision_tolerance) }
                        .first

    return unless ceil_collisions # return unless collision occurred
    state.y = ceil_collisions[:bottom].y - state.tile_size # player's y is set to the y of the colliding rect's bottom (minus tile size)
    state.dy = 0 # no change in y because the player's path is blocked
  end

  # Makes sure the player remains within the screen's dimensions.
  def calc_edge_collision
    # Ensures that player doesn't fall below the map
    if next_y < 0 && state.dy < 0 # if player is moving down and is about to fall (next_y) below the map's scope
      state.y = 0 # 0 is the lowest the player can be while staying on the screen
      state.dy = 0
    # Ensures player doesn't go insanely high
    elsif next_y > 720 - state.tile_size && state.dy > 0 # if player is moving up, about to exceed map's scope
      state.y = 720 - state.tile_size # if we don't subtract tile_size, we won't be able to see the player on the screen
      state.dy = 0
    end

    # Ensures that player remains in the horizontal range its supposed to
    if state.x >= 1280 - state.tile_size && state.dx > 0 # if the player is moving too far right
      state.x = 1280 - state.tile_size # farthest right the player can be while remaining in the screen's scope
      state.dx = 0
    elsif state.x <= 0 && state.dx < 0 # if the player is moving too far left
      state.x = 0 # farthest left the player can be while remaining in the screen's scope
      state.dx = 0
    end
  end

  def calc_sprite_selection
    # Does the transition to bring down the select sprite screen
    if state.mode == :selecting && state.select_menu.y != 0
      state.select_menu.y = 0  # sets y position of select menu (shown when 's' is pressed)
      state.banner_coords.y = 680 # sets y position of Select Sprite banner
      state.sprite_coords = state.sprite_coords.map do |x, y, w, h|
        [x, y - 720, w, h] # sets definition of sprites (change '-' to '+' and the sprites can't be seen)
      end
    end

    # Does the transition to leave the select sprite screen
    if state.mode == :creating  && state.select_menu.y != 720
      state.select_menu.y = 720 # sets y position of select menu (menu is retreated back up)
      state.banner_coords.y = 1000 # sets y position of Select Sprite banner
      state.sprite_coords = state.sprite_coords.map do |x, y, w, h|
        [x, y + 720, w, h] # sets definition of all elements in collection
      end
    end
  end

  def process_inputs
    # If the state.mode is back and if the menu has retreated back up
    # call methods that process user inputs
    if state.mode == :creating
      process_inputs_player_movement
      process_inputs_place_tile
    end

    # For each sprite_coordinate added, check what sprite was selected
    if state.mode == :selecting
      state.sprite_coords.map do |x, y, order| # goes through all sprites in collection
        # checks that a specific sprite was pressed based on x, y position
        if inputs.mouse.down && # the && (and) sign means ALL statements must be true for the evaluation to be true
           inputs.mouse.down.point.x >= x      && # x is greater than or equal to sprite's x and
           inputs.mouse.down.point.x <= x + 50 && # x is less than or equal to 50 pixels to the right
           inputs.mouse.down.point.y >= y      && # y is greater than or equal to sprite's y
           inputs.mouse.down.point.y <= y + 50 # y is less than or equal to 50 pixels up
          state.sprite_selected = order # sprite is chosen
        end
      end
    end

    inputs_export_stage
    process_inputs_show_available_sprites
  end

  # Moves the player based on the keys they press on their keyboard
  def process_inputs_player_movement
    # Sets dx to 0 if the player lets go of arrow keys (player won't move left or right)
    if inputs.keyboard.key_up.right
      state.dx = 0
    elsif inputs.keyboard.key_up.left
      state.dx = 0
    end

    # Sets dx to 3 in whatever direction the player chooses when they hold down (or press) the left or right keys
    if inputs.keyboard.key_held.right
      state.dx =  3
    elsif inputs.keyboard.key_held.left
      state.dx = -3
    end

    # Sets dy to 5 to make the player ~fly~ when they press the space bar on their keyboard
    if inputs.keyboard.key_held.space
      state.dy = 5
    end
  end

  # Adds tile in the place the user holds down the mouse
  def process_inputs_place_tile
    if inputs.mouse.down # if mouse is pressed
      state.world_lookup = {}
      x, y = to_coord inputs.mouse.down.point # gets x, y coordinates for the grid

      # Checks if any coordinates duplicate (already exist in world)
      if state.world.any? { |existing_x, existing_y, n| existing_x == x && existing_y == y }
        #erases existing tile space by rejecting them from world
        state.world = state.world.reject do |existing_x, existing_y, n|
          existing_x == x && existing_y == y
        end
      else
        state.world << [x, y, state.sprite_selected] # If no duplicates, add the sprite
      end
    end
  end

  # Stores/exports world collection's info (coordinates, sprite number) into a file
  def inputs_export_stage
    if inputs.keyboard.key_down.e # if "e" is pressed
      export_string = state.world.map do |x, y, sprite_number| # stores world info in a string
        "#{x},#{y},#{sprite_number}"                           # using string interpolation
      end
      gtk.write_file(MAP_FILE_PATH, export_string.join("\n")) # writes string into a file
      state.map_saved_at = Kernel.tick_count # frame number (passage of time) when the map was saved
    end
  end

  def process_inputs_show_available_sprites
    # Based on keyboard input, the entity (:creating and :selecting) switch
    if inputs.keyboard.key_held.s && state.mode == :creating # if "s" is pressed and currently creating
      state.mode = :selecting # will change to selecting
      inputs.keyboard.clear # VERY IMPORTANT! If not present, it'll flicker between on and off
    elsif inputs.keyboard.key_held.s && state.mode == :selecting # if "s" is pressed and currently selecting
      state.mode = :creating # will change to creating
      inputs.keyboard.clear # VERY IMPORTANT! If not present, it'll flicker between on and off
    end
  end

  # Loads the world collection by reading from the map.txt file in the app folder
  def attempt_load_world_from_file
    return if state.world # return if the world collection is already populated
    state.world ||= [] # initialized as an empty collection
    exported_world = gtk.read_file(MAP_FILE_PATH) # reads the file using the path mentioned at top of code
    return unless exported_world # return unless the file read was successful
    state.world = exported_world.each_line.map do |l| # perform action on each line of exported_world
        l.split(',').map(&:to_i) # calls split using ',' as a delimiter, and invokes .map on the collection,
                                 # calling to_i (converts to integers) on each element
    end
  end

  # Adds the change in y to y to determine the next y position of the player.
  def next_y
    state.y + state.dy
  end

  # Determines next x position of player
  def next_x
    if state.dx < 0 # if the player moves left
      return state.x - (state.tile_size - state.player_width) # subtracts since the change in x is negative (player is moving left)
    else
      return state.x + (state.tile_size - state.player_width) # adds since the change in x is positive (player is moving right)
    end
  end

  def to_coord point
    # Integer divides (idiv) point.x to turn into grid
    # Then, you can just multiply each integer by state.tile_size
    # later and huzzah. Grid coordinates
    [point.x.idiv(state.tile_size), point.y.idiv(state.tile_size)]
  end
end

$metroidvania_starter = MetroidvaniaStarter.new

def tick args
    $metroidvania_starter.grid    = args.grid
    $metroidvania_starter.inputs  = args.inputs
    $metroidvania_starter.state   = args.state
    $metroidvania_starter.outputs = args.outputs
    $metroidvania_starter.gtk     = args.gtk
    $metroidvania_starter.tick
end

Box Collision 3 - main.rb link

# ./samples/04_physics_and_collisions/06_box_collision_3/app/main.rb
class Game
  attr_gtk

  def tick
    defaults
    render
    input_edit_map
    input_player
    calc_player
  end

  def defaults
    state.gravity           = -0.4
    state.drag              = 0.15
    state.tile_size         = 32
    state.player.size       = 16
    state.player.jump_power = 12

    state.tiles                 ||= []
    state.player.y              ||= 800
    state.player.x              ||= 100
    state.player.dy             ||= 0
    state.player.dx             ||= 0
    state.player.jumped_down_at ||= 0
    state.player.jumped_at      ||= 0

    calc_player_rect if !state.player.rect
  end

  def render
    outputs.labels << [10, 10.from_top, "tile: click to add a tile, hold X key and click to delete a tile."]
    outputs.labels << [10, 35.from_top, "move: use left and right to move, space to jump, down and space to jump down."]
    outputs.labels << [10, 55.from_top, "      You can jump through or jump down through tiles with a height of 1."]
    outputs.background_color = [80, 80, 80]
    outputs.sprites << tiles.map(&:sprite)
    outputs.sprites << (player.rect.merge path: 'sprites/square/green.png')

    mouse_overlay = {
      x: (inputs.mouse.x.ifloor state.tile_size),
      y: (inputs.mouse.y.ifloor state.tile_size),
      w: state.tile_size,
      h: state.tile_size,
      a: 100
    }

    mouse_overlay = mouse_overlay.merge r: 255 if state.delete_mode

    if state.mouse_held
      outputs.primitives << mouse_overlay.border!
    else
      outputs.primitives << mouse_overlay.solid!
    end
  end

  def input_edit_map
    state.mouse_held = true  if inputs.mouse.down
    state.mouse_held = false if inputs.mouse.up

    if inputs.keyboard.x
      state.delete_mode = true
    elsif inputs.keyboard.key_up.x
      state.delete_mode = false
    end

    return unless state.mouse_held

    ordinal = { x: (inputs.mouse.x.idiv state.tile_size),
                y: (inputs.mouse.y.idiv state.tile_size) }

    found = find_tile ordinal
    if !found && !state.delete_mode
      tiles << (state.new_entity :tile, ordinal)
      recompute_tiles
    elsif found && state.delete_mode
      tiles.delete found
      recompute_tiles
    end
  end

  def input_player
    player.dx += inputs.left_right

    if inputs.keyboard.key_down.space && inputs.keyboard.down
      player.dy             = player.jump_power * -1
      player.jumped_at      = 0
      player.jumped_down_at = Kernel.tick_count
    elsif inputs.keyboard.key_down.space
      player.dy             = player.jump_power
      player.jumped_at      = Kernel.tick_count
      player.jumped_down_at = 0
    end
  end

  def calc_player
    calc_player_rect
    calc_below
    calc_left
    calc_right
    calc_above
    calc_player_dy
    calc_player_dx
    reset_player if player_off_stage?
  end

  def calc_player_rect
    player.rect      = current_player_rect
    player.next_rect = player.rect.merge x: player.x + player.dx,
                                         y: player.y + player.dy
    player.prev_rect = player.rect.merge x: player.x - player.dx,
                                         y: player.y - player.dy
  end

  def calc_below
    return unless player.dy <= 0
    tiles_below = find_tiles { |t| t.rect.top <= player.prev_rect.y }
    collision = find_colliding_tile tiles_below, (player.rect.merge y: player.next_rect.y)
    return unless collision
    if collision.neighbors.b == :none && player.jumped_down_at.elapsed_time < 10
      player.dy = -1
    else
      player.y  = collision.rect.y + state.tile_size
      player.dy = 0
    end
  end

  def calc_left
    return unless player.dx < 0
    tiles_left = find_tiles { |t| t.rect.right <= player.prev_rect.left }
    collision = find_colliding_tile tiles_left, (player.rect.merge x: player.next_rect.x)
    return unless collision
    player.x  = collision.rect.right
    player.dx = 0
  end

  def calc_right
    return unless player.dx > 0
    tiles_right = find_tiles { |t| t.rect.left >= player.prev_rect.right }
    collision = find_colliding_tile tiles_right, (player.rect.merge x: player.next_rect.x)
    return unless collision
    player.x  = collision.rect.left - player.rect.w
    player.dx = 0
  end

  def calc_above
    return unless player.dy > 0
    tiles_above = find_tiles { |t| t.rect.y >= player.prev_rect.y }
    collision = find_colliding_tile tiles_above, (player.rect.merge y: player.next_rect.y)
    return unless collision
    return if collision.neighbors.t == :none
    player.dy = 0
    player.y  = collision.rect.bottom - player.rect.h
  end

  def calc_player_dx
    player.dx  = player.dx.clamp(-5,  5)
    player.dx *= 0.9
    player.x  += player.dx
  end

  def calc_player_dy
    player.y  += player.dy
    player.dy += state.gravity
    player.dy += player.dy * state.drag ** 2 * -1
  end

  def reset_player
    player.x  = 100
    player.y  = 720
    player.dy = 0
  end

  def recompute_tiles
    tiles.each do |t|
      t.w = state.tile_size
      t.h = state.tile_size
      t.neighbors = tile_neighbors t, tiles

      t.rect = [t.x * state.tile_size,
                t.y * state.tile_size,
                state.tile_size,
                state.tile_size].rect.to_hash

      sprite_sub_path = t.neighbors.mask.map { |m| flip_bit m }.join("")

      t.sprite = {
        x: t.x * state.tile_size,
        y: t.y * state.tile_size,
        w: state.tile_size,
        h: state.tile_size,
        path: "sprites/tile/wall-#{sprite_sub_path}.png"
      }
    end
  end

  def flip_bit bit
    return 0 if bit == 1
    return 1
  end

  def player
    state.player
  end

  def player_off_stage?
    player.rect.top < grid.bottom ||
    player.rect.right < grid.left ||
    player.rect.left > grid.right
  end

  def current_player_rect
    { x: player.x, y: player.y, w: player.size, h: player.size }
  end

  def tiles
    state.tiles
  end

  def find_tile ordinal
    tiles.find { |t| t.x == ordinal.x && t.y == ordinal.y }
  end

  def find_tiles &block
    tiles.find_all(&block)
  end

  def find_colliding_tile tiles, target
    tiles.find { |t| t.rect.intersect_rect? target }
  end

  def tile_neighbors tile, other_points
    t = find_tile x: tile.x + 0, y: tile.y + 1
    r = find_tile x: tile.x + 1, y: tile.y + 0
    b = find_tile x: tile.x + 0, y: tile.y - 1
    l = find_tile x: tile.x - 1, y: tile.y + 0

    tile_t, tile_r, tile_b, tile_l = 0

    tile_t = 1 if t
    tile_r = 1 if r
    tile_b = 1 if b
    tile_l = 1 if l

    state.new_entity :neighbors, mask: [tile_t, tile_r, tile_b, tile_l],
                                 t:    t ? :some : :none,
                                 b:    b ? :some : :none,
                                 l:    l ? :some : :none,
                                 r:    r ? :some : :none
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

Jump Physics - main.rb link

# ./samples/04_physics_and_collisions/07_jump_physics/app/main.rb
=begin

 Reminders:

 - args.state.new_entity: Used when we want to create a new object, like a sprite or button.
   For example, if we want to create a new button, we would declare it as a new entity and
   then define its properties. (Remember, you can use state to define ANY property and it will
   be retained across frames.)

 - args.outputs.solids: An array. The values generate a solid.
   The parameters for a solid are [X, Y, WIDTH, HEIGHT, RED, GREEN, BLUE]
   For more information about solids, go to mygame/documentation/03-solids-and-borders.md.

 - num1.greater(num2): Returns the greater value.

 - Hashes: Collection of unique keys and their corresponding values. The value can be found
   using their keys.

 - ARRAY#inside_rect?: Returns true or false depending on if the point is inside the rect.

=end

# This sample app is a game that requires the user to jump from one platform to the next.
# As the player successfully clears platforms, they become smaller and move faster.

class VerticalPlatformer
  attr_gtk

  # declares vertical platformer as new entity
  def s
    state.vertical_platformer ||= state.new_entity(:vertical_platformer)
    state.vertical_platformer
  end

  # creates a new platform using a hash
  def new_platform hash
    s.new_entity_strict(:platform, hash) # platform key
  end

  # calls methods needed for game to run properly
  def tick
    defaults
    render
    calc
    input
  end

  def init_game
    s.platforms ||= [ # initializes platforms collection with two platforms using hashes
      new_platform(x: 0, y: 0, w: 700, h: 32, dx: 1, speed: 0, rect: nil),
      new_platform(x: 0, y: 300, w: 700, h: 32, dx: 1, speed: 0, rect: nil), # 300 pixels higher
    ]

    s.tick_count  = Kernel.tick_count
    s.gravity     = -0.3 # what goes up must come down because of gravity
    s.player.platforms_cleared ||= 0 # counts how many platforms the player has successfully cleared
    s.player.x  ||= 0           # sets player values
    s.player.y  ||= 100
    s.player.w  ||= 64
    s.player.h  ||= 64
    s.player.dy ||= 0           # change in position
    s.player.dx ||= 0
    s.player_jump_power           = 15
    s.player_jump_power_duration  = 10
    s.player_max_run_speed        = 5
    s.player_speed_slowdown_rate  = 0.9
    s.player_acceleration         = 1
    s.camera ||= { y: -100 } # shows view on screen (as the player moves upward, the camera does too)
  end

  # Sets default values
  def defaults
    init_game
  end

  # Outputs objects onto the screen
  def render
    outputs.solids << s.platforms.map do |p| # outputs platforms onto screen
      [p.x + 300, p.y - s.camera[:y], p.w, p.h] # add 300 to place platform in horizontal center
      # don't forget, position of platform is denoted by bottom left hand corner
    end

    # outputs player using hash
    outputs.solids << {
      x: s.player.x + 300, # player positioned on top of platform
      y: s.player.y - s.camera[:y],
      w: s.player.w,
      h: s.player.h,
      r: 100,              # color saturation
      g: 100,
      b: 200
    }
  end

  # Performs calculations
  def calc
    s.platforms.each do |p| # for each platform in the collection
      p.rect = [p.x, p.y, p.w, p.h] # set the definition
    end

    # sets player point by adding half the player's width to the player's x
    s.player.point = [s.player.x + s.player.w.half, s.player.y] # change + to - and see what happens!

    # search the platforms collection to find if the player's point is inside the rect of a platform
    collision = s.platforms.find { |p| s.player.point.inside_rect? p.rect }

    # if collision occurred and player is moving down (or not moving vertically at all)
    if collision && s.player.dy <= 0
      s.player.y = collision.rect.y + collision.rect.h - 2 # player positioned on top of platform
      s.player.dy = 0 if s.player.dy < 0 # player stops moving vertically
      if !s.player.platform
        s.player.dx = 0 # no horizontal movement
      end
      # changes horizontal position of player by multiplying collision change in x (dx) by speed and adding it to current x
      s.player.x += collision.dx * collision.speed
      s.player.platform = collision # player is on the platform that it collided with (or landed on)
      if s.player.falling # if player is falling
        s.player.dx = 0  # no horizontal movement
      end
      s.player.falling = false
      s.player.jumped_at = nil
    else
      s.player.platform = nil # player is not on a platform
      s.player.y  += s.player.dy # velocity is the change in position
      s.player.dy += s.gravity # acceleration is the change in velocity; what goes up must come down
    end

    s.platforms.each do |p| # for each platform in the collection
      p.x += p.dx * p.speed # x is incremented by product of dx and speed (causes platform to move horizontally)
      # changes platform's x so it moves left and right across the screen (between -300 and 300 pixels)
      if p.x < -300 # if platform goes too far left
        p.dx *= -1 # dx is scaled down
        p.x = -300 # as far left as possible within scope
      elsif p.x > (1000 - p.w) # if platform's x is greater than 300
        p.dx *= -1
        p.x = (1000 - p.w) # set to 300 (as far right as possible within scope)
      end
    end

    delta = (s.player.y - s.camera[:y] - 100) # used to position camera view

    if delta > -200
      s.camera[:y] += delta * 0.01 # allows player to see view as they move upwards
      s.player.x  += s.player.dx # velocity is change in position; change in x increases by dx

      # searches platform collection to find platforms located more than 300 pixels above the player
      has_platforms = s.platforms.find { |p| p.y > (s.player.y + 300) }
      if !has_platforms # if there are no platforms 300 pixels above the player
        width = 700 - (700 * (0.1 * s.player.platforms_cleared)) # the next platform is smaller than previous
        s.player.platforms_cleared += 1 # player successfully cleared another platform
        last_platform = s.platforms[-1] # platform just cleared becomes last platform
        # another platform is created 300 pixels above the last platform, and this
        # new platform has a smaller width and moves faster than all previous platforms
        s.platforms << new_platform(x: (700 - width) * rand, # random x position
                                    y: last_platform.y + 300,
                                    w: width,
                                    h: 32,
                                    dx: 1.randomize(:sign), # random change in x
                                    speed: 2 * s.player.platforms_cleared,
                                    rect: nil)
      end
    else
      # game over
      s.as_hash.clear # otherwise clear the hash (no new platform is necessary)
      init_game
    end
  end

  # Takes input from the user to move the player
  def input
    if inputs.keyboard.space # if the space bar is pressed
      s.player.jumped_at ||= s.tick_count # set to current frame

      # if the time that has passed since the jump is less than the duration of a jump (10 frames)
      # and the player is not falling
      if s.player.jumped_at.elapsed_time < s.player_jump_power_duration && !s.player.falling
        s.player.dy = s.player_jump_power # player jumps up
      end
    end

    if inputs.keyboard.key_up.space # if space bar is in "up" state
      s.player.falling = true # player is falling
    end

    if inputs.keyboard.left # if left key is pressed
      s.player.dx -= s.player_acceleration # player's position changes, decremented by acceleration
      s.player.dx = s.player.dx.greater(-s.player_max_run_speed) # dx is either current dx or -5, whichever is greater
    elsif inputs.keyboard.right # if right key is pressed
      s.player.dx += s.player_acceleration # player's position changes, incremented by acceleration
      s.player.dx  = s.player.dx.lesser(s.player_max_run_speed) # dx is either current dx or 5, whichever is lesser
    else
      s.player.dx *= s.player_speed_slowdown_rate # scales dx down
    end
  end
end

$game = VerticalPlatformer.new

def tick args
  $game.args = args
  $game.tick
end

Bouncing On Collision - ball.rb link

# ./samples/04_physics_and_collisions/08_bouncing_on_collision/app/ball.rb
GRAVITY = -0.08

class Ball
    attr_accessor :velocity, :center, :radius, :collision_enabled

    def initialize args
        #Start the ball in the top center
        #@x = args.grid.w / 2
        #@y = args.grid.h - 20

        @velocity = {x: 0, y: 0}
        #@width =  20
        #@height = @width
        @radius = 20.0 / 2.0
        @center = {x: (args.grid.w / 2), y: (args.grid.h)}

        #@left_wall = (args.state.board_width + args.grid.w / 8)
        #@right_wall = @left_wall + args.state.board_width
        @left_wall = 0
        @right_wall = $args.grid.right

        @max_velocity = 7
        @collision_enabled = true
    end

    #Move the ball according to its velocity
    def update args
      @center.x += @velocity.x
      @center.y += @velocity.y
      @velocity.y += GRAVITY

      alpha = 0.2
      if @center.y-@radius <= 0
        @velocity.y  = (@velocity.y.abs*0.7).abs
        @velocity.x  = (@velocity.x.abs*0.9).abs * ((@velocity.x < 0) ? -1 : 1)

        if @velocity.y.abs() < alpha
          @velocity.y=0
        end
        if @velocity.x.abs() < alpha
          @velocity.x=0
        end
      end

      if @center.x > args.grid.right+@radius*2
        @center.x = 0-@radius
      elsif @center.x< 0-@radius*2
        @center.x = args.grid.right + @radius
      end
    end

    def wallBounds args
        #if @x < @left_wall || @x + @width > @right_wall
            #@velocity.x *= -1.1
            #if @velocity.x > @max_velocity
                #@velocity.x = @max_velocity
            #elsif @velocity.x < @max_velocity * -1
                #@velocity.x = @max_velocity * -1
            #end
        #end
        #if @y < 0 || @y + @height > args.grid.h
            #@velocity.y *= -1.1
            #if @velocity.y > @max_velocity
                #@velocity.y = @max_velocity
            #elsif @velocity.y < @max_velocity * -1
                #@velocity.y = @max_velocity * -1
            #end
        #end
    end

    #render the ball to the screen
    def draw args
        #args.outputs.solids << [@x, @y, @width, @height, 255, 255, 0];
        args.outputs.sprites << [
          @center.x-@radius,
          @center.y-@radius,
          @radius*2,
          @radius*2,
          "sprites/circle-white.png",
          0,
          255,
          255,    #r
          0,    #g
          255   #b
        ]
    end
  end

Bouncing On Collision - block.rb link

# ./samples/04_physics_and_collisions/08_bouncing_on_collision/app/block.rb
DEGREES_TO_RADIANS = Math::PI / 180

class Block
  def initialize(x, y, block_size, rotation)
    @x = x
    @y = y
    @block_size = block_size
    @rotation = rotation

    #The repel velocity?
    @velocity = {x: 2, y: 0}

    horizontal_offset = (3 * block_size) * Math.cos(rotation * DEGREES_TO_RADIANS)
    vertical_offset = block_size * Math.sin(rotation * DEGREES_TO_RADIANS)

    if rotation >= 0
      theta = 90 - rotation
      #The line doesn't visually line up exactly with the edge of the sprite, so artificially move it a bit
      modifier = 5
      x_offset = modifier * Math.cos(theta * DEGREES_TO_RADIANS)
      y_offset = modifier * Math.sin(theta * DEGREES_TO_RADIANS)
      @x1 = @x - x_offset
      @y1 = @y + y_offset
      @x2 = @x1 + horizontal_offset
      @y2 = @y1 + (vertical_offset * 3)

      @imaginary_line = [ @x1, @y1, @x2, @y2 ]
    else
      theta = 90 + rotation
      x_offset = @block_size * Math.cos(theta * DEGREES_TO_RADIANS)
      y_offset = @block_size * Math.sin(theta * DEGREES_TO_RADIANS)
      @x1 = @x + x_offset
      @y1 = @y + y_offset + 19
      @x2 = @x1 + horizontal_offset
      @y2 = @y1 + (vertical_offset * 3)

      @imaginary_line = [ @x1, @y1, @x2, @y2 ]
    end

  end

  def draw args
    args.outputs.sprites << [
      @x,
      @y,
      @block_size*3,
      @block_size,
      "sprites/square-green.png",
      @rotation
    ]

    args.outputs.lines << @imaginary_line
    args.outputs.solids << @debug_shape
  end

  def multiply_matricies
  end

  def calc args
    if collision? args
        collide args
    end
  end

  #Determine if the ball and block are touching
  def collision? args
    #The minimum area enclosed by the center of the ball and the 2 corners of the block
    #If the area ever drops below this value, we know there is a collision
    min_area = ((@block_size * 3) * args.state.ball.radius) / 2

    #https://www.mathopenref.com/coordtrianglearea.html
    ax = @x1
    ay = @y1
    bx = @x2
    by = @y2
    cx = args.state.ball.center.x
    cy = args.state.ball.center.y

    current_area = (ax*(by-cy)+bx*(cy-ay)+cx*(ay-by))/2

    collision = false
    if @rotation >= 0
      if (current_area < min_area &&
        current_area > 0 &&
        args.state.ball.center.y > @y1 &&
        args.state.ball.center.x < @x2)

        collision = true
      end
    else
      if (current_area < min_area &&
        current_area > 0 &&
        args.state.ball.center.y > @y2 &&
        args.state.ball.center.x > @x1)

      collision = true
      end
    end

    return collision
  end

  def collide args
    #Slope of the block
    slope = (@y2 - @y1) / (@x2 - @x1)

    #Create a unit vector and tilt it (@rotation) number of degrees
    x = -Math.cos(@rotation * DEGREES_TO_RADIANS)
    y = Math.sin(@rotation * DEGREES_TO_RADIANS)

    #Find the vector that is perpendicular to the slope
    perpVect = { x: x, y: y }
    mag  = (perpVect.x**2 + perpVect.y**2)**0.5                                 # find the magniude of the perpVect
    perpVect = {x: perpVect.x/(mag), y: perpVect.y/(mag)}                       # divide the perpVect by the magniude to make it a unit vector

    previousPosition = {                                                        # calculate an ESTIMATE of the previousPosition of the ball
      x:args.state.ball.center.x-args.state.ball.velocity.x,
      y:args.state.ball.center.y-args.state.ball.velocity.y
    }

    velocityMag = (args.state.ball.velocity.x**2 + args.state.ball.velocity.y**2)**0.5 # the current velocity magnitude of the ball
    theta_ball = Math.atan2(args.state.ball.velocity.y, args.state.ball.velocity.x)         #the angle of the ball's velocity
    theta_repel = (180 * DEGREES_TO_RADIANS) - theta_ball + (@rotation * DEGREES_TO_RADIANS)

    fbx = velocityMag * Math.cos(theta_ball)                                    #the x component of the ball's velocity
    fby = velocityMag * Math.sin(theta_ball)                                    #the y component of the ball's velocity

    frx = velocityMag * Math.cos(theta_repel)                                       #the x component of the repel's velocity | magnitude is set to twice of fbx
    fry = velocityMag * Math.sin(theta_repel)                                       #the y component of the repel's velocity | magnitude is set to twice of fby

    args.state.display_value = velocityMag
    fsumx = fbx+frx                                                             #sum of x forces
    fsumy = fby+fry                                                             #sum of y forces
    fr = velocityMag                                                            #fr is the resulting magnitude
    thetaNew = Math.atan2(fsumy, fsumx)                                         #thetaNew is the resulting angle

    xnew = fr*Math.cos(thetaNew)                                                #resulting x velocity
    ynew = fr*Math.sin(thetaNew)                                                #resulting y velocity

    dampener = 0.3
    ynew *= dampener * 0.5

    #If the bounce is very low, that means the ball is rolling and we don't want to dampenen the X velocity
    if ynew > -0.1
      xnew *= dampener
    end

    #Add the sine component of gravity back in (X component)
    gravity_x = 4 * Math.sin(@rotation * DEGREES_TO_RADIANS)
    xnew += gravity_x

    args.state.ball.velocity.x = -xnew
    args.state.ball.velocity.y = -ynew

    #Set the position of the ball to the previous position so it doesn't warp throught the block
    args.state.ball.center.x = previousPosition.x
    args.state.ball.center.y = previousPosition.y
  end
end

Bouncing On Collision - cannon.rb link

# ./samples/04_physics_and_collisions/08_bouncing_on_collision/app/cannon.rb
class Cannon
  def initialize args
    @pointA = {x: args.grid.right/2,y: args.grid.top}
    @pointB = {x: args.inputs.mouse.x, y: args.inputs.mouse.y}
  end
  def update args
    activeBall = args.state.ball
    @pointB = {x: args.inputs.mouse.x, y: args.inputs.mouse.y}

    if args.inputs.mouse.click
      alpha = 0.01
      activeBall.velocity.y = (@pointB.y - @pointA.y) * alpha
      activeBall.velocity.x = (@pointB.x - @pointA.x) * alpha
      activeBall.center = {x: (args.grid.w / 2), y: (args.grid.h)}
    end
  end
  def render args
    args.outputs.lines << [@pointA.x, @pointA.y, @pointB.x, @pointB.y]
  end
end

Bouncing On Collision - main.rb link

# ./samples/04_physics_and_collisions/08_bouncing_on_collision/app/main.rb
INFINITY= 10**10

require 'app/vector2d.rb'
require 'app/peg.rb'
require 'app/block.rb'
require 'app/ball.rb'
require 'app/cannon.rb'


#Method to init default values
def defaults args
  args.state.pegs ||= []
  args.state.blocks ||= []
  args.state.cannon ||= Cannon.new args
  args.state.ball ||= Ball.new args
  args.state.horizontal_offset ||= 0
  init_pegs args
  init_blocks args

  args.state.display_value ||= "test"
end

begin :default_methods
  def init_pegs args
    num_horizontal_pegs = 14
    num_rows = 5

    return unless args.state.pegs.count < num_rows * num_horizontal_pegs

    block_size = 32
    block_spacing = 50
    total_width = num_horizontal_pegs * (block_size + block_spacing)
    starting_offset = (args.grid.w - total_width) / 2 + block_size

    for i in (0...num_rows)
      for j in (0...num_horizontal_pegs)
        row_offset = 0
        if i % 2 == 0
          row_offset = 20
        else
          row_offset = -20
        end
        args.state.pegs.append(Peg.new(j * (block_size+block_spacing) + starting_offset + row_offset, (args.grid.h - block_size * 2) - (i * block_size * 2)-90, block_size))
      end
    end

  end

  def init_blocks args
    return unless args.state.blocks.count < 10

    #Sprites are rotated in degrees, but the Ruby math functions work on radians
    radians_to_degrees = Math::PI / 180

    block_size = 25
    #Rotation angle (in degrees) of the blocks
    rotation = 30
    vertical_offset = block_size * Math.sin(rotation * radians_to_degrees)
    horizontal_offset = (3 * block_size) * Math.cos(rotation * radians_to_degrees)
    center = args.grid.w / 2

    for i in (0...5)
      #Create a ramp of blocks. Not going to be perfect because of the float to integer conversion and anisotropic to isotropic coversion
      args.state.blocks.append(Block.new((center + 100 + (i * horizontal_offset)).to_i, 100 + (vertical_offset * i) + (i * block_size), block_size, rotation))
      args.state.blocks.append(Block.new((center - 100 - (i * horizontal_offset)).to_i, 100 + (vertical_offset * i) + (i * block_size), block_size, -rotation))
    end
  end
end

#Render loop
def render args
  args.outputs.borders << args.state.game_area
  render_pegs args
  render_blocks args
  args.state.cannon.render args
  args.state.ball.draw args
end

begin :render_methods
  #Draw the pegs in a grid pattern
  def render_pegs args
    args.state.pegs.each do |peg|
      peg.draw args
    end
  end

  def render_blocks args
    args.state.blocks.each do |block|
      block.draw args
    end
  end

end

#Calls all methods necessary for performing calculations
def calc args
  args.state.pegs.each do |peg|
    peg.calc args
  end

  args.state.blocks.each do |block|
    block.calc args
  end

  args.state.ball.update args
  args.state.cannon.update args
end

begin :calc_methods

end

def tick args
  defaults args
  render args
  calc args
end

Bouncing On Collision - peg.rb link

# ./samples/04_physics_and_collisions/08_bouncing_on_collision/app/peg.rb
class Peg
  def initialize(x, y, block_size)
    @x = x                    # x cordinate of the LEFT side of the peg
    @y = y                    # y cordinate of the RIGHT side of the peg
    @block_size = block_size  # diameter of the peg

    @radius = @block_size/2.0 # radius of the peg
    @center = {               # cordinatees of the CENTER of the peg
      x: @x+@block_size/2.0,
      y: @y+@block_size/2.0
    }

    @r = 255 # color of the peg
    @g = 0
    @b = 0

    @velocity = {x: 2, y: 0}
  end

  def draw args
    args.outputs.sprites << [ # draw the peg according to the @x, @y, @radius, and the RGB
      @x,
      @y,
      @radius*2.0,
      @radius*2.0,
      "sprites/circle-white.png",
      0,
      255,
      @r,    #r
      @g,    #g
      @b   #b
    ]
  end


  def calc args
    if collisionWithBounce? args # if the is a collision with the bouncing ball
      collide args
      @r = 0
      @b = 0
      @g = 255
    else
    end
  end


  # do two circles (the ball and this peg) intersect
  def collisionWithBounce? args
    squareDistance = (  # the squared distance between the ball's center and this peg's center
      (args.state.ball.center.x - @center.x) ** 2.0 +
      (args.state.ball.center.y - @center.y) ** 2.0
    )
    radiusSum = (  # the sum of the radius squared of the this peg and the ball
      (args.state.ball.radius + @radius) ** 2.0
    )
    # if the squareDistance is less or equal to radiusSum, then there is a radial intersection between the ball and this peg
    return (squareDistance <= radiusSum)
  end

  # ! The following links explain the getRepelMagnitude function !
  # https://raw.githubusercontent.com/DragonRuby/dragonruby-game-toolkit-physics/master/docs/docImages/LinearCollider_4.png
  # https://raw.githubusercontent.com/DragonRuby/dragonruby-game-toolkit-physics/master/docs/docImages/LinearCollider_5.png
  # https://github.com/DragonRuby/dragonruby-game-toolkit-physics/blob/master/docs/LinearCollider.md
  def getRepelMagnitude (args, fbx, fby, vrx, vry, ballMag)
    a = fbx ; b = vrx ; c = fby
    d = vry ; e = ballMag
    if b**2 + d**2 == 0
      #unexpected
    end

    x1 = (-a*b+-c*d + (e**2 * b**2 - b**2 * c**2 + 2*a*b*c*d + e**2 + d**2 - a**2 * d**2)**0.5)/(b**2 + d**2)
    x2 = -((a*b + c*d + (e**2 * b**2 - b**2 * c**2 + 2*a*b*c*d + e**2 * d**2 - a**2 * d**2)**0.5)/(b**2 + d**2))

    err = 0.00001
    o = ((fbx + x1*vrx)**2 + (fby + x1*vry)**2 ) ** 0.5
    p = ((fbx + x2*vrx)**2 + (fby + x2*vry)**2 ) ** 0.5
    r = 0

    if (ballMag >= o-err and ballMag <= o+err)
      r = x1
    elsif (ballMag >= p-err and ballMag <= p+err)
      r = x2
    else
      #unexpected
    end

    if (args.state.ball.center.x > @center.x)
      return x2*-1
    end

    return x2

    #return r
  end

  #this sets the new velocity of the ball once it has collided with this peg
  def collide args
    normalOfRCCollision = [                                                     #this is the normal of the collision in COMPONENT FORM
      {x: @center.x, y: @center.y},                                             #see https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.mathscard.co.uk%2Fonline%2Fcircle-coordinate-geometry%2F&psig=AOvVaw2GcD-e2-nJR_IUKpw3hO98&ust=1605731315521000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCMjBo7e1iu0CFQAAAAAdAAAAABAD
      {x: args.state.ball.center.x, y: args.state.ball.center.y},
    ]

    normalSlope = (                                                             #normalSlope is the slope of normalOfRCCollision
      (normalOfRCCollision[1].y - normalOfRCCollision[0].y) /
      (normalOfRCCollision[1].x - normalOfRCCollision[0].x)
    )
    slope = normalSlope**-1.0 * -1                                              # slope is the slope of the tangent
    # args.state.display_value = slope
    pointA = {                                                                  # pointA and pointB are using the var slope to tangent in COMPONENT FORM
      x: args.state.ball.center.x-1,
      y: -(slope-args.state.ball.center.y)
    }
    pointB = {
      x: args.state.ball.center.x+1,
      y: slope+args.state.ball.center.y
    }

    perpVect = {x: pointB.x - pointA.x, y:pointB.y - pointA.y}                  # perpVect is to be VECTOR of the perpendicular tangent
    mag  = (perpVect.x**2 + perpVect.y**2)**0.5                                 # find the magniude of the perpVect
    perpVect = {x: perpVect.x/(mag), y: perpVect.y/(mag)}                       # divide the perpVect by the magniude to make it a unit vector
    perpVect = {x: -perpVect.y, y: perpVect.x}                                  # swap the x and y and multiply by -1 to make the vector perpendicular
    args.state.display_value = perpVect
    if perpVect.y > 0                                                           #ensure perpVect points upward
      perpVect = {x: perpVect.x*-1, y: perpVect.y*-1}
    end

    previousPosition = {                                                        # calculate an ESTIMATE of the previousPosition of the ball
      x:args.state.ball.center.x-args.state.ball.velocity.x,
      y:args.state.ball.center.y-args.state.ball.velocity.y
    }

    yInterc = pointA.y + -slope*pointA.x
    if slope == INFINITY                                                        # the perpVect presently either points in the correct dirrection or it is 180 degrees off we need to correct this
      if previousPosition.x < pointA.x
        perpVect = {x: perpVect.x*-1, y: perpVect.y*-1}
        yInterc = -INFINITY
      end
    elsif previousPosition.y < slope*previousPosition.x + yInterc               # check if ball is bellow or above the collider to determine if perpVect is - or +
      perpVect = {x: perpVect.x*-1, y: perpVect.y*-1}
    end

    velocityMag =                                                               # the current velocity magnitude of the ball
      (args.state.ball.velocity.x**2 + args.state.ball.velocity.y**2)**0.5
    theta_ball=
      Math.atan2(args.state.ball.velocity.y,args.state.ball.velocity.x)         #the angle of the ball's velocity
    theta_repel=
      Math.atan2(args.state.ball.center.y,args.state.ball.center.x)             #the angle of the repelling force(perpVect)

    fbx = velocityMag * Math.cos(theta_ball)                                    #the x component of the ball's velocity
    fby = velocityMag * Math.sin(theta_ball)                                    #the y component of the ball's velocity
    repelMag = getRepelMagnitude(                                               # the magniude of the collision vector
      args,
      fbx,
      fby,
      perpVect.x,
      perpVect.y,
      (args.state.ball.velocity.x**2 + args.state.ball.velocity.y**2)**0.5
    )
    frx = repelMag* Math.cos(theta_repel)                                       #the x component of the repel's velocity | magnitude is set to twice of fbx
    fry = repelMag* Math.sin(theta_repel)                                       #the y component of the repel's velocity | magnitude is set to twice of fby

    fsumx = fbx+frx                            # sum of x forces
    fsumy = fby+fry                            # sum of y forces
    fr = velocityMag                           # fr is the resulting magnitude
    thetaNew = Math.atan2(fsumy, fsumx)        # thetaNew is the resulting angle
    xnew = fr*Math.cos(thetaNew)               # resulting x velocity
    ynew = fr*Math.sin(thetaNew)               # resulting y velocity
    if (args.state.ball.center.x >= @center.x) # this is necessary for the ball colliding on the right side of the peg
      xnew=xnew.abs
    end

    args.state.ball.velocity.x = xnew                                           # set the x-velocity to the new velocity
    if args.state.ball.center.y > @center.y                                     # if the ball is above the middle of the peg we need to temporarily ignore some of the gravity
      args.state.ball.velocity.y = ynew + GRAVITY * 0.01
    else
      args.state.ball.velocity.y = ynew - GRAVITY * 0.01                        # if the ball is bellow the middle of the peg we need to temporarily increase the power of the gravity
    end

    args.state.ball.center.x+= args.state.ball.velocity.x                       # update the position of the ball so it never looks like the ball is intersecting the circle
    args.state.ball.center.y+= args.state.ball.velocity.y
  end
end

Bouncing On Collision - vector2d.rb link

# ./samples/04_physics_and_collisions/08_bouncing_on_collision/app/vector2d.rb
class Vector2d
    attr_accessor :x, :y

    def initialize x=0, y=0
      @x=x
      @y=y
    end

    #returns a vector multiplied by scalar x
    #x [float] scalar
    def mult x
      r = Vector2d.new(0,0)
      r.x=@x*x
      r.y=@y*x
      r
    end

    # vect [Vector2d] vector to copy
    def copy vect
      Vector2d.new(@x, @y)
    end

    #returns a new vector equivalent to this+vect
    #vect [Vector2d] vector to add to self
    def add vect
      Vector2d.new(@x+vect.x,@y+vect.y)
    end

    #returns a new vector equivalent to this-vect
    #vect [Vector2d] vector to subtract to self
    def sub vect
      Vector2d.new(@x-vect.c, @y-vect.y)
    end

    #return the magnitude of the vector
    def mag
      ((@x**2)+(@y**2))**0.5
    end

    #returns a new normalize version of the vector
    def normalize
      Vector2d.new(@x/mag, @y/mag)
    end

    #TODO delet?
    def distABS vect
      (((vect.x-@x)**2+(vect.y-@y)**2)**0.5).abs()
    end
  end

Arbitrary Collision - ball.rb link

# ./samples/04_physics_and_collisions/09_arbitrary_collision/app/ball.rb

class Ball
    attr_accessor :velocity, :child, :parent, :number, :leastChain
    attr_reader :x, :y, :hypotenuse, :width, :height

    def initialize args, number, leastChain, parent, child
        #Start the ball in the top center
        @number = number
        @leastChain = leastChain
        @x = args.grid.w / 2
        @y = args.grid.h - 20

        @velocity = Vector2d.new(2, -2)
        @width =  10
        @height = 10

        @left_wall = (args.state.board_width + args.grid.w / 8)
        @right_wall = @left_wall + args.state.board_width

        @max_velocity = MAX_VELOCITY

        @child = child
        @parent = parent

        @past = [{x: @x, y: @y}]
        @next = nil
    end

    def reassignLeastChain (lc=nil)
      if (lc == nil)
        lc = @number
      end
      @leastChain = lc
      if (parent != nil)
        @parent.reassignLeastChain(lc)
      end

    end

    def makeLeader args
      if isLeader
        return
      end
      @parent.reassignLeastChain
      args.state.ballParents.push(self)
      @parent = nil

    end

    def isLeader
      return (parent == nil)
    end

    def receiveNext (p)
      #trace!
      if parent != nil
        @x = p[:x]
        @y = p[:y]
        @velocity = p[:velocity]
        #puts @x.to_s + "|" + @y.to_s + "|"[email protected]_s
        @past.append(p)
        if (@past.length >= BALL_DISTANCE)
          if (@child != nil)
            @child.receiveNext(@past[0])
            @past.shift
          end
        end
      end
    end

    #Move the ball according to its velocity
    def update args

        if isLeader
          wallBounds args
          @x += @velocity.x
          @y += @velocity.y
          @past.append({x: @x, y: @y, velocity: @velocity})
          #puts @past

          if (@past.length >= BALL_DISTANCE)
            if (@child != nil)
              @child.receiveNext(@past[0])
              @past.shift
            end
          end

        else
          puts "unexpected"
          raise "unexpected"
        end
    end

    def wallBounds args
        b= false
        if @x < @left_wall
          @velocity.x = @velocity.x.abs() * 1
          b=true
        elsif @x + @width > @right_wall
          @velocity.x = @velocity.x.abs() * -1
          b=true
        end
        if @y < 0
          @velocity.y = @velocity.y.abs() * 1
          b=true
        elsif @y + @height > args.grid.h
          @velocity.y = @velocity.y.abs() * -1
          b=true
        end
        mag = (@velocity.x**2.0 + @velocity.y**2.0)**0.5
        if (b == true && mag < MAX_VELOCITY)
          @velocity.x*=1.1;
          @velocity.y*=1.1;
        end

    end

    #render the ball to the screen
    def draw args

        #update args
        #args.outputs.solids << [@x, @y, @width, @height, 255, 255, 0];
        #args.outputs.sprits << {
          #x: @x,
          #y: @y,
          #w: @width,
          #h: @height,
          #path: "sprites/ball10.png"
        #}
        #args.outputs.sprites <<[@x, @y, @width, @height, "sprites/ball10.png"]
        args.outputs.sprites << {x: @x, y: @y, w: @width, h: @height, path:"sprites/ball10.png" }
    end

    def getDraw args
      #wallBounds args
      #update args
      #args.outputs.labels << [@x, @y, @number.to_s + "|" + @leastChain.to_s]
      return [@x, @y, @width, @height, "sprites/ball10.png"]
    end

    def getPoints args
      points = [
        {x:@x+@width/2, y: @y},
        {x:@x+@width, y:@y+@height/2},
        {x:@x+@width/2,y:@y+@height},
        {x:@x,y:@y+@height/2}
      ]
      #psize = 5.0
      #for p in points
        #args.outputs.solids << [p.x-psize/2.0, p.y-psize/2.0, psize, psize, 0, 0, 0];
      #end
      return points
    end

    def serialize
      {x: @x, y:@y}
    end

    def inspect
      serialize.to_s
    end

    def to_s
      serialize.to_s
    end
  end

Arbitrary Collision - blocks.rb link

# ./samples/04_physics_and_collisions/09_arbitrary_collision/app/blocks.rb
MAX_COUNT=100

def universalUpdateOne args, shape
  didHit = false
  hitters = []
  #puts shape.to_s
  toCollide = nil
  for b in args.state.balls
    if [b.x, b.y, b.width, b.height].intersect_rect?(shape.bold)
      didSquare = false
      for s in shape.squareColliders
        if (s.collision?(args, b))
          didSquare = true
          didHit = true
          #s.collide(args, b)
          toCollide = s
          #hitter = b
          hitters.append(b)
        end #end if
      end #end for
      if (didSquare == false)
        for c in shape.colliders
          #puts args.state.ball.velocity
          if c.collision?(args, b.getPoints(args),b)
            #c.collide args, b
            toCollide = c
            didHit = true
            hitters.append(b)
          end #end if
        end #end for
      end #end if
    end#end if
  end#end for
  if (didHit)
    shape.count=0
    hitters = hitters.uniq
    for hitter in hitters
      hitter.makeLeader args
      #toCollide.collide(args, hitter)
      if shape.home == "squares"
        args.state.squares.delete(shape)
      elsif shape.home == "tshapes"
        args.state.tshapes.delete(shape)
      else shape.home == "lines"
        args.state.lines.delete(shape)
      end
    end

    #puts "HIT!" + hitter.number
  end
end

def universalUpdate args, shape
  #puts shape.home
  if (shape.count <= 1)
    universalUpdateOne args, shape
    return
  end

  didHit = false
  hitter = nil
  for b in args.state.ballParents
    if [b.x, b.y, b.width, b.height].intersect_rect?(shape.bold)
      didSquare = false
      for s in shape.squareColliders
        if (s.collision?(args, b))
          didSquare = true
          didHit = true
          s.collide(args, b)
          hitter = b
        end
      end
      if (didSquare == false)
        for c in shape.colliders
          #puts args.state.ball.velocity
          if c.collision?(args, b.getPoints(args),b)
            c.collide args, b
            didHit = true
            hitter = b
          end
        end
      end
    end
  end
  if (didHit)
    shape.count=shape.count-1
    shape.damageCount.append([(hitter.leastChain+1 - hitter.number)-1, Kernel.tick_count])

  end
  i=0
  while i < shape.damageCount.length
    if shape.damageCount[i][0] <= 0
      shape.damageCount.delete_at(i)
      i-=1
    elsif shape.damageCount[i][1].elapsed_time > BALL_DISTANCE and shape.damageCount[i][0] > 1
      shape.count-=1
      shape.damageCount[i][0]-=1
      shape.damageCount[i][1] = Kernel.tick_count
    end
    i+=1
  end
end


class Square
   attr_accessor :count, :x, :y, :home, :bold, :squareColliders, :colliders, :damageCount
   def initialize(args, x, y, block_size, orientation, block_offset)
        @x = x * block_size
        @y = y * block_size
        @block_size = block_size
        @block_offset = block_offset
        @orientation = orientation
        @damageCount = []
        @home = 'squares'


        Kernel.srand()
        @r = rand(255)
        @g = rand(255)
        @b = rand(255)

        @count = rand(MAX_COUNT)+1

        x_offset = (args.state.board_width + args.grid.w / 8) + @block_offset / 2
        @x_adjusted = @x + x_offset
        @y_adjusted = @y
        @size_adjusted = @block_size * 2 - @block_offset

        hypotenuse=args.state.ball_hypotenuse
        @bold = [(@x_adjusted-hypotenuse/2)-1, (@y_adjusted-hypotenuse/2)-1, @size_adjusted + hypotenuse + 2, @size_adjusted + hypotenuse + 2]

        @points = [
          {x:@x_adjusted, y:@y_adjusted},
          {x:@x_adjusted+@size_adjusted, y:@y_adjusted},
          {x:@x_adjusted+@size_adjusted, y:@y_adjusted+@size_adjusted},
          {x:@x_adjusted, y:@y_adjusted+@size_adjusted}
        ]
        @squareColliders = [
          SquareCollider.new(@points[0].x,@points[0].y,{x:-1,y:-1}),
          SquareCollider.new(@points[1].x-COLLISIONWIDTH,@points[1].y,{x:1,y:-1}),
          SquareCollider.new(@points[2].x-COLLISIONWIDTH,@points[2].y-COLLISIONWIDTH,{x:1,y:1}),
          SquareCollider.new(@points[3].x,@points[3].y-COLLISIONWIDTH,{x:-1,y:1}),
        ]
        @colliders = [
          LinearCollider.new(@points[0],@points[1], :neg),
          LinearCollider.new(@points[1],@points[2], :neg),
          LinearCollider.new(@points[2],@points[3], :pos),
          LinearCollider.new(@points[0],@points[3], :pos)
        ]
   end

   def draw(args)
    #Offset the coordinates to the edge of the game area
    x_offset = (args.state.board_width + args.grid.w / 8) + @block_offset / 2
    #args.outputs.solids << [@x + x_offset, @y, @block_size * 2 - @block_offset, @block_size * 2 - @block_offset, @r, @g, @b]
    args.outputs.solids <<{x: (@x + x_offset), y: (@y), w: (@block_size * 2 - @block_offset), h: (@block_size * 2 - @block_offset), r: @r , g: @g , b: @b }
    #args.outputs.solids << @bold.append([255,0,0])
    args.outputs.labels << [@x + x_offset + (@block_size * 2 - @block_offset)/2, (@y) + (@block_size * 2 - @block_offset)/2, @count.to_s]

   end

   def update args
     universalUpdate args, self
   end
end

class TShape
    attr_accessor :count, :x, :y, :home, :bold, :squareColliders, :colliders, :damageCount
    def initialize(args, x, y, block_size, orientation, block_offset)
        @x = x * block_size
        @y = y * block_size
        @block_size = block_size
        @block_offset = block_offset
        @orientation = orientation
        @damageCount = []
        @home = "tshapes"

        Kernel.srand()
        @r = rand(255)
        @g = rand(255)
        @b = rand(255)

        @count = rand(MAX_COUNT)+1


        @shapePoints = getShapePoints(args)
        minX={x:INFINITY, y:0}
        minY={x:0, y:INFINITY}
        maxX={x:-INFINITY, y:0}
        maxY={x:0, y:-INFINITY}
        for p in @shapePoints
          if p.x < minX.x
            minX = p
          end
          if p.x > maxX.x
            maxX = p
          end
          if p.y < minY.y
            minY = p
          end
          if p.y > maxY.y
            maxY = p
          end
        end


        hypotenuse=args.state.ball_hypotenuse

        @bold = [(minX.x-hypotenuse/2)-1, (minY.y-hypotenuse/2)-1, -((minX.x-hypotenuse/2)-1)+(maxX.x + hypotenuse + 2), -((minY.y-hypotenuse/2)-1)+(maxY.y + hypotenuse + 2)]
    end
    def getShapePoints(args)
      points=[]
      x_offset = (args.state.board_width + args.grid.w / 8) + (@block_offset / 2)

      if @orientation == :right
          #args.outputs.solids << [@x + x_offset, @y, @block_size - @block_offset, @block_size * 3 - @block_offset, @r, @g, @b]
          #args.outputs.solids << [@x + x_offset, @y + @block_size, @block_size * 2, @block_size, @r, @g, @b]
          points = [
            {x:@x + x_offset, y:@y},
            {x:(@x + x_offset)+(@block_size - @block_offset), y:@y},
            {x:(@x + x_offset)+(@block_size - @block_offset),y:@y + @block_size},
            {x:(@x + x_offset)+ @block_size * 2,y:@y + @block_size},
            {x:(@x + x_offset)+ @block_size * 2,y:@y + @block_size+@block_size},
            {x:(@x + x_offset)+(@block_size - @block_offset),y:@y + @block_size+@block_size},
            {x:(@x + x_offset)+(@block_size - @block_offset), y:@y+ @block_size * 3 - @block_offset},
            {x:@x + x_offset , y:@y+ @block_size * 3 - @block_offset}
          ]
          @squareColliders = [
            SquareCollider.new(points[0].x,points[0].y,{x:-1,y:-1}),
            SquareCollider.new(points[1].x-COLLISIONWIDTH,points[1].y,{x:1,y:-1}),
            SquareCollider.new(points[2].x,points[2].y-COLLISIONWIDTH,{x:1,y:-1}),
            SquareCollider.new(points[3].x-COLLISIONWIDTH,points[3].y,{x:1,y:-1}),
            SquareCollider.new(points[4].x-COLLISIONWIDTH,points[4].y-COLLISIONWIDTH,{x:1,y:1}),
            SquareCollider.new(points[5].x,points[5].y,{x:1,y:1}),
            SquareCollider.new(points[6].x-COLLISIONWIDTH,points[6].y-COLLISIONWIDTH,{x:1,y:1}),
            SquareCollider.new(points[7].x,points[7].y-COLLISIONWIDTH,{x:-1,y:1}),
          ]
          @colliders = [
            LinearCollider.new(points[0],points[1], :neg),
            LinearCollider.new(points[1],points[2], :neg),
            LinearCollider.new(points[2],points[3], :neg),
            LinearCollider.new(points[3],points[4], :neg),
            LinearCollider.new(points[4],points[5], :pos),
            LinearCollider.new(points[5],points[6], :neg),
            LinearCollider.new(points[6],points[7], :pos),
            LinearCollider.new(points[0],points[7], :pos)
          ]
      elsif @orientation == :up
          #args.outputs.solids << [@x + x_offset, @y, @block_size * 3 - @block_offset, @block_size - @block_offset, @r, @g, @b]
          #args.outputs.solids << [@x + x_offset + @block_size, @y, @block_size, @block_size * 2, @r, @g, @b]
          points = [
            {x:@x + x_offset, y:@y},
            {x:(@x + x_offset)+(@block_size * 3 - @block_offset), y:@y},
            {x:(@x + x_offset)+(@block_size * 3 - @block_offset), y:@y+(@block_size - @block_offset)},
            {x:@x + x_offset + @block_size + @block_size, y:@y+(@block_size - @block_offset)},
            {x:@x + x_offset + @block_size + @block_size, y:@y+@block_size*2},
            {x:@x + x_offset + @block_size, y:@y+@block_size*2},
            {x:@x + x_offset + @block_size, y:@y+(@block_size - @block_offset)},
            {x:@x + x_offset, y:@y+(@block_size - @block_offset)}
          ]
          @squareColliders = [
            SquareCollider.new(points[0].x,points[0].y,{x:-1,y:-1}),
            SquareCollider.new(points[1].x-COLLISIONWIDTH,points[1].y,{x:1,y:-1}),
            SquareCollider.new(points[2].x-COLLISIONWIDTH,points[2].y-COLLISIONWIDTH,{x:1,y:1}),
            SquareCollider.new(points[3].x,points[3].y,{x:1,y:1}),
            SquareCollider.new(points[4].x-COLLISIONWIDTH,points[4].y-COLLISIONWIDTH,{x:1,y:1}),
            SquareCollider.new(points[5].x,points[5].y-COLLISIONWIDTH,{x:-1,y:1}),
            SquareCollider.new(points[6].x-COLLISIONWIDTH,points[6].y,{x:-1,y:1}),
            SquareCollider.new(points[7].x,points[7].y-COLLISIONWIDTH,{x:-1,y:1}),
          ]
          @colliders = [
            LinearCollider.new(points[0],points[1], :neg),
            LinearCollider.new(points[1],points[2], :neg),
            LinearCollider.new(points[2],points[3], :pos),
            LinearCollider.new(points[3],points[4], :neg),
            LinearCollider.new(points[4],points[5], :pos),
            LinearCollider.new(points[5],points[6], :neg),
            LinearCollider.new(points[6],points[7], :pos),
            LinearCollider.new(points[0],points[7], :pos)
          ]
      elsif @orientation == :left
          #args.outputs.solids << [@x + x_offset + @block_size, @y, @block_size - @block_offset, @block_size * 3 - @block_offset, @r, @g, @b]
          #args.outputs.solids << [@x + x_offset, @y + @block_size, @block_size * 2 - @block_offset, @block_size - @block_offset, @r, @g, @b]
          xh = @x + x_offset
          #points = [
            #{x:@x + x_offset, y:@y},
            #{x:(@x + x_offset)+(@block_size - @block_offset), y:@y},
            #{x:(@x + x_offset)+(@block_size - @block_offset),y:@y + @block_size},
            #{x:(@x + x_offset)+ @block_size * 2,y:@y + @block_size},
            #{x:(@x + x_offset)+ @block_size * 2,y:@y + @block_size+@block_size},
            #{x:(@x + x_offset)+(@block_size - @block_offset),y:@y + @block_size+@block_size},
            #{x:(@x + x_offset)+(@block_size - @block_offset), y:@y+ @block_size * 3 - @block_offset},
            #{x:@x + x_offset , y:@y+ @block_size * 3 - @block_offset}
          #]
          points = [
            {x:@x + x_offset + @block_size, y:@y},
            {x:@x + x_offset + @block_size + (@block_size - @block_offset), y:@y},
            {x:@x + x_offset + @block_size + (@block_size - @block_offset),y:@y+@block_size*3- @block_offset},
            {x:@x + x_offset + @block_size, y:@y+@block_size*3- @block_offset},
            {x:@x + x_offset+@block_size, y:@y+@block_size*2- @block_offset},
            {x:@x + x_offset, y:@y+@block_size*2- @block_offset},
            {x:@x + x_offset, y:@y+@block_size},
            {x:@x + x_offset+@block_size, y:@y+@block_size}
          ]
          @squareColliders = [
            SquareCollider.new(points[0].x,points[0].y,{x:-1,y:-1}),
            SquareCollider.new(points[1].x-COLLISIONWIDTH,points[1].y,{x:1,y:-1}),
            SquareCollider.new(points[2].x-COLLISIONWIDTH,points[2].y-COLLISIONWIDTH,{x:1,y:1}),
            SquareCollider.new(points[3].x,points[3].y-COLLISIONWIDTH,{x:-1,y:1}),
            SquareCollider.new(points[4].x-COLLISIONWIDTH,points[4].y,{x:-1,y:1}),
            SquareCollider.new(points[5].x,points[5].y-COLLISIONWIDTH,{x:-1,y:1}),
            SquareCollider.new(points[6].x,points[6].y,{x:-1,y:-1}),
            SquareCollider.new(points[7].x-COLLISIONWIDTH,points[7].y-COLLISIONWIDTH,{x:-1,y:-1}),
          ]
          @colliders = [
            LinearCollider.new(points[0],points[1], :neg),
            LinearCollider.new(points[1],points[2], :neg),
            LinearCollider.new(points[2],points[3], :pos),
            LinearCollider.new(points[3],points[4], :neg),
            LinearCollider.new(points[4],points[5], :pos),
            LinearCollider.new(points[5],points[6], :neg),
            LinearCollider.new(points[6],points[7], :neg),
            LinearCollider.new(points[0],points[7], :pos)
          ]
      elsif @orientation == :down
          #args.outputs.solids << [@x + x_offset, @y + @block_size, @block_size * 3 - @block_offset, @block_size - @block_offset, @r, @g, @b]
          #args.outputs.solids << [@x + x_offset + @block_size, @y, @block_size - @block_offset, @block_size * 2 - @block_offset, @r, @g, @b]

          points = [
            {x:@x + x_offset, y:@y+(@block_size*2)-@block_offset},
            {x:@x + x_offset+ @block_size*3-@block_offset, y:@y+(@block_size*2)-@block_offset},
            {x:@x + x_offset+ @block_size*3-@block_offset, y:@y+(@block_size)},
            {x:@x + x_offset+ @block_size*2-@block_offset, y:@y+(@block_size)},
            {x:@x + x_offset+ @block_size*2-@block_offset, y:@y},#
            {x:@x + x_offset+ @block_size, y:@y},#
            {x:@x + x_offset + @block_size, y:@y+(@block_size)},
            {x:@x + x_offset, y:@y+(@block_size)}
          ]
          @squareColliders = [
            SquareCollider.new(points[0].x,points[0].y-COLLISIONWIDTH,{x:-1,y:1}),
            SquareCollider.new(points[1].x-COLLISIONWIDTH,points[1].y-COLLISIONWIDTH,{x:1,y:1}),
            SquareCollider.new(points[2].x-COLLISIONWIDTH,points[2].y,{x:1,y:-1}),
            SquareCollider.new(points[3].x,points[3].y-COLLISIONWIDTH,{x:1,y:-1}),
            SquareCollider.new(points[4].x-COLLISIONWIDTH,points[4].y,{x:1,y:-1}),
            SquareCollider.new(points[5].x,points[5].y,{x:-1,y:-1}),
            SquareCollider.new(points[6].x-COLLISIONWIDTH,points[6].y-COLLISIONWIDTH,{x:-1,y:-1}),
            SquareCollider.new(points[7].x,points[7].y,{x:-1,y:-1}),
          ]
          @colliders = [
            LinearCollider.new(points[0],points[1], :pos),
            LinearCollider.new(points[1],points[2], :pos),
            LinearCollider.new(points[2],points[3], :neg),
            LinearCollider.new(points[3],points[4], :pos),
            LinearCollider.new(points[4],points[5], :neg),
            LinearCollider.new(points[5],points[6], :pos),
            LinearCollider.new(points[6],points[7], :neg),
            LinearCollider.new(points[0],points[7], :neg)
          ]
      end
      return points
    end

    def draw(args)
        #Offset the coordinates to the edge of the game area
        x_offset = (args.state.board_width + args.grid.w / 8) + (@block_offset / 2)

        if @orientation == :right
            #args.outputs.solids << [@x + x_offset, @y, @block_size - @block_offset, @block_size * 3 - @block_offset, @r, @g, @b]
            args.outputs.solids << {x: (@x + x_offset), y: @y, w: @block_size - @block_offset, h: (@block_size * 3 - @block_offset), r: @r , g: @g, b: @b}
            #args.outputs.solids << [@x + x_offset, @y + @block_size, @block_size * 2, @block_size, @r, @g, @b]
            args.outputs.solids << {x: (@x + x_offset), y: (@y + @block_size), w: (@block_size * 2), h: (@block_size), r: @r , g: @g, b: @b }
        elsif @orientation == :up
            #args.outputs.solids << [@x + x_offset, @y, @block_size * 3 - @block_offset, @block_size - @block_offset, @r, @g, @b]
            args.outputs.solids << {x: (@x + x_offset), y: (@y), w: (@block_size * 3 - @block_offset), h: (@block_size - @block_offset), r: @r , g: @g, b: @b}
            #args.outputs.solids << [@x + x_offset + @block_size, @y, @block_size, @block_size * 2, @r, @g, @b]
            args.outputs.solids << {x: (@x + x_offset + @block_size), y: (@y), w: (@block_size), h: (@block_size * 2), r: @r , g: @g, b: @b}
        elsif @orientation == :left
            #args.outputs.solids << [@x + x_offset + @block_size, @y, @block_size - @block_offset, @block_size * 3 - @block_offset, @r, @g, @b]
            args.outputs.solids << {x: (@x + x_offset + @block_size), y: (@y), w: (@block_size - @block_offset), h: (@block_size * 3 - @block_offset), r: @r , g: @g, b: @b}
            #args.outputs.solids << [@x + x_offset, @y + @block_size, @block_size * 2 - @block_offset, @block_size - @block_offset, @r, @g, @b]
            args.outputs.solids << {x: (@x + x_offset), y: (@y + @block_size), w: (@block_size * 2 - @block_offset), h: (@block_size - @block_offset), r: @r , g: @g, b: @b}
        elsif @orientation == :down
            #args.outputs.solids << [@x + x_offset, @y + @block_size, @block_size * 3 - @block_offset, @block_size - @block_offset, @r, @g, @b]
            args.outputs.solids << {x: (@x + x_offset), y: (@y + @block_size), w: (@block_size * 3 - @block_offset), h: (@block_size - @block_offset), r: @r , g: @g, b: @b}
            #args.outputs.solids << [@x + x_offset + @block_size, @y, @block_size - @block_offset, @block_size * 2 - @block_offset, @r, @g, @b]
            args.outputs.solids << {x: (@x + x_offset + @block_size), y: (@y), w: (@block_size - @block_offset), h: ( @block_size * 2 - @block_offset), r: @r , g: @g, b: @b}
        end

        #psize = 5.0
        #for p in @shapePoints
          #args.outputs.solids << [p.x-psize/2, p.y-psize/2, psize, psize, 0, 0, 0]
        #end
        args.outputs.labels << [@x + x_offset + (@block_size * 2 - @block_offset)/2, (@y) + (@block_size * 2 - @block_offset)/2, @count.to_s]

    end

    def updateOne_old args
      didHit = false
      hitter = nil
      toCollide = nil
      for b in args.state.balls
        if [b.x, b.y, b.width, b.height].intersect_rect?(@bold)
          didSquare = false
          for s in @squareColliders
            if (s.collision?(args, b))
              didSquare = true
              didHit = true
              #s.collide(args, b)
              toCollide = s
              hitter = b
              break
            end
          end
          if (didSquare == false)
            for c in @colliders
              #puts args.state.ball.velocity
              if c.collision?(args, b.getPoints(args),b)
                #c.collide args, b
                toCollide = c
                didHit = true
                hitter = b
                break
              end
            end
          end
        end
        if didHit
          break
        end
      end
      if (didHit)
        @count=0
        hitter.makeLeader args
        #toCollide.collide(args, hitter)
        args.state.tshapes.delete(self)
        #puts "HIT!" + hitter.number
      end
    end

    def update_old args
      if (@count == 1)
        updateOne args
        return
      end
      didHit = false
      hitter = nil
      for b in args.state.ballParents
        if [b.x, b.y, b.width, b.height].intersect_rect?(@bold)
          didSquare = false
          for s in @squareColliders
            if (s.collision?(args, b))
              didSquare = true
              didHit=true
              s.collide(args, b)
              hitter = b
            end
          end
          if (didSquare == false)
            for c in @colliders
              #puts args.state.ball.velocity
              if c.collision?(args, b.getPoints(args), b)
                c.collide args, b
                didHit=true
                hitter = b
              end
            end
          end
        end
      end
      if (didHit)
        @count=@count-1
        @damageCount.append([(hitter.leastChain+1 - hitter.number)-1, Kernel.tick_count])

        if (@count == 0)
          args.state.tshapes.delete(self)
          return
        end
      end
      i=0

      while i < @damageCount.length
        if @damageCount[i][0] <= 0
          @damageCount.delete_at(i)
          i-=1
        elsif @damageCount[i][1].elapsed_time > BALL_DISTANCE
          @count-=1
          @damageCount[i][0]-=1
        end
        if (@count == 0)
          args.state.tshapes.delete(self)
          return
        end
        i+=1
      end
    end #end update

    def update args
      universalUpdate args, self
    end

end

class Line
    attr_accessor :count, :x, :y, :home, :bold, :squareColliders, :colliders, :damageCount
    def initialize(args, x, y, block_size, orientation, block_offset)
        @x = x * block_size
        @y = y * block_size
        @block_size = block_size
        @block_offset = block_offset
        @orientation = orientation
        @damageCount = []
        @home = "lines"

        Kernel.srand()
        @r = rand(255)
        @g = rand(255)
        @b = rand(255)

        @count = rand(MAX_COUNT)+1

        @shapePoints = getShapePoints(args)
        minX={x:INFINITY, y:0}
        minY={x:0, y:INFINITY}
        maxX={x:-INFINITY, y:0}
        maxY={x:0, y:-INFINITY}
        for p in @shapePoints
          if p.x < minX.x
            minX = p
          end
          if p.x > maxX.x
            maxX = p
          end
          if p.y < minY.y
            minY = p
          end
          if p.y > maxY.y
            maxY = p
          end
        end


        hypotenuse=args.state.ball_hypotenuse

        @bold = [(minX.x-hypotenuse/2)-1, (minY.y-hypotenuse/2)-1, -((minX.x-hypotenuse/2)-1)+(maxX.x + hypotenuse + 2), -((minY.y-hypotenuse/2)-1)+(maxY.y + hypotenuse + 2)]
    end

    def getShapePoints(args)
      points=[]
      x_offset = (args.state.board_width + args.grid.w / 8) + (@block_offset / 2)

      if @orientation == :right
        #args.outputs.solids << [@x + x_offset, @y, @block_size * 3 - @block_offset, @block_size - @block_offset, @r, @g, @b]
        xa =@x + x_offset
        ya =@y
        wa =@block_size * 3 - @block_offset
        ha =(@block_size - @block_offset)
      elsif @orientation == :up
        #args.outputs.solids << [@x + x_offset, @y, @block_size - @block_offset, @block_size * 3 - @block_offset, @r, @g, @b]
        xa =@x + x_offset
        ya =@y
        wa =@block_size - @block_offset
        ha =@block_size * 3 - @block_offset

      elsif @orientation == :left
        #args.outputs.solids << [@x + x_offset, @y, @block_size * 3 - @block_offset, @block_size - @block_offset, @r, @g, @b]
        xa =@x + x_offset
        ya =@y
        wa =@block_size * 3 - @block_offset
        ha =@block_size - @block_offset
      elsif @orientation == :down
        #args.outputs.solids << [@x + x_offset, @y, @block_size - @block_offset, @block_size * 3 - @block_offset, @r, @g, @b]
        xa =@x + x_offset
        ya =@y
        wa =@block_size - @block_offset
        ha =@block_size * 3 - @block_offset
      end
      points = [
        {x: xa, y:ya},
        {x: xa + wa,y:ya},
        {x: xa + wa,y:ya+ha},
        {x: xa, y:ya+ha},
      ]
      @squareColliders = [
        SquareCollider.new(points[0].x,points[0].y,{x:-1,y:-1}),
        SquareCollider.new(points[1].x-COLLISIONWIDTH,points[1].y,{x:1,y:-1}),
        SquareCollider.new(points[2].x-COLLISIONWIDTH,points[2].y-COLLISIONWIDTH,{x:1,y:1}),
        SquareCollider.new(points[3].x,points[3].y-COLLISIONWIDTH,{x:-1,y:1}),
      ]
      @colliders = [
        LinearCollider.new(points[0],points[1], :neg),
        LinearCollider.new(points[1],points[2], :neg),
        LinearCollider.new(points[2],points[3], :pos),
        LinearCollider.new(points[0],points[3], :pos),
      ]
      return points
    end

    def update args
      universalUpdate args, self
    end

    def draw(args)
        x_offset = (args.state.board_width + args.grid.w / 8) + @block_offset / 2

        if @orientation == :right
            args.outputs.solids << [@x + x_offset, @y, @block_size * 3 - @block_offset, @block_size - @block_offset, @r, @g, @b]
        elsif @orientation == :up
            args.outputs.solids << [@x + x_offset, @y, @block_size - @block_offset, @block_size * 3 - @block_offset, @r, @g, @b]
        elsif @orientation == :left
            args.outputs.solids << [@x + x_offset, @y, @block_size * 3 - @block_offset, @block_size - @block_offset, @r, @g, @b]
        elsif @orientation == :down
            args.outputs.solids << [@x + x_offset, @y, @block_size - @block_offset, @block_size * 3 - @block_offset, @r, @g, @b]
        end

        args.outputs.labels << [@x + x_offset + (@block_size * 2 - @block_offset)/2, (@y) + (@block_size * 2 - @block_offset)/2, @count.to_s]

    end
end

Arbitrary Collision - linear_collider.rb link

# ./samples/04_physics_and_collisions/09_arbitrary_collision/app/linear_collider.rb

COLLISIONWIDTH=8

class LinearCollider
  attr_reader :pointA, :pointB
  def initialize (pointA, pointB, mode,collisionWidth=COLLISIONWIDTH)
    @pointA = pointA
    @pointB = pointB
    @mode = mode
    @collisionWidth = collisionWidth

    if (@pointA.x > @pointB.x)
      @pointA, @pointB = @pointB, @pointA
    end

    @linearCollider_collision_once = false
  end

  def collisionSlope args
    if (@[email protected] == 0)
      return INFINITY
    end
    return (@pointB.y - @pointA.y) / (@pointB.x - @pointA.x)
  end


  def collision? (args, points, ball=nil)

    slope = collisionSlope args
    result = false

    # calculate a vector with a magnitude of (1/2)collisionWidth and a direction perpendicular to the collision line
    vect=nil;mag=nil;vect=nil;
    if @mode == :both
      vect = {x: @pointB.x - @pointA.x, y:@pointB.y - @pointA.y}
      mag  = (vect.x**2 + vect.y**2)**0.5
      vect = {y: -1*(vect.x/(mag))*@collisionWidth*0.5, x: (vect.y/(mag))*@collisionWidth*0.5}
    else
      vect = {x: @pointB.x - @pointA.x, y:@pointB.y - @pointA.y}
      mag  = (vect.x**2 + vect.y**2)**0.5
      vect = {y: -1*(vect.x/(mag))*@collisionWidth, x: (vect.y/(mag))*@collisionWidth}
    end

    rpointA=nil;rpointB=nil;rpointC=nil;rpointD=nil;
    if @mode == :pos
      rpointA = {x:@pointA.x + vect.x, y:@pointA.y + vect.y}
      rpointB = {x:@pointB.x + vect.x, y:@pointB.y + vect.y}
      rpointC = {x:@pointB.x, y:@pointB.y}
      rpointD = {x:@pointA.x, y:@pointA.y}
    elsif @mode == :neg
      rpointA = {x:@pointA.x, y:@pointA.y}
      rpointB = {x:@pointB.x, y:@pointB.y}
      rpointC = {x:@pointB.x - vect.x, y:@pointB.y - vect.y}
      rpointD = {x:@pointA.x - vect.x, y:@pointA.y - vect.y}
    elsif @mode == :both
      rpointA = {x:@pointA.x + vect.x, y:@pointA.y + vect.y}
      rpointB = {x:@pointB.x + vect.x, y:@pointB.y + vect.y}
      rpointC = {x:@pointB.x - vect.x, y:@pointB.y - vect.y}
      rpointD = {x:@pointA.x - vect.x, y:@pointA.y - vect.y}
    end
    #four point rectangle



    if ball != nil
      xs = [rpointA.x,rpointB.x,rpointC.x,rpointD.x]
      ys = [rpointA.y,rpointB.y,rpointC.y,rpointD.y]
      correct = 1
      rect1 = [ball.x, ball.y, ball.width, ball.height]
      #$r1 = rect1
      rect2 = [xs.min-correct,ys.min-correct,(xs.max-xs.min)+correct*2,(ys.max-ys.min)+correct*2]
      #$r2 = rect2
      if rect1.intersect_rect?(rect2) == false
        return false
      end
    end


    #area of a triangle
    triArea = -> (a,b,c) { ((a.x * (b.y - c.y) + b.x * (c.y - a.y) + c.x * (a.y - b.y))/2.0).abs }

    #if at least on point is in the rectangle then collision? is true - otherwise false
    for point in points
      #Check whether a given point lies inside a rectangle or not:
      #if the sum of the area of traingls, PAB, PBC, PCD, PAD equal the area of the rec, then an intersection has occured
      areaRec =  triArea.call(rpointA, rpointB, rpointC)+triArea.call(rpointA, rpointC, rpointD)
      areaSum = [
        triArea.call(point, rpointA, rpointB),triArea.call(point, rpointB, rpointC),
        triArea.call(point, rpointC, rpointD),triArea.call(point, rpointA, rpointD)
      ].inject(0){|sum,x| sum + x }
      e = 0.0001 #allow for minor error
      if areaRec>= areaSum-e and areaRec<= areaSum+e
        result = true
        #return true
        break
      end
    end

    #args.outputs.lines << [@pointA.x, @pointA.y, @pointB.x, @pointB.y,     000, 000, 000]
    #args.outputs.lines << [rpointA.x, rpointA.y, rpointB.x, rpointB.y,     255, 000, 000]
    #args.outputs.lines << [rpointC.x, rpointC.y, rpointD.x, rpointD.y,     000, 000, 255]


    #puts (rpointA.x.to_s + " " +  rpointA.y.to_s + " " + rpointB.x.to_s + " "+ rpointB.y.to_s)
    return result
  end #end collision?

  def getRepelMagnitude (fbx, fby, vrx, vry, ballMag)
    a = fbx ; b = vrx ; c = fby
    d = vry ; e = ballMag
    if b**2 + d**2 == 0
      #unexpected
    end
    x1 = (-a*b+-c*d + (e**2 * b**2 - b**2 * c**2 + 2*a*b*c*d + e**2 + d**2 - a**2 * d**2)**0.5)/(b**2 + d**2)
    x2 = -((a*b + c*d + (e**2 * b**2 - b**2 * c**2 + 2*a*b*c*d + e**2 * d**2 - a**2 * d**2)**0.5)/(b**2 + d**2))
    err = 0.00001
    o = ((fbx + x1*vrx)**2 + (fby + x1*vry)**2 ) ** 0.5
    p = ((fbx + x2*vrx)**2 + (fby + x2*vry)**2 ) ** 0.5
    r = 0
    if (ballMag >= o-err and ballMag <= o+err)
      r = x1
    elsif (ballMag >= p-err and ballMag <= p+err)
      r = x2
    else
      #unexpected
    end
    return r
  end

  def collide args, ball
    slope = collisionSlope args

    # perpVect: normal vector perpendicular to collision
    perpVect = {x: @pointB.x - @pointA.x, y:@pointB.y - @pointA.y}
    mag  = (perpVect.x**2 + perpVect.y**2)**0.5
    perpVect = {x: perpVect.x/(mag), y: perpVect.y/(mag)}
    perpVect = {x: -perpVect.y, y: perpVect.x}
    if perpVect.y > 0 #ensure perpVect points upward
      perpVect = {x: perpVect.x*-1, y: perpVect.y*-1}
    end
    previousPosition = {
      x:ball.x-ball.velocity.x,
      y:ball.y-ball.velocity.y
    }
    yInterc = @pointA.y + -slope*@pointA.x
    if slope == INFINITY
      if previousPosition.x < @pointA.x
        perpVect = {x: perpVect.x*-1, y: perpVect.y*-1}
        yInterc = -INFINITY
      end
    elsif previousPosition.y < slope*previousPosition.x + yInterc #check if ball is bellow or above the collider to determine if perpVect is - or +
      perpVect = {x: perpVect.x*-1, y: perpVect.y*-1}
    end

    velocityMag = (ball.velocity.x**2 + ball.velocity.y**2)**0.5
    theta_ball=Math.atan2(ball.velocity.y,ball.velocity.x) #the angle of the ball's velocity
    theta_repel=Math.atan2(perpVect.y,perpVect.x) #the angle of the repelling force(perpVect)

    fbx = velocityMag * Math.cos(theta_ball) #the x component of the ball's velocity
    fby = velocityMag * Math.sin(theta_ball) #the y component of the ball's velocity

    #the magnitude of the repelling force
    repelMag = getRepelMagnitude(fbx, fby, perpVect.x, perpVect.y, (ball.velocity.x**2 + ball.velocity.y**2)**0.5)
    frx = repelMag* Math.cos(theta_repel) #the x component of the repel's velocity | magnitude is set to twice of fbx
    fry = repelMag* Math.sin(theta_repel) #the y component of the repel's velocity | magnitude is set to twice of fby

    fsumx = fbx+frx #sum of x forces
    fsumy = fby+fry #sum of y forces
    fr = velocityMag#fr is the resulting magnitude
    thetaNew = Math.atan2(fsumy, fsumx)  #thetaNew is the resulting angle
    xnew = fr*Math.cos(thetaNew)#resulting x velocity
    ynew = fr*Math.sin(thetaNew)#resulting y velocity
    if (velocityMag < MAX_VELOCITY)
      ball.velocity =  Vector2d.new(xnew*1.1, ynew*1.1)
    else
      ball.velocity =  Vector2d.new(xnew, ynew)
    end

  end
end

Arbitrary Collision - main.rb link

# ./samples/04_physics_and_collisions/09_arbitrary_collision/app/main.rb
INFINITY= 10**10
MAX_VELOCITY = 8.0
BALL_COUNT = 90
BALL_DISTANCE = 20
require 'app/vector2d.rb'
require 'app/blocks.rb'
require 'app/ball.rb'
require 'app/rectangle.rb'
require 'app/linear_collider.rb'
require 'app/square_collider.rb'



#Method to init default values
def defaults args
  args.state.board_width ||= args.grid.w / 4
  args.state.board_height ||= args.grid.h
  args.state.game_area ||= [(args.state.board_width + args.grid.w / 8), 0, args.state.board_width, args.grid.h]
  args.state.balls ||= []
  args.state.num_balls ||= 0
  args.state.ball_created_at ||= Kernel.tick_count
  args.state.ball_hypotenuse = (10**2 + 10**2)**0.5
  args.state.ballParents ||= []

  init_blocks args
  init_balls args
end

begin :default_methods
  def init_blocks args
    block_size = args.state.board_width / 8
    #Space inbetween each block
    block_offset = 4

    args.state.squares ||=[
      Square.new(args, 2, 0, block_size, :right, block_offset),
      Square.new(args, 5, 0, block_size, :right, block_offset),
      Square.new(args, 6, 7, block_size, :right, block_offset)
    ]


    #Possible orientations are :right, :left, :up, :down


    args.state.tshapes ||= [
      TShape.new(args, 0, 6, block_size, :left, block_offset),
      TShape.new(args, 3, 3, block_size, :down, block_offset),
      TShape.new(args, 0, 3, block_size, :right, block_offset),
      TShape.new(args, 0, 11, block_size, :up, block_offset)
    ]

    args.state.lines ||= [
      Line.new(args,3, 8, block_size, :down, block_offset),
      Line.new(args, 7, 3, block_size, :up, block_offset),
      Line.new(args, 3, 7, block_size, :right, block_offset)
    ]

    #exit()
  end

  def init_balls args
    return unless args.state.num_balls < BALL_COUNT


    #only create a new ball every 10 ticks
    return unless args.state.ball_created_at.elapsed_time > 10

    if (args.state.num_balls == 0)
      args.state.balls.append(Ball.new(args,args.state.num_balls,BALL_COUNT-1, nil, nil))
      args.state.ballParents = [args.state.balls[0]]
    else
      args.state.balls.append(Ball.new(args,args.state.num_balls,BALL_COUNT-1, args.state.balls.last, nil) )
      args.state.balls[-2].child = args.state.balls[-1]
    end
    args.state.ball_created_at = Kernel.tick_count
    args.state.num_balls += 1
  end
end

#Render loop
def render args
  bgClr = {r:10, g:10, b:200}
  bgClr = {r:255-30, g:255-30, b:255-30}

  args.outputs.solids << [0, 0, $args.grid.right, $args.grid.top, bgClr[:r], bgClr[:g], bgClr[:b]];
  args.outputs.borders << args.state.game_area

  render_instructions args
  render_shapes args

  render_balls args

  #args.state.rectangle.draw args

  args.outputs.sprites << [$args.grid.right-(args.state.board_width + args.grid.w / 8), 0, $args.grid.right, $args.grid.top, "sprites/square-white-2.png", 0, 255, bgClr[:r], bgClr[:g], bgClr[:b]]
  args.outputs.sprites << [0, 0, (args.state.board_width + args.grid.w / 8), $args.grid.top, "sprites/square-white-2.png", 0, 255, bgClr[:r], bgClr[:g], bgClr[:b]]

end

begin :render_methods
  def render_instructions args
    #gtk.current_framerate
    args.outputs.labels << [20, $args.grid.top-20, "FPS: " + $gtk.current_framerate.to_s]
    if (args.state.balls != nil && args.state.balls[0] != nil)
        bx =  args.state.balls[0].velocity.x
        by =  args.state.balls[0].velocity.y
        bmg = (bx**2.0 + by**2.0)**0.5
        args.outputs.labels << [20, $args.grid.top-20-20, "V: " + bmg.to_s ]
    end


  end

  def render_shapes args
    for s in args.state.squares
      s.draw args
    end

    for l in args.state.lines
      l.draw args
    end

    for t in args.state.tshapes
      t.draw args
    end


  end

  def render_balls args
    #args.state.balls.each do |ball|
      #ball.draw args
    #end

    args.outputs.sprites << args.state.balls.map do |ball|
      ball.getDraw args
    end
  end
end

#Calls all methods necessary for performing calculations
def calc args
  for b in args.state.ballParents
    b.update args
  end

  for s in args.state.squares
    s.update args
  end

  for l in args.state.lines
    l.update args
  end

  for t in args.state.tshapes
    t.update args
  end



end

begin :calc_methods

end

def tick args
  defaults args
  render args
  calc args
end

Arbitrary Collision - paddle.rb link

# ./samples/04_physics_and_collisions/09_arbitrary_collision/app/paddle.rb
class Paddle
  attr_accessor :enabled

  def initialize ()
    @x=WIDTH/2
    @y=100
    @width=100
    @height=20
    @speed=10

    @xyCollision  = LinearCollider.new({x: @x,y: @y+@height+5}, {x: @x+@width, y: @y+@height+5})
    @xyCollision2 = LinearCollider.new({x: @x,y: @y}, {x: @x+@width, y: @y}, :pos)
    @xyCollision3 = LinearCollider.new({x: @x,y: @y}, {x: @x, y: @y+@height+5})
    @xyCollision4 = LinearCollider.new({x: @x+@width,y: @y}, {x: @x+@width, y: @y+@height+5}, :pos)

    @enabled = true
  end

  def update args
    @xyCollision.resetPoints({x: @x,y: @y+@height+5}, {x: @x+@width, y: @y+@height+5})
    @xyCollision2.resetPoints({x: @x,y: @y}, {x: @x+@width, y: @y})
    @xyCollision3.resetPoints({x: @x,y: @y}, {x: @x, y: @y+@height+5})
    @xyCollision4.resetPoints({x: @x+@width,y: @y}, {x: @x+@width, y: @y+@height+5})

    @xyCollision.update  args
    @xyCollision2.update args
    @xyCollision3.update args
    @xyCollision4.update args

    args.inputs.keyboard.key_held.left  ||= false
    args.inputs.keyboard.key_held.right  ||= false

    if not (args.inputs.keyboard.key_held.left == args.inputs.keyboard.key_held.right)
      if args.inputs.keyboard.key_held.left && @enabled
        @x-=@speed
      elsif args.inputs.keyboard.key_held.right && @enabled
        @x+=@speed
      end
    end

    xmin =WIDTH/4
    xmax = 3*(WIDTH/4)
    @x = (@x+@width > xmax) ? xmax-@width : (@x<xmin) ? xmin : @x;
  end

  def render args
    args.outputs.solids << [@x,@y,@width,@height,255,0,0];
  end

  def rect
    [@x, @y, @width, @height]
  end
end

Arbitrary Collision - rectangle.rb link

# ./samples/04_physics_and_collisions/09_arbitrary_collision/app/rectangle.rb
class Rectangle
  def initialize args

    @image = "sprites/roundSquare_white.png"
    @width  = 160.0
    @height = 80.0
    @x=$args.grid.right/2.0 - @width/2.0
    @y=$args.grid.top/2.0 - @height/2.0

    @xtmp = @width  * (1.0/10.0)
    @ytmp = @height * (1.0/10.0)

    #ball0 = args.state.balls[0]
    #hypotenuse = (args.state.balls[0].width**2 + args.state.balls[0].height**2)**0.5
    hypotenuse=args.state.ball_hypotenuse
    @boldXY = {x:(@x-hypotenuse/2)-1, y:(@y-hypotenuse/2)-1}
    @boldWidth = @width + hypotenuse + 2
    @boldHeight = @height + hypotenuse + 2
    @bold = [(@x-hypotenuse/2)-1,(@y-hypotenuse/2)-1,@width + hypotenuse + 2,@height + hypotenuse + 2]


    @points = [
      {x:@x,        y:@y+@ytmp},
      {x:@x+@xtmp,        y:@y},
      {x:@x+@width-@xtmp, y:@y},
      {x:@x+@width, y:@y+@ytmp},
      {x:@x+@width, y:@y+@height-@ytmp},#
      {x:@x+@width-@xtmp, y:@y+@height},
      {x:@x+@xtmp,        y:@y+@height},
      {x:@x,        y:@y+@height-@ytmp}
    ]

    @colliders = []
    #i = 0
    #while i < @points.length-1
      #@colliders.append(LinearCollider.new(@points[i],@points[i+1],:pos))
      #i+=1
    #end
    @colliders.append(LinearCollider.new(@points[0],@points[1], :neg))
    @colliders.append(LinearCollider.new(@points[1],@points[2], :neg))
    @colliders.append(LinearCollider.new(@points[2],@points[3], :neg))
    @colliders.append(LinearCollider.new(@points[3],@points[4], :neg))
    @colliders.append(LinearCollider.new(@points[4],@points[5], :pos))
    @colliders.append(LinearCollider.new(@points[5],@points[6], :pos))
    @colliders.append(LinearCollider.new(@points[6],@points[7], :pos))
    @colliders.append(LinearCollider.new(@points[0],@points[7], :pos))

  end

  def update args

    for b in args.state.balls
      if [b.x, b.y, b.width, b.height].intersect_rect?(@bold)
        for c in @colliders
          if c.collision?(args, b.getPoints(args),b)
            c.collide args, b
          end
        end
      end
    end
  end

  def draw args
    args.outputs.sprites << [
      @x,                                       # X
      @y,                                       # Y
      @width,                                   # W
      @height,                                  # H
      @image,                                   # PATH
      0,                                        # ANGLE
      255,                                      # ALPHA
      219,                                      # RED_SATURATION
      112,                                      # GREEN_SATURATION
      147                                       # BLUE_SATURATION
    ]
    #args.outputs.sprites << [@x, @y, @width, @height, "sprites/roundSquare_small_black.png"]
  end

  def serialize
  	{x: @x, y:@y}
  end

  def inspect
  	serialize.to_s
  end

  def to_s
  	serialize.to_s
  end
end

Arbitrary Collision - square_collider.rb link

# ./samples/04_physics_and_collisions/09_arbitrary_collision/app/square_collider.rb

class SquareCollider
  def initialize x,y,direction,size=COLLISIONWIDTH
    @x = x
    @y = y
    @size = size
    @direction = direction

  end
  def collision? args, ball
    #args.outputs.solids <<  [@x, @y, @size, @size,     000, 255, 255]


    return [@x,@y,@size,@size].intersect_rect?([ball.x,ball.y,ball.width,ball.height])
  end

  def collide args, ball
    vmag = (ball.velocity.x**2.0 +ball.velocity.y**2.0)**0.5
    a = ((2.0**0.5)*vmag)/2.0
    if vmag < MAX_VELOCITY
      ball.velocity.x = (a) * @direction.x * 1.1
      ball.velocity.y = (a) * @direction.y * 1.1
    else
      ball.velocity.x = (a) * @direction.x
      ball.velocity.y = (a) * @direction.y
    end

  end
end

Arbitrary Collision - vector2d.rb link

# ./samples/04_physics_and_collisions/09_arbitrary_collision/app/vector2d.rb
class Vector2d
    attr_accessor :x, :y

    def initialize x=0, y=0
      @x=x
      @y=y
    end

    #returns a vector multiplied by scalar x
    #x [float] scalar
    def mult x
      r = Vector2d.new(0,0)
      r.x=@x*x
      r.y=@y*x
      r
    end

    # vect [Vector2d] vector to copy
    def copy vect
      Vector2d.new(@x, @y)
    end

    #returns a new vector equivalent to this+vect
    #vect [Vector2d] vector to add to self
    def add vect
      Vector2d.new(@x+vect.x,@y+vect.y)
    end

    #returns a new vector equivalent to this-vect
    #vect [Vector2d] vector to subtract to self
    def sub vect
      Vector2d.new(@x-vect.c, @y-vect.y)
    end

    #return the magnitude of the vector
    def mag
      ((@x**2)+(@y**2))**0.5
    end

    #returns a new normalize version of the vector
    def normalize
      Vector2d.new(@x/mag, @y/mag)
    end

    #TODO delet?
    def distABS vect
      (((vect.x-@x)**2+(vect.y-@y)**2)**0.5).abs()
    end
  end

Collision With Object Removal - ball.rb link

# ./samples/04_physics_and_collisions/10_collision_with_object_removal/app/ball.rb
class Ball
  #TODO limit accessors?
  attr_accessor :xy, :width, :height, :velocity


  #@xy [Vector2d] x,y position
  #@velocity [Vector2d] velocity of ball
  def initialize
    @xy = Vector2d.new(WIDTH/2,500)
    @velocity = Vector2d.new(4,-4)
    @width =  20
    @height = 20
  end

  #move the ball according to its velocity
  def update args
    @[email protected]
    @[email protected]
  end

  #render the ball to the screen
  def render args
    args.outputs.solids << [@xy.x,@xy.y,@width,@height,255,0,255];
    #args.outputs.labels << [20,HEIGHT-50,"velocity: " [email protected]_s+","[email protected]_s + "   magnitude:" + @velocity.mag.to_s]
  end

  def rect
    [@xy.x,@xy.y,@width,@height]
  end

end

Collision With Object Removal - linear_collider.rb link

# ./samples/04_physics_and_collisions/10_collision_with_object_removal/app/linear_collider.rb
#The LinearCollider (theoretically) produces collisions upon a line segment defined point.y two x,y cordinates

class LinearCollider

  #start [Array of length 2] start of the line segment as a x,y cordinate
  #last [Array of length 2] end of the line segment as a x,y cordinate

  #inorder for the LinearCollider to be functional the line segment must be said to have a thickness
  #(as it is unlikly that a colliding object will land exactly on the linesegment)

  #extension defines if the line's thickness extends negatively or positively
  #extension :pos     extends positively
  #extension :neg     extends negatively

  #thickness [float] how thick the line should be (should always be atleast as large as the magnitude of the colliding object)
  def initialize (pointA, pointB, extension=:neg, thickness=10)
    @pointA = pointA
    @pointB = pointB
    @thickness = thickness
    @extension = extension

    @pointAExtended={
      x: @pointA.x + @thickness*(@extension == :neg ? -1 : 1),
      y: @pointA.y + @thickness*(@extension == :neg ? -1 : 1)
    }
    @pointBExtended={
      x: @pointB.x + @thickness*(@extension == :neg ? -1 : 1),
      y: @pointB.y + @thickness*(@extension == :neg ? -1 : 1)
    }

  end

  def resetPoints(pointA,pointB)
    @pointA = pointA
    @pointB = pointB

    @pointAExtended={
      x:@pointA.x + @thickness*(@extension == :neg ? -1 : 1),
      y:@pointA.y + @thickness*(@extension == :neg ? -1 : 1)
    }
    @pointBExtended={
      x:@pointB.x + @thickness*(@extension == :neg ? -1 : 1),
      y:@pointB.y + @thickness*(@extension == :neg ? -1 : 1)
    }
  end

  #TODO: Ugly function
  def slope (pointA, pointB)
    return (pointB.x==pointA.x) ? INFINITY : (pointB.y+-pointA.y)/(pointB.x+-pointA.x)
  end

  #TODO: Ugly function
  def intercept(pointA, pointB)
    if (slope(pointA, pointB) == INFINITY)
      -INFINITY
    elsif slope(pointA, pointB) == -1*INFINITY
      INFINITY
    else
      pointA.y+-1.0*(slope(pointA, pointB)*pointA.x)
    end
  end

  def calcY(pointA, pointB, x)
    return slope(pointA, pointB)*x + intercept(pointA, pointB)
  end

  #test if a collision has occurred
  def isCollision? (point)
    #INFINITY slop breaks down when trying to determin collision, ergo it requires a special test
    if slope(@pointA, @pointB) ==  INFINITY &&
      point.x >= [@pointA.x,@pointB.x].min+(@extension == :pos ? -@thickness : 0) &&
      point.x <= [@pointA.x,@pointB.x].max+(@extension == :neg ?  @thickness : 0) &&
      point.y >= [@pointA.y,@pointB.y].min && point.y <= [@pointA.y,@pointB.y].max
        return true
    end

    isNegInLine   = @extension == :neg &&
                    point.y <= slope(@pointA, @pointB)*point.x+intercept(@pointA,@pointB) &&
                    point.y >= point.x*slope(@pointAExtended, @pointBExtended)+intercept(@pointAExtended,@pointBExtended)
    isPosInLine   = @extension == :pos &&
                    point.y >= slope(@pointA, @pointB)*point.x+intercept(@pointA,@pointB) &&
                    point.y <= point.x*slope(@pointAExtended, @pointBExtended)+intercept(@pointAExtended,@pointBExtended)
    isInBoxBounds = point.x >= [@pointA.x,@pointB.x].min &&
                    point.x <= [@pointA.x,@pointB.x].max &&
                    point.y >= [@pointA.y,@pointB.y].min+(@extension == :neg ? -@thickness : 0) &&
                    point.y <= [@pointA.y,@pointB.y].max+(@extension == :pos ? @thickness : 0)

    return isInBoxBounds && (isNegInLine || isPosInLine)

  end

  def getRepelMagnitude (fbx, fby, vrx, vry, args)
    a = fbx ; b = vrx ; c = fby
    d = vry ; e = args.state.ball.velocity.mag

    if b**2 + d**2 == 0
      puts "magnitude error"
    end

    x1 = (-a*b+-c*d + (e**2 * b**2 - b**2 * c**2 + 2*a*b*c*d + e**2 + d**2 - a**2 * d**2)**0.5)/(b**2 + d**2)
    x2 = -((a*b + c*d + (e**2 * b**2 - b**2 * c**2 + 2*a*b*c*d + e**2 * d**2 - a**2 * d**2)**0.5)/(b**2 + d**2))
    return ((a+x1*b)**2 + (c+x1*d)**2 == e**2) ? x1 : x2
  end

  def update args
    #each of the four points on the square ball - NOTE simple to extend to a circle
    points= [ {x: args.state.ball.xy.x,                          y: args.state.ball.xy.y},
              {x: args.state.ball.xy.x+args.state.ball.width,    y: args.state.ball.xy.y},
              {x: args.state.ball.xy.x,                          y: args.state.ball.xy.y+args.state.ball.height},
              {x: args.state.ball.xy.x+args.state.ball.width,    y: args.state.ball.xy.y + args.state.ball.height}
            ]

    #for each point p in points
    for point in points
      #isCollision.md has more information on this section
      #TODO: section can certainly be simplifyed
      if isCollision?(point)
        u = Vector2d.new(1.0,((slope(@pointA, @pointB)==0) ? INFINITY : -1/slope(@pointA, @pointB))*1.0).normalize #normal perpendicular (to line segment) vector

        #the vector with the repeling force can be u or -u depending of where the ball was coming from in relation to the line segment
        previousBallPosition=Vector2d.new(point.x-args.state.ball.velocity.x,point.y-args.state.ball.velocity.y)
        choiceA = (u.mult(1))
        choiceB =  (u.mult(-1))
        vectorRepel = nil

        if (slope(@pointA, @pointB))!=INFINITY && u.y < 0
          choiceA, choiceB = choiceB, choiceA
        end
        vectorRepel = (previousBallPosition.y > calcY(@pointA, @pointB, previousBallPosition.x)) ? choiceA : choiceB

        #vectorRepel = (previousBallPosition.y > slope(@pointA, @pointB)*previousBallPosition.x+intercept(@pointA,@pointB)) ? choiceA : choiceB)
        if (slope(@pointA, @pointB) == INFINITY) #slope INFINITY breaks down in the above test, ergo it requires a custom test
          vectorRepel = (previousBallPosition.x > @pointA.x) ? (u.mult(1)) : (u.mult(-1))
        end
        #puts ("     " + $t[0].to_s + "," + $t[1].to_s + "    " + $t[2].to_s + "," + $t[3].to_s + "     " + "   " + u.x.to_s + "," + u.y.to_s)
        #vectorRepel now has the repeling force

        mag = args.state.ball.velocity.mag
        theta_ball=Math.atan2(args.state.ball.velocity.y,args.state.ball.velocity.x) #the angle of the ball's velocity
        theta_repel=Math.atan2(vectorRepel.y,vectorRepel.x) #the angle of the repeling force
        #puts ("theta:" + theta_ball.to_s + " " + theta_repel.to_s) #theta okay

        fbx = mag * Math.cos(theta_ball) #the x component of the ball's velocity
        fby = mag * Math.sin(theta_ball) #the y component of the ball's velocity

        repelMag = getRepelMagnitude(fbx, fby, vectorRepel.x, vectorRepel.y, args)

        frx = repelMag* Math.cos(theta_repel) #the x component of the repel's velocity | magnitude is set to twice of fbx
        fry = repelMag* Math.sin(theta_repel) #the y component of the repel's velocity | magnitude is set to twice of fby

        fsumx = fbx+frx #sum of x forces
        fsumy = fby+fry #sum of y forces
        fr = mag#fr is the resulting magnitude
        thetaNew = Math.atan2(fsumy, fsumx)  #thetaNew is the resulting angle
        xnew = fr*Math.cos(thetaNew) #resulting x velocity
        ynew = fr*Math.sin(thetaNew) #resulting y velocity

        args.state.ball.velocity = Vector2d.new(xnew,ynew)
        #args.state.ball.xy.add(args.state.ball.velocity)
        break #no need to check the other points ?
      else
      end
    end
  end #end update

end

Collision With Object Removal - main.rb link

# ./samples/04_physics_and_collisions/10_collision_with_object_removal/app/main.rb
# coding: utf-8
INFINITY= 10**10
WIDTH=1280
HEIGHT=720

require 'app/vector2d.rb'
require 'app/paddle.rb'
require 'app/ball.rb'
require 'app/linear_collider.rb'

#Method to init default values
def defaults args
  args.state.game_board ||= [(args.grid.w / 2 - args.grid.w / 4), 0, (args.grid.w / 2), args.grid.h]
  args.state.bricks ||= []
  args.state.num_bricks ||= 0
  args.state.game_over_at ||= 0
  args.state.paddle ||= Paddle.new
  args.state.ball   ||= Ball.new
  args.state.westWall  ||= LinearCollider.new({x: args.grid.w/4,      y: 0},          {x: args.grid.w/4,      y: args.grid.h}, :pos)
  args.state.eastWall  ||= LinearCollider.new({x: 3*args.grid.w*0.25, y: 0},          {x: 3*args.grid.w*0.25, y: args.grid.h})
  args.state.southWall ||= LinearCollider.new({x: 0,                  y: 0},          {x: args.grid.w,        y: 0})
  args.state.northWall ||= LinearCollider.new({x: 0,                  y:args.grid.h}, {x: args.grid.w,        y: args.grid.h}, :pos)

  #args.state.testWall ||= LinearCollider.new({x:0 , y:0},{x:args.grid.w, y:args.grid.h})
end

#Render loop
def render args
  render_instructions args
  render_board args
  render_bricks args
end

begin :render_methods
  #Method to display the instructions of the game
  def render_instructions args
    args.outputs.labels << [225, args.grid.h - 30, "← and → to move the paddle left and right",  0, 1]
  end

  def render_board args
    args.outputs.borders << args.state.game_board
  end

  def render_bricks args
    args.outputs.solids << args.state.bricks.map(&:rect)
  end
end

#Calls all methods necessary for performing calculations
def calc args
  add_new_bricks args
  reset_game args
  calc_collision args
  win_game args

  args.state.westWall.update args
  args.state.eastWall.update args
  args.state.southWall.update args
  args.state.northWall.update args
  args.state.paddle.update args
  args.state.ball.update args

  #args.state.testWall.update args

  args.state.paddle.render args
  args.state.ball.render args
end

begin :calc_methods
  def add_new_bricks args
    return if args.state.num_bricks > 40

    #Width of the game board is 640px
    brick_width = (args.grid.w / 2) / 10
    brick_height = brick_width / 2

    (4).map_with_index do |y|
      #Make a box that is 10 bricks wide and 4 bricks tall
      args.state.bricks += (10).map_with_index do |x|
        args.state.new_entity(:brick) do |b|
          b.x = x * brick_width + (args.grid.w / 2 - args.grid.w / 4)
          b.y = args.grid.h - ((y + 1) * brick_height)
          b.rect = [b.x + 1, b.y - 1, brick_width - 2, brick_height - 2, 235, 50 * y, 52]

          #Add linear colliders to the brick
          b.collider_bottom = LinearCollider.new([(b.x-2), (b.y-5)], [(b.x+brick_width+1), (b.y-5)], :pos, brick_height)
          b.collider_right = LinearCollider.new([(b.x+brick_width+1), (b.y-5)], [(b.x+brick_width+1), (b.y+brick_height+1)], :pos)
          b.collider_left = LinearCollider.new([(b.x-2), (b.y-5)], [(b.x-2), (b.y+brick_height+1)], :neg)
          b.collider_top = LinearCollider.new([(b.x-2), (b.y+brick_height+1)], [(b.x+brick_width+1), (b.y+brick_height+1)], :neg)

          # @xyCollision  = LinearCollider.new({x: @x,y: @y+@height}, {x: @x+@width, y: @y+@height})
          # @xyCollision2 = LinearCollider.new({x: @x,y: @y}, {x: @x+@width, y: @y}, :pos)
          # @xyCollision3 = LinearCollider.new({x: @x,y: @y}, {x: @x, y: @y+@height})
          # @xyCollision4 = LinearCollider.new({x: @x+@width,y: @y}, {x: @x+@width, y: @y+@height}, :pos)

          b.broken = false

          args.state.num_bricks += 1
        end
      end
    end
  end

  def reset_game args
    if args.state.ball.xy.y < 20 && args.state.game_over_at.elapsed_time > 60
      #Freeze the ball
      args.state.ball.velocity.x = 0
      args.state.ball.velocity.y = 0
      #Freeze the paddle
      args.state.paddle.enabled = false

      args.state.game_over_at = Kernel.tick_count
    end

    if args.state.game_over_at.elapsed_time < 60 && Kernel.tick_count > 60 && args.state.bricks.count != 0
      #Display a "Game over" message
      args.outputs.labels << [100, 100, "GAME OVER", 10]
    end

    #If 60 frames have passed since the game ended, restart the game
    if args.state.game_over_at != 0 && args.state.game_over_at.elapsed_time == 60
      # FIXME: only put value types in state
      args.state.ball = Ball.new

      # FIXME: only put value types in state
      args.state.paddle = Paddle.new

      args.state.bricks = []
      args.state.num_bricks = 0
    end
  end

  def calc_collision args
    #Remove the brick if it is hit with the ball
    ball = args.state.ball
    ball_rect = [ball.xy.x, ball.xy.y, 20, 20]

    #Loop through each brick to see if the ball is colliding with it
    args.state.bricks.each do |b|
      if b.rect.intersect_rect?(ball_rect)
        #Run the linear collider for the brick if there is a collision
        b[:collider_bottom].update args
        b[:collider_right].update args
        b[:collider_left].update args
        b[:collider_top].update args

        b.broken = true
      end
    end

    args.state.bricks = args.state.bricks.reject(&:broken)
  end

  def win_game args
    if args.state.bricks.count == 0 && args.state.game_over_at.elapsed_time > 60
      #Freeze the ball
      args.state.ball.velocity.x = 0
      args.state.ball.velocity.y = 0
      #Freeze the paddle
      args.state.paddle.enabled = false

      args.state.game_over_at = Kernel.tick_count
    end

    if args.state.game_over_at.elapsed_time < 60 && Kernel.tick_count > 60 && args.state.bricks.count == 0
      #Display a "Game over" message
      args.outputs.labels << [100, 100, "CONGRATULATIONS!", 10]
    end
  end

end

def tick args
  defaults args
  render args
  calc args

  #args.outputs.lines << [0, 0, args.grid.w, args.grid.h]

  #$tc+=1
  #if $tc == 5
    #$train << [args.state.ball.xy.x, args.state.ball.xy.y]
    #$tc = 0
  #end
  #for t in $train

    #args.outputs.solids << [t[0],t[1],5,5,255,0,0];
  #end
end

Collision With Object Removal - paddle.rb link

# ./samples/04_physics_and_collisions/10_collision_with_object_removal/app/paddle.rb
class Paddle
  attr_accessor :enabled

  def initialize ()
    @x=WIDTH/2
    @y=100
    @width=100
    @height=20
    @speed=10

    @xyCollision  = LinearCollider.new({x: @x,y: @y+@height+5}, {x: @x+@width, y: @y+@height+5})
    @xyCollision2 = LinearCollider.new({x: @x,y: @y}, {x: @x+@width, y: @y}, :pos)
    @xyCollision3 = LinearCollider.new({x: @x,y: @y}, {x: @x, y: @y+@height+5})
    @xyCollision4 = LinearCollider.new({x: @x+@width,y: @y}, {x: @x+@width, y: @y+@height+5}, :pos)

    @enabled = true
  end

  def update args
    @xyCollision.resetPoints({x: @x,y: @y+@height+5}, {x: @x+@width, y: @y+@height+5})
    @xyCollision2.resetPoints({x: @x,y: @y}, {x: @x+@width, y: @y})
    @xyCollision3.resetPoints({x: @x,y: @y}, {x: @x, y: @y+@height+5})
    @xyCollision4.resetPoints({x: @x+@width,y: @y}, {x: @x+@width, y: @y+@height+5})

    @xyCollision.update  args
    @xyCollision2.update args
    @xyCollision3.update args
    @xyCollision4.update args

    args.inputs.keyboard.key_held.left  ||= false
    args.inputs.keyboard.key_held.right  ||= false

    if not (args.inputs.keyboard.key_held.left == args.inputs.keyboard.key_held.right)
      if args.inputs.keyboard.key_held.left && @enabled
        @x-=@speed
      elsif args.inputs.keyboard.key_held.right && @enabled
        @x+=@speed
      end
    end

    xmin =WIDTH/4
    xmax = 3*(WIDTH/4)
    @x = (@x+@width > xmax) ? xmax-@width : (@x<xmin) ? xmin : @x;
  end

  def render args
    args.outputs.solids << [@x,@y,@width,@height,255,0,0];
  end

  def rect
    [@x, @y, @width, @height]
  end
end

Collision With Object Removal - tests.rb link

# ./samples/04_physics_and_collisions/10_collision_with_object_removal/app/tests.rb
# For advanced users:
# You can put some quick verification tests here, any method
# that starts with the `test_` will be run when you save this file.

# Here is an example test and game

# To run the test: ./dragonruby mygame --eval app/tests.rb --no-tick

class MySuperHappyFunGame
  attr_gtk

  def tick
    outputs.solids << [100, 100, 300, 300]
  end
end

def test_universe args, assert
  game = MySuperHappyFunGame.new
  game.args = args
  game.tick
  assert.true!  args.outputs.solids.length == 1, "failure: a solid was not added after tick"
  assert.false! 1 == 2, "failure: some how, 1 equals 2, the world is ending"
  puts "test_universe completed successfully"
end

puts "running tests"
$gtk.reset 100
$gtk.log_level = :off
$gtk.tests.start

Collision With Object Removal - vector2d.rb link

# ./samples/04_physics_and_collisions/10_collision_with_object_removal/app/vector2d.rb

class Vector2d
  attr_accessor :x, :y

  def initialize x=0, y=0
    @x=x
    @y=y
  end

  #returns a vector multiplied by scalar x
  #x [float] scalar
  def mult x
    r = Vector2d.new(0,0)
    r.x=@x*x
    r.y=@y*x
    r
  end

  # vect [Vector2d] vector to copy
  def copy vect
    Vector2d.new(@x, @y)
  end

  #returns a new vector equivalent to this+vect
  #vect [Vector2d] vector to add to self
  def add vect
    Vector2d.new(@x+vect.x,@y+vect.y)
  end

  #returns a new vector equivalent to this-vect
  #vect [Vector2d] vector to subtract to self
  def sub vect
    Vector2d.new(@x-vect.c, @y-vect.y)
  end

  #return the magnitude of the vector
  def mag
    ((@x**2)+(@y**2))**0.5
  end

  #returns a new normalize version of the vector
  def normalize
    Vector2d.new(@x/mag, @y/mag)
  end

  #TODO delet?
  def distABS vect
    (((vect.x-@x)**2+(vect.y-@y)**2)**0.5).abs()
  end
end

Bouncing Ball With Gravity - main.rb link

# ./samples/04_physics_and_collisions/11_bouncing_ball_with_gravity/app/main.rb
class Game
  attr_gtk

  def tick
    outputs.labels << { x: 30, y: 30.from_top,
                        text: "left/right arrow keys to spin, up arrow to jump, ctrl+r to reset, click two points to place terrain" }
    defaults
    calc
    render
  end

  def defaults
    state.terrain ||= []

    state.player ||= { x: 100,
                       y: 640,
                       dx: 0,
                       dy: 0,
                       radius: 12,
                       drag: 0.05477,
                       gravity: 0.03,
                       entropy: 0.9,
                       angle: 0,
                       facing: 1,
                       angle_velocity: 0,
                       elasticity: 0.5 }

    state.grid_points ||= (1280.idiv(40) + 1).flat_map do |x|
      (720.idiv(40) + 1).map do |y|
        { x: x * 40,
          y: y * 40,
          w: 40,
          h: 40,
          anchor_x: 0.5,
          anchor_y: 0.5 }
      end
    end
  end

  def calc
    player.y = 720  if player.y < 0
    player.x = 1280 if player.x < 0
    player.x = 0    if player.x > 1280
    player.angle_velocity = player.angle_velocity.clamp(-30, 30)
    calc_edit_mode
    calc_play_mode
  end

  def calc_edit_mode
    state.current_grid_point = geometry.find_intersect_rect(inputs.mouse, state.grid_points)
    calc_edit_mode_click
  end

  def calc_edit_mode_click
    return if !state.current_grid_point
    return if !inputs.mouse.click

    if !state.start_point
      state.start_point = state.current_grid_point
    else
      state.terrain << { x: state.start_point.x,
                         y: state.start_point.y,
                         x2: state.current_grid_point.x,
                         y2: state.current_grid_point.y }
      state.start_point = nil
    end
  end

  def calc_play_mode
    player.x += player.dx
    player.dy -= player.gravity
    player.y += player.dy
    player.angle += player.angle_velocity
    player.dy += player.dy * player.drag ** 2 * -1
    player.dx += player.dx * player.drag ** 2 * -1
    player.colliding = false
    player.colliding_with = nil

    if inputs.keyboard.key_down.up
      player.dy += 5 * player.angle.vector_y
      player.dx += 5 * player.angle.vector_x
    end
    player.angle_velocity += inputs.left_right * -1
    player.facing = if inputs.left_right == -1
                      -1
                    elsif inputs.left_right == 1
                      1
                    else
                      player.facing
                    end

    collisions = player_terrain_collisions
    collisions.each do |collision|
      collide! player, collision
    end

    if player.colliding_with
      roll! player, player.colliding_with
    end
  end

  def reflect_velocity! circle, line
    slope = geometry.line_slope line, replace_infinity: 1000
    slope_angle = geometry.line_angle line
    if slope_angle == 90 || slope_angle == 270
      circle.dx *= -circle.elasticity
    else
      circle.angle_velocity += slope * (circle.dx.abs + circle.dy.abs)
      vec = line.x2 - line.x, line.y2 - line.y
      len = Math.sqrt(vec.x**2 + vec.y**2)

      vec.x /= len
      vec.y /= len

      n = geometry.vec2_normal vec

      v_dot_n = geometry.vec2_dot_product({ x: circle.dx, y: circle.dy }, n)

      circle.dx = circle.dx - n.x * (2 * v_dot_n)
      circle.dy = circle.dy - n.y * (2 * v_dot_n)
      circle.dx *= circle.elasticity
      circle.dy *= circle.elasticity
      half_terminal_velocity = 10
      impact_intensity = (circle.dy.abs) / half_terminal_velocity
      impact_intensity = 1 if impact_intensity > 1

      final = (0.9 - 0.8 * impact_intensity)
      next_angular_velocity = circle.angle_velocity * final
      circle.angle_velocity *= final

      if (circle.dx.abs + circle.dy.abs) <= 0.2
        circle.dx = 0
        circle.dy = 0
        circle.angle_velocity *= 0.99
      end

      if circle.angle_velocity.abs <= 0.1
        circle.angle_velocity = 0
      end
    end
  end

  def position_on_line! circle, line
    circle.colliding = true
    point = geometry.line_normal line, circle
    if point.y > circle.y
      circle.colliding_from_above = true
    else
      circle.colliding_from_above = false
    end

    circle.colliding_with = line

    if !geometry.point_on_line? point, line
      distance_from_start_of_line = geometry.distance_squared({ x: line.x, y: line.y }, point)
      distance_from_end_of_line = geometry.distance_squared({ x: line.x2, y: line.y2 }, point)
      if distance_from_start_of_line < distance_from_end_of_line
        point = { x: line.x, y: line.y }
      else
        point = { x: line.x2, y: line.y2 }
      end
    end
    angle = geometry.angle_to point, circle
    circle.y = point.y + angle.vector_y * (circle.radius)
    circle.x = point.x + angle.vector_x * (circle.radius)
  end

  def collide! circle, line
    return if !line
    position_on_line! circle, line
    reflect_velocity! circle, line
    next_player = { x: player.x + player.dx,
                    y: player.y + player.dy,
                    radius: player.radius }
  end

  def roll! circle, line
    slope_angle = geometry.line_angle line
    return if slope_angle == 90 || slope_angle == 270

    ax = -circle.gravity * slope_angle.vector_y
    ay = -circle.gravity * slope_angle.vector_x

    if ax.abs < 0.05 && ay.abs < 0.05
      ax = 0
      ay = 0
    end

    friction_coefficient = 0.0001
    friction_force = friction_coefficient * circle.gravity * slope_angle.vector_x

    circle.dy += ay
    circle.dx += ax

    if circle.colliding_from_above
      circle.dx += circle.angle_velocity * slope_angle.vector_x * 0.1
      circle.dy += circle.angle_velocity * slope_angle.vector_y * 0.1
    else
      circle.dx += circle.angle_velocity * slope_angle.vector_x * -0.1
      circle.dy += circle.angle_velocity * slope_angle.vector_y * -0.1
    end

    if circle.dx != 0
      circle.dx -= friction_force * (circle.dx / circle.dx.abs)
    end

    if circle.dy != 0
      circle.dy -= friction_force * (circle.dy / circle.dy.abs)
    end
  end

  def player_terrain_collisions
    terrain.find_all do |terrain|
             geometry.circle_intersect_line? player, terrain
           end
           .sort_by do |terrain|
             if player.facing == -1
               -terrain.x
             else
               terrain.x
             end
           end
  end

  def render
    render_current_grid_point
    render_preview_line
    render_grid_points
    render_terrain
    render_player
    render_player_terrain_collisions
  end

  def render_player_terrain_collisions
    collisions = player_terrain_collisions
    outputs.lines << collisions.map do |collision|
                       { x: collision.x,
                         y: collision.y,
                         x2: collision.x2,
                         y2: collision.y2,
                         r: 255,
                         g: 0,
                         b: 0 }
                     end
  end

  def render_current_grid_point
    return if state.game_mode == :play
    return if !state.current_grid_point
    outputs.sprites << state.current_grid_point
                            .merge(w: 8,
                                   h: 8,
                                   anchor_x: 0.5,
                                   anchor_y: 0.5,
                                   path: :solid,
                                   g: 0,
                                   r: 0,
                                   b: 0,
                                   a: 128)
  end

  def render_preview_line
    return if state.game_mode == :play
    return if !state.start_point
    return if !state.current_grid_point

    outputs.lines << { x: state.start_point.x,
                       y: state.start_point.y,
                       x2: state.current_grid_point.x,
                       y2: state.current_grid_point.y }
  end

  def render_grid_points
    outputs
      .sprites << state
                    .grid_points
                    .map do |point|
      point.merge w: 8,
                  h: 8,
                  anchor_x: 0.5,
                  anchor_y: 0.5,
                  path: :solid,
                  g: 255,
                  r: 255,
                  b: 255,
                  a: 128
    end
  end

  def render_terrain
    outputs.lines << state.terrain
  end

  def render_player
    outputs.sprites << player_prefab
  end

  def player_prefab
    flip_horizontally = player.facing == -1
    { x: player.x,
      y: player.y,
      w: player.radius * 2,
      h: player.radius * 2,
      angle: player.angle,
      anchor_x: 0.5,
      anchor_y: 0.5,
      path: "sprites/circle/blue.png" }
  end

  def player
    state.player
  end

  def terrain
    state.terrain
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

def reset args
  $terrain = args.state.terrain
  $game = nil
end

Ramp Collision - main.rb link

# ./samples/04_physics_and_collisions/12_ramp_collision/app/main.rb
# sample app shows how to do ramp collision
# based off of the writeup here:
# http://higherorderfun.com/blog/2012/05/20/the-guide-to-implementing-2d-platformers/

# NOTE: at the bottom of the file you'll find $gtk.reset_and_replay "replay.txt"
#       whenever you make changes to this file, a replay will automatically run so you can
#       see how your changes affected the game. Comment out the line at the bottom if you
#       don't want the replay to autmatically run.
def tick args
  tick_toolbar args
  tick_game args
end

def tick_game args
  game_defaults args
  game_input args
  game_calc args
  game_render args
end

def game_input args
  # if space is pressed or held (signifying a jump)
  if args.inputs.keyboard.space
    # change the player's dy to the jump power if the
    # player is not currently touching a ceiling
    if !args.state.player.on_ceiling
      args.state.player.dy = args.state.player.jump_power
      args.state.player.on_floor = false
      args.state.player.jumping = true
    end
  else
    # if the space key is released, then jumping is false
    # and the player will no longer be on the ceiling
    args.state.player.jumping = false
    args.state.player.on_ceiling = false
  end

  # set the player's dx value to the left/right input
  # NOTE: that the speed of the player's dx movement has
  #       a sensitive relation ship with collision detection.
  #       If you increase the speed of the player, you may
  #       need to tweak the collision code to compensate for
  #       the extra horizontal speed.
  args.state.player.dx = args.inputs.left_right * 2
end

def game_render args
  # for each terrain entry, render the line that represents the connection
  # from the tile's left_height to the tile's right_height
  args.outputs.primitives << args.state.terrain.map { |t| t.line }

  # determine if the player sprite needs to be flipped hoizontally
  flip_horizontally = args.state.player.facing == -1

  # render the player
  args.outputs.sprites << args.state.player.merge(flip_horizontally: flip_horizontally)

  args.outputs.labels << {
    x: 640,
    y: 100,
    alignment_enum: 1,
    text: "Left and Right to move player. Space to jump. Use the toolbar at the top to add more terrain."
  }

  args.outputs.labels << {
    x: 640,
    y: 60,
    alignment_enum: 1,
    text: "Click any existing terrain on the map to delete it."
  }
end

def game_calc args
  # set the direction the player is facing based on the
  # the dx value of the player
  if args.state.player.dx > 0
    args.state.player.facing = 1
  elsif args.state.player.dx < 0
    args.state.player.facing = -1
  end

  # preform the calcuation of ramp collision
  calc_collision args

  # reset the player if the go off screen
  calc_off_screen args
end

def game_defaults args
  # how much gravity is in the game
  args.state.gravity ||= 0.1

  # initialized the player to the center of the screen
  args.state.player ||= {
    x: 640,
    y: 360,
    w: 16,
    h: 16,
    dx: 0,
    dy: 0,
    jump_power: 3,
    path: 'sprites/square/blue.png',
    on_floor: false,
    on_ceiling: false,
    facing: 1
  }
end

def calc_collision args
  # increment the players x position by the dx value
  args.state.player.x += args.state.player.dx

  # if the player is not on the floor
  if !args.state.player.on_floor
    # then apply gravity
    args.state.player.dy -= args.state.gravity
    # clamp the max dy value to -12 to 12
    args.state.player.dy = args.state.player.dy.clamp(-12, 12)

    # update the player's y position by the dy value
    args.state.player.y += args.state.player.dy
  end

  # get all colisions between the player and the terrain
  collisions = args.state.geometry.find_all_intersect_rect args.state.player, args.state.terrain

  # if there are no collisions, then the player is not on the floor or ceiling
  # return from the method since there is nothing more to process
  if collisions.length == 0
    args.state.player.on_floor = false
    args.state.player.on_ceiling = false
    return
  end

  # set a local variable to the player since
  # we'll be accessing it a lot
  player = args.state.player

  # sort the collisions by the distance from the collision's center to the player's center
  sorted_collisions = collisions.sort_by do |collision|
    player_center = player.x + player.w / 2
    collision_center = collision.x + collision.w / 2
    (player_center - collision_center).abs
  end

  # define a one pixel wide rectangle that represents the center of the player
  # we'll use this value to determine the location of the player's feet on
  # a ramp
  player_center_rect = {
    x: player.x + player.w / 2 - 0.5,
    y: player.y,
    w: 1,
    h: player.h
  }

  # for each collision...
  sorted_collisions.each do |collision|
    # if the player doesn't intersect with the collision,
    # then set the player's on_floor and on_ceiling values to false
    # and continue to the next collision
    if !collision.intersect_rect? player_center_rect
      player.on_floor = false
      player.on_ceiling = false
      next
    end

    if player.dy < 0
      # if the player is falling
      # the percentage of the player's center relative to the collision
      # is a difference from the collision to the player (as opposed to the player to the collision)
      perc = (collision.x - player_center_rect.x) / player.w
      height_of_slope = collision.tile.left_height - collision.tile.right_height

      new_y = (collision.y + collision.tile.left_height + height_of_slope * perc)
      diff = new_y - player.y

      if diff < 0
        # if the current fall rate of the player is less than the difference
        # of the player's new y position and the player's current y position
        # then don't set the player's y position to the new y position
        # and wait for another application of gravity to bring the player a little
        # closer
        if player.dy.abs >= diff.abs
          # if the player's current fall speed can cover the distance to the
          # new y position, then set the player's y position to the new y position
          # and mark them as being on the floor so that gravity no longer get's processed
          player.y = new_y
          player.on_floor = true

          # given the player's speed, set the player's dy to a value that will
          # keep them from bouncing off the floor when the ramp is steep
          # NOTE: if you change the player's speed, then this value will need to be adjusted
          #       to keep the player from bouncing off the floor
          player.dy = -1
        end
      elsif diff > 0 && diff < 8
        # there's a small edge case where collision may be processed from
        # below the terrain (eg when the player is jumping up and hitting the
        # ramp from below). The moment when jump is released, the player's dy
        # value could result in the player tunneling through the terrain,
        # and get popped on to the top side.

        # testing to make sure the distance that will be displaced is less than
        # 8 pixels will keep this tunneling from happening
        player.y = new_y
        player.on_floor = true

        # given the player's speed, set the player's dy to a value that will
        # keep them from bouncing off the floor when the ramp is steep
        # NOTE: if you change the player's speed, then this value will need to be adjusted
        #       to keep the player from bouncing off the floor
        player.dy = -1
      end
    elsif player.dy > 0
      # if the player is jumping
      # the percentage of the player's center relative to the collision
      # is a difference is reversed from the player to the collision (as opposed to the player to the collision)
      perc = (player_center_rect.x - collision.x) / player.w

      # the height of the slope is also reversed when approaching the collision from the bottom
      height_of_slope = collision.tile.right_height - collision.tile.left_height

      new_y = collision.y + collision.tile.left_height + height_of_slope * perc

      # since this collision is being processed from below, the difference
      # between the current players position and the new y position is
      # based off of the player's top position (their head)
      player_top = player.y + player.h

      diff = new_y - player_top

      # we also need to calculate the difference between the player's bottom
      # and the new position. This will be used to determine if the player
      # can jump from the new_y position
      diff_bottom = new_y - player.y


      # if the player's current rising speed can cover the distance to the
      # new y position, then set the player's y position to the new y position
      # an mark them as being on the floor so that gravity no longer get's processed
      can_cover_distance_to_new_y = player.dy >= diff.abs && player.dy.sign == diff.sign

      # another scenario that needs to be covered is if the player's top is already passed
      # the new_y position (their rising speed made them partially clip through the collision)
      player_top_above_new_y = player_top > new_y

      # if either of the conditions above is true then we want to set the player's y position
      if can_cover_distance_to_new_y || player_top_above_new_y
        # only set the player's y position to the new y position if the player's
        # cannot escape the collision by jumping up from the new_y position
        if diff_bottom >= player.jump_power
          player.y = new_y.floor - player.h

          # after setting the new_y position, we need to determine if the player
          # if the player is touching the ceiling or not
          # touching the ceiling disables the ability for the player to jump/increase
          # their dy value any more than it already is
          if player.jumping
            # disable jumping if the player is currently moving upwards
            player.on_ceiling = true

            # NOTE: if you change the player's speed, then this value will need to be adjusted
            #       to keep the player from bouncing off the ceiling as they move right and left
            player.dy = 1
          else
            # if the player is not currently jumping, then set their dy to 0
            # so they can immediately start falling after the collision
            # this also means that they are no longer on the ceiling and can jump again
            player.dy = 0
            player.on_ceiling = false
          end
        end
      end
    end
  end
end

def calc_off_screen args
  below_screen = args.state.player.y + args.state.player.h < 0
  above_screen = args.state.player.y > 720 + args.state.player.h
  off_screen_left = args.state.player.x + args.state.player.w < 0
  off_screen_right = args.state.player.x > 1280

  # if the player is off the screen, then reset them to the top of the screen
  if below_screen || above_screen || off_screen_left || off_screen_right
    args.state.player.x = 640
    args.state.player.y = 720
    args.state.player.dy = 0
    args.state.player.on_floor = false
  end
end

def tick_toolbar args
  # ================================================
  # tollbar defaults
  # ================================================
  if !args.state.toolbar
    # these are the tiles you can select from
    tile_definitions = [
      { name: "16-12", left_height: 16, right_height: 12  },
      { name: "12-8",  left_height: 12, right_height: 8   },
      { name: "8-4",   left_height: 8,  right_height: 4   },
      { name: "4-0",   left_height: 4,  right_height: 0   },
      { name: "0-4",   left_height: 0,  right_height: 4   },
      { name: "4-8",   left_height: 4,  right_height: 8   },
      { name: "8-12",  left_height: 8,  right_height: 12  },
      { name: "12-16", left_height: 12, right_height: 16  },

      { name: "16-8",  left_height: 16, right_height: 8   },
      { name: "8-0",   left_height: 8,  right_height: 0   },
      { name: "0-8",   left_height: 0,  right_height: 8   },
      { name: "8-16",  left_height: 8,  right_height: 16  },

      { name: "0-0",   left_height: 0,  right_height: 0   },
      { name: "8-8",   left_height: 8,  right_height: 8   },
      { name: "16-16", left_height: 16, right_height: 16  },
    ]

    # toolbar data representation which will be used to render the toolbar.
    # the buttons array will be used to render the buttons
    # the toolbar_rect will be used to restrict the creation of tiles
    # within the toolbar area
    args.state.toolbar = {
      toolbar_rect: nil,
      buttons: []
    }

    # for each tile definition, create a button
    args.state.toolbar.buttons = tile_definitions.map_with_index do |spec, index|
      left_height  = spec.left_height
      right_height = spec.right_height
      button_size  = 48
      column_size  = 15
      column_padding = 2
      column = index % column_size
      column_padding = column * column_padding
      margin = 10
      row = index.idiv(column_size)
      row_padding = row * 2
      x = margin + column_padding + (column * button_size)
      y = (margin + button_size + row_padding + (row * button_size)).from_top

      # when a tile is added, the data of this button will be used
      # to construct the terrain

      # each tile has an x, y, w, h which represents the bounding box
      # of the button.
      # the button also contains the left_height and right_height which is
      # important when determining collision of the ramps
      {
        name: spec.name,
        left_height: left_height,
        right_height: right_height,
        button_rect: {
          x: x,
          y: y,
          w: 48,
          h: 48
        }
      }
    end

    # with the buttons populated, compute the bounding box of the entire
    # toolbar (again this will be used to restrict the creation of tiles)
    min_x = args.state.toolbar.buttons.map { |t| t.button_rect.x }.min
    min_y = args.state.toolbar.buttons.map { |t| t.button_rect.y }.min

    max_x = args.state.toolbar.buttons.map { |t| t.button_rect.x }.max
    max_y = args.state.toolbar.buttons.map { |t| t.button_rect.y }.max

    args.state.toolbar.rect = {
      x: min_x - 10,
      y: min_y - 10,
      w: max_x - min_x + 10 + 64,
      h: max_y - min_y + 10 + 64
    }
  end

  # set the selected tile to the last button in the toolbar
  args.state.selected_tile ||= args.state.toolbar.buttons.last

  # ================================================
  # starting terrain generation
  # ================================================
  if !args.state.terrain
    world = [
      { row: 14, col: 25, name: "0-8"   },
      { row: 14, col: 26, name: "8-16"  },
      { row: 15, col: 27, name: "0-8"   },
      { row: 15, col: 28, name: "8-16"  },
      { row: 16, col: 29, name: "0-8"   },
      { row: 16, col: 30, name: "8-16"  },
      { row: 17, col: 31, name: "0-8"   },
      { row: 17, col: 32, name: "8-16"  },
      { row: 18, col: 33, name: "0-8"   },
      { row: 18, col: 34, name: "8-16"  },
      { row: 18, col: 35, name: "16-12" },
      { row: 18, col: 36, name: "12-8"  },
      { row: 18, col: 37, name: "8-4"   },
      { row: 18, col: 38, name: "4-0"   },
      { row: 18, col: 39, name: "0-0"   },
      { row: 18, col: 40, name: "0-0"   },
      { row: 18, col: 41, name: "0-0"   },
      { row: 18, col: 42, name: "0-4"   },
      { row: 18, col: 43, name: "4-8"   },
      { row: 18, col: 44, name: "8-12"  },
      { row: 18, col: 45, name: "12-16" },
    ]

    args.state.terrain = world.map do |tile|
      template = tile_by_name(args, tile.name)
      next if !template
      grid_rect = grid_rect_for(tile.row, tile.col)
      new_terrain_definition(grid_rect, template)
    end
  end

  # ================================================
  # toolbar input and rendering
  # ================================================
  # store the mouse position alligned to the tile grid
  mouse_grid_aligned_rect = grid_aligned_rect args.inputs.mouse, 16

  # determine if the mouse intersects the toolbar
  mouse_intersects_toolbar = args.state.toolbar.rect.intersect_rect? args.inputs.mouse

  # determine if the mouse intersects a toolbar button
  toolbar_button = args.state.toolbar.buttons.find { |t| t.button_rect.intersect_rect? args.inputs.mouse }

  # determine if the mouse click occurred over a tile in the terrain
  terrain_tile = args.geometry.find_intersect_rect mouse_grid_aligned_rect, args.state.terrain


  # if a mouse click occurs....
  if args.inputs.mouse.click
    if toolbar_button
      # if a toolbar button was clicked, set the currently selected tile to the toolbar tile
      args.state.selected_tile = toolbar_button
    elsif terrain_tile
      # if a tile was clicked, delete it from the terrain
      args.state.terrain.delete terrain_tile
    elsif !args.state.toolbar.rect.intersect_rect? args.inputs.mouse
      # if the mouse was not clicked in the toolbar area
      # add a new terrain based off of the information in the selected tile
      args.state.terrain << new_terrain_definition(mouse_grid_aligned_rect, args.state.selected_tile)
    end
  end

  # render a light blue background for the toolbar button that is currently
  # being hovered over (if any)
  if toolbar_button
    args.outputs.primitives << toolbar_button.button_rect.merge(primitive_marker: :solid, a: 64, b: 255)
  end

  # put a blue background around the currently selected tile
  args.outputs.primitives << args.state.selected_tile.button_rect.merge(primitive_marker: :solid, b: 255, r: 128, a: 64)

  if !mouse_intersects_toolbar
    if terrain_tile
      # if the mouse is hoving over an existing terrain tile, render a red border around the
      # tile to signify that it will be deleted if the mouse is clicked
      args.outputs.borders << terrain_tile.merge(a: 255, r: 255)
    else
      # if the mouse is not hovering over an existing terrain tile, render the currently
      # selected tile at the mouse position
      grid_aligned_rect = grid_aligned_rect args.inputs.mouse, 16

      args.outputs.solids << {
        **grid_aligned_rect,
        a: 30,
        g: 128
      }

      args.outputs.lines << {
        x:  grid_aligned_rect.x,
        y:  grid_aligned_rect.y + args.state.selected_tile.left_height,
        x2: grid_aligned_rect.x + grid_aligned_rect.w,
        y2: grid_aligned_rect.y + args.state.selected_tile.right_height,
      }
    end
  end

  # render each toolbar button using two primitives, a border to denote
  # the click area of the button, and a line to denote the terrain that
  # will be created when the button is clicked
  args.outputs.primitives << args.state.toolbar.buttons.map do |toolbar_tile|
    primitives = []
    scale = toolbar_tile.button_rect.w / 16

    primitive_type = :border

    [
      {
        **toolbar_tile.button_rect,
        primitive_marker: primitive_type,
        a: 64,
        g: 128
      },
      {
        x:  toolbar_tile.button_rect.x,
        y:  toolbar_tile.button_rect.y + toolbar_tile.left_height * scale,
        x2: toolbar_tile.button_rect.x + toolbar_tile.button_rect.w,
        y2: toolbar_tile.button_rect.y + toolbar_tile.right_height * scale
      }
    ]
  end
end

# ================================================
# helper methods
#=================================================

# converts a row and column on the grid to
# a rect
def grid_rect_for row, col
  { x: col * 16, y: row * 16, w: 16, h: 16 }
end

# find a tile by name
def tile_by_name args, name
  args.state.toolbar.buttons.find { |b| b.name == name }
end

# data structure containing terrain information
# specifcially tile.left_height and tile.right_height
def new_terrain_definition grid_rect, tile
  grid_rect.merge(
    tile: tile,
    line: {
      x:  grid_rect.x,
      y:  grid_rect.y + tile.left_height,
      x2: grid_rect.x + grid_rect.w,
      y2: grid_rect.y + tile.right_height
    }
  )
end

# helper method that returns a grid aligned rect given
# an arbitrary rect and a grid size
def grid_aligned_rect point, size
  grid_aligned_x = point.x - (point.x % size)
  grid_aligned_y = point.y - (point.y % size)
  { x: grid_aligned_x.to_i, y: grid_aligned_y.to_i, w: size.to_i, h: size.to_i }
end

$gtk.reset_and_replay "replay.txt", speed: 2

Verlet Integration - main.rb link

# ./samples/04_physics_and_collisions/13_verlet_integration/app/main.rb
# https://www.youtube.com/watch?v=D2M8jTtKi44

class Game
  attr_gtk

  def initialize
  end

  def defaults
    state.objects ||= []
  end

  def render
    outputs.watch "#{GTK.current_framerate} FPS"
    outputs.watch "#{state.objects.length}"
    outputs.primitives << state.objects
  end

  def calc_dt dt
    state.objects.each do |object|
      object.prev_x ||= object.x
      object.prev_y ||= object.y
      if !object.acceleration_x
        object.acceleration_x = object.start_acceleration_x
      else
        object.acceleration_x = 0
      end

      if !object.acceleration_y
        object.acceleration_y = object.start_acceleration_y
      else
        object.acceleration_y = -0.25 * dt
      end

      if object.y < 0
        object.y = 0
      end

      if object.x < 0
        object.x = 0
      elsif (object.x + object.w) > 1280
        object.x = 1280 - object.w
      end

      dx = object.x - object.prev_x
      dy = object.y - object.prev_y
      dx += object.acceleration_x * dt
      dy += object.acceleration_y * dt
      dx *= object.drag_x ** dt
      dy *= object.drag_y ** dt

      object.prev_x = object.x
      object.prev_y = object.y
      object.x += dx
      object.y += dy
    end

    Geometry.each_intersect_rect(state.objects, state.objects) do |o_1, o_2|
      o_1_center_x = o_1.x + o_1.radius
      o_1_center_y = o_1.y + o_1.radius
      o_2_center_x = o_2.x + o_2.radius
      o_2_center_y = o_2.y + o_2.radius

      distance_x = o_1_center_x - o_2_center_x
      distance_y = o_1_center_y - o_2_center_y
      distance = Math.sqrt(distance_x * distance_x + distance_y * distance_y)

      if distance < o_1.radius + o_2.radius
        v_x = (o_2_center_x - o_1_center_x) / distance
        v_y = (o_2_center_y - o_1_center_y) / distance
        delta = o_1.radius + o_2.radius - distance

        o_1_dx = -0.75 * dt * delta * v_x * 0.5
        o_1_dy = -0.75 * dt * delta * v_y * 0.5
        o_1.x += o_1_dx
        o_1.y += o_1_dy

        o_2_dx = 0.75 * dt * delta * v_x * 0.5
        o_2_dy = 0.75 * dt * delta * v_y * 0.5
        o_2.x += o_2_dx
        o_2.y += o_2_dy
      end
    end
  end

  def calc
    if inputs.mouse.held || state.objects.length < 100
      angle = rand(360)
      acc_x = angle.vector_x * 20
      acc_y = angle.vector_y * 20
      mouse_x = if inputs.mouse.click || inputs.mouse.held
                  inputs.mouse.x
                else
                  640
                end

      mouse_y = if inputs.mouse.click || inputs.mouse.held
                  inputs.mouse.y
                else
                  540
                end

      color = [:red, :blue].sample

      state.objects << {
        x: mouse_x - 8,
        y: mouse_y - 8,
        w: 16,
        h: 16,
        radius: 8,
        path: "sprites/square/#{color}.png",
        start_acceleration_x: acc_x,
        start_acceleration_y: acc_y,
        acceleration_x: nil,
        acceleration_y: nil,
        drag_x: 0.95,
        drag_y: 0.99
      }
    end

    calc_dt 0.5
    calc_dt 0.5
  end

  def tick
    defaults
    calc
    render
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

def sub_tick args
end

def reset args
  $game = nil
end

GTK.reset

Mouse link

Mouse Click - main.rb link

# ./samples/05_mouse/01_mouse_click/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - product: Returns an array of all combinations of elements from all arrays.

   For example, [1,2].product([1,2]) would return the following array...
   [[1,1], [1,2], [2,1], [2,2]]
   More than two arrays can be given to product and it will still work,
   such as [1,2].product([1,2],[3,4]). What would product return in this case?

   Answer:
   [[1,1,3],[1,1,4],[1,2,3],[1,2,4],[2,1,3],[2,1,4],[2,2,3],[2,2,4]]

 - num1.fdiv(num2): Returns the float division (will have a decimal) of the two given numbers.
   For example, 5.fdiv(2) = 2.5 and 5.fdiv(5) = 1.0

 - yield: Allows you to call a method with a code block and yield to that block.

 Reminders:

 - Hash#inside_rect?: Returns true or false depending on if the point is inside the rect.

 - String interpolation: Uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

 - args.inputs.mouse.click: This property will be set if the mouse was clicked.

 - Ternary operator (?): Will evaluate a statement (just like an if statement)
   and perform an action if the result is true or another action if it is false.

 - reject: Removes elements from a collection if they meet certain requirements.

 - args.outputs.borders: An array. The values generate a border.
   The parameters are [X, Y, WIDTH, HEIGHT, RED, GREEN, BLUE]
   For more information about borders, go to mygame/documentation/03-solids-and-borders.md.

 - args.outputs.labels: An array. The values generate a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGNMENT, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.

=end

# This sample app is a classic game of Tic Tac Toe.
class TicTacToe
  attr_gtk # class macro that adds outputs, inputs, state, etc to class

  def tick
    init_new_game
    render_board
    input_board
  end

  def init_new_game
    state.current_turn       ||= :x
    state.space_combinations ||= [-1, 0, 1].product([-1, 0, 1]).to_a
    if !state.spaces
      state.square_size ||= 80
      state.board_left  ||= grid.w_half - state.square_size * 1.5
      state.board_top   ||= grid.h_half - state.square_size * 1.5
      state.spaces = {}
      state.space_combinations.each do |x, y|
        state.spaces[x]    ||= {}
        state.spaces[x][y] ||= {}
        state.spaces[x][y].hitbox ||= {
          x: state.board_left + (x + 1) * state.square_size,
          y: state.board_top  + (y + 1) * state.square_size,
          w: state.square_size,
          h: state.square_size
        }
      end
    end
  end

  # Uses borders to create grid squares for the game's board. Also outputs the game pieces using labels.
  def render_board
    # At first glance, the add(1) looks pretty trivial. But if you remove it,
    # you'll see that the positioning of the board would be skewed without it!
    # Or if you put 2 in the parenthesis, the pieces will be placed in the wrong squares
    # due to the change in board placement.
    outputs.borders << all_spaces.map do |space| # outputs borders for all board spaces
                         space.hitbox
                       end

    hovered_box = all_spaces.find do |space|
      inputs.mouse.inside_rect?(space.hitbox) && !space.piece
    end

    if hovered_box && !state.game_over
      args.outputs.solids << { x: hovered_box.hitbox.x,
                               y: hovered_box.hitbox.y,
                               w: hovered_box.hitbox.w,
                               h: hovered_box.hitbox.h,
                               r: 0,
                               g: 100,
                               b: 200,
                               a: 80 }
    end

    # put label in each filled space of board
    outputs.labels << filled_spaces.map do |space|
      { x: space.hitbox.x + space.hitbox.w / 2,
        y: space.hitbox.y + space.hitbox.h / 2,
        anchor_x: 0.5,
        anchor_y: 0.5,
        size_px: 40,
        text: space.piece }
    end

    # Uses a label to output whether x or o won, or if a draw occurred.
    # If the game is ongoing, a label shows whose turn it currently is.
    outputs.labels << if state.x_won
                        { x: 640, y: 600, text: "x won", size_px: 40, anchor_x: 0.5, anchor_y: 0.5 }
                      elsif state.o_won
                        { x: 640, y: 600, text: "o won", size_px: 40, anchor_x: 0.5, anchor_y: 0.5 }
                      elsif state.draw
                        { x: 640, y: 600, text: "draw", size_px: 40, anchor_x: 0.5, anchor_y: 0.5 }
                      else
                        { x: 640, y: 600, text: "turn: #{state.current_turn}", size_px: 40, anchor_x: 0.5, anchor_y: 0.5 }
                      end
  end

  # Calls the methods responsible for handling user input and determining the winner.
  # Does nothing unless the mouse is clicked.
  def input_board
    return unless inputs.mouse.click
    input_place_piece
    input_restart_game
    determine_winner
  end

  # Handles user input for placing pieces on the board.
  def input_place_piece
    return if state.game_over

    # Checks to find the space that the mouse was clicked inside of, and makes sure the space does not already
    # have a piece in it.
    space = all_spaces.find do |space|
      inputs.mouse.click.point.inside_rect?(space.hitbox) && !space.piece
    end

    # The piece that goes into the space belongs to the player whose turn it currently is.
    return unless space

    space.piece = state.current_turn

    # This ternary operator statement allows us to change the current player's turn.
    # If it is currently x's turn, it becomes o's turn. If it is not x's turn, it become's x's turn.
    state.current_turn = state.current_turn == :x ? :o : :x
  end

  # Resets the game.
  def input_restart_game
    return unless state.game_over
    gtk.reset
    init_new_game
  end

  # Checks if x or o won the game.
  # If neither player wins and all nine squares are filled, a draw happens.
  # Once a player is chosen as the winner or a draw happens, the game is over.
  def determine_winner
    state.x_won = won? :x # evaluates to either true or false (boolean values)
    state.o_won = won? :o
    state.draw = true if filled_spaces.length == 9 && !state.x_won && !state.o_won
    state.game_over = state.x_won || state.o_won || state.draw
  end

  # Determines if a player won by checking if there is a horizontal match or vertical match.
  # Horizontal_match and vertical_match have boolean values. If either is true, the game has been won.
  def won? piece
    # performs action on all space combinations
    won = [[-1, 0, 1]].product([-1, 0, 1]).map do |xs, y|
      # Checks if the 3 grid spaces with the same y value (or same row) and
      # x values that are next to each other have pieces that belong to the same player.
      # Remember, the value of piece is equal to the current turn (which is the player).
      horizontal_match = state.spaces[xs[0]][y].piece == piece &&
                         state.spaces[xs[1]][y].piece == piece &&
                         state.spaces[xs[2]][y].piece == piece

      # Checks if the 3 grid spaces with the same x value (or same column) and
      # y values that are next to each other have pieces that belong to the same player.
      # The && represents an "and" statement: if even one part of the statement is false,
      # the entire statement evaluates to false.
      vertical_match = state.spaces[y][xs[0]].piece == piece &&
                       state.spaces[y][xs[1]].piece == piece &&
                       state.spaces[y][xs[2]].piece == piece

      horizontal_match || vertical_match # if either is true, true is returned
    end

    # Sees if there is a diagonal match, starting from the bottom left and ending at the top right.
    # Is added to won regardless of whether the statement is true or false.
    won << (state.spaces[-1][-1].piece == piece && # bottom left
            state.spaces[ 0][ 0].piece == piece && # center
            state.spaces[ 1][ 1].piece == piece)   # top right

    # Sees if there is a diagonal match, starting at the bottom right and ending at the top left
    # and is added to won.
    won << (state.spaces[ 1][-1].piece == piece && # bottom right
            state.spaces[ 0][ 0].piece == piece && # center
            state.spaces[-1][ 1].piece == piece)   # top left

    # Any false statements (meaning false diagonal matches) are rejected from won
    won.reject_false.any?
  end

  # Defines filled spaces on the board by rejecting all spaces that do not have game pieces in them.
  # The ! before a statement means "not". For example, we are rejecting any space combinations that do
  # NOT have pieces in them.
  def filled_spaces
    all_spaces.reject { |space| !space.piece } # reject spaces with no pieces in them
  end

  # Defines all spaces on the board.
  def all_spaces
    state.space_combinations.map do |x, y|
      state.spaces[x][y] # yield if a block is given
    end
  end
end

$tic_tac_toe = nil

def tick args
  args.outputs.labels << { x: 640,
                           y: 700,
                           anchor_x: 0.5,
                           anchor_y: 0.5,
                           text: "Sample app shows how to work with mouse clicks and hitboxes." }
  $tic_tac_toe ||= TicTacToe.new
  $tic_tac_toe.args = args
  $tic_tac_toe.tick
end

Mouse Move - main.rb link

# ./samples/05_mouse/02_mouse_move/app/main.rb
=begin

 Reminders:

 - find_all: Finds all elements of a collection that meet certain requirements.
   For example, in this sample app, we're using find_all to find all zombies that have intersected
   or hit the player's sprite since these zombies have been killed.

 - args.inputs.keyboard.key_down.KEY: Determines if a key is being held or pressed.
   Stores the frame the "down" event occurred.
   For more information about the keyboard, go to mygame/documentation/06-keyboard.md.

 - args.outputs.sprites: An array. The values generate a sprite.
   The parameters are [X, Y, WIDTH, HEIGHT, PATH, ANGLE, ALPHA, RED, GREEN, BLUE]
   For more information about sprites, go to mygame/documentation/05-sprites.md.

 - args.state.new_entity: Used when we want to create a new object, like a sprite or button.
   When we want to create a new object, we can declare it as a new entity and then define
   its properties. (Remember, you can use state to define ANY property and it will
   be retained across frames.)

 - String interpolation: Uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

 - map: Ruby method used to transform data; used in arrays, hashes, and collections.
   Can be used to perform an action on every element of a collection, such as multiplying
   each element by 2 or declaring every element as a new entity.

 - sample: Chooses a random element from the array.

 - reject: Removes elements that meet certain requirements.
   In this sample app, we're removing/rejecting zombies that reach the center of the screen. We're also
   rejecting zombies that were killed more than 30 frames ago.

=end

# This sample app allows users to move around the screen in order to kill zombies. Zombies appear from every direction so the goal
# is to kill the zombies as fast as possible!

class ProtectThePuppiesFromTheZombies
  attr_accessor :grid, :inputs, :state, :outputs

  # Calls the methods necessary for the game to run properly.
  def tick
    defaults
    render
    calc
    input
  end

  # Sets default values for the zombies and for the player.
  # Initialization happens only in the first frame.
  def defaults
    state.flash_at               ||= 0
    state.zombie_min_spawn_rate  ||= 60
    state.zombie_spawn_countdown ||= random_spawn_countdown state.zombie_min_spawn_rate
    state.zombies                ||= []
    state.killed_zombies         ||= []

    # Declares player as a new entity and sets its properties.
    # The player begins the game in the center of the screen, not moving in any direction.
    state.player ||= { x: 640,
                       y: 360,
                       w: 4 * 3,
                       h: 8 * 3,
                       attack_angle: 0,
                       dx: 0,
                       dy: 0,
                       created_at: Kernel.tick_count }
  end

  # Outputs a gray background.
  # Calls the methods needed to output the player, zombies, etc onto the screen.
  def render
    outputs.background_color = [100, 100, 100]
    render_zombies
    render_killed_zombies
    render_player
    render_flash
  end

  # Outputs the zombies on the screen and sets values for the sprites, such as the position, width, height, and animation.
  def render_zombies
    outputs.sprites << state.zombies.map do |z| # performs action on all zombies in the collection
      z.merge path: animation_sprite(z)  # sets definition for sprite, calls animation_sprite method
    end
  end

  # Outputs sprites of killed zombies, and displays a slash image to show that a zombie has been killed.
  def render_killed_zombies
    outputs.sprites << state.killed_zombies.map do |z| # performs action on all killed zombies in collection
      zombie = { x: z.x,
                 y: z.y,
                 w: 4 * 3,
                 h: 8 * 3,
                 path: animation_sprite(z, z.death_at), # calls animation_sprite method
                 a: 255 * z.death_at.ease(30, :flip) }  # transparency of a zombie changes when they die

      # Sets values to output the slash over the zombie's sprite when a zombie is killed.
      # The slash is tilted 45 degrees from the angle of the player's attack.
      # Change the 3 inside scale_rect to 30 and the slash will be HUGE! Scale_rect positions
      # the slash over the killed zombie's sprite.
      [zombie,
       zombie.merge(path: 'sprites/slash.png',
                    angle: 45 + (state.player.attack_angle_on_click || 0)).scale_rect(3, 0.5, 0.5)]
    end
  end

  # Outputs the player sprite using the images in the sprites folder.
  def render_player
    # Outputs a small red square that previews the angles that the player can attack in.
    # It can be moved in a perfect circle around the player to show possible movements.
    # Change the 60 in the parenthesis and see what happens to the movement of the red square.
    outputs.sprites << { x: state.player.x + state.player.attack_angle.vector_x(60),
                         y: state.player.y + state.player.attack_angle.vector_y(60),
                         w: 3,
                         h: 3,
                         r: 255,
                         g: 0,
                         b: 0,
                         path: :solid }

    outputs.sprites << { x: state.player.x,
                         y: state.player.y,
                         w: 4 * 3,
                         h: 8 * 3,
                         path: "sprites/player-#{animation_index(state.player.created_at.elapsed_time)}.png" } # string interpolation
  end

  # Renders flash as a solid. The screen turns white for 10 frames when a zombie is killed.
  def render_flash
    return if state.flash_at.elapsed_time > 10 # return if more than 10 frames have passed since flash.
    # Transparency gradually changes (or eases) during the 10 frames of flash.
    outputs.primitives << { **grid.rect, r: 255, g: 255, b: 255, a: 255 * state.flash_at.ease(10, :flip), path: :solid }
  end

  # Calls all methods necessary for performing calculations.
  def calc
    calc_spawn_zombie
    calc_move_zombies
    calc_player
    calc_kill_zombie
  end

  # Decreases the zombie spawn countdown by 1 if it has a value greater than 0.
  def calc_spawn_zombie
    if state.zombie_spawn_countdown > 0
      state.zombie_spawn_countdown -= 1
      return
    end

    # New zombies are created, positioned on the screen, and added to the zombies collection.
    state.zombies << (if rand > 0.5
                       {
                         x: grid.rect.w.randomize(:ratio), # random x position on screen (within grid scope)
                         y: [-10, 730].sample, # y position is set to either -10 or 730 (randomly chosen)
                         w: 4 * 3, h: 8 * 3,
                         created_at: Kernel.tick_count
                       }
                      else
                       {
                         x: [-10, 1290].sample, # x position is set to either -10 or 1290 (randomly chosen)
                         y: grid.rect.w.randomize(:ratio), # random y position on screen
                         w: 4 * 3, h: 8 * 3,
                         created_at: Kernel.tick_count
                       }
                      end)

    # Calls random_spawn_countdown method (determines how fast new zombies appear)
    state.zombie_spawn_countdown = random_spawn_countdown state.zombie_min_spawn_rate
    state.zombie_min_spawn_rate -= 1
    # set to either the current zombie_min_spawn_rate or 0, depending on which value is greater
    state.zombie_min_spawn_rate  = state.zombie_min_spawn_rate.clamp(0)
  end

  # Moves all zombies towards the center of the screen.
  # All zombies that reach the center (640, 360) are rejected from the zombies collection and disappear.
  def calc_move_zombies
    state.zombies.each do |z| # for each zombie in the collection
      z.y = z.y.towards(360, 0.1) # move the zombie towards the center (640, 360) at a rate of 0.1
      z.x = z.x.towards(640, 0.1) # change 0.1 to 1.1 and see how much faster the zombies move to the center
    end
    state.zombies = state.zombies.reject { |z| z.y == 360 && z.x == 640 } # remove zombies that are in center
  end

  # Calculates the position and movement of the player on the screen.
  def calc_player
    state.player.x += state.player.dx # changes x based on dx (change in x)
    state.player.y += state.player.dy # changes y based on dy (change in y)

    state.player.dx *= 0.9 # scales dx down
    state.player.dy *= 0.9 # scales dy down

    # Compares player's x to 1280 to find lesser value, then compares result to 0 to find greater value.
    # This ensures that the player remains within the screen's scope.
    state.player.x = state.player.x.clamp(0, 1280)
    state.player.y = state.player.y.clamp(0, 720) # same with player's y
  end

  # Finds all zombies that intersect with the player's sprite. These zombies are removed from the zombies collection
  # and added to the killed_zombies collection since any zombie that intersects with the player is killed.
  def calc_kill_zombie

    # Find all zombies that intersect with the player. They are considered killed.
    killed_this_frame = state.zombies.find_all { |z| (z.intersect_rect? state.player) }
    state.zombies = state.zombies - killed_this_frame # remove newly killed zombies from zombies collection
    state.killed_zombies += killed_this_frame # add newly killed zombies to killed zombies

    if killed_this_frame.length > 0 # if atleast one zombie was killed in the frame
      state.flash_at = Kernel.tick_count # flash_at set to the frame when the zombie was killed
    # Don't forget, the rendered flash lasts for 10 frames after the zombie is killed (look at render_flash method)
    end

    # Sets the tick_count (passage of time) as the value of the death_at variable for each killed zombie.
    # Death_at stores the frame a zombie was killed.
    killed_this_frame.each do |z|
      z.death_at = Kernel.tick_count
    end

    # Zombies are rejected from the killed_zombies collection depending on when they were killed.
    # They are rejected if more than 30 frames have passed since their death.
    state.killed_zombies = state.killed_zombies.reject { |z| Kernel.tick_count - z.death_at > 30 }
  end

  # Uses input from the user to move the player around the screen.
  def input

    # If the "a" key or left key is pressed, the x position of the player decreases.
    # Otherwise, if the "d" key or right key is pressed, the x position of the player increases.
    if inputs.keyboard.key_held.a || inputs.keyboard.key_held.left
      state.player.x -= 5
    elsif inputs.keyboard.key_held.d || inputs.keyboard.key_held.right
      state.player.x += 5
    end

    # If the "w" or up key is pressed, the y position of the player increases.
    # Otherwise, if the "s" or down key is pressed, the y position of the player decreases.
    if inputs.keyboard.key_held.w || inputs.keyboard.key_held.up
      state.player.y += 5
    elsif inputs.keyboard.key_held.s || inputs.keyboard.key_held.down
      state.player.y -= 5
    end

    # Sets the attack angle so the player can move and attack in the precise direction it wants to go.
    # If the mouse is moved, the attack angle is changed (based on the player's position and mouse position).
    # Attack angle also contributes to the position of red square.
    if inputs.mouse.moved
      state.player.attack_angle = inputs.mouse.position.angle_from [state.player.x, state.player.y]
    end

    if inputs.mouse.click && state.player.dx < 0.5 && state.player.dy < 0.5
      state.player.attack_angle_on_click = inputs.mouse.position.angle_from [state.player.x, state.player.y]
      state.player.attack_angle = state.player.attack_angle_on_click # player's attack angle is set
      state.player.dx = state.player.attack_angle.vector_x(25) # change in player's position
      state.player.dy = state.player.attack_angle.vector_y(25)
    end
  end

  # Sets the zombie spawn's countdown to a random number.
  # How fast zombies appear (change the 60 to 6 and too many zombies will appear at once!)
  def random_spawn_countdown minimum
    10.randomize(:ratio, :sign).to_i + 60
  end

  # Helps to iterate through the images in the sprites folder by setting the animation index.
  # 3 frames is how long to show an image, and 6 is how many images to flip through.
  def animation_index at
    at.idiv(3).mod(6)
  end

  # Animates the zombies by using the animation index to go through the images in the sprites folder.
  def animation_sprite zombie, at = nil
    at ||= zombie.created_at.elapsed_time # how long it is has been since a zombie was created
    index = animation_index at
    "sprites/zombie-#{index}.png" # string interpolation to iterate through images
  end
end

$protect_the_puppies_from_the_zombies = ProtectThePuppiesFromTheZombies.new

def tick args
  $protect_the_puppies_from_the_zombies.grid    = args.grid
  $protect_the_puppies_from_the_zombies.inputs  = args.inputs
  $protect_the_puppies_from_the_zombies.state    = args.state
  $protect_the_puppies_from_the_zombies.outputs = args.outputs
  $protect_the_puppies_from_the_zombies.tick
  tick_instructions args, "How to get the mouse position and translate it to an x, y position using .vector_x and .vector_y. CLICK to play."
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Mouse Move Paint App - main.rb link

# ./samples/05_mouse/03_mouse_move_paint_app/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - Floor: Method that returns an integer number smaller than or equal to the original with no decimal.

   For example, if we have a variable, a = 13.7, and we called floor on it, it would look like this...
   puts a.floor()
   which would print out 13.
   (There is also a ceil method, which returns an integer number greater than or equal to the original
   with no decimal. If we had called ceil on the variable a, the result would have been 14.)

 Reminders:

 - Hashes: Collection of unique keys and their corresponding values. The value can be found
   using their keys.

   For example, if we have a "numbers" hash that stores numbers in English as the
   key and numbers in Spanish as the value, we'd have a hash that looks like this...
   numbers = { "one" => "uno", "two" => "dos", "three" => "tres" }
   and on it goes.

   Now if we wanted to find the corresponding value of the "one" key, we could say
   puts numbers["one"]
   which would print "uno" to the console.

 - args.state.new_entity: Used when we want to create a new object, like a sprite or button.
   In this sample app, new_entity is used to create a new button that clears the grid.
   (Remember, you can use state to define ANY property and it will be retained across frames.)

 - args.inputs.mouse.click.point.(x|y): The x and y location of the mouse.

 - args.inputs.mouse.click.point.created_at: The frame the mouse click occurred in.

 - args.outputs.labels: An array. The values in the array generate a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGN, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.

 - ARRAY#inside_rect?: Returns true or false depending on if the point is inside the rect.

=end

# This sample app shows an empty grid that the user can paint on.
# To paint, the user must keep their mouse presssed and drag it around the grid.
# The "clear" button allows users to clear the grid so they can start over.

class PaintApp
  attr_accessor :inputs, :state, :outputs, :grid, :args

  # Runs methods necessary for the game to function properly.
  def tick
    print_title
    add_grid
    check_click
    draw_buttons
  end

  # Prints the title onto the screen by using a label.
  # Also separates the title from the grid with a line as a horizontal separator.
  def print_title
    args.outputs.labels << [ 640, 700, 'Paint!', 0, 1 ]
    outputs.lines << horizontal_separator(660, 0, 1280)
  end

  # Sets the starting position, ending position, and color for the horizontal separator.
  # The starting and ending positions have the same y values.
  def horizontal_separator y, x, x2
    [x, y, x2, y, 150, 150, 150]
  end

  # Sets the starting position, ending position, and color for the vertical separator.
  # The starting and ending positions have the same x values.
  def vertical_separator x, y, y2
    [x, y, x, y2, 150, 150, 150]
  end

  # Outputs a border and a grid containing empty squares onto the screen.
  def add_grid

    # Sets the x, y, height, and width of the grid.
    # There are 31 horizontal lines and 31 vertical lines in the grid.
    # Feel free to count them yourself before continuing!
    x, y, h, w = 640 - 500/2, 640 - 500, 500, 500 # calculations done so the grid appears in screen's center
    lines_h = 31
    lines_v = 31

    # Sets values for the grid's border, grid lines, and filled squares.
    # The filled_squares variable is initially set to an empty array.
    state.grid_border ||= [ x, y, h, w ] # definition of grid's outer border
    state.grid_lines ||= draw_grid(x, y, h, w, lines_h, lines_v) # calls draw_grid method
    state.filled_squares ||= [] # there are no filled squares until the user fills them in

    # Outputs the grid lines, border, and filled squares onto the screen.
    outputs.lines.concat state.grid_lines
    outputs.borders << state.grid_border
    outputs.solids << state.filled_squares
  end

  # Draws the grid by adding in vertical and horizontal separators.
  def draw_grid x, y, h, w, lines_h, lines_v

    # The grid starts off empty.
    grid = []

    # Calculates the placement and adds horizontal lines or separators into the grid.
    curr_y = y # start at the bottom of the box
    dist_y = h / (lines_h + 1) # finds distance to place horizontal lines evenly throughout 500 height of grid
    lines_h.times do
      curr_y += dist_y # increment curr_y by the distance between the horizontal lines
      grid << horizontal_separator(curr_y, x, x + w - 1) # add a separator into the grid
    end

    # Calculates the placement and adds vertical lines or separators into the grid.
    curr_x = x # now start at the left of the box
    dist_x = w / (lines_v + 1) # finds distance to place vertical lines evenly throughout 500 width of grid
    lines_v.times do
      curr_x += dist_x # increment curr_x by the distance between the vertical lines
      grid << vertical_separator(curr_x, y + 1, y  + h) # add separator
    end

    # paint_grid uses a hash to assign values to keys.
    state.paint_grid ||= {"x" => x, "y" => y, "h" => h, "w" => w, "lines_h" => lines_h,
                          "lines_v" => lines_v, "dist_x" => dist_x,
                          "dist_y" => dist_y }

    return grid
  end

  # Checks if the user is keeping the mouse pressed down and sets the mouse_hold variable accordingly using boolean values.
  # If the mouse is up, the user cannot drag the mouse.
  def check_click
    if inputs.mouse.down #is mouse up or down?
      state.mouse_held = true # mouse is being held down
    elsif inputs.mouse.up # if mouse is up
    state.mouse_held = false # mouse is not being held down or dragged
      state.mouse_dragging = false
    end

    if state.mouse_held &&    # mouse needs to be down
      !inputs.mouse.click &&     # must not be first click
      ((inputs.mouse.previous_click.point.x - inputs.mouse.position.x).abs > 15) # Need to move 15 pixels before "drag"
      state.mouse_dragging = true
    end

    # If the user clicks their mouse inside the grid, the search_lines method is called with a click input type.
    if ((inputs.mouse.click) && (inputs.mouse.click.point.inside_rect? state.grid_border))
      search_lines(inputs.mouse.click.point, :click)

    # If the user drags their mouse inside the grid, the search_lines method is called with a drag input type.
    elsif ((state.mouse_dragging) && (inputs.mouse.position.inside_rect? state.grid_border))
      search_lines(inputs.mouse.position, :drag)
    end
  end

  # Sets the definition of a grid box and handles user input to fill in or clear grid boxes.
  def search_lines (point, input_type)
    point.x -= state.paint_grid["x"] # subtracts the value assigned to the "x" key in the paint_grid hash
    point.y -= state.paint_grid["y"] # subtracts the value assigned to the "y" key in the paint_grid hash

    # Remove code following the .floor and see what happens when you try to fill in grid squares
    point.x = (point.x / state.paint_grid["dist_x"]).floor * state.paint_grid["dist_x"]
    point.y = (point.y / state.paint_grid["dist_y"]).floor * state.paint_grid["dist_y"]

    point.x += state.paint_grid["x"]
    point.y += state.paint_grid["y"]

    # Sets definition of a grid box, meaning its x, y, width, and height.
    # Floor is called on the point.x and point.y variables.
    # Ceil method is called on values of the distance hash keys, setting the width and height of a box.
    grid_box = [ point.x.floor, point.y.floor, state.paint_grid["dist_x"].ceil, state.paint_grid["dist_y"].ceil ]

    if input_type == :click # if user clicks their mouse
      if state.filled_squares.include? grid_box # if grid box is already filled in
        state.filled_squares.delete grid_box # box is cleared and removed from filled_squares
      else
        state.filled_squares << grid_box # otherwise, box is filled in and added to filled_squares
      end
    elsif input_type == :drag # if user drags mouse
      unless state.filled_squares.include? grid_box # unless the grid box dragged over is already filled in
        state.filled_squares << grid_box # the box is filled in and added to filled_squares
      end
    end
  end

  # Creates and outputs a "Clear" button on the screen using a label and a border.
  # If the button is clicked, the filled squares are cleared, making the filled_squares collection empty.
  def draw_buttons
    x, y, w, h = 390, 50, 240, 50
    state.clear_button        ||= state.new_entity(:button_with_fade)

    # The x and y positions are set to display the label in the center of the button.
    # Try changing the first two parameters to simply x, y and see what happens to the text placement!
    state.clear_button.label  ||= [x + w.half, y + h.half + 10, "Clear", 0, 1] # placed in center of border
    state.clear_button.border ||= [x, y, w, h]

    # If the mouse is clicked inside the borders of the clear button,
    # the filled_squares collection is emptied and the squares are cleared.
    if inputs.mouse.click && inputs.mouse.click.point.inside_rect?(state.clear_button.border)
      state.clear_button.clicked_at = inputs.mouse.click.created_at # time (frame) the click occurred
      state.filled_squares.clear
      inputs.mouse.previous_click = nil
    end

    outputs.labels << state.clear_button.label
    outputs.borders << state.clear_button.border

    # When the clear button is clicked, the color of the button changes
    # and the transparency changes, as well. If you change the time from
    # 0.25.seconds to 1.25.seconds or more, the change will last longer.
    if state.clear_button.clicked_at
      outputs.solids << [x, y, w, h, 0, 180, 80, 255 * state.clear_button.clicked_at.ease(0.25.seconds, :flip)]
    end
  end
end

$paint_app = PaintApp.new

def tick args
  $paint_app.inputs = args.inputs
  $paint_app.state = args.state
  $paint_app.grid = args.grid
  $paint_app.args = args
  $paint_app.outputs = args.outputs
  $paint_app.tick
  tick_instructions args, "How to create a simple paint app. CLICK and HOLD to draw."
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Coordinate Systems - main.rb link

# ./samples/05_mouse/04_coordinate_systems/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - args.inputs.mouse.click.position: Coordinates of the mouse's position on the screen.
   Unlike args.inputs.mouse.click.point, the mouse does not need to be pressed down for
   position to know the mouse's coordinates.
   For more information about the mouse, go to mygame/documentation/07-mouse.md.

 Reminders:

 - args.inputs.mouse.click: This property will be set if the mouse was clicked.

 - args.inputs.mouse.click.point.(x|y): The x and y location of the mouse.

 - String interpolation: Uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

   In this sample app, string interpolation is used to show the current position of the mouse
   in a label.

 - args.outputs.labels: An array that generates a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGN, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.

 - args.outputs.solids: An array that generates a solid.
   The parameters are [X, Y, WIDTH, HEIGHT, RED, GREEN, BLUE, ALPHA]
   For more information about solids, go to mygame/documentation/03-solids-and-borders.md.

 - args.outputs.lines: An array that generates a line.
   The parameters are [X, Y, X2, Y2, RED, GREEN, BLUE, ALPHA]
   For more information about lines, go to mygame/documentation/04-lines.md.

=end

# This sample app shows a coordinate system or grid. The user can move their mouse around the screen and the
# coordinates of their position on the screen will be displayed. Users can choose to view one quadrant or
# four quadrants by pressing the button.

def tick args

  # The addition and subtraction in the first two parameters of the label and solid
  # ensure that the outputs don't overlap each other. Try removing them and see what happens.
  pos = args.inputs.mouse.position # stores coordinates of mouse's position
  args.outputs.labels << [pos.x + 10, pos.y + 10, "#{pos}"] # outputs label of coordinates
  args.outputs.solids << [pos.x -  2, pos.y - 2, 5, 5] # outputs small blackk box placed where mouse is hovering

  button = [0, 0, 370, 50] # sets definition of toggle button
  args.outputs.borders << button # outputs button as border (not filled in)
  args.outputs.labels << [10, 35, "click here toggle coordinate system"] # label of button
  args.outputs.lines << [    0, -720,    0, 720] # vertical line dividing quadrants
  args.outputs.lines << [-1280,    0, 1280,   0] # horizontal line dividing quadrants

  if args.inputs.mouse.click # if the user clicks the mouse
    pos = args.inputs.mouse.click.point # pos's value is point where user clicked (coordinates)
    if pos.inside_rect? button # if the click occurred inside the button
      if args.grid.name == :bottom_left # if the grid shows bottom left as origin
        args.grid.origin_center! # origin will be shown in center
      else
        args.grid.origin_bottom_left! # otherwise, the view will change to show bottom left as origin
      end
    end
  end

  tick_instructions args, "Sample app shows the two supported coordinate systems in Game Toolkit."
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Clicking Buttons - main.rb link

# ./samples/05_mouse/05_clicking_buttons/app/main.rb
def tick args
  # create buttons
  args.state.buttons ||= [
    create_button(args, id: :button_1, row: 0, col: 0, text: "button 1"),
    create_button(args, id: :button_2, row: 1, col: 0, text: "button 2"),
    create_button(args, id: :clear,    row: 2, col: 0, text: "clear")
  ]

  # render button's border and label
  args.outputs.primitives << args.state.buttons.map do |b|
    b.primitives
  end

  # render center label if the text is set
  if args.state.center_label_text
    args.outputs.labels << { x: 640,
                             y: 360,
                             text: args.state.center_label_text,
                             alignment_enum: 1,
                             vertical_alignment_enum: 1 }
  end

  # if the mouse is clicked, see if the mouse click intersected
  # with a button
  if args.inputs.mouse.click
    button = args.state.buttons.find do |b|
      args.inputs.mouse.intersect_rect? b
    end

    # update the center label text based on button clicked
    case button.id
    when :button_1
      args.state.center_label_text = "button 1 was clicked"
    when :button_2
      args.state.center_label_text = "button 2 was clicked"
    when :clear
      args.state.center_label_text = nil
    end
  end
end

def create_button args, id:, row:, col:, text:;
  # args.layout.rect(row:, col:, w:, h:) is method that will
  # return a rectangle inside of a grid with 12 rows and 24 columns
  rect = args.layout.rect row: row, col: col, w: 3, h: 1

  # get senter of rect for label
  center = args.geometry.rect_center_point rect

  {
    id: id,
    x: rect.x,
    y: rect.y,
    w: rect.w,
    h: rect.h,
    primitives: [
      {
        x: rect.x,
        y: rect.y,
        w: rect.w,
        h: rect.h,
        primitive_marker: :border
      },
      {
        x: center.x,
        y: center.y,
        text: text,
        size_enum: -1,
        alignment_enum: 1,
        vertical_alignment_enum: 1,
        primitive_marker: :label
      }
    ]
  }
end

$gtk.reset

Save Load link

Save Load Game - main.rb link

# ./samples/06_save_load/01_save_load_game/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - Symbol (:): Ruby object with a name and an internal ID. Symbols are useful
   because with a given symbol name, you can refer to the same object throughout
   a Ruby program.

   In this sample app, we're using symbols for our buttons. We have buttons that
   light fires, save, load, etc. Each of these buttons has a distinct symbol like
   :light_fire, :save_game, :load_game, etc.

 - to_sym: Returns the symbol corresponding to the given string; creates the symbol
   if it does not already exist.
   For example,
   'car'.to_sym
   would return the symbol :car.

 - last: Returns the last element of an array.

 Reminders:

 - num1.lesser(num2): finds the lower value of the given options.
   For example, in the statement
   a = 4.lesser(3)
   3 has a lower value than 4, which means that the value of a would be set to 3,
   but if the statement had been
   a = 4.lesser(5)
   4 has a lower value than 5, which means that the value of a would be set to 4.

 - num1.fdiv(num2): returns the float division (will have a decimal) of the two given numbers.
   For example, 5.fdiv(2) = 2.5 and 5.fdiv(5) = 1.0

 - String interpolation: uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

 - args.outputs.labels: An array. Values generate a label.
   Parameters are [X, Y, TEXT, SIZE, ALIGN, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information, go to mygame/documentation/02-labels.md.

 - ARRAY#inside_rect?: An array with at least two values is considered a point. An array
   with at least four values is considered a rect. The inside_rect? function returns true
   or false depending on if the point is inside the rect.

=end

# This code allows users to perform different tasks, such as saving and loading the game.
# Users also have options to reset the game and light a fire.

class TextedBasedGame

  # Contains methods needed for game to run properly.
  # Increments tick count by 1 each time it runs (60 times in a single second)
  def tick
    default
    show_intro
    state.engine_tick_count += 1
    tick_fire
  end

  # Sets default values.
  # The ||= ensures that a variable's value is only set to the value following the = sign
  # if the value has not already been set before. Intialization happens only in the first frame.
  def default
    state.engine_tick_count ||= 0
    state.active_module     ||= :room
    state.fire_progress     ||= 0
    state.fire_ready_in     ||= 10
    state.previous_fire     ||= :dead
    state.fire              ||= :dead
  end

  def show_intro
    return unless state.engine_tick_count == 0 # return unless the game just started
    set_story_line "awake." # calls set_story_line method, sets to "awake"
  end

  # Sets story line.
  def set_story_line story_line
    state.story_line    = story_line # story line set to value of parameter
    state.active_module = :alert # active module set to alert
  end

  # Clears story line.
  def clear_storyline
    state.active_module = :none # active module set to none
    state.story_line = nil # story line is cleared, set to nil (or empty)
  end

  # Determines fire progress (how close the fire is to being ready to light).
  def tick_fire
    return if state.active_module == :alert # return if active module is alert
    state.fire_progress += 1 # increment fire progress
    # fire_ready_in is 10. The fire_progress is either the current value or 10, whichever has a lower value.
    state.fire_progress = state.fire_progress.lesser(state.fire_ready_in)
  end

  # Sets the value of fire (whether it is dead or roaring), and the story line
  def light_fire
    return unless fire_ready? # returns unless the fire is ready to be lit
    state.fire = :roaring # fire is lit, set to roaring
    state.fire_progress = 0 # the fire progress returns to 0, since the fire has been lit
    if state.fire != state.previous_fire
      set_story_line "the fire is #{state.fire}." # the story line is set using string interpolation
      state.previous_fire = state.fire
    end
  end

  # Checks if the fire is ready to be lit. Returns a boolean value.
  def fire_ready?
    # If fire_progress (value between 0 and 10) is equal to fire_ready_in (value of 10),
    # the fire is ready to be lit.
    state.fire_progress == state.fire_ready_in
  end

  # Divides the value of the fire_progress variable by 10 to determine how close the user is to
  # being able to light a fire.
  def light_fire_progress
    state.fire_progress.fdiv(10) # float division
  end

  # Defines fire as the state.fire variable.
  def fire
    state.fire
  end

  # Sets the title of the room.
  def room_title
    return "a room that is dark" if state.fire == :dead # room is dark if the fire is dead
    return "a room that is lit" # room is lit if the fire is not dead
  end

  # Sets the active_module to room.
  def go_to_room
    state.active_module = :room
  end

  # Defines active_module as the state.active_module variable.
  def active_module
    state.active_module
  end

  # Defines story_line as the state.story_line variable.
  def story_line
    state.story_line
  end

  # Update every 60 frames (or every second)
  def should_tick?
    Kernel.tick_count.zmod?(60)
  end

  # Sets the value of the game state provider.
  def initialize game_state_provider
    @game_state_provider = game_state_provider
  end

  # Defines the game state.
  # Any variable prefixed with an @ symbol is an instance variable.
  def state
    @game_state_provider.state
  end

  # Saves the state of the game in a text file called game_state.txt.
  def save
    $gtk.serialize_state('game_state.txt', state)
  end

  # Loads the game state from the game_state.txt text file.
  # If the load is unsuccessful, the user is informed since the story line indicates the failure.
  def load
    parsed_state = $gtk.deserialize_state('game_state.txt')
    if !parsed_state
      set_story_line "no game to load. press save first."
    else
      $gtk.args.state = parsed_state
    end
  end

  # Resets the game.
  def reset
    $gtk.reset
  end
end

class TextedBasedGamePresenter
  attr_accessor :state, :outputs, :inputs

  # Creates empty collection called highlights.
  # Calls methods necessary to run the game.
  def tick
    state.layout.highlights ||= []
    game.tick if game.should_tick?
    render
    process_input
  end

  # Outputs a label of the tick count (passage of time) and calls all render methods.
  def render
    outputs.labels << [10, 30, Kernel.tick_count]
    render_alert
    render_room
    render_highlights
  end

  # Outputs a label onto the screen that shows the story line, and also outputs a "close" button.
  def render_alert
    return unless game.active_module == :alert

    outputs.labels << [640, 480, game.story_line, 5, 1]  # outputs story line label
    outputs.primitives << button(:alert_dismiss, 490, 380, "close")  # positions "close" button under story line
  end

  def render_room
    return unless game.active_module == :room
    outputs.labels << [640, 700, game.room_title, 4, 1] # outputs room title label at top of screen

    # The parameters for these outputs are (symbol, x, y, text, value/percentage) and each has a y value
    # that positions it 60 pixels lower than the previous output.

    # outputs the light_fire_progress bar, uses light_fire_progress for its percentage (which changes bar's appearance)
    outputs.primitives << progress_bar(:light_fire, 490, 600, "light fire", game.light_fire_progress)
    outputs.primitives << button(       :save_game, 490, 540, "save") # outputs save button
    outputs.primitives << button(       :load_game, 490, 480, "load") # outputs load button
    outputs.primitives << button(      :reset_game, 490, 420, "reset") # outputs reset button
    outputs.labels << [640, 30, "the fire is #{game.fire}", 0, 1] # outputs fire label at bottom of screen
  end

  # Outputs a collection of highlights using an array to set their values, and also rejects certain values from the collection.
  def render_highlights
    state.layout.highlights.each do |h| # for each highlight in the collection
        h.lifetime -= 1 # decrease the value of its lifetime
      end

      outputs.solids << state.layout.highlights.map do |h| # outputs highlights collection
        [h.x, h.y, h.w, h.h, h.color, 255 * h.lifetime / h.max_lifetime] # sets definition for each highlight
        # transparency changes; divide lifetime by max_lifetime, multiply result by 255
      end

      # reject highlights from collection that have no remaining lifetime
      state.layout.highlights = state.layout.highlights.reject { |h| h.lifetime <= 0 }
  end

  # Checks whether or not a button was clicked.
  # Returns a boolean value.
  def process_input
    button = button_clicked? # calls button_clicked? method
  end

  # Returns a boolean value.
  # Finds the button that was clicked from the button list and determines what method to call.
  # Adds a highlight to the highlights collection.
  def button_clicked?
    return nil unless click_pos # return nil unless click_pos holds coordinates of mouse click
      button = @button_list.find do |k, v| # goes through button_list to find button clicked
        click_pos.inside_rect? v[:primitives].last.rect # was the mouse clicked inside the rect of button?
      end
      return unless button # return unless a button was clicked
      method_to_call = "#{button[0]}_clicked".to_sym # sets method_to_call to symbol (like :save_game or :load_game)
      if self.respond_to? method_to_call # returns true if self responds to the given method (method actually exists)
        border = button[1][:primitives].last # sets border definition using value of last key in button list hash

        # declares each highlight as a new entity, sets properties
        state.layout.highlights << state.new_entity(:highlight) do |h|
            h.x = border.x
            h.y = border.y
            h.w = border.w
            h.h = border.h
            h.max_lifetime = 10
            h.lifetime = h.max_lifetime
            h.color = [120, 120, 180] # sets color to shade of purple
          end

          self.send method_to_call # invoke method identified by symbol
        else # otherwise, if self doesn't respond to given method
          border = button[1][:primitives].last # sets border definition using value of last key in hash

          # declares each highlight as a new entity, sets properties
          state.layout.highlights << state.new_entity(:highlight) do |h|
            h.x = border.x
            h.y = border.y
            h.w = border.w
            h.h = border.h
            h.max_lifetime = 4 # different max_lifetime than the one set if respond_to? had been true
            h.lifetime = h.max_lifetime
            h.color = [120, 80, 80] # sets color to dark color
          end

          # instructions for users on how to add the missing method_to_call to the code
          puts "It looks like #{method_to_call} doesn't exists on TextedBasedGamePresenter. Please add this method:"
          puts "Just copy the code below and put it in the #{TextedBasedGamePresenter} class definition."
          puts ""
          puts "```"
          puts "class TextedBasedGamePresenter <--- find this class and put the method below in it"
          puts ""
          puts "  def #{method_to_call}"
          puts "    puts 'Yay that worked!'"
          puts "  end"
          puts ""
          puts "end <-- make sure to put the #{method_to_call} method in between the `class` word and the final `end` statement."
          puts "```"
          puts ""
      end
  end

  # Returns the position of the mouse when it is clicked.
  def click_pos
    return nil unless inputs.mouse.click # returns nil unless the mouse was clicked
    return inputs.mouse.click.point # returns location of mouse click (coordinates)
  end

  # Creates buttons for the button_list and sets their values using a hash (uses symbols as keys)
  def button id, x, y, text
    @button_list[id] ||= { # assigns values to hash keys
      id: id,
      text: text,
      primitives: [
        [x + 10, y + 30, text, 2, 0].label, # positions label inside border
        [x, y, 300, 50].border,             # sets definition of border
      ]
    }

    @button_list[id][:primitives] # returns label and border for buttons
  end

  # Creates a progress bar (used for lighting the fire) and sets its values.
  def progress_bar id, x, y, text, percentage
    @button_list[id] = { # assigns values to hash keys
      id: id,
      text: text,
      primitives: [
        [x, y, 300, 50, 100, 100, 100].solid, # sets definition for solid (which fills the bar with gray)
        [x + 10, y + 30, text, 2, 0].label, # sets definition for label, positions inside border
        [x, y, 300, 50].border, # sets definition of border
      ]
    }

    # Fills progress bar based on percentage. If the fire was ready to be lit (100%) and we multiplied by
    # 100, only 1/3 of the bar would only be filled in. 200 would cause only 2/3 to be filled in.
    @button_list[id][:primitives][0][2] = 300 * percentage
    @button_list[id][:primitives]
  end

  # Defines the game.
  def game
    @game
  end

  # Initalizes the game and creates an empty list of buttons.
  def initialize
    @game = TextedBasedGame.new self
    @button_list ||= {}
  end

  # Clears the storyline and takes the user to the room.
  def alert_dismiss_clicked
    game.clear_storyline
    game.go_to_room
  end

  # Lights the fire when the user clicks the "light fire" option.
  def light_fire_clicked
    game.light_fire
  end

  # Saves the game when the user clicks the "save" option.
  def save_game_clicked
    game.save
  end

  # Resets the game when the user clicks the "reset" option.
  def reset_game_clicked
    game.reset
  end

  # Loads the game when the user clicks the "load" option.
  def load_game_clicked
    game.load
  end
end

$text_based_rpg = TextedBasedGamePresenter.new

def tick args
  $text_based_rpg.state = args.state
  $text_based_rpg.outputs = args.outputs
  $text_based_rpg.inputs = args.inputs
  $text_based_rpg.tick
end

Advanced Audio link

Audio Mixer - main.rb link

# ./samples/07_advanced_audio/01_audio_mixer/app/main.rb
# these are the properties that you can sent on args.audio
def spawn_new_sound args, name, path
  # Spawn randomly in an area that won't be covered by UI.
  screenx = (rand * 600.0) + 200.0
  screeny = (rand * 400.0) + 100.0

  id = new_sound_id! args
  # you can hang anything on the audio hashes you want, so we store the
  #  actual screen position in here for convenience.
  args.audio[id] = {
    name: name,
    input: path,
    screenx: screenx,
    screeny: screeny,
    x: ((screenx / 1279.0) * 2.0) - 1.0,  # scale to -1.0 - 1.0 range
    y: ((screeny / 719.0) * 2.0) - 1.0,   # scale to -1.0 - 1.0 range
    z: 0.0,
    gain: 1.0,
    pitch: 1.0,
    looping: true,
    paused: false
  }

  args.state.selected = id
end

# these are values you can change on the ~args.audio~ data structure
def input_panel args
  return unless args.state.panel
  return if args.state.dragging

  audio_entry = args.audio[args.state.selected]
  results = args.state.panel

  if args.state.mouse_state == :held && args.inputs.mouse.position.inside_rect?(results.pitch_slider_rect.rect)
    audio_entry.pitch = 2.0 * ((args.inputs.mouse.x - results.pitch_slider_rect.rect.x).to_f / (results.pitch_slider_rect.rect.w - 1.0))
  elsif args.state.mouse_state == :held && args.inputs.mouse.position.inside_rect?(results.playtime_slider_rect.rect)
    audio_entry.playtime = audio_entry.length_ * ((args.inputs.mouse.x - results.playtime_slider_rect.rect.x).to_f / (results.playtime_slider_rect.rect.w - 1.0))
  elsif args.state.mouse_state == :held && args.inputs.mouse.position.inside_rect?(results.gain_slider_rect.rect)
    audio_entry.gain = (args.inputs.mouse.x - results.gain_slider_rect.rect.x).to_f / (results.gain_slider_rect.rect.w - 1.0)
  elsif args.inputs.mouse.click && args.inputs.mouse.position.inside_rect?(results.looping_checkbox_rect.rect)
    audio_entry.looping = !audio_entry.looping
  elsif args.inputs.mouse.click && args.inputs.mouse.position.inside_rect?(results.paused_checkbox_rect.rect)
    audio_entry.paused = !audio_entry.paused
  elsif args.inputs.mouse.click && args.inputs.mouse.position.inside_rect?(results.delete_button_rect.rect)
    args.audio.delete args.state.selected
  end
end

def render_sources args
  args.outputs.primitives << args.audio.keys.map do |k|
    s = args.audio[k]

    isselected = (k == args.state.selected)

    color = isselected ? [ 0, 255, 0, 255 ] : [ 0, 0, 255, 255 ]
    [
      [s.screenx, s.screeny, args.state.boxsize, args.state.boxsize, *color].solid,

      {
        x: s.screenx + args.state.boxsize.half,
        y: s.screeny,
        text: s.name,
        r: 255,
        g: 255,
        b: 255,
        alignment_enum: 1
      }.label!
    ]
  end
end

def playtime_str t
  return "" unless t
  minutes = (t / 60.0).floor
  seconds = t - (minutes * 60.0).to_f
  return minutes.to_s + ':' + seconds.floor.to_s + ((seconds - seconds.floor).to_s + "000")[1..3]
end

def label_with_drop_shadow x, y, text
  [
    { x: x + 1, y: y + 1, text: text, vertical_alignment_enum: 1, alignment_enum: 1, r:   0, g:   0, b:   0 }.label!,
    { x: x + 2, y: y + 0, text: text, vertical_alignment_enum: 1, alignment_enum: 1, r:   0, g:   0, b:   0 }.label!,
    { x: x + 0, y: y + 1, text: text, vertical_alignment_enum: 1, alignment_enum: 1, r: 200, g: 200, b: 200 }.label!
  ]
end

def check_box opts = {}
  checkbox_template = opts.args.layout.rect(w: 0.5, h: 0.5, col: 2)
  final_rect = checkbox_template.center_inside_rect_y(opts.args.layout.rect(row: opts.row, col: opts.col))
  color = { r:   0, g:   0, b:   0 }
  color = { r: 255, g: 255, b: 255 } if opts.checked

  {
    rect: final_rect,
    primitives: [
      (final_rect.to_solid color)
    ]
  }
end

def progress_bar opts = {}
  outer_rect  = opts.args.layout.rect(row: opts.row, col: opts.col, w: 5, h: 1)
  color = opts.percentage * 255
  baseline_progress_bar = opts.args
                              .layout
                              .rect(w: 5, h: 0.5)

  final_rect = baseline_progress_bar.center_inside_rect(outer_rect)
  center = final_rect.rect_center_point

  {
    rect: final_rect,
    primitives: [
      final_rect.merge(r: color, g: color, b: color, a: 128).solid!,
      label_with_drop_shadow(center.x, center.y, opts.text)
    ]
  }
end

def panel_primitives args, audio_entry
  results = { primitives: [] }

  return results unless audio_entry

  # this uses DRGTK's layout apis to layout the controls
  # imagine the screen is split into equal cells (24 cells across, 12 cells up and down)
  # args.layout.rect returns a hash which we merge values with to create primitives
  # using args.layout.rect removes the need for pixel pushing

  # args.outputs.debug << args.layout.debug_primitives(r: 255, g: 255, b: 255)

  white_color = { r: 255, g: 255, b: 255 }
  label_style = white_color.merge(vertical_alignment_enum: 1)

  # panel background
  results.primitives << args.layout.rect(row: 0, col: 0, w: 7, h: 6, include_col_gutter: true, include_row_gutter: true)
                                   .border!(r: 255, g: 255, b: 255)

  # title
  results.primitives << args.layout.point(row: 0, col: 3.5, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text:           "Source #{args.state.selected} (#{args.audio[args.state.selected].name})",
                                          size_enum:      3,
                                          alignment_enum: 1)

  # seperator line
  results.primitives << args.layout.rect(row: 1, col: 0, w: 7, h: 0)
                                   .line!(white_color)

  # screen location
  results.primitives << args.layout.point(row: 1.0, col: 0, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "screen:")

  results.primitives << args.layout.point(row: 1.0, col: 2, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "(#{audio_entry.screenx.to_i}, #{audio_entry.screeny.to_i})")

  # position
  results.primitives << args.layout.point(row: 1.5, col: 0, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "position:")

  results.primitives << args.layout.point(row: 1.5, col: 2, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "(#{audio_entry[:x].round(5).to_s[0..6]}, #{audio_entry[:y].round(5).to_s[0..6]})")

  results.primitives << args.layout.point(row: 2.0, col: 0, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "pitch:")

  results.pitch_slider_rect = progress_bar(row: 2.0, col: 2,
                                           percentage: audio_entry.pitch / 2.0,
                                           text: "#{audio_entry.pitch.to_sf}",
                                           args: args)

  results.primitives << results.pitch_slider_rect.primitives

  results.primitives << args.layout.point(row: 2.5, col: 0, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "playtime:")

  results.playtime_slider_rect = progress_bar(args: args,
                                              row:  2.5,
                                              col:  2,
                                              percentage: (audio_entry.playtime || 1) / (audio_entry.length_ || 1),
                                              text: "#{playtime_str(audio_entry.playtime)} / #{playtime_str(audio_entry.length_)}")

  results.primitives << results.playtime_slider_rect.primitives

  results.primitives << args.layout.point(row: 3.0, col: 0, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "gain:")

  results.gain_slider_rect = progress_bar(args: args,
                                          row:  3.0,
                                          col:  2,
                                          percentage: audio_entry.gain,
                                          text: "#{audio_entry.gain.to_sf}")

  results.primitives << results.gain_slider_rect.primitives


  results.primitives << args.layout.point(row: 3.5, col: 0, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "looping:")

  checkbox_template = args.layout.rect(w: 0.5, h: 0.5, col: 2)

  results.looping_checkbox_rect = check_box(args: args, row: 3.5, col: 2, checked: audio_entry.looping)
  results.primitives << results.looping_checkbox_rect.primitives

  results.primitives << args.layout.point(row: 4.0, col: 0, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "paused:")

  checkbox_template = args.layout.rect(w: 0.5, h: 0.5, col: 2)

  results.paused_checkbox_rect = check_box(args: args, row: 4.0, col: 2, checked: !audio_entry.paused)
  results.primitives << results.paused_checkbox_rect.primitives

  results.delete_button_rect = { rect: args.layout.rect(row: 5, col: 0, w: 7, h: 1) }

  results.primitives << results.delete_button_rect.rect.to_solid(r: 180)

  results.primitives << args.layout.point(row: 5, col: 3.5, row_anchor: 0.5)
                                   .merge(label_style)
                                   .merge(text: "DELETE", alignment_enum: 1)

  return results
end

def render_panel args
  args.state.panel = nil
  audio_entry = args.audio[args.state.selected]
  return unless audio_entry

  mouse_down = (args.state.mouse_held >= 0)
  args.state.panel = panel_primitives args, audio_entry
  args.outputs.primitives << args.state.panel.primitives
end

def new_sound_id! args
  args.state.sound_id ||= 0
  args.state.sound_id  += 1
  args.state.sound_id
end

def render_launcher args
  args.outputs.primitives << args.state.spawn_sound_buttons.map(&:primitives)
end

def render_ui args
  render_launcher args
  render_panel args
end

def tick args
  defaults args
  render args
  input args
end

def input args
  if !args.audio[args.state.selected]
    args.state.selected = nil
    args.state.dragging = nil
  end

  # spawn button and node interaction
  if args.inputs.mouse.click
    spawn_sound_button = args.state.spawn_sound_buttons.find { |b| args.inputs.mouse.inside_rect? b.rect }

    audio_click_key, audio_click_value = args.audio.find do |k, v|
      args.inputs.mouse.inside_rect? [v.screenx, v.screeny, args.state.boxsize, args.state.boxsize]
    end

    if spawn_sound_button
      args.state.selected = nil
      spawn_new_sound args, spawn_sound_button.name, spawn_sound_button.path
    elsif audio_click_key
      args.state.selected = audio_click_key
    end
  end

  if args.state.mouse_state == :held && args.state.selected
    v = args.audio[args.state.selected]
    if args.inputs.mouse.inside_rect? [v.screenx, v.screeny, args.state.boxsize, args.state.boxsize]
      args.state.dragging = args.state.selected
    end

    if args.state.dragging
      s = args.audio[args.state.selected]
      # you can hang anything on the audio hashes you want, so we store the
      #  actual screen position so it doesn't scale weirdly vs your mouse.
      s.screenx = args.inputs.mouse.x - (args.state.boxsize / 2)
      s.screeny = args.inputs.mouse.y - (args.state.boxsize / 2)

      s.screeny = 50 if s.screeny < 50
      s.screeny = (719 - args.state.boxsize) if s.screeny > (719 - args.state.boxsize)
      s.screenx = 0 if s.screenx < 0
      s.screenx = (1279 - args.state.boxsize) if s.screenx > (1279 - args.state.boxsize)

      s.x = ((s.screenx / 1279.0) * 2.0) - 1.0  # scale to -1.0 - 1.0 range
      s.y = ((s.screeny / 719.0) * 2.0) - 1.0   # scale to -1.0 - 1.0 range
    end
  elsif args.state.mouse_state == :released
    args.state.dragging = nil
  end

  input_panel args
end

def defaults args
  args.state.mouse_state      ||= :released
  args.state.dragging_source  ||= false
  args.state.selected         ||= 0
  args.state.next_sound_index ||= 0
  args.state.boxsize          ||= 30
  args.state.sound_files      ||= [
    { name: :tada,   path: "sounds/tada.wav"   },
    { name: :splash, path: "sounds/splash.wav" },
    { name: :drum,   path: "sounds/drum.mp3"   },
    { name: :spring, path: "sounds/spring.wav" },
    { name: :music,  path: "sounds/music.ogg"  }
  ]

  # generate buttons based off the sound collection above
  args.state.spawn_sound_buttons ||= begin
    # create a group of buttons
    # column centered (using col_offset to calculate the column offset)
    # where each item is 2 columns apart
    rects = args.layout.rect_group row:   11,
                                   col_offset: {
                                     count: args.state.sound_files.length,
                                     w:     2
                                   },
                                   dcol:  2,
                                   w:     2,
                                   h:     1,
                                   group: args.state.sound_files

    # now that you have the rects
    # construct the metadata for the buttons
    rects.map do |rect|
      {
        rect: rect,
        name: rect.name,
        path: rect.path,
        primitives: [
          rect.to_border(r: 255, g: 255, b: 255),
          rect.to_label(x: rect.center_x,
                        y: rect.center_y,
                        text: "#{rect.name}",
                        alignment_enum: 1,
                        vertical_alignment_enum: 1,
                        r: 255, g: 255, b: 255)
        ]
      }
    end
  end

  if args.inputs.mouse.up
    args.state.mouse_state = :released
    args.state.dragging_source = false
  elsif args.inputs.mouse.down
    args.state.mouse_state = :held
  end

  args.outputs.background_color = [ 0, 0, 0, 255 ]
end

def render args
  render_ui args
  render_sources args
end

Audio Mixer - server_ip_address.txt link

# ./samples/07_advanced_audio/01_audio_mixer/app/server_ip_address.txt
192.168.1.65

Sound Synthesis - main.rb link

# ./samples/07_advanced_audio/02_sound_synthesis/app/main.rb
begin # region: top level tick methods
  def tick args
    defaults args
    render args
    input args
    process_audio_queue args
  end

  def defaults args
    args.state.sine_waves      ||= {}
    args.state.square_waves    ||= {}
    args.state.saw_tooth_waves ||= {}
    args.state.triangle_waves  ||= {}
    args.state.audio_queue     ||= []
    args.state.buttons         ||= [
      (frequency_buttons args),
      (sine_wave_note_buttons args),
      (bell_buttons args),
      (square_wave_note_buttons args),
      (saw_tooth_wave_note_buttons args),
      (triangle_wave_note_buttons args),
    ].flatten
  end

  def render args
    args.outputs.borders << args.state.buttons.map { |b| b[:border] }
    args.outputs.labels  << args.state.buttons.map { |b| b[:label]  }
  end

  def input args
    args.state.buttons.each do |b|
      if args.inputs.mouse.click && (args.inputs.mouse.click.inside_rect? b[:rect])
        parameter_string = (b.slice :frequency, :note, :octave).map { |k, v| "#{k}: #{v}" }.join ", "
        args.gtk.notify! "#{b[:method_to_call]} #{parameter_string}"
        send b[:method_to_call], args, b
      end
    end

    if args.inputs.mouse.click && (args.inputs.mouse.click.inside_rect? (args.layout.rect(row: 0).yield_self { |r| r.merge y: r.y + r.h.half, h: r.h.half }))
      args.gtk.openurl 'https://www.youtube.com/watch?v=zEzovM5jT-k&ab_channel=AmirRajan'
    end
  end

  def process_audio_queue args
    to_queue = args.state.audio_queue.find_all { |v| v[:queue_at] <= args.tick_count }
    args.state.audio_queue -= to_queue
    to_queue.each { |a| args.audio[a[:id]] = a }

    args.audio.find_all { |k, v| v[:decay_rate] }
      .each     { |k, v| v[:gain] -= v[:decay_rate] }

    sounds_to_stop = args.audio
                       .find_all { |k, v| v[:stop_at] && Kernel.tick_count >= v[:stop_at] }
                       .map { |k, v| k }

    sounds_to_stop.each { |k| args.audio.delete k }
  end
end

begin # region: button definitions, ui layout, callback functions
  def button args, opts
    button_def = opts.merge rect: (args.layout.rect (opts.merge w: 2, h: 1))

    button_def[:border] = button_def[:rect].merge r: 0, g: 0, b: 0

    label_offset_x = 5
    label_offset_y = 30

    button_def[:label]  = button_def[:rect].merge text: opts[:text],
                                                  size_enum: -2.5,
                                                  x: button_def[:rect].x + label_offset_x,
                                                  y: button_def[:rect].y + label_offset_y

    button_def
  end

  def play_sine_wave args, sender
    queue_sine_wave args,
                    frequency: sender[:frequency],
                    duration: 1.seconds,
                    fade_out: true
  end

  def play_note args, sender
    method_to_call = :queue_sine_wave
    method_to_call = :queue_square_wave    if sender[:type] == :square
    method_to_call = :queue_saw_tooth_wave if sender[:type] == :saw_tooth
    method_to_call = :queue_triangle_wave  if sender[:type] == :triangle
    method_to_call = :queue_bell           if sender[:type] == :bell

    send method_to_call, args,
         frequency: (frequency_for note: sender[:note], octave: sender[:octave]),
         duration: 1.seconds,
         fade_out: true
  end

  def frequency_buttons args
    [
      (button args,
              row: 4.0, col: 0, text: "300hz",
              frequency: 300,
              method_to_call: :play_sine_wave),
      (button args,
              row: 5.0, col: 0, text: "400hz",
              frequency: 400,
              method_to_call: :play_sine_wave),
      (button args,
              row: 6.0, col: 0, text: "500hz",
              frequency: 500,
              method_to_call: :play_sine_wave),
    ]
  end

  def sine_wave_note_buttons args
    [
      (button args,
              row: 1.5, col: 2, text: "Sine C4",
              note: :c, octave: 4, type: :sine, method_to_call: :play_note),
      (button args,
              row: 2.5, col: 2, text: "Sine D4",
              note: :d, octave: 4, type: :sine, method_to_call: :play_note),
      (button args,
              row: 3.5, col: 2, text: "Sine E4",
              note: :e, octave: 4, type: :sine, method_to_call: :play_note),
      (button args,
              row: 4.5, col: 2, text: "Sine F4",
              note: :f, octave: 4, type: :sine, method_to_call: :play_note),
      (button args,
              row: 5.5, col: 2, text: "Sine G4",
              note: :g, octave: 4, type: :sine, method_to_call: :play_note),
      (button args,
              row: 6.5, col: 2, text: "Sine A5",
              note: :a, octave: 5, type: :sine, method_to_call: :play_note),
      (button args,
              row: 7.5, col: 2, text: "Sine B5",
              note: :b, octave: 5, type: :sine, method_to_call: :play_note),
      (button args,
              row: 8.5, col: 2, text: "Sine C5",
              note: :c, octave: 5, type: :sine, method_to_call: :play_note),
    ]
  end

  def square_wave_note_buttons args
    [
      (button args,
              row: 1.5, col: 6, text: "Square C4",
              note: :c, octave: 4, type: :square, method_to_call: :play_note),
      (button args,
              row: 2.5, col: 6, text: "Square D4",
              note: :d, octave: 4, type: :square, method_to_call: :play_note),
      (button args,
              row: 3.5, col: 6, text: "Square E4",
              note: :e, octave: 4, type: :square, method_to_call: :play_note),
      (button args,
              row: 4.5, col: 6, text: "Square F4",
              note: :f, octave: 4, type: :square, method_to_call: :play_note),
      (button args,
              row: 5.5, col: 6, text: "Square G4",
              note: :g, octave: 4, type: :square, method_to_call: :play_note),
      (button args,
              row: 6.5, col: 6, text: "Square A5",
              note: :a, octave: 5, type: :square, method_to_call: :play_note),
      (button args,
              row: 7.5, col: 6, text: "Square B5",
              note: :b, octave: 5, type: :square, method_to_call: :play_note),
      (button args,
              row: 8.5, col: 6, text: "Square C5",
              note: :c, octave: 5, type: :square, method_to_call: :play_note),
    ]
  end
  def saw_tooth_wave_note_buttons args
    [
      (button args,
              row: 1.5, col: 8, text: "Saw C4",
              note: :c, octave: 4, type: :saw_tooth, method_to_call: :play_note),
      (button args,
              row: 2.5, col: 8, text: "Saw D4",
              note: :d, octave: 4, type: :saw_tooth, method_to_call: :play_note),
      (button args,
              row: 3.5, col: 8, text: "Saw E4",
              note: :e, octave: 4, type: :saw_tooth, method_to_call: :play_note),
      (button args,
              row: 4.5, col: 8, text: "Saw F4",
              note: :f, octave: 4, type: :saw_tooth, method_to_call: :play_note),
      (button args,
              row: 5.5, col: 8, text: "Saw G4",
              note: :g, octave: 4, type: :saw_tooth, method_to_call: :play_note),
      (button args,
              row: 6.5, col: 8, text: "Saw A5",
              note: :a, octave: 5, type: :saw_tooth, method_to_call: :play_note),
      (button args,
              row: 7.5, col: 8, text: "Saw B5",
              note: :b, octave: 5, type: :saw_tooth, method_to_call: :play_note),
      (button args,
              row: 8.5, col: 8, text: "Saw C5",
              note: :c, octave: 5, type: :saw_tooth, method_to_call: :play_note),
    ]
  end

  def triangle_wave_note_buttons args
    [
      (button args,
              row: 1.5, col: 10, text: "Triangle C4",
              note: :c, octave: 4, type: :triangle, method_to_call: :play_note),
      (button args,
              row: 2.5, col: 10, text: "Triangle D4",
              note: :d, octave: 4, type: :triangle, method_to_call: :play_note),
      (button args,
              row: 3.5, col: 10, text: "Triangle E4",
              note: :e, octave: 4, type: :triangle, method_to_call: :play_note),
      (button args,
              row: 4.5, col: 10, text: "Triangle F4",
              note: :f, octave: 4, type: :triangle, method_to_call: :play_note),
      (button args,
              row: 5.5, col: 10, text: "Triangle G4",
              note: :g, octave: 4, type: :triangle, method_to_call: :play_note),
      (button args,
              row: 6.5, col: 10, text: "Triangle A5",
              note: :a, octave: 5, type: :triangle, method_to_call: :play_note),
      (button args,
              row: 7.5, col: 10, text: "Triangle B5",
              note: :b, octave: 5, type: :triangle, method_to_call: :play_note),
      (button args,
              row: 8.5, col: 10, text: "Triangle C5",
              note: :c, octave: 5, type: :triangle, method_to_call: :play_note),
    ]
  end

  def bell_buttons args
    [
      (button args,
              row: 1.5, col: 4, text: "Bell C4",
              note: :c, octave: 4, type: :bell, method_to_call: :play_note),
      (button args,
              row: 2.5, col: 4, text: "Bell D4",
              note: :d, octave: 4, type: :bell, method_to_call: :play_note),
      (button args,
              row: 3.5, col: 4, text: "Bell E4",
              note: :e, octave: 4, type: :bell, method_to_call: :play_note),
      (button args,
              row: 4.5, col: 4, text: "Bell F4",
              note: :f, octave: 4, type: :bell, method_to_call: :play_note),
      (button args,
              row: 5.5, col: 4, text: "Bell G4",
              note: :g, octave: 4, type: :bell, method_to_call: :play_note),
      (button args,
              row: 6.5, col: 4, text: "Bell A5",
              note: :a, octave: 5, type: :bell, method_to_call: :play_note),
      (button args,
              row: 7.5, col: 4, text: "Bell B5",
              note: :b, octave: 5, type: :bell, method_to_call: :play_note),
      (button args,
              row: 8.5, col: 4, text: "Bell C5",
              note: :c, octave: 5, type: :bell, method_to_call: :play_note),
    ]
  end
end

begin # region: wave generation
  begin # sine wave
    def defaults_sine_wave_for
      { frequency: 440, sample_rate: 48000 }
    end

    def sine_wave_for opts = {}
      opts = defaults_sine_wave_for.merge opts
      frequency   = opts[:frequency]
      sample_rate = opts[:sample_rate]
      period_size = (sample_rate.fdiv frequency).ceil
      period_size.map_with_index do |i|
        Math::sin((2.0 * Math::PI) / (sample_rate.to_f / frequency.to_f) * i)
      end.to_a
    end

    def defaults_queue_sine_wave
      { frequency: 440, duration: 60, gain: 1.0, fade_out: false, queue_in: 0 }
    end

    def queue_sine_wave args, opts = {}
      opts        = defaults_queue_sine_wave.merge opts
      frequency   = opts[:frequency]
      sample_rate = 48000

      sine_wave = sine_wave_for frequency: frequency, sample_rate: sample_rate
      args.state.sine_waves[frequency] ||= sine_wave_for frequency: frequency, sample_rate: sample_rate

      proc = lambda do
        generate_audio_data args.state.sine_waves[frequency], sample_rate
      end

      audio_state = new_audio_state args, opts
      audio_state[:input] = [1, sample_rate, proc]
      queue_audio args, audio_state: audio_state, wave: sine_wave
    end
  end

  begin # region: square wave
    def defaults_square_wave_for
      { frequency: 440, sample_rate: 48000 }
    end

    def square_wave_for opts = {}
      opts = defaults_square_wave_for.merge opts
      sine_wave = sine_wave_for opts
      sine_wave.map do |v|
        if v >= 0
          1.0
        else
          -1.0
        end
      end.to_a
    end

    def defaults_queue_square_wave
      { frequency: 440, duration: 60, gain: 0.3, fade_out: false, queue_in: 0 }
    end

    def queue_square_wave args, opts = {}
      opts        = defaults_queue_square_wave.merge opts
      frequency   = opts[:frequency]
      sample_rate = 48000

      square_wave = square_wave_for frequency: frequency, sample_rate: sample_rate
      args.state.square_waves[frequency] ||= square_wave_for frequency: frequency, sample_rate: sample_rate

      proc = lambda do
        generate_audio_data args.state.square_waves[frequency], sample_rate
      end

      audio_state = new_audio_state args, opts
      audio_state[:input] = [1, sample_rate, proc]
      queue_audio args, audio_state: audio_state, wave: square_wave
    end
  end

  begin # region: saw tooth wave
    def defaults_saw_tooth_wave_for
      { frequency: 440, sample_rate: 48000 }
    end

    def saw_tooth_wave_for opts = {}
      opts = defaults_saw_tooth_wave_for.merge opts
      sine_wave = sine_wave_for opts
      period_size = sine_wave.length
      sine_wave.map_with_index do |v, i|
        (((i % period_size).fdiv period_size) * 2) - 1
      end
    end

    def defaults_queue_saw_tooth_wave
      { frequency: 440, duration: 60, gain: 0.3, fade_out: false, queue_in: 0 }
    end

    def queue_saw_tooth_wave args, opts = {}
      opts        = defaults_queue_saw_tooth_wave.merge opts
      frequency   = opts[:frequency]
      sample_rate = 48000

      saw_tooth_wave = saw_tooth_wave_for frequency: frequency, sample_rate: sample_rate
      args.state.saw_tooth_waves[frequency] ||= saw_tooth_wave_for frequency: frequency, sample_rate: sample_rate

      proc = lambda do
        generate_audio_data args.state.saw_tooth_waves[frequency], sample_rate
      end

      audio_state = new_audio_state args, opts
      audio_state[:input] = [1, sample_rate, proc]
      queue_audio args, audio_state: audio_state, wave: saw_tooth_wave
    end
  end

  begin # region: triangle wave
    def defaults_triangle_wave_for
      { frequency: 440, sample_rate: 48000 }
    end

    def triangle_wave_for opts = {}
      opts = defaults_saw_tooth_wave_for.merge opts
      sine_wave = sine_wave_for opts
      period_size = sine_wave.length
      sine_wave.map_with_index do |v, i|
        ratio = (i.fdiv period_size)
        if ratio <= 0.5
          (ratio * 4) - 1
        else
          ratio -= 0.5
          1 - (ratio * 4)
        end
      end
    end

    def defaults_queue_triangle_wave
      { frequency: 440, duration: 60, gain: 1.0, fade_out: false, queue_in: 0 }
    end

    def queue_triangle_wave args, opts = {}
      opts        = defaults_queue_triangle_wave.merge opts
      frequency   = opts[:frequency]
      sample_rate = 48000

      triangle_wave = triangle_wave_for frequency: frequency, sample_rate: sample_rate
      args.state.triangle_waves[frequency] ||= triangle_wave_for frequency: frequency, sample_rate: sample_rate

      proc = lambda do
        generate_audio_data args.state.triangle_waves[frequency], sample_rate
      end

      audio_state = new_audio_state args, opts
      audio_state[:input] = [1, sample_rate, proc]
      queue_audio args, audio_state: audio_state, wave: triangle_wave
    end
  end

  begin # region: bell
    def defaults_queue_bell
      { frequency: 440, duration: 1.seconds, queue_in: 0 }
    end

    def queue_bell args, opts = {}
      (bell_to_sine_waves (defaults_queue_bell.merge opts)).each { |b| queue_sine_wave args, b }
    end

    def bell_harmonics
      [
        { frequency_ratio: 0.5, duration_ratio: 1.00 },
        { frequency_ratio: 1.0, duration_ratio: 0.80 },
        { frequency_ratio: 2.0, duration_ratio: 0.60 },
        { frequency_ratio: 3.0, duration_ratio: 0.40 },
        { frequency_ratio: 4.2, duration_ratio: 0.25 },
        { frequency_ratio: 5.4, duration_ratio: 0.20 },
        { frequency_ratio: 6.8, duration_ratio: 0.15 }
      ]
    end

    def defaults_bell_to_sine_waves
      { frequency: 440, duration: 1.seconds, queue_in: 0 }
    end

    def bell_to_sine_waves opts = {}
      opts = defaults_bell_to_sine_waves.merge opts
      bell_harmonics.map do |b|
        {
          frequency: opts[:frequency] * b[:frequency_ratio],
          duration:  opts[:duration] * b[:duration_ratio],
          queue_in:  opts[:queue_in],
          gain:      (1.fdiv bell_harmonics.length),
          fade_out:  true
        }
      end
    end
  end

  begin # audio entity construction
    def generate_audio_data sine_wave, sample_rate
      sample_size = (sample_rate.fdiv (1000.fdiv 60)).ceil
      copy_count  = (sample_size.fdiv sine_wave.length).ceil
      sine_wave * copy_count
    end

    def defaults_new_audio_state
      { frequency: 440, duration: 60, gain: 1.0, fade_out: false, queue_in: 0 }
    end

    def new_audio_state args, opts = {}
      opts        = defaults_new_audio_state.merge opts
      decay_rate  = 0
      decay_rate  = 1.fdiv(opts[:duration]) * opts[:gain] if opts[:fade_out]
      frequency   = opts[:frequency]
      sample_rate = 48000

      {
        id:               (new_id! args),
        frequency:        frequency,
        sample_rate:      48000,
        stop_at:          args.tick_count + opts[:queue_in] + opts[:duration],
        gain:             opts[:gain].to_f,
        queue_at:         Kernel.tick_count + opts[:queue_in],
        decay_rate:       decay_rate,
        pitch:            1.0,
        looping:          true,
        paused:           false
      }
    end

    def queue_audio args, opts = {}
      graph_wave args, opts[:wave], opts[:audio_state][:frequency]
      args.state.audio_queue << opts[:audio_state]
    end

    def new_id! args
      args.state.audio_id ||= 0
      args.state.audio_id  += 1
    end

    def graph_wave args, wave, frequency
      if Kernel.tick_count != args.state.graphed_at
        args.outputs.static_lines.clear
        args.outputs.static_sprites.clear
      end

      wave = wave

      r, g, b = frequency.to_i % 85,
                frequency.to_i % 170,
                frequency.to_i % 255

      starting_rect = args.layout.rect(row: 5, col: 13)
      x_scale    = 10
      y_scale    = 100
      max_points = 25

      points = wave
      if wave.length > max_points
        resolution = wave.length.idiv max_points
        points = wave.find_all.with_index { |y, i| (i % resolution == 0) }
      end

      args.outputs.static_lines << points.map_with_index do |y, x|
        next_y = points[x + 1]

        if next_y
          {
            x:  starting_rect.x + (x * x_scale),
            y:  starting_rect.y + starting_rect.h.half + y_scale * y,
            x2: starting_rect.x + ((x + 1) * x_scale),
            y2: starting_rect.y + starting_rect.h.half + y_scale * next_y,
            r:  r,
            g:  g,
            b:  b
          }
        end
      end

      args.outputs.static_sprites << points.map_with_index do |y, x|
        {
          x:  (starting_rect.x + (x * x_scale)) - 2,
          y:  (starting_rect.y + starting_rect.h.half + y_scale * y) - 2,
          w:  4,
          h:  4,
          path: 'sprites/square-white.png',
          r: r,
          g: g,
          b: b
        }
      end

      args.state.graphed_at = Kernel.tick_count
    end
  end

  begin # region: musical note mapping
    def defaults_frequency_for
      { note: :a, octave: 5, sharp:  false, flat:   false }
    end

    def frequency_for opts = {}
      opts = defaults_frequency_for.merge opts
      octave_offset_multiplier  = opts[:octave] - 5
      note = note_frequencies_octave_5[opts[:note]]
      if octave_offset_multiplier < 0
        note = note * 1 / (octave_offset_multiplier.abs + 1)
      elsif octave_offset_multiplier > 0
        note = note * (octave_offset_multiplier.abs + 1) / 1
      end
      note
    end

    def note_frequencies_octave_5
      {
        a: 440.0,
        a_sharp: 466.16, b_flat: 466.16,
        b: 493.88,
        c: 523.25,
        c_sharp: 554.37, d_flat: 587.33,
        d: 587.33,
        d_sharp: 622.25, e_flat: 659.25,
        e: 659.25,
        f: 698.25,
        f_sharp: 739.99, g_flat: 739.99,
        g: 783.99,
        g_sharp: 830.61, a_flat: 830.61
      }
    end
  end
end

$gtk.reset

Rhythm Game Calibration - main.rb link

# ./samples/07_advanced_audio/03_rhythm_game_calibration/app/main.rb
def tick args
  defaults args
  tick_audio args
  tick_calibration args

  if args.state.tick_count > args.state.start_playing_on_tick
    args.state.beat_accumulator += args.state.beats_per_tick
    args.state.quarter_beat = args.state.beat_accumulator.to_i
    args.state.previous_quarter_beat ||= args.state.quarter_beat
  end

  if args.state.previous_quarter_beat != args.state.quarter_beat
    args.state.previous_quarter_beat_at = args.state.quarter_beat
    args.state.quarter_beat_occurred_at = args.state.tick_count
  end

  if (Kernel.tick_count - args.state.quarter_beat_occurred_at + args.state.calibration_ticks).abs == 0
    args.state.fx_queue << { x: 640,
                             y: 360,
                             w: 100,
                             h: 100,
                             r: 255,
                             anchor_x: 0.5,
                             anchor_y: 0.5,
                             g: 0,
                             b: 0,
                             a: 255,
                             path: :solid }

    args.state.fx_queue << { x: 640,
                             y: 360,
                             w: 100,
                             h: 100,
                             r: 255,
                             anchor_x: 0.5,
                             anchor_y: 0.5,
                             g: 0,
                             b: 0,
                             a: 255,
                             d_size: 20,
                             path: :solid }
  end

  if args.inputs.keyboard.key_down.space || args.inputs.controller_one.key_down.a
    input_diff = (Kernel.tick_count - args.state.quarter_beat_occurred_at + args.state.calibration_ticks)
    if input_diff.abs <= 1
      args.state.label_fx_queue << { x: 640,
                                     y: 360,
                                     anchor_x: 0.5,
                                     anchor_y: 0.5,
                                     text: "perfect! (#{input_diff})" }
    elsif input_diff.abs <= 3
      args.state.label_fx_queue << { x: 640,
                                     y: 360,
                                     anchor_x: 0.5,
                                     anchor_y: 0.5,
                                     text: "great! (#{input_diff})" }
    elsif input_diff.abs <= 5
      args.state.label_fx_queue << { x: 640,
                                     y: 360,
                                     anchor_x: 0.5,
                                     anchor_y: 0.5,
                                     text: "okay... (#{input_diff})" }
    else
      args.state.label_fx_queue << { x: 640,
                                     y: 360,
                                     anchor_x: 0.5,
                                     anchor_y: 0.5,
                                     text: "bad :-( (#{input_diff})" }
    end
  end

  calc_fx_queues args
  render args
end

def defaults args
  args.state.track_length_in_ticks     ||= 2057
  args.state.main_track                ||= :track_1
  args.state.other_track               ||= :track_2
  args.state.fx_queue                  ||= []
  args.state.label_fx_queue            ||= []
  args.state.play_head                 ||= 0
  args.state.start_playing_on_tick     ||= 180
  args.state.beats_per_minute          ||= 140
  args.state.beats_per_second          ||= args.state.beats_per_minute / 60.0
  args.state.beats_per_tick            ||= args.state.beats_per_second / 60.0
  args.state.beat_accumulator          ||= 0
  args.state.quarter_beat              ||= 0
  args.state.calibration_ticks         ||= 0
  args.state.quarter_beat_interval     ||= 1.fdiv(args.state.beats_per_tick).to_i
  args.state.quarter_beat_inputs       ||= 0
  args.state.quarter_beat_diff_history ||= []
end

def tick_audio args
  return if args.state.tick_count < args.state.start_playing_on_tick

  # start up audio
  args.audio[:track_1] ||= {
    input: "sounds/music.ogg",
    gain: 1.0,
    looping: false
  }

  args.audio[:track_2] ||= {
    input: "sounds/music.ogg",
    looping: false,
    gain: 0.0
  }

  # play head increment every tick
  args.state.play_head += 1
  args.state.play_head = args.state.play_head % args.state.track_length_in_ticks

  # every 10 seconds, cross fade
  if args.state.play_head.zmod?(600) && args.state.tick_count > args.state.start_playing_on_tick
    if args.state.main_track == :track_1
      args.state.main_track = :track_2
      args.state.other_track = :track_1
    else
      args.state.main_track = :track_1
      args.state.other_track = :track_2
    end

    if args.audio[args.state.main_track]
      args.audio[args.state.main_track].playtime = args.state.play_head.idiv(60)
    end
  end

  # perform cross fade
  if args.audio[args.state.main_track]
    args.audio[args.state.main_track].gain += 0.1
    args.audio[args.state.main_track].gain = 1.0 if args.audio[args.state.main_track].gain > 1.0
  end

  if args.audio[args.state.other_track]
    args.audio[args.state.other_track].gain -= 0.1
    args.audio[args.state.other_track].gain = 0.0 if args.audio[args.state.other_track].gain < 0.0
  end
end

def tick_calibration args
  if args.inputs.keyboard.key_down.up || args.inputs.controller_one.key_down.up
    args.state.calibration_ticks += 1
  elsif args.inputs.keyboard.key_down.down || args.inputs.controller_one.key_down.down
    args.state.calibration_ticks -= 1
  end

  if args.inputs.keyboard.key_down.m || args.inputs.controller_one.key_down.b
    args.state.player_beat_at = Kernel.tick_count
  else
    args.state.player_beat_at = nil
  end

  if args.state.player_beat_at && args.state.quarter_beat_occurred_at
    diff = args.state.player_beat_at - args.state.quarter_beat_occurred_at
    description = if (diff + args.state.calibration_ticks) < 0
                    "early: increase calibration value"
                  elsif (diff + args.state.calibration_ticks) > 0
                    "late:  decrease calibration value"
                  else
                    "perfect"
                  end

    quarter_beat_diff = { diff: (diff + args.state.calibration_ticks), description: description }
    args.state.quarter_beat_diff_history.unshift quarter_beat_diff.copy
    if args.state.quarter_beat_diff_history.length > 20
      args.state.quarter_beat_diff_history = args.state.quarter_beat_diff_history.take 20
    end
  end
end

def calc_fx_queues args
  args.state.fx_queue.each do |fx|
    fx.at ||= args.state.tick_count
    fx.d_size ||= 0
    fx.w += fx.d_size
    fx.h += fx.d_size
  end

  args.state.fx_queue.reject! { |fx| fx.at.elapsed_time > 5 }

  args.state.label_fx_queue.each do |fx|
    fx.at ||= args.state.tick_count
    fx.a  ||= 255
    fx.y    = fx.y.lerp(540, 0.1)
    fx.a   -= 5
  end

  args.state.label_fx_queue.reject! { |fx| fx.a <= 0 }
end

def render args
  if args.state.tick_count < args.state.start_playing_on_tick
    args.outputs.labels << { x: 640,
                             y: 360,
                             text: "Count down: #{(args.state.start_playing_on_tick - args.state.tick_count).idiv(60) + 1}",
                             anchor_x: 0.5,
                             anchor_y: 0.5 }
  end

  args.outputs.borders << { x: 640, y: 360, w: 100, h: 100,
                            anchor_x: 0.5, anchor_y: 0.5,
                            r: 255, g: 0, b: 0, a: 255 }

  args.outputs.primitives << args.state.fx_queue
  args.outputs.primitives << args.state.label_fx_queue
  args.state.previous_quarter_beat = args.state.quarter_beat

  args.outputs.debug.watch "Instructions: Close your eyes and listen to the beat and press 'M' (or 'B' on your controller) when you hear a quarter beat."
  args.outputs.debug.watch "              Press 'UP' or 'DOWN' to adjust calibration_ticks."
  args.outputs.debug.watch "              Press 'SPACE' (or 'A' on your controller) on quarter beats to test calibration."

  if args.audio[:track_1] && args.audio[:track_2]
    args.outputs.debug.watch "track_1 gain: #{args.audio[:track_1].gain.to_sf}"
    args.outputs.debug.watch "track_2 gain: #{args.audio[:track_2].gain.to_sf}"
  end

  args.outputs.debug.watch "beat accumulator: #{args.state.beat_accumulator.to_sf}"
  args.outputs.debug.watch "quarter beat: #{args.state.quarter_beat}"
  args.outputs.debug.watch "calibration_ticks: #{args.state.calibration_ticks.to_i}"
  args.state.quarter_beat_diff_history.each do |item|
    if item.diff >= 0
      args.outputs.debug.watch "+#{item.diff.to_sf} #{item.description}"
    elsif item.diff < 0
      args.outputs.debug.watch "#{item.diff.to_sf} #{item.description}"
    end
  end
end

Advanced Rendering link

Render Targets Clip Area - main.rb link

# ./samples/07_advanced_rendering/01_render_targets_clip_area/app/main.rb
def tick args
  # define your state
  args.state.player ||= { x: 0, y: 0, w: 300, h: 300, path: "sprites/square/blue.png" }

  # controller input for player
  args.state.player.x += args.inputs.left_right * 5
  args.state.player.y += args.inputs.up_down * 5

  # create a render target that holds the
  # full view that you want to render

  # make the background transparent
  args.outputs[:clipped_area].background_color = [0, 0, 0, 0]

  # set the w/h to match the screen
  args.outputs[:clipped_area].w = 1280
  args.outputs[:clipped_area].h = 720

  # render the player in the render target
  args.outputs[:clipped_area].sprites << args.state.player

  # render the player and clip area as borders to
  # keep track of where everything is at regardless of clip mode
  args.outputs.borders << args.state.player
  args.outputs.borders << { x: 540, y: 460, w: 200, h: 200 }

  # render the render target, but only the clipped area
  args.outputs.sprites << {
    # where to render the render target
    x: 540,
    y: 460,
    w: 200,
    h: 200,
    # what part of the render target to render
    source_x: 540,
    source_y: 460,
    source_w: 200,
    source_h: 200,
    # path of render target to render
    path: :clipped_area
  }

  # mini map
  args.outputs.borders << { x: 1280 - 160, y: 0, w: 160, h: 90 }
  args.outputs.sprites << { x: 1280 - 160, y: 0, w: 160, h: 90, path: :clipped_area }
end

$gtk.reset

Render Targets Combining Sprites - main.rb link

# ./samples/07_advanced_rendering/01_render_targets_combining_sprites/app/main.rb
# sample app shows how to use a render target to
# create a combined sprite
def tick args
  create_combined_sprite args

  # render the combined sprite
  # using its name :two_squares
  # have it move across the screen and rotate
  args.outputs.sprites << { x: Kernel.tick_count % 1280,
                            y: 0,
                            w: 80,
                            h: 80,
                            angle: Kernel.tick_count,
                            path: :two_squares }
end

def create_combined_sprite args
  # NOTE: you can have the construction of the combined
  #       sprite to happen every tick or only once (if the
  #       combined sprite never changes).
  #
  # if the combined sprite never changes, comment out the line
  # below to only construct it on the first frame and then
  # use the cached texture
  # return if Kernel.tick_count != 0 # <---- guard clause to only construct on first frame and cache

  # define the dimensions of the combined sprite
  # the name of the combined sprite is :two_squares
  args.outputs[:two_squares].w = 80
  args.outputs[:two_squares].h = 80

  # put a blue sprite within the combined sprite
  # who's width is "thin"
  args.outputs[:two_squares].sprites << {
    x: 40 - 10,
    y: 0,
    w: 20,
    h: 80,
    path: 'sprites/square/blue.png'
  }

  # put a red sprite within the combined sprite
  # who's height is "thin"
  args.outputs[:two_squares].sprites << {
    x: 0,
    y: 40 - 10,
    w: 80,
    h: 20,
    path: 'sprites/square/red.png'
  }
end

Simple Render Targets - main.rb link

# ./samples/07_advanced_rendering/01_simple_render_targets/app/main.rb
def tick args
  # args.outputs.render_targets are really really powerful.
  # They essentially allow you to create a sprite programmatically and cache the result.

  # Create a render_target of a :block and a :gradient on tick zero.
  if Kernel.tick_count == 0
    args.render_target(:block).solids << [0, 0, 1280, 100]

    # The gradient is actually just a collection of black solids with increasing
    # opacities.
    args.render_target(:gradient).solids << 90.map_with_index do |x|
      50.map_with_index do |y|
        [x * 15, y * 15, 15, 15, 0, 0, 0, (x * 3).fdiv(255) * 255]
      end
    end
  end

  # Take the :block render_target and present it horizontally centered.
  # Use a subsection of the render_targetd specified by source_x,
  # source_y, source_w, source_h.
  args.outputs.sprites << { x: 0,
                            y: 310,
                            w: 1280,
                            h: 100,
                            path: :block,
                            source_x: 0,
                            source_y: 0,
                            source_w: 1280,
                            source_h: 100 }

  # After rendering :block, render gradient on top of :block.
  args.outputs.sprites << [0, 0, 1280, 720, :gradient]

  args.outputs.labels  << [1270, 710, args.gtk.current_framerate, 0, 2, 255, 255, 255]
  tick_instructions args, "Sample app shows how to use render_targets (programmatically create cached sprites)."
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

$gtk.reset

Coordinate Systems And Render Targets - main.rb link

# ./samples/07_advanced_rendering/02_coordinate_systems_and_render_targets/app/main.rb
def tick args
  # every 4.5 seconds, swap between origin_bottom_left and origin_center
  args.state.origin_state ||= :bottom_left

  if Kernel.tick_count.zmod? 270
    args.state.origin_state = if args.state.origin_state == :bottom_left
                                :center
                              else
                                :bottom_left
                              end
  end

  if args.state.origin_state == :bottom_left
    tick_origin_bottom_left args
  else
    tick_origin_center args
  end
end

def tick_origin_center args
  # set the coordinate system to origin_center
  args.grid.origin_center!
  args.outputs.labels <<  { x: 0, y: 100, text: "args.grid.origin_center! with sprite inside of a render target, centered at 0, 0", vertical_alignment_enum: 1, alignment_enum: 1 }

  # create a render target with a sprint in the center assuming the origin is center screen
  args.outputs[:scene].sprites << { x: -50, y: -50, w: 100, h: 100, path: 'sprites/square/blue.png' }
  args.outputs.sprites << { x: -640, y: -360, w: 1280, h: 720, path: :scene }
end

def tick_origin_bottom_left args
  args.grid.origin_bottom_left!
  args.outputs.labels <<  { x: 640, y: 360 + 100, text: "args.grid.origin_bottom_left! with sprite inside of a render target, centered at 640, 360", vertical_alignment_enum: 1, alignment_enum: 1 }

  # create a render target with a sprint in the center assuming the origin is bottom left
  args.outputs[:scene].sprites << { x: 640 - 50, y: 360 - 50, w: 100, h: 100, path: 'sprites/square/blue.png' }
  args.outputs.sprites << { x: 0, y: 0, w: 1280, h: 720, path: :scene }
end

Render Targets Repeating Texture - main.rb link

# ./samples/07_advanced_rendering/02_render_targets_repeating_texture/app/main.rb
# Sample app shows how to leverage render targets to create a repeating
# texture given a source sprite.
def tick args
  args.outputs.sprites << repeating_texture(args,
                                            x: 640,
                                            y: 360,
                                            w: 1280,
                                            h: 720,
                                            anchor_x: 0.5,
                                            anchor_y: 0.5,
                                            path: 'sprites/square/blue.png')
end

def repeating_texture args, x:, y:, w:, h:, path:, anchor_x: 0, anchor_y: 0
  # create an area to store state for function
  args.state.repeating_texture_lookup ||= {}

  # create a unique name for the repeating texture
  rt_name = "#{path.hash}-#{w}-#{h}"

  # if the repeating texture has not been created yet, create it
  if args.state.repeating_texture_lookup[rt_name]
    return { x: x,
             y: y,
             w: w,
             h: h,
             anchor_x: anchor_x,
             anchor_y: anchor_y,
             path: rt_name }
  end

  # create a render target to store the repeating texture
  args.outputs[rt_name].w = w
  args.outputs[rt_name].h = h

  # calculate the sprite box for the repeating texture
  sprite_w, sprite_h = args.gtk.calcspritebox path

  # calculate the number of rows and columns needed to fill the repeating texture
  rows = h.idiv(sprite_h) + 1
  cols = w.idiv(sprite_w) + 1

  # generate the repeating texture using a render target
  # this only needs to be done once and will be cached
  args.outputs[rt_name].sprites << rows.map do |r|
                                     cols.map do |c|
                                       { x: sprite_w * c,
                                         y:  h - sprite_h * (r + 1),
                                         w: sprite_w,
                                         h: sprite_h,
                                         path: path }
                                     end
                                   end

  # store a flag in state denoting that the repeating
  # texture has been generated
  args.state.repeating_texture_lookup[rt_name] = true

  # return the repeating texture
  repeating_texture args, x: x, y: y, w: w, h: h, path: path
end

$gtk.reset

Render Targets Thick Lines - main.rb link

# ./samples/07_advanced_rendering/02_render_targets_thick_lines/app/main.rb
# Sample app shows how you can use render targets to create arbitrary shapes like a thicker line
def tick args
  args.state.line_cache ||= {}
  args.outputs.primitives << thick_line(args,
                                        args.state.line_cache,
                                        x: 0, y: 0, x2: 640, y2: 360, thickness: 3).merge(r: 0, g: 0, b: 0)
end

def thick_line args, cache, line
  line_length = Math.sqrt((line.x2 - line.x)**2 + (line.y2 - line.y)**2)
  name = "line-sprite-#{line_length}-#{line.thickness}"
  cached_line = cache[name]
  line_angle = Math.atan2(line.y2 - line.y, line.x2 - line.x) * 180 / Math::PI
  if cached_line
    perpendicular_angle = (line_angle + 90) % 360
    return cached_line.sprite.merge(x: line.x - perpendicular_angle.vector_x * (line.thickness / 2),
                                    y: line.y - perpendicular_angle.vector_y * (line.thickness / 2),
                                    angle: line_angle)
  end

  cache[name] = {
    line: line,
    thickness: line.thickness,
    sprite: {
      w: line_length,
      h: line.thickness,
      path: name,
      angle_anchor_x: 0,
      angle_anchor_y: 0
    }
  }

  args.outputs[name].w = line_length
  args.outputs[name].h = line.thickness
  args.outputs[name].solids << { x: 0, y: 0, w: line_length, h: line.thickness, r: 255, g: 255, b: 255 }
  return thick_line args, cache, line
end

Render Targets With Tile Manipulation - main.rb link

# ./samples/07_advanced_rendering/02_render_targets_with_tile_manipulation/app/main.rb
# This sample is meant to show you how to do that dripping transition thing
#  at the start of the original Doom. Most of this file is here to animate
#  a scene to wipe away; the actual wipe effect is in the last 20 lines or
#  so.

$gtk.reset   # reset all game state if reloaded.

def circle_of_blocks pass, xoffset, yoffset, angleoffset, blocksize, distance
  numblocks = 10

  for i in 1..numblocks do
    angle = ((360 / numblocks) * i) + angleoffset
    radians = angle * (Math::PI / 180)
    x = (xoffset + (distance * Math.cos(radians))).round
    y = (yoffset + (distance * Math.sin(radians))).round
    pass.solids << [ x, y, blocksize, blocksize, 255, 255, 0 ]
  end
end

def draw_scene args, pass
  pass.solids << [0, 360, 1280, 360, 0, 0, 200]
  pass.solids << [0, 0, 1280, 360, 0, 127, 0]

  blocksize = 100
  angleoffset = Kernel.tick_count * 2.5
  centerx = (1280 - blocksize) / 2
  centery = (720 - blocksize) / 2

  circle_of_blocks pass, centerx, centery, angleoffset, blocksize * 2, 500
  circle_of_blocks pass, centerx, centery, angleoffset, blocksize, 325
  circle_of_blocks pass, centerx, centery, angleoffset, blocksize / 2, 200
  circle_of_blocks pass, centerx, centery, angleoffset, blocksize / 4, 100
end

def tick args
  segments = 160

  # On the first tick, initialize some stuff.
  if !args.state.yoffsets
    args.state.baseyoff = 0
    args.state.yoffsets = []
    for i in 0..segments do
      args.state.yoffsets << rand * 100
    end
  end

  # Just draw some random stuff for a few seconds.
  args.state.static_debounce ||= 60 * 2.5
  if args.state.static_debounce > 0
    last_frame = args.state.static_debounce == 1
    target = last_frame ? args.render_target(:last_frame) : args.outputs
    draw_scene args, target
    args.state.static_debounce -= 1
    return unless last_frame
  end

  # build up the wipe...

  # this is the thing we're wiping to.
  args.outputs.sprites << [ 0, 0, 1280, 720, 'dragonruby.png' ]

  return if (args.state.baseyoff > (1280 + 100))  # stop when done sliding

  segmentw = 1280 / segments

  x = 0
  for i in 0..segments do
    yoffset = 0
    if args.state.yoffsets[i] < args.state.baseyoff
      yoffset = args.state.baseyoff - args.state.yoffsets[i]
    end

    # (720 - yoffset) flips the coordinate system, (- 720) adjusts for the height of the segment.
    args.outputs.sprites << [ x, (720 - yoffset) - 720, segmentw, 720, 'last_frame', 0, 255, 255, 255, 255, x, 0, segmentw, 720 ]
    x += segmentw
  end

  args.state.baseyoff += 4

  tick_instructions args, "Sample app shows an advanced usage of render_target."
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Render Target Viewports - main.rb link

# ./samples/07_advanced_rendering/03_render_target_viewports/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - args.state.new_entity: Used when we want to create a new object, like a sprite or button.
   For example, if we want to create a new button, we would declare it as a new entity and
   then define its properties. (Remember, you can use state to define ANY property and it will
   be retained across frames.)

   If you have a solar system and you're creating args.state.sun and setting its image path to an
   image in the sprites folder, you would do the following:
   (See samples/99_sample_nddnug_workshop for more details.)

   args.state.sun ||= args.state.new_entity(:sun) do |s|
   s.path = 'sprites/sun.png'
   end

 - String interpolation: Uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

   For example, if we have a variable
   name = "Ruby"
   then the line
   puts "How are you, #{name}?"
   would print "How are you, Ruby?" to the console.
   (Remember, string interpolation only works with double quotes!)

 - Ternary operator (?): Similar to if statement; first evalulates whether a statement is
   true or false, and then executes a command depending on that result.
   For example, if we had a variable
   grade = 75
   and used the ternary operator in the command
   pass_or_fail = grade > 65 ? "pass" : "fail"
   then the value of pass_or_fail would be "pass" since grade's value was greater than 65.

 Reminders:

 - args.grid.(left|right|top|bottom): Pixel value for the boundaries of the virtual
   720 p screen (Dragon Ruby Game Toolkits's virtual resolution is always 1280x720).

 - Numeric#shift_(left|right|up|down): Shifts the Numeric in the correct direction
   by adding or subracting.

 - ARRAY#inside_rect?: An array with at least two values is considered a point. An array
   with at least four values is considered a rect. The inside_rect? function returns true
   or false depending on if the point is inside the rect.

 - ARRAY#intersect_rect?: Returns true or false depending on if the two rectangles intersect.

 - args.inputs.mouse.click: This property will be set if the mouse was clicked.
   For more information about the mouse, go to mygame/documentation/07-mouse.md.

 - args.inputs.keyboard.key_up.KEY: The value of the properties will be set
   to the frame  that the key_up event occurred (the frame correlates
   to Kernel.tick_count).
   For more information about the keyboard, go to mygame/documentation/06-keyboard.md.

 - args.state.labels:
   The parameters for a label are
   1. the position (x, y)
   2. the text
   3. the size
   4. the alignment
   5. the color (red, green, and blue saturations)
   6. the alpha (or transparency)
   For more information about labels, go to mygame/documentation/02-labels.md.

 - args.state.lines:
   The parameters for a line are
   1. the starting position (x, y)
   2. the ending position (x2, y2)
   3. the color (red, green, and blue saturations)
   4. the alpha (or transparency)
   For more information about lines, go to mygame/documentation/04-lines.md.

 - args.state.solids (and args.state.borders):
   The parameters for a solid (or border) are
   1. the position (x, y)
   2. the width (w)
   3. the height (h)
   4. the color (r, g, b)
   5. the alpha (or transparency)
   For more information about solids and borders, go to mygame/documentation/03-solids-and-borders.md.

 - args.state.sprites:
   The parameters for a sprite are
   1. the position (x, y)
   2. the width (w)
   3. the height (h)
   4. the image path
   5. the angle
   6. the alpha (or transparency)
   For more information about sprites, go to mygame/documentation/05-sprites.md.
=end

# This sample app shows different objects that can be used when making games, such as labels,
# lines, sprites, solids, buttons, etc. Each demo section shows how these objects can be used.

# Also note that Kernel.tick_count refers to the passage of time, or current frame.

class TechDemo
  attr_accessor :inputs, :state, :outputs, :grid, :args

  # Calls all methods necessary for the app to run properly.
  def tick
    labels_tech_demo
    lines_tech_demo
    solids_tech_demo
    borders_tech_demo
    sprites_tech_demo
    keyboards_tech_demo
    controller_tech_demo
    mouse_tech_demo
    point_to_rect_tech_demo
    rect_to_rect_tech_demo
    button_tech_demo
    export_game_state_demo
    window_state_demo
    render_seperators
  end

  # Shows output of different kinds of labels on the screen
  def labels_tech_demo
    outputs.labels << [grid.left.shift_right(5), grid.top.shift_down(5), "This is a label located at the top left."]
    outputs.labels << [grid.left.shift_right(5), grid.bottom.shift_up(30), "This is a label located at the bottom left."]
    outputs.labels << [ 5, 690, "Labels (x, y, text, size, align, r, g, b, a)"]
    outputs.labels << [ 5, 660, "Smaller label.",  -2]
    outputs.labels << [ 5, 630, "Small label.",    -1]
    outputs.labels << [ 5, 600, "Medium label.",    0]
    outputs.labels << [ 5, 570, "Large label.",     1]
    outputs.labels << [ 5, 540, "Larger label.",    2]
    outputs.labels << [300, 660, "Left aligned.",    0, 2]
    outputs.labels << [300, 640, "Center aligned.",  0, 1]
    outputs.labels << [300, 620, "Right aligned.",   0, 0]
    outputs.labels << [175, 595, "Red Label.",       0, 0, 255,   0,   0]
    outputs.labels << [175, 575, "Green Label.",     0, 0,   0, 255,   0]
    outputs.labels << [175, 555, "Blue Label.",      0, 0,   0,   0, 255]
    outputs.labels << [175, 535, "Faded Label.",     0, 0,   0,   0,   0, 128]
  end

  # Shows output of lines on the screen
  def lines_tech_demo
    outputs.labels << [5, 500, "Lines (x, y, x2, y2, r, g, b, a)"]
    outputs.lines  << [5, 450, 100, 450]
    outputs.lines  << [5, 430, 300, 430]
    outputs.lines  << [5, 410, 300, 410, Kernel.tick_count % 255, 0, 0, 255] # red saturation changes
    outputs.lines  << [5, 390 - Kernel.tick_count % 25, 300, 390, 0, 0, 0, 255] # y position changes
    outputs.lines  << [5 + Kernel.tick_count % 200, 360, 300, 360, 0, 0, 0, 255] # x position changes
  end

  # Shows output of different kinds of solids on the screen
  def solids_tech_demo
    outputs.labels << [  5, 350, "Solids (x, y, w, h, r, g, b, a)"]
    outputs.solids << [ 10, 270, 50, 50]
    outputs.solids << [ 70, 270, 50, 50, 0, 0, 0]
    outputs.solids << [130, 270, 50, 50, 255, 0, 0]
    outputs.solids << [190, 270, 50, 50, 255, 0, 0, 128]
    outputs.solids << [250, 270, 50, 50, 0, 0, 0, 128 + Kernel.tick_count % 128] # transparency changes
  end

  # Shows output of different kinds of borders on the screen
  # The parameters for a border are the same as the parameters for a solid
  def borders_tech_demo
    outputs.labels <<  [  5, 260, "Borders (x, y, w, h, r, g, b, a)"]
    outputs.borders << [ 10, 180, 50, 50]
    outputs.borders << [ 70, 180, 50, 50, 0, 0, 0]
    outputs.borders << [130, 180, 50, 50, 255, 0, 0]
    outputs.borders << [190, 180, 50, 50, 255, 0, 0, 128]
    outputs.borders << [250, 180, 50, 50, 0, 0, 0, 128 + Kernel.tick_count % 128] # transparency changes
  end

  # Shows output of different kinds of sprites on the screen
  def sprites_tech_demo
    outputs.labels <<  [   5, 170, "Sprites (x, y, w, h, path, angle, a)"]
    outputs.sprites << [  10, 40, 128, 101, 'dragonruby.png']
    outputs.sprites << [ 150, 40, 128, 101, 'dragonruby.png', Kernel.tick_count % 360] # angle changes
    outputs.sprites << [ 300, 40, 128, 101, 'dragonruby.png', 0, Kernel.tick_count % 255] # transparency changes
  end

  # Holds size, alignment, color (black), and alpha (transparency) parameters
  # Using small_font as a parameter accounts for all remaining parameters
  # so they don't have to be repeatedly typed
  def small_font
    [-2, 0, 0, 0, 0, 255]
  end

  # Sets position of each row
  # Converts given row value to pixels that DragonRuby understands
  def row_to_px row_number

    # Row 0 starts 5 units below the top of the grid.
    # Each row afterward is 20 units lower.
    grid.top.shift_down(5).shift_down(20 * row_number)
  end

  # Uses labels to output current game time (passage of time), and whether or not "h" was pressed
  # If "h" is pressed, the frame is output when the key_up event occurred
  def keyboards_tech_demo
    outputs.labels << [460, row_to_px(0), "Current game time: #{Kernel.tick_count}", small_font]
    outputs.labels << [460, row_to_px(2), "Keyboard input: inputs.keyboard.key_up.h", small_font]
    outputs.labels << [460, row_to_px(3), "Press \"h\" on the keyboard.", small_font]

    if inputs.keyboard.key_up.h # if "h" key_up event occurs
      state.h_pressed_at = Kernel.tick_count # frame it occurred is stored
    end

    # h_pressed_at is initially set to false, and changes once the user presses the "h" key.
    state.h_pressed_at ||= false

    if state.h_pressed_at # if h is pressed (pressed_at has a frame number and is no longer false)
      outputs.labels << [460, row_to_px(4), "\"h\" was pressed at time: #{state.h_pressed_at}", small_font]
    else # otherwise, label says "h" was never pressed
      outputs.labels << [460, row_to_px(4), "\"h\" has never been pressed.", small_font]
    end

    # border around keyboard input demo section
    outputs.borders << [455, row_to_px(5), 360, row_to_px(2).shift_up(5) - row_to_px(5)]
  end

  # Sets definition for a small label
  # Makes it easier to position labels in respect to the position of other labels
  def small_label x, row, message
    [x, row_to_px(row), message, small_font]
  end

  # Uses small labels to show whether the "a" button on the controller is down, held, or up.
  # y value of each small label is set by calling the row_to_px method
  def controller_tech_demo
    x = 460
    outputs.labels << small_label(x, 6, "Controller one input: inputs.controller_one")
    outputs.labels << small_label(x, 7, "Current state of the \"a\" button.")
    outputs.labels << small_label(x, 8, "Check console window for more info.")

    if inputs.controller_one.key_down.a # if "a" is in "down" state
      outputs.labels << small_label(x, 9, "\"a\" button down: #{inputs.controller_one.key_down.a}")
      puts "\"a\" button down at #{inputs.controller_one.key_down.a}" # prints frame the event occurred
    elsif inputs.controller_one.key_held.a # if "a" is held down
      outputs.labels << small_label(x, 9, "\"a\" button held: #{inputs.controller_one.key_held.a}")
    elsif inputs.controller_one.key_up.a # if "a" is in up state
      outputs.labels << small_label(x, 9, "\"a\" button up: #{inputs.controller_one.key_up.a}")
      puts "\"a\" key up at #{inputs.controller_one.key_up.a}"
    else # if no event has occurred
      outputs.labels << small_label(x, 9, "\"a\" button state is nil.")
    end

    # border around controller input demo section
    outputs.borders << [455, row_to_px(10), 360, row_to_px(6).shift_up(5) - row_to_px(10)]
  end

  # Outputs when the mouse was clicked, as well as the coordinates on the screen
  # of where the click occurred
  def mouse_tech_demo
    x = 460

    outputs.labels << small_label(x, 11, "Mouse input: inputs.mouse")

    if inputs.mouse.click # if click has a value and is not nil
      state.last_mouse_click = inputs.mouse.click # coordinates of click are stored
    end

    if state.last_mouse_click # if mouse is clicked (has coordinates as value)
      # outputs the time (frame) the click occurred, as well as how many frames have passed since the event
      outputs.labels << small_label(x, 12, "Mouse click happened at: #{state.last_mouse_click.created_at}, #{state.last_mouse_click.created_at_elapsed}")
      # outputs coordinates of click
      outputs.labels << small_label(x, 13, "Mouse click location: #{state.last_mouse_click.point.x}, #{state.last_mouse_click.point.y}")
    else # otherwise if the mouse has not been clicked
      outputs.labels << small_label(x, 12, "Mouse click has not occurred yet.")
      outputs.labels << small_label(x, 13, "Please click mouse.")
    end
  end

  # Outputs whether a mouse click occurred inside or outside of a box
  def point_to_rect_tech_demo
    x = 460

    outputs.labels << small_label(x, 15, "Click inside the blue box maybe ---->")

    box = [765, 370, 50, 50, 0, 0, 170] # blue box
    outputs.borders << box

    if state.last_mouse_click # if the mouse was clicked
      if state.last_mouse_click.point.inside_rect? box # if mouse clicked inside box
        outputs.labels << small_label(x, 16, "Mouse click happened inside the box.")
      else # otherwise, if mouse was clicked outside the box
        outputs.labels << small_label(x, 16, "Mouse click happened outside the box.")
      end
    else # otherwise, if was not clicked at all
      outputs.labels << small_label(x, 16, "Mouse click has not occurred yet.") # output if the mouse was not clicked
    end

    # border around mouse input demo section
    outputs.borders << [455, row_to_px(14), 360, row_to_px(11).shift_up(5) - row_to_px(14)]
  end

  # Outputs a red box onto the screen. A mouse click from the user inside of the red box will output
  # a smaller box. If two small boxes are inside of the red box, it will be determined whether or not
  # they intersect.
  def rect_to_rect_tech_demo
    x = 460

    outputs.labels << small_label(x, 17.5, "Click inside the red box below.") # label with instructions
    red_box = [460, 250, 355, 90, 170, 0, 0] # definition of the red box
    outputs.borders << red_box # output as a border (not filled in)

    # If the mouse is clicked inside the red box, two collision boxes are created.
    if inputs.mouse.click
      if inputs.mouse.click.point.inside_rect? red_box
        if !state.box_collision_one # if the collision_one box does not yet have a definition
          # Subtracts 25 from the x and y positions of the click point in order to make the click point the center of the box.
          # You can try deleting the subtraction to see how it impacts the box placement.
          state.box_collision_one = [inputs.mouse.click.point.x - 25, inputs.mouse.click.point.y - 25, 50, 50, 180, 0,   0, 180]  # sets definition
        elsif !state.box_collision_two # if collision_two does not yet have a definition
          state.box_collision_two = [inputs.mouse.click.point.x - 25, inputs.mouse.click.point.y - 25, 50, 50,   0, 0, 180, 180] # sets definition
        else
          state.box_collision_one = nil # both boxes are empty
          state.box_collision_two = nil
        end
      end
    end

    # If collision boxes exist, they are output onto screen inside the red box as solids
    if state.box_collision_one
      outputs.solids << state.box_collision_one
    end

    if state.box_collision_two
      outputs.solids << state.box_collision_two
    end

    # Outputs whether or not the two collision boxes intersect.
    if state.box_collision_one && state.box_collision_two # if both collision_boxes are defined (and not nil or empty)
      if state.box_collision_one.intersect_rect? state.box_collision_two # if the two boxes intersect
        outputs.labels << small_label(x, 23.5, 'The boxes intersect.')
      else # otherwise, if the two boxes do not intersect
        outputs.labels << small_label(x, 23.5, 'The boxes do not intersect.')
      end
    else
      outputs.labels << small_label(x, 23.5, '--') # if the two boxes are not defined (are nil or empty), this label is output
    end
  end

  # Creates a button and outputs it onto the screen using labels and borders.
  # If the button is clicked, the color changes to make it look faded.
  def button_tech_demo
    x, y, w, h = 460, 160, 300, 50
    state.button        ||= state.new_entity(:button_with_fade)

    # Adds w.half to x and h.half + 10 to y in order to display the text inside the button's borders.
    state.button.label  ||= [x + w.half, y + h.half + 10, "click me and watch me fade", 0, 1]
    state.button.border ||= [x, y, w, h]

    if inputs.mouse.click && inputs.mouse.click.point.inside_rect?(state.button.border) # if mouse is clicked, and clicked inside button's border
      state.button.clicked_at = inputs.mouse.click.created_at # stores the time the click occurred
    end

    outputs.labels << state.button.label
    outputs.borders << state.button.border

    if state.button.clicked_at # if button was clicked (variable has a value and is not nil)

      # The appearance of the button changes for 0.25 seconds after the time the button is clicked at.
      # The color changes (rgb is set to 0, 180, 80) and the transparency gradually changes.
      # Change 0.25 to 1.25 and notice that the transparency takes longer to return to normal.
      outputs.solids << [x, y, w, h, 0, 180, 80, 255 * state.button.clicked_at.ease(0.25.seconds, :flip)]
    end
  end

  # Creates a new button by declaring it as a new entity, and sets values.
  def new_button_prefab x, y, message
    w, h = 300, 50
    button        = state.new_entity(:button_with_fade)
    button.label  = [x + w.half, y + h.half + 10, message, 0, 1] # '+ 10' keeps label's text within button's borders
    button.border = [x, y, w, h] # sets border definition
    button
  end

  # If the mouse has been clicked and the click's location is inside of the button's border, that means
  # that the button has been clicked. This method returns a boolean value.
  def button_clicked? button
    inputs.mouse.click && inputs.mouse.click.point.inside_rect?(button.border)
  end

  # Determines if button was clicked, and changes its appearance if it is clicked
  def tick_button_prefab button
    outputs.labels << button.label # outputs button's label and border
    outputs.borders << button.border

    if button_clicked? button # if button is clicked
      button.clicked_at = inputs.mouse.click.created_at # stores the time that the button was clicked
    end

    if button.clicked_at # if clicked_at has a frame value and is not nil
      # button is output; color changes and transparency changes for 0.25 seconds after click occurs
      outputs.solids << [button.border.x, button.border.y, button.border.w, button.border.h,
                         0, 180, 80, 255 * button.clicked_at.ease(0.25.seconds, :flip)] # transparency changes for 0.25 seconds
    end
  end

  # Exports the app's game state if the export button is clicked.
  def export_game_state_demo
    state.export_game_state_button ||= new_button_prefab(460, 100, "click to export app state")
    tick_button_prefab(state.export_game_state_button) # calls method to output button
    if button_clicked? state.export_game_state_button # if the export button is clicked
      args.gtk.export! "Exported from clicking the export button in the tech demo." # the export occurs
    end
  end

  # The mouse and keyboard focus are set to "yes" when the Dragonruby window is the active window.
  def window_state_demo
    m = $gtk.args.inputs.mouse.has_focus ? 'Y' : 'N' # ternary operator (similar to if statement)
    k = $gtk.args.inputs.keyboard.has_focus ? 'Y' : 'N'
    outputs.labels << [460, 20, "mouse focus: #{m}   keyboard focus: #{k}", small_font]
  end

  #Sets values for the horizontal separator (divides demo sections)
  def horizontal_seperator y, x, x2
    [x, y, x2, y, 150, 150, 150]
  end

  #Sets the values for the vertical separator (divides demo sections)
  def vertical_seperator x, y, y2
    [x, y, x, y2, 150, 150, 150]
  end

  # Outputs vertical and horizontal separators onto the screen to separate each demo section.
  def render_seperators
    outputs.lines << horizontal_seperator(505, grid.left, 445)
    outputs.lines << horizontal_seperator(353, grid.left, 445)
    outputs.lines << horizontal_seperator(264, grid.left, 445)
    outputs.lines << horizontal_seperator(174, grid.left, 445)

    outputs.lines << vertical_seperator(445, grid.top, grid.bottom)

    outputs.lines << horizontal_seperator(690, 445, 820)
    outputs.lines << horizontal_seperator(426, 445, 820)

    outputs.lines << vertical_seperator(820, grid.top, grid.bottom)
  end
end

$tech_demo = TechDemo.new

def tick args
  $tech_demo.inputs = args.inputs
  $tech_demo.state = args.state
  $tech_demo.grid = args.grid
  $tech_demo.args = args
  $tech_demo.outputs = args.render_target(:mini_map)
  $tech_demo.tick
  args.outputs.labels  << [830, 715, "Render target:", [-2, 0, 0, 0, 0, 255]]
  args.outputs.sprites << [0, 0, 1280, 720, :mini_map]
  args.outputs.sprites << [830, 300, 675, 379, :mini_map]
  tick_instructions args, "Sample app shows all the rendering apis available."
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Render Primitive Hierarchies - main.rb link

# ./samples/07_advanced_rendering/04_render_primitive_hierarchies/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - Nested array: An array whose individual elements are also arrays; useful for
   storing groups of similar data.  Also called multidimensional arrays.

   In this sample app, we see nested arrays being used in object definitions.
   Notice the parameters for solids, listed below. Parameters 1-3 set the
   definition for the rect, and parameter 4 sets the definition of the color.

   Instead of having a solid definition that looks like this,
   [X, Y, W, H, R, G, B]
   we can separate it into two separate array definitions in one, like this
   [[X, Y, W, H], [R, G, B]]
   and both options work fine in defining our solid (or any object).

 - Collections: Lists of data; useful for organizing large amounts of data.
   One element of a collection could be an array (which itself contains many elements).
   For example, a collection that stores two solid objects would look like this:
   [
    [100, 100, 50, 50, 0, 0, 0],
    [100, 150, 50, 50, 255, 255, 255]
   ]
   If this collection was added to args.outputs.solids, two solids would be output
   next to each other, one black and one white.
   Nested arrays can be used in collections, as you will see in this sample app.

 Reminders:

 - args.outputs.solids: An array. The values generate a solid.
   The parameters for a solid are
   1. The position on the screen (x, y)
   2. The width (w)
   3. The height (h)
   4. The color (r, g, b) (if a color is not assigned, the object's default color will be black)
   NOTE: THE PARAMETERS ARE THE SAME FOR BORDERS!

   Here is an example of a (red) border or solid definition:
   [100, 100, 400, 500, 255, 0, 0]
   It will be a solid or border depending on if it is added to args.outputs.solids or args.outputs.borders.
   For more information about solids and borders, go to mygame/documentation/03-solids-and-borders.md.

 - args.outputs.sprites: An array. The values generate a sprite.
   The parameters for sprites are
   1. The position on the screen (x, y)
   2. The width (w)
   3. The height (h)
   4. The image path (p)

   Here is an example of a sprite definition:
   [100, 100, 400, 500, 'sprites/dragonruby.png']
   For more information about sprites, go to mygame/documentation/05-sprites.md.

=end

# This code demonstrates the creation and output of objects like sprites, borders, and solids
# If filled in, they are solids
# If hollow, they are borders
# If images, they are sprites

# Solids are added to args.outputs.solids
# Borders are added to args.outputs.borders
# Sprites are added to args.outputs.sprites

# The tick method runs 60 frames every second.
# Your game is going to happen under this one function.
def tick args
  border_as_solid_and_solid_as_border args
  sprite_as_border_or_solids args
  collection_of_borders_and_solids args
  collection_of_sprites args
end

# Shows a border being output onto the screen as a border and a solid
# Also shows how colors can be set
def border_as_solid_and_solid_as_border args
  border = [0, 0, 50, 50]
  args.outputs.borders << border
  args.outputs.solids  << border

  # Red, green, blue saturations (last three parameters) can be any number between 0 and 255
  border_with_color = [0, 100, 50, 50, 255, 0, 0]
  args.outputs.borders << border_with_color
  args.outputs.solids  << border_with_color

  border_with_nested_color = [0, 200, 50, 50, [0, 255, 0]] # nested color
  args.outputs.borders << border_with_nested_color
  args.outputs.solids  << border_with_nested_color

  border_with_nested_rect = [[0, 300, 50, 50], 0, 0, 255] # nested rect
  args.outputs.borders << border_with_nested_rect
  args.outputs.solids  << border_with_nested_rect

  border_with_nested_color_and_rect = [[0, 400, 50, 50], [255, 0, 255]] # nested rect and color
  args.outputs.borders << border_with_nested_color_and_rect
  args.outputs.solids  << border_with_nested_color_and_rect
end

# Shows a sprite output onto the screen as a sprite, border, and solid
# Demonstrates that all three outputs appear differently on screen
def sprite_as_border_or_solids args
  sprite = [100, 0, 50, 50, 'sprites/ship.png']
  args.outputs.sprites << sprite

  # Sprite_as_border variable has same parameters (excluding position) as above object,
  # but will appear differently on screen because it is added to args.outputs.borders
  sprite_as_border = [100, 100, 50, 50, 'sprites/ship.png']
  args.outputs.borders << sprite_as_border

  # Sprite_as_solid variable has same parameters (excluding position) as above object,
  # but will appear differently on screen because it is added to args.outputs.solids
  sprite_as_solid = [100, 200, 50, 50, 'sprites/ship.png']
  args.outputs.solids << sprite_as_solid
end

# Holds and outputs a collection of borders and a collection of solids
# Collections are created by using arrays to hold parameters of each individual object
def collection_of_borders_and_solids args
  collection_borders = [
    [
      [200,  0, 50, 50],                    # black border
      [200,  100, 50, 50, 255, 0, 0],       # red border
      [200,  200, 50, 50, [0, 255, 0]],     # nested color
    ],
    [[200, 300, 50, 50], 0, 0, 255],        # nested rect
    [[200, 400, 50, 50], [255, 0, 255]]     # nested rect and nested color
  ]

  args.outputs.borders << collection_borders

  collection_solids = [
    [
      [[300, 300, 50, 50], 0, 0, 255],      # nested rect
      [[300, 400, 50, 50], [255, 0, 255]]   # nested rect and nested color
    ],
    [300,  0, 50, 50],
    [300,  100, 50, 50, 255, 0, 0],
    [300,  200, 50, 50, [0, 255, 0]],       # nested color
  ]

  args.outputs.solids << collection_solids
end

# Holds and outputs a collection of sprites by adding it to args.outputs.sprites
# Also outputs a collection with same parameters (excluding position) by adding
# it to args.outputs.solids and another to args.outputs.borders
def collection_of_sprites args
  sprites_collection = [
    [
      [400, 0, 50, 50, 'sprites/ship.png'],
      [400, 100, 50, 50, 'sprites/ship.png'],
    ],
    [400, 200, 50, 50, 'sprites/ship.png']
  ]

  args.outputs.sprites << sprites_collection

  args.outputs.solids << [
    [500, 0, 50, 50, 'sprites/ship.png'],
    [500, 100, 50, 50, 'sprites/ship.png'],
    [[[500, 200, 50, 50, 'sprites/ship.png']]]
  ]

  args.outputs.borders << [
    [
      [600, 0, 50, 50, 'sprites/ship.png'],
      [600, 100, 50, 50, 'sprites/ship.png'],
    ],
    [600, 200, 50, 50, 'sprites/ship.png']
  ]
end

Render Primitives As Hash - main.rb link

# ./samples/07_advanced_rendering/05_render_primitives_as_hash/app/main.rb
=begin

 Reminders:

 - Hashes: Collection of unique keys and their corresponding values. The value can be found
   using their keys.

   For example, if we have a "numbers" hash that stores numbers in English as the
   key and numbers in Spanish as the value, we'd have a hash that looks like this...
   numbers = { "one" => "uno", "two" => "dos", "three" => "tres" }
   and on it goes.

   Now if we wanted to find the corresponding value of the "one" key, we could say
   puts numbers["one"]
   which would print "uno" to the console.

 - args.outputs.sprites: An array. The values generate a sprite.
   The parameters are [X, Y, WIDTH, HEIGHT, PATH, ANGLE, ALPHA, RED, GREEN, BLUE]
   For more information about sprites, go to mygame/documentation/05-sprites.md.

 - args.outputs.labels: An array. The values generate a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGNMENT, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.

 - args.outputs.solids: An array. The values generate a solid.
   The parameters are [X, Y, WIDTH, HEIGHT, RED, GREEN, BLUE, ALPHA]
   For more information about solids, go to mygame/documentation/03-solids-and-borders.md.

 - args.outputs.borders: An array. The values generate a border.
   The parameters are the same as a solid.
   For more information about borders, go to mygame/documentation/03-solids-and-borders.md.

 - args.outputs.lines: An array. The values generate a line.
   The parameters are [X, Y, X2, Y2, RED, GREEN, BLUE]
   For more information about labels, go to mygame/documentation/02-labels.md.

=end

# This sample app demonstrates how hashes can be used to output different kinds of objects.

def tick args
  args.state.angle ||= 0 # initializes angle to 0
  args.state.angle  += 1 # increments angle by 1 every frame (60 times a second)

  # Outputs sprite using a hash
  args.outputs.sprites << {
    x: 30,                          # sprite position
    y: 550,
    w: 128,                         # sprite size
    h: 101,
    path: "dragonruby.png",         # image path
    angle: args.state.angle,        # angle
    a: 255,                         # alpha (transparency)
    r: 255,                         # color saturation
    g: 255,
    b: 255,
    tile_x:  0,                     # sprite sub division/tile
    tile_y:  0,
    tile_w: -1,
    tile_h: -1,
    flip_vertically: false,         # don't flip sprite
    flip_horizontally: false,
    angle_anchor_x: 0.5,            # rotation center set to middle
    angle_anchor_y: 0.5
  }

  # Outputs label using a hash
  args.outputs.labels << {
    x:              200,                 # label position
    y:              550,
    text:           "dragonruby",        # label text
    size_enum:      2,
    alignment_enum: 1,
    r:              155,                 # color saturation
    g:              50,
    b:              50,
    a:              255,                 # transparency
    font:           "fonts/manaspc.ttf"  # font style; without mentioned file, label won't output correctly
  }

  # Outputs solid using a hash
  # [X, Y, WIDTH, HEIGHT, RED, GREEN, BLUE, ALPHA]
  args.outputs.solids << {
    x: 400,                         # position
    y: 550,
    w: 160,                         # size
    h:  90,
    r: 120,                         # color saturation
    g:  50,
    b:  50,
    a: 255                          # transparency
  }

  # Outputs border using a hash
  # Same parameters as a solid
  args.outputs.borders << {
    x: 600,
    y: 550,
    w: 160,
    h:  90,
    r: 120,
    g:  50,
    b:  50,
    a: 255
  }

  # Outputs line using a hash
  args.outputs.lines << {
    x:  900,                        # starting position
    y:  550,
    x2: 1200,                       # ending position
    y2: 550,
    r:  120,                        # color saturation
    g:   50,
    b:   50,
    a:  255                         # transparency
  }

  # Outputs sprite as a primitive using a hash
  args.outputs.primitives << {
    x: 30,                          # position
    y: 200,
    w: 128,                         # size
    h: 101,
    path: "dragonruby.png",         # image path
    angle: args.state.angle,        # angle
    a: 255,                         # transparency
    r: 255,                         # color saturation
    g: 255,
    b: 255,
    tile_x:  0,                     # sprite sub division/tile
    tile_y:  0,
    tile_w: -1,
    tile_h: -1,
    flip_vertically: false,         # don't flip
    flip_horizontally: false,
    angle_anchor_x: 0.5,            # rotation center set to middle
    angle_anchor_y: 0.5
  }.sprite!

  # Outputs label as primitive using a hash
  args.outputs.primitives << {
    x:         200,                 # position
    y:         200,
    text:      "dragonruby",        # text
    size:      2,
    alignment: 1,
    r:         155,                 # color saturation
    g:         50,
    b:         50,
    a:         255,                 # transparency
    font:      "fonts/manaspc.ttf"  # font style
  }.label!

  # Outputs solid as primitive using a hash
  args.outputs.primitives << {
    x: 400,                         # position
    y: 200,
    w: 160,                         # size
    h:  90,
    r: 120,                         # color saturation
    g:  50,
    b:  50,
    a: 255                          # transparency
  }.solid!

  # Outputs border as primitive using a hash
  # Same parameters as solid
  args.outputs.primitives << {
    x: 600,                         # position
    y: 200,
    w: 160,                         # size
    h:  90,
    r: 120,                         # color saturation
    g:  50,
    b:  50,
    a: 255                          # transparency
  }.border!

  # Outputs line as primitive using a hash
  args.outputs.primitives << {
    x:  900,                        # starting position
    y:  200,
    x2: 1200,                       # ending position
    y2: 200,
    r:  120,                        # color saturation
    g:   50,
    b:   50,
    a:  255                         # transparency
  }.line!
end

Buttons As Render Targets - main.rb link

# ./samples/07_advanced_rendering/06_buttons_as_render_targets/app/main.rb
def tick args
  # create a texture/render_target that's composed of a border and a label
  create_button args, :hello_world_button, "Hello World", 500, 50

  # two button primitives using the hello_world_button render_target
  args.state.buttons ||= [
    # one button at the top
    { id: :top_button, x: 640 - 250, y: 80.from_top, w: 500, h: 50, path: :hello_world_button },

    # another button at the buttom, upside down, and flipped horizontally
    { id: :bottom_button, x: 640 - 250, y: 30, w: 500, h: 50, path: :hello_world_button, angle: 180, flip_horizontally: true },
  ]

  # check if a mouse click occurred
  if args.inputs.mouse.click
    # check to see if any of the buttons were intersected
    # and set the selected button if so
    args.state.selected_button = args.state.buttons.find { |b| b.intersect_rect? args.inputs.mouse }
  end

  # render the buttons
  args.outputs.sprites << args.state.buttons

  # if there was a selected button, print it's id
  if args.state.selected_button
    args.outputs.labels << { x: 30, y: 30.from_top, text: "#{args.state.selected_button.id} was clicked." }
  end
end

def create_button args, id, text, w, h
  # render_targets only need to be created once, we use the the id to determine if the texture
  # has already been created
  args.state.created_buttons ||= {}
  return if args.state.created_buttons[id]

  # if the render_target hasn't been created, then generate it and store it in the created_buttons cache
  args.state.created_buttons[id] = { created_at: Kernel.tick_count, id: id, w: w, h: h, text: text }

  # define the w/h of the texture
  args.outputs[id].w = w
  args.outputs[id].h = h

  # create a border
  args.outputs[id].borders << { x: 0, y: 0, w: w, h: h }

  # create a label centered vertically and horizontally within the texture
  args.outputs[id].labels << { x: w / 2, y: h / 2, text: text, vertical_alignment_enum: 1, alignment_enum: 1 }
end

Pixel Arrays - main.rb link

# ./samples/07_advanced_rendering/06_pixel_arrays/app/main.rb
def tick args
  args.state.posinc ||= 1
  args.state.pos ||= 0
  args.state.rotation ||= 0

  dimension = 10  # keep it small and let the GPU scale it when rendering the sprite.

  # Set up our "scanner" pixel array and fill it with black pixels.
  args.pixel_array(:scanner).width = dimension
  args.pixel_array(:scanner).height = dimension
  args.pixel_array(:scanner).pixels.fill(0xFF000000, 0, dimension * dimension)  # black, full alpha

  # Draw a green line that bounces up and down the sprite.
  args.pixel_array(:scanner).pixels.fill(0xFF00FF00, dimension * args.state.pos, dimension)  # green, full alpha

  # Adjust position for next frame.
  args.state.pos += args.state.posinc
  if args.state.posinc > 0 && args.state.pos >= dimension
    args.state.posinc = -1
    args.state.pos = dimension - 1
  elsif args.state.posinc < 0 && args.state.pos < 0
    args.state.posinc = 1
    args.state.pos = 1
  end

  # New/changed pixel arrays get uploaded to the GPU before we render
  #  anything. At that point, they can be scaled, rotated, and otherwise
  #  used like any other sprite.
  w = 100
  h = 100
  x = (1280 - w) / 2
  y = (720 - h) / 2
  args.outputs.background_color = [64, 0, 128]
  args.outputs.primitives << [x, y, w, h, :scanner, args.state.rotation].sprite
  args.state.rotation += 1

  args.outputs.primitives << args.gtk.current_framerate_primitives
end


$gtk.reset

Pixel Arrays From File - main.rb link

# ./samples/07_advanced_rendering/06_pixel_arrays_from_file/app/main.rb
def tick args
  args.state.rotation ||= 0

  # on load, get pixels from png and load it into a pixel array
  if Kernel.tick_count == 0
    pixel_array = args.gtk.get_pixels 'sprites/square/blue.png'
    args.pixel_array(:square).w = pixel_array.w
    args.pixel_array(:square).h = pixel_array.h
    pixel_array.pixels.each_with_index do |p, i|
      args.pixel_array(:square).pixels[i] = p
    end
  end

  w = 100
  h = 100
  x = (1280 - w) / 2
  y = (720 - h) / 2
  args.outputs.background_color = [64, 0, 128]
  # render the pixel array by name
  args.outputs.primitives << { x: x, y: y, w: w, h: h, path: :square, angle: args.state.rotation }
  args.state.rotation += 1

  args.outputs.primitives << args.gtk.current_framerate_primitives
end

$gtk.reset

Shake Camera - main.rb link

# ./samples/07_advanced_rendering/07_shake_camera/app/main.rb
# Demo of camera shake
# Hold space to shake and release to stop

class ScreenShake
  attr_gtk

  def tick
    defaults
    calc_camera

    outputs.labels << { x: 600, y: 400, text: "Hold Space!" }

    # Add outputs to :scene
    outputs[:scene].sprites << { x: 100, y: 100,          w: 80, h: 80, path: 'sprites/square/blue.png' }
    outputs[:scene].sprites << { x: 200, y: 300.from_top, w: 80, h: 80, path: 'sprites/square/blue.png' }
    outputs[:scene].sprites << { x: 900, y: 200,          w: 80, h: 80, path: 'sprites/square/blue.png' }

    # Describe how to render :scene
    outputs.sprites << { x: 0 - state.camera.x_offset,
                         y: 0 - state.camera.y_offset,
                         w: 1280,
                         h: 720,
                         angle: state.camera.angle,
                         path: :scene }
  end

  def defaults
    state.camera.trauma ||= 0
    state.camera.angle ||= 0
    state.camera.x_offset ||= 0
    state.camera.y_offset ||= 0
  end

  def calc_camera
    if inputs.keyboard.key_held.space
      state.camera.trauma += 0.02
    end

    next_camera_angle = 180.0 / 20.0 * state.camera.trauma**2
    next_offset       = 100.0 * state.camera.trauma**2

    # Ensure that the camera angle always switches from
    # positive to negative and vice versa
    # which gives the effect of shaking back and forth
    state.camera.angle = state.camera.angle > 0 ?
                           next_camera_angle * -1 :
                           next_camera_angle

    state.camera.x_offset = next_offset.randomize(:sign, :ratio)
    state.camera.y_offset = next_offset.randomize(:sign, :ratio)

    # Gracefully degrade trauma
    state.camera.trauma *= 0.95
  end
end

def tick args
  $screen_shake ||= ScreenShake.new
  $screen_shake.args = args
  $screen_shake.tick
end

Simple Camera - main.rb link

# ./samples/07_advanced_rendering/07_simple_camera/app/main.rb
def tick args
  # variables you can play around with
  args.state.world.w      ||= 1280
  args.state.world.h      ||= 720

  args.state.player.x     ||= 0
  args.state.player.y     ||= 0
  args.state.player.size  ||= 32

  args.state.enemy.x      ||= 700
  args.state.enemy.y      ||= 700
  args.state.enemy.size   ||= 16

  args.state.camera.x                ||= 640
  args.state.camera.y                ||= 300
  args.state.camera.scale            ||= 1.0
  args.state.camera.show_empty_space ||= :yes

  # instructions
  args.outputs.primitives << { x: 0, y:  80.from_top, w: 360, h: 80, r: 0, g: 0, b: 0, a: 128 }.solid!
  args.outputs.primitives << { x: 10, y: 10.from_top, text: "arrow keys to move around", r: 255, g: 255, b: 255}.label!
  args.outputs.primitives << { x: 10, y: 30.from_top, text: "+/- to change zoom of camera", r: 255, g: 255, b: 255}.label!
  args.outputs.primitives << { x: 10, y: 50.from_top, text: "tab to change camera edge behavior", r: 255, g: 255, b: 255}.label!

  # render scene
  args.outputs[:scene].w = args.state.world.w
  args.outputs[:scene].h = args.state.world.h

  args.outputs[:scene].solids << { x: 0, y: 0, w: args.state.world.w, h: args.state.world.h, r: 20, g: 60, b: 80 }
  args.outputs[:scene].solids << { x: args.state.player.x, y: args.state.player.y,
                                   w: args.state.player.size, h: args.state.player.size, r: 80, g: 155, b: 80 }
  args.outputs[:scene].solids << { x: args.state.enemy.x, y: args.state.enemy.y,
                                   w: args.state.enemy.size, h: args.state.enemy.size, r: 155, g: 80, b: 80 }

  # render camera
  scene_position = calc_scene_position args
  args.outputs.sprites << { x: scene_position.x,
                            y: scene_position.y,
                            w: scene_position.w,
                            h: scene_position.h,
                            path: :scene }

  # move player
  if args.inputs.directional_angle
    args.state.player.x += args.inputs.directional_angle.vector_x * 5
    args.state.player.y += args.inputs.directional_angle.vector_y * 5
    args.state.player.x  = args.state.player.x.clamp(0, args.state.world.w - args.state.player.size)
    args.state.player.y  = args.state.player.y.clamp(0, args.state.world.h - args.state.player.size)
  end

  # +/- to zoom in and out
  if args.inputs.keyboard.plus && Kernel.tick_count.zmod?(3)
    args.state.camera.scale += 0.05
  elsif args.inputs.keyboard.hyphen && Kernel.tick_count.zmod?(3)
    args.state.camera.scale -= 0.05
  elsif args.inputs.keyboard.key_down.tab
    if args.state.camera.show_empty_space == :yes
      args.state.camera.show_empty_space = :no
    else
      args.state.camera.show_empty_space = :yes
    end
  end

  args.state.camera.scale = args.state.camera.scale.greater(0.1)
end

def calc_scene_position args
  result = { x: args.state.camera.x - (args.state.player.x * args.state.camera.scale),
             y: args.state.camera.y - (args.state.player.y * args.state.camera.scale),
             w: args.state.world.w * args.state.camera.scale,
             h: args.state.world.h * args.state.camera.scale,
             scale: args.state.camera.scale }

  return result if args.state.camera.show_empty_space == :yes

  if result.w < args.grid.w
    result.merge!(x: (args.grid.w - result.w).half)
  elsif (args.state.player.x * result.scale) < args.grid.w.half
    result.merge!(x: 10)
  elsif (result.x + result.w) < args.grid.w
    result.merge!(x: - result.w + (args.grid.w - 10))
  end

  if result.h < args.grid.h
    result.merge!(y: (args.grid.h - result.h).half)
  elsif (result.y) > 10
    result.merge!(y: 10)
  elsif (result.y + result.h) < args.grid.h
    result.merge!(y: - result.h + (args.grid.h - 10))
  end

  result
end

Simple Camera Multiple Targets - main.rb link

# ./samples/07_advanced_rendering/07_simple_camera_multiple_targets/app/main.rb
def tick args
  args.outputs.background_color = [0, 0, 0]

  # variables you can play around with
  args.state.world.w                ||= 1280
  args.state.world.h                ||= 720
  args.state.target_hero            ||= :hero_1
  args.state.target_hero_changed_at ||= -30
  args.state.hero_size              ||= 32

  # initial state of heros and camera
  args.state.hero_1 ||= { x: 100, y: 100 }
  args.state.hero_2 ||= { x: 100, y: 600 }
  args.state.camera ||= { x: 640, y: 360, scale: 1.0 }

  # render instructions
  args.outputs.primitives << { x: 0,  y: 80.from_top, w: 360, h: 80, r: 0, g: 0, b: 0, a: 128 }.solid!
  args.outputs.primitives << { x: 10, y: 10.from_top, text: "+/- to change zoom of camera", r: 255, g: 255, b: 255}.label!
  args.outputs.primitives << { x: 10, y: 30.from_top, text: "arrow keys to move target hero", r: 255, g: 255, b: 255}.label!
  args.outputs.primitives << { x: 10, y: 50.from_top, text: "space to cycle target hero", r: 255, g: 255, b: 255}.label!

  # render scene
  args.outputs[:scene].w = args.state.world.w
  args.outputs[:scene].h = args.state.world.h

  # render world
  args.outputs[:scene].solids << { x: 0, y: 0, w: args.state.world.w, h: args.state.world.h, r: 20, g: 60, b: 80 }

  # render hero_1
  args.outputs[:scene].solids << { x: args.state.hero_1.x, y: args.state.hero_1.y,
                                   w: args.state.hero_size, h: args.state.hero_size, r: 255, g: 155, b: 80 }

  # render hero_2
  args.outputs[:scene].solids << { x: args.state.hero_2.x, y: args.state.hero_2.y,
                                   w: args.state.hero_size, h: args.state.hero_size, r: 155, g: 255, b: 155 }

  # render scene relative to camera
  scene_position = calc_scene_position args

  args.outputs.sprites << { x: scene_position.x,
                            y: scene_position.y,
                            w: scene_position.w,
                            h: scene_position.h,
                            path: :scene }

  # mini map
  args.outputs.borders << { x: 10,
                            y: 10,
                            w: args.state.world.w.idiv(8),
                            h: args.state.world.h.idiv(8),
                            r: 255,
                            g: 255,
                            b: 255 }
  args.outputs.sprites << { x: 10,
                            y: 10,
                            w: args.state.world.w.idiv(8),
                            h: args.state.world.h.idiv(8),
                            path: :scene }

  # cycle target hero
  if args.inputs.keyboard.key_down.space
    if args.state.target_hero == :hero_1
      args.state.target_hero = :hero_2
    else
      args.state.target_hero = :hero_1
    end
    args.state.target_hero_changed_at = Kernel.tick_count
  end

  # move target hero
  hero_to_move = if args.state.target_hero == :hero_1
                   args.state.hero_1
                 else
                   args.state.hero_2
                 end

  if args.inputs.directional_angle
    hero_to_move.x += args.inputs.directional_angle.vector_x * 5
    hero_to_move.y += args.inputs.directional_angle.vector_y * 5
    hero_to_move.x  = hero_to_move.x.clamp(0, args.state.world.w - hero_to_move.size)
    hero_to_move.y  = hero_to_move.y.clamp(0, args.state.world.h - hero_to_move.size)
  end

  # +/- to zoom in and out
  if args.inputs.keyboard.plus && Kernel.tick_count.zmod?(3)
    args.state.camera.scale += 0.05
  elsif args.inputs.keyboard.hyphen && Kernel.tick_count.zmod?(3)
    args.state.camera.scale -= 0.05
  end

  args.state.camera.scale = 0.1 if args.state.camera.scale < 0.1
end

def other_hero args
  if args.state.target_hero == :hero_1
    return args.state.hero_2
  else
    return args.state.hero_1
  end
end

def calc_scene_position args
  target_hero = if args.state.target_hero == :hero_1
                  args.state.hero_1
                else
                  args.state.hero_2
                end

  other_hero = if args.state.target_hero == :hero_1
                 args.state.hero_2
               else
                 args.state.hero_1
               end

  # calculate the lerp percentage based on the time since the target hero changed
  lerp_percentage = args.easing.ease args.state.target_hero_changed_at,
                                     Kernel.tick_count,
                                     30,
                                     :smooth_stop_quint,
                                     :flip

  # calculate the angle and distance between the target hero and the other hero
  angle_to_other_hero = args.geometry.angle_to target_hero, other_hero

  # calculate the distance between the target hero and the other hero
  distance_to_other_hero = args.geometry.distance target_hero, other_hero

  # the camera position is the target hero position plus the angle and distance to the other hero (lerped)
  { x: args.state.camera.x - (target_hero.x + (angle_to_other_hero.vector_x * distance_to_other_hero * lerp_percentage)) * args.state.camera.scale,
    y: args.state.camera.y - (target_hero.y + (angle_to_other_hero.vector_y * distance_to_other_hero * lerp_percentage)) * args.state.camera.scale,
    w: args.state.world.w * args.state.camera.scale,
    h: args.state.world.h * args.state.camera.scale }
end

Splitscreen Camera - main.rb link

# ./samples/07_advanced_rendering/08_splitscreen_camera/app/main.rb
class CameraMovement
  attr_accessor :state, :inputs, :outputs, :grid

  #==============================================================================================
  #Serialize
  def serialize
    {state: state, inputs: inputs, outputs: outputs, grid: grid }
  end

  def inspect
    serialize.to_s
  end

  def to_s
    serialize.to_s
  end

  #==============================================================================================
  #Tick
  def tick
    defaults
    calc
    render
    input
  end

  #==============================================================================================
  #Default functions
  def defaults
    outputs[:scene].background_color = [0,0,0]
    state.trauma ||= 0.0
    state.trauma_power ||= 2
    state.player_cyan ||= new_player_cyan
    state.player_magenta ||= new_player_magenta
    state.camera_magenta ||= new_camera_magenta
    state.camera_cyan ||= new_camera_cyan
    state.camera_center ||= new_camera_center
    state.room ||= new_room
  end

  def default_player x, y, w, h, sprite_path
    state.new_entity(:player,
                     { x: x,
                       y: y,
                       dy: 0,
                       dx: 0,
                       w: w,
                       h: h,
                       damage: 0,
                       dead: false,
                       orientation: "down",
                       max_alpha: 255,
                       sprite_path: sprite_path})
  end

  def default_floor_tile x, y, w, h, sprite_path
    state.new_entity(:room,
                     { x: x,
                       y: y,
                       w: w,
                       h: h,
                       sprite_path: sprite_path})
  end

  def default_camera x, y, w, h
    state.new_entity(:camera,
                     { x: x,
                       y: y,
                       dx: 0,
                       dy: 0,
                       w: w,
                       h: h})
  end

  def new_player_cyan
    default_player(0, 0, 64, 64,
                   "sprites/player/player_#{state.player_cyan.orientation}_standing.png")
  end

  def new_player_magenta
    default_player(64, 0, 64, 64,
                   "sprites/player/player_#{state.player_magenta.orientation}_standing.png")
  end

  def new_camera_magenta
    default_camera(0,0,720,720)
  end

  def new_camera_cyan
    default_camera(0,0,720,720)
  end

  def new_camera_center
    default_camera(0,0,1280,720)
  end


  def new_room
    default_floor_tile(0,0,1024,1024,'sprites/rooms/camera_room.png')
  end

  #==============================================================================================
  #Calculation functions
  def calc
    calc_camera_magenta
    calc_camera_cyan
    calc_camera_center
    calc_player_cyan
    calc_player_magenta
    calc_trauma_decay
  end

  def center_camera_tolerance
    return Math.sqrt(((state.player_magenta.x - state.player_cyan.x) ** 2) +
              ((state.player_magenta.y - state.player_cyan.y) ** 2)) > 640
  end

  def calc_player_cyan
    state.player_cyan.x += state.player_cyan.dx
    state.player_cyan.y += state.player_cyan.dy
  end

  def calc_player_magenta
    state.player_magenta.x += state.player_magenta.dx
    state.player_magenta.y += state.player_magenta.dy
  end

  def calc_camera_center
    timeScale = 1
    midX = (state.player_magenta.x + state.player_cyan.x)/2
    midY = (state.player_magenta.y + state.player_cyan.y)/2
    targetX = midX - state.camera_center.w/2
    targetY = midY - state.camera_center.h/2
    state.camera_center.x += (targetX - state.camera_center.x) * 0.1 * timeScale
    state.camera_center.y += (targetY - state.camera_center.y) * 0.1 * timeScale
  end


  def calc_camera_magenta
    timeScale = 1
    targetX = state.player_magenta.x + state.player_magenta.w - state.camera_magenta.w/2
    targetY = state.player_magenta.y + state.player_magenta.h - state.camera_magenta.h/2
    state.camera_magenta.x += (targetX - state.camera_magenta.x) * 0.1 * timeScale
    state.camera_magenta.y += (targetY - state.camera_magenta.y) * 0.1 * timeScale
  end

  def calc_camera_cyan
    timeScale = 1
    targetX = state.player_cyan.x + state.player_cyan.w - state.camera_cyan.w/2
    targetY = state.player_cyan.y + state.player_cyan.h - state.camera_cyan.h/2
    state.camera_cyan.x += (targetX - state.camera_cyan.x) * 0.1 * timeScale
    state.camera_cyan.y += (targetY - state.camera_cyan.y) * 0.1 * timeScale
  end

  def calc_player_quadrant angle
    if angle < 45 and angle > -45 and state.player_cyan.x < state.player_magenta.x
      return 1
    elsif angle < 45 and angle > -45 and state.player_cyan.x > state.player_magenta.x
      return 3
    elsif (angle > 45 or angle < -45) and state.player_cyan.y < state.player_magenta.y
      return 2
    elsif (angle > 45 or angle < -45) and state.player_cyan.y > state.player_magenta.y
      return 4
    end
  end

  def calc_camera_shake
    state.trauma
  end

  def calc_trauma_decay
    state.trauma = state.trauma * 0.9
  end

  def calc_random_float_range(min, max)
    rand * (max-min) + min
  end

  #==============================================================================================
  #Render Functions
  def render
    render_floor
    render_player_cyan
    render_player_magenta
    if center_camera_tolerance
      render_split_camera_scene
    else
      render_camera_center_scene
    end
  end

  def render_player_cyan
    outputs[:scene].sprites << {x: state.player_cyan.x,
                                y: state.player_cyan.y,
                                w: state.player_cyan.w,
                                h: state.player_cyan.h,
                                path: "sprites/player/player_#{state.player_cyan.orientation}_standing.png",
                                r: 0,
                                g: 255,
                                b: 255}
  end

  def render_player_magenta
    outputs[:scene].sprites << {x: state.player_magenta.x,
                                y: state.player_magenta.y,
                                w: state.player_magenta.w,
                                h: state.player_magenta.h,
                                path: "sprites/player/player_#{state.player_magenta.orientation}_standing.png",
                                r: 255,
                                g: 0,
                                b: 255}
  end

  def render_floor
    outputs[:scene].sprites << [state.room.x, state.room.y,
                                state.room.w, state.room.h,
                                state.room.sprite_path]
  end

  def render_camera_center_scene
    zoomFactor = 1
    outputs[:scene].width = state.room.w
    outputs[:scene].height = state.room.h

    maxAngle = 10.0
    maxOffset = 20.0
    angle = maxAngle * calc_camera_shake * calc_random_float_range(-1,1)
    offsetX = 32 - (maxOffset * calc_camera_shake * calc_random_float_range(-1,1))
    offsetY = 32 - (maxOffset * calc_camera_shake * calc_random_float_range(-1,1))

    outputs.sprites << {x: (-state.camera_center.x - offsetX)/zoomFactor,
                        y: (-state.camera_center.y - offsetY)/zoomFactor,
                        w: outputs[:scene].width/zoomFactor,
                        h: outputs[:scene].height/zoomFactor,
                        path: :scene,
                        angle: angle,
                        source_w: -1,
                        source_h: -1}
    outputs.labels << [128,64,"#{state.trauma.round(1)}",8,2,255,0,255,255]
  end

  def render_split_camera_scene
     outputs[:scene].width = state.room.w
     outputs[:scene].height = state.room.h
     render_camera_magenta_scene
     render_camera_cyan_scene

     angle = Math.atan((state.player_magenta.y - state.player_cyan.y)/(state.player_magenta.x- state.player_cyan.x)) * 180/Math::PI
     output_split_camera angle

  end

  def render_camera_magenta_scene
     zoomFactor = 1
     offsetX = 32
     offsetY = 32

     outputs[:scene_magenta].sprites << {x: (-state.camera_magenta.x*2),
                                         y: (-state.camera_magenta.y),
                                         w: outputs[:scene].width*2,
                                         h: outputs[:scene].height,
                                         path: :scene}

  end

  def render_camera_cyan_scene
    zoomFactor = 1
    offsetX = 32
    offsetY = 32
    outputs[:scene_cyan].sprites << {x: (-state.camera_cyan.x*2),
                                     y: (-state.camera_cyan.y),
                                     w: outputs[:scene].width*2,
                                     h: outputs[:scene].height,
                                     path: :scene}
  end

  def output_split_camera angle
    #TODO: Clean this up!
    quadrant = calc_player_quadrant angle
    outputs.labels << [128,64,"#{quadrant}",8,2,255,0,255,255]
    if quadrant == 1
      set_camera_attributes(w: 640, h: 720, m_x: 640, m_y: 0, c_x: 0, c_y: 0)

    elsif quadrant == 2
      set_camera_attributes(w: 1280, h: 360, m_x: 0, m_y: 360, c_x: 0, c_y: 0)

    elsif quadrant == 3
      set_camera_attributes(w: 640, h: 720, m_x: 0, m_y: 0, c_x: 640, c_y: 0)

    elsif quadrant == 4
      set_camera_attributes(w: 1280, h: 360, m_x: 0, m_y: 0, c_x: 0, c_y: 360)

    end
  end

  def set_camera_attributes(w: 0, h: 0, m_x: 0, m_y: 0, c_x: 0, c_y: 0)
    state.camera_cyan.w = w + 64
    state.camera_cyan.h = h + 64
    outputs[:scene_cyan].width = (w) * 2
    outputs[:scene_cyan].height = h

    state.camera_magenta.w = w + 64
    state.camera_magenta.h = h + 64
    outputs[:scene_magenta].width = (w) * 2
    outputs[:scene_magenta].height = h
    outputs.sprites << {x: m_x,
                        y: m_y,
                        w: w,
                        h: h,
                        path: :scene_magenta}
    outputs.sprites << {x: c_x,
                        y: c_y,
                        w: w,
                        h: h,
                        path: :scene_cyan}
  end

  def add_trauma amount
    state.trauma = [state.trauma + amount, 1.0].min
  end

  def remove_trauma amount
    state.trauma = [state.trauma - amount, 0.0].max
  end
  #==============================================================================================
  #Input functions
  def input
    input_move_cyan
    input_move_magenta

    if inputs.keyboard.key_down.t
      add_trauma(0.5)
    elsif inputs.keyboard.key_down.y
      remove_trauma(0.1)
    end
  end

  def input_move_cyan
    if inputs.keyboard.key_held.up
      state.player_cyan.dy = 5
      state.player_cyan.orientation = "up"
    elsif inputs.keyboard.key_held.down
      state.player_cyan.dy = -5
      state.player_cyan.orientation = "down"
    else
      state.player_cyan.dy *= 0.8
    end
    if inputs.keyboard.key_held.left
      state.player_cyan.dx = -5
      state.player_cyan.orientation = "left"
    elsif inputs.keyboard.key_held.right
      state.player_cyan.dx = 5
      state.player_cyan.orientation = "right"
    else
      state.player_cyan.dx *= 0.8
    end

    outputs.labels << [128,512,"#{state.player_cyan.x.round()}",8,2,0,255,255,255]
    outputs.labels << [128,480,"#{state.player_cyan.y.round()}",8,2,0,255,255,255]
  end

  def input_move_magenta
    if inputs.keyboard.key_held.w
      state.player_magenta.dy = 5
      state.player_magenta.orientation = "up"
    elsif inputs.keyboard.key_held.s
      state.player_magenta.dy = -5
      state.player_magenta.orientation = "down"
    else
      state.player_magenta.dy *= 0.8
    end
    if inputs.keyboard.key_held.a
      state.player_magenta.dx = -5
      state.player_magenta.orientation = "left"
    elsif inputs.keyboard.key_held.d
      state.player_magenta.dx = 5
      state.player_magenta.orientation = "right"
    else
      state.player_magenta.dx *= 0.8
    end

    outputs.labels << [128,360,"#{state.player_magenta.x.round()}",8,2,255,0,255,255]
    outputs.labels << [128,328,"#{state.player_magenta.y.round()}",8,2,255,0,255,255]
  end
end

$camera_movement = CameraMovement.new

def tick args
  args.outputs.background_color = [0,0,0]
  $camera_movement.inputs  = args.inputs
  $camera_movement.outputs = args.outputs
  $camera_movement.state   = args.state
  $camera_movement.grid    = args.grid
  $camera_movement.tick
end

Z Targeting Camera - main.rb link

# ./samples/07_advanced_rendering/09_z_targeting_camera/app/main.rb
class Game
  attr_gtk

  def tick
    defaults
    render
    input
    calc
  end

  def defaults
    outputs.background_color = [219, 208, 191]
    player.x        ||= 634
    player.y        ||= 153
    player.angle    ||= 90
    player.distance ||= arena_radius
    target.x        ||= 634
    target.y        ||= 359
  end

  def render
    outputs[:scene].sprites << ({ x: 0, y: 0, w: 933, h: 700, path: 'sprites/arena.png' }.center_inside_rect grid.rect)
    outputs[:scene].sprites << target_sprite
    outputs[:scene].sprites << player_sprite
    outputs.sprites << scene
  end

  def target_sprite
    {
      x: target.x, y: target.y,
      w: 10, h: 10,
      path: 'sprites/square/black.png'
    }.anchor_rect 0.5, 0.5
  end

  def input
    if inputs.up && player.distance > 30
      player.distance -= 2
    elsif inputs.down && player.distance < 200
      player.distance += 2
    end

    player.angle += inputs.left_right * -1
  end

  def calc
    player.x = target.x + ((player.angle *  1).vector_x player.distance)
    player.y = target.y + ((player.angle * -1).vector_y player.distance)
  end

  def player_sprite
    {
      x: player.x,
      y: player.y,
      w: 50,
      h: 100,
      path: 'sprites/player.png',
      angle: (player.angle * -1) + 90
    }.anchor_rect 0.5, 0
  end

  def center_map
    { x: 634, y: 359 }
  end

  def zoom_factor_single
    2 - ((args.geometry.distance player, center_map).fdiv arena_radius)
  end

  def zoom_factor
    zoom_factor_single ** 2
  end

  def arena_radius
    206
  end

  def scene
    {
      x:    (640 - player.x) + (640 - (640 * zoom_factor)),
      y:    (360 - player.y - (75 * zoom_factor)) + (320 - (320 * zoom_factor)),
      w:    1280 * zoom_factor,
      h:     720 * zoom_factor,
      path: :scene,
      angle: player.angle - 90,
      angle_anchor_x: (player.x.fdiv 1280),
      angle_anchor_y: (player.y.fdiv 720)
    }
  end

  def player
    state.player
  end

  def target
    state.target
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

$gtk.reset

Camera And Large Map - main.rb link

# ./samples/07_advanced_rendering/10_camera_and_large_map/app/main.rb
def tick args
  # you want to make sure all of your pngs are a maximum size of 1280x1280
  # low-end android devices and machines with underpowered GPUs are unable to
  # load very large textures.

  # this sample app creates 640x640 tiles of a 6400x6400 pixel png and displays them
  # on the screen relative to the player's position

  # tile creation process
  create_tiles_if_needed args

  # if tiles are already present the show map
  display_tiles args
end

def display_tiles args
  # set the player's starting location
  args.state.player ||= {
    x:  0,
    y:  0,
    w: 40,
    h: 40,
    path: "sprites/square/blue.png"
  }

  # if all tiles have been created, then we are
  # in "displaying_tiles" mode
  if args.state.displaying_tiles
    # create a render target that can hold 9 640x640 tiles
    args.outputs[:scene].background_color = [0, 0, 0, 0]
    args.outputs[:scene].w = 1920
    args.outputs[:scene].h = 1920

    # allow player to be moved with arrow keys
    args.state.player.x += args.inputs.left_right * 10
    args.state.player.y += args.inputs.up_down * 10

    # given the player's location, return a collection of primitives
    # to render that are within the 1920x1920 viewport
    args.outputs[:scene].primitives << tiles_in_viewport(args)

    # place the player in the center of the render_target
    args.outputs[:scene].primitives << {
      x: 960 - 20,
      y: 960 - 20,
      w: 40,
      h: 40,
      path: "sprites/square/blue.png"
    }

    # center the 1920x1920 render target within the 1280x720 window
    args.outputs.sprites << {
      x: -320,
      y: -600,
      w: 1920,
      h: 1920,
      path: :scene
    }
  end
end

def tiles_in_viewport args
  state = args.state
  # define the size of each tile
  tile_size = 640

  # determine what tile the player is on
  tile_player_is_on = { x: state.player.x.idiv(tile_size), y: state.player.y.idiv(tile_size) }

  # calculate the x and y offset of the player so that tiles are positioned correctly
  offset_x = 960 - (state.player.x - (tile_player_is_on.x * tile_size))
  offset_y = 960 - (state.player.y - (tile_player_is_on.y * tile_size))

  primitives = []

  # get 9 tiles in total (the tile the player is on and the 8 surrounding tiles)

  # center tile
  primitives << (tile_in_viewport size:       tile_size,
                                  from_row:   tile_player_is_on.y,
                                  from_col:   tile_player_is_on.x,
                                  offset_row: 0,
                                  offset_col: 0,
                                  dy:         offset_y,
                                  dx:         offset_x)

  # tile to the right
  primitives << (tile_in_viewport size:       tile_size,
                                  from_row:   tile_player_is_on.y,
                                  from_col:   tile_player_is_on.x,
                                  offset_row: 0,
                                  offset_col: 1,
                                  dy:         offset_y,
                                  dx:         offset_x)
  # tile to the left
  primitives << (tile_in_viewport size:        tile_size,
                                  from_row:    tile_player_is_on.y,
                                  from_col:    tile_player_is_on.x,
                                  offset_row:  0,
                                  offset_col: -1,
                                  dy:          offset_y,
                                  dx:          offset_x)

  # tile directly above
  primitives << (tile_in_viewport size:       tile_size,
                                  from_row:   tile_player_is_on.y,
                                  from_col:   tile_player_is_on.x,
                                  offset_row: 1,
                                  offset_col: 0,
                                  dy:         offset_y,
                                  dx:         offset_x)
  # tile directly below
  primitives << (tile_in_viewport size:         tile_size,
                                  from_row:     tile_player_is_on.y,
                                  from_col:     tile_player_is_on.x,
                                  offset_row:  -1,
                                  offset_col:   0,
                                  dy:           offset_y,
                                  dx:           offset_x)
  # tile up and to the left
  primitives << (tile_in_viewport size:        tile_size,
                                  from_row:    tile_player_is_on.y,
                                  from_col:    tile_player_is_on.x,
                                  offset_row:  1,
                                  offset_col: -1,
                                  dy:          offset_y,
                                  dx:          offset_x)

  # tile up and to the right
  primitives << (tile_in_viewport size:       tile_size,
                                  from_row:   tile_player_is_on.y,
                                  from_col:   tile_player_is_on.x,
                                  offset_row: 1,
                                  offset_col: 1,
                                  dy:         offset_y,
                                  dx:         offset_x)

  # tile down and to the left
  primitives << (tile_in_viewport size:        tile_size,
                                  from_row:    tile_player_is_on.y,
                                  from_col:    tile_player_is_on.x,
                                  offset_row: -1,
                                  offset_col: -1,
                                  dy:          offset_y,
                                  dx:          offset_x)

  # tile down and to the right
  primitives << (tile_in_viewport size:        tile_size,
                                  from_row:    tile_player_is_on.y,
                                  from_col:    tile_player_is_on.x,
                                  offset_row: -1,
                                  offset_col:  1,
                                  dy:          offset_y,
                                  dx:          offset_x)

  primitives
end

def tile_in_viewport size:, from_row:, from_col:, offset_row:, offset_col:, dy:, dx:;
  x = size * offset_col + dx
  y = size * offset_row + dy

  return nil if (from_row + offset_row) < 0
  return nil if (from_row + offset_row) > 9

  return nil if (from_col + offset_col) < 0
  return nil if (from_col + offset_col) > 9

  # return the tile sprite, a border demarcation, and label of which tile x and y
  [
    {
      x: x,
      y: y,
      w: size,
      h: size,
      path: "sprites/tile-#{from_col + offset_col}-#{from_row + offset_row}.png",
    },
    {
      x: x,
      y: y,
      w: size,
      h: size,
      r: 255,
      primitive_marker: :border,
    },
    {
      x: x + size / 2 - 150,
      y: y + size / 2 - 25,
      w: 300,
      h: 50,
      primitive_marker: :solid,
      r: 0,
      g: 0,
      b: 0,
      a: 128
    },
    {
      x: x + size / 2,
      y: y + size / 2,
      text: "tile #{from_col + offset_col}, #{from_row + offset_row}",
      alignment_enum: 1,
      vertical_alignment_enum: 1,
      size_enum: 2,
      r: 255,
      g: 255,
      b: 255
    },
  ]
end

def create_tiles_if_needed args
  # We are going to use args.outputs.screenshots to generate tiles of a
  # png of size 6400x6400 called sprites/large.png.
  if !args.gtk.stat_file("sprites/tile-9-9.png") && !args.state.creating_tiles
    args.state.displaying_tiles = false
    args.outputs.labels << {
      x: 960,
      y: 360,
      text: "Press enter to generate tiles of sprites/large.png.",
      alignment_enum: 1,
      vertical_alignment_enum: 1
    }
  elsif !args.state.creating_tiles
    args.state.displaying_tiles = true
  end

  # pressing enter will start the tile creation process
  if args.inputs.keyboard.key_down.enter && !args.state.creating_tiles
    args.state.displaying_tiles = false
    args.state.creating_tiles = true
    args.state.tile_clock = 0
  end

  # the tile creation process renders an area of sprites/large.png
  # to the screen and takes a screenshot of it every half second
  # until all tiles are generated.
  # once all tiles are generated a map viewport will be rendered that
  # stitches tiles together.
  if args.state.creating_tiles
    args.state.tile_x ||= 0
    args.state.tile_y ||= 0

    # render a sub-square of the large png.
    args.outputs.sprites << {
      x: 0,
      y: 0,
      w: 640,
      h: 640,
      source_x: args.state.tile_x * 640,
      source_y: args.state.tile_y * 640,
      source_w: 640,
      source_h: 640,
      path: "sprites/large.png"
    }

    # determine tile file name
    tile_path = "sprites/tile-#{args.state.tile_x}-#{args.state.tile_y}.png"

    args.outputs.labels << {
      x: 960,
      y: 320,
      text: "Generating #{tile_path}",
      alignment_enum: 1,
      vertical_alignment_enum: 1
    }

    # take a screenshot on frames divisible by 29
    if args.state.tile_clock.zmod?(29)
      args.outputs.screenshots << {
        x: 0,
        y: 0,
        w: 640,
        h: 640,
        path: tile_path,
        a: 255
      }
    end

    # increment tile to render on frames divisible by 30 (half a second)
    # (one frame is allotted to take screenshot)
    if args.state.tile_clock.zmod?(30)
      args.state.tile_x += 1
      if args.state.tile_x >= 10
        args.state.tile_x  = 0
        args.state.tile_y += 1
      end

      # once all of tile tiles are created, begin displaying map
      if args.state.tile_y >= 10
        args.state.creating_tiles = false
        args.state.displaying_tiles = true
      end
    end

    args.state.tile_clock += 1
  end
end

$gtk.reset

Camera And Large Sprites - main.rb link

# ./samples/07_advanced_rendering/10_camera_and_large_sprites/app/main.rb
# When using a render target as a camera, sprite rendered
# within the camera can become very large and tax the GPU. This
# example shows how to calculate the crop rectangle for the sprite and only
# render the portion of the sprite that is visible within the camera.
class Game
  attr :args

  def tick
    defaults
    calc
    render
  end

  def defaults
    @args.state ||= {
      orbit: {
        x: 640,
        y: 640,
        w: 1280,
        h: 1280,
        anchor_x: 0.5,
        anchor_y: 0.5
      },
      viewport: {
        x: 0,
        y: 0,
        w: 720,
        h: 720
      },
      camera: {
        x: 0,
        y: 0,
        scale: 0.25,
        w: 720,
        h: 720
      }
    }

    if [email protected]_sprite_size
      w, h = $gtk.calcspritebox("sprites/ring-1280.png")
      @args.state.orbit_sprite_size = {
        w: w,
        h: h
      }
    end
  end

  def calc
    if inputs.keyboard.i
      state.camera.scale += 0.005 * state.camera.scale
    elsif inputs.keyboard.o
      state.camera.scale -= 0.005 * state.camera.scale
    end

    if inputs.keyboard.d
      state.camera.x += 10 / state.camera.scale
    elsif inputs.keyboard.a
      state.camera.x -= 10 / state.camera.scale
    end

    if inputs.keyboard.s
      state.camera.y -= 10 / state.camera.scale
    elsif inputs.keyboard.w
      state.camera.y += 10 / state.camera.scale
    end

    state.camera.scale = state.camera.scale.clamp(0.25, 10)
    state.camera.x = state.camera.x.round(2)
    state.camera.y = state.camera.y.round(2)

    state.orbit_in_camera = {
      x: (state.orbit.x - state.camera.x) * state.camera.scale,
      y: (state.orbit.y - state.camera.y) * state.camera.scale,
      w: state.orbit.w * state.camera.scale,
      h: state.orbit.h * state.camera.scale,
      anchor_x: state.orbit.anchor_x,
      anchor_y: state.orbit.anchor_y
    }
  end

  def render
    outputs.background_color = [32, 32, 32]

    outputs[:scene].w = 720
    outputs[:scene].h = 720
    outputs[:scene].background_color = [0, 0, 0, 0]

    orbit_sprite_rect = sprite_rect state.viewport, state.orbit_in_camera, state.orbit_sprite_size
    outputs[:scene].sprites << {
      **orbit_sprite_rect,
      path: "sprites/ring-1280.png"
    }

    outputs.borders << {
      x: Grid.w / 2,
      y: Grid.h / 2,
      w: 720,
      h: 720,
      path: :scene,
      anchor_x: 0.5,
      anchor_y: 0.5,
      r: 255,
      g: 255,
      b: 255
    }

    outputs.sprites << {
      x: Grid.w / 2,
      y: Grid.h / 2,
      w: 720,
      h: 720,
      path: :scene,
      anchor_x: 0.5,
      anchor_y: 0.5
    }

    outputs.watch("Instructions WASD: move camera, I: zoom in, O: zoom out")
    outputs.watch("state.camera:    #{state.camera.to_sf}")
    outputs.watch("orbit_in_camera: #{state.orbit_in_camera.to_sf}")
    outputs.watch("sprite_rect:     #{orbit_sprite_rect.to_sf}")
  end

  def sprite_rect viewport_rect, destination_rect, sprite_size
    ratio = destination_rect.w / sprite_size.w

    # if the destination rect is not within the viewport, return an empty rect
    if !Geometry.intersect_rect? viewport_rect, destination_rect
      return { x: 0, y: 0, w: 0, h: 0 }
    end

    # Geometry.rect_props returns a hash with x, y, w, h (removes/recomputes anchor_x, anchor_y)
    destination_rect = Geometry.rect_props destination_rect
    viewport_rect = Geometry.rect_props viewport_rect

    # calculate the x, w, source_x, source_w of the sprite
    destination_left = destination_rect.x
    viewport_left = viewport_rect.x
    destination_right = destination_rect.x + destination_rect.w
    viewport_right = viewport_rect.x + viewport_rect.w
    left_diff = viewport_left - destination_left
    right_diff = destination_right - viewport_right

    if destination_left <= viewport_left && destination_right >= viewport_right
      # destination rect's x, w is larger than the viewport
      x = viewport_left
      w = destination_rect.w - (viewport_left - destination_left) - right_diff
      source_x = 0 + left_diff / ratio
      source_w = sprite_size.w - left_diff / ratio - right_diff / ratio
    elsif destination_left <= viewport_left && destination_right <= viewport_right
      # destination rect's x, w is partially within the viewport
      x = viewport_left
      w = destination_rect.w - (viewport_left - destination_left)
      source_x = 0 + left_diff / ratio
      source_w = sprite_size.w - left_diff / ratio
    elsif destination_right >= viewport_right && destination_left >= viewport_left
      # destination rect's x, w is partially within the viewport
      x = destination_left
      w = destination_rect.w - right_diff
      source_x = 0
      source_w = sprite_size.w - right_diff / ratio
    else
      # destination rect's x, w is completely within the viewport
      x = destination_left
      w = destination_rect.w
      source_x = 0
      source_w = sprite_size.w
    end

    # calculate the y, h, source_y, source_h of the sprite
    destination_top = destination_rect.y + destination_rect.h
    viewport_top = viewport_rect.y + viewport_rect.h
    destination_bottom = destination_rect.y
    viewport_bottom = viewport_rect.y
    bottom_diff = viewport_bottom - destination_bottom
    top_diff = destination_top - viewport_top

    if destination_top >= viewport_top && destination_bottom <= viewport_bottom
      # destination rect's y, h is larger than the viewport
      y = viewport_bottom
      h = destination_rect.h - (viewport_bottom - destination_bottom) - top_diff
      source_y = 0 + (viewport_bottom - destination_bottom) / ratio
      source_h = sprite_size.h - (viewport_bottom - destination_bottom) / ratio - top_diff / ratio
    elsif destination_top >= viewport_top && destination_bottom >= viewport_bottom
      # destination rect's y, h is partially within the viewport
      y = destination_bottom
      h = destination_rect.h - top_diff
      source_y = 0
      source_h = sprite_size.h - top_diff / ratio
    elsif destination_bottom <= viewport_bottom && destination_top <= viewport_top
      # destination rect's y, h is partially within the viewport
      source_y = 0 + bottom_diff / ratio
      source_h = sprite_size.h - bottom_diff / ratio
      y = viewport_bottom
      h = destination_rect.h - bottom_diff
    else
      # destination rect's y, h is completely within the viewport
      y = destination_bottom
      h = destination_rect.h
      source_y = 0
      source_h = sprite_size.h
    end

    # return the calculated values
    {
      x: x,
      y: y,
      w: w,
      h: h,
      source_x: source_x,
      source_y: source_y,
      source_w: source_w,
      source_h: source_h
    }
  end

  def state
    @args.state
  end

  def outputs
    @args.outputs
  end

  def inputs
    @args.inputs
  end
end

def boot args
  args.state = nil
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

def reset args
  $game = nil
end

GTK.reset

Blend Modes - main.rb link

# ./samples/07_advanced_rendering/11_blend_modes/app/main.rb
$gtk.reset

def draw_blendmode args, mode
  w = 160
  h = w
  args.state.x += (1280-w) / (args.state.blendmodes.length + 1)
  x = args.state.x
  y = (720 - h) / 2
  s = 'sprites/blue-feathered.png'
  args.outputs.sprites << { blendmode_enum: mode.value, x: x, y: y, w: w, h: h, path: s }
  args.outputs.labels << [x + (w/2), y, mode.name.to_s, 1, 1, 255, 255, 255]
end

def tick args

  # Different blend modes do different things, depending on what they
  # blend against (in this case, the pixels of the background color).
  args.state.bg_element ||= 1
  args.state.bg_color ||= 255
  args.state.bg_color_direction ||= 1
  bg_r = (args.state.bg_element == 1) ? args.state.bg_color : 0
  bg_g = (args.state.bg_element == 2) ? args.state.bg_color : 0
  bg_b = (args.state.bg_element == 3) ? args.state.bg_color : 0
  args.state.bg_color += args.state.bg_color_direction
  if (args.state.bg_color_direction > 0) && (args.state.bg_color >= 255)
    args.state.bg_color_direction = -1
    args.state.bg_color = 255
  elsif (args.state.bg_color_direction < 0) && (args.state.bg_color <= 0)
    args.state.bg_color_direction = 1
    args.state.bg_color = 0
    args.state.bg_element += 1
    if args.state.bg_element >= 4
      args.state.bg_element = 1
    end
  end

  args.outputs.background_color = [ bg_r, bg_g, bg_b, 255 ]

  args.state.blendmodes ||= [
    { name: :none,  value: 0 },
    { name: :blend, value: 1 },
    { name: :add,   value: 2 },
    { name: :mod,   value: 3 },
    { name: :mul,   value: 4 }
  ]

  args.state.x = 0  # reset this, draw_blendmode will increment it.
  args.state.blendmodes.each { |blendmode| draw_blendmode args, blendmode }
end

Blend Modes Additive Modulo - main.rb link

# ./samples/07_advanced_rendering/12_blend_modes_additive_modulo/app/main.rb
# Sample app shows how to use blend modes to create a masking layer
# Special thanks to akzidenz@discord (https://akzidenz.itch.io/) for providing this sample app
#
# blendmode_enum reference:
#  0: no blend
#  1: alpha blending (default)
#  2: additive blending
#  3: modulo blending
#  4: multiply blending
def tick args
  # create a render target to represent the masking layer
  args.outputs[:mask].w = 1280
  args.outputs[:mask].h = 720

  # don't erase the texture when new items are added
  args.outputs[:mask].clear_before_render = false

  # the "cover" only goes in once
  if Kernel.tick_count == 0
    # place a black background in the render target
    args.outputs[:mask].sprites << {
      x: 0, y: 0, w: 1280, h: 720,
      path: :solid,
      r: 0, g: 0, b: 0 # <-- important (black color)
    }
  end

  # the "reveal" sprite is added to the render target
  # when the left mouse button is clicked or held
  # NOTE: setting `clear_before_render = false` keeps the RT from resetting
  #       when a new primitive is drawn to it
  if args.inputs.mouse.key_down.left || args.inputs.mouse.key_held.left
    args.outputs[:mask].sprites << {
      x: args.inputs.mouse.x,
      y: args.inputs.mouse.y,
      w: 240, h: 240,
      anchor_x: 0.5,
      anchor_y: 0.5,
      path: 'sprites/mask.png', # <-- sprite representing the "reveal shape"
      blendmode_enum: 2,        # <-- important (2 means additive blending)
      r: 255, g: 255, b: 255    # <-- important (white color)
    }
  end

  # render background to reveal
  args.outputs.sprites << { x: 0,
                            y: 0,
                            w: 1280,
                            h: 720,
                            path: 'sprites/bg.png' }

  # render masking layer over the bg to reveal
  args.outputs.sprites << {
    x: 0, y: 0, w: 1280, h: 720,
    path: :mask,
    blendmode_enum: 3 # <-- important (3 means modulo blending)
  }

  # render mouse overlay
  args.outputs.sprites << {
    x: args.inputs.mouse.x,
    y: args.inputs.mouse.y,
    w: 180, h: 180,
    anchor_x: 0.5, anchor_y: 0.5,
    a: 32
  }

  # render instructions
  args.outputs.labels << { x: 8,
                           y: 720 - 8,
                           text: "click/drag move to uncover bg image",
                           r: 255,
                           g: 255,
                           b: 255 }
end

Render Target Noclear - main.rb link

# ./samples/07_advanced_rendering/12_render_target_noclear/app/main.rb
def tick args
  args.state.x ||= 500
  args.state.y ||= 350
  args.state.xinc ||= 7
  args.state.yinc ||= 7
  args.state.bgcolor ||= 1
  args.state.bginc ||= 1

  # clear the render target on the first tick, and then never again. Draw
  #  another box to it every tick, accumulating over time.
  clear_target = (Kernel.tick_count == 0) || (args.inputs.keyboard.key_down.space)
  args.render_target(:accumulation).background_color = [ 0, 0, 0, 0 ];
  args.render_target(:accumulation).clear_before_render = clear_target
  args.render_target(:accumulation).solids << [args.state.x, args.state.y, 25, 25, 255, 0, 0, 255];
  args.state.x += args.state.xinc
  args.state.y += args.state.yinc
  args.state.bgcolor += args.state.bginc

  # animation upkeep...change where we draw the next box and what color the
  #  window background will be.
  if args.state.xinc > 0 && args.state.x >= 1280
    args.state.xinc = -7
  elsif args.state.xinc < 0 && args.state.x < 0
    args.state.xinc = 7
  end

  if args.state.yinc > 0 && args.state.y >= 720
    args.state.yinc = -7
  elsif args.state.yinc < 0 && args.state.y < 0
    args.state.yinc = 7
  end

  if args.state.bginc > 0 && args.state.bgcolor >= 255
    args.state.bginc = -1
  elsif args.state.bginc < 0 && args.state.bgcolor <= 0
    args.state.bginc = 1
  end

  # clear the screen to a shade of blue and draw the render target, which
  #  is not clearing every frame, on top of it. Note that you can NOT opt to
  #  skip clearing the screen, only render targets. The screen clears every
  #  frame; double-buffering would prevent correct updates between frames.
  args.outputs.background_color = [ 0, 0, args.state.bgcolor, 255 ]
  args.outputs.sprites << [ 0, 0, 1280, 720, :accumulation ]
end

$gtk.reset

Lighting - main.rb link

# ./samples/07_advanced_rendering/13_lighting/app/main.rb
def calc args
  args.state.swinging_light_sign     ||= 1
  args.state.swinging_light_start_at ||= 0
  args.state.swinging_light_duration ||= 300
  args.state.swinging_light_perc       = args.state
                                             .swinging_light_start_at
                                             .ease_spline_extended Kernel.tick_count,
                                                                   args.state.swinging_light_duration,
                                                                   [
                                                                     [0.0, 1.0, 1.0, 1.0],
                                                                     [1.0, 1.0, 1.0, 0.0]
                                                                   ]
  args.state.max_swing_angle ||= 45

  if args.state.swinging_light_start_at.elapsed_time > args.state.swinging_light_duration
    args.state.swinging_light_start_at = Kernel.tick_count
    args.state.swinging_light_sign *= -1
  end

  args.state.swinging_light_angle = 360 + ((args.state.max_swing_angle * args.state.swinging_light_perc) * args.state.swinging_light_sign)
end

def render args
  args.outputs.background_color = [0, 0, 0]

  # render scene
  args.outputs[:scene].sprites << { x:        0, y:   0, w: 1280, h: 720, path: :pixel }
  args.outputs[:scene].sprites << { x: 640 - 40, y: 100, w:   80, h:  80, path: 'sprites/square/blue.png' }
  args.outputs[:scene].sprites << { x: 640 - 40, y: 200, w:   80, h:  80, path: 'sprites/square/blue.png' }
  args.outputs[:scene].sprites << { x: 640 - 40, y: 300, w:   80, h:  80, path: 'sprites/square/blue.png' }
  args.outputs[:scene].sprites << { x: 640 - 40, y: 400, w:   80, h:  80, path: 'sprites/square/blue.png' }
  args.outputs[:scene].sprites << { x: 640 - 40, y: 500, w:   80, h:  80, path: 'sprites/square/blue.png' }

  # render light
  swinging_light_w = 1100
  args.outputs[:lights].background_color = [0, 0, 0, 0]
  args.outputs[:lights].sprites << { x: 640 - swinging_light_w.half,
                                     y: -1300,
                                     w: swinging_light_w,
                                     h: 3000,
                                     angle_anchor_x: 0.5,
                                     angle_anchor_y: 1.0,
                                     path: "sprites/lights/mask.png",
                                     angle: args.state.swinging_light_angle }

  args.outputs[:lights].sprites << { x: args.inputs.mouse.x - 400,
                                     y: args.inputs.mouse.y - 400,
                                     w: 800,
                                     h: 800,
                                     path: "sprites/lights/mask.png" }

  # merge unlighted scene with lights
  args.outputs[:lighted_scene].sprites << { x: 0, y: 0, w: 1280, h: 720, path: :lights, blendmode_enum: 0 }
  args.outputs[:lighted_scene].sprites << { blendmode_enum: 2, x: 0, y: 0, w: 1280, h: 720, path: :scene }

  # output lighted scene to main canvas
  args.outputs.sprites << { x: 0, y: 0, w: 1280, h: 720, path: :lighted_scene }

  # render lights and scene render_targets as a mini map
  args.outputs.debug  << { x: 16,      y: (16 + 90).from_top, w: 160, h: 90, r: 255, g: 255, b: 255 }.solid!
  args.outputs.debug  << { x: 16,      y: (16 + 90).from_top, w: 160, h: 90, path: :lights }
  args.outputs.debug  << { x: 16 + 80, y: (16 + 90 + 8).from_top, text: ":lights render_target", r: 255, g: 255, b: 255, size_enum: -3, alignment_enum: 1 }

  args.outputs.debug  << { x: 16 + 160 + 16,      y: (16 + 90).from_top, w: 160, h: 90, r: 255, g: 255, b: 255 }.solid!
  args.outputs.debug  << { x: 16 + 160 + 16,      y: (16 + 90).from_top, w: 160, h: 90, path: :scene }
  args.outputs.debug  << { x: 16 + 160 + 16 + 80, y: (16 + 90 + 8).from_top, text: ":scene render_target", r: 255, g: 255, b: 255, size_enum: -3, alignment_enum: 1 }
end

def tick args
  render args
  calc args
end

$gtk.reset

Triangles - main.rb link

# ./samples/07_advanced_rendering/14_triangles/app/main.rb
def tick args
  dragonruby_logo_width  = 128
  dragonruby_logo_height = 101

  row_0 = 400
  row_1 = 250

  col_0 = 384 - dragonruby_logo_width.half + dragonruby_logo_width * 0
  col_1 = 384 - dragonruby_logo_width.half + dragonruby_logo_width * 1
  col_2 = 384 - dragonruby_logo_width.half + dragonruby_logo_width * 2
  col_3 = 384 - dragonruby_logo_width.half + dragonruby_logo_width * 3
  col_4 = 384 - dragonruby_logo_width.half + dragonruby_logo_width * 4

  # row 0
  args.outputs.solids << make_triangle(
    col_0,
    row_0,
    col_0 + dragonruby_logo_width.half,
    row_0 + dragonruby_logo_height,
    col_0 + dragonruby_logo_width.half + dragonruby_logo_width.half,
    row_0,
    0, 128, 128,
    128
  )

  args.outputs.solids << {
    x:  col_1,
    y:  row_0,
    x2: col_1 + dragonruby_logo_width.half,
    y2: row_0 + dragonruby_logo_height,
    x3: col_1 + dragonruby_logo_width,
    y3: row_0,
  }

  args.outputs.sprites << {
    x:  col_2,
    y:  row_0,
    w:  dragonruby_logo_width,
    h:  dragonruby_logo_height,
    path: 'dragonruby.png'
  }

  args.outputs.sprites << {
    x:  col_3,
    y:  row_0,
    x2: col_3 + dragonruby_logo_width.half,
    y2: row_0 + dragonruby_logo_height,
    x3: col_3 + dragonruby_logo_width,
    y3: row_0,
    path: 'dragonruby.png',
    source_x:  0,
    source_y:  0,
    source_x2: dragonruby_logo_width.half,
    source_y2: dragonruby_logo_height,
    source_x3: dragonruby_logo_width,
    source_y3: 0
  }

  args.outputs.sprites << TriangleLogo.new(x:  col_4,
                                           y:  row_0,
                                           x2: col_4 + dragonruby_logo_width.half,
                                           y2: row_0 + dragonruby_logo_height,
                                           x3: col_4 + dragonruby_logo_width,
                                           y3: row_0,
                                           path: 'dragonruby.png',
                                           source_x:  0,
                                           source_y:  0,
                                           source_x2: dragonruby_logo_width.half,
                                           source_y2: dragonruby_logo_height,
                                           source_x3: dragonruby_logo_width,
                                           source_y3: 0)

  # row 1
  args.outputs.primitives << make_triangle(
    col_0,
    row_1,
    col_0 + dragonruby_logo_width.half,
    row_1 + dragonruby_logo_height,
    col_0 + dragonruby_logo_width,
    row_1,
    0, 128, 128,
    Kernel.tick_count.to_radians.sin_r.abs * 255
  )

  args.outputs.primitives << {
    x:  col_1,
    y:  row_1,
    x2: col_1 + dragonruby_logo_width.half,
    y2: row_1 + dragonruby_logo_height,
    x3: col_1 + dragonruby_logo_width,
    y3: row_1,
    r:  0, g: 0, b: 0, a: Kernel.tick_count.to_radians.sin_r.abs * 255
  }

  args.outputs.sprites << {
    x:  col_2,
    y:  row_1,
    w:  dragonruby_logo_width,
    h:  dragonruby_logo_height,
    path: 'dragonruby.png',
    source_x:  0,
    source_y:  0,
    source_w:  dragonruby_logo_width,
    source_h:  dragonruby_logo_height.half +
               dragonruby_logo_height.half * Math.sin(Kernel.tick_count.to_radians).abs,
  }

  args.outputs.primitives << {
    x:  col_3,
    y:  row_1,
    x2: col_3 + dragonruby_logo_width.half,
    y2: row_1 + dragonruby_logo_height,
    x3: col_3 + dragonruby_logo_width,
    y3: row_1,
    path: 'dragonruby.png',
    source_x:  0,
    source_y:  0,
    source_x2: dragonruby_logo_width.half,
    source_y2: dragonruby_logo_height.half +
               dragonruby_logo_height.half * Math.sin(Kernel.tick_count.to_radians).abs,
    source_x3: dragonruby_logo_width,
    source_y3: 0
  }

  args.outputs.primitives << TriangleLogo.new(x:  col_4,
                                              y:  row_1,
                                              x2: col_4 + dragonruby_logo_width.half,
                                              y2: row_1 + dragonruby_logo_height,
                                              x3: col_4 + dragonruby_logo_width,
                                              y3: row_1,
                                              path: 'dragonruby.png',
                                              source_x:  0,
                                              source_y:  0,
                                              source_x2: dragonruby_logo_width.half,
                                              source_y2: dragonruby_logo_height.half +
                                                         dragonruby_logo_height.half * Math.sin(Kernel.tick_count.to_radians).abs,
                                              source_x3: dragonruby_logo_width,
                                              source_y3: 0)
end

def make_triangle *opts
  x, y, x2, y2, x3, y3, r, g, b, a = opts
  {
    x: x, y: y, x2: x2, y2: y2, x3: x3, y3: y3,
    r: r || 0,
    g: g || 0,
    b: b || 0,
    a: a || 255
  }
end

class TriangleLogo
  attr_sprite

  def initialize x:, y:, x2:, y2:, x3:, y3:, path:, source_x:, source_y:, source_x2:, source_y2:, source_x3:, source_y3:;
    @x         = x
    @y         = y
    @x2        = x2
    @y2        = y2
    @x3        = x3
    @y3        = y3
    @path      = path
    @source_x  = source_x
    @source_y  = source_y
    @source_x2 = source_x2
    @source_y2 = source_y2
    @source_x3 = source_x3
    @source_y3 = source_y3
  end
end

Triangles Trapezoid - main.rb link

# ./samples/07_advanced_rendering/15_triangles_trapezoid/app/main.rb
def tick args
  transform_scale = ((Kernel.tick_count / 3).sin.abs ** 5).half
  args.outputs.sprites << [
    { x:         600,
      y:         320,
      x2:        600,
      y2:        400,
      x3:        640,
      y3:        360,
      path:      "sprites/square/blue.png",
      source_x:  0,
      source_y:  0,
      source_x2: 0,
      source_y2: 80,
      source_x3: 40,
      source_y3: 40 },
    { x:         600,
      y:         400,
      x2:        680,
      y2:        (400 - 80 * transform_scale).round,
      x3:        640,
      y3:        360,
      path:      "sprites/square/blue.png",
      source_x:  0,
      source_y:  80,
      source_x2: 80,
      source_y2: 80,
      source_x3: 40,
      source_y3: 40 },
    { x:         640,
      y:         360,
      x2:        680,
      y2:        (400 - 80 * transform_scale).round,
      x3:        680,
      y3:        (320 + 80 * transform_scale).round,
      path:      "sprites/square/blue.png",
      source_x:  40,
      source_y:  40,
      source_x2: 80,
      source_y2: 80,
      source_x3: 80,
      source_y3: 0 },
    { x:         600,
      y:         320,
      x2:        640,
      y2:        360,
      x3:        680,
      y3:        (320 + 80 * transform_scale).round,
      path:      "sprites/square/blue.png",
      source_x:  0,
      source_y:  0,
      source_x2: 40,
      source_y2: 40,
      source_x3: 80,
      source_y3: 0 }
  ]
end

Camera Space World Space Simple - main.rb link

# ./samples/07_advanced_rendering/16_camera_space_world_space_simple/app/main.rb
def tick args
  # camera must have the following properties (x, y, and scale)
  args.state.camera ||= {
    x: 0,
    y: 0,
    scale: 1
  }

  args.state.camera.x += args.inputs.left_right * 10 * args.state.camera.scale
  args.state.camera.y += args.inputs.up_down * 10 * args.state.camera.scale

  # generate 500 shapes with random positions
  args.state.objects ||= 500.map do
    {
      x: -2000 + rand(4000),
      y: -2000 + rand(4000),
      w: 16,
      h: 16,
      path: 'sprites/square/blue.png'
    }
  end

  # "i" to zoom in, "o" to zoom out
  if args.inputs.keyboard.key_down.i || args.inputs.keyboard.key_down.equal_sign || args.inputs.keyboard.key_down.plus
    args.state.camera.scale += 0.1
  elsif args.inputs.keyboard.key_down.o || args.inputs.keyboard.key_down.minus
    args.state.camera.scale -= 0.1
    args.state.camera.scale = 0.1 if args.state.camera.scale < 0.1
  end

  # "zero" to reset zoom and camera
  if args.inputs.keyboard.key_down.zero
    args.state.camera.scale = 1
    args.state.camera.x = 0
    args.state.camera.y = 0
  end

  # if mouse is clicked
  if args.inputs.mouse.click
    # convert the mouse to world space and delete any objects that intersect with the mouse
    rect = Camera.to_world_space args.state.camera, args.inputs.mouse
    args.state.objects.reject! { |o| rect.intersect_rect? o }
  end

  # "r" to reset
  if args.inputs.keyboard.key_down.r
    $gtk.reset_next_tick
  end

  # define scene
  args.outputs[:scene].w = Camera::WORLD_SIZE
  args.outputs[:scene].h = Camera::WORLD_SIZE

  # render diagonals and background of scene
  args.outputs[:scene].lines << { x: 0, y: 0, x2: 1500, y2: 1500, r: 0, g: 0, b: 0, a: 255 }
  args.outputs[:scene].lines << { x: 0, y: 1500, x2: 1500, y2: 0, r: 0, g: 0, b: 0, a: 255 }
  args.outputs[:scene].solids << { x: 0, y: 0, w: 1500, h: 1500, a: 128 }

  # find all objects to render
  objects_to_render = Camera.find_all_intersect_viewport args.state.camera, args.state.objects

  # for objects that were found, convert the rect to screen coordinates and place them in scene
  args.outputs[:scene].sprites << objects_to_render.map { |o| Camera.to_screen_space args.state.camera, o }

  # render scene to screen
  args.outputs.sprites << { **Camera.viewport, path: :scene }

  # render instructions
  args.outputs.sprites << { x: 0, y: 110.from_top, w: 1280, h: 110, path: :pixel, r: 0, g: 0, b: 0, a: 128 }
  label_style = { r: 255, g: 255, b: 255, anchor_y: 0.5 }
  args.outputs.labels << { x: 30, y: 30.from_top, text: "Arrow keys to move around. I and O Keys to zoom in and zoom out (0 to reset camera, R to reset everything).", **label_style }
  args.outputs.labels << { x: 30, y: 60.from_top, text: "Click square to remove from world.", **label_style }
  args.outputs.labels << { x: 30, y: 90.from_top, text: "Mouse locationin world: #{(Camera.to_world_space args.state.camera, args.inputs.mouse).to_sf}", **label_style }
end

# helper methods to create a camera and go to and from screen space and world space
class Camera
  SCREEN_WIDTH = 1280
  SCREEN_HEIGHT = 720
  WORLD_SIZE = 1500
  WORLD_SIZE_HALF = WORLD_SIZE / 2
  OFFSET_X = (SCREEN_WIDTH - WORLD_SIZE) / 2
  OFFSET_Y = (SCREEN_HEIGHT - WORLD_SIZE) / 2

  class << self
    # given a rect in screen space, converts the rect to world space
    def to_world_space camera, rect
      rect_x = rect.x
      rect_y = rect.y
      rect_w = rect.w || 0
      rect_h = rect.h || 0
      x = (rect_x - WORLD_SIZE_HALF + camera.x * camera.scale - OFFSET_X) / camera.scale
      y = (rect_y - WORLD_SIZE_HALF + camera.y * camera.scale - OFFSET_Y) / camera.scale
      w = rect_w / camera.scale
      h = rect_h / camera.scale
      rect.merge x: x, y: y, w: w, h: h
    end

    # given a rect in world space, converts the rect to screen space
    def to_screen_space camera, rect
      rect_x = rect.x
      rect_y = rect.y
      rect_w = rect.w || 0
      rect_h = rect.h || 0
      x = rect_x * camera.scale - camera.x * camera.scale + WORLD_SIZE_HALF
      y = rect_y * camera.scale - camera.y * camera.scale + WORLD_SIZE_HALF
      w = rect_w * camera.scale
      h = rect_h * camera.scale
      rect.merge x: x, y: y, w: w, h: h
    end

    # viewport of the scene
    def viewport
      {
        x: OFFSET_X,
        y: OFFSET_Y,
        w: 1500,
        h: 1500
      }
    end

    # viewport in the context of the world
    def viewport_world camera
      to_world_space camera, viewport
    end

    # helper method to find objects within viewport
    def find_all_intersect_viewport camera, os
      Geometry.find_all_intersect_rect viewport_world(camera), os
    end
  end
end

$gtk.reset

Camera Space World Space Simple Grid Map - main.rb link

# ./samples/07_advanced_rendering/16_camera_space_world_space_simple_grid_map/app/main.rb
def tick args
  defaults args
  calc args
  render args
end

def defaults args
  tile_size = 100
  tiles_per_row = 32
  number_of_rows = 32
  number_of_tiles = tiles_per_row * number_of_rows

  # generate map tiles
  args.state.tiles ||= number_of_tiles.map_with_index do |i|
    row = i.idiv(tiles_per_row)
    col = i.mod(tiles_per_row)
    {
      x: row * tile_size,
      y: col * tile_size,
      w: tile_size,
      h: tile_size,
      path: 'sprites/square/blue.png'
    }
  end

  center_map = {
    x: tiles_per_row.idiv(2) * tile_size,
    y: number_of_rows.idiv(2) * tile_size,
    w: 1,
    h: 1
  }

  args.state.center_tile ||= args.state.tiles.find { |o| o.intersect_rect? center_map }
  args.state.selected_tile ||= args.state.center_tile

  # camera must have the following properties (x, y, and scale)
  if !args.state.camera
    args.state.camera = {
      x: 0,
      y: 0,
      scale: 1,
      target_x: 0,
      target_y: 0,
      target_scale: 1
    }

    args.state.camera.target_x = args.state.selected_tile.x + args.state.selected_tile.w.half
    args.state.camera.target_y = args.state.selected_tile.y + args.state.selected_tile.h.half
    args.state.camera.x = args.state.camera.target_x
    args.state.camera.y = args.state.camera.target_y
  end
end

def calc args
  calc_inputs args
  calc_camera args
end

def calc_inputs args
  # "i" to zoom in, "o" to zoom out
  if args.inputs.keyboard.key_down.i || args.inputs.keyboard.key_down.equal_sign || args.inputs.keyboard.key_down.plus
    args.state.camera.target_scale += 0.1 * args.state.camera.scale
  elsif args.inputs.keyboard.key_down.o || args.inputs.keyboard.key_down.minus
    args.state.camera.target_scale -= 0.1 * args.state.camera.scale
    args.state.camera.target_scale = 0.1 if args.state.camera.scale < 0.1
  end

  # "zero" to reset zoom and camera
  if args.inputs.keyboard.key_down.zero
    args.state.camera.target_scale = 1
    args.state.selected_tile = args.state.center_tile
  end

  # if mouse is clicked
  if args.inputs.mouse.click
    # convert the mouse to world space and delete any tiles that intersect with the mouse
    rect = Camera.to_world_space args.state.camera, args.inputs.mouse
    selected_tile = args.state.tiles.find { |o| rect.intersect_rect? o }
    if selected_tile
      args.state.selected_tile = selected_tile
      args.state.camera.target_scale = 1
    end
  end

  # "r" to reset
  if args.inputs.keyboard.key_down.r
    $gtk.reset_next_tick
  end
end

def calc_camera args
  args.state.camera.target_x = args.state.selected_tile.x + args.state.selected_tile.w.half
  args.state.camera.target_y = args.state.selected_tile.y + args.state.selected_tile.h.half
  dx = args.state.camera.target_x - args.state.camera.x
  dy = args.state.camera.target_y - args.state.camera.y
  ds = args.state.camera.target_scale - args.state.camera.scale
  args.state.camera.x += dx * 0.1 * args.state.camera.scale
  args.state.camera.y += dy * 0.1 * args.state.camera.scale
  args.state.camera.scale += ds * 0.1
end

def render args
  args.outputs.background_color = [0, 0, 0]

  # define scene
  args.outputs[:scene].w = Camera::WORLD_SIZE
  args.outputs[:scene].h = Camera::WORLD_SIZE
  args.outputs[:scene].background_color = [0, 0, 0, 0]

  # render diagonals and background of scene
  args.outputs[:scene].lines << { x: 0, y: 0, x2: 1500, y2: 1500, r: 0, g: 0, b: 0, a: 255 }
  args.outputs[:scene].lines << { x: 0, y: 1500, x2: 1500, y2: 0, r: 0, g: 0, b: 0, a: 255 }
  args.outputs[:scene].solids << { x: 0, y: 0, w: 1500, h: 1500, a: 128 }

  # find all tiles to render
  objects_to_render = Camera.find_all_intersect_viewport args.state.camera, args.state.tiles

  # convert mouse to world space to see if it intersects with any tiles (hover color)
  mouse_in_world = Camera.to_world_space args.state.camera, args.inputs.mouse

  # for tiles that were found, convert the rect to screen coordinates and place them in scene
  args.outputs[:scene].sprites << objects_to_render.map do |o|
    if o == args.state.selected_tile
      tile_to_render = o.merge path: 'sprites/square/green.png'
    elsif o.intersect_rect? mouse_in_world
      tile_to_render = o.merge path: 'sprites/square/orange.png'
    else
      tile_to_render = o.merge path: 'sprites/square/blue.png'
    end

    Camera.to_screen_space args.state.camera, tile_to_render
  end

  # render scene to screen
  args.outputs.sprites << { **Camera.viewport, path: :scene }

  # render instructions
  args.outputs.sprites << { x: 0, y: 110.from_top, w: 1280, h: 110, path: :pixel, r: 0, g: 0, b: 0, a: 200 }
  label_style = { r: 255, g: 255, b: 255, anchor_y: 0.5 }
  args.outputs.labels << { x: 30, y: 30.from_top, text: "I/O or +/- keys to zoom in and zoom out (0 to reset camera, R to reset everything).", **label_style }
  args.outputs.labels << { x: 30, y: 60.from_top, text: "Click to center on square.", **label_style }
  args.outputs.labels << { x: 30, y: 90.from_top, text: "Mouse location in world: #{(Camera.to_world_space args.state.camera, args.inputs.mouse).to_sf}", **label_style }
end

# helper methods to create a camera and go to and from screen space and world space
class Camera
  SCREEN_WIDTH = 1280
  SCREEN_HEIGHT = 720
  WORLD_SIZE = 1500
  WORLD_SIZE_HALF = WORLD_SIZE / 2
  OFFSET_X = (SCREEN_WIDTH - WORLD_SIZE) / 2
  OFFSET_Y = (SCREEN_HEIGHT - WORLD_SIZE) / 2

  class << self
    # given a rect in screen space, converts the rect to world space
    def to_world_space camera, rect
      rect_x = rect.x
      rect_y = rect.y
      rect_w = rect.w || 0
      rect_h = rect.h || 0
      x = (rect_x - WORLD_SIZE_HALF + camera.x * camera.scale - OFFSET_X) / camera.scale
      y = (rect_y - WORLD_SIZE_HALF + camera.y * camera.scale - OFFSET_Y) / camera.scale
      w = rect_w / camera.scale
      h = rect_h / camera.scale
      rect.merge x: x, y: y, w: w, h: h
    end

    # given a rect in world space, converts the rect to screen space
    def to_screen_space camera, rect
      rect_x = rect.x
      rect_y = rect.y
      rect_w = rect.w || 0
      rect_h = rect.h || 0
      x = rect_x * camera.scale - camera.x * camera.scale + WORLD_SIZE_HALF
      y = rect_y * camera.scale - camera.y * camera.scale + WORLD_SIZE_HALF
      w = rect_w * camera.scale
      h = rect_h * camera.scale
      rect.merge x: x, y: y, w: w, h: h
    end

    # viewport of the scene
    def viewport
      {
        x: OFFSET_X,
        y: OFFSET_Y,
        w: WORLD_SIZE,
        h: WORLD_SIZE
      }
    end

    # viewport in the context of the world
    def viewport_world camera
      to_world_space camera, viewport
    end

    # helper method to find objects within viewport
    def find_all_intersect_viewport camera, os
      Geometry.find_all_intersect_rect viewport_world(camera), os
    end
  end
end

$gtk.reset

Matrix And Triangles 2d - main.rb link

# ./samples/07_advanced_rendering/16_matrix_and_triangles_2d/app/main.rb
include MatrixFunctions

def tick args
  args.state.square_one_sprite = { x:        0,
                                   y:        0,
                                   w:        100,
                                   h:        100,
                                   path:     "sprites/square/blue.png",
                                   source_x: 0,
                                   source_y: 0,
                                   source_w: 80,
                                   source_h: 80 }

  args.state.square_two_sprite = { x:        0,
                                   y:        0,
                                   w:        100,
                                   h:        100,
                                   path:     "sprites/square/red.png",
                                   source_x: 0,
                                   source_y: 0,
                                   source_w: 80,
                                   source_h: 80 }

  args.state.square_one        = sprite_to_triangles args.state.square_one_sprite
  args.state.square_two        = sprite_to_triangles args.state.square_two_sprite
  args.state.camera.x        ||= 0
  args.state.camera.y        ||= 0
  args.state.camera.zoom     ||= 1
  args.state.camera.rotation ||= 0

  zmod = 1
  move_multiplier = 1
  dzoom = 0.01

  if Kernel.tick_count.zmod? zmod
    args.state.camera.x += args.inputs.left_right * -1 * move_multiplier
    args.state.camera.y += args.inputs.up_down * -1 * move_multiplier
  end

  if args.inputs.keyboard.i
    args.state.camera.zoom += dzoom
  elsif args.inputs.keyboard.o
    args.state.camera.zoom -= dzoom
  end

  args.state.camera.zoom = args.state.camera.zoom.clamp(0.25, 10)

  args.outputs.sprites << triangles_mat3_mul(args.state.square_one,
                                             mat3_translate(-50, -50),
                                             mat3_rotate(Kernel.tick_count),
                                             mat3_translate(0, 0),
                                             mat3_translate(args.state.camera.x, args.state.camera.y),
                                             mat3_scale(args.state.camera.zoom),
                                             mat3_translate(640, 360))

  args.outputs.sprites << triangles_mat3_mul(args.state.square_two,
                                             mat3_translate(-50, -50),
                                             mat3_rotate(Kernel.tick_count),
                                             mat3_translate(100, 100),
                                             mat3_translate(args.state.camera.x, args.state.camera.y),
                                             mat3_scale(args.state.camera.zoom),
                                             mat3_translate(640, 360))

  mouse_coord = vec3 args.inputs.mouse.x,
                     args.inputs.mouse.y,
                     1

  mouse_coord = mul mouse_coord,
                    mat3_translate(-640, -360),
                    mat3_scale(args.state.camera.zoom),
                    mat3_translate(-args.state.camera.x, -args.state.camera.y)

  args.outputs.lines  << { x: 640, y:   0, h:  720 }
  args.outputs.lines  << { x:   0, y: 360, w: 1280 }
  args.outputs.labels << { x: 30, y: 60.from_top, text: "x: #{args.state.camera.x.to_sf} y: #{args.state.camera.y.to_sf} z: #{args.state.camera.zoom.to_sf}" }
  args.outputs.labels << { x: 30, y: 90.from_top, text: "Mouse: #{mouse_coord.x.to_sf} #{mouse_coord.y.to_sf}" }
  args.outputs.labels << { x: 30,
                           y: 30.from_top,
                           text: "W,A,S,D to move. I, O to zoom." }
end

def sprite_to_triangles sprite
  [
    {
      x:         sprite.x,                          y:  sprite.y,
      x2:        sprite.x,                          y2: sprite.y + sprite.h,
      x3:        sprite.x + sprite.w,               y3: sprite.y + sprite.h,
      source_x:  sprite.source_x,                   source_y:  sprite.source_y,
      source_x2: sprite.source_x,                   source_y2: sprite.source_y + sprite.source_h,
      source_x3: sprite.source_x + sprite.source_w, source_y3: sprite.source_y + sprite.source_h,
      path:      sprite.path
    },
    {
      x:  sprite.x,                                 y:  sprite.y,
      x2: sprite.x + sprite.w,                      y2: sprite.y + sprite.h,
      x3: sprite.x + sprite.w,                      y3: sprite.y,
      source_x:  sprite.source_x,                   source_y:  sprite.source_y,
      source_x2: sprite.source_x + sprite.source_w, source_y2: sprite.source_y + sprite.source_h,
      source_x3: sprite.source_x + sprite.source_w, source_y3: sprite.source_y,
      path:      sprite.path
    }
  ]
end

def mat3_translate dx, dy
  mat3 1, 0, dx,
       0, 1, dy,
       0, 0,  1
end

def mat3_rotate angle_d
  angle_r = angle_d.to_radians
  mat3 Math.cos(angle_r), -Math.sin(angle_r), 0,
       Math.sin(angle_r),  Math.cos(angle_r), 0,
                       0,                  0, 1
end

def mat3_scale scale
  mat3 scale,     0, 0,
           0, scale, 0,
           0,     0, 1
end

def triangles_mat3_mul triangles, *matrices
  triangles.map { |triangle| triangle_mat3_mul triangle, *matrices }
end

def triangle_mat3_mul triangle, *matrices
  result = [
    (vec3 triangle.x,  triangle.y,  1),
    (vec3 triangle.x2, triangle.y2, 1),
    (vec3 triangle.x3, triangle.y3, 1)
  ].map do |coord|
    mul coord, *matrices
  end

  {
    **triangle,
    x:  result[0].x,
    y:  result[0].y,
    x2: result[1].x,
    y2: result[1].y,
    x3: result[2].x,
    y3: result[2].y,
  }
rescue Exception => e
  pretty_print triangle
  pretty_print result
  pretty_print matrices
  puts "#{matrices}"
  raise e
end

Matrix And Triangles 3d - main.rb link

# ./samples/07_advanced_rendering/16_matrix_and_triangles_3d/app/main.rb
include MatrixFunctions

def tick args
  args.outputs.labels << { x: 0,
                           y: 30.from_top,
                           text: "W,A,S,D to move. Q,E,U,O to turn, I,K for elevation.",
                           alignment_enum: 1 }

  args.grid.origin_center!

  args.state.cam_x ||= 0.00
  if args.inputs.keyboard.left
    args.state.cam_x += 0.01
  elsif args.inputs.keyboard.right
    args.state.cam_x -= 0.01
  end

  args.state.cam_y ||= 0.00
  if args.inputs.keyboard.i
    args.state.cam_y += 0.01
  elsif args.inputs.keyboard.k
    args.state.cam_y -= 0.01
  end

  args.state.cam_z ||= 6.5
  if args.inputs.keyboard.s
    args.state.cam_z += 0.1
  elsif args.inputs.keyboard.w
    args.state.cam_z -= 0.1
  end

  args.state.cam_angle_y ||= 0
  if args.inputs.keyboard.q
    args.state.cam_angle_y += 0.25
  elsif args.inputs.keyboard.e
    args.state.cam_angle_y -= 0.25
  end

  args.state.cam_angle_x ||= 0
  if args.inputs.keyboard.u
    args.state.cam_angle_x += 0.1
  elsif args.inputs.keyboard.o
    args.state.cam_angle_x -= 0.1
  end

  # model A
  args.state.a = [
    [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
    [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
  ]

  # model to world
  args.state.a_world = mul_world args,
                                 args.state.a,
                                 (translate -0.25, -0.25, 0),
                                 (translate  0, 0, 0.25),
                                 (rotate_x Kernel.tick_count)

  args.state.a_camera = mul_cam args, args.state.a_world
  args.state.a_projected = mul_perspective args, args.state.a_camera
  render_projection args, args.state.a_projected

  # model B
  args.state.b = [
    [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
    [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
  ]

  # model to world
  args.state.b_world = mul_world args,
                                 args.state.b,
                                 (translate -0.25, -0.25, 0),
                                 (translate  0, 0, -0.25),
                                 (rotate_x Kernel.tick_count)

  args.state.b_camera = mul_cam args, args.state.b_world
  args.state.b_projected = mul_perspective args, args.state.b_camera
  render_projection args, args.state.b_projected

  # model C
  args.state.c = [
    [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
    [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
  ]

  # model to world
  args.state.c_world = mul_world args,
                                 args.state.c,
                                 (translate -0.25, -0.25, 0),
                                 (rotate_y 90),
                                 (translate -0.25,  0, 0),
                                 (rotate_x Kernel.tick_count)

  args.state.c_camera = mul_cam args, args.state.c_world
  args.state.c_projected = mul_perspective args, args.state.c_camera
  render_projection args, args.state.c_projected

  # model D
  args.state.d = [
    [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
    [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
  ]

  # model to world
  args.state.d_world = mul_world args,
                                 args.state.d,
                                 (translate -0.25, -0.25, 0),
                                 (rotate_y 90),
                                 (translate  0.25,  0, 0),
                                 (rotate_x Kernel.tick_count)

  args.state.d_camera = mul_cam args, args.state.d_world
  args.state.d_projected = mul_perspective args, args.state.d_camera
  render_projection args, args.state.d_projected

  # model E
  args.state.e = [
    [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
    [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
  ]

  # model to world
  args.state.e_world = mul_world args,
                                 args.state.e,
                                 (translate -0.25, -0.25, 0),
                                 (rotate_x 90),
                                 (translate  0,  0.25, 0),
                                 (rotate_x Kernel.tick_count)

  args.state.e_camera = mul_cam args, args.state.e_world
  args.state.e_projected = mul_perspective args, args.state.e_camera
  render_projection args, args.state.e_projected

  # model E
  args.state.f = [
    [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
    [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
  ]

  # model to world
  args.state.f_world = mul_world args,
                                 args.state.f,
                                 (translate -0.25, -0.25, 0),
                                 (rotate_x 90),
                                 (translate  0,  -0.25, 0),
                                 (rotate_x Kernel.tick_count)

  args.state.f_camera = mul_cam args, args.state.f_world
  args.state.f_projected = mul_perspective args, args.state.f_camera
  render_projection args, args.state.f_projected

  # render_debug args, args.state.a, args.state.a_transform, args.state.a_projected
  # args.outputs.labels << { x: -630, y:  10.from_top,  text: "x:         #{args.state.cam_x.to_sf} -> #{( args.state.cam_x * 1000 ).to_sf}" }
  # args.outputs.labels << { x: -630, y:  30.from_top,  text: "y:         #{args.state.cam_y.to_sf} -> #{( args.state.cam_y * 1000 ).to_sf}" }
  # args.outputs.labels << { x: -630, y:  50.from_top,  text: "z:         #{args.state.cam_z.fdiv(10).to_sf} -> #{( args.state.cam_z * 100 ).to_sf}" }
end

def mul_world args, model, *mul_def
  model.map do |vecs|
    vecs.map do |vec|
      mul vec,
          *mul_def
    end
  end
end

def mul_cam args, world_vecs
  world_vecs.map do |vecs|
    vecs.map do |vec|
      mul vec,
          (translate -args.state.cam_x, args.state.cam_y, -args.state.cam_z),
          (rotate_y args.state.cam_angle_y),
          (rotate_x args.state.cam_angle_x)
    end
  end
end

def mul_perspective args, camera_vecs
  camera_vecs.map do |vecs|
    vecs.map do |vec|
      perspective vec
    end
  end
end

def render_debug args, model, transform, projected
  args.outputs.labels << { x: -630, y:  10.from_top,  text: "model:     #{vecs_to_s model[0]}" }
  args.outputs.labels << { x: -630, y:  30.from_top,  text: "           #{vecs_to_s model[1]}" }
  args.outputs.labels << { x: -630, y:  50.from_top,  text: "transform: #{vecs_to_s transform[0]}" }
  args.outputs.labels << { x: -630, y:  70.from_top,  text: "           #{vecs_to_s transform[1]}" }
  args.outputs.labels << { x: -630, y:  90.from_top,  text: "projected: #{vecs_to_s projected[0]}" }
  args.outputs.labels << { x: -630, y: 110.from_top,  text: "           #{vecs_to_s projected[1]}" }
end

def render_projection args, projection
  p0 = projection[0]
  args.outputs.sprites << {
    x:  p0[0].x,   y: p0[0].y,
    x2: p0[1].x,  y2: p0[1].y,
    x3: p0[2].x,  y3: p0[2].y,
    source_x:   0, source_y:   0,
    source_x2: 80, source_y2:  0,
    source_x3:  0, source_y3: 80,
    a: 40,
    # r: 128, g: 128, b: 128,
    path: 'sprites/square/blue.png'
  }

  p1 = projection[1]
  args.outputs.sprites << {
    x:  p1[0].x,   y: p1[0].y,
    x2: p1[1].x,  y2: p1[1].y,
    x3: p1[2].x,  y3: p1[2].y,
    source_x:  80, source_y:   0,
    source_x2: 80, source_y2: 80,
    source_x3:  0, source_y3: 80,
    a: 40,
    # r: 128, g: 128, b: 128,
    path: 'sprites/square/blue.png'
  }
end

def perspective vec
  left   = -1.0
  right  =  1.0
  bottom = -1.0
  top    =  1.0
  near   =  300.0
  far    =  1000.0
  sx = 2 * near / (right - left)
  sy = 2 * near / (top - bottom)
  c2 = - (far + near) / (far - near)
  c1 = 2 * near * far / (near - far)
  tx = -near * (left + right) / (right - left)
  ty = -near * (bottom + top) / (top - bottom)

  p = mat4 sx, 0, 0, tx,
           0, sy, 0, ty,
           0, 0, c2, c1,
           0, 0, -1, 0

  r = mul vec, p
  r.x *= r.z / r.w / 100
  r.y *= r.z / r.w / 100
  r
end

def mat_scale scale
  mat4 scale,     0,     0,   0,
           0, scale,     0,   0,
           0,     0, scale,   0,
           0,     0,     0,   1
end

def rotate_y angle_d
  cos_t = Math.cos angle_d.to_radians
  sin_t = Math.sin angle_d.to_radians
  (mat4  cos_t,  0, sin_t, 0,
         0,      1, 0,     0,
         -sin_t, 0, cos_t, 0,
         0,      0, 0,     1)
end

def rotate_z angle_d
  cos_t = Math.cos angle_d.to_radians
  sin_t = Math.sin angle_d.to_radians
  (mat4 cos_t, -sin_t, 0, 0,
        sin_t,  cos_t, 0, 0,
        0,      0,     1, 0,
        0,      0,     0, 1)
end

def translate dx, dy, dz
  mat4 1, 0, 0, dx,
       0, 1, 0, dy,
       0, 0, 1, dz,
       0, 0, 0,  1
end


def rotate_x angle_d
  cos_t = Math.cos angle_d.to_radians
  sin_t = Math.sin angle_d.to_radians
  (mat4  1,     0,      0, 0,
         0, cos_t, -sin_t, 0,
         0, sin_t,  cos_t, 0,
         0,     0,      0, 1)
end

def vecs_to_s vecs
  vecs.map do |vec|
    "[#{vec.x.to_sf} #{vec.y.to_sf} #{vec.z.to_sf}]"
  end.join " "
end

Matrix Camera Space World Space - main.rb link

# ./samples/07_advanced_rendering/16_matrix_camera_space_world_space/app/main.rb
# sample app shows how to translate between screen and world coordinates using matrix multiplication
class Game
  attr_gtk

  def tick
    defaults
    input
    calc
    render
  end

  def defaults
    return if Kernel.tick_count != 0

    # define the size of the world
    state.world_size = 1280

    # initialize the camera
    state.camera = {
      x: 0,
      y: 0,
      zoom: 1
    }

    # initialize entities: place entities randomly in the world
    state.entities = 200.map do
      {
        x: (rand * state.world_size - 100).to_i * (rand > 0.5 ? 1 : -1),
        y: (rand * state.world_size - 100).to_i * (rand > 0.5 ? 1 : -1),
        w: 32,
        h: 32,
        angle: 0,
        path: "sprites/square/blue.png",
        rotation_speed: rand * 5
      }
    end

    # backdrop for the world
    state.backdrop = { x: -state.world_size,
                       y: -state.world_size,
                       w: state.world_size * 2,
                       h: state.world_size * 2,
                       r: 200,
                       g: 100,
                       b: 0,
                       a: 128,
                       path: :pixel }

    # rect representing the screen
    state.screen_rect = { x: 0, y: 0, w: 1280, h: 720 }

    # update the camera matricies (initial state)
    update_matricies!
  end

  # if the camera is ever changed, recompute the matricies that are used
  # to translate between screen and world coordinates. we want to cache
  # the resolved matrix for speed
  def update_matricies!
    # camera space is defined with three matricies
    # every entity is:
    # - offset by the location of the camera
    # - scaled
    # - then centered on the screen
    state.to_camera_space_matrix = MatrixFunctions.mul(mat3_translate(state.camera.x, state.camera.y),
                                                       mat3_scale(state.camera.zoom),
                                                       mat3_translate(640, 360))

    # world space is defined based off the camera matricies but inverted:
    # every entity is:
    # - uncentered from the screen
    # - unscaled
    # - offset by the location of the camera in the opposite direction
    state.to_world_space_matrix = MatrixFunctions.mul(mat3_translate(-640, -360),
                                                      mat3_scale(1.0 / state.camera.zoom),
                                                      mat3_translate(-state.camera.x, -state.camera.y))

    # the viewport is computed by taking the screen rect and moving it into world space.
    # what entities get rendered is based off of the viewport
    state.viewport = rect_mul_matrix(state.screen_rect, state.to_world_space_matrix)
  end

  def input
    # if the camera is changed, invalidate/recompute the translation matricies
    should_update_matricies = false

    # + and - keys zoom in and out
    if inputs.keyboard.equal_sign || inputs.keyboard.plus || inputs.mouse.wheel && inputs.mouse.wheel.y > 0
      state.camera.zoom += 0.01 * state.camera.zoom
      should_update_matricies = true
    elsif inputs.keyboard.minus || inputs.mouse.wheel && inputs.mouse.wheel.y < 0
      state.camera.zoom -= 0.01 * state.camera.zoom
      should_update_matricies = true
    end

    # clamp the zoom to a minimum of 0.25
    if state.camera.zoom < 0.25
      state.camera.zoom = 0.25
      should_update_matricies = true
    end

    # left and right keys move the camera left and right
    if inputs.left_right != 0
      state.camera.x += -1 * (inputs.left_right * 10) * state.camera.zoom
      should_update_matricies = true
    end

    # up and down keys move the camera up and down
    if inputs.up_down != 0
      state.camera.y += -1 * (inputs.up_down * 10) * state.camera.zoom
      should_update_matricies = true
    end

    # reset the camera to the default position
    if inputs.keyboard.key_down.zero
      state.camera.x = 0
      state.camera.y = 0
      state.camera.zoom = 1
      should_update_matricies = true
    end

    # if the update matricies flag is set, recompute the matricies
    update_matricies! if should_update_matricies
  end

  def calc
    # rotate all the entities by their rotation speed
    # and reset their hovered state
    state.entities.each do |entity|
      entity.hovered = false
      entity.angle += entity.rotation_speed
    end

    # find all the entities that are hovered by the mouse and update their state back to hovered
    mouse_in_world = rect_to_world_coordinates inputs.mouse.rect
    hovered_entities = geometry.find_all_intersect_rect mouse_in_world, state.entities
    hovered_entities.each { |entity| entity.hovered = true }
  end

  def render
    # create a render target to represent the camera's viewport
    outputs[:scene].w = state.world_size
    outputs[:scene].h = state.world_size

    # render the backdrop
    outputs[:scene].primitives << rect_to_screen_coordinates(state.backdrop)

    # get all entities that are within the camera's viewport
    entities_to_render = geometry.find_all_intersect_rect state.viewport, state.entities

    # render all the entities within the viewport
    outputs[:scene].primitives << entities_to_render.map do |entity|
      r = rect_to_screen_coordinates entity

      # change the color of the entity if it's hovered
      r.merge!(path: "sprites/square/red.png") if entity.hovered

      r
    end

    # render the camera's viewport
    outputs.sprites << {
      x: 0,
      y: 0,
      w: state.world_size,
      h: state.world_size,
      path: :scene
    }

    # show a label that shows the mouse's screen and world coordinates
    outputs.labels << { x: 30, y: 30.from_top, text: "#{gtk.current_framerate.to_sf}" }

    mouse_in_world = rect_to_world_coordinates inputs.mouse.rect

    outputs.labels << {
      x: 30,
      y: 55.from_top,
      text: "Screen Coordinates: #{inputs.mouse.x}, #{inputs.mouse.y}",
    }

    outputs.labels << {
      x: 30,
      y: 80.from_top,
      text: "World Coordinates: #{mouse_in_world.x.to_sf}, #{mouse_in_world.y.to_sf}",
    }
  end

  def rect_to_screen_coordinates rect
    rect_mul_matrix rect, state.to_camera_space_matrix
  end

  def rect_to_world_coordinates rect
    rect_mul_matrix rect, state.to_world_space_matrix
  end

  def rect_mul_matrix rect, matrix
    # the bottom left and top right corners of the rect
    # are multiplied by the matrix to get the new coordinates
    bottom_left = MatrixFunctions.mul (MatrixFunctions.vec3 rect.x, rect.y, 1), matrix
    top_right   = MatrixFunctions.mul (MatrixFunctions.vec3 rect.x + rect.w, rect.y + rect.h, 1), matrix

    # with the points of the rect recomputed, reconstruct the rect
    rect.merge x: bottom_left.x,
               y: bottom_left.y,
               w: top_right.x - bottom_left.x,
               h: top_right.y - bottom_left.y
  end

  # this is the definition of how to move a point in 2d space using a matrix
  def mat3_translate x, y
    MatrixFunctions.mat3 1, 0, x,
                         0, 1, y,
                         0, 0, 1
  end

  # this is the definition of how to scale a point in 2d space using a matrix
  def mat3_scale scale
    MatrixFunctions.mat3 scale, 0, 0,
                         0, scale, 0,
                         0,     0, 1
  end
end

$game = Game.new

def tick args
  $game.args = args
  $game.tick
end

$gtk.reset

Matrix Cubeworld - main.rb link

# ./samples/07_advanced_rendering/16_matrix_cubeworld/app/main.rb
require 'app/modeling-api.rb'

include MatrixFunctions

def tick args
  args.outputs.labels << { x: 0,
                           y: 30.from_top,
                           text: "W,A,S,D to move. Mouse to look.",
                           alignment_enum: 1 }

  args.grid.origin_center!

  args.state.cam_y ||= 0.00
  if args.inputs.keyboard.i
    args.state.cam_y += 0.01
  elsif args.inputs.keyboard.k
    args.state.cam_y -= 0.01
  end

  args.state.cam_angle_y ||= 0
  if args.inputs.keyboard.q
    args.state.cam_angle_y += 0.25
  elsif args.inputs.keyboard.e
    args.state.cam_angle_y -= 0.25
  end

  args.state.cam_angle_x ||= 0
  if args.inputs.keyboard.u
    args.state.cam_angle_x += 0.1
  elsif args.inputs.keyboard.o
    args.state.cam_angle_x -= 0.1
  end

  if args.inputs.mouse.has_focus
    y_change_rate = (args.inputs.mouse.x / 640) ** 2
    if args.inputs.mouse.x < 0
      args.state.cam_angle_y -= 0.8 * y_change_rate
    else
      args.state.cam_angle_y += 0.8 * y_change_rate
    end

    x_change_rate = (args.inputs.mouse.y / 360) ** 2
    if args.inputs.mouse.y < 0
      args.state.cam_angle_x += 0.8 * x_change_rate
    else
      args.state.cam_angle_x -= 0.8 * x_change_rate
    end
  end

  args.state.cam_z ||= 6.4
  if args.inputs.keyboard.up
    point_1 = { x: 0, y: 0.02 }
    point_r = args.geometry.rotate_point point_1, args.state.cam_angle_y
    args.state.cam_x -= point_r.x
    args.state.cam_z -= point_r.y
  elsif args.inputs.keyboard.down
    point_1 = { x: 0, y: -0.02 }
    point_r = args.geometry.rotate_point point_1, args.state.cam_angle_y
    args.state.cam_x -= point_r.x
    args.state.cam_z -= point_r.y
  end

  args.state.cam_x ||= 0.00
  if args.inputs.keyboard.right
    point_1 = { x: -0.02, y: 0 }
    point_r = args.geometry.rotate_point point_1, args.state.cam_angle_y
    args.state.cam_x -= point_r.x
    args.state.cam_z -= point_r.y
  elsif args.inputs.keyboard.left
    point_1 = { x:  0.02, y: 0 }
    point_r = args.geometry.rotate_point point_1, args.state.cam_angle_y
    args.state.cam_x -= point_r.x
    args.state.cam_z -= point_r.y
  end


  if args.inputs.keyboard.key_down.r || args.inputs.keyboard.key_down.zero
    args.state.cam_x = 0.00
    args.state.cam_y = 0.00
    args.state.cam_z = 1.00
    args.state.cam_angle_y = 0
    args.state.cam_angle_x = 0
  end

  if !args.state.models
    args.state.models = []
    25.times do
      args.state.models.concat new_random_cube
    end
  end

  args.state.models.each do |m|
    render_triangles args, m
  end

  args.outputs.lines << { x:   0, y: -50, h: 100, a: 80 }
  args.outputs.lines << { x: -50, y:   0, w: 100, a: 80 }
end

def mul_triangles model, *mul_def
  combined = mul mul_def
  model.map do |vecs|
    vecs.map do |vec|
      mul vec, *combined
    end
  end
end

def mul_cam args, world_vecs
  mul_triangles world_vecs,
                (translate -args.state.cam_x, -args.state.cam_y, -args.state.cam_z),
                (rotate_y args.state.cam_angle_y),
                (rotate_x args.state.cam_angle_x)
end

def mul_perspective camera_vecs
  camera_vecs.map do |vecs|
    r = vecs.map do |vec|
      perspective vec
    end

    r if r[0] && r[1] && r[2]
  end.reject_nil
end

def render_debug args, model, transform, projected
  args.outputs.labels << { x: -630, y:  10.from_top,  text: "model:     #{vecs_to_s model[0]}" }
  args.outputs.labels << { x: -630, y:  30.from_top,  text: "           #{vecs_to_s model[1]}" }
  args.outputs.labels << { x: -630, y:  50.from_top,  text: "transform: #{vecs_to_s transform[0]}" }
  args.outputs.labels << { x: -630, y:  70.from_top,  text: "           #{vecs_to_s transform[1]}" }
  args.outputs.labels << { x: -630, y:  90.from_top,  text: "projected: #{vecs_to_s projected[0]}" }
  args.outputs.labels << { x: -630, y: 110.from_top,  text: "           #{vecs_to_s projected[1]}" }
end

def render_triangles args, triangles
  camera_space = mul_cam args, triangles
  projection = mul_perspective camera_space

  args.outputs.sprites << projection.map_with_index do |i, index|
    if i
      {
        x:  i[0].x,   y: i[0].y,
        x2: i[1].x,  y2: i[1].y,
        x3: i[2].x,  y3: i[2].y,
        source_x:   0, source_y:   0,
        source_x2: 80, source_y2:  0,
        source_x3:  0, source_y3: 80,
        r: 128, g: 128, b: 128,
        a: 80 + 128 * 1 / (index + 1),
        path: :pixel
      }
    end
  end
end

def perspective vec
  left   =  100.0
  right  = -100.0
  bottom =  100.0
  top    = -100.0
  near   =  3000.0
  far    =  8000.0
  sx = 2 * near / (right - left)
  sy = 2 * near / (top - bottom)
  c2 = - (far + near) / (far - near)
  c1 = 2 * near * far / (near - far)
  tx = -near * (left + right) / (right - left)
  ty = -near * (bottom + top) / (top - bottom)

  p = mat4 sx, 0, 0, tx,
           0, sy, 0, ty,
           0, 0, c2, c1,
           0, 0, -1, 0

  r = mul vec, p
  return nil if r.w < 0
  r.x *= r.z / r.w / 100
  r.y *= r.z / r.w / 100
  r
end

def mat_scale scale
  mat4 scale,     0,     0,   0,
           0, scale,     0,   0,
           0,     0, scale,   0,
           0,     0,     0,   1
end

def rotate_y angle_d
  cos_t = Math.cos angle_d.to_radians
  sin_t = Math.sin angle_d.to_radians
  (mat4  cos_t,  0, sin_t, 0,
         0,      1, 0,     0,
         -sin_t, 0, cos_t, 0,
         0,      0, 0,     1)
end

def rotate_z angle_d
  cos_t = Math.cos angle_d.to_radians
  sin_t = Math.sin angle_d.to_radians
  (mat4 cos_t, -sin_t, 0, 0,
        sin_t,  cos_t, 0, 0,
        0,      0,     1, 0,
        0,      0,     0, 1)
end

def translate dx, dy, dz
  mat4 1, 0, 0, dx,
       0, 1, 0, dy,
       0, 0, 1, dz,
       0, 0, 0,  1
end


def rotate_x angle_d
  cos_t = Math.cos angle_d.to_radians
  sin_t = Math.sin angle_d.to_radians
  (mat4  1,     0,      0, 0,
         0, cos_t, -sin_t, 0,
         0, sin_t,  cos_t, 0,
         0,     0,      0, 1)
end

def vecs_to_s vecs
  vecs.map do |vec|
    "[#{vec.x.to_sf} #{vec.y.to_sf} #{vec.z.to_sf}]"
  end.join " "
end

def new_random_cube
  cube_w = rand * 0.2 + 0.1
  cube_h = rand * 0.2 + 0.1
  randx = rand * 2.0 * [1, -1].sample
  randy = rand * 2.0
  randz = rand * 5   * [1, -1].sample

  cube = [
    square do
      scale x: cube_w, y: cube_h
      translate x: -cube_w / 2, y: -cube_h / 2
      rotate_x 90
      translate y: -cube_h / 2
      translate x: randx, y: randy, z: randz
    end,
    square do
      scale x: cube_w, y: cube_h
      translate x: -cube_w / 2, y: -cube_h / 2
      rotate_x 90
      translate y:  cube_h / 2
      translate x: randx, y: randy, z: randz
    end,
    square do
      scale x: cube_h, y: cube_h
      translate x: -cube_h / 2, y: -cube_h / 2
      rotate_y 90
      translate x: -cube_w / 2
      translate x: randx, y: randy, z: randz
    end,
    square do
      scale x: cube_h, y: cube_h
      translate x: -cube_h / 2, y: -cube_h / 2
      rotate_y 90
      translate x:  cube_w / 2
      translate x: randx, y: randy, z: randz
    end,
    square do
      scale x: cube_w, y: cube_h
      translate x: -cube_w / 2, y: -cube_h / 2
      translate z: -cube_h / 2
      translate x: randx, y: randy, z: randz
    end,
    square do
      scale x: cube_w, y: cube_h
      translate x: -cube_w / 2, y: -cube_h / 2
      translate z:  cube_h / 2
      translate x: randx, y: randy, z: randz
    end
  ]

  cube
end

$gtk.reset

Matrix Cubeworld - modeling-api.rb link

# ./samples/07_advanced_rendering/16_matrix_cubeworld/app/modeling-api.rb
class ModelingApi
  attr :matricies

  def initialize
    @matricies = []
  end

  def scale x: 1, y: 1, z: 1
    @matricies << scale_matrix(x: x, y: y, z: z)
    if block_given?
      yield
      @matricies << scale_matrix(x: -x, y: -y, z: -z)
    end
  end

  def translate x: 0, y: 0, z: 0
    @matricies << translate_matrix(x: x, y: y, z: z)
    if block_given?
      yield
      @matricies << translate_matrix(x: -x, y: -y, z: -z)
    end
  end

  def rotate_x x
    @matricies << rotate_x_matrix(x)
    if block_given?
      yield
      @matricies << rotate_x_matrix(-x)
    end
  end

  def rotate_y y
    @matricies << rotate_y_matrix(y)
    if block_given?
      yield
      @matricies << rotate_y_matrix(-y)
    end
  end

  def rotate_z z
    @matricies << rotate_z_matrix(z)
    if block_given?
      yield
      @matricies << rotate_z_matrix(-z)
    end
  end

  def scale_matrix x:, y:, z:;
    mat4 x, 0, 0, 0,
         0, y, 0, 0,
         0, 0, z, 0,
         0, 0, 0, 1
  end

  def translate_matrix x:, y:, z:;
    mat4 1, 0, 0, x,
         0, 1, 0, y,
         0, 0, 1, z,
         0, 0, 0, 1
  end

  def rotate_y_matrix angle_d
    cos_t = Math.cos angle_d.to_radians
    sin_t = Math.sin angle_d.to_radians
    (mat4  cos_t,  0, sin_t, 0,
           0,      1, 0,     0,
           -sin_t, 0, cos_t, 0,
           0,      0, 0,     1)
  end

  def rotate_z_matrix angle_d
    cos_t = Math.cos angle_d.to_radians
    sin_t = Math.sin angle_d.to_radians
    (mat4 cos_t, -sin_t, 0, 0,
          sin_t,  cos_t, 0, 0,
          0,      0,     1, 0,
          0,      0,     0, 1)
  end

  def rotate_x_matrix angle_d
    cos_t = Math.cos angle_d.to_radians
    sin_t = Math.sin angle_d.to_radians
    (mat4  1,     0,      0, 0,
           0, cos_t, -sin_t, 0,
           0, sin_t,  cos_t, 0,
           0,     0,      0, 1)
  end

  def __mul_triangles__ model, *mul_def
    model.map do |vecs|
      vecs.map do |vec|
        mul vec,
            *mul_def
      end
    end
  end
end

def square &block
  square_verticies = [
    [vec4(0, 0, 0, 1),   vec4(1.0, 0, 0, 1),   vec4(0, 1.0, 0, 1)],
    [vec4(1.0, 0, 0, 1), vec4(1.0, 1.0, 0, 1), vec4(0, 1.0, 0, 1)]
  ]

  m = ModelingApi.new
  m.instance_eval &block if block
  m.__mul_triangles__ square_verticies, *m.matricies
end

Override Core Rendering - main.rb link

# ./samples/07_advanced_rendering/17_override_core_rendering/app/main.rb
class GTK::Runtime
  # You can completely override how DR renders by defining this method
  # It is strongly recommend that you do not do this unless you know what you're doing.
  def primitives pass
    # pass.solids.each { |o| draw_solid o }
    # pass.static_solids.each { |o| draw_solid o }
    # pass.sprites.each { |o| draw_sprite o }
    # pass.static_sprites.each { |o| draw_sprite o }
    # pass.primitives.each { |o| draw_primitive o }
    # pass.static_primitives.each { |o| draw_primitive o }
    pass.labels.each { |o| draw_label o }
    pass.static_labels.each { |o| draw_label o }
    # pass.lines.each { |o| draw_line o }
    # pass.static_lines.each { |o| draw_line o }
    # pass.borders.each { |o| draw_border o }
    # pass.static_borders.each { |o| draw_border o }

    # if !self.production
    #   pass.debug.each { |o| draw_primitive o }
    #   pass.static_debug.each { |o| draw_primitive o }
    # end

    # pass.reserved.each { |o| draw_primitive o }
    # pass.static_reserved.each { |o| draw_primitive o }
  end
end

def tick args
  args.outputs.labels << { x: 30, y: 30, text: "primitives function defined, only labels rendered" }
  args.outputs.sprites << { x: 100, y: 100, w: 100, h: 100, path: "dragonruby.png" }
end

Layouts - main.rb link

# ./samples/07_advanced_rendering/18_layouts/app/main.rb
def tick args
  args.outputs.solids << args.layout.rect(row: 0,
                                          col: 0,
                                          w: 24,
                                          h: 12,
                                          include_row_gutter: true,
                                          include_col_gutter: true).merge(b: 255, a: 80)
  render_row_examples args
  render_column_examples args
  render_max_width_max_height_examples args
  render_points_with_anchored_label_examples args
  render_centered_rect_examples args
  render_rect_group_examples args
end

def render_row_examples args
  # rows (light blue)
  args.outputs.labels << args.layout.rect(row: 1, col: 6 + 3).merge(text: "row examples", anchor_x: 0.5, anchor_y: 0.5)
  4.map_with_index do |row|
    args.outputs.solids << args.layout.rect(row: row, col: 6, w: 1, h: 1).merge(**light_blue)
  end

  2.map_with_index do |row|
    args.outputs.solids << args.layout.rect(row: row * 2, col: 6 + 1, w: 1, h: 2).merge(**light_blue)
  end

  4.map_with_index do |row|
    args.outputs.solids << args.layout.rect(row: row, col: 6 + 2, w: 2, h: 1).merge(**light_blue)
  end

  2.map_with_index do |row|
    args.outputs.solids << args.layout.rect(row: row * 2, col: 6 + 4, w: 2, h: 2).merge(**light_blue)
  end
end

def render_column_examples args
  # columns (yellow)
  yellow = { r: 255, g: 255, b: 128 }
  args.outputs.labels << args.layout.rect(row: 1, col: 12 + 3).merge(text: "column examples", anchor_x: 0.5, anchor_y: 0.5)
  6.times do |col|
    args.outputs.solids << args.layout.rect(row: 0, col: 12 + col, w: 1, h: 1).merge(**yellow)
  end

  3.times do |col|
    args.outputs.solids << args.layout.rect(row: 1, col: 12 + col * 2, w: 2, h: 1).merge(**yellow)
  end

  6.times do |col|
    args.outputs.solids << args.layout.rect(row: 2, col: 12 + col, w: 1, h: 2).merge(**yellow)
  end
end

def render_max_width_max_height_examples args
  # max width/height baseline (transparent green)
  args.outputs.labels << args.layout.rect(row: 4, col: 12).merge(text: "max width/height examples", anchor_x: 0.5, anchor_y: 0.5)
  args.outputs.solids << args.layout.rect(row: 4, col: 0, w: 24, h: 2).merge(a: 64, **green)

  # max height
  args.outputs.solids << args.layout.rect(row: 4, col: 0, w: 24, h: 2, max_height: 1).merge(a: 64, **green)

  # max width
  args.outputs.solids << args.layout.rect(row: 4, col: 0, w: 24, h: 2, max_width: 12).merge(a: 64, **green)
end

def render_points_with_anchored_label_examples args
  # labels relative to rects
  label_color = { r: 0, g: 0, b: 0 }

  # labels realtive to point, achored at 0.0, 0.0
  args.outputs.borders << args.layout.rect(row: 6, col: 3, w: 6, h: 5)
  args.outputs.labels << args.layout.rect(row: 6, col: 3, w: 6, h: 1).center.merge(text: "layout.point anchored to 0.0, 0.0", anchor_x: 0.5, anchor_y: 0.5, size_px: 15)
  grey = { r: 128, g: 128, b: 128 }
  args.outputs.solids << args.layout.rect(row: 7, col: 4.5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 7, col: 4.5, row_anchor: 1.0, col_anchor: 0.0).merge(text: "[x]", anchor_x: 0.5, anchor_y: 0.5, **label_color)

  args.outputs.solids << args.layout.rect(row: 7, col: 5.5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 7, col: 5.5, row_anchor: 1.0, col_anchor: 0.5).merge(text: "[x]", anchor_x: 0.5, anchor_y: 0.5, **label_color)

  args.outputs.solids << args.layout.rect(row: 7, col: 6.5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 7, col: 6.5, row_anchor: 1.0, col_anchor: 1.0).merge(text: "[x]", anchor_x: 0.5, anchor_y: 0.5, **label_color)

  args.outputs.solids << args.layout.rect(row: 8, col: 4.5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 8, col: 4.5, row_anchor: 0.5, col_anchor: 0.0).merge(text: "[x]", anchor_x: 0.5, anchor_y: 0.5, **label_color)

  args.outputs.solids << args.layout.rect(row: 8, col: 5.5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 8, col: 5.5, row_anchor: 0.5, col_anchor: 0.5).merge(text: "[x]", anchor_x: 0.5, anchor_y: 0.5, **label_color)

  args.outputs.solids << args.layout.rect(row: 8, col: 6.5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 8, col: 6.5, row_anchor: 0.5, col_anchor: 1.0).merge(text: "[x]", anchor_x: 0.5, anchor_y: 0.5, **label_color)

  args.outputs.solids << args.layout.rect(row: 9, col: 4.5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 9, col: 4.5, row_anchor: 0.0, col_anchor: 0.0).merge(text: "[x]", anchor_x: 0.5, anchor_y: 0.5, **label_color)

  args.outputs.solids << args.layout.rect(row: 9, col: 5.5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 9, col: 5.5, row_anchor: 0.0, col_anchor: 0.5).merge(text: "[x]", anchor_x: 0.5, anchor_y: 0.5, **label_color)

  args.outputs.solids << args.layout.rect(row: 9, col: 6.5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 9, col: 6.5, row_anchor: 0.0, col_anchor: 1.0).merge(text: "[x]", anchor_x: 0.5, anchor_y: 0.5, **label_color)
end

def render_centered_rect_examples args
  # centering rects
  args.outputs.borders << args.layout.rect(row: 6, col: 9, w: 6, h: 5)
  args.outputs.labels << args.layout.rect(row: 6, col: 9, w: 6, h: 1).center.merge(text: "layout.rect centered inside another rect", anchor_x: 0.5, anchor_y: 0.5, size_px: 15)
  outer_rect = args.layout.rect(row: 7, col: 10.5, w: 3, h: 3)

  # render outer rect
  args.outputs.solids << outer_rect.merge(**light_blue)

  # # center a yellow rect with w and h of two
  args.outputs.solids << args.layout.rect_center(
    args.layout.rect(w: 1, h: 5), # inner rect
    outer_rect, # outer rect
  ).merge(**yellow)

  # # center a black rect with w three h of one
  args.outputs.solids << args.layout.rect_center(
    args.layout.rect(w: 5, h: 1), # inner rect
    outer_rect, # outer rect
  )
end

def render_rect_group_examples args
  args.outputs.labels << args.layout.rect(row: 6, col: 15, w: 6, h: 1).center.merge(text: "layout.rect_group usage", anchor_x: 0.5, anchor_y: 0.5, size_px: 15)
  args.outputs.borders << args.layout.rect(row: 6, col: 15, w: 6, h: 5)

  horizontal_markers = [
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
  ]

  args.outputs.solids << args.layout.rect_group(row: 7,
                                                col: 15,
                                                dcol: 1,
                                                w: 1,
                                                h: 1,
                                                group: horizontal_markers)

  vertical_markers = [
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 }
  ]

  args.outputs.solids << args.layout.rect_group(row: 7,
                                                col: 15,
                                                drow: 1,
                                                w: 1,
                                                h: 1,
                                                group: vertical_markers)

  colors = [
    { r:   0, g:   0, b:   0 },
    { r:  50, g:  50, b:  50 },
    { r: 100, g: 100, b: 100 },
    { r: 150, g: 150, b: 150 },
    { r: 200, g: 200, b: 200 },
    { r: 250, g: 250, b: 250 },
  ]

  args.outputs.solids << args.layout.rect_group(row: 8,
                                                col: 15,
                                                dcol: 1,
                                                w: 1,
                                                h: 1,
                                                group: colors)
end

def light_blue
  { r: 128, g: 255, b: 255 }
end

def yellow
  { r: 255, g: 255, b: 128 }
end

def green
  { r: 0, g: 128, b: 80 }
end

def white
  { r: 255, g: 255, b: 255 }
end

def label_color
  { r: 0, g: 0, b: 0 }
end

$gtk.reset

19 Layouts Extended Parameters - main.rb link

# ./samples/07_advanced_rendering/19_layouts_extended_parameters/app/main.rb
def tick args
  args.state.origin ||= :top_left
  args.state.safe_area ||= :yes

  args.outputs.watch "Instructions:"
  args.outputs.watch "Use tab to change origin, use space to toggle safe area."
  args.outputs.watch "origin: #{args.state.origin}"
  args.outputs.watch "safe_area: #{args.state.safe_area}"

  if args.inputs.keyboard.key_down.tab
    if args.state.origin == :top_left
      args.state.origin = :top_right
    elsif args.state.origin == :top_right
      args.state.origin = :bottom_right
    elsif args.state.origin == :bottom_right
      args.state.origin = :bottom_left
    elsif args.state.origin == :bottom_left
      args.state.origin = :top_left
    end
  end

  if args.inputs.keyboard.key_down.space
    if args.state.safe_area == :yes
      args.state.safe_area = :no
    elsif args.state.safe_area == :no
      args.state.safe_area = :yes
    end
  end

  origin = args.state.origin
  safe_area = args.state.safe_area == :yes

  sub_grid = Layout.rect(row: 0,
                         col: 0,
                         w: 4,
                         h: 5,
                         include_row_gutter: true,
                         include_col_gutter: true,
                         origin: origin,
                         safe_area: safe_area)

  slots ||= {}
  20.times do |i|
    row = i.idiv(4)
    col = i % 4
    slots[i] = Layout.rect(row: i.idiv(4),
                           col: i % 4,
                           w: 1,
                           h: 1,
                           safe_area: safe_area,
                           origin: origin)
                     .merge(row: row, col: col)
  end

  args.outputs.primitives << Layout.debug_primitives
  args.outputs.primitives << sub_grid.merge(path: :solid, r: 255, g: 0, b: 0, a: 255)
  args.outputs.primitives << slots.values.map { |r| r.merge(path: :solid, r: 0, g: 0, b: 0, a: 255) }
  args.outputs.primitives << slots.values.map { |r| r.center.merge(text: "#{r.row},#{r.col}", r: 255, g: 255, b: 255, anchor_x: 0.5, anchor_y: 0.5) }
end

Advanced Rendering Hd link

Hd Labels - main.rb link

# ./samples/07_advanced_rendering_hd/01_hd_labels/app/main.rb
def tick args
  args.state.output_cycle ||= :top_level

  args.outputs.background_color = [0, 0, 0]
  args.outputs.solids << [0, 0, 1280, 720, 255, 255, 255]
  if args.state.output_cycle == :top_level
    render_main args
  else
    render_scene args
  end

  # cycle between labels in top level args.outputs
  # and labels inside of render target
  if Kernel.tick_count.zmod? 300
    if args.state.output_cycle == :top_level
      args.state.output_cycle = :render_target
    else
      args.state.output_cycle = :top_level
    end
  end
end

def render_main args
  # center line
  args.outputs.lines   << { x:   0, y: 360, x2: 1280, y2: 360 }
  args.outputs.lines   << { x: 640, y:   0, x2:  640, y2: 720 }

  # horizontal ruler
  args.outputs.lines   << { x:   0, y: 370, x2: 1280, y2: 370 }
  args.outputs.lines   << { x:   0, y: 351, x2: 1280, y2: 351 }

  # vertical ruler
  args.outputs.lines   << { x:  575, y: 0, x2: 575, y2: 720 }
  args.outputs.lines   << { x:  701, y: 0, x2: 701, y2: 720 }

  args.outputs.sprites << { x: 640 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square/blue.png", a: 128 }
  args.outputs.labels  << { x:  640, y:   0, text: "(bottom)",  alignment_enum: 1, vertical_alignment_enum: 0 }
  args.outputs.labels  << { x:  640, y: 425, text: "top_level", alignment_enum: 1, vertical_alignment_enum: 1 }
  args.outputs.labels  << { x:  640, y: 720, text: "(top)",     alignment_enum: 1, vertical_alignment_enum: 2 }
  args.outputs.labels  << { x:    0, y: 360, text: "(left)",    alignment_enum: 0, vertical_alignment_enum: 1 }
  args.outputs.labels  << { x: 1280, y: 360, text: "(right)",   alignment_enum: 2, vertical_alignment_enum: 1 }
end

def render_scene args
  args.outputs[:scene].background_color = [255, 255, 255, 0]

  # center line
  args.outputs[:scene].lines   << { x:   0, y: 360, x2: 1280, y2: 360 }
  args.outputs[:scene].lines   << { x: 640, y:   0, x2:  640, y2: 720 }

  # horizontal ruler
  args.outputs[:scene].lines   << { x:   0, y: 370, x2: 1280, y2: 370 }
  args.outputs[:scene].lines   << { x:   0, y: 351, x2: 1280, y2: 351 }

  # vertical ruler
  args.outputs[:scene].lines   << { x:  575, y: 0, x2: 575, y2: 720 }
  args.outputs[:scene].lines   << { x:  701, y: 0, x2: 701, y2: 720 }

  args.outputs[:scene].sprites << { x: 640 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square/blue.png", a: 128, blendmode_enum: 0 }
  args.outputs[:scene].labels  << { x:  640, y:   0, text: "(bottom)",      alignment_enum: 1, vertical_alignment_enum: 0, blendmode_enum: 0 }
  args.outputs[:scene].labels  << { x:  640, y: 425, text: "render target", alignment_enum: 1, vertical_alignment_enum: 1, blendmode_enum: 0 }
  args.outputs[:scene].labels  << { x:  640, y: 720, text: "(top)",         alignment_enum: 1, vertical_alignment_enum: 2, blendmode_enum: 0 }
  args.outputs[:scene].labels  << { x:    0, y: 360, text: "(left)",        alignment_enum: 0, vertical_alignment_enum: 1, blendmode_enum: 0 }
  args.outputs[:scene].labels  << { x: 1280, y: 360, text: "(right)",       alignment_enum: 2, vertical_alignment_enum: 1, blendmode_enum: 0 }

  args.outputs.sprites << { x: 0, y: 0, w: 1280, h: 720, path: :scene }
end

Texture Atlases - main.rb link

# ./samples/07_advanced_rendering_hd/02_texture_atlases/app/main.rb
# With HD mode enabled. DragonRuby will automatically use HD sprites given the following
# naming convention (assume we are using a sprite called =player.png=):
#
# | Name  | Resolution | File Naming Convention        |
# |-------+------------+-------------------------------|
# | 720p  |   1280x720 | =player.png=                  |
# | HD+   |   1600x900 | [email protected]=              |
# | 1080p |  1920x1080 | [email protected]=              |
# | 1440p |  2560x1440 | [email protected]=              |
# | 1800p |  3200x1800 | [email protected]=              |
# | 4k    |  3200x2160 | [email protected]=              |
# | 5k    |  6400x2880 | [email protected]=              |

# Note: Review the sample app's game_metadata.txt file for what configurations are enabled.

def tick args
  args.outputs.background_color = [0, 0, 0]
  args.outputs.borders << { x: 0, y: 0, w: 1280, h: 720, r: 255, g: 255, b: 255 }

  args.outputs.labels << { x: 30, y: 30.from_top, text: "render scale: #{args.grid.native_scale}", r: 255, g: 255, b: 255 }
  args.outputs.labels << { x: 30, y: 60.from_top, text: "render scale: #{args.grid.native_scale_enum}", r: 255, g: 255, b: 255 }

  args.outputs.sprites << { x: -640 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x: -320 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square.png" }

  args.outputs.sprites << { x:    0 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x:  320 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x:  640 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x:  960 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x: 1280 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square.png" }

  args.outputs.sprites << { x: 1600 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x: 1920 - 50, y: 360 - 50, w: 100, h: 100, path: "sprites/square.png" }

  args.outputs.sprites << { x:  640 - 50, y:          720, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x:  640 - 50, y: 100.from_top, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x:  640 - 50, y:     360 - 50, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x:  640 - 50, y:            0, w: 100, h: 100, path: "sprites/square.png" }
  args.outputs.sprites << { x:  640 - 50, y:         -100, w: 100, h: 100, path: "sprites/square.png" }
end

Allscreen Properties - main.rb link

# ./samples/07_advanced_rendering_hd/03_allscreen_properties/app/main.rb
def tick args
  label_style = { r: 255, g: 255, b: 255, size_enum: 4 }
  args.outputs.background_color = [0, 0, 0]
  args.outputs.borders << { x: 0, y: 0, w: 1280, h: 720, r: 255, g: 255, b: 255 }

  args.outputs.labels << { x: 10, y:  10.from_top, text: "texture_scale:       #{args.grid.texture_scale}", **label_style }
  args.outputs.labels << { x: 10, y:  40.from_top, text: "texture_scale_enum:  #{args.grid.texture_scale_enum}",  **label_style }
  args.outputs.labels << { x: 10, y:  70.from_top, text: "allscreen_offset_x:  #{args.grid.allscreen_offset_x}", **label_style }
  args.outputs.labels << { x: 10, y: 100.from_top, text: "allscreen_offset_y:  #{args.grid.allscreen_offset_y}", **label_style }

  if (Kernel.tick_count % 500) < 250
    args.outputs.labels << { x: 10, y: 130.from_top, text: "cropped to:          grid", **label_style }

    args.outputs.sprites << { x:        args.grid.left,
                              y:        args.grid.bottom,
                              w:        args.grid.w,
                              h:        args.grid.h,
                              # world.png has a 720p baseline size of 2000x2000 pixels
                              # we want to crop the center of the sprite
                              # wrt the bounds of the safe area.
                              source_x: 2000 - args.grid.w / 2,
                              source_y: 2000 - args.grid.h / 2,
                              source_w: 1280,
                              source_h: 720,
                              path: "sprites/world.png" } # world.png has a 720p baseline size of 2000x2000 pixels
  else
    args.outputs.labels << { x: 10, y: 130.from_top, text: "cropped to:          allscreen", **label_style }

    args.outputs.sprites << { x:        args.grid.allscreen_left,
                              y:        args.grid.allscreen_bottom,
                              w:        args.grid.allscreen_w,
                              h:        args.grid.allscreen_h,
                              # world.png has a 720p baseline size of 2000x2000 pixels
                              # we want to crop the center of the sprite to the bounds
                              # wrt to the bounds of the entire renderable area.
                              source_x: 2000 - args.grid.allscreen_w / 2,
                              source_y: 2000 - args.grid.allscreen_h / 2,
                              source_w: args.grid.allscreen_w,
                              source_h: args.grid.allscreen_h,
                              path:     "sprites/world.png" }
  end

  args.outputs.sprites << { x: 0, y: 0.from_top - 165, w: 410, h: 165, r: 0, g: 0, b: 0, a: 200, path: :pixel }
end

Layouts And Portrait Mode - main.rb link

# ./samples/07_advanced_rendering_hd/04_layouts_and_portrait_mode/app/main.rb
def tick args
  args.outputs.solids << args.layout.rect(row: 0, col: 0, w: 12, h: 24, include_row_gutter: true, include_col_gutter: true).merge(b: 255, a: 80)

  # rows (light blue)
  light_blue = { r: 128, g: 255, b: 255 }
  args.outputs.labels << args.layout.rect(row: 1, col: 3).merge(text: "row examples", vertical_alignment_enum: 1, alignment_enum: 1)
  4.map_with_index do |row|
    args.outputs.solids << args.layout.rect(row: row, col: 0, w: 1, h: 1).merge(**light_blue)
  end

  2.map_with_index do |row|
    args.outputs.solids << args.layout.rect(row: row * 2, col: 1, w: 1, h: 2).merge(**light_blue)
  end

  4.map_with_index do |row|
    args.outputs.solids << args.layout.rect(row: row, col: 2, w: 2, h: 1).merge(**light_blue)
  end

  2.map_with_index do |row|
    args.outputs.solids << args.layout.rect(row: row * 2, col: 4, w: 2, h: 2).merge(**light_blue)
  end

  # columns (yellow)
  yellow = { r: 255, g: 255, b: 128 }
  args.outputs.labels << args.layout.rect(row: 1, col: 9).merge(text: "column examples", vertical_alignment_enum: 1, alignment_enum: 1)
  6.times do |col|
    args.outputs.solids << args.layout.rect(row: 0, col: 6 + col, w: 1, h: 1).merge(**yellow)
  end

  3.times do |col|
    args.outputs.solids << args.layout.rect(row: 1, col: 6 + col * 2, w: 2, h: 1).merge(**yellow)
  end

  6.times do |col|
    args.outputs.solids << args.layout.rect(row: 2, col: 6 + col, w: 1, h: 2).merge(**yellow)
  end

  # max width/height baseline (transparent green)
  green = { r: 0, g: 128, b: 80 }
  args.outputs.labels << args.layout.rect(row: 4, col: 6).merge(text: "max width/height examples", vertical_alignment_enum: 1, alignment_enum: 1)
  args.outputs.solids << args.layout.rect(row: 4, col: 0, w: 12, h: 2).merge(a: 64, **green)

  # max height
  args.outputs.solids << args.layout.rect(row: 4, col: 0, w: 12, h: 2, max_height: 1).merge(a: 64, **green)

  # max width
  args.outputs.solids << args.layout.rect(row: 4, col: 0, w: 12, h: 2, max_width: 6).merge(a: 64, **green)

  # labels relative to rects
  label_color = { r: 0, g: 0, b: 0 }
  white = { r: 232, g: 232, b: 232 }

  # labels realtive to point, achored at 0.0, 0.0
  args.outputs.labels << args.layout.rect(row: 5.5, col: 6).merge(text: "labels using args.layout.point anchored to 0.0, 0.0", vertical_alignment_enum: 1, alignment_enum: 1)
  grey = { r: 128, g: 128, b: 128 }
  args.outputs.solids << args.layout.rect(row: 7, col: 4).merge(**grey)
  args.outputs.labels << args.layout.point(row: 7, col: 4, row_anchor: 1.0, col_anchor: 0.0).merge(text: "[x]", alignment_enum: 1, vertical_alignment_enum: 1, **label_color)

  args.outputs.solids << args.layout.rect(row: 7, col: 5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 7, col: 5, row_anchor: 1.0, col_anchor: 0.5).merge(text: "[x]", alignment_enum: 1, vertical_alignment_enum: 1, **label_color)

  args.outputs.solids << args.layout.rect(row: 7, col: 6).merge(**grey)
  args.outputs.labels << args.layout.point(row: 7, col: 6, row_anchor: 1.0, col_anchor: 1.0).merge(text: "[x]", alignment_enum: 1, vertical_alignment_enum: 1, **label_color)

  args.outputs.solids << args.layout.rect(row: 8, col: 4).merge(**grey)
  args.outputs.labels << args.layout.point(row: 8, col: 4, row_anchor: 0.5, col_anchor: 0.0).merge(text: "[x]", alignment_enum: 1, vertical_alignment_enum: 1, **label_color)

  args.outputs.solids << args.layout.rect(row: 8, col: 5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 8, col: 5, row_anchor: 0.5, col_anchor: 0.5).merge(text: "[x]", alignment_enum: 1, vertical_alignment_enum: 1, **label_color)

  args.outputs.solids << args.layout.rect(row: 8, col: 6).merge(**grey)
  args.outputs.labels << args.layout.point(row: 8, col: 6, row_anchor: 0.5, col_anchor: 1.0).merge(text: "[x]", alignment_enum: 1, vertical_alignment_enum: 1, **label_color)

  args.outputs.solids << args.layout.rect(row: 9, col: 4).merge(**grey)
  args.outputs.labels << args.layout.point(row: 9, col: 4, row_anchor: 0.0, col_anchor: 0.0).merge(text: "[x]", alignment_enum: 1, vertical_alignment_enum: 1, **label_color)

  args.outputs.solids << args.layout.rect(row: 9, col: 5).merge(**grey)
  args.outputs.labels << args.layout.point(row: 9, col: 5, row_anchor: 0.0, col_anchor: 0.5).merge(text: "[x]", alignment_enum: 1, vertical_alignment_enum: 1, **label_color)

  args.outputs.solids << args.layout.rect(row: 9, col: 6).merge(**grey)
  args.outputs.labels << args.layout.point(row: 9, col: 6, row_anchor: 0.0, col_anchor: 1.0).merge(text: "[x]", alignment_enum: 1, vertical_alignment_enum: 1, **label_color)

  # centering rects
  args.outputs.labels << args.layout.rect(row: 10.5, col: 6).merge(text: "layout.rect centered inside another layout.rect", vertical_alignment_enum: 1, alignment_enum: 1)
  outer_rect = args.layout.rect(row: 12, col: 4, w: 3, h: 3)

  # render outer rect
  args.outputs.solids << outer_rect.merge(**light_blue)

  # center a yellow rect with w and h of two
  args.outputs.solids << args.layout.rect_center(
    args.layout.rect(w: 1, h: 5), # inner rect
    outer_rect, # outer rect
  ).merge(**yellow)

  # center a black rect with w three h of one
  args.outputs.solids << args.layout.rect_center(
    args.layout.rect(w: 5, h: 1), # inner rect
    outer_rect, # outer rect
  )

  args.outputs.labels << args.layout.rect(row: 16.5, col: 6).merge(text: "layout.rect_group usage", vertical_alignment_enum: 1, alignment_enum: 1)

  horizontal_markers = [
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 }
  ]

  args.outputs.solids << args.layout.rect_group(row: 18,
                                                dcol: 1,
                                                w: 1,
                                                h: 1,
                                                group: horizontal_markers)

  vertical_markers = [
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 },
    { r: 0, g: 0, b: 0 }
  ]

  args.outputs.solids << args.layout.rect_group(row: 18,
                                                drow: 1,
                                                w: 1,
                                                h: 1,
                                                group: vertical_markers)

  colors = [
    { r:   0, g:   0, b:   0 },
    { r:  50, g:  50, b:  50 },
    { r: 100, g: 100, b: 100 },
    { r: 150, g: 150, b: 150 },
    { r: 200, g: 200, b: 200 },
  ]

  args.outputs.solids << args.layout.rect_group(row: 19,
                                                col: 1,
                                                dcol: 2,
                                                w: 2,
                                                h: 1,
                                                group: colors)

  args.outputs.solids << args.layout.rect_group(row: 19,
                                                col: 1,
                                                drow: 1,
                                                w: 2,
                                                h: 1,
                                                group: colors)
end

$gtk.reset

Tweening Lerping Easing Functions link

Easing Functions - main.rb link

# ./samples/08_tweening_lerping_easing_functions/01_easing_functions/app/main.rb
def tick args
  # STOP! Watch the following presentation first!!!!
  # Math for Game Programmers: Fast and Funky 1D Nonlinear Transformations
  # https://www.youtube.com/watch?v=mr5xkf6zSzk

  # You've watched the talk, yes? YES???

  # define starting and ending points of properties to animate
  args.state.target_x = 1180
  args.state.target_y = 620
  args.state.target_w = 100
  args.state.target_h = 100
  args.state.starting_x = 0
  args.state.starting_y = 0
  args.state.starting_w = 300
  args.state.starting_h = 300

  # define start time and duration of animation
  args.state.start_animate_at = 3.seconds # this is the same as writing 60 * 5 (or 300)
  args.state.duration = 2.seconds # this is the same as writing 60 * 2 (or 120)

  # define type of animations
  # Here are all the options you have for values you can put in the array:
  # :identity, :quad, :cube, :quart, :quint, :flip

  # Linear is defined as:
  # [:identity]
  #
  # Smooth start variations are:
  # [:quad]
  # [:cube]
  # [:quart]
  # [:quint]

  # Linear reversed, and smooth stop are the same as the animations defined above, but reversed:
  # [:flip, :identity, :flip]
  # [:flip, :quad, :flip]
  # [:flip, :cube, :flip]
  # [:flip, :quart, :flip]
  # [:flip, :quint, :flip]

  # You can also do custom definitions. See the bottom of the file details
  # on how to do that. I've defined a couple for you:
  # [:smoothest_start]
  # [:smoothest_stop]

  # CHANGE THIS LINE TO ONE OF THE LINES ABOVE TO SEE VARIATIONS
  args.state.animation_type = [:identity]
  # args.state.animation_type = [:quad]
  # args.state.animation_type = [:cube]
  # args.state.animation_type = [:quart]
  # args.state.animation_type = [:quint]
  # args.state.animation_type = [:flip, :identity, :flip]
  # args.state.animation_type = [:flip, :quad, :flip]
  # args.state.animation_type = [:flip, :cube, :flip]
  # args.state.animation_type = [:flip, :quart, :flip]
  # args.state.animation_type = [:flip, :quint, :flip]
  # args.state.animation_type = [:smoothest_start]
  # args.state.animation_type = [:smoothest_stop]

  # THIS IS WHERE THE MAGIC HAPPENS!
  # Numeric#ease
  progress = args.state.start_animate_at.ease(args.state.duration, args.state.animation_type)

  # Numeric#ease needs to called:
  # 1. On the number that represents the point in time you want to start, and takes two parameters:
  #   a. The first parameter is how long the animation should take.
  #   b. The second parameter represents the functions that need to be called.
  #
  # For example, if I wanted an animate to start 3 seconds in, and last for 10 seconds,
  # and I want to animation to start fast and end slow, I would do:
  # (60 * 3).ease(60 * 10, :flip, :quint, :flip)

  #        initial value           delta to the final value
  calc_x = args.state.starting_x + (args.state.target_x - args.state.starting_x) * progress
  calc_y = args.state.starting_y + (args.state.target_y - args.state.starting_y) * progress
  calc_w = args.state.starting_w + (args.state.target_w - args.state.starting_w) * progress
  calc_h = args.state.starting_h + (args.state.target_h - args.state.starting_h) * progress

  args.outputs.solids << [calc_x, calc_y, calc_w, calc_h, 0, 0, 0]

  # count down
  count_down = args.state.start_animate_at - Kernel.tick_count
  if count_down > 0
    args.outputs.labels << [640, 375, "Running: #{args.state.animation_type} in...", 3, 1]
    args.outputs.labels << [640, 345, "%.2f" % count_down.fdiv(60), 3, 1]
  elsif progress >= 1
    args.outputs.labels << [640, 360, "Click screen to reset.", 3, 1]
    if args.inputs.click
      $gtk.reset
    end
  end
end

# $gtk.reset

# you can make own variations of animations using this
module Easing
  # you have access to all the built in functions: identity, flip, quad, cube, quart, quint
  def self.smoothest_start x
    quad(quint(x))
  end

  def self.smoothest_stop x
    flip(quad(quint(flip(x))))
  end

  # this is the source for the existing easing functions
  def self.identity x
    x
  end

  def self.flip x
    1 - x
  end

  def self.quad x
    x * x
  end

  def self.cube x
    x * x * x
  end

  def self.quart x
    x * x * x * x * x
  end

  def self.quint x
    x * x * x * x * x * x
  end
end

Cubic Bezier - main.rb link

# ./samples/08_tweening_lerping_easing_functions/02_cubic_bezier/app/main.rb
def tick args
  args.outputs.background_color = [33, 33, 33]
  args.outputs.lines << bezier(100, 100,
                               100, 620,
                               1180, 620,
                               1180, 100,
                               0)

  args.outputs.lines << bezier(100, 100,
                               100, 620,
                               1180, 620,
                               1180, 100,
                               20)
end


def bezier x, y, x2, y2, x3, y3, x4, y4, step
  step ||= 0
  color = [200, 200, 200]
  points = points_for_bezier [x, y], [x2, y2], [x3, y3], [x4, y4], step

  points.each_cons(2).map do |p1, p2|
    [p1, p2, color]
  end
end

def points_for_bezier p1, p2, p3, p4, step
  points = []
  if step == 0
    [p1, p2, p3, p4]
  else
    t_step = 1.fdiv(step + 1)
    t = 0
    t += t_step
    points = []
    while t < 1
      points << [
        b_for_t(p1.x, p2.x, p3.x, p4.x, t),
        b_for_t(p1.y, p2.y, p3.y, p4.y, t),
      ]
      t += t_step
    end

    [
      p1,
      *points,
      p4
    ]
  end
end

def b_for_t v0, v1, v2, v3, t
  pow(1 - t, 3) * v0 +
  3 * pow(1 - t, 2) * t * v1 +
  3 * (1 - t) * pow(t, 2) * v2 +
  pow(t, 3) * v3
end

def pow n, to
  n ** to
end

Easing Using Spline - main.rb link

# ./samples/08_tweening_lerping_easing_functions/03_easing_using_spline/app/main.rb
def tick args
  args.state.duration = 10.seconds
  args.state.spline = [
    [0.0, 0.33, 0.66, 1.0],
    [1.0, 1.0,  1.0,  1.0],
    [1.0, 0.66, 0.33, 0.0],
  ]

  args.state.simulation_tick = Kernel.tick_count % args.state.duration
  progress = 0.ease_spline_extended args.state.simulation_tick, args.state.duration, args.state.spline
  args.outputs.borders << args.grid.rect
  args.outputs.solids << [20 + 1240 * progress,
                          20 +  680 * progress,
                          20, 20].anchor_rect(0.5, 0.5)
  args.outputs.labels << [10,
                          710,
                          "perc: #{"%.2f" % (args.state.simulation_tick / args.state.duration)} t: #{args.state.simulation_tick}"]
end

Pulsing Button - main.rb link

# ./samples/08_tweening_lerping_easing_functions/04_pulsing_button/app/main.rb
# game concept from: https://youtu.be/Tz-AinJGDIM

# This class encapsulates the logic of a button that pulses when clicked.
# It is used in the StartScene and GameOverScene classes.
class PulseButton
  # a block is passed into the constructor and is called when the button is clicked,
  # and after the pulse animation is complete
  def initialize rect, text, &on_click
    @rect = rect
    @text = text
    @on_click = on_click
    @pulse_animation_spline = [[0.0, 0.90, 1.0, 1.0], [1.0, 0.10, 0.0, 0.0]]
    @duration = 10
  end

  # the button is ticked every frame and check to see if the mouse
  # intersects the button's bounding box.
  # if it does, then pertinent information is stored in the @clicked_at variable
  # which is used to calculate the pulse animation
  def tick tick_count, mouse
    @tick_count = tick_count

    if @clicked_at && @clicked_at.elapsed_time > @duration
      @clicked_at = nil
      @on_click.call
    end

    return if !mouse.click
    return if !mouse.inside_rect? @rect
    @clicked_at = tick_count
  end

  # this function returns an array of primitives that can be rendered
  def prefab easing
    # calculate the percentage of the pulse animation that has completed
    # and use the percentage to compute the size and position of the button
    perc = if @clicked_at
             easing.ease_spline @clicked_at, @tick_count, @duration, @pulse_animation_spline
           else
             0
           end

    rect = { x: @rect.x - 50 * perc / 2,
             y: @rect.y - 50 * perc / 2,
             w: @rect.w + 50 * perc,
             h: @rect.h + 50 * perc }

    point = { x: @rect.x + @rect.w / 2, y: @rect.y + @rect.h / 2 }
    [
      { **rect, path: :pixel },
      { **point, text: @text, size_px: 32, anchor_x: 0.5, anchor_y: 0.5 }
    ]
  end
end

class Game
  attr_gtk

  def initialize args
    self.args = args
    @pulse_button ||= PulseButton.new({ x: 640 - 100, y: 360 - 50, w: 200, h: 100 }, 'Click Me!') do
      $gtk.notify! "Animation complete and block invoked!"
    end
  end

  def tick
    @pulse_button.tick Kernel.tick_count, inputs.mouse
    outputs.primitives << @pulse_button.prefab(easing)
  end
end

def tick args
  $game ||= Game.new args
  $game.args = args
  $game.tick
end

Scene Transitions - main.rb link

# ./samples/08_tweening_lerping_easing_functions/05_scene_transitions/app/main.rb
# This sample app shows a more advanced implementation of scenes:
# 1. "Scene 1" has a label on it that says "I am scene ONE. Press enter to go to scene TWO."
# 2. "Scene 2" has a label on it that says "I am scene TWO. Press enter to go to scene ONE."
# 3. When the game starts, Scene 1 is presented.
# 4. When the player presses enter, the scene transitions to Scene 2 (fades out Scene 1 over half a second, then fades in Scene 2 over half a second).
# 5. When the player presses enter again, the scene transitions to Scene 1 (fades out Scene 2 over half a second, then fades in Scene 1 over half a second).
# 6. During the fade transitions, spamming the enter key is ignored (scenes don't accept a transition/respond to the enter key until the current transition is completed).
class SceneOne
  attr_gtk

  def tick
    outputs[:scene].labels << { x: 640,
                                y: 360,
                                text: "I am scene ONE. Press enter to go to scene TWO.",
                                alignment_enum: 1,
                                vertical_alignment_enum: 1 }

    state.next_scene = :scene_two if inputs.keyboard.key_down.enter
  end
end

class SceneTwo
  attr_gtk

  def tick
    outputs[:scene].labels << { x: 640,
                                y: 360,
                                text: "I am scene TWO. Press enter to go to scene ONE.",
                                alignment_enum: 1,
                                vertical_alignment_enum: 1 }

    state.next_scene = :scene_one if inputs.keyboard.key_down.enter
  end
end

class RootScene
  attr_gtk

  def initialize
    @scene_one = SceneOne.new
    @scene_two = SceneTwo.new
  end

  def tick
    defaults
    render
    tick_scene
  end

  def defaults
    set_current_scene! :scene_one if Kernel.tick_count == 0
    state.scene_transition_duration ||= 30
  end

  def render
    a = if state.transition_scene_at
          255 * state.transition_scene_at.ease(state.scene_transition_duration, :flip)
        elsif state.current_scene_at
          255 * state.current_scene_at.ease(state.scene_transition_duration)
        else
          255
        end

    outputs.sprites << { x: 0, y: 0, w: 1280, h: 720, path: :scene, a: a }
  end

  def tick_scene
    current_scene = state.current_scene

    @current_scene.args = args
    @current_scene.tick

    if current_scene != state.current_scene
      raise "state.current_scene changed mid tick from #{current_scene} to #{state.current_scene}. To change scenes, set state.next_scene."
    end

    if state.next_scene && state.next_scene != state.transition_scene && state.next_scene != state.current_scene
      state.transition_scene_at = Kernel.tick_count
      state.transition_scene = state.next_scene
    end

    if state.transition_scene_at && state.transition_scene_at.elapsed_time >= state.scene_transition_duration
      set_current_scene! state.transition_scene
    end

    state.next_scene = nil
  end

  def set_current_scene! id
    return if state.current_scene == id
    state.current_scene = id
    state.current_scene_at = Kernel.tick_count
    state.transition_scene = nil
    state.transition_scene_at = nil

    if state.current_scene == :scene_one
      @current_scene = @scene_one
    elsif state.current_scene == :scene_two
      @current_scene = @scene_two
    end
  end
end

def tick args
  $game ||= RootScene.new
  $game.args = args
  $game.tick
end

Animation Queues - main.rb link

# ./samples/08_tweening_lerping_easing_functions/06_animation_queues/app/main.rb
# here's how to create a "fire and forget" sprite animation queue
def tick args
  args.outputs.labels << { x: 640,
                           y: 360,
                           text: "Click anywhere on the screen.",
                           alignment_enum: 1,
                           vertical_alignment_enum: 1 }

  # initialize the queue to an empty array
  args.state.fade_out_queue ||=[]

  # if the mouse is click, add a sprite to the fire and forget
  # queue to be processed
  if args.inputs.mouse.click
    args.state.fade_out_queue << {
      x: args.inputs.mouse.x - 20,
      y: args.inputs.mouse.y - 20,
      w: 40,
      h: 40,
      path: "sprites/square/blue.png"
    }
  end

  # process the queue
  args.state.fade_out_queue.each do |item|
    # default the alpha value if it isn't specified
    item.a ||= 255

    # decrement the alpha by 5 each frame
    item.a -= 5
  end

  # remove the item if it's completely faded out
  args.state.fade_out_queue.reject! { |item| item.a <= 0 }

  # render the sprites in the queue
  args.outputs.sprites << args.state.fade_out_queue
end

Animation Queues Advanced - main.rb link

# ./samples/08_tweening_lerping_easing_functions/07_animation_queues_advanced/app/main.rb
# sample app shows how to perform a fire and forget animation when a collision occurs
def tick args
  defaults args
  spawn_bullets args
  calc_bullets args
  render args
end

def defaults args
  # place a player on the far left with sprite and hp information
  args.state.player ||= { x: 100, y: 360 - 50, w: 100, h: 100, path: "sprites/square/blue.png", hp: 30 }
  # create an array of bullets
  args.state.bullets ||= []
  # create a queue for handling bullet explosions
  args.state.explosion_queue ||= []
end

def spawn_bullets args
  # span a bullet in a random location on the far right every half second
  return if !Kernel.tick_count.zmod? 30
  args.state.bullets << {
    x: 1280 - 100,
    y: rand(720 - 100),
    w: 100,
    h: 100,
    path: "sprites/square/red.png"
  }
end

def calc_bullets args
  # for each bullet
  args.state.bullets.each do |b|
    # move it to the left by 20 pixels
    b.x -= 20

    # determine if the bullet collides with the player
    if b.intersect_rect? args.state.player
      # decrement the player's health if it does
      args.state.player.hp -= 1
      # mark the bullet as exploded
      b.exploded = true

      # queue the explosion by adding it to the explosion queue
      args.state.explosion_queue << b.merge(exploded_at: Kernel.tick_count)
    end
  end

  # remove bullets that have exploded so they wont be rendered
  args.state.bullets.reject! { |b| b.exploded }

  # remove animations from the animation queue that have completed
  # frame index will return nil once the animation has completed
  args.state.explosion_queue.reject! { |e| !e.exploded_at.frame_index(7, 4, false) }
end

def render args
  # render the player's hp above the sprite
  args.outputs.labels << {
    x: args.state.player.x + 50,
    y: args.state.player.y + 110,
    text: "#{args.state.player.hp}",
    alignment_enum: 1,
    vertical_alignment_enum: 0
  }

  # render the player
  args.outputs.sprites << args.state.player

  # render the bullets
  args.outputs.sprites << args.state.bullets

  # process the animation queue
  args.outputs.sprites << args.state.explosion_queue.map do |e|
    number_of_frames = 7
    hold_each_frame_for = 4
    repeat_animation = false
    # use the exploded_at property and the frame_index function to determine when the animation should start
    frame_index = e.exploded_at.frame_index(number_of_frames, hold_each_frame_for, repeat_animation)
    # take the explosion primitive and set the path variariable
    e.merge path: "sprites/misc/explosion-#{frame_index}.png"
  end
end

Cutscenes - main.rb link

# ./samples/08_tweening_lerping_easing_functions/08_cutscenes/app/main.rb
# sample app shows how you can user a queue/callback mechanism to create cutscenes
class Game
  attr_gtk

  def initialize
    # this class controls the cutscene orchestration
    @tick_queue = TickQueue.new
  end

  def tick
    @tick_queue.args = args
    state.player ||= { x: 0, y: 0, w: 100, h: 100, path: :pixel, r: 0, g: 255, b: 0 }
    state.fade_to_black ||= 0
    state.back_and_forth_count ||= 0

    # if the mouse is clicked, start the cutscene
    if inputs.mouse.click && !state.cutscene_started
      start_cutscene
    end

    outputs.primitives << state.player
    outputs.primitives << { x: 0, y: 0, w: 1280, h: 720, path: :pixel, r: 0, g: 0, b: 0, a: state.fade_to_black }
    @tick_queue.tick
  end

  def start_cutscene
    # don't start the cutscene if it's already started
    return if state.cutscene_started
    state.cutscene_started = true

    # start the cutscene by moving right
    queue_move_to_right_side
  end

  def queue_move_to_right_side
    # use the tick queue mechanism to kick off the player moving right
    @tick_queue.queue_tick Kernel.tick_count do |args, entry|
      state.player.x += 30
      # once the player is done moving right, stage the next step of the cutscene (moving left)
      if state.player.x + state.player.w > 1280
        state.player.x = 1280 - state.player.w
        queue_move_to_left_side

        # marke the queued tick entry as complete so it doesn't get run again
        entry.complete!
      end
    end
  end

  def queue_move_to_left_side
    # use the tick queue mechanism to kick off the player moving right
    @tick_queue.queue_tick Kernel.tick_count do |args, entry|
      args.state.player.x -= 30
      # once the player id done moving left, decide on whether they should move right again or fade to black
      # the decision point is based on the number of times the player has moved left and right
      if args.state.player.x < 0
        state.player.x = 0
        args.state.back_and_forth_count += 1
        if args.state.back_and_forth_count < 3
          # if they haven't moved left and right 3 times, move them right again
          queue_move_to_right_side
        else
          # if they have moved left and right 3 times, fade to black
          queue_fade_to_black
        end

        # marke the queued tick entry as complete so it doesn't get run again
        entry.complete!
      end
    end
  end

  def queue_fade_to_black
    # we know the cutscene will end in 255 tickes, so we can queue a notification that will kick off in the future notifying that the cutscene is done
    @tick_queue.queue_one_time_tick Kernel.tick_count + 255 do |args, entry|
      $gtk.notify "Cutscene complete!"
    end

    # start the fade to black
    @tick_queue.queue_tick Kernel.tick_count do |args, entry|
      args.state.fade_to_black += 1
      entry.complete! if state.fade_to_black > 255
    end
  end
end

# this construct handles the execution of animations/cutscenes
# the key methods that are used are queue_tick and queue_one_time_tick
class TickQueue
  attr_gtk

  attr :queued_ticks
  attr :queued_ticks_currently_running

  def initialize
    @queued_ticks ||= {}
    @queued_ticks_currently_running ||= []
  end

  # adds a callback that will be processed
  def queue_tick at, &block
    @queued_ticks[at] ||= []
    @queued_ticks[at] << QueuedTick.new(at, &block)
  end

  # adds a callback that will be processed and immediately marked as complete
  def queue_one_time_tick at, **metadata, &block
    @queued_ticks ||= {}
    @queued_ticks[at] ||= []
    @queued_ticks[at] << QueuedOneTimeTick.new(at, &block)
  end

  def tick
    # get all queued callbacs that need to start running on the current frame
    entries_this_tick = @queued_ticks.delete Kernel.tick_count

    # if there are values, then add them to the list of currently running callbacks
    if entries_this_tick
      @queued_ticks_currently_running.concat entries_this_tick
    end

    # run tick on each entry
    @queued_ticks_currently_running.each do |queued_tick|
      queued_tick.tick args
    end

    # remove all entries that are complete
    @queued_ticks_currently_running.reject!(&:complete?)

    # there is a chance that a queued tick will queue another tick, so we need to check
    # if there are any queued ticks for the current frame. if so, then recursively call tick again
    if @queued_ticks[Kernel.tick_count] && @queued_ticks[Kernel.tick_count].length > 0
      tick
    end
  end
end

# small data structure that holds the callback and status
# queue_tick constructs an instance of this class to faciltate
# the execution of the block and it's completion
class QueuedTick
  attr :queued_at, :block

  def initialize queued_at, &block
    @queued_at = queued_at
    @is_complete = false
    @block = block
  end

  def complete!
    @is_complete = true
  end

  def complete?
    @is_complete
  end

  def tick args
    @block.call args, self
  end
end

# small data structure that holds the callback and status
# queue_one_time_tick constructs an instance of this class to faciltate
# the execution of the block and it's completion
class QueuedOneTimeTick < QueuedTick
  def tick args
    @block.call args, self
    @is_complete = true
  end
end


$game = Game.new
def tick args
  $game.args = args
  $game.tick
end

$gtk.reset

Performance link

Sprites As Hash - main.rb link

# ./samples/09_performance/01_sprites_as_hash/app/main.rb

# Sprites represented as Hashes using the queue ~args.outputs.sprites~
# code up, but are the "slowest" to render.
# The reason for this is the access of the key in the Hash and also
# because the data args.outputs.sprites is cleared every tick.
def random_x args
  (args.grid.w.randomize :ratio) * -1
end

def random_y args
  (args.grid.h.randomize :ratio) * -1
end

def random_speed
  1 + (4.randomize :ratio)
end

def new_star args
  {
    x: (random_x args),
    y: (random_y args),
    w: 4, h: 4, path: 'sprites/tiny-star.png',
    s: random_speed
  }
end

def move_star args, star
  star.x += star[:s]
  star.y += star[:s]
  if star.x > args.grid.w || star.y > args.grid.h
    star.x = (random_x args)
    star.y = (random_y args)
    star[:s] = random_speed
  end
end

def tick args
  args.state.star_count ||= 0

  # sets console command when sample app initially opens
  if Kernel.global_tick_count == 0
    puts ""
    puts ""
    puts "========================================================="
    puts "* INFO: Sprites, Hashes"
    puts "* INFO: Please specify the number of sprites to render."
    args.gtk.console.set_command "reset_with count: 100"
  end

  # init
  if Kernel.tick_count == 0
    args.state.stars = args.state.star_count.map { |i| new_star args }
  end

  # update
  args.state.stars.each { |s| move_star args, s }

  # render
  args.outputs.sprites << args.state.stars
  args.outputs.background_color = [0, 0, 0]
  args.outputs.primitives << args.gtk.current_framerate_primitives
end

# resets game, and assigns star count given by user
def reset_with count: count
  $gtk.reset
  $gtk.args.state.star_count = count
end

Sprites As Entities - main.rb link

# ./samples/09_performance/02_sprites_as_entities/app/main.rb
# Sprites represented as Entities using the queue ~args.outputs.sprites~
# yields nicer access apis over Hashes, but require a bit more code upfront.
# The hash sample has to use star[:s] to get the speed of the star, but
# an entity can use .s instead.
def random_x args
  (args.grid.w.randomize :ratio) * -1
end

def random_y args
  (args.grid.h.randomize :ratio) * -1
end

def random_speed
  1 + (4.randomize :ratio)
end

def new_star args
  args.state.new_entity :star, {
    x: (random_x args),
    y: (random_y args),
    w: 4, h: 4,
    path: 'sprites/tiny-star.png',
    s: random_speed
  }
end

def move_star args, star
  star.x += star.s
  star.y += star.s
  if star.x > args.grid.w || star.y > args.grid.h
    star.x = (random_x args)
    star.y = (random_y args)
    star.s = random_speed
  end
end

def tick args
  args.state.star_count ||= 0

  # sets console command when sample app initially opens
  if Kernel.global_tick_count == 0
    puts ""
    puts ""
    puts "========================================================="
    puts "* INFO: Sprites, Open Entities"
    puts "* INFO: Please specify the number of sprites to render."
    args.gtk.console.set_command "reset_with count: 100"
  end

  # init
  if Kernel.tick_count == 0
    args.state.stars = args.state.star_count.map { |i| new_star args }
  end

  # update
  args.state.stars.each { |s| move_star args, s }

  # render
  args.outputs.sprites << args.state.stars
  args.outputs.background_color = [0, 0, 0]
  args.outputs.primitives << args.gtk.current_framerate_primitives
end

# resets game, and assigns star count given by user
def reset_with count: count
  $gtk.reset
  $gtk.args.state.star_count = count
end

Sprites As Strict Entities - main.rb link

# ./samples/09_performance/04_sprites_as_strict_entities/app/main.rb
# Sprites represented as StrictEntities using the queue ~args.outputs.sprites~
# yields apis access similar to Entities, but all properties that can be set on the
# entity must be predefined with a default value. Strict entities do not support the
# addition of new properties after the fact. They are more performant than OpenEntities
# because of this constraint.
def random_x args
  (args.grid.w.randomize :ratio) * -1
end

def random_y args
  (args.grid.h.randomize :ratio) * -1
end

def random_speed
  1 + (4.randomize :ratio)
end

def new_star args
  args.state.new_entity_strict(:star,
                               x: (random_x args),
                               y: (random_y args),
                               w: 4, h: 4,
                               path: 'sprites/tiny-star.png',
                               s: random_speed) do |entity|
    # invoke attr_sprite so that it responds to
    # all properties that are required to render a sprite
    entity.attr_sprite
  end
end

def move_star args, star
  star.x += star.s
  star.y += star.s
  if star.x > args.grid.w || star.y > args.grid.h
    star.x = (random_x args)
    star.y = (random_y args)
    star.s = random_speed
  end
end

def tick args
  args.state.star_count ||= 0

  # sets console command when sample app initially opens
  if Kernel.global_tick_count == 0
    puts ""
    puts ""
    puts "========================================================="
    puts "* INFO: Sprites, Strict Entities"
    puts "* INFO: Please specify the number of sprites to render."
    args.gtk.console.set_command "reset_with count: 100"
  end

  # init
  if Kernel.tick_count == 0
    args.state.stars = args.state.star_count.map { |i| new_star args }
  end

  # update
  args.state.stars.each { |s| move_star args, s }

  # render
  args.outputs.sprites << args.state.stars
  args.outputs.background_color = [0, 0, 0]
  args.outputs.primitives << args.gtk.current_framerate_primitives
end

# resets game, and assigns star count given by user
def reset_with count: count
  $gtk.reset
  $gtk.args.state.star_count = count
end

Sprites As Classes - main.rb link

# ./samples/09_performance/05_sprites_as_classes/app/main.rb
# Sprites represented as Classes using the queue ~args.outputs.sprites~.
# gives you full control of property declaration and method invocation.
# They are more performant than OpenEntities and StrictEntities, but more code upfront.
class Star
  attr_sprite

  def initialize grid
    @grid = grid
    @x = (rand @grid.w) * -1
    @y = (rand @grid.h) * -1
    @w    = 4
    @h    = 4
    @s    = 1 + (4.randomize :ratio)
    @path = 'sprites/tiny-star.png'
  end

  def move
    @x += @s
    @y += @s
    @x = (rand @grid.w) * -1 if @x > @grid.right
    @y = (rand @grid.h) * -1 if @y > @grid.top
  end
end

# calls methods needed for game to run properly
def tick args
  # sets console command when sample app initially opens
  if Kernel.global_tick_count == 0
    puts ""
    puts ""
    puts "========================================================="
    puts "* INFO: Sprites, Classes"
    puts "* INFO: Please specify the number of sprites to render."
    args.gtk.console.set_command "reset_with count: 100"
  end

  args.state.star_count ||= 0

  # init
  if Kernel.tick_count == 0
    args.state.stars = args.state.star_count.map { |i| Star.new args.grid }
  end

  # update
  args.state.stars.each(&:move)

  # render
  args.outputs.sprites << args.state.stars
  args.outputs.background_color = [0, 0, 0]
  args.outputs.primitives << args.gtk.current_framerate_primitives
end

# resets game, and assigns star count given by user
def reset_with count: count
  $gtk.reset
  $gtk.args.state.star_count = count
end

Static Sprites As Classes - main.rb link

# ./samples/09_performance/06_static_sprites_as_classes/app/main.rb
# Sprites represented as Classes using the queue ~args.outputs.static_sprites~.
# bypasses the queue behavior of ~args.outputs.sprites~. All instances are held
# by reference. You get better performance, but you are mutating state of held objects
# which is less functional/data oriented.
class Star
  attr_sprite

  def initialize grid
    @grid = grid
    @x = (rand @grid.w) * -1
    @y = (rand @grid.h) * -1
    @w    = 4
    @h    = 4
    @s    = 1 + (4.randomize :ratio)
    @path = 'sprites/tiny-star.png'
  end

  def move
    @x += @s
    @y += @s
    @x = (rand @grid.w) * -1 if @x > @grid.right
    @y = (rand @grid.h) * -1 if @y > @grid.top
  end
end

# calls methods needed for game to run properly
def tick args
  # sets console command when sample app initially opens
  if Kernel.global_tick_count == 0
    puts ""
    puts ""
    puts "========================================================="
    puts "* INFO: Static Sprites, Classes"
    puts "* INFO: Please specify the number of sprites to render."
    args.gtk.console.set_command "reset_with count: 100"
  end

  args.state.star_count ||= 0

  # init
  if Kernel.tick_count == 0
    args.state.stars = args.state.star_count.map { |i| Star.new args.grid }
    args.outputs.static_sprites << args.state.stars
  end

  # update
  args.state.stars.each(&:move)

  # render
  args.outputs.background_color = [0, 0, 0]
  args.outputs.primitives << args.gtk.current_framerate_primitives
end

# resets game, and assigns star count given by user
def reset_with count: count
  $gtk.reset
  $gtk.args.state.star_count = count
end

Static Sprites As Classes With Custom Drawing - main.rb link

# ./samples/09_performance/07_static_sprites_as_classes_with_custom_drawing/app/main.rb
# Sprites represented as Classes, with a draw_override method, and using the queue ~args.outputs.static_sprites~.
# is the fastest approach. This is comparable to what other game engines set as the default behavior.
# There are tradeoffs for all this speed if the creation of a full blown class, and bypassing
# functional/data-oriented practices.
class Star
  def initialize grid
    @grid = grid
    @x = (rand @grid.w) * -1
    @y = (rand @grid.h) * -1
    @w    = 4
    @h    = 4
    @s    = 1 + (4.randomize :ratio)
    @path = 'sprites/tiny-star.png'
  end

  def move
    @x += @s
    @y += @s
    @x = (rand @grid.w) * -1 if @x > @grid.right
    @y = (rand @grid.h) * -1 if @y > @grid.top
  end

  # if the object that is in args.outputs.sprites (or static_sprites)
  # respond_to? :draw_override, then the method is invoked giving you
  # access to the class used to draw to the canvas.
  def draw_override ffi_draw
    # first move then draw
    move

    # The argument order for ffi.draw_sprite is:
    # x, y, w, h, path
    ffi_draw.draw_sprite @x, @y, @w, @h, @path

    # The argument order for ffi_draw.draw_sprite_2 is (pass in nil for default value):
    # x, y, w, h, path,
    # angle, alpha

    # The argument order for ffi_draw.draw_sprite_3 is:
    # x, y, w, h,
    # path,
    # angle,
    # alpha, red_saturation, green_saturation, blue_saturation
    # tile_x, tile_y, tile_w, tile_h,
    # flip_horizontally, flip_vertically,
    # angle_anchor_x, angle_anchor_y,
    # source_x, source_y, source_w, source_h

    # The argument order for ffi_draw.draw_sprite_4 is:
    # x, y, w, h,
    # path,
    # angle,
    # alpha, red_saturation, green_saturation, blue_saturation
    # tile_x, tile_y, tile_w, tile_h,
    # flip_horizontally, flip_vertically,
    # angle_anchor_x, angle_anchor_y,
    # source_x, source_y, source_w, source_h,
    # blendmode_enum

    # The argument order for ffi_draw.draw_sprite_5 is:
    # x, y, w, h,
    # path,
    # angle,
    # alpha, red_saturation, green_saturation, blue_saturation
    # tile_x, tile_y, tile_w, tile_h,
    # flip_horizontally, flip_vertically,
    # angle_anchor_x, angle_anchor_y,
    # source_x, source_y, source_w, source_h,
    # blendmode_enum
    # anchor_x
    # anchor_y

    # The argument order for ffi_draw.draw_sprite_6 is:
    # x, y, w, h,
    # path,
    # angle,
    # alpha, red_saturation, green_saturation, blue_saturation
    # tile_x, tile_y, tile_w, tile_h,
    # flip_horizontally, flip_vertically,
    # angle_anchor_x, angle_anchor_y,
    # source_x, source_y, source_w, source_h,
    # blendmode_enum
    # anchor_x
    # anchor_y
    # scale_quality_enum
  end
end

# calls methods needed for game to run properly
def tick args
  # sets console command when sample app initially opens
  if Kernel.global_tick_count == 0
    puts ""
    puts ""
    puts "========================================================="
    puts "* INFO: Static Sprites, Classes, Draw Override"
    puts "* INFO: Please specify the number of sprites to render."
    args.gtk.console.set_command "reset_with count: 100"
  end

  args.state.star_count ||= 0

  # init
  if Kernel.tick_count == 0
    args.state.stars = args.state.star_count.map { |i| Star.new args.grid }
    args.outputs.static_sprites << args.state.stars
  end

  # render framerate
  args.outputs.background_color = [0, 0, 0]
  args.outputs.primitives << args.gtk.current_framerate_primitives
end

# resets game, and assigns star count given by user
def reset_with count: count
  $gtk.reset
  $gtk.args.state.star_count = count
end

Collision Limits - main.rb link

# ./samples/09_performance/08_collision_limits/app/main.rb
=begin

 Reminders:
 - find_all: Finds all elements of a collection that meet certain requirements.
   In this sample app, we're finding all bodies that intersect with the center body.

 - args.outputs.solids: An array. The values generate a solid.
   The parameters are [X, Y, WIDTH, HEIGHT, RED, GREEN, BLUE]
   For more information about solids, go to mygame/documentation/03-solids-and-borders.md.

 - args.outputs.labels: An array. The values generate a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGNMENT, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.

 - ARRAY#intersect_rect?: Returns true or false depending on if two rectangles intersect.

=end

# This code demonstrates moving objects that loop around once they exceed the scope of the screen,
# which has dimensions of 1280 by 720, and also detects collisions between objects called "bodies".

def body_count num
  $gtk.args.state.other_bodies = num.map { [1280 * rand, 720 * rand, 10, 10] } # other_bodies set using num collection
end

def tick args

  # Center body's values are set using an array
  # Map is used to set values of 5000 other bodies
  # All bodies that intersect with center body are stored in collisions collection
  args.state.center_body  ||= { x: 640 - 100, y: 360 - 100, w: 200, h: 200 } # calculations done to place body in center
  args.state.other_bodies ||= 5000.map do
    { x: 1280 * rand,
      y: 720 * rand,
      w: 2,
      h: 2,
      path: :pixel,
      r: 0,
      g: 0,
      b: 0 }
  end # 2000 bodies given random position on screen

  # finds all bodies that intersect with center body, stores them in collisions
  collisions = args.state.other_bodies.find_all { |b| b.intersect_rect? args.state.center_body }

  args.borders << args.state.center_body # outputs center body as a black border

  # transparency changes based on number of collisions; the more collisions, the redder (more transparent) the box becomes
  args.sprites  << { x: args.state.center_body.x,
                     y: args.state.center_body.y,
                     w: args.state.center_body.w,
                     h: args.state.center_body.h,
                     path: :pixel,
                     a: collisions.length.idiv(2), # alpha value represents the number of collisions that occured
                     r: 255,
                     g: 0,
                     b: 0 } # center body is red solid
  args.sprites  << args.state.other_bodies # other bodies are output as (black) solids, as well

  args.labels  << [10, 30, args.gtk.current_framerate.to_sf] # outputs frame rate in bottom left corner

  # Bodies are returned to bottom left corner if positions exceed scope of screen
  args.state.other_bodies.each do |b| # for each body in the other_bodies collection
    b.x += 5 # x and y are both incremented by 5
    b.y += 5
    b.x = 0 if b.x > 1280 # x becomes 0 if star exceeds scope of screen (goes too far right)
    b.y = 0 if b.y > 720 # y becomes 0 if star exceeds scope of screen (goes too far up)
  end
end

# Resets the game.
$gtk.reset

Collision Limits Aabb - main.rb link

# ./samples/09_performance/09_collision_limits_aabb/app/main.rb
def tick args
  args.state.id_seed    ||= 1
  args.state.bullets    ||= []
  args.state.terrain    ||= [
    {
      x: 40, y: 0, w: 1200, h: 40, path: :pixel, r: 0, g: 0, b: 0
    },
    {
      x: 1240, y: 0, w: 40, h: 720, path: :pixel, r: 0, g: 0, b: 0
    },
    {
      x: 0, y: 0, w: 40, h: 720, path: :pixel, r: 0, g: 0, b: 0
    },
    {
      x: 40, y: 680, w: 1200, h: 40, path: :pixel, r: 0, g: 0, b: 0
    },

    {
      x: 760, y: 420, w: 180, h: 40, path: :pixel, r: 0, g: 0, b: 0
    },
    {
      x: 720, y: 420, w: 40, h: 100, path: :pixel, r: 0, g: 0, b: 0
    },
    {
      x: 940, y: 420, w: 40, h: 100, path: :pixel, r: 0, g: 0, b: 0
    },

    {
      x: 660, y: 220, w: 280, h: 40, path: :pixel, r: 0, g: 0, b: 0
    },
    {
      x: 620, y: 220, w: 40, h: 100, path: :pixel, r: 0, g: 0, b: 0
    },
    {
      x: 940, y: 220, w: 40, h: 100, path: :pixel, r: 0, g: 0, b: 0
    },

    {
      x: 460, y: 40, w: 280, h: 40, path: :pixel, r: 0, g: 0, b: 0
    },
    {
      x: 420, y: 40, w: 40, h: 100, path: :pixel, r: 0, g: 0, b: 0
    },
    {
      x: 740, y: 40, w: 40, h: 100, path: :pixel, r: 0, g: 0, b: 0
    },
  ]

  if args.inputs.keyboard.space
      b = {
        id: args.state.id_seed,
        x: 60,
        y: 60,
        w: 10,
        h: 10,
        dy: rand(20) + 10,
        dx: rand(20) + 10,
        path: 'sprites/square/blue.png'
      }

      args.state.bullets << b # if b.id == 122

      args.state.id_seed += 1
  end

  terrain = args.state.terrain

  args.state.bullets.each do |b|
    next if b.still
    # if b.still
    #   x_dir = if rand > 0.5
    #             -1
    #           else
    #             1
    #           end

    #   y_dir = if rand > 0.5
    #             -1
    #           else
    #             1
    #           end

    #   b.dy = rand(20) + 10 * x_dir
    #   b.dx = rand(20) + 10 * y_dir
    #   b.still = false
    #   b.on_floor = false
    # end

    if b.on_floor
      b.dx *= 0.9
    end

    b.x += b.dx

    collision_x = args.geometry.find_intersect_rect(b, terrain)

    if collision_x
      if b.dx > 0
        b.x = collision_x.x - b.w
      elsif b.dx < 0
        b.x = collision_x.x + collision_x.w
      end
      b.dx *= -0.8
    end

    b.dy -= 0.25
    b.y += b.dy

    collision_y = args.geometry.find_intersect_rect(b, terrain)

    if collision_y
      if b.dy > 0
        b.y = collision_y.y - b.h
      elsif b.dy < 0
        b.y = collision_y.y + collision_y.h
      end

      if b.dy < 0 && b.dy.abs < 1
        b.on_floor = true
      end

      b.dy *= -0.8
    end

    if b.on_floor && (b.dy.abs + b.dx.abs) < 0.1
      b.still = true
    end
  end

  args.outputs.labels << { x: 60, y: 60.from_top, text: "Hold space bar to add squares." }
  args.outputs.labels << { x: 60, y: 90.from_top, text: "FPS: #{args.gtk.current_framerate.to_sf}" }
  args.outputs.labels << { x: 60, y: 120.from_top, text: "Count: #{args.state.bullets.length}" }
  args.outputs.borders << args.state.terrain
  args.outputs.sprites << args.state.bullets
end

# $gtk.reset

Collision Limits Find Single - main.rb link

# ./samples/09_performance/09_collision_limits_find_single/app/main.rb
def tick args
  if args.state.should_reset_framerate_calculation
    args.gtk.reset_framerate_calculation
    args.state.should_reset_framerate_calculation = nil
  end

  if !args.state.rects
    args.state.rects = []
    add_10_000_random_rects args
  end

  args.state.player_rect ||= { x: 640 - 20, y: 360 - 20, w: 40, h: 40 }
  args.state.collision_type ||= :using_lambda

  if Kernel.tick_count == 0
    generate_scene args, args.state.quad_tree
  end

  # inputs
  # have a rectangle that can be moved around using arrow keys
  args.state.player_rect.x += args.inputs.left_right * 4
  args.state.player_rect.y += args.inputs.up_down * 4

  if args.inputs.mouse.click
    add_10_000_random_rects args
    args.state.should_reset_framerate_calculation = true
  end

  if args.inputs.keyboard.key_down.tab
    if args.state.collision_type == :using_lambda
      args.state.collision_type = :using_while_loop
    elsif args.state.collision_type == :using_while_loop
      args.state.collision_type = :using_find_intersect_rect
    elsif args.state.collision_type == :using_find_intersect_rect
      args.state.collision_type = :using_lambda
    end
    args.state.should_reset_framerate_calculation = true
  end

  # calc
  if args.state.collision_type == :using_lambda
    args.state.current_collision = args.state.rects.find { |r| r.intersect_rect? args.state.player_rect }
  elsif args.state.collision_type == :using_while_loop
    args.state.current_collision = nil
    idx = 0
    l = args.state.rects.length
    rects = args.state.rects
    player = args.state.player_rect
    while idx < l
      if rects[idx].intersect_rect? player
        args.state.current_collision = rects[idx]
        break
      end
      idx += 1
    end
  else
    args.state.current_collision = args.geometry.find_intersect_rect args.state.player_rect, args.state.rects
  end

  # render
  render_instructions args
  args.outputs.sprites << { x: 0, y: 0, w: 1280, h: 720, path: :scene }

  if args.state.current_collision
    args.outputs.sprites << args.state.current_collision.merge(path: :pixel, r: 255, g: 0, b: 0)
  end

  args.outputs.sprites << args.state.player_rect.merge(path: :pixel, a: 80, r: 0, g: 255, b: 0)
  args.outputs.labels  << {
    x: args.state.player_rect.x + args.state.player_rect.w / 2,
    y: args.state.player_rect.y + args.state.player_rect.h / 2,
    text: "player",
    alignment_enum: 1,
    vertical_alignment_enum: 1,
    size_enum: -4
  }

end

def add_10_000_random_rects args
  add_rects args, 10_000.map { { x: rand(1080) + 100, y: rand(520) + 100 } }
end

def add_rects args, points
  args.state.rects.concat(points.map { |point| { x: point.x, y: point.y, w: 5, h: 5 } })
  # args.state.quad_tree = args.geometry.quad_tree_create args.state.rects
  generate_scene args, args.state.quad_tree
end

def add_rect args, x, y
  args.state.rects << { x: x, y: y, w: 5, h: 5 }
  # args.state.quad_tree = args.geometry.quad_tree_create args.state.rects
  generate_scene args, args.state.quad_tree
end

def generate_scene args, quad_tree
  args.outputs[:scene].w = 1280
  args.outputs[:scene].h = 720
  args.outputs[:scene].solids << { x: 0, y: 0, w: 1280, h: 720, r: 255, g: 255, b: 255 }
  args.outputs[:scene].sprites << args.state.rects.map { |r| r.merge(path: :pixel, r: 0, g: 0, b: 255) }
end

def render_instructions args
  args.outputs.primitives << { x:  0, y: 90.from_top, w: 1280, h: 100, r: 0, g: 0, b: 0, a: 200 }.solid!
  args.outputs.labels << { x: 10, y: 10.from_top, r: 255, g: 255, b: 255, size_enum: -2, text: "Click to add 10,000 random rects. Tab to change collision algorithm." }
  args.outputs.labels << { x: 10, y: 40.from_top, r: 255, g: 255, b: 255, size_enum: -2, text: "Algorithm: #{args.state.collision_type}" }
  args.outputs.labels << { x: 10, y: 55.from_top, r: 255, g: 255, b: 255, size_enum: -2, text: "Rect Count: #{args.state.rects.length}" }
  args.outputs.labels << { x: 10, y: 70.from_top, r: 255, g: 255, b: 255, size_enum: -2, text: "FPS: #{args.gtk.current_framerate.to_sf}" }
end

Collision Limits Many To Many - main.rb link

# ./samples/09_performance/09_collision_limits_many_to_many/app/main.rb
class Square
  attr_sprite

  def initialize x, y
    @x    = x
    @y    = y
    @w    = 8
    @h    = 8
    @path = 'sprites/square/blue.png'
    @dir = if x < 640
             -1.0
           else
             1.0
           end
  end

  def reset_collision
    @path = "sprites/square/blue.png"
  end

  def mark_collision
    @path = 'sprites/square/red.png'
  end

  def move
    @dir  = -1.0 if (@x + @w >= 1280) && @dir ==  1.0
    @dir  =  1.0 if (@x      <=    0) && @dir == -1.0
    @x   += @dir
  end
end

def generate_random_squares args, center_x, center_y
  100.times do
    angle = rand 360
    distance = rand(200) + 20
    x = center_x + angle.vector_x * distance
    y = center_y + angle.vector_y * distance
    if x > 0 && x < 1280 && y < 720 && y > 0
      args.state.squares << Square.new(x, y)
    end
  end

  args.outputs.static_sprites.clear
  args.outputs.static_sprites << args.state.squares
  args.state.square_count = args.state.squares.length
end

def tick args
  args.state.squares ||= []

  if Kernel.tick_count == 0
    generate_random_squares args, 640, 360
  end

  if args.inputs.mouse.click
    generate_random_squares args, args.inputs.mouse.x, args.inputs.mouse.y
  end

  Array.each(args.state.squares) do |s|
    s.reset_collision
    s.move
  end

  Geometry.each_intersect_rect(args.state.squares, args.state.squares) do |a, b|
    a.mark_collision
    b.mark_collision
  end

  args.outputs.background_color = [0, 0, 0]
  args.outputs.watch "FPS: #{GTK.current_framerate.to_sf}"
  args.outputs.watch "Square Count: #{args.state.square_count.to_i}"
  args.outputs.watch "Instructions: click to add squares."
end

Ui Controls link

Checkboxes - main.rb link

# ./samples/09_ui_controls/01_checkboxes/app/main.rb
def tick args
  # use layout apis to position check boxes
  args.state.checkboxes ||= [
    args.layout.rect(row: 0, col: 0, w: 1, h: 1).merge(id: :option1, text: "Option 1", checked: false, changed_at: -120),
    args.layout.rect(row: 1, col: 0, w: 1, h: 1).merge(id: :option1, text: "Option 2", checked: false, changed_at: -120),
    args.layout.rect(row: 2, col: 0, w: 1, h: 1).merge(id: :option1, text: "Option 3", checked: false, changed_at: -120),
    args.layout.rect(row: 3, col: 0, w: 1, h: 1).merge(id: :option1, text: "Option 4", checked: false, changed_at: -120),
  ]

  # check for click of checkboxes
  if args.inputs.mouse.click
    args.state.checkboxes.find_all do |checkbox|
      args.inputs.mouse.inside_rect? checkbox
    end.each do |checkbox|
      # mark checkbox value
      checkbox.checked = !checkbox.checked
      # set the time the checkbox was changed
      checkbox.changed_at = Kernel.tick_count
    end
  end

  # render checkboxes
  args.outputs.primitives << args.state.checkboxes.map do |checkbox|
    # baseline prefab for checkbox
    prefab = {
      x: checkbox.x,
      y: checkbox.y,
      w: checkbox.w,
      h: checkbox.h
    }

    # label for checkbox centered vertically
    label = {
      x: checkbox.x + checkbox.w + 10,
      y: checkbox.y + checkbox.h / 2,
      text: checkbox.text,
      alignment_enum: 0,
      vertical_alignment_enum: 1
    }

    # rendering if checked or not
    if checkbox.checked
      # fade in
      a = 255 * args.easing.ease(checkbox.changed_at, Kernel.tick_count, 30, :smooth_stop_quint)

      [
        label,
        prefab.merge(primitive_marker: :solid, a: a),
        prefab.merge(primitive_marker: :border)
      ]
    else
      # fade out
      a = 255 * args.easing.ease(checkbox.changed_at, Kernel.tick_count, 30, :smooth_stop_quint, :flip)

      [
        label,
        prefab.merge(primitive_marker: :solid, a: a),
        prefab.merge(primitive_marker: :border)
      ]
    end
  end
end

Menu Navigation - main.rb link

# ./samples/09_ui_controls/02_menu_navigation/app/main.rb
class Game
  attr_gtk

  def tick
    defaults
    calc
    render
  end

  def render
    outputs.primitives << state.selection_point.merge(w: state.menu.button_w + 8,
                                                      h: state.menu.button_h + 8,
                                                      a: 128,
                                                      r: 0,
                                                      g: 200,
                                                      b: 100,
                                                      path: :solid,
                                                      anchor_x: 0.5,
                                                      anchor_y: 0.5)

    outputs.primitives << state.menu.buttons.map(&:primitives)
  end

  def calc_directional_input
    return if state.input_debounce.elapsed_time < 10
    return if !inputs.directional_vector
    state.input_debounce = Kernel.tick_count

    state.selected_button = Geometry::rect_navigate(
      rect: state.selected_button,
      rects: state.menu.buttons,
      left_right: inputs.left_right,
      up_down: inputs.up_down,
      wrap_x: true,
      wrap_y: true,
      using: lambda { |e| e.rect }
    )
  end

  def calc_mouse_input
    return if !inputs.mouse.moved
    hovered_button = state.menu.buttons.find { |b| Geometry::intersect_rect? inputs.mouse, b.rect }
    if hovered_button
      state.selected_button = hovered_button
    end
  end

  def calc
    target_point = state.selected_button.rect.center
    state.selection_point.x = state.selection_point.x.lerp(target_point.x, 0.25)
    state.selection_point.y = state.selection_point.y.lerp(target_point.y, 0.25)
    calc_directional_input
    calc_mouse_input
  end

  def defaults
    if !state.menu
      state.menu = {
        button_cell_w: 2,
        button_cell_h: 1,
      }
      state.menu.button_w = Layout::rect(w: 2).w
      state.menu.button_h = Layout::rect(h: 1).h
      state.menu.buttons = [
        menu_prefab(id: :item_1, text: "Item 1", row: 0, col: 0, w: state.menu.button_cell_w, h: state.menu.button_cell_h),
        menu_prefab(id: :item_2, text: "Item 2", row: 0, col: 2, w: state.menu.button_cell_w, h: state.menu.button_cell_h),
        menu_prefab(id: :item_3, text: "Item 3", row: 0, col: 4, w: state.menu.button_cell_w, h: state.menu.button_cell_h),
        menu_prefab(id: :item_4, text: "Item 4", row: 1, col: 0, w: state.menu.button_cell_w, h: state.menu.button_cell_h),
        menu_prefab(id: :item_5, text: "Item 5", row: 1, col: 2, w: state.menu.button_cell_w, h: state.menu.button_cell_h),
        menu_prefab(id: :item_6, text: "Item 6", row: 1, col: 4, w: state.menu.button_cell_w, h: state.menu.button_cell_h),
        menu_prefab(id: :item_7, text: "Item 7", row: 2, col: 0, w: state.menu.button_cell_w, h: state.menu.button_cell_h),
        menu_prefab(id: :item_8, text: "Item 8", row: 2, col: 2, w: state.menu.button_cell_w, h: state.menu.button_cell_h),
        menu_prefab(id: :item_9, text: "Item 9", row: 2, col: 4, w: state.menu.button_cell_w, h: state.menu.button_cell_h),
      ]
    end

    state.selected_button ||= state.menu.buttons.first
    state.selection_point ||= { x: state.selected_button.rect.center.x,
                                y: state.selected_button.rect.center.y }
    state.input_debounce  ||= 0
  end

  def menu_prefab id:, text:, row:, col:, w:, h:;
    rect = Layout::rect(row: row, col: col, w: w, h: h)
    {
      id: id,
      row: row,
      col: col,
      text: text,
      rect: rect,
      primitives: [
        rect.merge(primitive_marker: :border),
        rect.center.merge(text: text, anchor_x: 0.5, anchor_y: 0.5)
      ]
    }
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

def reset args
  $game = nil
end

$gtk.reset

Radial Menu - main.rb link

# ./samples/09_ui_controls/03_radial_menu/app/main.rb
class Game
  attr_gtk

  def tick
    defaults
    calc
    render
  end

  def defaults
    state.menu_items = [
      { id: :item_1, text: "Item 1" },
      { id: :item_2, text: "Item 2" },
      { id: :item_3, text: "Item 3" },
      { id: :item_4, text: "Item 4" },
      { id: :item_5, text: "Item 5" },
      { id: :item_6, text: "Item 6" },
      { id: :item_7, text: "Item 7" },
      { id: :item_8, text: "Item 8" },
      { id: :item_9, text: "Item 9" },
    ]

    state.menu_status     ||= :hidden
    state.menu_radius     ||= 200
    state.menu_status_at  ||= -1000
  end

  def calc
    state.menu_items.each_with_index do |item, i|
      item.menu_angle = 90 + (360 / state.menu_items.length) * i
      item.menu_angle_range = 360 / state.menu_items.length - 10
    end

    state.menu_items.each do |item|
      item.rect = Geometry.rect_props x: 640 + item.menu_angle.vector_x * state.menu_radius - 50,
                                      y: 360 + item.menu_angle.vector_y * state.menu_radius - 25,
                                      w: 100,
                                      h: 50

      item.circle = { x: item.rect.x + item.rect.w / 2, y: item.rect.y + item.rect.h / 2, radius: item.rect.w / 2 }
    end

    show_menu_requested = false
    if state.menu_status == :hidden
      show_menu_requested = true if inputs.controller_one.key_down.a
      show_menu_requested = true if inputs.mouse.click
    end

    hide_menu_requested = false
    if state.menu_status == :shown
      hide_menu_requested = true if inputs.controller_one.key_down.b
      hide_menu_requested = true if inputs.mouse.click && !state.hovered_menu_item
    end

    if state.menu_status == :shown && state.hovered_menu_item && (inputs.mouse.click || inputs.controller_one.key_down.a)
      GTK.notify! "You selected #{state.hovered_menu_item[:text]}"
    elsif show_menu_requested
      state.menu_status = :shown
      state.menu_status_at = Kernel.tick_count
    elsif hide_menu_requested
      state.menu_status = :hidden
      state.menu_status_at = Kernel.tick_count
    end

    state.hovered_menu_item = state.menu_items.find { |item| Geometry.point_inside_circle? inputs.mouse, item.circle }

    if inputs.controller_one.active && inputs.controller_one.left_analog_active?(threshold_perc: 0.5)
      state.hovered_menu_item = state.menu_items.find do |item|
        Geometry.angle_within_range? inputs.controller_one.left_analog_angle, item.menu_angle, item.menu_angle_range
      end
    end
  end

  def menu_prefab item, perc
    dx = item.rect.center.x - 640
    x = 640 + dx * perc
    dy = item.rect.center.y - 360
    y = 360 + dy * perc
    Geometry.rect_props item.rect.merge x: x - item.rect.w / 2, y: y - item.rect.h / 2
  end

  def ring_prefab x_center, y_center, radius, precision:, color: nil
    color ||= { r: 0, g: 0, b: 0, a: 255 }
    pi = Math::PI
    lines = []

    precision.map do |i|
      theta = 2.0 * pi * i / precision
      next_theta = 2.0 * pi * (i + 1) / precision

      {
        x: x_center + radius * theta.cos_r,
        y: y_center + radius * theta.sin_r,
        x2: x_center + radius * next_theta.cos_r,
        y2: y_center + radius * next_theta.sin_r,
        **color
      }
    end
  end

  def circle_prefab x_center, y_center, radius, precision:, color: nil
    color ||= { r: 0, g: 0, b: 0, a: 255 }
    pi = Math::PI
    lines = []

    # Indie/Pro Only (uses triangles)
    precision.map do |i|
      theta = 2.0 * pi * i / precision
      next_theta = 2.0 * pi * (i + 1) / precision

      {
        x:  x_center + radius * theta.cos_r,
        y:  y_center + radius * theta.sin_r,
        x2: x_center + radius * next_theta.cos_r,
        y2: y_center + radius * next_theta.sin_r,
        y3: y_center,
        x3: x_center,
        source_x:  0,
        source_y:  0,
        source_x2: 0,
        source_y2: radius,
        source_x3: radius,
        source_y3: 0,
        path:      :solid,
        **color,
      }
    end
  end

  def render
    outputs.debug.watch "Controller"
    outputs.debug.watch pretty_format(inputs.controller_one.to_h)

    outputs.debug.watch "Mouse"
    outputs.debug.watch pretty_format(inputs.mouse.to_h)

    # outputs.debug.watch "Mouse"
    # outputs.debug.watch pretty_format(inputs.mouse)
    outputs.primitives << { x: 640, y: 360, w: 10, h: 10, path: :solid, r: 128, g: 0, b: 0, a: 128, anchor_x: 0.5, anchor_y: 0.5 }

    if state.menu_status == :shown
      perc = Easing.ease(state.menu_status_at, Kernel.tick_count, 30, :smooth_stop_quart)
    else
      perc = Easing.ease(state.menu_status_at, Kernel.tick_count, 30, :smooth_stop_quart, :flip)
    end

    outputs.primitives << state.menu_items.map do |item|
      a = 255 * perc
      color = { r: 128, g: 128, b: 128, a: a }
      if state.hovered_menu_item == item
        color = { r: 80, g: 128, b: 80, a: a }
      end

      menu = menu_prefab(item, perc)

      if state.menu_status == :shown
        ring = ring_prefab(menu.center.x, menu.center.y, item.circle.radius, precision: 30, color: color.merge(a: 128))
        circle = circle_prefab(menu.center.x, menu.center.y, item.circle.radius, precision: 30, color: color.merge(a: 128))
      end

      [
        ring,
        circle,
        menu.merge(path: :solid, **color),
        menu.center.merge(text: item.text, a: a, anchor_x: 0.5, anchor_y: 0.5)
      ]
    end
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

def reset
  $game = nil
end

GTK.reset

Scroll View - main.rb link

# ./samples/09_ui_controls/03_scroll_view/app/main.rb
class ScrollView
  attr_gtk

  attr :y_offset, :rect, :clicked_items, :target_y_offset

  def initialize row:, col:, w:, h:;
    @items = []
    @clicked_items = []
    @y_offset = 0
    @scroll_view_dy = 0
    @rect = Layout.rect row: row,
                        col: col,
                        w: w,
                        h: h,
                        include_row_gutter: true,
                        include_col_gutter: true
    @primitives = []
  end

  def add_item prefab
    raise "prefab must be a Hash" unless prefab.is_a? Hash
    @items << prefab
  end

  def content_height
    lowest_item = @items.min_by { |primitive| primitive.y } || { x: 0, y: 0 }
    h = @rect.h

    if lowest_item
      h -= lowest_item.y - Layout.gutter
    end

    h
  end

  def y_offset_bottom_limit
    -80
  end

  def y_offset_top_limit
    content_height - @rect.h + @rect.y + 80
  end

  def tick_inputs
    @clicked_items = []

    if inputs.mouse.down
      @last_mouse_held_y = inputs.mouse.y
      @last_mouse_held_y_diff = 0
    elsif inputs.mouse.held
      @last_mouse_held_y ||= inputs.mouse.y
      @last_mouse_held_y_diff ||= 0
      @last_mouse_held_y_diff = inputs.mouse.y - @last_mouse_held_y
      @last_mouse_held_y = inputs.mouse.y
    end

    if inputs.mouse.down
      @mouse_down_at = Kernel.tick_count
      @mouse_down_y = inputs.mouse.y
      if @scroll_view_dy.abs < 7
        @maybe_click = true
      else
        @maybe_click = false
      end

      @scroll_view_dy = 0
    elsif inputs.mouse.held
      @target_y_offset = @y_offset + (inputs.mouse.y - @mouse_down_y) * 2
      @mouse_down_y = inputs.mouse.y
    elsif inputs.mouse.up
      @target_y_offset = nil
      @mouse_up_at = Kernel.tick_count
      @mouse_up_y = inputs.mouse.y

      if @maybe_click && (@last_mouse_held_y_diff).abs <= 1 && (@mouse_down_at - @mouse_up_at).abs < 12
        if inputs.mouse.y - 20 > @rect.y && inputs.mouse.y < (@rect.y + @rect.h - 20)
          @clicked_items = offset_items.reject { |primitive| !primitive.w || !primitive.h }
                                       .find_all { |primitive| inputs.mouse.inside_rect? primitive }
        end
      else
        @scroll_view_dy += @last_mouse_held_y_diff
      end
      @mouse_down_at = nil
      @mouse_up_at = nil
    end

    if inputs.keyboard.key_down.page_down
      if @scroll_view_dy >= 0
        @scroll_view_dy += 5
      else
        @scroll_view_dy = @scroll_view_dy.lerp(0, 1)
      end
    elsif inputs.keyboard.key_down.page_up
      if @scroll_view_dy <= 0
        @scroll_view_dy -= 5
      else
        @scroll_view_dy = @scroll_view_dy.lerp(0, 1)
      end
    end

    if inputs.mouse.wheel
      if inputs.mouse.wheel.inverted
        @scroll_view_dy -= inputs.mouse.wheel.y
      else
        @scroll_view_dy += inputs.mouse.wheel.y
      end
    end

  end

  def tick
    if @target_y_offset
      if @target_y_offset < y_offset_bottom_limit
        @y_offset = @y_offset.lerp @target_y_offset, 0.05
      elsif @target_y_offset > y_offset_top_limit
        @y_offset = @y_offset.lerp @target_y_offset, 0.05
      else
        @y_offset = @y_offset.lerp @target_y_offset, 0.5
      end
      @target_y_offset = nil if @y_offset.round == @target_y_offset.round
      @scroll_view_dy = 0
    end

    tick_inputs

    @y_offset += @scroll_view_dy

    if @y_offset < 0
      if inputs.mouse.held
        # if @y_offset < -80
        #   @y_offset = -80
        # end
      else
        @y_offset = @y_offset.lerp(0, 0.2)
      end
    end

    if content_height <= (@rect.h - @rect.y)
      @y_offset = 0
      @scroll_view_dy = 0
    elsif @y_offset > content_height - @rect.h + @rect.y
      if inputs.mouse.held
        # if @y_offset > (content_height - @rect.h + @rect.y) + 80
        #   @y_offset = (content_height - @rect.h + @rect.y) + 80
        # end
      else
        @y_offset = @y_offset.lerp(content_height - @rect.h + @rect.y, 0.2)
      end
    end
    @scroll_view_dy *= 0.95
    @scroll_view_dy = @scroll_view_dy.round(2)
  end

  def items
    @items
  end

  def offset_items
    @items.map { |primitive| primitive.merge(y: primitive.y + @y_offset) }
  end

  def prefab
    outputs[:scroll_view].w = Grid.w
    outputs[:scroll_view].h = Grid.h
    outputs[:scroll_view].background_color = [0, 0, 0, 0]

    outputs[:scroll_view_content].w = Grid.w
    outputs[:scroll_view_content].h = Grid.h
    outputs[:scroll_view_content].background_color = [0, 0, 0, 0]

    outputs[:scroll_view_content].primitives << offset_items

    outputs[:scroll_view].primitives << {
      x: @rect.x,
      y: @rect.y,
      w: @rect.w,
      h: @rect.h,
      source_x: @rect.x,
      source_y: @rect.y,
      source_w: @rect.w,
      source_h: @rect.h,
      path: :scroll_view_content
    }

    outputs[:scroll_view].primitives << [
      { x: @rect.x,
        y: @rect.y,
        w: @rect.w,
        h: @rect.h,
        primitive_marker: :border,
        r: 128,
        g: 128,
        b: 128 },
    ]

    { x: 0,
      y: 0,
      w: Grid.w,
      h: Grid.h,
      path: :scroll_view }
  end
end

class Game
  attr_gtk

  attr :scroll_view

  def initialize
    @scroll_view = ScrollView.new row: 2, col: 0, w: 12, h: 20
  end

  def defaults
    state.scroll_view_dy             ||= 0
    state.scroll_view_offset_y       ||= 0
  end

  def calc
    if Kernel.tick_count == 0
      80.times do |i|
        @scroll_view.add_item Layout.rect(row: 2 + i * 2, col: 0, w: 2, h: 2).merge(id: "item_#{i}_square_1".to_sym, path: :solid, r: 32 + i * 2, g: 32, b: 32)
        @scroll_view.add_item Layout.rect(row: 2 + i * 2, col: 0, w: 2, h: 2).center.merge(text: "item #{i}", anchor_x: 0.5, anchor_y: 0.5, r: 255, g: 255, b: 255)
        @scroll_view.add_item Layout.rect(row: 2 + i * 2, col: 2, w: 2, h: 2).merge(id: "item_#{i}_square_2".to_sym, path: :solid, r: 64 + i * 2, g: 64, b: 64)
      end
    end

    @scroll_view.args = args
    @scroll_view.tick

    if @scroll_view.clicked_items.length > 0
      puts @scroll_view.clicked_items
    end
  end

  def render
    outputs.primitives << @scroll_view.prefab
  end

  def tick
    defaults
    calc
    render
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

def reset args
  $game = nil
end

GTK.reset

Accessiblity For The Blind - main.rb link

# ./samples/09_ui_controls/04_accessiblity_for_the_blind/app/main.rb
def tick args
  # create three buttons
  args.state.button_1 ||= { x: 0, y: 640, w: 100, h: 50 }
  args.state.button_1_label ||= { x: 50,
                                  y: 665,
                                  text: "button 1",
                                  anchor_x: 0.5,
                                  anchor_y: 0.5 }

  args.state.button_2 ||= { x: 104, y: 640, w: 100, h: 50 }
  args.state.button_2_label ||= { x: 154,
                                  y: 665,
                                  text: "button 2",
                                  anchor_x: 0.5,
                                  anchor_y: 0.5 }

  args.state.button_3 ||= { x: 208, y: 640, w: 100, h: 50 }
  args.state.button_3_label ||= { x: 258,
                                  y: 665,
                                  text: "button 3",
                                  anchor_x: 0.5,
                                  anchor_y: 0.5 }

  # create a label
  args.state.label_hello_world ||= { x: 640,
                                     y: 360,
                                     text: "hello world",
                                     anchor_x: 0.5,
                                     anchor_y: 0.5 }

  args.outputs.borders << args.state.button_1
  args.outputs.labels  << args.state.button_1_label

  args.outputs.borders << args.state.button_2
  args.outputs.labels  << args.state.button_2_label

  args.outputs.borders << args.state.button_3
  args.outputs.labels  << args.state.button_3_label

  args.outputs.labels  << args.state.label_hello_world

  # args.outputs.a11y is cleared every tick, internally the key
  # of the dictionary value is used to reference the interactable element.
  # the key can be a symbol or a string (everything get's converted to strings
  # beind the scenes)

  # =======================================
  # from the Console run $gtk.a11y_enable!
  # ctrl+r will disable a11y (or you can run $gtk.a11y_disable! in the console)
  # =======================================

  # with the a11y emulation enabled, you can only use left arrow, right arrow, and enter
  # when you press enter, DR converts the location to a mouse click
  args.outputs.a11y[:button_1] = {
    a11y_text: "button 1",
    a11y_trait: :button,
    x: args.state.button_1.x,
    y: args.state.button_1.y,
    w: args.state.button_1.w,
    h: args.state.button_1.h
  }

  args.outputs.a11y[:button_2] = {
    a11y_text: "button 2",
    a11y_trait: :button,
    x: args.state.button_2.x,
    y: args.state.button_2.y,
    w: args.state.button_2.w,
    h: args.state.button_2.h
  }

  args.outputs.a11y[:button_3] = {
    a11y_text: "button 3",
    a11y_trait: :button,
    x: args.state.button_3.x,
    y: args.state.button_3.y,
    w: args.state.button_3.w,
    h: args.state.button_3.h
  }

  args.outputs.a11y[:label_hello] = {
    a11y_text: "hello world",
    a11y_trait: :label,
    x: args.state.label_hello_world.x,
    y: args.state.label_hello_world.y,
    anchor_x: 0.5,
    anchor_y: 0.5,
  }

  # flash a notification for each respective button
  if args.inputs.mouse.click && args.inputs.mouse.inside_rect?(args.state.button_1)
    GTK.notify_extended! message: "Button 1 clicked", a: 255
    # you can use a11y to speak information
    args.outputs.a11y["notify button clicked"] = {
      a11y_text: "button 1 clicked",
      a11y_trait: :notification
    }
  end

  if args.inputs.mouse.click && args.inputs.mouse.inside_rect?(args.state.button_2)
    GTK.notify_extended! message: "Button 2 clicked", a: 255
  end

  if args.inputs.mouse.click && args.inputs.mouse.inside_rect?(args.state.button_3)
    GTK.notify_extended! message: "Button 3 clicked", a: 255
    # you can also use a11y to redirect focus to another control
    args.outputs.a11y["notify button clicked"] = {
      a11y_trait: :notification,
      a11y_notification_target: :label_hello
    }
  end
end

$gtk.reset

Advanced Debugging link

Unit Tests - main.rb link

# ./samples/10_advanced_debugging/03_unit_tests/app/main.rb

Unit Tests - benchmark_api_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/benchmark_api_tests.rb
def test_benchmark_api args, assert
  result = args.gtk.benchmark iterations: 100,
                              only_one: -> () {
                                r = 0
                                (1..100).each do |i|
                                  r += 1
                                end
                              }

  assert.equal! result.first_place.name, :only_one

  result = args.gtk.benchmark iterations: 100,
                              iterations_100: -> () {
                                r = 0
                                (1..100).each do |i|
                                  r += 1
                                end
                              },
                              iterations_50: -> () {
                                r = 0
                                (1..50).each do |i|
                                  r += 1
                                end
                              }

  assert.equal! result.first_place.name, :iterations_50

  result = args.gtk.benchmark iterations: 1,
                              iterations_100: -> () {
                                r = 0
                                (1..100).each do |i|
                                  r += 1
                                end
                              },
                              iterations_50: -> () {
                                r = 0
                                (1..50).each do |i|
                                  r += 1
                                end
                              }

  assert.equal! result.too_small_to_measure, true
end

Unit Tests - enumerable_class_function_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/enumerable_class_function_tests.rb
def test_hash_find_all args, assert
  h = {
    x: 100,
    y: 200,
    w: 10,
    h: 10
  }

  result_expected = h.find_all { |k, v| v == 100 }
  result_actual = Hash.find_all(h) { |k, v| v == 100 }
  assert.equal! result_expected, result_actual
end

def test_hash_merge args, assert
  a = {
    x: 100,
    y: 200,
    w: 10,
    h: 10
  }

  b = {
    r: 255,
    g: 255,
    b: 255
  }

  result_expected = a.merge b
  result_actual = Hash.merge a, b
  assert.equal! result_actual, result_expected, "class implementation, matches instance implemenation"
  assert.not_equal! a.object_id, result_actual.object_id, "new hash created for merge"
end

def test_hash_merge_bang args, assert
  a = {
    x: 100,
    y: 200,
    w: 10,
    h: 10
  }

  b = {
    r: 255,
    g: 255,
    b: 255
  }

  a_2 = {
    x: 100,
    y: 200,
    w: 10,
    h: 10
  }

  b_2 = {
    r: 255,
    g: 255,
    b: 255
  }

  result_expected = a.merge! b
  result_actual = Hash.merge! a_2, b_2
  assert.equal! result_actual, result_expected, "class implementation, matches instance implemenation"
  assert.equal! a_2.object_id, result_actual.object_id, "hash updated for merge!"
end

def test_hash_merge_with_block args, assert
  a = {
    x: 100,
    y: 200,
    w: 10,
    h: 10
  }

  b = {
    x: 500,
  }

  result_expected = a.merge(b) do |k, current_value, new_value|
    current_value + new_value
  end

  result_actual = Hash.merge(a, b) do
    |k, current_value, new_value|
    current_value + new_value
  end

  assert.equal! result_expected[:x], result_actual[:x]
end

def test_array_map args, assert
  a = [1, 2, 3]

  result_expected = a.map do |i| i**2 end
  result_actual = Array.map a do |i| i**2 end
  assert.equal! result_expected, result_actual
  assert.not_equal! a.object_id, result_actual.object_id
end

def test_array_map_with_destructoring args, assert
  a = [[1, 2], [3, 4]]
  result_expected = a.map do |x, y| x + y end
  result_actual = Array.map a do |x, y| x + y end
  assert.equal! result_expected, result_actual
  assert.not_equal! a.object_id, result_actual.object_id

  a = [[1, 2], [3, 4]]
  result_expected = a.map.with_index do |(x, y), i| x + y + i end
  result_actual = Array.map_with_index a do |(x, y), i| x + y + i end
  assert.equal! result_expected, result_actual
  assert.not_equal! a.object_id, result_actual.object_id
end

def test_array_map_bang args, assert
  a = [1, 2, 3]
  result_expected = a.map do |i| i**2 end
  result_actual = Array.map! a do |i| i**2 end
  assert.equal! result_expected, result_actual
  assert.equal! a.object_id, result_actual.object_id
end

def test_array_reject args, assert
  a = [1, 2, 3, 4, 5, 6]
  result_expected = a.reject do |i| i.even? end
  result_actual = Array.reject a do |i| i.even? end
  assert.equal! result_expected, result_actual
  assert.not_equal! a.object_id, result_actual.object_id
end

def test_array_reject_bang args, assert
  a = [1, 2, 3, 4, 5, 6]
  result_expected = a.reject do |i| i.even? end
  result_actual = Array.reject! a do |i| i.even? end
  assert.equal! result_expected, result_actual
  assert.equal! a.object_id, result_actual.object_id
end

def test_array_select args, assert
  a = [1, 2, 3, 4, 5, 6]
  result_expected = a.select do |i| i.even? end
  result_actual = Array.select a do |i| i.even? end
  assert.equal! result_expected, result_actual
  assert.not_equal! a.object_id, result_actual.object_id
end

def test_array_select_bang args, assert
  a = [1, 2, 3, 4, 5, 6]
  result_expected = a.select do |i| i.even? end
  result_actual = Array.select! a do |i| i.even? end
  assert.equal! result_expected, result_actual
  assert.equal! a.object_id, result_actual.object_id
end

def test_array_find_all args, assert
  a = [1, 2, 3, 4, 5, 6]
  result_expected = a.find_all do |i| i.even? end
  result_actual = Array.find_all a do |i| i.even? end
  assert.equal! result_expected, result_actual
  assert.not_equal! a.object_id, result_actual.object_id
end

def test_array_compact args, assert
  a = [1, nil, 3, false, 5, 6]
  result_expected = a.compact do |i| i.even? end
  result_actual = Array.compact a do |i| i.even? end
  assert.equal! result_expected, result_actual
  assert.not_equal! a.object_id, result_actual.object_id
end

def test_array_compact_bang args, assert
  a = 100.map { |i| i }.map { |i| i.even? ? i : nil }
  result_expected = a.compact do |i| i.even? end
  result_actual = Array.compact! a do |i| i.even? end
  assert.equal! result_expected, result_actual
  assert.equal! a.object_id, result_actual.object_id
end

def test_filter_map args, assert
  a = [1, 2, 3, 4, 5, 6]
  result_expected = a.filter_map do |i| i.even? ? i * 2 : nil end
  result_actual = Array.filter_map a do |i| i.even? ? i * 2 : nil end
  assert.equal! result_expected, result_actual
  assert.not_equal! a.object_id, result_actual.object_id
end

def test_flat_map args, assert
  a = 100.map.each_slice(2).to_a
  result_expected = a.flat_map do |i| i end
  result_actual = Array.flat_map a do |i| i end
  assert.equal! result_expected, result_actual
  assert.not_equal! a.object_id, result_actual.object_id
end

def test_array_each args, assert
  a = [1, 2, 3, 4, 5, 6]
  result_expected = []
  a.each do |i| result_expected << i end
  result_actual = []
  Array.each a do |i| result_actual << i end
  assert.equal! result_expected, result_actual

  a = [[1, 2], [3, 4], [5, 6]]
  result_expected = []
  a.each do |x, y| result_expected << x + y end
  result_actual = []
  Array.each a do |x, y| result_actual << x + y end
  assert.equal! result_expected, result_actual

  a = [1, 2, 3, 4, 5, 6]
  result_expected = []
  a.each_with_index do |n, i| result_expected << n - i end
  result_actual = []
  Array.each_with_index a do |n, i| result_actual << n - i end
  assert.equal! result_expected, result_actual

  a = [[1, 2], [3, 4], [5, 6]]
  result_expected = []
  a.each_with_index do |(x, y), i| result_expected << x + y + i end
  result_actual = []
  Array.each_with_index a do |(x, y), i| result_actual << x + y + i end
  assert.equal! result_expected, result_actual
end

def test_bench args, assert
  ary_numbers = 100.map { |i| i }.reverse.to_a
  ary_compact = 100.map { |i| i }.map { |i| i.even? ? i : nil }
  ary_flat_map = 100.map.each_slice(2).to_a

  functions = [
    { name: :map,        ary: ary_numbers, m: proc { |i| i / 2 } },
    { name: :map!,       ary: ary_numbers, m: proc { |i| i / 2 } },
    { name: :reject,     ary: ary_numbers, m: proc { |i| i.even? } },
    { name: :reject!,    ary: ary_numbers, m: proc { |i| i.even? } },
    { name: :find_all,   ary: ary_numbers, m: proc { |i| i.even? } },
    { name: :select,     ary: ary_numbers, m: proc { |i| i.even? } },
    { name: :select!,    ary: ary_numbers, m: proc { |i| i.even? } },
    { name: :filter_map, ary: ary_numbers, m: proc { |i| i.even? ? i * 2 : nil } },
    { name: :compact,    ary: ary_compact },
    { name: :compact!,   ary: ary_compact },
  ]

  functions.each do |fh|
    h = {
      iterations: 5000,
    }

    self_numbers = fh.ary.dup
    class_numbers = fh.ary.dup

    h["self_#{fh[:name]}".to_sym] = -> () {
      self_numbers.send(fh[:name], &fh[:m])
    }

    h["class_#{fh[:name]}".to_sym] = -> () {
      Array.send(fh[:name], class_numbers, &fh[:m])
    }

    results = GTK.benchmark(**h)
    assert.true! results.first_place.name.to_s.start_with?("class_"), "Class method #{fh[:name]} is faster"
  end

  self_numbers = ary_numbers.dup
  class_numbers = ary_numbers.dup
  results = GTK.benchmark iterations: 5000,
                          self_each: -> () { self_numbers.each { |i| i } },
                          class_each: -> () { Array.each(class_numbers) { |i| i } }

  self_flat_map = ary_flat_map.dup
  class_flat_map = ary_flat_map.dup
  results = GTK.benchmark iterations: 5000,
                          self_flat_map: -> () { self_flat_map.flat_map { |i| i } },
                          class_flat_map: -> () { Array.flat_map(class_flat_map) { |i| i } }

  assert.true! results.first_place.name.to_s.start_with?("class_"), "Class method each is faster"
end

Unit Tests - exception_raising_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/exception_raising_tests.rb
begin :shared
  class ExceptionalClass
    def initialize exception_to_throw = nil
      raise exception_to_throw if exception_to_throw
    end
  end
end

def test_exception_in_newing_object args, assert
  begin
    ExceptionalClass.new TypeError
    raise "Exception wasn't thrown!"
  rescue Exception => e
    assert.equal! e.class, TypeError, "Exceptions within constructor should be retained."
  end
end

Unit Tests - fn_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/fn_tests.rb
def infinity
  1 / 0
end

def neg_infinity
  -1 / 0
end

def nan
  0.0 / 0
end

def test_add args, assert
  assert.equal! (args.fn.add), 0
  assert.equal! (args.fn.+), 0
  assert.equal! (args.fn.+ 1, 2, 3), 6
  assert.equal! (args.fn.+ 0), 0
  assert.equal! (args.fn.+ 0, nil), 0
  assert.equal! (args.fn.+ 0, nan), nil
  assert.equal! (args.fn.+ 0, nil, infinity), nil
  assert.equal! (args.fn.+ [1, 2, 3, [4, 5, 6]]), 21
  assert.equal! (args.fn.+ [nil, [4, 5, 6]]), 15
end

def test_sub args, assert
  neg_infinity = infinity * -1
  assert.equal! (args.fn.+), 0
  assert.equal! (args.fn.- 1, 2, 3), -4
  assert.equal! (args.fn.- 4), -4
  assert.equal! (args.fn.- 4, nan), nil
  assert.equal! (args.fn.- 0, nil), 0
  assert.equal! (args.fn.- 0, nil, infinity), nil
  assert.equal! (args.fn.- [0, 1, 2, 3, [4, 5, 6]]), -21
  assert.equal! (args.fn.- [nil, 0, [4, 5, 6]]), -15
end

def test_div args, assert
  assert.equal! (args.fn.div), 1
  assert.equal! (args.fn./), 1
  assert.equal! (args.fn./ 6, 3), 2
  assert.equal! (args.fn./ 6, infinity), nil
  assert.equal! (args.fn./ 6, nan), nil
  assert.equal! (args.fn./ infinity), nil
  assert.equal! (args.fn./ 0), nil
  assert.equal! (args.fn./ 6, [3]), 2
end

def test_idiv args, assert
  assert.equal! (args.fn.idiv), 1
  assert.equal! (args.fn.idiv 7, 3), 2
  assert.equal! (args.fn.idiv 6, infinity), nil
  assert.equal! (args.fn.idiv 6, nan), nil
  assert.equal! (args.fn.idiv infinity), nil
  assert.equal! (args.fn.idiv 0), nil
  assert.equal! (args.fn.idiv 7, [3]), 2
end

def test_mul args, assert
  assert.equal! (args.fn.mul), 1
  assert.equal! (args.fn.*), 1
  assert.equal! (args.fn.* 7, 3), 21
  assert.equal! (args.fn.* 6, nan), nil
  assert.equal! (args.fn.* 6, infinity), nil
  assert.equal! (args.fn.* infinity), nil
  assert.equal! (args.fn.* 0), 0
  assert.equal! (args.fn.* 7, [3]), 21
end

def test_acopy args, assert
  orig  = [1, 2, 3]
  clone = args.fn.acopy orig
  assert.equal! clone, [1, 2, 3]
  assert.equal! clone, orig
  assert.not_equal! clone.object_id, orig.object_id
end

def test_aget args, assert
  assert.equal! (args.fn.aget [:a, :b, :c], 1), :b
  assert.equal! (args.fn.aget [:a, :b, :c], nil), nil
  assert.equal! (args.fn.aget nil, 1), nil
end

def test_alength args, assert
  assert.equal! (args.fn.alength [:a, :b, :c]), 3
  assert.equal! (args.fn.alength nil), nil
end

def test_amap args, assert
  inc = lambda { |i| i + 1 }
  ary = [1, 2, 3]
  assert.equal! (args.fn.amap ary, inc), [2, 3, 4]
  assert.equal! (args.fn.amap nil, inc), nil
  assert.equal! (args.fn.amap ary, nil), nil
  assert.equal! (args.fn.amap ary, inc).class, Array
end

def test_and args, assert
  assert.equal! (args.fn.and 1, 2, 3, 4), 4
  assert.equal! (args.fn.and 1, 2, nil, 4), nil
  assert.equal! (args.fn.and), true
end

def test_or args, assert
  assert.equal! (args.fn.or 1, 2, 3, 4), 1
  assert.equal! (args.fn.or 1, 2, nil, 4), 1
  assert.equal! (args.fn.or), nil
  assert.equal! (args.fn.or nil, nil, false, 5, 10), 5
end

def test_eq_eq args, assert
  assert.equal! (args.fn.eq?), true
  assert.equal! (args.fn.eq? 1, 0), false
  assert.equal! (args.fn.eq? 1, 1, 1), true
  assert.equal! (args.fn.== 1, 1, 1), true
  assert.equal! (args.fn.== nil, nil), true
end

def test_apply args, assert
  assert.equal! (args.fn.and [nil, nil, nil]), [nil, nil, nil]
  assert.equal! (args.fn.apply [nil, nil, nil], args.fn.method(:and)), nil
  and_lambda = lambda {|*xs| args.fn.and(*xs)}
  assert.equal! (args.fn.apply [nil, nil, nil], and_lambda), nil
end

def test_areduce args, assert
  assert.equal! (args.fn.areduce [1, 2, 3], 0, lambda { |i, a| i + a }), 6
end

def test_array_hash args, assert
  assert.equal! (args.fn.array_hash :a, 1, :b, 2), { a: 1, b: 2 }
  assert.equal! (args.fn.array_hash), { }
end

Unit Tests - gen_docs.rb link

# ./samples/10_advanced_debugging/03_unit_tests/gen_docs.rb
# ./dragonruby . --eval samples/10_advanced_debugging/03_unit_tests/gen_docs.rb --no-tick
# OR
# ./dragonruby ./samples/10_advanced_debugging/03_unit_tests --test gen_docs.rb
Kernel.export_docs!

Unit Tests - geometry_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/geometry_tests.rb
begin :shared
  def primitive_representations x, y, w, h
    [
      [x, y, w, h],
      { x: x, y: y, w: w, h: h },
      RectForTest.new(x, y, w, h)
    ]
  end

  class RectForTest
    attr_sprite

    def initialize x, y, w, h
      @x = x
      @y = y
      @w = w
      @h = h
    end

    def to_s
      "RectForTest: #{[x, y, w, h]}"
    end
  end
end

begin :intersect_rect?
  def test_intersect_rect_point args, assert
    assert.true! [16, 13].intersect_rect?([13, 12, 4, 4]), "point intersects with rect."
  end

  def test_intersect_rect args, assert
    intersecting = primitive_representations(0, 0, 100, 100) +
                   primitive_representations(20, 20, 20, 20)

    intersecting.product(intersecting).each do |rect_one, rect_two|
      assert.true! rect_one.intersect_rect?(rect_two),
                   "intersect_rect? assertion failed for #{rect_one}, #{rect_two} (expected true)."
    end

    not_intersecting = [
      [ 0, 0, 5, 5],
      { x: 10, y: 10, w: 5, h: 5 },
      RectForTest.new(20, 20, 5, 5)
    ]

    not_intersecting.product(not_intersecting)
      .reject { |rect_one, rect_two| rect_one == rect_two }
      .each do |rect_one, rect_two|
      assert.false! rect_one.intersect_rect?(rect_two),
                    "intersect_rect? assertion failed for #{rect_one}, #{rect_two} (expected false)."
    end
  end
end

begin :inside_rect?
  def assert_inside_rect outer: nil, inner: nil, expected: nil, assert: nil
    assert.true! inner.inside_rect?(outer) == expected,
                 "inside_rect? assertion failed for outer: #{outer} inner: #{inner} (expected #{expected})."
  end

  def test_inside_rect args, assert
    outer_rects = primitive_representations(0, 0, 10, 10)
    inner_rects = primitive_representations(1, 1, 5, 5)
    primitive_representations(0, 0, 10, 10).product(primitive_representations(1, 1, 5, 5))
      .each do |outer, inner|
      assert_inside_rect outer: outer, inner: inner,
                         expected: true, assert: assert
    end
  end
end

begin :angle_to
  def test_angle_to args, assert
    origins = primitive_representations(0, 0, 0, 0)
    rights = primitive_representations(1, 0, 0, 0)
    aboves = primitive_representations(0, 1, 0, 0)

    origins.product(aboves).each do |origin, above|
      assert.equal! origin.angle_to(above), 90,
                    "A point directly above should be 90 degrees."

      assert.equal! above.angle_from(origin), 90,
                    "A point coming from above should be 90 degrees."
    end

    origins.product(rights).each do |origin, right|
      assert.equal! origin.angle_to(right) % 360, 0,
                    "A point directly to the right should be 0 degrees."

      assert.equal! right.angle_from(origin) % 360, 0,
                    "A point coming from the right should be 0 degrees."

    end
  end
end

begin :scale_rect
  def test_scale_rect args, assert
    assert.equal! [0, 0, 100, 100].scale_rect(0.5, 0.5),
                  [25.0, 25.0, 50.0, 50.0]

    assert.equal! [0, 0, 100, 100].scale_rect(0.5),
                  [0.0, 0.0, 50.0, 50.0]

    assert.equal! [0, 0, 100, 100].scale_rect_extended(percentage_x: 0.5, percentage_y: 0.5, anchor_x: 0.5, anchor_y: 0.5),
                  [25.0, 25.0, 50.0, 50.0]

    assert.equal! [0, 0, 100, 100].scale_rect_extended(percentage_x: 0.5, percentage_y: 0.5, anchor_x: 0, anchor_y: 0),
                  [0.0, 0.0, 50.0, 50.0]
  end
end

Unit Tests - http_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/http_tests.rb
def try_assert_or_schedule args, assert
  if $result[:complete]
    log_info "Request completed! Verifying."
    if $result[:http_response_code] != 200
      log_info "The request yielded a result of #{$result[:http_response_code]} instead of 200."
      exit
    end
    log_info ":try_assert_or_schedule succeeded!"
  else
    args.gtk.schedule_callback Kernel.tick_count + 10 do
      try_assert_or_schedule args, assert
    end
  end
end

def test_http args, assert
  $result = $gtk.http_get 'http://dragonruby.org'
  try_assert_or_schedule args, assert
end

Unit Tests - input_emulation_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/input_emulation_tests.rb
def test_keyboard args, assert
  args.inputs.keyboard.key_down.i = true
  assert.true! args.inputs.keyboard.truthy_keys.include?(:i)
end

Unit Tests - nil_coercion_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/nil_coercion_tests.rb
# numbers
def test_open_entity_add_number args, assert
  assert.nil! args.state.i_value
  args.state.i_value += 5
  assert.equal! args.state.i_value, 5

  assert.nil! args.state.f_value
  args.state.f_value += 5.5
  assert.equal! args.state.f_value, 5.5
end

def test_open_entity_subtract_number args, assert
  assert.nil! args.state.i_value
  args.state.i_value -= 5
  assert.equal! args.state.i_value, -5

  assert.nil! args.state.f_value
  args.state.f_value -= 5.5
  assert.equal! args.state.f_value, -5.5
end

def test_open_entity_multiply_number args, assert
  assert.nil! args.state.i_value
  args.state.i_value *= 5
  assert.equal! args.state.i_value, 0

  assert.nil! args.state.f_value
  args.state.f_value *= 5.5
  assert.equal! args.state.f_value, 0
end

def test_open_entity_divide_number args, assert
  assert.nil! args.state.i_value
  args.state.i_value /= 5
  assert.equal! args.state.i_value, 0

  assert.nil! args.state.f_value
  args.state.f_value /= 5.5
  assert.equal! args.state.f_value, 0
end

# array
def test_open_entity_add_array args, assert
  assert.nil! args.state.values
  args.state.values += [:a, :b, :c]
  assert.equal! args.state.values, [:a, :b, :c]
end

def test_open_entity_subtract_array args, assert
  assert.nil! args.state.values
  args.state.values -= [:a, :b, :c]
  assert.equal! args.state.values, []
end

def test_open_entity_shovel_array args, assert
  assert.nil! args.state.values
  args.state.values << :a
  assert.equal! args.state.values, [:a]
end

def test_open_entity_enumerate args, assert
  assert.nil! args.state.values
  args.state.values = args.state.values.map_with_index { |i| i }
  assert.equal! args.state.values, []

  assert.nil! args.state.values_2
  args.state.values_2 = args.state.values_2.map { |i| i }
  assert.equal! args.state.values_2, []

  assert.nil! args.state.values_3
  args.state.values_3 = args.state.values_3.flat_map { |i| i }
  assert.equal! args.state.values_3, []
end

# hashes
def test_open_entity_indexer args, assert
  GTK::Entity.__reset_id__!
  assert.nil! args.state.values
  args.state.values[:test] = :value
  assert.equal! args.state.values.to_s, { entity_id: 1, entity_name: :values, entity_keys_by_ref: {}, test: :value }.to_s
end

# bug
def test_open_entity_nil_bug args, assert
  GTK::Entity.__reset_id__!
  args.state.foo.a
  args.state.foo.b
  @hello[:foobar]
  assert.nil! args.state.foo.a, "a was not nil."
  # the line below fails
  # assert.nil! args.state.foo.b, "b was not nil."
end

Unit Tests - object_to_primitive_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/object_to_primitive_tests.rb
class PlayerSpriteForTest
end

def test_array_to_sprite args, assert
  array = [[0, 0, 100, 100, "test.png"]].sprites
  puts "No exception was thrown. Sweet!"
end

def test_class_to_sprite args, assert
  array = [PlayerSprite.new].sprites
  assert.true! array.first.is_a?(PlayerSprite)
  puts "No exception was thrown. Sweet!"
end

Unit Tests - parsing_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/parsing_tests.rb
def test_parse_json args, assert
  result = args.gtk.parse_json '{ "name": "John Doe", "aliases": ["JD"] }'
  assert.equal! result, { "name"=>"John Doe", "aliases"=>["JD"] }, "Parsing JSON failed."
end

def test_parse_xml args, assert
  result = args.gtk.parse_xml <<-S
<Person id="100">
  <Name>John Doe</Name>
</Person>
S

 expected = {:type=>:element,
             :name=>nil,
             :children=>[{:type=>:element,
                          :name=>"Person",
                          :children=>[{:type=>:element,
                                       :name=>"Name",
                                       :children=>[{:type=>:content,
                                                    :data=>"John Doe"}]}],
                          :attributes=>{"id"=>"100"}}]}

 assert.equal! result, expected, "Parsing xml failed."
end

Unit Tests - pretty_format_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/pretty_format_tests.rb
def H opts
  opts
end

def A *opts
  opts
end

def assert_format args, assert, hash, expected
  actual = args.fn.pretty_format hash
  assert.are_equal! actual, expected
end

def test_pretty_print args, assert
  # =============================
  # hash with single value
  # =============================
  input = (H first_name: "John")
  expected = <<-S
{:first_name "John"}
S
  (assert_format args, assert, input, expected)

  # =============================
  # hash with two values
  # =============================
  input = (H first_name: "John", last_name: "Smith")
  expected = <<-S
{:first_name "John"
 :last_name "Smith"}
S

  (assert_format args, assert, input, expected)

  # =============================
  # hash with inner hash
  # =============================
  input = (H first_name: "John",
             last_name: "Smith",
             middle_initial: "I",
             so: (H first_name: "Pocahontas",
                    last_name: "Tsenacommacah"),
             friends: (A (H first_name: "Side", last_name: "Kick"),
                         (H first_name: "Tim", last_name: "Wizard")))
  expected = <<-S
{:first_name "John"
 :last_name "Smith"
 :middle_initial "I"
 :so {:first_name "Pocahontas"
      :last_name "Tsenacommacah"}
 :friends [{:first_name "Side"
            :last_name "Kick"}
           {:first_name "Tim"
            :last_name "Wizard"}]}
S

  (assert_format args, assert, input, expected)

  # =============================
  # array with one value
  # =============================
  input = (A 1)
  expected = <<-S
[1]
S
  (assert_format args, assert, input, expected)

  # =============================
  # array with multiple values
  # =============================
  input = (A 1, 2, 3)
  expected = <<-S
[1
 2
 3]
S
  (assert_format args, assert, input, expected)

  # =============================
  # array with multiple values hashes
  # =============================
  input = (A (H first_name: "Side", last_name: "Kick"),
             (H first_name: "Tim", last_name: "Wizard"))
  expected = <<-S
[{:first_name "Side"
  :last_name "Kick"}
 {:first_name "Tim"
  :last_name "Wizard"}]
S

  (assert_format args, assert, input, expected)
end

def test_nested_nested args, assert
  # =============================
  # nested array in nested hash
  # =============================
  input = (H type: :root,
             text: "Root",
             children: (A (H level: 1,
                             text: "Level 1",
                             children: (A (H level: 2,
                                             text: "Level 2",
                                             children: [])))))

  expected = <<-S
{:type :root
 :text "Root"
 :children [{:level 1
             :text "Level 1"
             :children [{:level 2
                         :text "Level 2"
                         :children []}]}]}

S

  (assert_format args, assert, input, expected)
end

def test_scene args, assert
  script = <<-S
* Scene 1
** Narrator
They say happy endings don't exist.
** Narrator
They say true love is a lie.
S
  input = parse_org args, script
  puts (args.fn.pretty_format input)
end

Unit Tests - require_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/require_tests.rb
def write_src path, src
  $gtk.write_file path, src
end

write_src 'app/unit_testing_game.rb', <<-S
module UnitTesting
  class Game
  end
end
S

write_src 'lib/unit_testing_lib.rb', <<-S
module UnitTesting
  class Lib
  end
end
S

write_src 'app/nested/unit_testing_nested.rb', <<-S
module UnitTesting
  class Nested
  end
end
S

require 'app/unit_testing_game.rb'
require 'app/nested/unit_testing_nested.rb'
require 'lib/unit_testing_lib.rb'

def test_require args, assert
  UnitTesting::Game.new
  UnitTesting::Lib.new
  UnitTesting::Nested.new
  $gtk.exec 'rm ./mygame/app/unit_testing_game.rb'
  $gtk.exec 'rm ./mygame/app/nested/unit_testing_nested.rb'
  $gtk.exec 'rm ./mygame/lib/unit_testing_lib.rb'
  assert.ok!
end

Unit Tests - serialize_deserialize_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/serialize_deserialize_tests.rb
def assert_hash_strings! assert, string_1, string_2
  Kernel.eval("$assert_hash_string_1 = #{string_1}")
  Kernel.eval("$assert_hash_string_2 = #{string_2}")
  assert.equal! $assert_hash_string_1, $assert_hash_string_2
end


def test_serialize args, assert
  args.state.player_one = "test"
  result = args.gtk.serialize_state args.state
  assert_hash_strings! assert, result, "{:entity_id=>1, :entity_keys_by_ref=>{}, :tick_count=>-1, :player_one=>\"test\"}"

  args.gtk.write_file 'state.txt', ''
  result = args.gtk.serialize_state 'state.txt', args.state
  assert_hash_strings! assert, result, "{:entity_id=>1, :entity_keys_by_ref=>{}, :tick_count=>-1, :player_one=>\"test\"}"
end

def test_deserialize args, assert
  result = args.gtk.deserialize_state '{:entity_id=>3, :tick_count=>-1, :player_one=>"test"}'
  assert.equal! result.player_one, "test"

  args.gtk.write_file 'state.txt',  '{:entity_id=>3, :tick_count=>-1, :player_one=>"test"}'
  result = args.gtk.deserialize_state 'state.txt'
  assert.equal! result.player_one, "test"
end

def test_very_large_serialization args, assert
  args.gtk.write_file("logs/log.txt", "")
  size = 3000
  size.map_with_index do |i|
    args.state.send("k#{i}=".to_sym, i)
  end

  result = args.gtk.serialize_state args.state
  assert.true! $serialize_state_serialization_too_large
end

def test_strict_entity_serialization args, assert
  args.state.player_one = args.state.new_entity(:player, name: "Ryu")
  args.state.player_two = args.state.new_entity_strict(:player_strict, name: "Ken")

  serialized_state = args.gtk.serialize_state args.state
  assert_hash_strings! assert, serialized_state, '{:entity_id=>1, :entity_keys_by_ref=>{}, :tick_count=>-1, :player_one=>{:entity_id=>3, :entity_name=>:player, :entity_keys_by_ref=>{}, :entity_type=>:player, :created_at=>-1, :global_created_at=>-1, :name=>"Ryu"}, :player_two=>{:entity_id=>5, :entity_name=>:player_strict, :entity_type=>:player_strict, :created_at=>-1, :global_created_at_elapsed=>-1, :entity_strict=>true, :entity_keys_by_ref=>{}, :name=>"Ken"}}'

  deserialize_state = args.gtk.deserialize_state serialized_state

  assert.equal! args.state.player_one.name, deserialize_state.player_one.name
  assert.true! args.state.player_one.is_a? GTK::OpenEntity

  assert.equal! args.state.player_two.name, deserialize_state.player_two.name
  assert.true! args.state.player_two.is_a? GTK::StrictEntity
end

def test_strict_entity_serialization_with_nil args, assert
  args.state.player_one = args.state.new_entity(:player, name: "Ryu")
  args.state.player_two = args.state.new_entity_strict(:player_strict, name: "Ken", blood_type: nil)

  serialized_state = args.gtk.serialize_state args.state
  assert_hash_strings! assert, serialized_state, '{:entity_id=>1, :entity_keys_by_ref=>{}, :tick_count=>-1, :player_one=>{:entity_id=>3, :entity_name=>:player, :entity_keys_by_ref=>{}, :entity_type=>:player, :created_at=>-1, :global_created_at=>-1, :name=>"Ryu"}, :player_two=>{:entity_name=>:player_strict, :global_created_at_elapsed=>-1, :created_at=>-1, :blood_type=>nil, :name=>"Ken", :entity_type=>:player_strict, :entity_strict=>true, :entity_keys_by_ref=>{}, :entity_id=>4}}'

  deserialized_state = args.gtk.deserialize_state serialized_state

  assert.equal! args.state.player_one.name, deserialized_state.player_one.name
  assert.true! args.state.player_one.is_a? GTK::OpenEntity

  assert.equal! args.state.player_two.name, deserialized_state.player_two.name
  assert.equal! args.state.player_two.blood_type, deserialized_state.player_two.blood_type
  assert.equal! deserialized_state.player_two.blood_type, nil
  assert.true! args.state.player_two.is_a? GTK::StrictEntity

  deserialized_state.player_two.blood_type = :O
  assert.equal! deserialized_state.player_two.blood_type, :O
end

def test_multiple_strict_entities args, assert
  args.state.player = args.state.new_entity_strict(:player_one, name: "Ryu")
  args.state.enemy = args.state.new_entity_strict(:enemy, name: "Bison", other_property: 'extra mean')

  serialized_state = args.gtk.serialize_state args.state

  deserialized_state = args.gtk.deserialize_state serialized_state

  assert.equal! deserialized_state.player.name, "Ryu"
  assert.equal! deserialized_state.enemy.other_property, "extra mean"
end

def test_by_reference_state args, assert
  args.state.a = args.state.new_entity(:person, name: "Jane Doe")
  args.state.b = args.state.a
  assert.equal! args.state.a.object_id, args.state.b.object_id
  serialized_state = args.gtk.serialize_state args.state

  deserialized_state = args.gtk.deserialize_state serialized_state
  assert.equal! deserialized_state.a.object_id, deserialized_state.b.object_id
end

def test_by_reference_state_strict_entities args, assert
  args.state.strict_entity = args.state.new_entity_strict(:couple) do |e|
    e.one = args.state.new_entity_strict(:person, name: "Jane")
    e.two = e.one
  end
  assert.equal! args.state.strict_entity.one, args.state.strict_entity.two
  serialized_state = args.gtk.serialize_state args.state

  deserialized_state = args.gtk.deserialize_state serialized_state
  assert.equal! deserialized_state.strict_entity.one, deserialized_state.strict_entity.two
end

def test_serialization_excludes_thrash_count args, assert
  args.state.player.name = "Ryu"
  # force a nil pun
  if args.state.player.age > 30
  end
  assert.equal! args.state.player.as_hash[:__thrash_count__][:>], 1
  result = args.gtk.serialize_state args.state
  assert.false! (result.include? "__thrash_count__"),
                "The __thrash_count__ key exists in state when it shouldn't have."
end

def test_serialization_does_not_mix_up_zero_and_true args, assert
  args.state.enemy.evil = true
  args.state.enemy.hp = 0
  serialized = args.gtk.serialize_state args.state.enemy

  deserialized = args.gtk.deserialize_state serialized

  assert.equal! deserialized.hp, 0,
                "Value should have been deserialized as 0, but was #{deserialized.hp}"
  assert.equal! deserialized.evil, true,
                "Value should have been deserialized as true, but was #{deserialized.evil}"
end

Unit Tests - state_serialization_experimental_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/state_serialization_experimental_tests.rb
MAX_CODE_GEN_LENGTH = 50

# NOTE: This is experimental/advanced stuff.
def needs_partitioning? target
  target[:value].to_s.length > MAX_CODE_GEN_LENGTH
end

def partition target
  return [] unless needs_partitioning? target
  if target[:value].is_a? GTK::OpenEntity
    target[:value] = target[:value].hash
  end

  results = []
  idx = 0
  left, right = target[:value].partition do
    idx += 1
    idx.even?
  end
  left, right = Hash[left], Hash[right]
  left = { value: left }
  right = { value: right}
  [left, right]
end

def add_partition target, path, aggregate, final_result
  partitions = partition target
  partitions.each do |part|
    if needs_partitioning? part
      if part[:value].keys.length == 1
        first_key = part[:value].keys[0]
        new_part = { value: part[:value][first_key] }
        path.push first_key
        add_partition new_part, path, aggregate, final_result
        path.pop
      else
        add_partition part, path, aggregate, final_result
      end
    else
      final_result << { value: { __path__: [*path] } }
      final_result << { value: part[:value] }
    end
  end
end

def state_to_string state
  parts_queue = []
  final_queue = []
  add_partition({ value: state.hash },
                [],
                parts_queue,
                final_queue)
  final_queue.reject {|i| i[:value].keys.length == 0}.map do |i|
    i[:value].to_s
  end.join("\n#==================================================#\n")
end

def state_from_string string
  Kernel.eval("$load_data = {}")
  lines = string.split("\n#==================================================#\n")
  lines.each do |l|
    puts "todo: #{l}"
  end

  GTK::OpenEntity.parse_from_hash $load_data
end

def test_save_and_load args, assert
  args.state.item_1.name = "Jane"
  string = state_to_string args.state
  state = state_from_string string
  assert.equal! args.state.item_1.name, state.item_1.name
end

def test_save_and_load_big args, assert
  size = 1000
  size.map_with_index do |i|
    args.state.send("k#{i}=".to_sym, i)
  end

  string = state_to_string args.state
  state = state_from_string string
  size.map_with_index do |i|
    assert.equal! args.state.send("k#{i}".to_sym), state.send("k#{i}".to_sym)
    assert.equal! args.state.send("k#{i}".to_sym), i
    assert.equal! state.send("k#{i}".to_sym), i
  end
end

def test_save_and_load_big_nested args, assert
  args.state.player_one.friend.nested_hash.k0 = 0
  args.state.player_one.friend.nested_hash.k1 = 1
  args.state.player_one.friend.nested_hash.k2 = 2
  args.state.player_one.friend.nested_hash.k3 = 3
  args.state.player_one.friend.nested_hash.k4 = 4
  args.state.player_one.friend.nested_hash.k5 = 5
  args.state.player_one.friend.nested_hash.k6 = 6
  args.state.player_one.friend.nested_hash.k7 = 7
  args.state.player_one.friend.nested_hash.k8 = 8
  args.state.player_one.friend.nested_hash.k9 = 9
  string = state_to_string args.state
  state = state_from_string string
end

Unit Tests - suggest_autocompletion_tests.rb link

# ./samples/10_advanced_debugging/03_unit_tests/suggest_autocompletion_tests.rb
def default_suggest_autocompletion args
  {
    index: 4,
    text: "args.",
    __meta__: {
      other_options: [
        {
          index: Fixnum,
          file: "app/main.rb"
        }
      ]
    }
  }
end

def assert_completion source, *expected
  results = suggest_autocompletion text:  (source.strip.gsub  ":cursor", ""),
                                   index: (source.strip.index ":cursor")

  puts results
end

def test_args_completion args, assert
  $gtk.write_file_root "autocomplete.txt", ($gtk.suggest_autocompletion text: <<-S, index: 128).join("\n")
require 'app/game.rb'

def tick args
  args.gtk.suppress_mailbox = false
  $game ||= Game.new
  $game.args = args
  $game.args.
  $game.tick
end
S

  puts "contents:"
  puts ($gtk.read_file "autocomplete.txt")
end

Http link

Retrieve Images - main.rb link

# ./samples/11_http/01_retrieve_images/app/main.rb
$gtk.register_cvar 'app.warn_seconds', "seconds to wait before starting", :uint, 11

def tick args
  args.outputs.background_color = [0, 0, 0]

  # Show a warning at the start.
  args.state.warning_debounce ||= args.cvars['app.warn_seconds'].value * 60
  if args.state.warning_debounce > 0
    args.state.warning_debounce -= 1
    args.outputs.labels << [640, 600, "This app shows random images from the Internet.", 10, 1, 255, 255, 255]
    args.outputs.labels << [640, 500, "Quit in the next few seconds if this is a problem.", 10, 1, 255, 255, 255]
    args.outputs.labels << [640, 350, "#{(args.state.warning_debounce / 60.0).to_i}", 10, 1, 255, 255, 255]
    return
  end

  args.state.download_debounce ||= 0   # start immediately, reset to non zero later.
  args.state.photos ||= []

  # Put a little pause between each download.
  if args.state.download.nil?
    if args.state.download_debounce > 0
      args.state.download_debounce -= 1
    else
      args.state.download = $gtk.http_get 'https://picsum.photos/200/300.jpg'
    end
  end

  if !args.state.download.nil?
    if args.state.download[:complete]
      if args.state.download[:http_response_code] == 200
        fname = "sprites/#{args.state.photos.length}.jpg"
        $gtk.write_file fname, args.state.download[:response_data]
        args.state.photos << [ 100 + rand(1080), 500 - rand(480), fname, rand(80) - 40 ]
      end
      args.state.download = nil
      args.state.download_debounce = (rand(3) + 2) * 60
    end
  end

  # draw any downloaded photos...
  args.state.photos.each { |i|
    args.outputs.primitives << [i[0], i[1], 200, 300, i[2], i[3]].sprite
  }

  # Draw a download progress bar...
  args.outputs.primitives << [0, 0, 1280, 30, 0, 0, 0, 255].solid
  if !args.state.download.nil?
    br = args.state.download[:response_read]
    total = args.state.download[:response_total]
    if total != 0
      pct = br.to_f / total.to_f
      args.outputs.primitives << [0, 0, 1280 * pct, 30, 0, 0, 255, 255].solid
    end
  end
end

In Game Web Server Http Get - main.rb link

# ./samples/11_http/02_in_game_web_server_http_get/app/main.rb
def tick args
  args.state.reqnum ||= 0
  # by default the embedded webserver is disabled in a production build
  # to enable the http server in a production build you need to:
  # - update metadata/cvars.txt
  # - manually start the server up with enable_in_prod set to true:
  args.gtk.start_server! port: 3000, enable_in_prod: true
  args.outputs.background_color = [0, 0, 0]
  args.outputs.labels << { x: 640,
                           y: 360,
                           text: "Point your web browser at http://localhost:#{args.state.port}/",
                           size_px: 30,
                           anchor_x: 0.5,
                           anchor_y: 0.5 }

  args.outputs.labels << { x: 640,
                           y: 360,
                           text: "See metadata/cvars.txt for webserer configuration requirements.",
                           size_px: 30,
                           anchor_x: 0.5,
                           anchor_y: 1.5 }

  if Kernel.tick_count == 1
    $gtk.openurl "http://localhost:3000"
  end

  args.inputs.http_requests.each { |req|
    puts("METHOD: #{req.method}");
    puts("URI: #{req.uri}");
    puts("HEADERS:");
    req.headers.each { |k,v| puts("  #{k}: #{v}") }

    if (req.uri == '/')
      # headers and body can be nil if you don't care about them.
      # If you don't set the Content-Type, it will default to
      #  "text/html; charset=utf-8".
      # Don't set Content-Length; we'll ignore it and calculate it for you
      args.state.reqnum += 1
      req.respond 200, "<html><head><title>hello</title></head><body><h1>This #{req.method} was request number #{args.state.reqnum}!</h1></body></html>\n", { 'X-DRGTK-header' => 'Powered by DragonRuby!' }
    else
      req.reject
    end
  }
end

In Game Web Server Http Get - Metadata - cvars.txt link

# ./samples/11_http/02_in_game_web_server_http_get/metadata/cvars.txt
webserver.enabled=true
webserver.port=3000
webserver.remote_clients=false

In Game Web Server Http Post - main.rb link

# ./samples/11_http/03_in_game_web_server_http_post/app/main.rb
def tick args
  # by default the embedded webserver is disabled in a production build
  # to enable the http server in a production build you need to:
  # - update metadata/cvars.txt
  # - manually start the server up with enable_in_prod set to true:
  args.gtk.start_server! port: $cvars["webserver.port"].value, enable_in_prod: true

  # defaults
  args.state.post_button      = args.layout.rect(row: 0, col: 0, w: 5, h: 1).merge(text: "execute http_post")
  args.state.post_body_button = args.layout.rect(row: 1, col: 0, w: 5, h: 1).merge(text: "execute http_post_body")
  args.state.request_to_s ||= ""
  args.state.request_body ||= ""

  # render
  args.state.post_button.yield_self do |b|
    args.outputs.borders << b
    args.outputs.labels  << b.merge(text: b.text,
                                    y:    b.y + 30,
                                    x:    b.x + 10)
  end

  args.state.post_body_button.yield_self do |b|
    args.outputs.borders << b
    args.outputs.labels  << b.merge(text: b.text,
                                    y:    b.y + 30,
                                    x:    b.x + 10)
  end

  draw_label args, 0,  6, "Request:", args.state.request_to_s
  draw_label args, 0, 14, "Request Body Unaltered:", args.state.request_body

  # input
  if args.inputs.mouse.click
    # ============= HTTP_POST =============
    if (args.inputs.mouse.inside_rect? args.state.post_button)
      # ========= DATA TO SEND ===========
      form_fields = { "userId" => "#{Time.now.to_i}" }
      # ==================================

      args.gtk.http_post "http://localhost:9001/testing",
                         form_fields,
                         ["Content-Type: application/x-www-form-urlencoded"]

      args.gtk.notify! "http_post"
    end

    # ============= HTTP_POST_BODY =============
    if (args.inputs.mouse.inside_rect? args.state.post_body_button)
      # =========== DATA TO SEND ==============
      json = "{ \"userId\": \"#{Time.now.to_i}\"}"
      # ==================================

      args.gtk.http_post_body "http://localhost:9001/testing",
                              json,
                              ["Content-Type: application/json", "Content-Length: #{json.length}"]

      args.gtk.notify! "http_post_body"
    end
  end

  # calc
  args.inputs.http_requests.each do |r|
    puts "#{r}"
    if r.uri == "/testing"
      puts r
      args.state.request_to_s = "#{r}"
      args.state.request_body = r.raw_body
      r.respond 200, "ok"
    end
  end
end

def draw_label args, row, col, header, text
  label_pos = args.layout.rect(row: row, col: col, w: 0, h: 0)
  args.outputs.labels << "#{header}\n\n#{text}".wrapped_lines(80).map_with_index do |l, i|
    { x: label_pos.x, y: label_pos.y - (i * 15), text: l, size_enum: -2 }
  end
end

In Game Web Server Http Post - Metadata - cvars.txt link

# ./samples/11_http/03_in_game_web_server_http_post/metadata/cvars.txt
webserver.enabled=true
webserver.port=9001
webserver.remote_clients=false

C Extensions link

Basics - main.rb link

# ./samples/12_c_extensions/01_basics/app/main.rb
$gtk.ffi_misc.gtk_dlopen("ext")
include FFI::CExt

def tick args
  args.outputs.labels  << [640, 500, "mouse.x = #{args.mouse.x.to_i}", 5, 1]
  args.outputs.labels  << [640, 460, "square(mouse.x) = #{square(args.mouse.x.to_i)}", 5, 1]
  args.outputs.labels  << [640, 420, "mouse.y = #{args.mouse.y.to_i}", 5, 1]
  args.outputs.labels  << [640, 380, "square(mouse.y) = #{square(args.mouse.y.to_i)}", 5, 1]
end

Intermediate - main.rb link

# ./samples/12_c_extensions/02_intermediate/app/main.rb
$gtk.ffi_misc.gtk_dlopen("ext")
include FFI::RE

def split_words(input)
  words = []
  last = IntPointer.new
  re = re_compile("\\w+")
  first = re_matchp(re, input, last)
  while first != -1
    words << input.slice(first, last.value)
    input = input.slice(last.value + first, input.length)
    first = re_matchp(re, input, last)
  end
  words
end

def tick args
  args.outputs.labels  << [640, 500, split_words("hello, dragonriders!").join(' '), 5, 1]
end

Native Pixel Arrays - main.rb link

# ./samples/12_c_extensions/03_native_pixel_arrays/app/main.rb
$gtk.ffi_misc.gtk_dlopen("ext")
include FFI::CExt

def tick args
  args.state.rotation ||= 0

  update_scanner_texture   # this calls into a C extension!

  # New/changed pixel arrays get uploaded to the GPU before we render
  #  anything. At that point, they can be scaled, rotated, and otherwise
  #  used like any other sprite.
  w = 100
  h = 100
  x = (1280 - w) / 2
  y = (720 - h) / 2
  args.outputs.background_color = [64, 0, 128]
  args.outputs.primitives << [x, y, w, h, :scanner, args.state.rotation].sprite
  args.state.rotation += 1

  args.outputs.primitives << args.gtk.current_framerate_primitives
end

Handcrafted Extension - main.rb link

# ./samples/12_c_extensions/04_handcrafted_extension/app/main.rb
$gtk.ffi_misc.gtk_dlopen("ext")
include FFI::CExt

puts Adder.new.add_all(1, 2, 3, [4, 5, 6.0])

def tick args
end

Handcrafted Extension - license.txt link

# ./samples/12_c_extensions/04_handcrafted_extension/license.txt
Copyright 2022 DragonRuby LLC

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Handcrafted Extension Advanced - main.rb link

# ./samples/12_c_extensions/04_handcrafted_extension_advanced/app/main.rb
def build_c_extension
  v = Time.now.to_i
  $gtk.exec("cd ./mygame && (env SUFFIX=#{v} sh ./pre.sh 2>&1 | tee ./build-results.txt)")
  build_output = $gtk.read_file("build-results.txt")
  {
    dll_name: "ext_#{v}",
    build_output: build_output
  }
end

def tick args
  # sets console command when sample app initially opens
  if Kernel.global_tick_count == 0
    results = build_c_extension
    dll = results.dll_name
    $gtk.dlopen(dll)
    puts ""
    puts ""
    puts "========================================================="
    puts "* INFO: Static Sprites, Classes, Draw Override"
    puts "* INFO: Please specify the number of sprites to render."
    args.gtk.console.set_command "reset_with count: 100"
  end

  args.state.star_count ||= 0

  # init
  if Kernel.tick_count == 0
    args.state.stars = args.state.star_count.map { |i| Star.new }
    args.outputs.static_sprites << args.state.stars
  end

  # render framerate
  args.outputs.background_color = [0, 0, 0]
  args.outputs.primitives << args.gtk.current_framerate_primitives
end

# resets game, and assigns star count given by user
def reset_with count: count
  $gtk.reset
  $gtk.args.state.star_count = count
end

$gtk.reset

Handcrafted Extension Advanced - license.txt link

# ./samples/12_c_extensions/04_handcrafted_extension_advanced/license.txt
Copyright 2022 DragonRuby LLC

MIT License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Handcrafted Extension Advanced - Metadata - cvars.txt link

# ./samples/12_c_extensions/04_handcrafted_extension_advanced/metadata/cvars.txt
log.filter_subsystems=HTTPServer

# Whether or not the game should use the whole display, be sure to
# expose $gtk.set_window_fullscreen(false) or $gtk.request_quit
# to the player so they can get out of full screen mode.
# renderer.fullscreen=true

# Milliseconds to sleep per frame when in the background (zero to disable)
# renderer.background_sleep=0

# Set the window as borderless.
# Note: the ability to quit the application via OS shortcuts will not
# work if this value is true and you must provide a means to exit the
# game and wire it up to $gtk.request_quit
# renderer.borderless=true

Ios main.rb link

# ./samples/12_c_extensions/05_ios_c_extensions/app/main.rb
# NOTE: This is assumed to be executed with mygame as the root directory
#       you'll need to copy this code over there to try it out.

# Steps:
# 1. Create ext.h and ext.m
# 2. Create Info.plist file
# 3. Add before_create_payload to IOSWizard (which does the following):
#    a. run ./dragonruby-bind against C Extension and update implementation file
#    b. create output location for iOS Framework
#    c. compile C extension into Framework
#    d. copy framework to Payload directory and Sign
# 4. Run $wizards.ios.start env: (:prod|:dev|:hotload) to create ipa
# 5. Invoke args.gtk.dlopen giving the name of the C Extensions (~1s to load).
# 6. Invoke methods as needed.

# ===================================================
# before_create_payload iOS Wizard
# ===================================================
class IOSWizard < Wizard
  def before_create_payload
    puts "* INFO - before_create_payload"

    # invoke ./dragonruby-bind
    sh "./dragonruby-bind --output=mygame/ext-bind.m mygame/ext.h"

    # update generated implementation file
    contents = $gtk.read_file "ext-bind.m"
    contents = contents.gsub("#include \"mygame/ext.h\"", "#include \"mygame/ext.h\"\n#include \"mygame/ext.m\"")
    puts contents

    $gtk.write_file "ext-bind.m", contents

    # create output location
    sh "rm -rf ./mygame/native/ios-device/ext.framework"
    sh "mkdir -p ./mygame/native/ios-device/ext.framework"

    # compile C extension into framework
    sh <<-S
clang -I. -I./mruby/include -I./include -o "./mygame/native/ios-device/ext.framework/ext" \\
      -arch arm64 -dynamiclib -isysroot "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk" \\
      -install_name @rpath/ext.framework/ext \\
      -fembed-bitcode -Xlinker -rpath -Xlinker @loader_path/Frameworks -dead_strip -Xlinker -rpath -fobjc-arc -fobjc-link-runtime \\
      -F/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/System/Library/Frameworks \\
      -miphoneos-version-min=10.3 -Wl,-no_pie -licucore -stdlib=libc++ \\
      -framework CFNetwork -framework UIKit -framework Foundation \\
      ./mygame/ext-bind.m
S

    # stage extension
    sh "cp ./mygame/native/ios-device/Info.plist ./mygame/native/ios-device/ext.framework/Info.plist"
    sh "mkdir -p \"#{app_path}/Frameworks/ext.framework/\""
    sh "cp -r \"#{root_folder}/native/ios-device/ext.framework/\" \"#{app_path}/Frameworks/ext.framework/\""

    # sign
    sh <<-S
CODESIGN_ALLOCATE=#{codesign_allocate_path} #{codesign_path} \\
                                            -f -s \"#{certificate_name}\" \\
                                            \"#{app_path}/Frameworks/ext.framework/ext\"
S
  end
end

def tick args
  if Kernel.tick_count == 60 && args.gtk.platform?(:ios)
    args.gtk.dlopen 'ext'
    include FFI::CExt
    puts "the results of hello world are:"
    puts hello_world()
    $gtk.console.show
  end
end

Ios Metadata - cvars.txt link

# ./samples/12_c_extensions/05_ios_c_extensions/metadata/cvars.txt

Ios Metadata - ios_metadata.txt link

# ./samples/12_c_extensions/05_ios_c_extensions/metadata/ios_metadata.txt
teamid=TEAMID
appid=APPID
appname=ICON NAME
version=1.0
devcert=NAME OF DEV CERT
prodcert=NAME OF PROD CERT

Handcrafted Mac Extension - main.rb link

# ./samples/12_c_extensions/06_handcrafted_mac_extension/app/main.rb
def boot args
  $gtk.dlopen 'ext'
end

def tick args
  if Kernel.tick_count == 0
    hello = Hello.new
    puts hello.get_message("John Doe")
    bye = Bye.new
    puts bye.get_message("John Doe")
  end
end

Handcrafted Mac Extension - readme.txt link

# ./samples/12_c_extensions/06_handcrafted_mac_extension/readme.txt
Build script for C Extension is located under ./mygame/app-native/build.sh.

The build script assumes that the sample code has been copied over to the root mygame directory.

Handcrafted Steam Extensions-native - Steam - download.txt link

# ./samples/12_c_extensions/07_handcrafted_steam_extensions/app-native/steam/download.txt
Download Steamworks SDK, unzip, and place contents of "sdk" folder here: https://partner.steamgames.com/downloads/list

Handcrafted Steam Extensions-native - steam_appid.txt link

# ./samples/12_c_extensions/07_handcrafted_steam_extensions/app-native/steam_appid.txt
2425950

Handcrafted Steam Extensions - main.rb link

# ./samples/12_c_extensions/07_handcrafted_steam_extensions/app/main.rb
def boot args
  $gtk.dlopen 'ext'
  $steam = Steam.new
  $steam.init_api
end

def tick args
  if Kernel.tick_count == 0
    puts "Retrieving user name."
    puts $steam.get_user_name
  end
end

Handcrafted Steam Extensions - readme.txt link

# ./samples/12_c_extensions/07_handcrafted_steam_extensions/readme.txt
Build script for C Extension is located under ./mygame/app-native/build.sh.

The build script assumes that the sample code has been copied over to the root mygame directory.

Path Finding Algorithms link

Breadth First Search - main.rb link

# ./samples/13_path_finding_algorithms/01_breadth_first_search/app/main.rb
# Contributors outside of DragonRuby who also hold Copyright:
# - Sujay Vadlakonda: https://github.com/sujayvadlakonda

# A visual demonstration of a breadth first search
# Inspired by https://www.redblobgames.com/pathfinding/a-star/introduction.html

# An animation that can respond to user input in real time

# A breadth first search expands in all directions one step at a time
# The frontier is a queue of cells to be expanded from
# The visited hash allows quick lookups of cells that have been expanded from
# The walls hash allows quick lookup of whether a cell is a wall

# The breadth first search starts by adding the red star to the frontier array
# and marking it as visited
# Each step a cell is removed from the front of the frontier array (queue)
# Unless the neighbor is a wall or visited, it is added to the frontier array
# The neighbor is then marked as visited

# The frontier is blue
# Visited cells are light brown
# Walls are camo green
# Even when walls are visited, they will maintain their wall color

# The star can be moved by clicking and dragging
# Walls can be added and removed by clicking and dragging

class BreadthFirstSearch
  attr_gtk

  def initialize(args)
    # Variables to edit the size and appearance of the grid
    # Freely customizable to user's liking
    args.state.grid.width     = 30
    args.state.grid.height    = 15
    args.state.grid.cell_size = 40

    # Stores which step of the animation is being rendered
    # When the user moves the star or messes with the walls,
    # the breadth first search is recalculated up to this step
    args.state.anim_steps = 0

    # At some step the animation will end,
    # and further steps won't change anything (the whole grid will be explored)
    # This step is roughly the grid's width * height
    # When anim_steps equals max_steps no more calculations will occur
    # and the slider will be at the end
    args.state.max_steps  = args.state.grid.width * args.state.grid.height

    # Whether the animation should play or not
    # If true, every tick moves anim_steps forward one
    # Pressing the stepwise animation buttons will pause the animation
    args.state.play       = true

    # The location of the star and walls of the grid
    # They can be modified to have a different initial grid
    # Walls are stored in a hash for quick look up when doing the search
    args.state.star       = [0, 0]
    args.state.walls      = {
      [3, 3] => true,
      [3, 4] => true,
      [3, 5] => true,
      [3, 6] => true,
      [3, 7] => true,
      [3, 8] => true,
      [3, 9] => true,
      [3, 10] => true,
      [3, 11] => true,
      [4, 3] => true,
      [4, 4] => true,
      [4, 5] => true,
      [4, 6] => true,
      [4, 7] => true,
      [4, 8] => true,
      [4, 9] => true,
      [4, 10] => true,
      [4, 11] => true,

      [13, 0] => true,
      [13, 1] => true,
      [13, 2] => true,
      [13, 3] => true,
      [13, 4] => true,
      [13, 5] => true,
      [13, 6] => true,
      [13, 7] => true,
      [13, 8] => true,
      [13, 9] => true,
      [13, 10] => true,
      [14, 0] => true,
      [14, 1] => true,
      [14, 2] => true,
      [14, 3] => true,
      [14, 4] => true,
      [14, 5] => true,
      [14, 6] => true,
      [14, 7] => true,
      [14, 8] => true,
      [14, 9] => true,
      [14, 10] => true,

      [21, 8] => true,
      [21, 9] => true,
      [21, 10] => true,
      [21, 11] => true,
      [21, 12] => true,
      [21, 13] => true,
      [21, 14] => true,
      [22, 8] => true,
      [22, 9] => true,
      [22, 10] => true,
      [22, 11] => true,
      [22, 12] => true,
      [22, 13] => true,
      [22, 14] => true,
      [23, 8] => true,
      [23, 9] => true,
      [24, 8] => true,
      [24, 9] => true,
      [25, 8] => true,
      [25, 9] => true,
    }

    # Variables that are used by the breadth first search
    # Storing cells that the search has visited, prevents unnecessary steps
    # Expanding the frontier of the search in order makes the search expand
    # from the center outward
    args.state.visited    = {}
    args.state.frontier   = []


    # What the user is currently editing on the grid
    # Possible values are: :none, :slider, :star, :remove_wall, :add_wall

    # We store this value, because we want to remember the value even when
    # the user's cursor is no longer over what they're interacting with, but
    # they are still clicking down on the mouse.
    args.state.click_and_drag = :none

    # Store the rects of the buttons that control the animation
    # They are here for user customization
    # Editing these might require recentering the text inside them
    # Those values can be found in the render_button methods

    args.state.buttons.left   = { x: 450, y: 600, w: 50,  h: 50 }
    args.state.buttons.center = { x: 500, y: 600, w: 200, h: 50 }
    args.state.buttons.right  = { x: 700, y: 600, w: 50,  h: 50 }

    # The variables below are related to the slider
    # They allow the user to customize them
    # They also give a central location for the render and input methods to get
    # information from
    # x & y are the coordinates of the leftmost part of the slider line
    args.state.slider.x = 400
    args.state.slider.y = 675
    # This is the width of the line
    args.state.slider.w = 360
    # This is the offset for the circle
    # Allows the center of the circle to be on the line,
    # as opposed to the upper right corner
    args.state.slider.offset = 20
    # This is the spacing between each of the notches on the slider
    # Notches are places where the circle can rest on the slider line
    # There needs to be a notch for each step before the maximum number of steps
    args.state.slider.spacing = args.state.slider.w.to_f / args.state.max_steps.to_f
  end

  # This method is called every frame/tick
  # Every tick, the current state of the search is rendered on the screen,
  # User input is processed, and
  # The next step in the search is calculated
  def tick
    render
    input
    # If animation is playing, and max steps have not been reached
    # Move the search a step forward
    if state.play && state.anim_steps < state.max_steps
      # Variable that tells the program what step to recalculate up to
      state.anim_steps += 1
      calc
    end
  end

  # Draws everything onto the screen
  def render
    render_buttons
    render_slider

    render_background
    render_visited
    render_frontier
    render_walls
    render_star
  end

  # The methods below subdivide the task of drawing everything to the screen

  # Draws the buttons that control the animation step and state
  def render_buttons
    render_left_button
    render_center_button
    render_right_button
  end

  # Draws the button which steps the search backward
  # Shows the user where to click to move the search backward
  def render_left_button
    # Draws the gray button, and a black border
    # The border separates the buttons visually
    outputs.solids  << buttons.left.merge(gray)
    outputs.borders << buttons.left

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    # If the button size is changed, the label might need to be edited as well
    # to keep the label in the center of the button
    label_x = buttons.left[:x] + 20
    label_y = buttons.left[:y] + 35
    outputs.labels << { x: label_x, y: label_y, text: '<' }
  end

  def render_center_button
    # Draws the gray button, and a black border
    # The border separates the buttons visually
    outputs.solids  << buttons.center.merge(gray)
    outputs.borders << buttons.center

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    # If the button size is changed, the label might need to be edited as well
    # to keep the label in the center of the button
    label_x = buttons.center[:x] + 37
    label_y = buttons.center[:y] + 35
    label_text = state.play ? "Pause Animation" : "Play Animation"
    outputs.labels << { x: label_x, y: label_y, text: label_text }
  end

  def render_right_button
    # Draws the gray button, and a black border
    # The border separates the buttons visually
    outputs.solids  << buttons.right.merge(gray)
    outputs.borders << buttons.right

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    label_x = buttons.right[:x] + 20
    label_y = buttons.right[:y] + 35
    outputs.labels << { x: label_x, y: label_y, text: ">" }
  end

  # Draws the slider so the user can move it and see the progress of the search
  def render_slider
    # Using a solid instead of a line, hides the line under the circle of the slider
    # Draws the line
    outputs.solids << {
      x: slider.x,
      y: slider.y,
      w: slider.w,
      h: 2
    }
    # The circle needs to be offset so that the center of the circle
    # overlaps the line instead of the upper right corner of the circle
    # The circle's x value is also moved based on the current seach step
    circle_x = (slider.x - slider.offset) + (state.anim_steps * slider.spacing)
    circle_y = (slider.y - slider.offset)
    outputs.sprites << {
      x: circle_x,
      y: circle_y,
      w: 37,
      h: 37,
      path: 'circle-white.png'
    }
  end

  # Draws what the grid looks like with nothing on it
  def render_background
    render_unvisited
    render_grid_lines
  end

  # Draws a rectangle the size of the entire grid to represent unvisited cells
  def render_unvisited
    rect = { x: 0, y: 0, w: grid.width, h: grid.height }
    rect = rect.transform_values { |v| v * grid.cell_size }
    outputs.solids << rect.merge(unvisited_color)
  end

  # Draws grid lines to show the division of the grid into cells
  def render_grid_lines
    outputs.lines << (0..grid.width).map { |x| vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| horizontal_line(y) }
  end

  # Easy way to draw vertical lines given an index
  def vertical_line x
    line = { x: x, y: 0, w: 0, h: grid.height }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Easy way to draw horizontal lines given an index
  def horizontal_line y
    line = { x: 0, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Draws the area that is going to be searched from
  # The frontier is the most outward parts of the search
  def render_frontier
    outputs.solids << state.frontier.map do |cell|
      render_cell cell, frontier_color
    end
  end

  # Draws the walls
  def render_walls
    outputs.solids << state.walls.map do |wall|
      render_cell wall, wall_color
    end
  end

  # Renders cells that have been searched in the appropriate color
  def render_visited
    outputs.solids << state.visited.map do |cell|
      render_cell cell, visited_color
    end
  end

  # Renders the star
  def render_star
    outputs.sprites << render_cell(state.star, { path: 'star.png' })
  end

  def render_cell cell, attrs
    {
      x: cell.x * grid.cell_size,
      y: cell.y * grid.cell_size,
      w: grid.cell_size,
      h: grid.cell_size
    }.merge attrs
  end

  # In code, the cells are represented as 1x1 rectangles
  # When drawn, the cells are larger than 1x1 rectangles
  # This method is used to scale up cells, and lines
  # Objects are scaled up according to the grid.cell_size variable
  # This allows for easy customization of the visual scale of the grid
  def scale_up(cell)
    # Prevents the original value of cell from being edited
    cell = cell.clone

    # If cell is just an x and y coordinate
    if cell.size == 2
      # Add a width and height of 1
      cell << 1
      cell << 1
    end

    # Scale all the values up
    cell.map! { |value| value * grid.cell_size }

    # Returns the scaled up cell
    cell
  end

  # This method processes user input every tick
  # This method allows the user to use the buttons, slider, and edit the grid
  # There are 2 types of input:
  #   Button Input
  #   Click and Drag Input
  #
  #   Button Input is used for the backward step and forward step buttons
  #   Input is detected by mouse up within the bounds of the rect
  #
  #   Click and Drag Input is used for moving the star, adding walls,
  #   removing walls, and the slider
  #
  #   When the mouse is down on the star, the click_and_drag variable is set to :star
  #   While click_and_drag equals :star, the cursor's position is used to calculate the
  #   appropriate drag behavior
  #
  #   When the mouse goes up click_and_drag is set to :none
  #
  #   A variable has to be used because the star has to continue being edited even
  #   when the cursor is no longer over the star
  #
  #   Similar things occur for the other Click and Drag inputs
  def input
    # Checks whether any of the buttons are being clicked
    input_buttons

    # The detection and processing of click and drag inputs are separate
    # The program has to remember that the user is dragging an object
    # even when the mouse is no longer over that object
    detect_click_and_drag
    process_click_and_drag
  end

  # Detects and Process input for each button
  def input_buttons
    input_left_button
    input_center_button
    input_next_step_button
  end

  # Checks if the previous step button is clicked
  # If it is, it pauses the animation and moves the search one step backward
  def input_left_button
    if left_button_clicked?
      state.play = false
      state.anim_steps -= 1
      recalculate
    end
  end

  # Controls the play/pause button
  # Inverses whether the animation is playing or not when clicked
  def input_center_button
    if center_button_clicked? or inputs.keyboard.key_down.space
      state.play = !state.play
    end
  end

  # Checks if the next step button is clicked
  # If it is, it pauses the animation and moves the search one step forward
  def input_next_step_button
    if right_button_clicked?
      state.play = false
      state.anim_steps += 1
      calc
    end
  end

  # Determines what the user is editing and stores the value
  # Storing the value allows the user to continue the same edit as long as the
  # mouse left click is held
  def detect_click_and_drag
    if inputs.mouse.up
      state.click_and_drag = :none
    elsif star_clicked?
      state.click_and_drag = :star
    elsif wall_clicked?
      state.click_and_drag = :remove_wall
    elsif grid_clicked?
      state.click_and_drag = :add_wall
    elsif slider_clicked?
      state.click_and_drag = :slider
    end
  end

  # Processes click and drag based on what the user is currently dragging
  def process_click_and_drag
    if state.click_and_drag == :star
      input_star
    elsif state.click_and_drag == :remove_wall
      input_remove_wall
    elsif state.click_and_drag == :add_wall
      input_add_wall
    elsif state.click_and_drag == :slider
      input_slider
    end
  end

  # Moves the star to the grid closest to the mouse
  # Only recalculates the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def input_star
    old_star = state.star.clone
    state.star = cell_closest_to_mouse
    unless old_star == state.star
      recalculate
    end
  end

  # Removes walls that are under the cursor
  def input_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if mouse_inside_grid?
      if state.walls.key?(cell_closest_to_mouse)
        state.walls.delete(cell_closest_to_mouse)
        recalculate
      end
    end
  end

  # Adds walls at cells under the cursor
  def input_add_wall
    if mouse_inside_grid?
      unless state.walls.key?(cell_closest_to_mouse)
        state.walls[cell_closest_to_mouse] = true
        recalculate
      end
    end
  end

  # This method is called when the user is editing the slider
  # It pauses the animation and moves the white circle to the closest integer point
  # on the slider
  # Changes the step of the search to be animated
  def input_slider
    state.play = false
    mouse_x = inputs.mouse.point.x

    # Bounds the mouse_x to the closest x value on the slider line
    mouse_x = slider.x if mouse_x < slider.x
    mouse_x = slider.x + slider.w if mouse_x > slider.x + slider.w

    # Sets the current search step to the one represented by the mouse x value
    # The slider's circle moves due to the render_slider method using anim_steps
    state.anim_steps = ((mouse_x - slider.x) / slider.spacing).to_i

    recalculate
  end

  # Whenever the user edits the grid,
  # The search has to be recalculated upto the current step
  # with the current grid as the initial state of the grid
  def recalculate
    # Resets the search
    state.frontier = []
    state.visited = {}

    # Moves the animation forward one step at a time
    state.anim_steps.times { calc }
  end


  # This method moves the search forward one step
  # When the animation is playing it is called every tick
  # And called whenever the current step of the animation needs to be recalculated

  # Moves the search forward one step
  # Parameter called_from_tick is true if it is called from the tick method
  # It is false when the search is being recalculated after user editing the grid
  def calc

    # The setup to the search
    # Runs once when the there is no frontier or visited cells
    if state.frontier.empty? && state.visited.empty?
      state.frontier << state.star
      state.visited[state.star] = true
    end

    # A step in the search
    unless state.frontier.empty?
      # Takes the next frontier cell
      new_frontier = state.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do |neighbor|
        # That have not been visited and are not walls
        unless state.visited.key?(neighbor) || state.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited
          state.frontier << neighbor
          state.visited[neighbor] = true
        end
      end
    end
  end


  # Returns a list of adjacent cells
  # Used to determine what the next cells to be added to the frontier are
  def adjacent_neighbors(cell)
    neighbors = []

    neighbors << [cell.x, cell.y + 1] unless cell.y == grid.height - 1
    neighbors << [cell.x + 1, cell.y] unless cell.x == grid.width - 1
    neighbors << [cell.x, cell.y - 1] unless cell.y == 0
    neighbors << [cell.x - 1, cell.y] unless cell.x == 0

    neighbors
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse helps with this
  def cell_closest_to_mouse
    # Closest cell to the mouse
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Bound x and y to the grid
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # These methods detect when the buttons are clicked
  def left_button_clicked?
    inputs.mouse.up && inputs.mouse.point.inside_rect?(buttons.left)
  end

  def center_button_clicked?
    inputs.mouse.up && inputs.mouse.point.inside_rect?(buttons.center)
  end

  def right_button_clicked?
    inputs.mouse.up && inputs.mouse.point.inside_rect?(buttons.right)
  end

  # Signal that the user is going to be moving the slider
  # Is the mouse down on the circle of the slider?
  def slider_clicked?
    circle_x = (slider.x - slider.offset) + (state.anim_steps * slider.spacing)
    circle_y = (slider.y - slider.offset)
    circle_rect = [circle_x, circle_y, 37, 37]
    inputs.mouse.down && inputs.mouse.point.inside_rect?(circle_rect)
  end

  # Signal that the user is going to be moving the star
  def star_clicked?
    inputs.mouse.down && inputs.mouse.point.inside_rect?(scale_up(state.star))
  end

  # Signal that the user is going to be removing walls
  def wall_clicked?
    inputs.mouse.down && mouse_inside_a_wall?
  end

  # Signal that the user is going to be adding walls
  def grid_clicked?
    inputs.mouse.down && mouse_inside_grid?
  end

  # Returns whether the mouse is inside of a wall
  # Part of the condition that checks whether the user is removing a wall
  def mouse_inside_a_wall?
    state.walls.each_key do | wall |
      return true if inputs.mouse.point.inside_rect?(scale_up([wall.x, wall.y]))
    end

    false
  end

  # Returns whether the mouse is inside of a grid
  # Part of the condition that checks whether the user is adding a wall
  def mouse_inside_grid?
    inputs.mouse.point.inside_rect?(scale_up([0, 0, grid.width, grid.height]))
  end

  # Light brown
  def unvisited_color
    { r: 221, g: 212, b: 213 }
  end

  # Dark Brown
  def visited_color
    { r: 204, g: 191, b: 179 }
  end

  # Blue
  def frontier_color
    { r: 103, g: 136, b: 204 }
  end

  # Camo Green
  def wall_color
    { r: 134, g: 134, b: 120 }
  end

  # Button Background
  def gray
    { r: 190, g: 190, b: 190 }
  end

  # These methods make the code more concise
  def grid
    state.grid
  end

  def buttons
    state.buttons
  end

  def slider
    state.slider
  end
end

# Method that is called by DragonRuby periodically
# Used for updating animations and calculations
def tick args

  # Pressing r will reset the application
  if args.inputs.keyboard.key_down.r
    args.gtk.reset
    reset
    return
  end

  # Every tick, new args are passed, and the Breadth First Search tick is called
  $breadth_first_search ||= BreadthFirstSearch.new(args)
  $breadth_first_search.args = args
  $breadth_first_search.tick
end


def reset
  $breadth_first_search = nil
end

Detailed Breadth First Search - main.rb link

# ./samples/13_path_finding_algorithms/02_detailed_breadth_first_search/app/main.rb
# Contributors outside of DragonRuby who also hold Copyright:
# - Sujay Vadlakonda: https://github.com/sujayvadlakonda

# A visual demonstration of a breadth first search
# Inspired by https://www.redblobgames.com/pathfinding/a-star/introduction.html

# An animation that can respond to user input in real time

# A breadth first search expands in all directions one step at a time
# The frontier is a queue of cells to be expanded from
# The visited hash allows quick lookups of cells that have been expanded from
# The walls hash allows quick lookup of whether a cell is a wall

# The breadth first search starts by adding the red star to the frontier array
# and marking it as visited
# Each step a cell is removed from the front of the frontier array (queue)
# Unless the neighbor is a wall or visited, it is added to the frontier array
# The neighbor is then marked as visited

# The frontier is blue
# Visited cells are light brown
# Walls are camo green
# Even when walls are visited, they will maintain their wall color

# This search numbers the order in which new cells are explored
# The next cell from where the search will continue is highlighted yellow
# And the cells that will be considered for expansion are in semi-transparent green

# The star can be moved by clicking and dragging
# Walls can be added and removed by clicking and dragging

class DetailedBreadthFirstSearch
  attr_gtk

  def initialize(args)
    # Variables to edit the size and appearance of the grid
    # Freely customizable to user's liking
    args.state.grid.width     = 9
    args.state.grid.height    = 4
    args.state.grid.cell_size = 90

    # Stores which step of the animation is being rendered
    # When the user moves the star or messes with the walls,
    # the breadth first search is recalculated up to this step
    args.state.anim_steps = 0

    # At some step the animation will end,
    # and further steps won't change anything (the whole grid will be explored)
    # This step is roughly the grid's width * height
    # When anim_steps equals max_steps no more calculations will occur
    # and the slider will be at the end
    args.state.max_steps  = args.state.grid.width * args.state.grid.height

    # The location of the star and walls of the grid
    # They can be modified to have a different initial grid
    # Walls are stored in a hash for quick look up when doing the search
    args.state.star       = [3, 2]
    args.state.walls      = {}

    # Variables that are used by the breadth first search
    # Storing cells that the search has visited, prevents unnecessary steps
    # Expanding the frontier of the search in order makes the search expand
    # from the center outward
    args.state.visited    = {}
    args.state.frontier   = []
    args.state.cell_numbers = []



    # What the user is currently editing on the grid
    # Possible values are: :none, :slider, :star, :remove_wall, :add_wall

    # We store this value, because we want to remember the value even when
    # the user's cursor is no longer over what they're interacting with, but
    # they are still clicking down on the mouse.
    args.state.click_and_drag = :none

    # The x, y, w, h values for the buttons
    # Allow easy movement of the buttons location
    # A centralized location to get values to detect input and draw the buttons
    # Editing these values might mean needing to edit the label offsets
    # which can be found in the appropriate render button methods
    args.state.buttons.left  = [450, 600, 160, 50]
    args.state.buttons.right = [610, 600, 160, 50]

    # The variables below are related to the slider
    # They allow the user to customize them
    # They also give a central location for the render and input methods to get
    # information from
    # x & y are the coordinates of the leftmost part of the slider line
    args.state.slider.x = 400
    args.state.slider.y = 675
    # This is the width of the line
    args.state.slider.w = 360
    # This is the offset for the circle
    # Allows the center of the circle to be on the line,
    # as opposed to the upper right corner
    args.state.slider.offset = 20
    # This is the spacing between each of the notches on the slider
    # Notches are places where the circle can rest on the slider line
    # There needs to be a notch for each step before the maximum number of steps
    args.state.slider.spacing = args.state.slider.w.to_f / args.state.max_steps.to_f
  end

  # This method is called every frame/tick
  # Every tick, the current state of the search is rendered on the screen,
  # User input is processed, and
  def tick
    render
    input
  end

  # This method is called from tick and renders everything every tick
  def render
    render_buttons
    render_slider

    render_background
    render_visited
    render_frontier
    render_walls
    render_star

    render_highlights
    render_cell_numbers
  end

  # The methods below subdivide the task of drawing everything to the screen

  # Draws the buttons that move the search backward or forward
  # These buttons are rendered so the user knows where to click to move the search
  def render_buttons
    render_left_button
    render_right_button
  end

  # Renders the button which steps the search backward
  # Shows the user where to click to move the search backward
  def render_left_button
    # Draws the gray button, and a black border
    # The border separates the buttons visually
    outputs.solids  << [buttons.left, gray]
    outputs.borders << [buttons.left]

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    label_x = buttons.left.x + 05
    label_y = buttons.left.y + 35
    outputs.labels  << [label_x, label_y, "< Step backward"]
  end

  # Renders the button which steps the search forward
  # Shows the user where to click to move the search forward
  def render_right_button
    # Draws the gray button, and a black border
    # The border separates the buttons visually
    outputs.solids  << [buttons.right, gray]
    outputs.borders << [buttons.right]

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    label_x = buttons.right.x + 10
    label_y = buttons.right.y + 35
    outputs.labels  << [label_x, label_y, "Step forward >"]
  end

  # Draws the slider so the user can move it and see the progress of the search
  def render_slider
    # Using primitives hides the line under the white circle of the slider
    # Draws the line
    outputs.primitives << [slider.x, slider.y, slider.x + slider.w, slider.y].line
    # The circle needs to be offset so that the center of the circle
    # overlaps the line instead of the upper right corner of the circle
    # The circle's x value is also moved based on the current seach step
    circle_x = (slider.x - slider.offset) + (state.anim_steps * slider.spacing)
    circle_y = (slider.y - slider.offset)
    circle_rect = [circle_x, circle_y, 37, 37]
    outputs.primitives << [circle_rect, 'circle-white.png'].sprite
  end

  # Draws what the grid looks like with nothing on it
  # Which is a bunch of unvisited cells
  # Drawn first so other things can draw on top of it
  def render_background
    render_unvisited

    # The grid lines make the cells appear separate
    render_grid_lines
  end

  # Draws a rectangle the size of the entire grid to represent unvisited cells
  # Unvisited cells are the default cell
  def render_unvisited
    background = [0, 0, grid.width, grid.height]
    outputs.solids << scale_up(background).merge(unvisited_color)
  end

  # Draws grid lines to show the division of the grid into cells
  def render_grid_lines
    outputs.lines << (0..grid.width).map do |x|
      scale_up(vertical_line(x)).merge(grid_line_color)
    end
    outputs.lines << (0..grid.height).map do |y|
      scale_up(horizontal_line(y)).merge(grid_line_color)
    end
  end

  # Easy way to get a vertical line given an index
  def vertical_line column
    [column, 0, 0, grid.height]
  end

  # Easy way to get a horizontal line given an index
  def horizontal_line row
    [0, row, grid.width, 0]
  end

  # Draws the area that is going to be searched from
  # The frontier is the most outward parts of the search
  def render_frontier
    state.frontier.each do |cell|
      outputs.solids << scale_up(cell).merge(frontier_color)
    end
  end

  # Draws the walls
  def render_walls
    state.walls.each_key do |wall|
      outputs.solids << scale_up(wall).merge(wall_color)
    end
  end

  # Renders cells that have been searched in the appropriate color
  def render_visited
    state.visited.each_key do |cell|
      outputs.solids << scale_up(cell).merge(visited_color)
    end
  end

  # Renders the star
  def render_star
    outputs.sprites << scale_up(state.star).merge({ path: 'star.png' })
  end

  # Cells have a number rendered in them based on when they were explored
  # This is based off of their index in the cell_numbers array
  # Cells are added to this array the same time they are added to the frontier array
  def render_cell_numbers
    state.cell_numbers.each_with_index do |cell, index|
      # Math that approx centers the number in the cell
      label_x = (cell.x * grid.cell_size) + grid.cell_size / 2 - 5
      label_y = (cell.y * grid.cell_size) + (grid.cell_size / 2) + 5

      outputs.labels << [label_x, label_y, (index + 1).to_s]
    end
  end

  # The next frontier to be expanded is highlighted yellow
  # Its adjacent non-wall neighbors have their border highlighted green
  # This is to show the user how the search expands
  def render_highlights
    return if state.frontier.empty?

    # Highlight the next frontier to be expanded yellow
    next_frontier = state.frontier[0]
    outputs.solids << scale_up(next_frontier).merge(highlighter_yellow)

    # Neighbors have a semi-transparent green layer over them
    # Unless the neighbor is a wall
    adjacent_neighbors(next_frontier).each do |neighbor|
      unless state.walls.key?(neighbor)
        outputs.solids << scale_up(neighbor).merge(highlighter_green)
      end
    end
  end


  # Cell Size is used when rendering to allow the grid to be scaled up or down
  # Cells in the frontier array and visited hash and walls hash are stored as x & y
  # Scaling up cells and lines when rendering allows omitting of width and height
  def scale_up(cell)
    if cell.size == 2
      return {
        x: cell.x * grid.cell_size,
        y: cell.y * grid.cell_size,
        w: grid.cell_size,
        h: grid.cell_size
      }
    else
      return {
        x: cell.x * grid.cell_size,
        y: cell.y * grid.cell_size,
        w: cell.w * grid.cell_size,
        h: cell.h * grid.cell_size
      }
    end
  end


  # This method processes user input every tick
  # This method allows the user to use the buttons, slider, and edit the grid
  # There are 2 types of input:
  #   Button Input
  #   Click and Drag Input
  #
  #   Button Input is used for the backward step and forward step buttons
  #   Input is detected by mouse up within the bounds of the rect
  #
  #   Click and Drag Input is used for moving the star, adding walls,
  #   removing walls, and the slider
  #
  #   When the mouse is down on the star, the click_and_drag variable is set to :star
  #   While click_and_drag equals :star, the cursor's position is used to calculate the
  #   appropriate drag behavior
  #
  #   When the mouse goes up click_and_drag is set to :none
  #
  #   A variable has to be used because the star has to continue being edited even
  #   when the cursor is no longer over the star
  #
  #   Similar things occur for the other Click and Drag inputs
  def input
    # Processes inputs for the buttons
    input_buttons

    # Detects which if any click and drag input is occurring
    detect_click_and_drag

    # Does the appropriate click and drag input based on the click_and_drag variable
    process_click_and_drag
  end

  # Detects and Process input for each button
  def input_buttons
    input_left_button
    input_right_button
  end

  # Checks if the previous step button is clicked
  # If it is, it pauses the animation and moves the search one step backward
  def input_left_button
    if left_button_clicked?
      unless state.anim_steps == 0
        state.anim_steps -= 1
        recalculate
      end
    end
  end

  # Checks if the next step button is clicked
  # If it is, it pauses the animation and moves the search one step forward
  def input_right_button
    if right_button_clicked?
      unless state.anim_steps == state.max_steps
        state.anim_steps += 1
        # Although normally recalculate would be called here
        # because the right button only moves the search forward
        # We can just do that
        calc
      end
    end
  end

  # Whenever the user edits the grid,
  # The search has to be recalculated upto the current step

  def recalculate
    # Resets the search
    state.frontier = []
    state.visited = {}
    state.cell_numbers = []

    # Moves the animation forward one step at a time
    state.anim_steps.times { calc }
  end


  # Determines what the user is clicking and planning on dragging
  # Click and drag input is initiated by a click on the appropriate item
  # and ended by mouse up
  # Storing the value allows the user to continue the same edit as long as the
  # mouse left click is held
  def detect_click_and_drag
    if inputs.mouse.up
      state.click_and_drag = :none
    elsif star_clicked?
      state.click_and_drag = :star
    elsif wall_clicked?
      state.click_and_drag = :remove_wall
    elsif grid_clicked?
      state.click_and_drag = :add_wall
    elsif slider_clicked?
      state.click_and_drag = :slider
    end
  end

  # Processes input based on what the user is currently dragging
  def process_click_and_drag
    if state.click_and_drag == :slider
      input_slider
    elsif state.click_and_drag == :star
      input_star
    elsif state.click_and_drag == :remove_wall
      input_remove_wall
    elsif state.click_and_drag == :add_wall
      input_add_wall
    end
  end

  # This method is called when the user is dragging the slider
  # It moves the current animation step to the point represented by the slider
  def input_slider
    mouse_x = inputs.mouse.point.x

    # Bounds the mouse_x to the closest x value on the slider line
    mouse_x = slider.x if mouse_x < slider.x
    mouse_x = slider.x + slider.w if mouse_x > slider.x + slider.w

    # Sets the current search step to the one represented by the mouse x value
    # The slider's circle moves due to the render_slider method using anim_steps
    state.anim_steps = ((mouse_x - slider.x) / slider.spacing).to_i

    recalculate
  end

  # Moves the star to the grid closest to the mouse
  # Only recalculates the search if the star changes position
  # Called whenever the user is dragging the star
  def input_star
    old_star = state.star.clone
    state.star = cell_closest_to_mouse
    unless old_star == state.star
      recalculate
    end
  end

  # Removes walls that are under the cursor
  def input_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if mouse_inside_grid?
      if state.walls.key?(cell_closest_to_mouse)
        state.walls.delete(cell_closest_to_mouse)
        recalculate
      end
    end
  end

  # Adds walls at cells under the cursor
  def input_add_wall
    # Adds a wall to the hash
    # We can use the grid closest to mouse, because the cursor is inside the grid
    if mouse_inside_grid?
      unless state.walls.key?(cell_closest_to_mouse)
        state.walls[cell_closest_to_mouse] = true
        recalculate
      end
    end
  end

  # This method moves the search forward one step
  # When the animation is playing it is called every tick
  # And called whenever the current step of the animation needs to be recalculated

  # Moves the search forward one step
  # Parameter called_from_tick is true if it is called from the tick method
  # It is false when the search is being recalculated after user editing the grid
  def calc
    # The setup to the search
    # Runs once when the there is no frontier or visited cells
    if state.frontier.empty? && state.visited.empty?
      state.frontier << state.star
      state.visited[state.star] = true
    end

    # A step in the search
    unless state.frontier.empty?
      # Takes the next frontier cell
      new_frontier = state.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do |neighbor|
        # That have not been visited and are not walls
        unless state.visited.key?(neighbor) || state.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited
          state.frontier << neighbor
          state.visited[neighbor] = true

          # Also assign them a frontier number
          state.cell_numbers << neighbor
        end
      end
    end
  end


  # Returns a list of adjacent cells
  # Used to determine what the next cells to be added to the frontier are
  def adjacent_neighbors cell
    neighbors = []

    neighbors << [cell.x, cell.y + 1] unless cell.y == grid.height - 1
    neighbors << [cell.x + 1, cell.y] unless cell.x == grid.width - 1
    neighbors << [cell.x, cell.y - 1] unless cell.y == 0
    neighbors << [cell.x - 1, cell.y] unless cell.x == 0

    neighbors
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the grid closest to the mouse helps with this
  def cell_closest_to_mouse
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    [x, y]
  end


  # These methods detect when the buttons are clicked
  def left_button_clicked?
    (inputs.mouse.up && inputs.mouse.point.inside_rect?(buttons.left)) || inputs.keyboard.key_up.left
  end

  def right_button_clicked?
    (inputs.mouse.up && inputs.mouse.point.inside_rect?(buttons.right)) || inputs.keyboard.key_up.right
  end

  # Signal that the user is going to be moving the slider
  def slider_clicked?
    circle_x = (slider.x - slider.offset) + (state.anim_steps * slider.spacing)
    circle_y = (slider.y - slider.offset)
    circle_rect = [circle_x, circle_y, 37, 37]
    inputs.mouse.down && inputs.mouse.point.inside_rect?(circle_rect)
  end

  # Signal that the user is going to be moving the star
  def star_clicked?
    inputs.mouse.down && inputs.mouse.point.inside_rect?(scale_up(state.star))
  end

  # Signal that the user is going to be removing walls
  def wall_clicked?
    inputs.mouse.down && mouse_inside_a_wall?
  end

  # Signal that the user is going to be adding walls
  def grid_clicked?
    inputs.mouse.down && mouse_inside_grid?
  end

  # Returns whether the mouse is inside of a wall
  # Part of the condition that checks whether the user is removing a wall
  def mouse_inside_a_wall?
    state.walls.each_key do | wall |
      return true if inputs.mouse.point.inside_rect?(scale_up(wall))
    end

    false
  end

  # Returns whether the mouse is inside of a grid
  # Part of the condition that checks whether the user is adding a wall
  def mouse_inside_grid?
    inputs.mouse.point.inside_rect?(scale_up([0, 0, grid.width, grid.height]))
  end

  # These methods provide handy aliases to colors

  # Light brown
  def unvisited_color
    { r: 221, g: 212, b: 213 }
  end

  # Black
  def grid_line_color
    { r: 255, g: 255, b: 255 }
  end

  # Dark Brown
  def visited_color
    { r: 204, g: 191, b: 179 }
  end

  # Blue
  def frontier_color
    { r: 103, g: 136, b: 204 }
  end

  # Camo Green
  def wall_color
    { r: 134, g: 134, b: 120 }
  end

  # Next frontier to be expanded
  def highlighter_yellow
    { r: 214, g: 231, b: 125 }
  end

  # The neighbors of the next frontier to be expanded
  def highlighter_green
    { r: 65, g: 191, b: 127, a: 70 }
  end

  # Button background
  def gray
    [190, 190, 190]
  end

  # These methods make the code more concise
  def grid
    state.grid
  end

  def buttons
    state.buttons
  end

  def slider
    state.slider
  end
end


def tick args
  # Pressing r resets the program
  if args.inputs.keyboard.key_down.r
    args.gtk.reset
    reset
    return
  end

  $detailed_breadth_first_search ||= DetailedBreadthFirstSearch.new(args)
  $detailed_breadth_first_search.args = args
  $detailed_breadth_first_search.tick
end


def reset
  $detailed_breadth_first_search = nil
end

Breadcrumbs - main.rb link

# ./samples/13_path_finding_algorithms/03_breadcrumbs/app/main.rb
# Contributors outside of DragonRuby who also hold Copyright:
# - Sujay Vadlakonda: https://github.com/sujayvadlakonda

# This program is inspired by https://www.redblobgames.com/pathfinding/a-star/introduction.html

class Breadcrumbs
  attr_gtk

  # This method is called every frame/tick
  # Every tick, the current state of the search is rendered on the screen,
  # User input is processed, and
  # The next step in the search is calculated
  def tick
    defaults
    # If the grid has not been searched
    if search.came_from.empty?
      calc
      # Calc Path
    end
    render
    input
  end

  def defaults
    # Variables to edit the size and appearance of the grid
    # Freely customizable to user's liking
    grid.width     ||= 30
    grid.height    ||= 15
    grid.cell_size ||= 40
    grid.rect      ||= [0, 0, grid.width, grid.height]

    # The location of the star and walls of the grid
    # They can be modified to have a different initial grid
    # Walls are stored in a hash for quick look up when doing the search
    grid.star   ||= [2, 8]
    grid.target ||= [10, 5]
    grid.walls  ||= {
      [3, 3] => true,
      [3, 4] => true,
      [3, 5] => true,
      [3, 6] => true,
      [3, 7] => true,
      [3, 8] => true,
      [3, 9] => true,
      [3, 10] => true,
      [3, 11] => true,
      [4, 3] => true,
      [4, 4] => true,
      [4, 5] => true,
      [4, 6] => true,
      [4, 7] => true,
      [4, 8] => true,
      [4, 9] => true,
      [4, 10] => true,
      [4, 11] => true,
      [13, 0] => true,
      [13, 1] => true,
      [13, 2] => true,
      [13, 3] => true,
      [13, 4] => true,
      [13, 5] => true,
      [13, 6] => true,
      [13, 7] => true,
      [13, 8] => true,
      [13, 9] => true,
      [13, 10] => true,
      [14, 0] => true,
      [14, 1] => true,
      [14, 2] => true,
      [14, 3] => true,
      [14, 4] => true,
      [14, 5] => true,
      [14, 6] => true,
      [14, 7] => true,
      [14, 8] => true,
      [14, 9] => true,
      [14, 10] => true,
      [21, 8] => true,
      [21, 9] => true,
      [21, 10] => true,
      [21, 11] => true,
      [21, 12] => true,
      [21, 13] => true,
      [21, 14] => true,
      [22, 8] => true,
      [22, 9] => true,
      [22, 10] => true,
      [22, 11] => true,
      [22, 12] => true,
      [22, 13] => true,
      [22, 14] => true,
      [23, 8] => true,
      [23, 9] => true,
      [24, 8] => true,
      [24, 9] => true,
      [25, 8] => true,
      [25, 9] => true,
    }

    # Variables that are used by the breadth first search
    # Storing cells that the search has visited, prevents unnecessary steps
    # Expanding the frontier of the search in order makes the search expand
    # from the center outward

    # The cells from which the search is to expand
    search.frontier              ||= []
    # A hash of where each cell was expanded from
    # The key is a cell, and the value is the cell it came from
    search.came_from             ||= {}
    # Cells that are part of the path from the target to the star
    search.path                  ||= {}

    # What the user is currently editing on the grid
    # We store this value, because we want to remember the value even when
    # the user's cursor is no longer over what they're interacting with, but
    # they are still clicking down on the mouse.
    state.current_input ||= :none
  end

  def calc
    # Setup the search to start from the star
    search.frontier << grid.star
    search.came_from[grid.star] = nil

    # Until there are no more cells to expand from
    until search.frontier.empty?
      # Takes the next frontier cell
      new_frontier = search.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do |neighbor|
        # That have not been visited and are not walls
        unless search.came_from.has_key?(neighbor) || grid.walls.has_key?(neighbor)
          # Add them to the frontier and mark them as visited in the first grid
          # Unless the target has been visited
          # Add the neighbor to the frontier and remember which cell it came from
          search.frontier << neighbor
          search.came_from[neighbor] = new_frontier
        end
      end
    end
  end


  # Draws everything onto the screen
  def render
    render_background
    # render_heat_map
    render_walls
    # render_path
    # render_labels
    render_arrows
    render_star
    render_target
    unless grid.walls.has_key?(grid.target)
      render_trail
    end
  end

  def render_trail(current_cell=grid.target)
    return if current_cell == grid.star
    parent_cell = search.came_from[current_cell]
    if current_cell && parent_cell
      outputs.lines << [(current_cell.x + 0.5) * grid.cell_size, (current_cell.y + 0.5) * grid.cell_size,
      (parent_cell.x + 0.5) * grid.cell_size, (parent_cell.y + 0.5) * grid.cell_size, purple]

    end
    render_trail(parent_cell)
  end

  def render_arrows
    search.came_from.each do |child, parent|
      if parent && child
        arrow_cell = [(child.x + parent.x) / 2, (child.y + parent.y) / 2]
        if parent.x > child.x # If the parent cell is to the right of the child cell
          # Point arrow right
          outputs.sprites << scale_up(arrow_cell).merge({ path: 'arrow.png', angle: 0})
        elsif parent.x < child.x # If the parent cell is to the right of the child cell
          outputs.sprites << scale_up(arrow_cell).merge({ path: 'arrow.png', angle: 180})
        elsif parent.y > child.y # If the parent cell is to the right of the child cell
          outputs.sprites << scale_up(arrow_cell).merge({ path: 'arrow.png', angle: 90})
        elsif parent.y < child.y # If the parent cell is to the right of the child cell
          outputs.sprites << scale_up(arrow_cell).merge({ path: 'arrow.png', angle: 270})
        end
      end
    end
  end

  # The methods below subdivide the task of drawing everything to the screen

  # Draws what the grid looks like with nothing on it
  def render_background
    render_unvisited
    render_grid_lines
  end

  # Draws both grids
  def render_unvisited
    outputs.solids << scale_up(grid.rect).merge(unvisited_color)
  end

  # Draws grid lines to show the division of the grid into cells
  def render_grid_lines
    outputs.lines << (0..grid.width).map { |x| vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| horizontal_line(y) }
  end

  # Easy way to draw vertical lines given an index
  def vertical_line x
    line = { x: x, y: 0, w: 0, h: grid.height }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Easy way to draw horizontal lines given an index
  def horizontal_line y
    line = { x: 0, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Draws the walls on both grids
  def render_walls
    outputs.solids << grid.walls.map do |key, value|
      scale_up(key).merge(wall_color)
    end
  end

  # Renders the star on both grids
  def render_star
    outputs.sprites << scale_up(grid.star).merge({ path: 'star.png' })
  end

  # Renders the target on both grids
  def render_target
    outputs.sprites << scale_up(grid.target).merge({ path: 'target.png'})
  end

  # Labels the grids
  def render_labels
    outputs.labels << [200, 625, "Without early exit"]
  end

  # Renders the path based off of the search.path hash
  def render_path
    # If the star and target are disconnected there will only be one path
    # The path should not render in that case
    unless search.path.size == 1
      search.path.each_key do | cell |
        # Renders path on both grids
        outputs.solids << [scale_up(cell), path_color]
      end
    end
  end

  # Calculates the path from the target to the star after the search is over
  # Relies on the came_from hash
  # Fills the search.path hash, which is later rendered on screen
  def calc_path
    endpoint = grid.target
    while endpoint
      search.path[endpoint] = true
      endpoint = search.came_from[endpoint]
    end
  end

  # In code, the cells are represented as 1x1 rectangles
  # When drawn, the cells are larger than 1x1 rectangles
  # This method is used to scale up cells, and lines
  # Objects are scaled up according to the grid.cell_size variable
  # This allows for easy customization of the visual scale of the grid
  def scale_up(cell)
    x = cell.x * grid.cell_size
    y = cell.y * grid.cell_size
    w = cell.w.zero? ? grid.cell_size : cell.w * grid.cell_size
    h = cell.h.zero? ? grid.cell_size : cell.h * grid.cell_size
    { x: x, y: y, w: w, h: h }
  end

  # This method processes user input every tick
  # Any method with "1" is related to the first grid
  # Any method with "2" is related to the second grid
  def input
    # The program has to remember that the user is dragging an object
    # even when the mouse is no longer over that object
    # So detecting input and processing input is separate
    # detect_input
    # process_input
    if inputs.mouse.up
      state.current_input = :none
    elsif star_clicked?
      state.current_input = :star
    end

    if mouse_inside_grid?
      unless grid.target == cell_closest_to_mouse
        grid.target = cell_closest_to_mouse
      end
      if state.current_input == :star
        unless grid.star == cell_closest_to_mouse
          grid.star = cell_closest_to_mouse
        end
      end
    end
  end

  # Determines what the user is editing and stores the value
  # Storing the value allows the user to continue the same edit as long as the
  # mouse left click is held
  def detect_input
    # When the mouse is up, nothing is being edited
    if inputs.mouse.up
      state.current_input = :none
    # When the star in the no second grid is clicked
    elsif star_clicked?
      state.current_input = :star
    # When the target in the no second grid is clicked
    elsif target_clicked?
      state.current_input = :target
    # When a wall in the first grid is clicked
    elsif wall_clicked?
      state.current_input = :remove_wall
    # When the first grid is clicked
    elsif grid_clicked?
      state.current_input = :add_wall
    end
  end

  # Processes click and drag based on what the user is currently dragging
  def process_input
    if state.current_input == :star
      input_star
    elsif state.current_input == :target
      input_target
    elsif state.current_input == :remove_wall
      input_remove_wall
    elsif state.current_input == :add_wall
      input_add_wall
    end
  end

  # Moves the star to the cell closest to the mouse in the first grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def input_star
    old_star = grid.star.clone
    grid.star = cell_closest_to_mouse
    unless old_star == grid.star
      reset_search
    end
  end

  # Moves the target to the grid closest to the mouse in the first grid
  # Only reset_searchs the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def input_target
    old_target = grid.target.clone
    grid.target = cell_closest_to_mouse
    unless old_target == grid.target
      reset_search
    end
  end

  # Removes walls in the first grid that are under the cursor
  def input_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if mouse_inside_grid?
      if grid.walls.key?(cell_closest_to_mouse)
        grid.walls.delete(cell_closest_to_mouse)
        reset_search
      end
    end
  end

  # Adds a wall in the first grid in the cell the mouse is over
  def input_add_wall
    if mouse_inside_grid?
      unless grid.walls.key?(cell_closest_to_mouse)
        grid.walls[cell_closest_to_mouse] = true
        reset_search
      end
    end
  end


  # Whenever the user edits the grid,
  # The search has to be reset_searchd upto the current step
  # with the current grid as the initial state of the grid
  def reset_search
    # Reset_Searchs the search
    search.frontier  = []
    search.came_from = {}
    search.path      = {}
  end


  # Returns a list of adjacent cells
  # Used to determine what the next cells to be added to the frontier are
  def adjacent_neighbors(cell)
    neighbors = []

    # Gets all the valid neighbors into the array
    # From southern neighbor, clockwise
    neighbors << [cell.x, cell.y - 1] unless cell.y == 0
    neighbors << [cell.x - 1, cell.y] unless cell.x == 0
    neighbors << [cell.x, cell.y + 1] unless cell.y == grid.height - 1
    neighbors << [cell.x + 1, cell.y] unless cell.x == grid.width - 1

    # Sorts the neighbors so the rendered path is a zigzag path
    # Cells in a diagonal direction are given priority
    # Comment this line to see the difference
    neighbors = neighbors.sort_by { |neighbor_x, neighbor_y|  proximity_to_star(neighbor_x, neighbor_y) }

    neighbors
  end

  # Finds the vertical and horizontal distance of a cell from the star
  # and returns the larger value
  # This method is used to have a zigzag pattern in the rendered path
  # A cell that is [5, 5] from the star,
  # is explored before over a cell that is [0, 7] away.
  # So, if possible, the search tries to go diagonal (zigzag) first
  def proximity_to_star(x, y)
    distance_x = (grid.star.x - x).abs
    distance_y = (grid.star.y - y).abs

    if distance_x > distance_y
      return distance_x
    else
      return distance_y
    end
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse helps with this
  def cell_closest_to_mouse
    # Closest cell to the mouse in the first grid
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Bound x and y to the grid
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # Signal that the user is going to be moving the star from the first grid
  def star_clicked?
    inputs.mouse.down && inputs.mouse.point.inside_rect?(scale_up(grid.star))
  end

  # Signal that the user is going to be moving the target from the first grid
  def target_clicked?
    inputs.mouse.down && inputs.mouse.point.inside_rect?(scale_up(grid.target))
  end

  # Signal that the user is going to be adding walls from the first grid
  def grid_clicked?
    inputs.mouse.down && mouse_inside_grid?
  end

  # Returns whether the mouse is inside of the first grid
  # Part of the condition that checks whether the user is adding a wall
  def mouse_inside_grid?
    inputs.mouse.point.inside_rect?(scale_up(grid.rect))
  end

  # These methods provide handy aliases to colors

  # Light brown
  def unvisited_color
    { r: 221, g: 212, b: 213 }
  end

  # Camo Green
  def wall_color
    { r: 134, g: 134, b: 120 }
  end

  # Pastel White
  def path_color
    [231, 230, 228]
  end

  def red
    [255, 0, 0]
  end

  def purple
    [149, 64, 191]
  end

  # Makes code more concise
  def grid
    state.grid
  end

  def search
    state.search
  end
end

# Method that is called by DragonRuby periodically
# Used for updating animations and calculations
def tick args

  # Pressing r will reset the application
  if args.inputs.keyboard.key_down.r
    args.gtk.reset
    reset
    return
  end

  # Every tick, new args are passed, and the Breadth First Search tick is called
  $breadcrumbs ||= Breadcrumbs.new
  $breadcrumbs.args = args
  $breadcrumbs.tick
end


def reset
  $breadcrumbs = nil
end

 #  # Representation of how far away visited cells are from the star
 #  # Replaces the render_visited method
 #  # Visually demonstrates the effectiveness of early exit for pathfinding
 #  def render_heat_map
 #    # THIS CODE NEEDS SOME FIXING DUE TO REFACTORING
 #    search.came_from.each_key do | cell |
 #      distance = (grid.star.x - visited_cell.x).abs + (state.star.y - visited_cell.y).abs
 #      max_distance = grid.width + grid.height
 #      alpha = 255.to_i * distance.to_i / max_distance.to_i
 #      outputs.solids << [scale_up(visited_cell), red, alpha]
 #      # outputs.solids << [early_exit_scale_up(visited_cell), red, alpha]
 #    end
 #  end

Early Exit - main.rb link

# ./samples/13_path_finding_algorithms/04_early_exit/app/main.rb
# Contributors outside of DragonRuby who also hold Copyright:
# - Sujay Vadlakonda: https://github.com/sujayvadlakonda

# Comparison of a breadth first search with and without early exit
# Inspired by https://www.redblobgames.com/pathfinding/a-star/introduction.html

# Demonstrates the exploration difference caused by early exit
# Also demonstrates how breadth first search is used for path generation

# The left grid is a breadth first search without early exit
# The right grid is a breadth first search with early exit
# The red squares represent how far the search expanded
# The darker the red, the farther the search proceeded
# Comparison of the heat map reveals how much searching can be saved by early exit
# The white path shows path generation via breadth first search
class EarlyExitBreadthFirstSearch
  attr_gtk

  # This method is called every frame/tick
  # Every tick, the current state of the search is rendered on the screen,
  # User input is processed, and
  # The next step in the search is calculated
  def tick
    defaults
    # If the grid has not been searched
    if state.visited.empty?
      # Complete the search
      state.max_steps.times { step }
      # And calculate the path
      calc_path
    end
    render
    input
  end

  def defaults
    # Variables to edit the size and appearance of the grid
    # Freely customizable to user's liking
    grid.width     ||= 15
    grid.height    ||= 15
    grid.cell_size ||= 40
    grid.rect      ||= [0, 0, grid.width, grid.height]

    # At some step the animation will end,
    # and further steps won't change anything (the whole grid.widthill be explored)
    # This step is roughly the grid's width * height
    # When anim_steps equals max_steps no more calculations will occur
    # and the slider will be at the end
    state.max_steps  ||= args.state.grid.width * args.state.grid.height

    # The location of the star and walls of the grid
    # They can be modified to have a different initial grid
    # Walls are stored in a hash for quick look up when doing the search
    state.star   ||= [2, 8]
    state.target ||= [10, 5]
    state.walls  ||= {}

    # Variables that are used by the breadth first search
    # Storing cells that the search has visited, prevents unnecessary steps
    # Expanding the frontier of the search in order makes the search expand
    # from the center outward

    # Visited cells in the first grid
    state.visited               ||= {}
    # Visited cells in the second grid
    state.early_exit_visited    ||= {}
    # The cells from which the search is to expand
    state.frontier              ||= []
    # A hash of where each cell was expanded from
    # The key is a cell, and the value is the cell it came from
    state.came_from             ||= {}
    # Cells that are part of the path from the target to the star
    state.path                  ||= {}

    # What the user is currently editing on the grid
    # We store this value, because we want to remember the value even when
    # the user's cursor is no longer over what they're interacting with, but
    # they are still clicking down on the mouse.
    state.current_input ||= :none
  end

  # Draws everything onto the screen
  def render
    render_background
    render_heat_map
    render_walls
    render_path
    render_star
    render_target
    render_labels
  end

  # The methods below subdivide the task of drawing everything to the screen

  # Draws what the grid looks like with nothing on it
  def render_background
    render_unvisited
    render_grid_lines
  end

  # Draws both grids
  def render_unvisited
    outputs.solids << scale_up(grid.rect).merge(unvisited_color)
    outputs.solids << early_exit_scale_up(grid.rect).merge(unvisited_color)
  end

  # Draws grid lines to show the division of the grid into cells
  def render_grid_lines
    outputs.lines << (0..grid.width).map { |x| vertical_line(x) }
    outputs.lines << (0..grid.width).map { |x| early_exit_vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| horizontal_line(y) }
    outputs.lines << (0..grid.height).map { |y| early_exit_horizontal_line(y) }
  end

  # Easy way to draw vertical lines given an index
  def vertical_line x
    line = { x: x, y: 0, w: 0, h: grid.height }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Easy way to draw horizontal lines given an index
  def horizontal_line y
    line = { x: 0, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Easy way to draw vertical lines given an index
  def early_exit_vertical_line x
    vertical_line(x + grid.width + 1)
  end

  # Easy way to draw horizontal lines given an index
  def early_exit_horizontal_line y
    line = { x: grid.width + 1, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Draws the walls on both grids
  def render_walls
    state.walls.each_key do |wall|
      outputs.solids << scale_up(wall).merge(wall_color)
      outputs.solids << early_exit_scale_up(wall).merge(wall_color)
    end
  end

  # Renders the star on both grids
  def render_star
    outputs.sprites << scale_up(state.star).merge({path: 'star.png'})
    outputs.sprites << early_exit_scale_up(state.star).merge({path: 'star.png'})
  end

  # Renders the target on both grids
  def render_target
    outputs.sprites << scale_up(state.target).merge({path: 'target.png'})
    outputs.sprites << early_exit_scale_up(state.target).merge({path: 'target.png'})
  end

  # Labels the grids
  def render_labels
    outputs.labels << [200, 625, "Without early exit"]
    outputs.labels << [875, 625, "With early exit"]
  end

  # Renders the path based off of the state.path hash
  def render_path
    # If the star and target are disconnected there will only be one path
    # The path should not render in that case
    unless state.path.size == 1
      state.path.each_key do | cell |
        # Renders path on both grids
        outputs.solids << scale_up(cell).merge(path_color)
        outputs.solids << early_exit_scale_up(cell).merge(path_color)
      end
    end
  end

  # Calculates the path from the target to the star after the search is over
  # Relies on the came_from hash
  # Fills the state.path hash, which is later rendered on screen
  def calc_path
    endpoint = state.target
    while endpoint
      state.path[endpoint] = true
      endpoint = state.came_from[endpoint]
    end
  end

  # Representation of how far away visited cells are from the star
  # Replaces the render_visited method
  # Visually demonstrates the effectiveness of early exit for pathfinding
  def render_heat_map
    state.visited.each_key do | visited_cell |
      distance = (state.star.x - visited_cell.x).abs + (state.star.y - visited_cell.y).abs
      max_distance = grid.width + grid.height
      alpha = 255.to_i * distance.to_i / max_distance.to_i
      heat_color = red.merge({a: alpha })
      outputs.solids << scale_up(visited_cell).merge(heat_color)
    end

    state.early_exit_visited.each_key do | visited_cell |
      distance = (state.star.x - visited_cell.x).abs + (state.star.y - visited_cell.y).abs
      max_distance = grid.width + grid.height
      alpha = 255.to_i * distance.to_i / max_distance.to_i
      heat_color = red.merge({a: alpha })
      outputs.solids << early_exit_scale_up(visited_cell).merge(heat_color)
    end
  end

  # Translates the given cell grid.width + 1 to the right and then scales up
  # Used to draw cells for the second grid
  # This method does not work for lines,
  # so separate methods exist for the grid lines
  def early_exit_scale_up(cell)
    cell_clone = cell.clone
    cell_clone.x += grid.width + 1
    scale_up(cell_clone)
  end

  # In code, the cells are represented as 1x1 rectangles
  # When drawn, the cells are larger than 1x1 rectangles
  # This method is used to scale up cells, and lines
  # Objects are scaled up according to the grid.cell_size variable
  # This allows for easy customization of the visual scale of the grid
  def scale_up(cell)
    if cell.size == 2
      return {
        x: cell.x * grid.cell_size,
        y: cell.y * grid.cell_size,
        w: grid.cell_size,
        h: grid.cell_size
      }
    else
      return {
        x: cell.x * grid.cell_size,
        y: cell.y * grid.cell_size,
        w: cell.w * grid.cell_size,
        h: cell.h * grid.cell_size
      }
    end
  end

  # This method processes user input every tick
  # Any method with "1" is related to the first grid
  # Any method with "2" is related to the second grid
  def input
    # The program has to remember that the user is dragging an object
    # even when the mouse is no longer over that object
    # So detecting input and processing input is separate
    detect_input
    process_input
  end

  # Determines what the user is editing and stores the value
  # Storing the value allows the user to continue the same edit as long as the
  # mouse left click is held
  def detect_input
    # When the mouse is up, nothing is being edited
    if inputs.mouse.up
      state.current_input = :none
    # When the star in the no second grid is clicked
    elsif star_clicked?
      state.current_input = :star
    # When the star in the second grid is clicked
    elsif star2_clicked?
      state.current_input = :star2
    # When the target in the no second grid is clicked
    elsif target_clicked?
      state.current_input = :target
    # When the target in the second grid is clicked
    elsif target2_clicked?
      state.current_input = :target2
    # When a wall in the first grid is clicked
    elsif wall_clicked?
      state.current_input = :remove_wall
    # When a wall in the second grid is clicked
    elsif wall2_clicked?
      state.current_input = :remove_wall2
    # When the first grid is clicked
    elsif grid_clicked?
      state.current_input = :add_wall
    # When the second grid is clicked
    elsif grid2_clicked?
      state.current_input = :add_wall2
    end
  end

  # Processes click and drag based on what the user is currently dragging
  def process_input
    if state.current_input == :star
      input_star
    elsif state.current_input == :star2
      input_star2
    elsif state.current_input == :target
      input_target
    elsif state.current_input == :target2
      input_target2
    elsif state.current_input == :remove_wall
      input_remove_wall
    elsif state.current_input == :remove_wall2
      input_remove_wall2
    elsif state.current_input == :add_wall
      input_add_wall
    elsif state.current_input == :add_wall2
      input_add_wall2
    end
  end

  # Moves the star to the cell closest to the mouse in the first grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def input_star
    old_star = state.star.clone
    state.star = cell_closest_to_mouse
    unless old_star == state.star
      reset_search
    end
  end

  # Moves the star to the cell closest to the mouse in the second grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def input_star2
    old_star = state.star.clone
    state.star = cell_closest_to_mouse2
    unless old_star == state.star
      reset_search
    end
  end

  # Moves the target to the grid closest to the mouse in the first grid
  # Only reset_searchs the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def input_target
    old_target = state.target.clone
    state.target = cell_closest_to_mouse
    unless old_target == state.target
      reset_search
    end
  end

  # Moves the target to the cell closest to the mouse in the second grid
  # Only reset_searchs the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def input_target2
    old_target = state.target.clone
    state.target = cell_closest_to_mouse2
    unless old_target == state.target
      reset_search
    end
  end

  # Removes walls in the first grid that are under the cursor
  def input_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if mouse_inside_grid?
      if state.walls.key?(cell_closest_to_mouse)
        state.walls.delete(cell_closest_to_mouse)
        reset_search
      end
    end
  end

  # Removes walls in the second grid that are under the cursor
  def input_remove_wall2
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if mouse_inside_grid2?
      if state.walls.key?(cell_closest_to_mouse2)
        state.walls.delete(cell_closest_to_mouse2)
        reset_search
      end
    end
  end

  # Adds a wall in the first grid in the cell the mouse is over
  def input_add_wall
    if mouse_inside_grid?
      unless state.walls.key?(cell_closest_to_mouse)
        state.walls[cell_closest_to_mouse] = true
        reset_search
      end
    end
  end


  # Adds a wall in the second grid in the cell the mouse is over
  def input_add_wall2
    if mouse_inside_grid2?
      unless state.walls.key?(cell_closest_to_mouse2)
        state.walls[cell_closest_to_mouse2] = true
        reset_search
      end
    end
  end

  # Whenever the user edits the grid,
  # The search has to be reset_searchd upto the current step
  # with the current grid as the initial state of the grid
  def reset_search
    # Reset_Searchs the search
    state.frontier  = []
    state.visited   = {}
    state.early_exit_visited   = {}
    state.came_from = {}
    state.path      = {}
  end

  # Moves the search forward one step
  def step
    # The setup to the search
    # Runs once when there are no visited cells
    if state.visited.empty?
      state.visited[state.star] = true
      state.early_exit_visited[state.star] = true
      state.frontier << state.star
      state.came_from[state.star] = nil
    end

    # A step in the search
    unless state.frontier.empty?
      # Takes the next frontier cell
      new_frontier = state.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do |neighbor|
        # That have not been visited and are not walls
        unless state.visited.key?(neighbor) || state.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited in the first grid
          state.visited[neighbor] = true
          # Unless the target has been visited
          unless state.visited.key?(state.target)
            # Mark the neighbor as visited in the second grid as well
            state.early_exit_visited[neighbor] = true
          end

          # Add the neighbor to the frontier and remember which cell it came from
          state.frontier << neighbor
          state.came_from[neighbor] = new_frontier
        end
      end
    end
  end


  # Returns a list of adjacent cells
  # Used to determine what the next cells to be added to the frontier are
  def adjacent_neighbors(cell)
    neighbors = []

    # Gets all the valid neighbors into the array
    # From southern neighbor, clockwise
    neighbors << [cell.x, cell.y - 1] unless cell.y == 0
    neighbors << [cell.x - 1, cell.y] unless cell.x == 0
    neighbors << [cell.x, cell.y + 1] unless cell.y == grid.height - 1
    neighbors << [cell.x + 1, cell.y] unless cell.x == grid.width - 1

    # Sorts the neighbors so the rendered path is a zigzag path
    # Cells in a diagonal direction are given priority
    # Comment this line to see the difference
    neighbors = neighbors.sort_by { |neighbor_x, neighbor_y|  proximity_to_star(neighbor_x, neighbor_y) }

    neighbors
  end

  # Finds the vertical and horizontal distance of a cell from the star
  # and returns the larger value
  # This method is used to have a zigzag pattern in the rendered path
  # A cell that is [5, 5] from the star,
  # is explored before over a cell that is [0, 7] away.
  # So, if possible, the search tries to go diagonal (zigzag) first
  def proximity_to_star(x, y)
    distance_x = (state.star.x - x).abs
    distance_y = (state.star.y - y).abs

    if distance_x > distance_y
      return distance_x
    else
      return distance_y
    end
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse helps with this
  def cell_closest_to_mouse
    # Closest cell to the mouse in the first grid
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Bound x and y to the grid
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse in the second grid helps with this
  def cell_closest_to_mouse2
    # Closest cell grid to the mouse in the second
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Translate the cell to the first grid
    x -= grid.width + 1
    # Bound x and y to the first grid
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # Signal that the user is going to be moving the star from the first grid
  def star_clicked?
    inputs.mouse.down && inputs.mouse.point.inside_rect?(scale_up(state.star))
  end

  # Signal that the user is going to be moving the star from the second grid
  def star2_clicked?
    inputs.mouse.down && inputs.mouse.point.inside_rect?(early_exit_scale_up(state.star))
  end

  # Signal that the user is going to be moving the target from the first grid
  def target_clicked?
    inputs.mouse.down && inputs.mouse.point.inside_rect?(scale_up(state.target))
  end

  # Signal that the user is going to be moving the target from the second grid
  def target2_clicked?
    inputs.mouse.down && inputs.mouse.point.inside_rect?(early_exit_scale_up(state.target))
  end

  # Signal that the user is going to be removing walls from the first grid
  def wall_clicked?
    inputs.mouse.down && mouse_inside_wall?
  end

  # Signal that the user is going to be removing walls from the second grid
  def wall2_clicked?
    inputs.mouse.down && mouse_inside_wall2?
  end

  # Signal that the user is going to be adding walls from the first grid
  def grid_clicked?
    inputs.mouse.down && mouse_inside_grid?
  end

  # Signal that the user is going to be adding walls from the second grid
  def grid2_clicked?
    inputs.mouse.down && mouse_inside_grid2?
  end

  # Returns whether the mouse is inside of a wall in the first grid
  # Part of the condition that checks whether the user is removing a wall
  def mouse_inside_wall?
    state.walls.each_key do | wall |
      return true if inputs.mouse.point.inside_rect?(scale_up(wall))
    end

    false
  end

  # Returns whether the mouse is inside of a wall in the second grid
  # Part of the condition that checks whether the user is removing a wall
  def mouse_inside_wall2?
    state.walls.each_key do | wall |
      return true if inputs.mouse.point.inside_rect?(early_exit_scale_up(wall))
    end

    false
  end

  # Returns whether the mouse is inside of the first grid
  # Part of the condition that checks whether the user is adding a wall
  def mouse_inside_grid?
    inputs.mouse.point.inside_rect?(scale_up(grid.rect))
  end

  # Returns whether the mouse is inside of the second grid
  # Part of the condition that checks whether the user is adding a wall
  def mouse_inside_grid2?
    inputs.mouse.point.inside_rect?(early_exit_scale_up(grid.rect))
  end

  # These methods provide handy aliases to colors

  # Light brown
  def unvisited_color
    [221, 212, 213]
    { r: 221, g: 212, b: 213 }
  end

  # Camo Green
  def wall_color
    { r: 134, g: 134, b: 120 }
  end

  # Pastel White
  def path_color
    { r: 231, g: 230, b: 228 }
  end

  def red
    { r: 255, g: 0, b: 0 }
  end

  # Makes code more concise
  def grid
    state.grid
  end
end

# Method that is called by DragonRuby periodically
# Used for updating animations and calculations
def tick args

  # Pressing r will reset the application
  if args.inputs.keyboard.key_down.r
    args.gtk.reset
    reset
    return
  end

  # Every tick, new args are passed, and the Breadth First Search tick is called
  $early_exit_breadth_first_search ||= EarlyExitBreadthFirstSearch.new
  $early_exit_breadth_first_search.args = args
  $early_exit_breadth_first_search.tick
end


def reset
  $early_exit_breadth_first_search = nil
end

Dijkstra - main.rb link

# ./samples/13_path_finding_algorithms/05_dijkstra/app/main.rb
# Contributors outside of DragonRuby who also hold Copyright:
# - Sujay Vadlakonda: https://github.com/sujayvadlakonda

# Demonstrates how Dijkstra's Algorithm allows movement costs to be considered

# Inspired by https://www.redblobgames.com/pathfinding/a-star/introduction.html

# The first grid is a breadth first search with an early exit.
# It shows a heat map of all the cells that were visited by the search and their relative distance.

# The second grid is an implementation of Dijkstra's algorithm.
# Light green cells have 5 times the movement cost of regular cells.
# The heat map will darken based on movement cost.

# Dark green cells are walls, and the search cannot go through them.
class Movement_Costs
  attr_gtk

  # This method is called every frame/tick
  # Every tick, the current state of the search is rendered on the screen,
  # User input is processed, and
  # The next step in the search is calculated
  def tick
    defaults
    render
    input
    calc
  end

  def defaults
    # Variables to edit the size and appearance of the grid
    # Freely customizable to user's liking
    grid.width     ||= 10
    grid.height    ||= 10
    grid.cell_size ||= 60
    grid.rect      ||= [0, 0, grid.width, grid.height]

    # The location of the star and walls of the grid
    # They can be modified to have a different initial grid
    # Walls are stored in a hash for quick look up when doing the search
    state.star   ||= [1, 5]
    state.target ||= [8, 4]
    state.walls  ||= {[1, 1] => true, [2, 1] => true, [3, 1] => true, [1, 2] => true, [2, 2] => true, [3, 2] => true}
    state.hills  ||= {
      [4, 1] => true,
      [5, 1] => true,
      [4, 2] => true,
      [5, 2] => true,
      [6, 2] => true,
      [4, 3] => true,
      [5, 3] => true,
      [6, 3] => true,
      [3, 4] => true,
      [4, 4] => true,
      [5, 4] => true,
      [6, 4] => true,
      [7, 4] => true,
      [3, 5] => true,
      [4, 5] => true,
      [5, 5] => true,
      [6, 5] => true,
      [7, 5] => true,
      [4, 6] => true,
      [5, 6] => true,
      [6, 6] => true,
      [7, 6] => true,
      [4, 7] => true,
      [5, 7] => true,
      [6, 7] => true,
      [4, 8] => true,
      [5, 8] => true,
    }

    # What the user is currently editing on the grid
    # We store this value, because we want to remember the value even when
    # the user's cursor is no longer over what they're interacting with, but
    # they are still clicking down on the mouse.
    state.user_input ||= :none

    # Values that are used for the breadth first search
    # Keeping track of what cells were visited prevents counting cells multiple times
    breadth_first_search.visited    ||= {}
    # The cells from which the breadth first search will expand
    breadth_first_search.frontier   ||= []
    # Keeps track of which cell all cells were searched from
    # Used to recreate the path from the target to the star
    breadth_first_search.came_from  ||= {}

    # Keeps track of the movement cost so far to be at a cell
    # Allows the costs of new cells to be quickly calculated
    # Also doubles as a way to check if cells have already been visited
    dijkstra_search.cost_so_far ||= {}
    # The cells from which the Dijkstra search will expand
    dijkstra_search.frontier    ||= []
    # Keeps track of which cell all cells were searched from
    # Used to recreate the path from the target to the star
    dijkstra_search.came_from   ||= {}
  end

  # Draws everything onto the screen
  def render
    render_background

    render_heat_maps

    render_star
    render_target
    render_hills
    render_walls

    render_paths
  end
  # The methods below subdivide the task of drawing everything to the screen

  # Draws what the grid looks like with nothing on it
  def render_background
    render_unvisited
    render_grid_lines
    render_labels
  end

  # Draws two rectangles the size of the grid in the default cell color
  # Used as part of the background
  def render_unvisited
    outputs.solids << scale_up(grid.rect).merge(unvisited_color)
    outputs.solids << move_and_scale_up(grid.rect).merge(unvisited_color)
  end

  # Draws grid lines to show the division of the grid into cells
  def render_grid_lines
    outputs.lines << (0..grid.width).map { |x| vertical_line(x) }
    outputs.lines << (0..grid.width).map { |x| shifted_vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| horizontal_line(y) }
    outputs.lines << (0..grid.height).map { |y| shifted_horizontal_line(y) }
  end

  # A line the size of the grid, multiplied by the cell size for rendering
  def vertical_line x
    line = { x: x, y: 0, w: 0, h: grid.height }
    line.transform_values { |v| v * grid.cell_size }
  end

  # A line the size of the grid, multiplied by the cell size for rendering
  def horizontal_line y
    line = { x: 0, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Translate vertical line by the size of the grid and 1
  def shifted_vertical_line x
    vertical_line(x + grid.width + 1)
  end

  # Get horizontal line and shift to the right
  def shifted_horizontal_line y
    line = { x: grid.width + 1, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Labels the grids
  def render_labels
    outputs.labels << [175, 650, "Number of steps", 3]
    outputs.labels << [925, 650, "Distance", 3]
  end

  def render_paths
    render_breadth_first_search_path
    render_dijkstra_path
  end

  def render_heat_maps
    render_breadth_first_search_heat_map
    render_dijkstra_heat_map
  end

  # This heat map shows the cells explored by the breadth first search and how far they are from the star.
  def render_breadth_first_search_heat_map
    # For each cell explored
    breadth_first_search.visited.each_key do | visited_cell |
      # Find its distance from the star
      distance = (state.star.x - visited_cell.x).abs + (state.star.y - visited_cell.y).abs
      max_distance = grid.width + grid.height
      # Get it as a percent of the maximum distance and scale to 255 for use as an alpha value
      alpha = 255.to_i * distance.to_i / max_distance.to_i
      heat_color = red.merge({a: alpha })
      outputs.solids << scale_up(visited_cell).merge(heat_color)
    end
  end

  def render_breadth_first_search_path
    # If the search found the target
    if breadth_first_search.visited.has_key?(state.target)
      # Start from the target
      endpoint = state.target
      # And the cell it came from
      next_endpoint = breadth_first_search.came_from[endpoint]
      while endpoint && next_endpoint
        # Draw a path between these two cells
        path = get_path_between(endpoint, next_endpoint)
        outputs.solids << scale_up(path).merge(path_color)
        # And get the next pair of cells
        endpoint = next_endpoint
        next_endpoint = breadth_first_search.came_from[endpoint]
        # Continue till there are no more cells
      end
    end
  end

  def render_dijkstra_heat_map
    dijkstra_search.cost_so_far.each do |visited_cell, cost|
      max_cost = (grid.width + grid.height) #* 5
      alpha = 255.to_i * cost.to_i / max_cost.to_i
      heat_color = red.merge({a: alpha})
      outputs.solids << move_and_scale_up(visited_cell).merge(heat_color)
    end
  end

  def render_dijkstra_path
    # If the search found the target
    if dijkstra_search.came_from.has_key?(state.target)
      # Get the target and the cell it came from
      endpoint = state.target
      next_endpoint = dijkstra_search.came_from[endpoint]
      while endpoint && next_endpoint
        # Draw a path between them
        path = get_path_between(endpoint, next_endpoint)
        outputs.solids << move_and_scale_up(path).merge(path_color)

        # Shift one cell down the path
        endpoint = next_endpoint
        next_endpoint = dijkstra_search.came_from[endpoint]

        # Repeat till the end of the path
      end
    end
  end

  # Renders the star on both grids
  def render_star
    outputs.sprites << scale_up(state.star).merge({path: 'star.png'})
    outputs.sprites << move_and_scale_up(state.star).merge({path: 'star.png'})
  end

  # Renders the target on both grids
  def render_target
    outputs.sprites << scale_up(state.target).merge({path: 'target.png'})
    outputs.sprites << move_and_scale_up(state.target).merge({path: 'target.png'})
  end

  def render_hills
    state.hills.each_key do |hill|
      outputs.solids << scale_up(hill).merge(hill_color)
      outputs.solids << move_and_scale_up(hill).merge(hill_color)
    end
  end

  # Draws the walls on both grids
  def render_walls
    state.walls.each_key do |wall|
      outputs.solids << scale_up(wall).merge(wall_color)
      outputs.solids << move_and_scale_up(wall).merge(wall_color)
    end
  end

  def get_path_between(cell_one, cell_two)
    path = nil
    if cell_one.x == cell_two.x
      if cell_one.y < cell_two.y
        path = [cell_one.x + 0.3, cell_one.y + 0.3, 0.4, 1.4]
      else
        path = [cell_two.x + 0.3, cell_two.y + 0.3, 0.4, 1.4]
      end
    else
      if cell_one.x < cell_two.x
        path = [cell_one.x + 0.3, cell_one.y + 0.3, 1.4, 0.4]
      else
        path = [cell_two.x + 0.3, cell_two.y + 0.3, 1.4, 0.4]
      end
    end
    path
  end

  # Translates the given cell grid.width + 1 to the right and then scales up
  # Used to draw cells for the second grid
  # This method does not work for lines,
  # so separate methods exist for the grid lines
  def move_and_scale_up(cell)
    cell_clone = cell.clone
    cell_clone.x += grid.width + 1
    scale_up(cell_clone)
  end

  # In code, the cells are represented as 1x1 rectangles
  # When drawn, the cells are larger than 1x1 rectangles
  # This method is used to scale up cells, and lines
  # Objects are scaled up according to the grid.cell_size variable
  # This allows for easy customization of the visual scale of the grid
  def scale_up(cell)
    if cell.size == 2
      return {
        x: cell.x * grid.cell_size,
        y: cell.y * grid.cell_size,
        w: grid.cell_size,
        h: grid.cell_size
      }
    else
      return {
        x: cell.x * grid.cell_size,
        y: cell.y * grid.cell_size,
        w: cell.w * grid.cell_size,
        h: cell.h * grid.cell_size
      }
    end
  end

  # Handles user input every tick so the grid can be edited
  # Separate input detection and processing is needed
  # For example: Adding walls is started by clicking down on a hill,
  # but the mouse doesn't need to remain over hills to add walls
  def input
    # If the mouse was lifted this tick
    if inputs.mouse.up
      # Set current input to none
      state.user_input = :none
    end

    # If the mouse was clicked this tick
    if inputs.mouse.down
      # Determine what the user is editing and edit the state.user_input variable
      determine_input
    end

    # Process user input based on user_input variable and current mouse position
    process_input
  end

  # Determines what the user is editing and stores the value
  # This method is called the tick the mouse is clicked
  # Storing the value allows the user to continue the same edit as long as the
  # mouse left click is held
  def determine_input
    # If the mouse is over the star in the first grid
    if mouse_over_star?
      # The user is editing the star from the first grid
      state.user_input = :star
    # If the mouse is over the star in the second grid
    elsif mouse_over_star2?
      # The user is editing the star from the second grid
      state.user_input = :star2
    # If the mouse is over the target in the first grid
    elsif mouse_over_target?
      # The user is editing the target from the first grid
      state.user_input = :target
    # If the mouse is over the target in the second grid
    elsif mouse_over_target2?
      # The user is editing the target from the second grid
      state.user_input = :target2
    # If the mouse is over a wall in the first grid
    elsif mouse_over_wall?
      # The user is removing a wall from the first grid
      state.user_input = :remove_wall
    # If the mouse is over a wall in the second grid
    elsif mouse_over_wall2?
      # The user is removing a wall from the second grid
      state.user_input = :remove_wall2
    # If the mouse is over a hill in the first grid
    elsif mouse_over_hill?
      # The user is adding a wall from the first grid
      state.user_input = :add_wall
    # If the mouse is over a hill in the second grid
    elsif mouse_over_hill2?
      # The user is adding a wall from the second grid
      state.user_input = :add_wall2
    # If the mouse is over the first grid
    elsif mouse_over_grid?
      # The user is adding a hill from the first grid
      state.user_input = :add_hill
    # If the mouse is over the second grid
    elsif mouse_over_grid2?
      # The user is adding a hill from the second grid
      state.user_input = :add_hill2
    end
  end

  # Processes click and drag based on what the user is currently dragging
  def process_input
    if state.user_input == :star
      input_star
    elsif state.user_input == :star2
      input_star2
    elsif state.user_input == :target
      input_target
    elsif state.user_input == :target2
      input_target2
    elsif state.user_input == :remove_wall
      input_remove_wall
    elsif state.user_input == :remove_wall2
      input_remove_wall2
    elsif state.user_input == :add_hill
      input_add_hill
    elsif state.user_input == :add_hill2
      input_add_hill2
    elsif state.user_input == :add_wall
      input_add_wall
    elsif state.user_input == :add_wall2
      input_add_wall2
    end
  end

  # Calculates the two searches
  def calc
    # If the searches have not started
    if breadth_first_search.visited.empty?
      # Calculate the two searches
      calc_breadth_first
      calc_dijkstra
    end
  end


  def calc_breadth_first
    # Sets up the Breadth First Search
    breadth_first_search.visited[state.star]   = true
    breadth_first_search.frontier              << state.star
    breadth_first_search.came_from[state.star] = nil

    until breadth_first_search.frontier.empty?
      return if breadth_first_search.visited.key?(state.target)
      # A step in the search
      # Takes the next frontier cell
      new_frontier = breadth_first_search.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do | neighbor |
        # That have not been visited and are not walls
        unless breadth_first_search.visited.key?(neighbor) || state.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited in the first grid
          breadth_first_search.visited[neighbor] = true
          breadth_first_search.frontier << neighbor
          # Remember which cell the neighbor came from
          breadth_first_search.came_from[neighbor] = new_frontier
        end
      end
    end
  end

  # Calculates the Dijkstra Search from the beginning to the end

  def calc_dijkstra
    # The initial values for the Dijkstra search
    dijkstra_search.frontier                << [state.star, 0]
    dijkstra_search.came_from[state.star]   = nil
    dijkstra_search.cost_so_far[state.star] = 0

    # Until their are no more cells to be explored
    until dijkstra_search.frontier.empty?
      # Get the next cell to be explored from
      # We get the first element of the array which is the cell. The second element is the priority.
      current = dijkstra_search.frontier.shift[0]

      # Stop the search if we found the target
      return if current == state.target

      # For each of the neighbors
      adjacent_neighbors(current).each do | neighbor |
        # Unless this cell is a wall or has already been explored.
        unless dijkstra_search.came_from.key?(neighbor) or state.walls.key?(neighbor)
          # Calculate the movement cost of getting to this cell and memo
          new_cost = dijkstra_search.cost_so_far[current] + cost(neighbor)
          dijkstra_search.cost_so_far[neighbor] = new_cost

          # Add this neighbor to the cells too be explored
          dijkstra_search.frontier << [neighbor, new_cost]
          dijkstra_search.came_from[neighbor] = current
        end
      end

      # Sort the frontier so exploration occurs that have a low cost so far.
      # My implementation of a priority queue
      dijkstra_search.frontier = dijkstra_search.frontier.sort_by {|cell, priority| priority}
    end
  end

  def cost(cell)
    return 5 if state.hills.key? cell
    1
  end




  # Moves the star to the cell closest to the mouse in the first grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def input_star
    old_star = state.star.clone
    unless cell_closest_to_mouse == state.target
      state.star = cell_closest_to_mouse
    end
    unless old_star == state.star
      reset_search
    end
  end

  # Moves the star to the cell closest to the mouse in the second grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def input_star2
    old_star = state.star.clone
    unless cell_closest_to_mouse2 == state.target
      state.star = cell_closest_to_mouse2
    end
    unless old_star == state.star
      reset_search
    end
  end

  # Moves the target to the grid closest to the mouse in the first grid
  # Only reset_searchs the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def input_target
    old_target = state.target.clone
    unless cell_closest_to_mouse == state.star
      state.target = cell_closest_to_mouse
    end
    unless old_target == state.target
      reset_search
    end
  end

  # Moves the target to the cell closest to the mouse in the second grid
  # Only reset_searchs the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def input_target2
    old_target = state.target.clone
    unless cell_closest_to_mouse2 == state.star
      state.target = cell_closest_to_mouse2
    end
    unless old_target == state.target
      reset_search
    end
  end

  # Removes walls in the first grid that are under the cursor
  def input_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if mouse_over_grid?
      if state.walls.key?(cell_closest_to_mouse) or state.hills.key?(cell_closest_to_mouse)
        state.walls.delete(cell_closest_to_mouse)
        state.hills.delete(cell_closest_to_mouse)
        reset_search
      end
    end
  end

  # Removes walls in the second grid that are under the cursor
  def input_remove_wall2
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if mouse_over_grid2?
      if state.walls.key?(cell_closest_to_mouse2) or state.hills.key?(cell_closest_to_mouse2)
        state.walls.delete(cell_closest_to_mouse2)
        state.hills.delete(cell_closest_to_mouse2)
        reset_search
      end
    end
  end

  # Adds a hill in the first grid in the cell the mouse is over
  def input_add_hill
    if mouse_over_grid?
      unless state.hills.key?(cell_closest_to_mouse)
        state.hills[cell_closest_to_mouse] = true
        reset_search
      end
    end
  end


  # Adds a hill in the second grid in the cell the mouse is over
  def input_add_hill2
    if mouse_over_grid2?
      unless state.hills.key?(cell_closest_to_mouse2)
        state.hills[cell_closest_to_mouse2] = true
        reset_search
      end
    end
  end

  # Adds a wall in the first grid in the cell the mouse is over
  def input_add_wall
    if mouse_over_grid?
      unless state.walls.key?(cell_closest_to_mouse)
        state.hills.delete(cell_closest_to_mouse)
        state.walls[cell_closest_to_mouse] = true
        reset_search
      end
    end
  end

  # Adds a wall in the second grid in the cell the mouse is over
  def input_add_wall2
    if mouse_over_grid2?
      unless state.walls.key?(cell_closest_to_mouse2)
        state.hills.delete(cell_closest_to_mouse2)
        state.walls[cell_closest_to_mouse2] = true
        reset_search
      end
    end
  end

  # Whenever the user edits the grid,
  # The search has to be reset_searchd upto the current step
  # with the current grid as the initial state of the grid
  def reset_search
    breadth_first_search.visited    = {}
    breadth_first_search.frontier   = []
    breadth_first_search.came_from  = {}

    dijkstra_search.frontier    = []
    dijkstra_search.came_from   = {}
    dijkstra_search.cost_so_far = {}
  end



  # Returns a list of adjacent cells
  # Used to determine what the next cells to be added to the frontier are
  def adjacent_neighbors(cell)
    neighbors = []

    # Gets all the valid neighbors into the array
    # From southern neighbor, clockwise
    neighbors << [cell.x    , cell.y - 1] unless cell.y == 0
    neighbors << [cell.x - 1, cell.y    ] unless cell.x == 0
    neighbors << [cell.x    , cell.y + 1] unless cell.y == grid.height - 1
    neighbors << [cell.x + 1, cell.y    ] unless cell.x == grid.width - 1

    # Sorts the neighbors so the rendered path is a zigzag path
    # Cells in a diagonal direction are given priority
    # Comment this line to see the difference
    neighbors = neighbors.sort_by { |neighbor_x, neighbor_y|  proximity_to_star(neighbor_x, neighbor_y) }

    neighbors
  end

  # Finds the vertical and horizontal distance of a cell from the star
  # and returns the larger value
  # This method is used to have a zigzag pattern in the rendered path
  # A cell that is [5, 5] from the star,
  # is explored before over a cell that is [0, 7] away.
  # So, if possible, the search tries to go diagonal (zigzag) first
  def proximity_to_star(x, y)
    distance_x = (state.star.x - x).abs
    distance_y = (state.star.y - y).abs

    if distance_x > distance_y
      return distance_x
    else
      return distance_y
    end
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse helps with this
  def cell_closest_to_mouse
    # Closest cell to the mouse in the first grid
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Bound x and y to the grid
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse in the second grid helps with this
  def cell_closest_to_mouse2
    # Closest cell grid to the mouse in the second
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Translate the cell to the first grid
    x -= grid.width + 1
    # Bound x and y to the first grid
    x = 0 if x < 0
    y = 0 if y < 0
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # Signal that the user is going to be moving the star from the first grid
  def mouse_over_star?
    inputs.mouse.point.inside_rect?(scale_up(state.star))
  end

  # Signal that the user is going to be moving the star from the second grid
  def mouse_over_star2?
    inputs.mouse.point.inside_rect?(move_and_scale_up(state.star))
  end

  # Signal that the user is going to be moving the target from the first grid
  def mouse_over_target?
    inputs.mouse.point.inside_rect?(scale_up(state.target))
  end

  # Signal that the user is going to be moving the target from the second grid
  def mouse_over_target2?
    inputs.mouse.point.inside_rect?(move_and_scale_up(state.target))
  end

  # Signal that the user is going to be removing walls from the first grid
  def mouse_over_wall?
    state.walls.each_key do | wall |
      return true if inputs.mouse.point.inside_rect?(scale_up(wall))
    end

    false
  end

  # Signal that the user is going to be removing walls from the second grid
  def mouse_over_wall2?
    state.walls.each_key do | wall |
      return true if inputs.mouse.point.inside_rect?(move_and_scale_up(wall))
    end

    false
  end

  # Signal that the user is going to be removing hills from the first grid
  def mouse_over_hill?
    state.hills.each_key do | hill |
      return true if inputs.mouse.point.inside_rect?(scale_up(hill))
    end

    false
  end

  # Signal that the user is going to be removing hills from the second grid
  def mouse_over_hill2?
    state.hills.each_key do | hill |
      return true if inputs.mouse.point.inside_rect?(move_and_scale_up(hill))
    end

    false
  end

  # Signal that the user is going to be adding walls from the first grid
  def mouse_over_grid?
    inputs.mouse.point.inside_rect?(scale_up(grid.rect))
  end

  # Signal that the user is going to be adding walls from the second grid
  def mouse_over_grid2?
    inputs.mouse.point.inside_rect?(move_and_scale_up(grid.rect))
  end

  # These methods provide handy aliases to colors

  # Light brown
  def unvisited_color
    { r: 221, g: 212, b: 213 }
  end

  # Camo Green
  def wall_color
    { r: 134, g: 134, b: 120 }
  end

  # Pastel White
  def path_color
    { r: 231, g: 230, b: 228 }
  end

  def red
    { r: 255, g: 0, b: 0 }
  end

  # A Green
  def hill_color
    { r: 139, g: 173, b: 132 }
  end

  # Makes code more concise
  def grid
    state.grid
  end

  def breadth_first_search
    state.breadth_first_search
  end

  def dijkstra_search
    state.dijkstra_search
  end
end

# Method that is called by DragonRuby periodically
# Used for updating animations and calculations
def tick args

  # Pressing r will reset the application
  if args.inputs.keyboard.key_down.r
    args.gtk.reset
    reset
    return
  end

  # Every tick, new args are passed, and the Dijkstra tick method is called
  $movement_costs ||= Movement_Costs.new
  $movement_costs.args = args
  $movement_costs.tick
end


def reset
  $movement_costs = nil
end

Heuristic - main.rb link

# ./samples/13_path_finding_algorithms/06_heuristic/app/main.rb
# Contributors outside of DragonRuby who also hold Copyright:
# - Sujay Vadlakonda: https://github.com/sujayvadlakonda

# This program is inspired by https://www.redblobgames.com/pathfinding/a-star/introduction.html
# The effectiveness of the Heuristic search algorithm is shown through this demonstration.
# Notice that both searches find the shortest path
# The heuristic search, however, explores less of the grid, and is therefore faster.
# The heuristic search prioritizes searching cells that are closer to the target.
# Make sure to look at the Heuristic with walls program to see some of the downsides of the heuristic algorithm.

class Heuristic
  attr_gtk

  def tick
    defaults
    render
    input
    # If animation is playing, and max steps have not been reached
    # Move the search a step forward
    if state.play && state.current_step < state.max_steps
      # Variable that tells the program what step to recalculate up to
      state.current_step += 1
      move_searches_one_step_forward
    end
  end

  def defaults
    # Variables to edit the size and appearance of the grid
    # Freely customizable to user's liking
    grid.width     ||= 15
    grid.height    ||= 15
    grid.cell_size ||= 40
    grid.rect      ||= [0, 0, grid.width, grid.height]

    grid.star      ||= [0, 2]
    grid.target    ||= [14, 12]
    grid.walls     ||= {}
    # There are no hills in the Heuristic Search Demo

    # What the user is currently editing on the grid
    # We store this value, because we want to remember the value even when
    # the user's cursor is no longer over what they're interacting with, but
    # they are still clicking down on the mouse.
    state.user_input ||= :none

    # These variables allow the breadth first search to take place
    # Came_from is a hash with a key of a cell and a value of the cell that was expanded from to find the key.
    # Used to prevent searching cells that have already been found
    # and to trace a path from the target back to the starting point.
    # Frontier is an array of cells to expand the search from.
    # The search is over when there are no more cells to search from.
    # Path stores the path from the target to the star, once the target has been found
    # It prevents calculating the path every tick.
    bfs.came_from  ||= {}
    bfs.frontier   ||= []
    bfs.path       ||= []

    heuristic.came_from ||= {}
    heuristic.frontier  ||= []
    heuristic.path      ||= []

    # Stores which step of the animation is being rendered
    # When the user moves the star or messes with the walls,
    # the searches are recalculated up to this step
    unless state.current_step
      state.current_step = 0
    end

    # At some step the animation will end,
    # and further steps won't change anything (the whole grid will be explored)
    # This step is roughly the grid's width * height
    # When anim_steps equals max_steps no more calculations will occur
    # and the slider will be at the end
    state.max_steps = grid.width * grid.height

    # Whether the animation should play or not
    # If true, every tick moves anim_steps forward one
    # Pressing the stepwise animation buttons will pause the animation
    # An if statement instead of the ||= operator is used for assigning a boolean value.
    # The || operator does not differentiate between nil and false.
    if state.play == nil
      state.play = false
    end

    # Store the rects of the buttons that control the animation
    # They are here for user customization
    # Editing these might require recentering the text inside them
    # Those values can be found in the render_button methods
    buttons.left   = [470, 600, 50, 50]
    buttons.center = [520, 600, 200, 50]
    buttons.right  = [720, 600, 50, 50]

    # The variables below are related to the slider
    # They allow the user to customize them
    # They also give a central location for the render and input methods to get
    # information from
    # x & y are the coordinates of the leftmost part of the slider line
    slider.x = 440
    slider.y = 675
    # This is the width of the line
    slider.w = 360
    # This is the offset for the circle
    # Allows the center of the circle to be on the line,
    # as opposed to the upper right corner
    slider.offset = 20
    # This is the spacing between each of the notches on the slider
    # Notches are places where the circle can rest on the slider line
    # There needs to be a notch for each step before the maximum number of steps
    slider.spacing = slider.w.to_f / state.max_steps.to_f
  end

  # All methods with render draw stuff on the screen
  # UI has buttons, the slider, and labels
  # The search specific rendering occurs in the respective methods
  def render
    render_ui
    render_bfs
    render_heuristic
  end

  def render_ui
    render_buttons
    render_slider
    render_labels
  end

  def render_buttons
    render_left_button
    render_center_button
    render_right_button
  end

  def render_bfs
    render_bfs_grid
    render_bfs_star
    render_bfs_target
    render_bfs_visited
    render_bfs_walls
    render_bfs_frontier
    render_bfs_path
  end

  def render_heuristic
    render_heuristic_grid
    render_heuristic_star
    render_heuristic_target
    render_heuristic_visited
    render_heuristic_walls
    render_heuristic_frontier
    render_heuristic_path
  end

  # This method handles user input every tick
  def input
    # Check and handle button input
    input_buttons

    # If the mouse was lifted this tick
    if inputs.mouse.up
      # Set current input to none
      state.user_input = :none
    end

    # If the mouse was clicked this tick
    if inputs.mouse.down
      # Determine what the user is editing and appropriately edit the state.user_input variable
      determine_input
    end

    # Process user input based on user_input variable and current mouse position
    process_input
  end

  # Determines what the user is editing
  # This method is called when the mouse is clicked down
  def determine_input
    if mouse_over_slider?
      state.user_input = :slider
    # If the mouse is over the star in the first grid
    elsif bfs_mouse_over_star?
      # The user is editing the star from the first grid
      state.user_input = :bfs_star
    # If the mouse is over the star in the second grid
    elsif heuristic_mouse_over_star?
      # The user is editing the star from the second grid
      state.user_input = :heuristic_star
    # If the mouse is over the target in the first grid
    elsif bfs_mouse_over_target?
      # The user is editing the target from the first grid
      state.user_input = :bfs_target
    # If the mouse is over the target in the second grid
    elsif heuristic_mouse_over_target?
      # The user is editing the target from the second grid
      state.user_input = :heuristic_target
    # If the mouse is over a wall in the first grid
    elsif bfs_mouse_over_wall?
      # The user is removing a wall from the first grid
      state.user_input = :bfs_remove_wall
    # If the mouse is over a wall in the second grid
    elsif heuristic_mouse_over_wall?
      # The user is removing a wall from the second grid
      state.user_input = :heuristic_remove_wall
    # If the mouse is over the first grid
    elsif bfs_mouse_over_grid?
      # The user is adding a wall from the first grid
      state.user_input = :bfs_add_wall
    # If the mouse is over the second grid
    elsif heuristic_mouse_over_grid?
      # The user is adding a wall from the second grid
      state.user_input = :heuristic_add_wall
    end
  end

  # Processes click and drag based on what the user is currently dragging
  def process_input
    if state.user_input == :slider
      process_input_slider
    elsif state.user_input == :bfs_star
      process_input_bfs_star
    elsif state.user_input == :heuristic_star
      process_input_heuristic_star
    elsif state.user_input == :bfs_target
      process_input_bfs_target
    elsif state.user_input == :heuristic_target
      process_input_heuristic_target
    elsif state.user_input == :bfs_remove_wall
      process_input_bfs_remove_wall
    elsif state.user_input == :heuristic_remove_wall
      process_input_heuristic_remove_wall
    elsif state.user_input == :bfs_add_wall
      process_input_bfs_add_wall
    elsif state.user_input == :heuristic_add_wall
      process_input_heuristic_add_wall
    end
  end

  def render_slider
    # Using primitives hides the line under the white circle of the slider
    # Draws the line
    outputs.primitives << [slider.x, slider.y, slider.x + slider.w, slider.y].line
    # The circle needs to be offset so that the center of the circle
    # overlaps the line instead of the upper right corner of the circle
    # The circle's x value is also moved based on the current seach step
    circle_x = (slider.x - slider.offset) + (state.current_step * slider.spacing)
    circle_y = (slider.y - slider.offset)
    circle_rect = [circle_x, circle_y, 37, 37]
    outputs.primitives << [circle_rect, 'circle-white.png'].sprite
  end

  def render_labels
    outputs.labels << [205, 625, "Breadth First Search"]
    outputs.labels << [820, 625, "Heuristic Best-First Search"]
  end

  def render_left_button
    # Draws the button_color button, and a black border
    # The border separates the buttons visually
    outputs.solids  << [buttons.left, button_color]
    outputs.borders << [buttons.left]

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    # If the button size is changed, the label might need to be edited as well
    # to keep the label in the center of the button
    label_x = buttons.left.x + 20
    label_y = buttons.left.y + 35
    outputs.labels  << [label_x, label_y, "<"]
  end

  def render_center_button
    # Draws the button_color button, and a black border
    # The border separates the buttons visually
    outputs.solids  << [buttons.center, button_color]
    outputs.borders << [buttons.center]

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    # If the button size is changed, the label might need to be edited as well
    # to keep the label in the center of the button
    label_x    = buttons.center.x + 37
    label_y    = buttons.center.y + 35
    label_text = state.play ? "Pause Animation" : "Play Animation"
    outputs.labels << [label_x, label_y, label_text]
  end

  def render_right_button
    # Draws the button_color button, and a black border
    # The border separates the buttons visually
    outputs.solids  << [buttons.right, button_color]
    outputs.borders << [buttons.right]

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    label_x = buttons.right.x + 20
    label_y = buttons.right.y + 35
    outputs.labels  << [label_x, label_y, ">"]
  end

  def render_bfs_grid
    # A large rect the size of the grid
    outputs.solids << bfs_scale_up(grid.rect).merge(default_color)

    outputs.lines << (0..grid.width).map { |x| bfs_vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| bfs_horizontal_line(y) }
  end

  def render_heuristic_grid
    # A large rect the size of the grid
    outputs.solids << heuristic_scale_up(grid.rect).merge(default_color)

    outputs.lines << (0..grid.width).map { |x| heuristic_vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| heuristic_horizontal_line(y) }
  end

  # Returns a vertical line for a column of the first grid
  def bfs_vertical_line x
    line = { x: x, y: 0, w: 0, h: grid.height }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Returns a horizontal line for a column of the first grid
  def bfs_horizontal_line y
    line = { x: 0, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Returns a vertical line for a column of the second grid
  def heuristic_vertical_line x
    bfs_vertical_line(x + grid.width + 1)
  end

  # Returns a horizontal line for a column of the second grid
  def heuristic_horizontal_line y
    line = { x: grid.width + 1, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Renders the star on the first grid
  def render_bfs_star
    outputs.sprites << bfs_scale_up(grid.star).merge({ path: 'star.png' })
  end

  # Renders the star on the second grid
  def render_heuristic_star
    outputs.sprites << heuristic_scale_up(grid.star).merge({ path: 'star.png' })
  end

  # Renders the target on the first grid
  def render_bfs_target
    outputs.sprites << bfs_scale_up(grid.target).merge({ path: 'target.png' })
  end

  # Renders the target on the second grid
  def render_heuristic_target
    outputs.sprites << heuristic_scale_up(grid.target).merge({ path: 'target.png' })
  end

  # Renders the walls on the first grid
  def render_bfs_walls
    outputs.solids << grid.walls.map do |key, value|
      bfs_scale_up(key).merge(wall_color)
    end
  end

  # Renders the walls on the second grid
  def render_heuristic_walls
    outputs.solids << grid.walls.map do |key, value|
      heuristic_scale_up(key).merge(wall_color)
    end
  end

  # Renders the visited cells on the first grid
  def render_bfs_visited
    outputs.solids << bfs.came_from.map do |key, value|
      bfs_scale_up(key).merge(visited_color)
    end
  end

  # Renders the visited cells on the second grid
  def render_heuristic_visited
    outputs.solids << heuristic.came_from.map do |key, value|
      heuristic_scale_up(key).merge(visited_color)
    end
  end

  # Renders the frontier cells on the first grid
  def render_bfs_frontier
    outputs.solids << bfs.frontier.map do |cell|
      bfs_scale_up(cell).merge(frontier_color)
    end
  end

  # Renders the frontier cells on the second grid
  def render_heuristic_frontier
    outputs.solids << heuristic.frontier.map do |cell|
      heuristic_scale_up(cell).merge(frontier_color)
    end
  end

  # Renders the path found by the breadth first search on the first grid
  def render_bfs_path
    outputs.solids << bfs.path.map do |path|
      bfs_scale_up(path).merge(path_color)
    end
  end

  # Renders the path found by the heuristic search on the second grid
  def render_heuristic_path
    outputs.solids << heuristic.path.map do |path|
      heuristic_scale_up(path).merge(path_color)
    end
  end

  # Returns the rect for the path between two cells based on their relative positions
  def get_path_between(cell_one, cell_two)
    path = nil

    # If cell one is above cell two
    if cell_one.x == cell_two.x && cell_one.y > cell_two.y
      # Path starts from the center of cell two and moves upward to the center of cell one
      path = [cell_two.x + 0.3, cell_two.y + 0.3, 0.4, 1.4]
    # If cell one is below cell two
    elsif cell_one.x == cell_two.x && cell_one.y < cell_two.y
      # Path starts from the center of cell one and moves upward to the center of cell two
      path = [cell_one.x + 0.3, cell_one.y + 0.3, 0.4, 1.4]
    # If cell one is to the left of cell two
    elsif cell_one.x > cell_two.x && cell_one.y == cell_two.y
      # Path starts from the center of cell two and moves rightward to the center of cell one
      path = [cell_two.x + 0.3, cell_two.y + 0.3, 1.4, 0.4]
    # If cell one is to the right of cell two
    elsif cell_one.x < cell_two.x && cell_one.y == cell_two.y
      # Path starts from the center of cell one and moves rightward to the center of cell two
      path = [cell_one.x + 0.3, cell_one.y + 0.3, 1.4, 0.4]
    end

    path
  end

  # In code, the cells are represented as 1x1 rectangles
  # When drawn, the cells are larger than 1x1 rectangles
  # This method is used to scale up cells, and lines
  # Objects are scaled up according to the grid.cell_size variable
  # This allows for easy customization of the visual scale of the grid
  # This method scales up cells for the first grid
  def bfs_scale_up(cell)
    x = cell.x * grid.cell_size
    y = cell.y * grid.cell_size
    w = cell.w.zero? ? grid.cell_size : cell.w * grid.cell_size
    h = cell.h.zero? ? grid.cell_size : cell.h * grid.cell_size
    {x: x, y: y, w: w, h: h}
    # {x:, y:, w:, h:}
  end

  # Translates the given cell grid.width + 1 to the right and then scales up
  # Used to draw cells for the second grid
  # This method does not work for lines,
  # so separate methods exist for the grid lines
  def heuristic_scale_up(cell)
    # Prevents the original value of cell from being edited
    cell = cell.clone
    # Translates the cell to the second grid equivalent
    cell.x += grid.width + 1
    # Proceeds as if scaling up for the first grid
    bfs_scale_up(cell)
  end

  # Checks and handles input for the buttons
  # Called when the mouse is lifted
  def input_buttons
    input_left_button
    input_center_button
    input_right_button
  end

  # Checks if the previous step button is clicked
  # If it is, it pauses the animation and moves the search one step backward
  def input_left_button
    if left_button_clicked?
      state.play = false
      state.current_step -= 1
      recalculate_searches
    end
  end

  # Controls the play/pause button
  # Inverses whether the animation is playing or not when clicked
  def input_center_button
    if center_button_clicked? || inputs.keyboard.key_down.space
      state.play = !state.play
    end
  end

  # Checks if the next step button is clicked
  # If it is, it pauses the animation and moves the search one step forward
  def input_right_button
    if right_button_clicked?
      state.play = false
      state.current_step += 1
      move_searches_one_step_forward
    end
  end

  # These methods detect when the buttons are clicked
  def left_button_clicked?
    inputs.mouse.point.inside_rect?(buttons.left) && inputs.mouse.up
  end

  def center_button_clicked?
    inputs.mouse.point.inside_rect?(buttons.center) && inputs.mouse.up
  end

  def right_button_clicked?
    inputs.mouse.point.inside_rect?(buttons.right) && inputs.mouse.up
  end


  # Signal that the user is going to be moving the slider
  # Is the mouse over the circle of the slider?
  def mouse_over_slider?
    circle_x = (slider.x - slider.offset) + (state.current_step * slider.spacing)
    circle_y = (slider.y - slider.offset)
    circle_rect = [circle_x, circle_y, 37, 37]
    inputs.mouse.point.inside_rect?(circle_rect)
  end

  # Signal that the user is going to be moving the star from the first grid
  def bfs_mouse_over_star?
    inputs.mouse.point.inside_rect?(bfs_scale_up(grid.star))
  end

  # Signal that the user is going to be moving the star from the second grid
  def heuristic_mouse_over_star?
    inputs.mouse.point.inside_rect?(heuristic_scale_up(grid.star))
  end

  # Signal that the user is going to be moving the target from the first grid
  def bfs_mouse_over_target?
    inputs.mouse.point.inside_rect?(bfs_scale_up(grid.target))
  end

  # Signal that the user is going to be moving the target from the second grid
  def heuristic_mouse_over_target?
    inputs.mouse.point.inside_rect?(heuristic_scale_up(grid.target))
  end

  # Signal that the user is going to be removing walls from the first grid
  def bfs_mouse_over_wall?
    grid.walls.each_key do |wall|
      return true if inputs.mouse.point.inside_rect?(bfs_scale_up(wall))
    end

    false
  end

  # Signal that the user is going to be removing walls from the second grid
  def heuristic_mouse_over_wall?
    grid.walls.each_key do |wall|
      return true if inputs.mouse.point.inside_rect?(heuristic_scale_up(wall))
    end

    false
  end

  # Signal that the user is going to be adding walls from the first grid
  def bfs_mouse_over_grid?
    inputs.mouse.point.inside_rect?(bfs_scale_up(grid.rect))
  end

  # Signal that the user is going to be adding walls from the second grid
  def heuristic_mouse_over_grid?
    inputs.mouse.point.inside_rect?(heuristic_scale_up(grid.rect))
  end

  # This method is called when the user is editing the slider
  # It pauses the animation and moves the white circle to the closest integer point
  # on the slider
  # Changes the step of the search to be animated
  def process_input_slider
    state.play = false
    mouse_x = inputs.mouse.point.x

    # Bounds the mouse_x to the closest x value on the slider line
    mouse_x = slider.x if mouse_x < slider.x
    mouse_x = slider.x + slider.w if mouse_x > slider.x + slider.w

    # Sets the current search step to the one represented by the mouse x value
    # The slider's circle moves due to the render_slider method using anim_steps
    state.current_step = ((mouse_x - slider.x) / slider.spacing).to_i

    recalculate_searches
  end

  # Moves the star to the cell closest to the mouse in the first grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def process_input_bfs_star
    old_star = grid.star.clone
    unless bfs_cell_closest_to_mouse == grid.target
      grid.star = bfs_cell_closest_to_mouse
    end
    unless old_star == grid.star
      recalculate_searches
    end
  end

  # Moves the star to the cell closest to the mouse in the second grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def process_input_heuristic_star
    old_star = grid.star.clone
    unless heuristic_cell_closest_to_mouse == grid.target
      grid.star = heuristic_cell_closest_to_mouse
    end
    unless old_star == grid.star
      recalculate_searches
    end
  end

  # Moves the target to the grid closest to the mouse in the first grid
  # Only recalculate_searchess the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def process_input_bfs_target
    old_target = grid.target.clone
    unless bfs_cell_closest_to_mouse == grid.star
      grid.target = bfs_cell_closest_to_mouse
    end
    unless old_target == grid.target
      recalculate_searches
    end
  end

  # Moves the target to the cell closest to the mouse in the second grid
  # Only recalculate_searchess the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def process_input_heuristic_target
    old_target = grid.target.clone
    unless heuristic_cell_closest_to_mouse == grid.star
      grid.target = heuristic_cell_closest_to_mouse
    end
    unless old_target == grid.target
      recalculate_searches
    end
  end

  # Removes walls in the first grid that are under the cursor
  def process_input_bfs_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if bfs_mouse_over_grid?
      if grid.walls.key?(bfs_cell_closest_to_mouse)
        grid.walls.delete(bfs_cell_closest_to_mouse)
        recalculate_searches
      end
    end
  end

  # Removes walls in the second grid that are under the cursor
  def process_input_heuristic_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if heuristic_mouse_over_grid?
      if grid.walls.key?(heuristic_cell_closest_to_mouse)
        grid.walls.delete(heuristic_cell_closest_to_mouse)
        recalculate_searches
      end
    end
  end
  # Adds a wall in the first grid in the cell the mouse is over
  def process_input_bfs_add_wall
    if bfs_mouse_over_grid?
      unless grid.walls.key?(bfs_cell_closest_to_mouse)
        grid.walls[bfs_cell_closest_to_mouse] = true
        recalculate_searches
      end
    end
  end

  # Adds a wall in the second grid in the cell the mouse is over
  def process_input_heuristic_add_wall
    if heuristic_mouse_over_grid?
      unless grid.walls.key?(heuristic_cell_closest_to_mouse)
        grid.walls[heuristic_cell_closest_to_mouse] = true
        recalculate_searches
      end
    end
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse helps with this
  def bfs_cell_closest_to_mouse
    # Closest cell to the mouse in the first grid
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Bound x and y to the grid
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse in the second grid helps with this
  def heuristic_cell_closest_to_mouse
    # Closest cell grid to the mouse in the second
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Translate the cell to the first grid
    x -= grid.width + 1
    # Bound x and y to the first grid
    x = 0 if x < 0
    y = 0 if y < 0
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  def recalculate_searches
    # Reset the searches
    bfs.came_from    = {}
    bfs.frontier     = []
    bfs.path         = []
    heuristic.came_from = {}
    heuristic.frontier  = []
    heuristic.path      = []

    # Move the searches forward to the current step
    state.current_step.times { move_searches_one_step_forward }
  end

  def move_searches_one_step_forward
    bfs_one_step_forward
    heuristic_one_step_forward
  end

  def bfs_one_step_forward
    return if bfs.came_from.key?(grid.target)

    # Only runs at the beginning of the search as setup.
    if bfs.came_from.empty?
      bfs.frontier << grid.star
      bfs.came_from[grid.star] = nil
    end

    # A step in the search
    unless bfs.frontier.empty?
      # Takes the next frontier cell
      new_frontier = bfs.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do |neighbor|
        # That have not been visited and are not walls
        unless bfs.came_from.key?(neighbor) || grid.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited
          bfs.frontier << neighbor
          bfs.came_from[neighbor] = new_frontier
        end
      end
    end

    # Sort the frontier so that cells that are in a zigzag pattern are prioritized over those in an line
    # Comment this line and let a path generate to see the difference
    bfs.frontier = bfs.frontier.sort_by { |cell| proximity_to_star(cell) }

    # If the search found the target
    if bfs.came_from.key?(grid.target)
      # Calculate the path between the target and star
      bfs_calc_path
    end
  end

  # Calculates the path between the target and star for the breadth first search
  # Only called when the breadth first search finds the target
  def bfs_calc_path
    # Start from the target
    endpoint = grid.target
    # And the cell it came from
    next_endpoint = bfs.came_from[endpoint]
    while endpoint && next_endpoint
      # Draw a path between these two cells and store it
      path = get_path_between(endpoint, next_endpoint)
      bfs.path << path
      # And get the next pair of cells
      endpoint = next_endpoint
      next_endpoint = bfs.came_from[endpoint]
      # Continue till there are no more cells
    end
  end

  # Moves the heuristic search forward one step
  # Can be called from tick while the animation is playing
  # Can also be called when recalculating the searches after the user edited the grid
  def heuristic_one_step_forward
    # Stop the search if the target has been found
    return if heuristic.came_from.key?(grid.target)

    # If the search has not begun
    if heuristic.came_from.empty?
      # Setup the search to begin from the star
      heuristic.frontier << grid.star
      heuristic.came_from[grid.star] = nil
    end

    # One step in the heuristic search

    # Unless there are no more cells to explore from
    unless heuristic.frontier.empty?
      # Get the next cell to explore from
      new_frontier = heuristic.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do |neighbor|
        # That have not been visited and are not walls
        unless heuristic.came_from.key?(neighbor) || grid.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited
          heuristic.frontier << neighbor
          heuristic.came_from[neighbor] = new_frontier
        end
      end
    end

    # Sort the frontier so that cells that are in a zigzag pattern are prioritized over those in an line
    heuristic.frontier = heuristic.frontier.sort_by { |cell| proximity_to_star(cell) }
    # Sort the frontier so cells that are close to the target are then prioritized
    heuristic.frontier = heuristic.frontier.sort_by { |cell| heuristic_heuristic(cell) }

    # If the search found the target
    if heuristic.came_from.key?(grid.target)
      # Calculate the path between the target and star
      heuristic_calc_path
    end
  end

  # Returns one-dimensional absolute distance between cell and target
  # Returns a number to compare distances between cells and the target
  def heuristic_heuristic(cell)
    (grid.target.x - cell.x).abs + (grid.target.y - cell.y).abs
  end

  # Calculates the path between the target and star for the heuristic search
  # Only called when the heuristic search finds the target
  def heuristic_calc_path
    # Start from the target
    endpoint = grid.target
    # And the cell it came from
    next_endpoint = heuristic.came_from[endpoint]
    while endpoint && next_endpoint
      # Draw a path between these two cells and store it
      path = get_path_between(endpoint, next_endpoint)
      heuristic.path << path
      # And get the next pair of cells
      endpoint = next_endpoint
      next_endpoint = heuristic.came_from[endpoint]
      # Continue till there are no more cells
    end
  end

  # Returns a list of adjacent cells
  # Used to determine what the next cells to be added to the frontier are
  def adjacent_neighbors(cell)
    neighbors = []

    # Gets all the valid neighbors into the array
    # From southern neighbor, clockwise
    neighbors << [cell.x    , cell.y - 1] unless cell.y == 0
    neighbors << [cell.x - 1, cell.y    ] unless cell.x == 0
    neighbors << [cell.x    , cell.y + 1] unless cell.y == grid.height - 1
    neighbors << [cell.x + 1, cell.y    ] unless cell.x == grid.width - 1

    neighbors
  end

  # Finds the vertical and horizontal distance of a cell from the star
  # and returns the larger value
  # This method is used to have a zigzag pattern in the rendered path
  # A cell that is [5, 5] from the star,
  # is explored before over a cell that is [0, 7] away.
  # So, if possible, the search tries to go diagonal (zigzag) first
  def proximity_to_star(cell)
    distance_x = (grid.star.x - cell.x).abs
    distance_y = (grid.star.y - cell.y).abs

    [distance_x, distance_y].max
  end

  # Methods that allow code to be more concise. Subdivides args.state, which is where all variables are stored.
  def grid
    state.grid
  end

  def buttons
    state.buttons
  end

  def slider
    state.slider
  end

  def bfs
    state.bfs
  end

  def heuristic
    state.heuristic
  end

  # Descriptive aliases for colors
  def default_color
    { r: 221, g: 212, b: 213 }
  end

  def wall_color
    { r: 134, g: 134, b: 120 }
  end

  def visited_color
    { r: 204, g: 191, b: 179 }
  end

  def frontier_color
    { r: 103, g: 136, b: 204, a: 200 }
  end

  def path_color
    { r: 231, g: 230, b: 228 }
  end

  def button_color
    [190, 190, 190] # Gray
  end
end
# Method that is called by DragonRuby periodically
# Used for updating animations and calculations
def tick args

  # Pressing r will reset the application
  if args.inputs.keyboard.key_down.r
    args.gtk.reset
    reset
    return
  end

  # Every tick, new args are passed, and the Breadth First Search tick is called
  $heuristic ||= Heuristic.new
  $heuristic.args = args
  $heuristic.tick
end


def reset
  $heuristic = nil
end

Heuristic With Walls - main.rb link

# ./samples/13_path_finding_algorithms/07_heuristic_with_walls/app/main.rb
# Contributors outside of DragonRuby who also hold Copyright:
# - Sujay Vadlakonda: https://github.com/sujayvadlakonda

# This program is inspired by https://www.redblobgames.com/pathfinding/a-star/introduction.html

# This time the heuristic search still explored less of the grid, hence finishing faster.
# However, it did not find the shortest path between the star and the target.

# The only difference between this app and Heuristic is the change of the starting position.

class Heuristic_With_Walls
  attr_gtk

  def tick
    defaults
    render
    input
    # If animation is playing, and max steps have not been reached
    # Move the search a step forward
    if state.play && state.current_step < state.max_steps
      # Variable that tells the program what step to recalculate up to
      state.current_step += 1
      move_searches_one_step_forward
    end
  end

  def defaults
    # Variables to edit the size and appearance of the grid
    # Freely customizable to user's liking
    grid.width     ||= 15
    grid.height    ||= 15
    grid.cell_size ||= 40
    grid.rect      ||= [0, 0, grid.width, grid.height]

    grid.star      ||= [0, 2]
    grid.target    ||= [14, 12]
    grid.walls     ||= {
      [2, 2] => true,
      [3, 2] => true,
      [4, 2] => true,
      [5, 2] => true,
      [6, 2] => true,
      [7, 2] => true,
      [8, 2] => true,
      [9, 2] => true,
      [10, 2] => true,
      [11, 2] => true,
      [12, 2] => true,
      [12, 3] => true,
      [12, 4] => true,
      [12, 5] => true,
      [12, 6] => true,
      [12, 7] => true,
      [12, 8] => true,
      [12, 9] => true,
      [12, 10] => true,
      [12, 11] => true,
      [12, 12] => true,
      [2, 12] => true,
      [3, 12] => true,
      [4, 12] => true,
      [5, 12] => true,
      [6, 12] => true,
      [7, 12] => true,
      [8, 12] => true,
      [9, 12] => true,
      [10, 12] => true,
      [11, 12] => true,
      [12, 12] => true
    }
    # There are no hills in the Heuristic Search Demo

    # What the user is currently editing on the grid
    # We store this value, because we want to remember the value even when
    # the user's cursor is no longer over what they're interacting with, but
    # they are still clicking down on the mouse.
    state.user_input ||= :none

    # These variables allow the breadth first search to take place
    # Came_from is a hash with a key of a cell and a value of the cell that was expanded from to find the key.
    # Used to prevent searching cells that have already been found
    # and to trace a path from the target back to the starting point.
    # Frontier is an array of cells to expand the search from.
    # The search is over when there are no more cells to search from.
    # Path stores the path from the target to the star, once the target has been found
    # It prevents calculating the path every tick.
    bfs.came_from  ||= {}
    bfs.frontier   ||= []
    bfs.path       ||= []

    heuristic.came_from ||= {}
    heuristic.frontier  ||= []
    heuristic.path      ||= []

    # Stores which step of the animation is being rendered
    # When the user moves the star or messes with the walls,
    # the searches are recalculated up to this step
    unless state.current_step
      state.current_step = 0
    end

    # At some step the animation will end,
    # and further steps won't change anything (the whole grid will be explored)
    # This step is roughly the grid's width * height
    # When anim_steps equals max_steps no more calculations will occur
    # and the slider will be at the end
    state.max_steps = grid.width * grid.height

    # Whether the animation should play or not
    # If true, every tick moves anim_steps forward one
    # Pressing the stepwise animation buttons will pause the animation
    # An if statement instead of the ||= operator is used for assigning a boolean value.
    # The || operator does not differentiate between nil and false.
    if state.play == nil
      state.play = false
    end

    # Store the rects of the buttons that control the animation
    # They are here for user customization
    # Editing these might require recentering the text inside them
    # Those values can be found in the render_button methods
    buttons.left   = [470, 600, 50, 50]
    buttons.center = [520, 600, 200, 50]
    buttons.right  = [720, 600, 50, 50]

    # The variables below are related to the slider
    # They allow the user to customize them
    # They also give a central location for the render and input methods to get
    # information from
    # x & y are the coordinates of the leftmost part of the slider line
    slider.x = 440
    slider.y = 675
    # This is the width of the line
    slider.w = 360
    # This is the offset for the circle
    # Allows the center of the circle to be on the line,
    # as opposed to the upper right corner
    slider.offset = 20
    # This is the spacing between each of the notches on the slider
    # Notches are places where the circle can rest on the slider line
    # There needs to be a notch for each step before the maximum number of steps
    slider.spacing = slider.w.to_f / state.max_steps.to_f
  end

  # All methods with render draw stuff on the screen
  # UI has buttons, the slider, and labels
  # The search specific rendering occurs in the respective methods
  def render
    render_ui
    render_bfs
    render_heuristic
  end

  def render_ui
    render_buttons
    render_slider
    render_labels
  end

  def render_buttons
    render_left_button
    render_center_button
    render_right_button
  end

  def render_bfs
    render_bfs_grid
    render_bfs_star
    render_bfs_target
    render_bfs_visited
    render_bfs_walls
    render_bfs_frontier
    render_bfs_path
  end

  def render_heuristic
    render_heuristic_grid
    render_heuristic_star
    render_heuristic_target
    render_heuristic_visited
    render_heuristic_walls
    render_heuristic_frontier
    render_heuristic_path
  end

  # This method handles user input every tick
  def input
    # Check and handle button input
    input_buttons

    # If the mouse was lifted this tick
    if inputs.mouse.up
      # Set current input to none
      state.user_input = :none
    end

    # If the mouse was clicked this tick
    if inputs.mouse.down
      # Determine what the user is editing and appropriately edit the state.user_input variable
      determine_input
    end

    # Process user input based on user_input variable and current mouse position
    process_input
  end

  # Determines what the user is editing
  # This method is called when the mouse is clicked down
  def determine_input
    if mouse_over_slider?
      state.user_input = :slider
    # If the mouse is over the star in the first grid
    elsif bfs_mouse_over_star?
      # The user is editing the star from the first grid
      state.user_input = :bfs_star
    # If the mouse is over the star in the second grid
    elsif heuristic_mouse_over_star?
      # The user is editing the star from the second grid
      state.user_input = :heuristic_star
    # If the mouse is over the target in the first grid
    elsif bfs_mouse_over_target?
      # The user is editing the target from the first grid
      state.user_input = :bfs_target
    # If the mouse is over the target in the second grid
    elsif heuristic_mouse_over_target?
      # The user is editing the target from the second grid
      state.user_input = :heuristic_target
    # If the mouse is over a wall in the first grid
    elsif bfs_mouse_over_wall?
      # The user is removing a wall from the first grid
      state.user_input = :bfs_remove_wall
    # If the mouse is over a wall in the second grid
    elsif heuristic_mouse_over_wall?
      # The user is removing a wall from the second grid
      state.user_input = :heuristic_remove_wall
    # If the mouse is over the first grid
    elsif bfs_mouse_over_grid?
      # The user is adding a wall from the first grid
      state.user_input = :bfs_add_wall
    # If the mouse is over the second grid
    elsif heuristic_mouse_over_grid?
      # The user is adding a wall from the second grid
      state.user_input = :heuristic_add_wall
    end
  end

  # Processes click and drag based on what the user is currently dragging
  def process_input
    if state.user_input == :slider
      process_input_slider
    elsif state.user_input == :bfs_star
      process_input_bfs_star
    elsif state.user_input == :heuristic_star
      process_input_heuristic_star
    elsif state.user_input == :bfs_target
      process_input_bfs_target
    elsif state.user_input == :heuristic_target
      process_input_heuristic_target
    elsif state.user_input == :bfs_remove_wall
      process_input_bfs_remove_wall
    elsif state.user_input == :heuristic_remove_wall
      process_input_heuristic_remove_wall
    elsif state.user_input == :bfs_add_wall
      process_input_bfs_add_wall
    elsif state.user_input == :heuristic_add_wall
      process_input_heuristic_add_wall
    end
  end

  def render_slider
    # Using primitives hides the line under the white circle of the slider
    # Draws the line
    outputs.primitives << [slider.x, slider.y, slider.x + slider.w, slider.y].line
    # The circle needs to be offset so that the center of the circle
    # overlaps the line instead of the upper right corner of the circle
    # The circle's x value is also moved based on the current seach step
    circle_x = (slider.x - slider.offset) + (state.current_step * slider.spacing)
    circle_y = (slider.y - slider.offset)
    circle_rect = [circle_x, circle_y, 37, 37]
    outputs.primitives << [circle_rect, 'circle-white.png'].sprite
  end

  def render_labels
    outputs.labels << [205, 625, "Breadth First Search"]
    outputs.labels << [820, 625, "Heuristic Best-First Search"]
  end

  def render_left_button
    # Draws the button_color button, and a black border
    # The border separates the buttons visually
    outputs.solids  << [buttons.left, button_color]
    outputs.borders << [buttons.left]

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    # If the button size is changed, the label might need to be edited as well
    # to keep the label in the center of the button
    label_x = buttons.left.x + 20
    label_y = buttons.left.y + 35
    outputs.labels  << [label_x, label_y, "<"]
  end

  def render_center_button
    # Draws the button_color button, and a black border
    # The border separates the buttons visually
    outputs.solids  << [buttons.center, button_color]
    outputs.borders << [buttons.center]

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    # If the button size is changed, the label might need to be edited as well
    # to keep the label in the center of the button
    label_x    = buttons.center.x + 37
    label_y    = buttons.center.y + 35
    label_text = state.play ? "Pause Animation" : "Play Animation"
    outputs.labels << [label_x, label_y, label_text]
  end

  def render_right_button
    # Draws the button_color button, and a black border
    # The border separates the buttons visually
    outputs.solids  << [buttons.right, button_color]
    outputs.borders << [buttons.right]

    # Renders an explanatory label in the center of the button
    # Explains to the user what the button does
    label_x = buttons.right.x + 20
    label_y = buttons.right.y + 35
    outputs.labels  << [label_x, label_y, ">"]
  end

  def render_bfs_grid
    # A large rect the size of the grid
    outputs.solids << bfs_scale_up(grid.rect).merge(default_color)

    outputs.lines << (0..grid.width).map { |x| bfs_vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| bfs_horizontal_line(y) }
  end

  def render_heuristic_grid
    # A large rect the size of the grid
    outputs.solids << heuristic_scale_up(grid.rect).merge(default_color)

    outputs.lines << (0..grid.width).map { |x| heuristic_vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| heuristic_horizontal_line(y) }
  end

  # Returns a vertical line for a column of the first grid
  def bfs_vertical_line x
    line = { x: x, y: 0, w: 0, h: grid.height }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Returns a horizontal line for a column of the first grid
  def bfs_horizontal_line y
    line = { x: 0, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Returns a vertical line for a column of the second grid
  def heuristic_vertical_line x
    bfs_vertical_line(x + grid.width + 1)
  end

  # Returns a horizontal line for a column of the second grid
  def heuristic_horizontal_line y
    line = { x: grid.width + 1, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Renders the star on the first grid
  def render_bfs_star
    outputs.sprites << bfs_scale_up(grid.star).merge({ path: 'star.png' })
  end

  # Renders the star on the second grid
  def render_heuristic_star
    outputs.sprites << heuristic_scale_up(grid.star).merge({ path: 'star.png' })
  end

  # Renders the target on the first grid
  def render_bfs_target
    outputs.sprites << bfs_scale_up(grid.target).merge({ path: 'target.png' })
  end

  # Renders the target on the second grid
  def render_heuristic_target
    outputs.sprites << heuristic_scale_up(grid.target).merge({ path: 'target.png' })
  end

  # Renders the walls on the first grid
  def render_bfs_walls
    outputs.solids << grid.walls.map do |key, value|
      bfs_scale_up(key).merge(wall_color)
    end
  end

  # Renders the walls on the second grid
  def render_heuristic_walls
    outputs.solids << grid.walls.map do |key, value|
      heuristic_scale_up(key).merge(wall_color)
    end
  end

  # Renders the visited cells on the first grid
  def render_bfs_visited
    outputs.solids << bfs.came_from.map do |key, value|
      bfs_scale_up(key).merge(visited_color)
    end
  end

  # Renders the visited cells on the second grid
  def render_heuristic_visited
    outputs.solids << heuristic.came_from.map do |key, value|
      heuristic_scale_up(key).merge(visited_color)
    end
  end

  # Renders the frontier cells on the first grid
  def render_bfs_frontier
    outputs.solids << bfs.frontier.map do |cell|
      bfs_scale_up(cell).merge(frontier_color)
    end
  end

  # Renders the frontier cells on the second grid
  def render_heuristic_frontier
    outputs.solids << heuristic.frontier.map do |cell|
      heuristic_scale_up(cell).merge(frontier_color)
    end
  end

  # Renders the path found by the breadth first search on the first grid
  def render_bfs_path
    outputs.solids << bfs.path.map do |path|
      bfs_scale_up(path).merge(path_color)
    end
  end

  # Renders the path found by the heuristic search on the second grid
  def render_heuristic_path
    outputs.solids << heuristic.path.map do |path|
      heuristic_scale_up(path).merge(path_color)
    end
  end

  # Returns the rect for the path between two cells based on their relative positions
  def get_path_between(cell_one, cell_two)
    path = nil

    # If cell one is above cell two
    if cell_one.x == cell_two.x && cell_one.y > cell_two.y
      # Path starts from the center of cell two and moves upward to the center of cell one
      path = [cell_two.x + 0.3, cell_two.y + 0.3, 0.4, 1.4]
    # If cell one is below cell two
    elsif cell_one.x == cell_two.x && cell_one.y < cell_two.y
      # Path starts from the center of cell one and moves upward to the center of cell two
      path = [cell_one.x + 0.3, cell_one.y + 0.3, 0.4, 1.4]
    # If cell one is to the left of cell two
    elsif cell_one.x > cell_two.x && cell_one.y == cell_two.y
      # Path starts from the center of cell two and moves rightward to the center of cell one
      path = [cell_two.x + 0.3, cell_two.y + 0.3, 1.4, 0.4]
    # If cell one is to the right of cell two
    elsif cell_one.x < cell_two.x && cell_one.y == cell_two.y
      # Path starts from the center of cell one and moves rightward to the center of cell two
      path = [cell_one.x + 0.3, cell_one.y + 0.3, 1.4, 0.4]
    end

    path
  end

  # In code, the cells are represented as 1x1 rectangles
  # When drawn, the cells are larger than 1x1 rectangles
  # This method is used to scale up cells, and lines
  # Objects are scaled up according to the grid.cell_size variable
  # This allows for easy customization of the visual scale of the grid
  # This method scales up cells for the first grid
  def bfs_scale_up(cell)
    x = cell.x * grid.cell_size
    y = cell.y * grid.cell_size
    w = cell.w.zero? ? grid.cell_size : cell.w * grid.cell_size
    h = cell.h.zero? ? grid.cell_size : cell.h * grid.cell_size
    {x: x, y: y, w: w, h: h}
    # {x:, y:, w:, h:}
  end

  # Translates the given cell grid.width + 1 to the right and then scales up
  # Used to draw cells for the second grid
  # This method does not work for lines,
  # so separate methods exist for the grid lines
  def heuristic_scale_up(cell)
    # Prevents the original value of cell from being edited
    cell = cell.clone
    # Translates the cell to the second grid equivalent
    cell.x += grid.width + 1
    # Proceeds as if scaling up for the first grid
    bfs_scale_up(cell)
  end

  # Checks and handles input for the buttons
  # Called when the mouse is lifted
  def input_buttons
    input_left_button
    input_center_button
    input_right_button
  end

  # Checks if the previous step button is clicked
  # If it is, it pauses the animation and moves the search one step backward
  def input_left_button
    if left_button_clicked?
      state.play = false
      state.current_step -= 1
      recalculate_searches
    end
  end

  # Controls the play/pause button
  # Inverses whether the animation is playing or not when clicked
  def input_center_button
    if center_button_clicked? || inputs.keyboard.key_down.space
      state.play = !state.play
    end
  end

  # Checks if the next step button is clicked
  # If it is, it pauses the animation and moves the search one step forward
  def input_right_button
    if right_button_clicked?
      state.play = false
      state.current_step += 1
      move_searches_one_step_forward
    end
  end

  # These methods detect when the buttons are clicked
  def left_button_clicked?
    inputs.mouse.point.inside_rect?(buttons.left) && inputs.mouse.up
  end

  def center_button_clicked?
    inputs.mouse.point.inside_rect?(buttons.center) && inputs.mouse.up
  end

  def right_button_clicked?
    inputs.mouse.point.inside_rect?(buttons.right) && inputs.mouse.up
  end


  # Signal that the user is going to be moving the slider
  # Is the mouse over the circle of the slider?
  def mouse_over_slider?
    circle_x = (slider.x - slider.offset) + (state.current_step * slider.spacing)
    circle_y = (slider.y - slider.offset)
    circle_rect = [circle_x, circle_y, 37, 37]
    inputs.mouse.point.inside_rect?(circle_rect)
  end

  # Signal that the user is going to be moving the star from the first grid
  def bfs_mouse_over_star?
    inputs.mouse.point.inside_rect?(bfs_scale_up(grid.star))
  end

  # Signal that the user is going to be moving the star from the second grid
  def heuristic_mouse_over_star?
    inputs.mouse.point.inside_rect?(heuristic_scale_up(grid.star))
  end

  # Signal that the user is going to be moving the target from the first grid
  def bfs_mouse_over_target?
    inputs.mouse.point.inside_rect?(bfs_scale_up(grid.target))
  end

  # Signal that the user is going to be moving the target from the second grid
  def heuristic_mouse_over_target?
    inputs.mouse.point.inside_rect?(heuristic_scale_up(grid.target))
  end

  # Signal that the user is going to be removing walls from the first grid
  def bfs_mouse_over_wall?
    grid.walls.each_key do |wall|
      return true if inputs.mouse.point.inside_rect?(bfs_scale_up(wall))
    end

    false
  end

  # Signal that the user is going to be removing walls from the second grid
  def heuristic_mouse_over_wall?
    grid.walls.each_key do |wall|
      return true if inputs.mouse.point.inside_rect?(heuristic_scale_up(wall))
    end

    false
  end

  # Signal that the user is going to be adding walls from the first grid
  def bfs_mouse_over_grid?
    inputs.mouse.point.inside_rect?(bfs_scale_up(grid.rect))
  end

  # Signal that the user is going to be adding walls from the second grid
  def heuristic_mouse_over_grid?
    inputs.mouse.point.inside_rect?(heuristic_scale_up(grid.rect))
  end

  # This method is called when the user is editing the slider
  # It pauses the animation and moves the white circle to the closest integer point
  # on the slider
  # Changes the step of the search to be animated
  def process_input_slider
    state.play = false
    mouse_x = inputs.mouse.point.x

    # Bounds the mouse_x to the closest x value on the slider line
    mouse_x = slider.x if mouse_x < slider.x
    mouse_x = slider.x + slider.w if mouse_x > slider.x + slider.w

    # Sets the current search step to the one represented by the mouse x value
    # The slider's circle moves due to the render_slider method using anim_steps
    state.current_step = ((mouse_x - slider.x) / slider.spacing).to_i

    recalculate_searches
  end

  # Moves the star to the cell closest to the mouse in the first grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def process_input_bfs_star
    old_star = grid.star.clone
    unless bfs_cell_closest_to_mouse == grid.target
      grid.star = bfs_cell_closest_to_mouse
    end
    unless old_star == grid.star
      recalculate_searches
    end
  end

  # Moves the star to the cell closest to the mouse in the second grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def process_input_heuristic_star
    old_star = grid.star.clone
    unless heuristic_cell_closest_to_mouse == grid.target
      grid.star = heuristic_cell_closest_to_mouse
    end
    unless old_star == grid.star
      recalculate_searches
    end
  end

  # Moves the target to the grid closest to the mouse in the first grid
  # Only recalculate_searchess the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def process_input_bfs_target
    old_target = grid.target.clone
    unless bfs_cell_closest_to_mouse == grid.star
      grid.target = bfs_cell_closest_to_mouse
    end
    unless old_target == grid.target
      recalculate_searches
    end
  end

  # Moves the target to the cell closest to the mouse in the second grid
  # Only recalculate_searchess the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def process_input_heuristic_target
    old_target = grid.target.clone
    unless heuristic_cell_closest_to_mouse == grid.star
      grid.target = heuristic_cell_closest_to_mouse
    end
    unless old_target == grid.target
      recalculate_searches
    end
  end

  # Removes walls in the first grid that are under the cursor
  def process_input_bfs_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if bfs_mouse_over_grid?
      if grid.walls.key?(bfs_cell_closest_to_mouse)
        grid.walls.delete(bfs_cell_closest_to_mouse)
        recalculate_searches
      end
    end
  end

  # Removes walls in the second grid that are under the cursor
  def process_input_heuristic_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if heuristic_mouse_over_grid?
      if grid.walls.key?(heuristic_cell_closest_to_mouse)
        grid.walls.delete(heuristic_cell_closest_to_mouse)
        recalculate_searches
      end
    end
  end
  # Adds a wall in the first grid in the cell the mouse is over
  def process_input_bfs_add_wall
    if bfs_mouse_over_grid?
      unless grid.walls.key?(bfs_cell_closest_to_mouse)
        grid.walls[bfs_cell_closest_to_mouse] = true
        recalculate_searches
      end
    end
  end

  # Adds a wall in the second grid in the cell the mouse is over
  def process_input_heuristic_add_wall
    if heuristic_mouse_over_grid?
      unless grid.walls.key?(heuristic_cell_closest_to_mouse)
        grid.walls[heuristic_cell_closest_to_mouse] = true
        recalculate_searches
      end
    end
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse helps with this
  def bfs_cell_closest_to_mouse
    # Closest cell to the mouse in the first grid
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Bound x and y to the grid
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse in the second grid helps with this
  def heuristic_cell_closest_to_mouse
    # Closest cell grid to the mouse in the second
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Translate the cell to the first grid
    x -= grid.width + 1
    # Bound x and y to the first grid
    x = 0 if x < 0
    y = 0 if y < 0
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  def recalculate_searches
    # Reset the searches
    bfs.came_from    = {}
    bfs.frontier     = []
    bfs.path         = []
    heuristic.came_from = {}
    heuristic.frontier  = []
    heuristic.path      = []

    # Move the searches forward to the current step
    state.current_step.times { move_searches_one_step_forward }
  end

  def move_searches_one_step_forward
    bfs_one_step_forward
    heuristic_one_step_forward
  end

  def bfs_one_step_forward
    return if bfs.came_from.key?(grid.target)

    # Only runs at the beginning of the search as setup.
    if bfs.came_from.empty?
      bfs.frontier << grid.star
      bfs.came_from[grid.star] = nil
    end

    # A step in the search
    unless bfs.frontier.empty?
      # Takes the next frontier cell
      new_frontier = bfs.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do |neighbor|
        # That have not been visited and are not walls
        unless bfs.came_from.key?(neighbor) || grid.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited
          bfs.frontier << neighbor
          bfs.came_from[neighbor] = new_frontier
        end
      end
    end

    # Sort the frontier so that cells that are in a zigzag pattern are prioritized over those in an line
    # Comment this line and let a path generate to see the difference
    bfs.frontier = bfs.frontier.sort_by { |cell| proximity_to_star(cell) }

    # If the search found the target
    if bfs.came_from.key?(grid.target)
      # Calculate the path between the target and star
      bfs_calc_path
    end
  end

  # Calculates the path between the target and star for the breadth first search
  # Only called when the breadth first search finds the target
  def bfs_calc_path
    # Start from the target
    endpoint = grid.target
    # And the cell it came from
    next_endpoint = bfs.came_from[endpoint]
    while endpoint && next_endpoint
      # Draw a path between these two cells and store it
      path = get_path_between(endpoint, next_endpoint)
      bfs.path << path
      # And get the next pair of cells
      endpoint = next_endpoint
      next_endpoint = bfs.came_from[endpoint]
      # Continue till there are no more cells
    end
  end

  # Moves the heuristic search forward one step
  # Can be called from tick while the animation is playing
  # Can also be called when recalculating the searches after the user edited the grid
  def heuristic_one_step_forward
    # Stop the search if the target has been found
    return if heuristic.came_from.key?(grid.target)

    # If the search has not begun
    if heuristic.came_from.empty?
      # Setup the search to begin from the star
      heuristic.frontier << grid.star
      heuristic.came_from[grid.star] = nil
    end

    # One step in the heuristic search

    # Unless there are no more cells to explore from
    unless heuristic.frontier.empty?
      # Get the next cell to explore from
      new_frontier = heuristic.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do |neighbor|
        # That have not been visited and are not walls
        unless heuristic.came_from.key?(neighbor) || grid.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited
          heuristic.frontier << neighbor
          heuristic.came_from[neighbor] = new_frontier
        end
      end
    end

    # Sort the frontier so that cells that are in a zigzag pattern are prioritized over those in an line
    heuristic.frontier = heuristic.frontier.sort_by { |cell| proximity_to_star(cell) }
    # Sort the frontier so cells that are close to the target are then prioritized
    heuristic.frontier = heuristic.frontier.sort_by { |cell| heuristic_heuristic(cell) }

    # If the search found the target
    if heuristic.came_from.key?(grid.target)
      # Calculate the path between the target and star
      heuristic_calc_path
    end
  end

  # Returns one-dimensional absolute distance between cell and target
  # Returns a number to compare distances between cells and the target
  def heuristic_heuristic(cell)
    (grid.target.x - cell.x).abs + (grid.target.y - cell.y).abs
  end

  # Calculates the path between the target and star for the heuristic search
  # Only called when the heuristic search finds the target
  def heuristic_calc_path
    # Start from the target
    endpoint = grid.target
    # And the cell it came from
    next_endpoint = heuristic.came_from[endpoint]
    while endpoint && next_endpoint
      # Draw a path between these two cells and store it
      path = get_path_between(endpoint, next_endpoint)
      heuristic.path << path
      # And get the next pair of cells
      endpoint = next_endpoint
      next_endpoint = heuristic.came_from[endpoint]
      # Continue till there are no more cells
    end
  end

  # Returns a list of adjacent cells
  # Used to determine what the next cells to be added to the frontier are
  def adjacent_neighbors(cell)
    neighbors = []

    # Gets all the valid neighbors into the array
    # From southern neighbor, clockwise
    neighbors << [cell.x    , cell.y - 1] unless cell.y == 0
    neighbors << [cell.x - 1, cell.y    ] unless cell.x == 0
    neighbors << [cell.x    , cell.y + 1] unless cell.y == grid.height - 1
    neighbors << [cell.x + 1, cell.y    ] unless cell.x == grid.width - 1

    neighbors
  end

  # Finds the vertical and horizontal distance of a cell from the star
  # and returns the larger value
  # This method is used to have a zigzag pattern in the rendered path
  # A cell that is [5, 5] from the star,
  # is explored before over a cell that is [0, 7] away.
  # So, if possible, the search tries to go diagonal (zigzag) first
  def proximity_to_star(cell)
    distance_x = (grid.star.x - cell.x).abs
    distance_y = (grid.star.y - cell.y).abs

    [distance_x, distance_y].max
  end

  # Methods that allow code to be more concise. Subdivides args.state, which is where all variables are stored.
  def grid
    state.grid
  end

  def buttons
    state.buttons
  end

  def slider
    state.slider
  end

  def bfs
    state.bfs
  end

  def heuristic
    state.heuristic
  end

  # Descriptive aliases for colors
  def default_color
    { r: 221, g: 212, b: 213 }
  end

  def wall_color
    { r: 134, g: 134, b: 120 }
  end

  def visited_color
    { r: 204, g: 191, b: 179 }
  end

  def frontier_color
    { r: 103, g: 136, b: 204, a: 200 }
  end

  def path_color
    { r: 231, g: 230, b: 228 }
  end

  def button_color
    [190, 190, 190] # Gray
  end
end
# Method that is called by DragonRuby periodically
# Used for updating animations and calculations
def tick args

  # Pressing r will reset the application
  if args.inputs.keyboard.key_down.r
    args.gtk.reset
    reset
    return
  end

  # Every tick, new args are passed, and the Breadth First Search tick is called
  $heuristic_with_walls ||= Heuristic_With_Walls.new
  $heuristic_with_walls.args = args
  $heuristic_with_walls.tick
end


def reset
  $heuristic_with_walls = nil
end

A Star - main.rb link

# ./samples/13_path_finding_algorithms/08_a_star/app/main.rb
# Contributors outside of DragonRuby who also hold Copyright:
# - Sujay Vadlakonda: https://github.com/sujayvadlakonda

# This program is inspired by https://www.redblobgames.com/pathfinding/a-star/introduction.html

# The A* Search works by incorporating both the distance from the starting point
# and the distance from the target in its heurisitic.

# It tends to find the correct (shortest) path even when the Greedy Best-First Search does not,
# and it explores less of the grid, and is therefore faster, than Dijkstra's Search.

class A_Star_Algorithm
  attr_gtk

  def tick
    defaults
    render
    input

    if dijkstra.came_from.empty?
      calc_searches
    end
  end

  def defaults
    # Variables to edit the size and appearance of the grid
    # Freely customizable to user's liking
    grid.width     ||= 15
    grid.height    ||= 15
    grid.cell_size ||= 27
    grid.rect      ||= [0, 0, grid.width, grid.height]

    grid.star      ||= [0, 2]
    grid.target    ||= [11, 13]
    grid.walls     ||= {
      [2, 2] => true,
      [3, 2] => true,
      [4, 2] => true,
      [5, 2] => true,
      [6, 2] => true,
      [7, 2] => true,
      [8, 2] => true,
      [9, 2] => true,
      [10, 2] => true,
      [11, 2] => true,
      [12, 2] => true,
      [12, 3] => true,
      [12, 4] => true,
      [12, 5] => true,
      [12, 6] => true,
      [12, 7] => true,
      [12, 8] => true,
      [12, 9] => true,
      [12, 10] => true,
      [12, 11] => true,
      [12, 12] => true,
      [5, 12] => true,
      [6, 12] => true,
      [7, 12] => true,
      [8, 12] => true,
      [9, 12] => true,
      [10, 12] => true,
      [11, 12] => true,
      [12, 12] => true
    }

    # What the user is currently editing on the grid
    # We store this value, because we want to remember the value even when
    # the user's cursor is no longer over what they're interacting with, but
    # they are still clicking down on the mouse.
    state.user_input ||= :none

    # These variables allow the breadth first search to take place
    # Came_from is a hash with a key of a cell and a value of the cell that was expanded from to find the key.
    # Used to prevent searching cells that have already been found
    # and to trace a path from the target back to the starting point.
    # Frontier is an array of cells to expand the search from.
    # The search is over when there are no more cells to search from.
    # Path stores the path from the target to the star, once the target has been found
    # It prevents calculating the path every tick.
    dijkstra.came_from   ||= {}
    dijkstra.cost_so_far ||= {}
    dijkstra.frontier    ||= []
    dijkstra.path        ||= []

    greedy.came_from ||= {}
    greedy.frontier  ||= []
    greedy.path      ||= []

    a_star.frontier    ||= []
    a_star.came_from   ||= {}
    a_star.path        ||= []
    a_star.cost_so_far ||= {}
  end

  # All methods with render draw stuff on the screen
  # UI has buttons, the slider, and labels
  # The search specific rendering occurs in the respective methods
  def render
    render_labels
    render_dijkstra
    render_greedy
    render_a_star
  end

  def render_labels
    outputs.labels << [150, 450, "Dijkstra's"]
    outputs.labels << [550, 450, "Greedy Best-First"]
    outputs.labels << [1025, 450, "A* Search"]
  end

  def render_dijkstra
    render_dijkstra_grid
    render_dijkstra_star
    render_dijkstra_target
    render_dijkstra_visited
    render_dijkstra_walls
    render_dijkstra_path
  end

  def render_greedy
    render_greedy_grid
    render_greedy_star
    render_greedy_target
    render_greedy_visited
    render_greedy_walls
    render_greedy_path
  end

  def render_a_star
    render_a_star_grid
    render_a_star_star
    render_a_star_target
    render_a_star_visited
    render_a_star_walls
    render_a_star_path
  end

  # This method handles user input every tick
  def input
    # If the mouse was lifted this tick
    if inputs.mouse.up
      # Set current input to none
      state.user_input = :none
    end

    # If the mouse was clicked this tick
    if inputs.mouse.down
      # Determine what the user is editing and appropriately edit the state.user_input variable
      determine_input
    end

    # Process user input based on user_input variable and current mouse position
    process_input
  end

  # Determines what the user is editing
  # This method is called when the mouse is clicked down
  def determine_input
    # If the mouse is over the star in the first grid
    if dijkstra_mouse_over_star?
      # The user is editing the star from the first grid
      state.user_input = :dijkstra_star
    # If the mouse is over the star in the second grid
    elsif greedy_mouse_over_star?
      # The user is editing the star from the second grid
      state.user_input = :greedy_star
    # If the mouse is over the star in the third grid
    elsif a_star_mouse_over_star?
      # The user is editing the star from the third grid
      state.user_input = :a_star_star
    # If the mouse is over the target in the first grid
    elsif dijkstra_mouse_over_target?
      # The user is editing the target from the first grid
      state.user_input = :dijkstra_target
    # If the mouse is over the target in the second grid
    elsif greedy_mouse_over_target?
      # The user is editing the target from the second grid
      state.user_input = :greedy_target
    # If the mouse is over the target in the third grid
    elsif a_star_mouse_over_target?
      # The user is editing the target from the third grid
      state.user_input = :a_star_target
    # If the mouse is over a wall in the first grid
    elsif dijkstra_mouse_over_wall?
      # The user is removing a wall from the first grid
      state.user_input = :dijkstra_remove_wall
    # If the mouse is over a wall in the second grid
    elsif greedy_mouse_over_wall?
      # The user is removing a wall from the second grid
      state.user_input = :greedy_remove_wall
    # If the mouse is over a wall in the third grid
    elsif a_star_mouse_over_wall?
      # The user is removing a wall from the third grid
      state.user_input = :a_star_remove_wall
    # If the mouse is over the first grid
    elsif dijkstra_mouse_over_grid?
      # The user is adding a wall from the first grid
      state.user_input = :dijkstra_add_wall
    # If the mouse is over the second grid
    elsif greedy_mouse_over_grid?
      # The user is adding a wall from the second grid
      state.user_input = :greedy_add_wall
    # If the mouse is over the third grid
    elsif a_star_mouse_over_grid?
      # The user is adding a wall from the third grid
      state.user_input = :a_star_add_wall
    end
  end

  # Processes click and drag based on what the user is currently dragging
  def process_input
    if state.user_input == :dijkstra_star
      process_input_dijkstra_star
    elsif state.user_input == :greedy_star
      process_input_greedy_star
    elsif state.user_input == :a_star_star
      process_input_a_star_star
    elsif state.user_input == :dijkstra_target
      process_input_dijkstra_target
    elsif state.user_input == :greedy_target
      process_input_greedy_target
    elsif state.user_input == :a_star_target
      process_input_a_star_target
    elsif state.user_input == :dijkstra_remove_wall
      process_input_dijkstra_remove_wall
    elsif state.user_input == :greedy_remove_wall
      process_input_greedy_remove_wall
    elsif state.user_input == :a_star_remove_wall
      process_input_a_star_remove_wall
    elsif state.user_input == :dijkstra_add_wall
      process_input_dijkstra_add_wall
    elsif state.user_input == :greedy_add_wall
      process_input_greedy_add_wall
    elsif state.user_input == :a_star_add_wall
      process_input_a_star_add_wall
    end
  end

  def render_dijkstra_grid
    # A large rect the size of the grid
    outputs.solids << dijkstra_scale_up(grid.rect).merge(default_color)

    outputs.lines << (0..grid.width).map { |x| dijkstra_vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| dijkstra_horizontal_line(y) }
  end

  def render_greedy_grid
    # A large rect the size of the grid
    outputs.solids << greedy_scale_up(grid.rect).merge(default_color)

    outputs.lines << (0..grid.width).map { |x| greedy_vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| greedy_horizontal_line(y) }
  end

  def render_a_star_grid
    # A large rect the size of the grid
    outputs.solids << a_star_scale_up(grid.rect).merge(default_color)

    outputs.lines << (0..grid.width).map { |x| a_star_vertical_line(x) }
    outputs.lines << (0..grid.height).map { |y| a_star_horizontal_line(y) }
  end

  # Returns a vertical line for a column of the first grid
  def dijkstra_vertical_line x
    line = { x: x, y: 0, w: 0, h: grid.height }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Returns a horizontal line for a column of the first grid
  def dijkstra_horizontal_line y
    line = { x: 0, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Returns a vertical line for a column of the second grid
  def greedy_vertical_line x
    dijkstra_vertical_line(x + grid.width + 1)
  end

  # Returns a horizontal line for a column of the second grid
  def greedy_horizontal_line y
    line = { x: grid.width + 1, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Returns a vertical line for a column of the third grid
  def a_star_vertical_line x
    dijkstra_vertical_line(x + grid.width + 1 + grid.width + 1)
  end

  # Returns a horizontal line for a column of the third grid
  def a_star_horizontal_line y
    line = { x: grid.width + 1 + grid.width + 1, y: y, w: grid.width, h: 0 }
    line.transform_values { |v| v * grid.cell_size }
  end

  # Renders the star on the first grid
  def render_dijkstra_star
    outputs.sprites << dijkstra_scale_up(grid.star).merge({ path: 'star.png' })
  end

  # Renders the star on the second grid
  def render_greedy_star
    outputs.sprites << greedy_scale_up(grid.star).merge({ path: 'star.png' })
  end

  # Renders the star on the third grid
  def render_a_star_star
    outputs.sprites << a_star_scale_up(grid.star).merge({ path: 'star.png' })
  end

  # Renders the target on the first grid
  def render_dijkstra_target
    outputs.sprites << dijkstra_scale_up(grid.target).merge({ path: 'target.png' })
  end

  # Renders the target on the second grid
  def render_greedy_target
    outputs.sprites << greedy_scale_up(grid.target).merge({ path: 'target.png' })
  end

  # Renders the target on the third grid
  def render_a_star_target
    outputs.sprites << a_star_scale_up(grid.target).merge({ path: 'target.png' })
  end

  # Renders the walls on the first grid
  def render_dijkstra_walls
    outputs.solids << grid.walls.map do |key, value|
      dijkstra_scale_up(key).merge(wall_color)
    end
  end

  # Renders the walls on the second grid
  def render_greedy_walls
    outputs.solids << grid.walls.map do |key, value|
      greedy_scale_up(key).merge(wall_color)
    end
  end

  # Renders the walls on the third grid
  def render_a_star_walls
    outputs.solids << grid.walls.map do |key, value|
      a_star_scale_up(key).merge(wall_color)
    end
  end

  # Renders the visited cells on the first grid
  def render_dijkstra_visited
    outputs.solids << dijkstra.came_from.map do |key, value|
      dijkstra_scale_up(key).merge(visited_color)
    end
  end

  # Renders the visited cells on the second grid
  def render_greedy_visited
    outputs.solids << greedy.came_from.map do |key, value|
      greedy_scale_up(key).merge(visited_color)
    end
  end

  # Renders the visited cells on the third grid
  def render_a_star_visited
    outputs.solids << a_star.came_from.map do |key, value|
      a_star_scale_up(key).merge(visited_color)
    end
  end

  # Renders the path found by the breadth first search on the first grid
  def render_dijkstra_path
    outputs.solids << dijkstra.path.map do |path|
      dijkstra_scale_up(path).merge(path_color)
    end
  end

  # Renders the path found by the greedy search on the second grid
  def render_greedy_path
    outputs.solids << greedy.path.map do |path|
      greedy_scale_up(path).merge(path_color)
    end
  end

  # Renders the path found by the a_star search on the third grid
  def render_a_star_path
    outputs.solids << a_star.path.map do |path|
      a_star_scale_up(path).merge(path_color)
    end
  end

  # Returns the rect for the path between two cells based on their relative positions
  def get_path_between(cell_one, cell_two)
    path = []

    # If cell one is above cell two
    if cell_one.x == cell_two.x && cell_one.y > cell_two.y
      # Path starts from the center of cell two and moves upward to the center of cell one
      path = [cell_two.x + 0.3, cell_two.y + 0.3, 0.4, 1.4]
    # If cell one is below cell two
    elsif cell_one.x == cell_two.x && cell_one.y < cell_two.y
      # Path starts from the center of cell one and moves upward to the center of cell two
      path = [cell_one.x + 0.3, cell_one.y + 0.3, 0.4, 1.4]
    # If cell one is to the left of cell two
    elsif cell_one.x > cell_two.x && cell_one.y == cell_two.y
      # Path starts from the center of cell two and moves rightward to the center of cell one
      path = [cell_two.x + 0.3, cell_two.y + 0.3, 1.4, 0.4]
    # If cell one is to the right of cell two
    elsif cell_one.x < cell_two.x && cell_one.y == cell_two.y
      # Path starts from the center of cell one and moves rightward to the center of cell two
      path = [cell_one.x + 0.3, cell_one.y + 0.3, 1.4, 0.4]
    end

    path
  end

  # In code, the cells are represented as 1x1 rectangles
  # When drawn, the cells are larger than 1x1 rectangles
  # This method is used to scale up cells, and lines
  # Objects are scaled up according to the grid.cell_size variable
  # This allows for easy customization of the visual scale of the grid
  # This method scales up cells for the first grid
  def dijkstra_scale_up(cell)
    x = cell.x * grid.cell_size
    y = cell.y * grid.cell_size
    w = cell.w.zero? ? grid.cell_size : cell.w * grid.cell_size
    h = cell.h.zero? ? grid.cell_size : cell.h * grid.cell_size
    {x: x, y: y, w: w, h: h}
  end

  # Translates the given cell grid.width + 1 to the right and then scales up
  # Used to draw cells for the second grid
  # This method does not work for lines,
  # so separate methods exist for the grid lines
  def greedy_scale_up(cell)
    # Prevents the original value of cell from being edited
    cell = cell.clone
    # Translates the cell to the second grid equivalent
    cell.x += grid.width + 1
    # Proceeds as if scaling up for the first grid
    dijkstra_scale_up(cell)
  end

  # Translates the given cell (grid.width + 1) * 2 to the right and then scales up
  # Used to draw cells for the third grid
  # This method does not work for lines,
  # so separate methods exist for the grid lines
  def a_star_scale_up(cell)
    # Prevents the original value of cell from being edited
    cell = cell.clone
    # Translates the cell to the second grid equivalent
    cell.x += grid.width + 1
    # Translates the cell to the third grid equivalent
    cell.x += grid.width + 1
    # Proceeds as if scaling up for the first grid
    dijkstra_scale_up(cell)
  end

  # Signal that the user is going to be moving the star from the first grid
  def dijkstra_mouse_over_star?
    inputs.mouse.point.inside_rect?(dijkstra_scale_up(grid.star))
  end

  # Signal that the user is going to be moving the star from the second grid
  def greedy_mouse_over_star?
    inputs.mouse.point.inside_rect?(greedy_scale_up(grid.star))
  end

  # Signal that the user is going to be moving the star from the third grid
  def a_star_mouse_over_star?
    inputs.mouse.point.inside_rect?(a_star_scale_up(grid.star))
  end

  # Signal that the user is going to be moving the target from the first grid
  def dijkstra_mouse_over_target?
    inputs.mouse.point.inside_rect?(dijkstra_scale_up(grid.target))
  end

  # Signal that the user is going to be moving the target from the second grid
  def greedy_mouse_over_target?
    inputs.mouse.point.inside_rect?(greedy_scale_up(grid.target))
  end

  # Signal that the user is going to be moving the target from the third grid
  def a_star_mouse_over_target?
    inputs.mouse.point.inside_rect?(a_star_scale_up(grid.target))
  end

  # Signal that the user is going to be removing walls from the first grid
  def dijkstra_mouse_over_wall?
    grid.walls.each_key do | wall |
      return true if inputs.mouse.point.inside_rect?(dijkstra_scale_up(wall))
    end

    false
  end

  # Signal that the user is going to be removing walls from the second grid
  def greedy_mouse_over_wall?
    grid.walls.each_key do | wall |
      return true if inputs.mouse.point.inside_rect?(greedy_scale_up(wall))
    end

    false
  end

  # Signal that the user is going to be removing walls from the third grid
  def a_star_mouse_over_wall?
    grid.walls.each_key do | wall |
      return true if inputs.mouse.point.inside_rect?(a_star_scale_up(wall))
    end

    false
  end

  # Signal that the user is going to be adding walls from the first grid
  def dijkstra_mouse_over_grid?
    inputs.mouse.point.inside_rect?(dijkstra_scale_up(grid.rect))
  end

  # Signal that the user is going to be adding walls from the second grid
  def greedy_mouse_over_grid?
    inputs.mouse.point.inside_rect?(greedy_scale_up(grid.rect))
  end

  # Signal that the user is going to be adding walls from the third grid
  def a_star_mouse_over_grid?
    inputs.mouse.point.inside_rect?(a_star_scale_up(grid.rect))
  end

  # Moves the star to the cell closest to the mouse in the first grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def process_input_dijkstra_star
    old_star = grid.star.clone
    unless dijkstra_cell_closest_to_mouse == grid.target
      grid.star = dijkstra_cell_closest_to_mouse
    end
    unless old_star == grid.star
      reset_searches
    end
  end

  # Moves the star to the cell closest to the mouse in the second grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def process_input_greedy_star
    old_star = grid.star.clone
    unless greedy_cell_closest_to_mouse == grid.target
      grid.star = greedy_cell_closest_to_mouse
    end
    unless old_star == grid.star
      reset_searches
    end
  end

  # Moves the star to the cell closest to the mouse in the third grid
  # Only resets the search if the star changes position
  # Called whenever the user is editing the star (puts mouse down on star)
  def process_input_a_star_star
    old_star = grid.star.clone
    unless a_star_cell_closest_to_mouse == grid.target
      grid.star = a_star_cell_closest_to_mouse
    end
    unless old_star == grid.star
      reset_searches
    end
  end

  # Moves the target to the grid closest to the mouse in the first grid
  # Only reset_searchess the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def process_input_dijkstra_target
    old_target = grid.target.clone
    unless dijkstra_cell_closest_to_mouse == grid.star
      grid.target = dijkstra_cell_closest_to_mouse
    end
    unless old_target == grid.target
      reset_searches
    end
  end

  # Moves the target to the cell closest to the mouse in the second grid
  # Only reset_searchess the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def process_input_greedy_target
    old_target = grid.target.clone
    unless greedy_cell_closest_to_mouse == grid.star
      grid.target = greedy_cell_closest_to_mouse
    end
    unless old_target == grid.target
      reset_searches
    end
  end

  # Moves the target to the cell closest to the mouse in the third grid
  # Only reset_searchess the search if the target changes position
  # Called whenever the user is editing the target (puts mouse down on target)
  def process_input_a_star_target
    old_target = grid.target.clone
    unless a_star_cell_closest_to_mouse == grid.star
      grid.target = a_star_cell_closest_to_mouse
    end
    unless old_target == grid.target
      reset_searches
    end
  end

  # Removes walls in the first grid that are under the cursor
  def process_input_dijkstra_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if dijkstra_mouse_over_grid?
      if grid.walls.has_key?(dijkstra_cell_closest_to_mouse)
        grid.walls.delete(dijkstra_cell_closest_to_mouse)
        reset_searches
      end
    end
  end

  # Removes walls in the second grid that are under the cursor
  def process_input_greedy_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if greedy_mouse_over_grid?
      if grid.walls.key?(greedy_cell_closest_to_mouse)
        grid.walls.delete(greedy_cell_closest_to_mouse)
        reset_searches
      end
    end
  end

  # Removes walls in the third grid that are under the cursor
  def process_input_a_star_remove_wall
    # The mouse needs to be inside the grid, because we only want to remove walls
    # the cursor is directly over
    # Recalculations should only occur when a wall is actually deleted
    if a_star_mouse_over_grid?
      if grid.walls.key?(a_star_cell_closest_to_mouse)
        grid.walls.delete(a_star_cell_closest_to_mouse)
        reset_searches
      end
    end
  end

  # Adds a wall in the first grid in the cell the mouse is over
  def process_input_dijkstra_add_wall
    if dijkstra_mouse_over_grid?
      unless grid.walls.key?(dijkstra_cell_closest_to_mouse)
        grid.walls[dijkstra_cell_closest_to_mouse] = true
        reset_searches
      end
    end
  end

  # Adds a wall in the second grid in the cell the mouse is over
  def process_input_greedy_add_wall
    if greedy_mouse_over_grid?
      unless grid.walls.key?(greedy_cell_closest_to_mouse)
        grid.walls[greedy_cell_closest_to_mouse] = true
        reset_searches
      end
    end
  end

  # Adds a wall in the third grid in the cell the mouse is over
  def process_input_a_star_add_wall
    if a_star_mouse_over_grid?
      unless grid.walls.key?(a_star_cell_closest_to_mouse)
        grid.walls[a_star_cell_closest_to_mouse] = true
        reset_searches
      end
    end
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse helps with this
  def dijkstra_cell_closest_to_mouse
    # Closest cell to the mouse in the first grid
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Bound x and y to the grid
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse in the second grid helps with this
  def greedy_cell_closest_to_mouse
    # Closest cell grid to the mouse in the second
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Translate the cell to the first grid
    x -= grid.width + 1
    # Bound x and y to the first grid
    x = 0 if x < 0
    y = 0 if y < 0
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  # When the user grabs the star and puts their cursor to the far right
  # and moves up and down, the star is supposed to move along the grid as well
  # Finding the cell closest to the mouse in the third grid helps with this
  def a_star_cell_closest_to_mouse
    # Closest cell grid to the mouse in the second
    x = (inputs.mouse.point.x / grid.cell_size).to_i
    y = (inputs.mouse.point.y / grid.cell_size).to_i
    # Translate the cell to the first grid
    x -= (grid.width + 1) * 2
    # Bound x and y to the first grid
    x = 0 if x < 0
    y = 0 if y < 0
    x = grid.width - 1 if x > grid.width - 1
    y = grid.height - 1 if y > grid.height - 1
    # Return closest cell
    [x, y]
  end

  def reset_searches
    # Reset the searches
    dijkstra.came_from      = {}
    dijkstra.cost_so_far    = {}
    dijkstra.frontier       = []
    dijkstra.path           = []

    greedy.came_from = {}
    greedy.frontier  = []
    greedy.path      = []
    a_star.came_from = {}
    a_star.frontier  = []
    a_star.path      = []
  end

  def calc_searches
    calc_dijkstra
    calc_greedy
    calc_a_star
    # Move the searches forward to the current step
    # state.current_step.times { move_searches_one_step_forward }
  end

  def calc_dijkstra
    # Sets up the search to begin from the star
    dijkstra.frontier << grid.star
    dijkstra.came_from[grid.star] = nil
    dijkstra.cost_so_far[grid.star] = 0

    # Until the target is found or there are no more cells to explore from
    until dijkstra.came_from.key?(grid.target) or dijkstra.frontier.empty?
      # Take the next frontier cell. The first element is the cell, the second is the priority.
      new_frontier = dijkstra.frontier.shift#[0]
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do | neighbor |
        # That have not been visited and are not walls
        unless dijkstra.came_from.key?(neighbor) or grid.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited
          dijkstra.frontier << neighbor
          dijkstra.came_from[neighbor] = new_frontier
          dijkstra.cost_so_far[neighbor] = dijkstra.cost_so_far[new_frontier] + 1
        end
      end

      # Sort the frontier so that cells that are in a zigzag pattern are prioritized over those in an line
      # Comment this line and let a path generate to see the difference
      dijkstra.frontier = dijkstra.frontier.sort_by {| cell | proximity_to_star(cell) }
      dijkstra.frontier = dijkstra.frontier.sort_by {| cell | dijkstra.cost_so_far[cell] }
    end


    # If the search found the target
    if dijkstra.came_from.key?(grid.target)
      # Calculate the path between the target and star
      dijkstra_calc_path
    end
  end

  def calc_greedy
    # Sets up the search to begin from the star
    greedy.frontier << grid.star
    greedy.came_from[grid.star] = nil

    # Until the target is found or there are no more cells to explore from
    until greedy.came_from.key?(grid.target) or greedy.frontier.empty?
      # Take the next frontier cell
      new_frontier = greedy.frontier.shift
      # For each of its neighbors
      adjacent_neighbors(new_frontier).each do | neighbor |
        # That have not been visited and are not walls
        unless greedy.came_from.key?(neighbor) or grid.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited
          greedy.frontier << neighbor
          greedy.came_from[neighbor] = new_frontier
        end
      end
      # Sort the frontier so that cells that are in a zigzag pattern are prioritized over those in an line
      # Comment this line and let a path generate to see the difference
      greedy.frontier = greedy.frontier.sort_by {| cell | proximity_to_star(cell) }
      # Sort the frontier so cells that are close to the target are then prioritized
      greedy.frontier = greedy.frontier.sort_by {| cell | greedy_heuristic(cell)  }
    end


    # If the search found the target
    if greedy.came_from.key?(grid.target)
      # Calculate the path between the target and star
      greedy_calc_path
    end
  end

  def calc_a_star
    # Setup the search to start from the star
    a_star.came_from[grid.star] = nil
    a_star.cost_so_far[grid.star] = 0
    a_star.frontier << grid.star

    # Until there are no more cells to explore from or the search has found the target
    until a_star.frontier.empty? or a_star.came_from.key?(grid.target)
      # Get the next cell to expand from
      current_frontier = a_star.frontier.shift

      # For each of that cells neighbors
      adjacent_neighbors(current_frontier).each do | neighbor |
        # That have not been visited and are not walls
        unless a_star.came_from.key?(neighbor) or grid.walls.key?(neighbor)
          # Add them to the frontier and mark them as visited
          a_star.frontier << neighbor
          a_star.came_from[neighbor] = current_frontier
          a_star.cost_so_far[neighbor] = a_star.cost_so_far[current_frontier] + 1
        end
      end

      # Sort the frontier so that cells that are in a zigzag pattern are prioritized over those in an line
      # Comment this line and let a path generate to see the difference
      a_star.frontier = a_star.frontier.sort_by {| cell | proximity_to_star(cell) }
      a_star.frontier = a_star.frontier.sort_by {| cell | a_star.cost_so_far[cell] + greedy_heuristic(cell) }
    end

    # If the search found the target
    if a_star.came_from.key?(grid.target)
      # Calculate the path between the target and star
      a_star_calc_path
    end
  end

  # Calculates the path between the target and star for the breadth first search
  # Only called when the breadth first search finds the target
  def dijkstra_calc_path
    # Start from the target
    endpoint = grid.target
    # And the cell it came from
    next_endpoint = dijkstra.came_from[endpoint]
    while endpoint && next_endpoint
      # Draw a path between these two cells and store it
      path = get_path_between(endpoint, next_endpoint)
      dijkstra.path << path
      # And get the next pair of cells
      endpoint = next_endpoint
      next_endpoint = dijkstra.came_from[endpoint]
      # Continue till there are no more cells
    end
  end

  # Returns one-dimensional absolute distance between cell and target
  # Returns a number to compare distances between cells and the target
  def greedy_heuristic(cell)
    (grid.target.x - cell.x).abs + (grid.target.y - cell.y).abs
  end

  # Calculates the path between the target and star for the greedy search
  # Only called when the greedy search finds the target
  def greedy_calc_path
    # Start from the target
    endpoint = grid.target
    # And the cell it came from
    next_endpoint = greedy.came_from[endpoint]
    while endpoint && next_endpoint
      # Draw a path between these two cells and store it
      path = get_path_between(endpoint, next_endpoint)
      greedy.path << path
      # And get the next pair of cells
      endpoint = next_endpoint
      next_endpoint = greedy.came_from[endpoint]
      # Continue till there are no more cells
    end
  end

  # Calculates the path between the target and star for the a_star search
  # Only called when the a_star search finds the target
  def a_star_calc_path
    # Start from the target
    endpoint = grid.target
    # And the cell it came from
    next_endpoint = a_star.came_from[endpoint]

    while endpoint && next_endpoint
      # Draw a path between these two cells and store it
      path = get_path_between(endpoint, next_endpoint)
      a_star.path << path
      # And get the next pair of cells
      endpoint = next_endpoint
      next_endpoint = a_star.came_from[endpoint]
      # Continue till there are no more cells
    end
  end

  # Returns a list of adjacent cells
  # Used to determine what the next cells to be added to the frontier are
  def adjacent_neighbors(cell)
    neighbors = []

    # Gets all the valid neighbors into the array
    # From southern neighbor, clockwise
    neighbors << [cell.x    , cell.y - 1] unless cell.y == 0
    neighbors << [cell.x - 1, cell.y    ] unless cell.x == 0
    neighbors << [cell.x    , cell.y + 1] unless cell.y == grid.height - 1
    neighbors << [cell.x + 1, cell.y    ] unless cell.x == grid.width - 1

    neighbors
  end

  # Finds the vertical and horizontal distance of a cell from the star
  # and returns the larger value
  # This method is used to have a zigzag pattern in the rendered path
  # A cell that is [5, 5] from the star,
  # is explored before over a cell that is [0, 7] away.
  # So, if possible, the search tries to go diagonal (zigzag) first
  def proximity_to_star(cell)
    distance_x = (grid.star.x - cell.x).abs
    distance_y = (grid.star.y - cell.y).abs

    if distance_x > distance_y
      return distance_x
    else
      return distance_y
    end
  end

  # Methods that allow code to be more concise. Subdivides args.state, which is where all variables are stored.
  def grid
    state.grid
  end

  def dijkstra
    state.dijkstra
  end

  def greedy
    state.greedy
  end

  def a_star
    state.a_star
  end

  # Descriptive aliases for colors
  def default_color
    { r: 221, g: 212, b: 213 }
  end

  def wall_color
    { r: 134, g: 134, b: 120 }
  end

  def visited_color
    { r: 204, g: 191, b: 179 }
  end

  def path_color
    { r: 231, g: 230, b: 228 }
  end

  def button_color
    [190, 190, 190] # Gray
  end
end


# Method that is called by DragonRuby periodically
# Used for updating animations and calculations
def tick args

  # Pressing r will reset the application
  if args.inputs.keyboard.key_down.r
    args.gtk.reset
    reset
    return
  end

  # Every tick, new args are passed, and the Breadth First Search tick is called
  $a_star_algorithm ||= A_Star_Algorithm.new
  $a_star_algorithm.args = args
  $a_star_algorithm.tick
end


def reset
  $a_star_algorithm = nil
end

Tower Defense - main.rb link

# ./samples/13_path_finding_algorithms/09_tower_defense/app/main.rb
# Contributors outside of DragonRuby who also hold Copyright:
# - Sujay Vadlakonda: https://github.com/sujayvadlakonda

# An example of some major components in a tower defence game
# The pathing of the tanks is determined by A* algorithm -- try editing the walls

# The turrets shoot bullets at the closest tank. The bullets are heat-seeking

def tick args
  $gtk.reset if args.inputs.keyboard.key_down.r
  defaults args
  render args
  calc args
end

def defaults args
  args.outputs.background_color = wall_color
  args.state.grid_size = 5
  args.state.tile_size = 50
  args.state.grid_start ||= [0, 0]
  args.state.grid_goal  ||= [4, 4]

  # Try editing these walls to see the path change!
  args.state.walls ||= {
    [0, 4] => true,
    [1, 3] => true,
    [3, 1] => true,
    # [4, 0] => true,
  }

  args.state.a_star.frontier ||= []
  args.state.a_star.came_from ||= {}
  args.state.a_star.path ||= []

  args.state.tanks ||= []
  args.state.tank_spawn_period ||= 60
  args.state.tank_sprite_path ||= 'sprites/circle/white.png'
  args.state.tank_speed ||= 1

  args.state.turret_shoot_period = 10
  # Turrets can be entered as [x, y] but are immediately mapped to hashes
  # Walls are also added where the turrets are to prevent tanks from pathing over them
  args.state.turrets ||= [
    [2, 2]
  ].each { |turret| args.state.walls[turret] = true}.map do |x, y|
    {
      x: x * args.state.tile_size,
      y: y * args.state.tile_size,
      w: args.state.tile_size,
      h: args.state.tile_size,
      path: 'sprites/circle/gray.png',
      range: 100
    }
  end

  args.state.bullet_size ||= 25
  args.state.bullets ||= []
  args.state.bullet_path ||= 'sprites/circle/orange.png'
end

def render args
  render_grid args
  render_a_star args
  args.outputs.sprites << args.state.tanks
  args.outputs.sprites << args.state.turrets
  args.outputs.sprites << args.state.bullets
end

def render_grid args
  # Draw a square the size and color of the grid
  args.outputs.solids << {
    x: 0,
    y: 0,
    w: args.state.grid_size * args.state.tile_size,
    h: args.state.grid_size * args.state.tile_size,
  }.merge(grid_color)

  # Draw lines across the grid to show tiles
  (args.state.grid_size + 1).times do | value |
    render_horizontal_line(args, value)
    render_vertical_line(args, value)
  end

  # Render special tiles
  render_tile(args, args.state.grid_start, start_color)
  render_tile(args, args.state.grid_goal, goal_color)
  args.state.walls.keys.each { |wall| render_tile(args, wall, wall_color) }
end

def render_vertical_line args, x
  args.outputs.lines << {
    x: x * args.state.tile_size,
    y: 0,
    w: 0,
    h: args.state.grid_size * args.state.tile_size
  }
end

def render_horizontal_line args, y
  args.outputs.lines << {
    x: 0,
    y: y * args.state.tile_size,
    w: args.state.grid_size * args.state.tile_size,
    h: 0
  }
end

def render_tile args, tile, color
  args.outputs.solids << {
    x: tile.x * args.state.tile_size,
    y: tile.y * args.state.tile_size,
    w: args.state.tile_size,
    h: args.state.tile_size,
    r: color[0],
    g: color[1],
    b: color[2]
  }
end

def calc args
  calc_a_star args
  calc_tanks args
  calc_turrets args
  calc_bullets args
end

def calc_a_star args
  # Only does this one time
  return unless args.state.a_star.path.empty?

  # Start the search from the grid start
  args.state.a_star.frontier << args.state.grid_start
  args.state.a_star.came_from[args.state.grid_start] = nil

  # Until a path to the goal has been found or there are no more tiles to explore
  until (args.state.a_star.came_from.key?(args.state.grid_goal) || args.state.a_star.frontier.empty?)
    # For the first tile in the frontier
    tile_to_expand_from = args.state.a_star.frontier.shift
    # Add each of its neighbors to the frontier
    neighbors(args, tile_to_expand_from).each do |tile|
      args.state.a_star.frontier << tile
      args.state.a_star.came_from[tile] = tile_to_expand_from
    end
  end

  # Stop calculating a path if the goal was never reached
  return unless args.state.a_star.came_from.key? args.state.grid_goal

  # Fill path by tracing back from the goal
  current_cell = args.state.grid_goal
  while current_cell
    args.state.a_star.path.unshift current_cell
    current_cell = args.state.a_star.came_from[current_cell]
  end

  puts "The path has been calculated"
  puts args.state.a_star.path
end

def calc_tanks args
  spawn_tank args
  move_tanks args
end

def move_tanks args
  # Remove tanks that have reached the end of their path
  args.state.tanks.reject! { |tank| tank[:a_star].empty? }

  # Tanks have an array that has each tile it has to go to in order from a* path
  args.state.tanks.each do | tank |
    destination = tank[:a_star][0]
    # Move the tank towards the destination
    tank[:x] += copy_sign(args.state.tank_speed, ((destination.x * args.state.tile_size) - tank[:x]))
    tank[:y] += copy_sign(args.state.tank_speed, ((destination.y * args.state.tile_size) - tank[:y]))
    # If the tank has reached its destination
    if (destination.x * args.state.tile_size) == tank[:x] &&
        (destination.y * args.state.tile_size) == tank[:y]
      # Set the destination to the next point in the path
      tank[:a_star].shift
    end
  end
end

def calc_turrets args
  return unless Kernel.tick_count.mod_zero? args.state.turret_shoot_period
  args.state.turrets.each do | turret |
    # Finds the closest tank
    target = nil
    shortest_distance = turret[:range] + 1
    args.state.tanks.each do | tank |
      distance = distance_between(turret[:x], turret[:y], tank[:x], tank[:y])
      if distance < shortest_distance
        target = tank
        shortest_distance = distance
      end
    end
    # If there is a tank in range, fires a bullet
    if target
      args.state.bullets << {
        x: turret[:x],
        y: turret[:y],
        w: args.state.bullet_size,
        h: args.state.bullet_size,
        path: args.state.bullet_path,
        # Note that this makes it heat-seeking, because target is passed by reference
        # Could do target.clone to make the bullet go to where the tank initially was
        target: target
      }
    end
  end
end

def calc_bullets args
  # Bullets aim for the center of their targets
  args.state.bullets.each { |bullet| move bullet, center_of(bullet[:target])}
  args.state.bullets.reject! { |b| b.intersect_rect? b[:target] }
end

def center_of object
  object = object.clone
  object[:x] += 0.5
  object[:y] += 0.5
  object
end

def render_a_star args
  args.state.a_star.path.map do |tile|
    # Map each x, y coordinate to the center of the tile and scale up
    [(tile.x + 0.5) * args.state.tile_size, (tile.y + 0.5) * args.state.tile_size]
  end.inject do | point_a,  point_b |
    # Render the line between each point
    args.outputs.lines << [point_a.x, point_a.y, point_b.x, point_b.y, a_star_color]
    point_b
  end
end

# Moves object to target at speed
def move object, target, speed = 1
  if target.is_a? Hash
    object[:x] += copy_sign(speed, target[:x] - object[:x])
    object[:y] += copy_sign(speed, target[:y] - object[:y])
  else
    object[:x] += copy_sign(speed, target.x - object[:x])
    object[:y] += copy_sign(speed, target.y - object[:y])
  end
end


def distance_between a_x, a_y, b_x, b_y
  (((b_x - a_x) ** 2) + ((b_y - a_y) ** 2)) ** 0.5
end

def copy_sign value, sign
  return 0 if sign == 0
  return value if sign > 0
  -value
end

def spawn_tank args
  return unless Kernel.tick_count.mod_zero? args.state.tank_spawn_period
  args.state.tanks << {
    x: args.state.grid_start.x,
    y: args.state.grid_start.y,
    w: args.state.tile_size,
    h: args.state.tile_size,
    path: args.state.tank_sprite_path,
    a_star: args.state.a_star.path.clone
  }
end

def neighbors args, tile
  [[tile.x, tile.y - 1],
   [tile.x, tile.y + 1],
   [tile.x + 1, tile.y],
   [tile.x - 1, tile.y]].reject do |neighbor|
    args.state.a_star.came_from.key?(neighbor) || tile_out_of_bounds?(args, neighbor) ||
      args.state.walls.key?(neighbor)
  end
end

def tile_out_of_bounds? args, tile
  tile.x < 0 || tile.y < 0 || tile.x >= args.state.grid_size || tile.y >= args.state.grid_size
end

def grid_color
  { r: 133, g: 226, b: 144 }
end

def start_color
  [226, 144, 133]
end

def goal_color
  [226, 133, 144]
end

def wall_color
  [133, 144, 226]
end

def a_star_color
  [0, 0, 255]
end

Moveable Squares - main.rb link

# ./samples/13_path_finding_algorithms/10_moveable_squares/app/main.rb
class Game
  attr_gtk

  def tick
    defaults
    calc
    render
  end

  def defaults
    state.square_size ||= 16
    if !state.world
      state.world = {
        w: 80,
        h: 45,
        player: {
          x: 15,
          y: 15,
          speed: 6
        },
        walls: [
          { x: 16, y: 16 },
          { x: 15, y: 16 },
          { x: 14, y: 17 },
          { x: 14, y: 13 },
          { x: 15, y: 13 },
          { x: 16, y: 13 },
          { x: 17, y: 13 }
        ]
      }
    end
  end

  def calc
    player = world.player
    player.rect = { x: player.x * state.square_size, y: player.y * state.square_size, w: state.square_size, h: state.square_size }
    player.moveable_squares = entity_moveable_squares world.player
    if inputs.keyboard.key_down.plus
      state.world.player.speed += 1
    elsif inputs.keyboard.key_down.minus
      state.world.player.speed -= 1
      state.world.player.speed = 1 if state.world.player.speed < 1
    end

    mouse_ordinal_x = inputs.mouse.x.idiv state.square_size
    mouse_ordinal_y = inputs.mouse.y.idiv state.square_size

    if inputs.mouse.click
      if world.walls.any? { |enemy| enemy.x == mouse_ordinal_x && enemy.y == mouse_ordinal_y }
        world.walls.reject! { |enemy| enemy.x == mouse_ordinal_x && enemy.y == mouse_ordinal_y }
      else
        world.walls << { x: mouse_ordinal_x, y: mouse_ordinal_y, speed: 3 }
      end
    end

    state.hovered_square = world.player.moveable_squares.find do |square|
      mouse_ordinal_x == square.x && mouse_ordinal_y == square.y
    end
  end

  def render
    outputs.primitives << { x: 30, y: 30.from_top, text: "+/- to increase decrease movement radius." }
    outputs.primitives << { x: 30, y: 60.from_top, text: "click to add/remove wall." }
    outputs.primitives << { x: 30, y: 90.from_top, text: "FPS: #{$gtk.current_framerate.to_sf}" }
    if Kernel.tick_count <= 1
      outputs[:world_grid].w = 1280
      outputs[:world_grid].h = 720
      outputs[:world_grid].primitives << state.world.w.flat_map do |x|
        state.world.h.map do |y|
          {
            x: x * state.square_size,
            y: y * state.square_size,
            w: state.square_size,
            h: state.square_size,
            r: 0,
            g: 0,
            b: 0,
            a: 128
          }.border!
        end
      end
    end

    outputs[:world_overlay].w = 1280
    outputs[:world_overlay].h = 720

    if state.hovered_square
      outputs[:world_overlay].primitives << path_to_square_prefab(state.hovered_square)
    end

    outputs[:world_overlay].primitives << world.player.moveable_squares.map do |square|
      square_prefab square, { r: 0, g: 0, b: 128, a: 128 }
    end

    outputs[:world_overlay].primitives << world.walls.map do |enemy|
      square_prefab enemy, { r: 128, g: 0, b: 0, a: 200 }
    end

    outputs[:world_overlay].primitives << square_prefab(world.player, { r: 0, g: 128, b: 0, a: 200 })

    outputs[:world].w = 1280
    outputs[:world].h = 720
    outputs[:world].primitives << { x: 0, y: 0, w: 1280, h: 720, path: :world_grid }
    outputs[:world].primitives << { x: 0, y: 0, w: 1280, h: 720, path: :world_overlay }
    outputs.primitives << { x: 0, y: 0, w: 1280, h: 720, path: :world }
  end

  def square_prefab square, color
    {
      x: square.x * state.square_size,
      y: square.y * state.square_size,
      w: state.square_size,
      h: state.square_size,
      **color,
      path: :solid
    }
  end

  def path_to_square_prefab moveable_square
    prefab = []
    color = { r: 0, g: 0, b: 128, a: 80 }
    if moveable_square
      prefab << square_prefab(moveable_square, color)
      prefab << path_to_square_prefab(moveable_square.source)
    end
    prefab
  end

  def world
    state.world
  end

  def entity_moveable_squares entity
    results = {}
    queue = {}
    queue[entity.x] ||= {}
    queue[entity.x][entity.y] = entity
    entity_moveable_squares_recur queue, results while !queue.empty?
    results.flat_map do |x, ys|
      ys.map do |y, value|
        value
      end
    end
  end

  def entity_moveable_squares_recur queue, results
    x, ys = queue.first
    return if !x
    return if !ys
    y, to_process = ys.first
    return if !to_process
    queue[to_process.x].delete y
    queue.delete x if queue[x].empty?
    return if results[to_process.x] && results[to_process.x] && results[to_process.x][to_process.y]

    neighbors = MoveableLocations.neighbors world, to_process
    neighbors.each do |neighbor|
      if !queue[neighbor.x] || !queue[neighbor.x][neighbor.y]
        queue[neighbor.x] ||= {}
        queue[neighbor.x][neighbor.y] = neighbor
      end
    end

    results[to_process.x] ||= {}
    results[to_process.x][to_process.y] = to_process
  end
end

class MoveableLocations
  class << self
    def neighbors world, square
      return [] if !square
      return [] if square.speed <= 0
      north_square = { x: square.x, y: square.y + 1, speed: square.speed - 1, source: square }
      south_square = { x: square.x, y: square.y - 1, speed: square.speed - 1, source: square }
      east_square  = { x: square.x + 1, y: square.y, speed: square.speed - 1, source: square }
      west_square  = { x: square.x - 1, y: square.y, speed: square.speed - 1, source: square }
      north_east_square = { x: square.x + 1, y: square.y + 1, speed: square.speed - 2, source: square }
      north_west_square = { x: square.x - 1, y: square.y + 1, speed: square.speed - 2, source: square }
      south_east_square = { x: square.x + 1, y: square.y - 1, speed: square.speed - 2, source: square }
      south_west_square = { x: square.x - 1, y: square.y - 1, speed: square.speed - 2, source: square }
      result = []
      north_available = valid? world, north_square
      south_available = valid? world, south_square
      east_available  = valid? world, east_square
      west_available  = valid? world, west_square
      north_east_available = valid? world, north_east_square
      north_west_available = valid? world, north_west_square
      south_east_available = valid? world, south_east_square
      south_west_available = valid? world, south_west_square
      result << north_square if north_available
      result << south_square if south_available
      result << east_square  if east_available
      result << west_square  if west_available
      result << north_east_square if north_available && east_available && north_east_available
      result << north_west_square if north_available && west_available && north_west_available
      result << south_east_square if south_available && east_available && south_east_available
      result << south_west_square if south_available && west_available && south_west_available
      result
    end

    def valid? world, square
      return false if !square
      return false if square.speed < 0
      return false if square.x < 0 || square.x >= world.w || square.y < 0 || square.y >= world.h
      return false if world.walls.any? { |enemy| enemy.x == square.x && enemy.y == square.y }
      return false if world.player.x == square.x && world.player.y == square.y
      return true
    end
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

$gtk.reset

Vr link

Skybox - main.rb link

# ./samples/14_vr/01_skybox/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  tick_game args
end

Skybox - tick.rb link

# ./samples/14_vr/01_skybox/app/tick.rb
def skybox args, x, y, z, size
  sprite = { a: 80, path: 'sprites/box.png' }

  front      = { x: x, y: y, z: z, w: size, h: size, **sprite }
  front_720  = { x: x, y: y, z: z + 1, w: size, h: size * 9.fdiv(16), **sprite }
  back       = { x: x, y: y, z: z + size, w: size, h: size, **sprite }
  bottom     = { x: x, y: y - size.half, z: z + size.half, w: size, h: size, angle_x: 90, **sprite }
  top        = { x: x, y: y + size.half, z: z + size.half, w: size, h: size, angle_x: 90, **sprite }
  left       = { x: x - size.half, y: y, w: size, h: size, z: z + size.half, angle_y: 90, **sprite }
  right      = { x: x + size.half, y: y, w: size, h: size, z: z + size.half, angle_y: 90, **sprite }

  args.outputs.sprites << [back,
                           left,
                           top,
                           bottom,
                           right,
                           front,
                           front_720]
end

def tick_game args
  args.outputs.background_color = [0, 0, 0]

  args.state.z     ||= 0
  args.state.scale ||= 0.05

  if args.inputs.controller_one.key_down.a
    if args.grid.name == :bottom_left
      args.grid.origin_center!
    else
      args.grid.origin_bottom_left!
    end
  end

  args.state.scale += args.inputs.controller_one.right_analog_x_perc * 0.01
  args.state.z -= args.inputs.controller_one.right_analog_y_perc * 1.5

  args.state.scale = args.state.scale.clamp(0.05, 1.0)
  args.state.z = 0    if args.state.z < 0
  args.state.z = 1280 if args.state.z > 1280

  skybox args, 0, 0, args.state.z, 1280 * args.state.scale

  render_guides args
end

def render_guides args
  label_style = { alignment_enum: 1,
                  size_enum: -2,
                  vertical_alignment_enum: 0, r: 255, g: 255, b: 255 }

  instructions = [
    "controller position: #{args.inputs.controller_one.left_hand.x} #{args.inputs.controller_one.left_hand.y} #{args.inputs.controller_one.left_hand.z}",
    "scale: #{args.state.scale.to_sf} (right analog left/right)",
    "z: #{args.state.z.to_sf} (right analog up/down)",
    "origin: :#{args.grid.name} (A button)",
  ]

  args.outputs.labels << instructions.map_with_index do |text, i|
    { x: 640,
      y: 100 + ((instructions.length - (i + 3)) * 22),
      z: args.state.z + 2,
      a: 255,
      text: text,
      ** label_style,
      alignment_enum: 1,
      vertical_alignment_enum: 0 }
  end

  # lines for scaled box
  size      = 1280 * args.state.scale
  size_16_9 = size * 9.fdiv(16)

  args.outputs.primitives << [
    { x: size - 1280, y: size,        z:            0, w: 1280 * 2, r: 128, g: 128, b: 128, a:  64 }.line!,
    { x: size - 1280, y: size,        z: args.state.z + 2, w: 1280 * 2, r: 128, g: 128, b: 128, a: 255 }.line!,

    { x: size - 1280, y: size_16_9,   z:            0, w: 1280 * 2, r: 128, g: 128, b: 128, a:  64 }.line!,
    { x: size - 1280, y: size_16_9,   z: args.state.z + 2, w: 1280 * 2, r: 128, g: 128, b: 128, a: 255 }.line!,

    { x: size,        y: size - 1280, z:            0, h: 1280 * 2, r: 128, g: 128, b: 128, a:  64 }.line!,
    { x: size,        y: size - 1280, z: args.state.z + 2, h: 1280 * 2, r: 128, g: 128, b: 128, a: 255 }.line!,

    { x: size,        y: size,        z: args.state.z + 3, size_enum: -2,
      vertical_alignment_enum: 0,
      text: "#{size.to_sf}, #{size.to_sf}, #{args.state.z.to_sf}",
      r: 255, g: 255, b: 255, a: 255 }.label!,

    { x: size,        y: size_16_9,   z: args.state.z + 3, size_enum: -2,
      vertical_alignment_enum: 0,
      text: "#{size.to_sf}, #{size_16_9.to_sf}, #{args.state.z.to_sf}",
      r: 255, g: 255, b: 255, a: 255 }.label!,
  ]

  xs = [
    { description: "left",   x:    0, alignment_enum: 0 },
    { description: "center", x:  640, alignment_enum: 1 },
    { description: "right",  x: 1280, alignment_enum: 2 },
  ]

  ys = [
    { description: "bottom",        y:    0, vertical_alignment_enum: 0 },
    { description: "center",        y:  640, vertical_alignment_enum: 1 },
    { description: "center (720p)", y:  360, vertical_alignment_enum: 1 },
    { description: "top",           y: 1280, vertical_alignment_enum: 2 },
    { description: "top (720p)",    y:  720, vertical_alignment_enum: 2 },
  ]

  args.outputs.primitives << xs.product(ys).map do |(xdef, ydef)|
    [
      { x: xdef.x,
        y: ydef.y,
        z: args.state.z + 3,
        text: "#{xdef.x.to_sf}, #{ydef.y.to_sf} #{args.state.z.to_sf}",
        **label_style,
        alignment_enum: xdef.alignment_enum,
        vertical_alignment_enum: ydef.vertical_alignment_enum
      },
      { x: xdef.x,
        y: ydef.y - 20,
        z: args.state.z + 3,
        text: "#{ydef.description}, #{xdef.description}",
        **label_style,
        alignment_enum: xdef.alignment_enum,
        vertical_alignment_enum: ydef.vertical_alignment_enum
      }
    ]
  end

  args.outputs.primitives << xs.product(ys).map do |(xdef, ydef)|
    [
      {
        x: xdef.x - 1280,
        y: ydef.y,
        w: 1280 * 2,
        a: 64,
        r: 128, g: 128, b: 128
      }.line!,
      {
        x: xdef.x,
        y: ydef.y - 720,
        h: 720 * 2,
        a: 64,
        r: 128, g: 128, b: 128
      }.line!,
    ].map do |p|
      [
        p.merge(z:            0, a:  64),
        p.merge(z: args.state.z + 2, a: 255)
      ]
    end
  end
end

$gtk.reset

Top Down Rpg - main.rb link

# ./samples/14_vr/02_top_down_rpg/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  tick_game args
end

Top Down Rpg - tick.rb link

# ./samples/14_vr/02_top_down_rpg/app/tick.rb
class Game
  attr_gtk

  def tick
    outputs.background_color = [0, 0, 0]
    args.state.tile_size     = 80
    args.state.player_speed  = 4
    args.state.player      ||= tile(args, 7, 3, 0, 128, 180)
    generate_map args

    # adds walls, goal, and player to args.outputs.solids so they appear on screen
    args.outputs.solids << args.state.goal
    args.outputs.solids << args.state.walls
    args.outputs.solids << args.state.player

    args.outputs.solids << args.state.walls.map { |s| s.to_hash.merge(z: 2, g: 80) }
    args.outputs.solids << args.state.walls.map { |s| s.to_hash.merge(z: 10, g: 255, a: 50) }

    # if player's box intersects with goal, a label is output onto the screen
    if args.state.player.intersect_rect? args.state.goal
      args.outputs.labels << { x: 640,
                               y: 360,
                               z: 10,
                               text: "YOU'RE A GOD DAMN WIZARD, HARRY.",
                               size_enum: 10,
                               alignment_enum: 1,
                               vertical_alignment_enum: 1,
                               r: 255,
                               g: 255,
                               b: 255 }
    end

    move_player args, -1,  0 if args.inputs.keyboard.left  || args.inputs.controller_one.left # x position decreases by 1 if left key is pressed
    move_player args,  1,  0 if args.inputs.keyboard.right || args.inputs.controller_one.right # x position increases by 1 if right key is pressed
    move_player args,  0, -1 if args.inputs.keyboard.up    || args.inputs.controller_one.down # y position increases by 1 if up is pressed
    move_player args,  0,  1 if args.inputs.keyboard.down  || args.inputs.controller_one.up # y position decreases by 1 if down is pressed
  end

  # Sets position, size, and color of the tile
  def tile args, x, y, *color
    [x * args.state.tile_size, # sets definition for array using method parameters
     y * args.state.tile_size, # multiplying by tile_size sets x and y to correct position using pixel values
     args.state.tile_size,
     args.state.tile_size,
     *color]
  end

  # Creates map by adding tiles to the wall, as well as a goal (that the player needs to reach)
  def generate_map args
    return if args.state.area

    # Creates the area of the map. There are 9 rows running horizontally across the screen
    # and 16 columns running vertically on the screen. Any spot with a "1" is not
    # open for the player to move into (and is green), and any spot with a "0" is available
    # for the player to move in.
    args.state.area = [
      [1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1,],
      [1, 1, 1, 2, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1,], # the "2" represents the goal
      [1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1,],
      [1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1,],
      [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,],
      [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,],
      [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,],
      [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,],
      [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ],
    ].reverse # reverses the order of the area collection

    # By reversing the order, the way that the area appears above is how it appears
    # on the screen in the game. If we did not reverse, the map would appear inverted.

    #The wall starts off with no tiles.
    args.state.walls = []

    # If v is 1, a green tile is added to args.state.walls.
    # If v is 2, a black tile is created as the goal.
    args.state.area.map_2d do |y, x, v|
      if    v == 1
        args.state.walls << tile(args, x, y, 0, 255, 0) # green tile
      elsif v == 2 # notice there is only one "2" above because there is only one single goal
        args.state.goal   = tile(args, x, y, 180,  0, 0) # black tile
      end
    end
  end

  # Allows the player to move their box around the screen
  def move_player args, *vector
    box = args.state.player.shift_rect(vector) # box is able to move at an angle

    # If the player's box hits a wall, it is not able to move further in that direction
    return if args.state.walls
                .any_intersect_rect?(box)

    # Player's box is able to move at angles (not just the four general directions) fast
    args.state.player =
      args.state.player
        .shift_rect(vector.x * args.state.player_speed, # if we don't multiply by speed, then
                    vector.y * args.state.player_speed) # the box will move extremely slow
  end
end

$game = Game.new

def tick_game args
  $game.args = args
  $game.tick
end

$gtk.reset

Space Invaders - main.rb link

# ./samples/14_vr/03_space_invaders/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  tick_game args
end

Space Invaders - tick.rb link

# ./samples/14_vr/03_space_invaders/app/tick.rb
class Game
  attr_gtk

  def tick
    grid.origin_center!
    defaults
    outputs.background_color = [0, 0, 0]
    args.outputs.sprites << state.enemies.map { |e| enemy_prefab e }.to_a
  end

  def defaults
    state.enemy_sprite_size = 64
    state.row_size = 16
    state.max_rows = 20
    state.enemies ||= 32.map_with_index do |i|
      x = i % 16
      y = i.idiv 16
      { row: y, col: x }
    end
  end

  def enemy_prefab enemy
    if enemy.row > state.max_rows
      raise "#{enemy}"
    end
    relative_row = enemy.row + 1
    z = 50 - relative_row * 10
    x = (enemy.col * state.enemy_sprite_size) - (state.enemy_sprite_size * state.row_size).idiv(2)
    enemy_sprite(x, enemy.row * 10 + 100, z * 10, enemy)
  end

  def enemy_sprite x, y, z, meta
    index = 0.frame_index count: 2, hold_for: 50, repeat: true
    { x: x,
      y: y,
      z: z,
      w: state.enemy_sprite_size,
      h: state.enemy_sprite_size,
      path: 'sprites/enemy.png',
      source_x: 128 * index,
      source_y: 0,
      source_w: 128,
      source_h: 128,
      meta: meta }
  end
end

$game = Game.new

def tick_game args
  $game.args = args
  $game.tick
end

$gtk.reset

Let There Be Light - main.rb link

# ./samples/14_vr/04_let_there_be_light/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  tick_game args
end

Let There Be Light - tick.rb link

# ./samples/14_vr/04_let_there_be_light/app/tick.rb
class Game
  attr_gtk

  def tick
    grid.origin_center!
    defaults
    state.angle_shift_x ||= 180
    state.angle_shift_y ||= 180

    if inputs.controller_one.right_analog_y_perc.round(2) != 0.00
      args.state.star_distance += (inputs.controller_one.right_analog_y_perc * 0.25) ** 2 * inputs.controller_one.right_analog_y_perc.sign
      state.star_distance = state.star_distance.clamp(state.min_star_distance, state.max_star_distance)
      state.star_sprites = calc_star_primitives
    elsif inputs.controller_one.down
      args.state.star_distance += (1.0 * 0.25) ** 2
      state.star_distance = state.star_distance.clamp(state.min_star_distance, state.max_star_distance)
      state.star_sprites = calc_star_primitives
    elsif inputs.controller_one.up
      args.state.star_distance -= (1.0 * 0.25) ** 2
      state.star_distance = state.star_distance.clamp(state.min_star_distance, state.max_star_distance)
      state.star_sprites = calc_star_primitives
    end

    render
  end

  def calc_star_primitives
    args.state.stars.map do |s|
      w = (32 * state.star_distance).clamp(1, 32)
      h = (32 * state.star_distance).clamp(1, 32)
      x = (state.max.x * state.star_distance) * s.xr
      y = (state.max.y * state.star_distance) * s.yr
      z = state.center.z + (state.max.z * state.star_distance * 10 * s.zr)

      angle_x = Math.atan2(z - 600, y).to_degrees + 90
      angle_y = Math.atan2(z - 600, x).to_degrees + 90

      draw_x = x - w.half
      draw_y = y - 40 - h.half
      draw_z = z

      { x: draw_x,
        y: draw_y,
        z: draw_z,
        b: 255,
        w: w,
        h: h,
        angle_x: angle_x,
        angle_y: angle_y,
        path: 'sprites/star.png' }
    end
  end

  def render
    outputs.background_color = [0, 0, 0]
    if state.star_distance <= 1.0
      text_alpha = (1 - state.star_distance) * 255
      args.outputs.labels << { x: 0, y: 50, text: "Let there be light.", r: 255, g: 255, b: 255, size_enum: 1, alignment_enum: 1, a: text_alpha }
      args.outputs.labels << { x: 0, y: 25, text: "(right analog: up/down)", r: 255, g: 255, b: 255, size_enum: -2, alignment_enum: 1, a: text_alpha }
    end

    args.outputs.sprites << state.star_sprites
  end

  def random_point
    r = { xr: 2.randomize(:ratio) - 1,
          yr: 2.randomize(:ratio) - 1,
          zr: 2.randomize(:ratio) - 1 }
    if (r.xr ** 2 + r.yr ** 2 + r.zr ** 2) > 1.0
      return random_point
    else
      return r
    end
  end

  def defaults
    state.max_star_distance ||= 100
    state.min_star_distance ||= 0.001
    state.star_distance     ||= 0.001
    state.star_angle        ||= 0

    state.center.x       ||= 0
    state.center.y       ||= 0
    state.center.z       ||= 30
    state.max.x          ||= 640
    state.max.y          ||= 640
    state.max.z          ||= 50

    state.stars ||= 1500.map do
      random_point
    end

    state.star_sprites ||= calc_star_primitives
  end
end

$game = Game.new

def tick_game args
  $game.args = args
  $game.tick
end

$gtk.reset

Draw A Cube - main.rb link

# ./samples/14_vr/05_draw_a_cube/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  tick_game args
end

Draw A Cube - tick.rb link

# ./samples/14_vr/05_draw_a_cube/app/tick.rb
def cube args, x, y, z, size
  sprite = { w: size, h: size, path: 'sprites/square/blue.png', a: 80 }
  back   = { x: x,                 y: y,                 z: z - size.half + 1,              **sprite }
  front  = { x: x,                 y: y,                 z: z + size.half - 1,              **sprite }
  top    = { x: x,                 y: y + size.half - 1, z: z,                 angle_x: 90, **sprite }
  bottom = { x: x,                 y: y - size.half + 1, z: z,                 angle_x: 90, **sprite }
  left   = { x: x - size.half + 1, y: y,                 z: z,                 angle_y: 90, **sprite }
  right  = { x: x + size.half - 1, y: y,                 z: z,                 angle_y: 90, **sprite }

  args.outputs.sprites << [back, left, top, bottom, right, front]
end

def tick_game args
  args.grid.origin_center!
  args.outputs.background_color = [0, 0, 0]

  args.state.x ||= 0
  args.state.y ||= 0

  args.state.x += 10 * args.inputs.controller_one.right_analog_x_perc
  args.state.y += 10 * args.inputs.controller_one.right_analog_y_perc

  cube args, args.state.x, args.state.y, 0, 100
end

Draw A Cube With Triangles - main.rb link

# ./samples/14_vr/05_draw_a_cube_with_triangles/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  tick_game args
end

Draw A Cube With Triangles - tick.rb link

# ./samples/14_vr/05_draw_a_cube_with_triangles/app/tick.rb
include MatrixFunctions

def tick args
  args.grid.origin_center!

  # model A
  args.state.a = [
    [vec4(0, 0, 0, 1),   vec4(0.1, 0, 0, 1),   vec4(0, 0.1, 0, 1)],
    [vec4(0.1, 0, 0, 1), vec4(0.1, 0.1, 0, 1), vec4(0, 0.1, 0, 1)]
  ]

  # model to world
  args.state.back = mul_triangles args,
                                  args.state.a,
                                  (translate -0.05, -0.05, 0),
                                  (translate 0, 0, -0.05),
                                  (rotate_x Kernel.tick_count),
                                  (rotate_y Kernel.tick_count),
                                  (rotate_z Kernel.tick_count)

  args.state.front = mul_triangles args,
                                   args.state.a,
                                   (translate -0.05, -0.05, 0),
                                   (translate 0, 0, 0.05),
                                   (rotate_x Kernel.tick_count),
                                   (rotate_y Kernel.tick_count),
                                   (rotate_z Kernel.tick_count)

  args.state.left = mul_triangles args,
                                  args.state.a,
                                  (translate -0.05, -0.05, 0),
                                  (rotate_y 90),
                                  (translate -0.05, 0, 0),
                                  (rotate_x Kernel.tick_count),
                                  (rotate_y Kernel.tick_count),
                                  (rotate_z Kernel.tick_count)

  args.state.right = mul_triangles args,
                                   args.state.a,
                                   (translate -0.05, -0.05, 0),
                                   (rotate_y 90),
                                   (translate  0.05, 0, 0),
                                   (rotate_x Kernel.tick_count),
                                   (rotate_y Kernel.tick_count),
                                   (rotate_z Kernel.tick_count)

  args.state.top = mul_triangles args,
                                 args.state.a,
                                 (translate -0.05, -0.05, 0),
                                 (rotate_x 90),
                                 (translate 0, 0.05, 0),
                                 (rotate_x Kernel.tick_count),
                                 (rotate_y Kernel.tick_count),
                                 (rotate_z Kernel.tick_count)

  args.state.bottom = mul_triangles args,
                                    args.state.a,
                                    (translate -0.05, -0.05, 0),
                                    (rotate_x 90),
                                    (translate 0, -0.05, 0),
                                    (rotate_x Kernel.tick_count),
                                    (rotate_y Kernel.tick_count),
                                    (rotate_z Kernel.tick_count)

  render_square args, args.state.back
  render_square args, args.state.front
  render_square args, args.state.left
  render_square args, args.state.right
  render_square args, args.state.top
  render_square args, args.state.bottom
end

def render_square args, triangles
  args.outputs.sprites << { x:  triangles[0][0].x * 1280,
                            y:  triangles[0][0].y * 1280,
                            z:  triangles[0][0].z * 1280,
                            x2: triangles[0][1].x * 1280,
                            y2: triangles[0][1].y * 1280,
                            z2: triangles[0][1].z * 1280,
                            x3: triangles[0][2].x * 1280,
                            y3: triangles[0][2].y * 1280,
                            z3: triangles[0][2].z * 1280,
                            a: 255,
                            source_x:   0,
                            source_y:   0,
                            source_x2: 80,
                            source_y2:  0,
                            source_x3:  0,
                            source_y3: 80,
                            path: 'sprites/square/red.png' }

  args.outputs.sprites << { x:  triangles[1][0].x * 1280,
                            y:  triangles[1][0].y * 1280,
                            z:  triangles[1][0].z * 1280,
                            x2: triangles[1][1].x * 1280,
                            y2: triangles[1][1].y * 1280,
                            z2: triangles[1][1].z * 1280,
                            x3: triangles[1][2].x * 1280,
                            y3: triangles[1][2].y * 1280,
                            z3: triangles[1][2].z * 1280,
                            a: 255,
                            source_x:  80,
                            source_y:   0,
                            source_x2: 80,
                            source_y2: 80,
                            source_x3:  0,
                            source_y3: 80,
                            path: 'sprites/square/red.png' }
end

def mul_triangles args, triangles, *mul_def
  triangles.map do |vecs|
    vecs.map do |vec|
      mul vec, *mul_def
    end
  end
end

def scale scale
  mat4 scale,     0,     0,   0,
           0, scale,     0,   0,
           0,     0, scale,   0,
           0,     0,     0,   1
end

def rotate_y angle_d
  cos_t = Math.cos angle_d.to_radians
  sin_t = Math.sin angle_d.to_radians
  mat4  cos_t,  0, sin_t, 0,
        0,      1, 0,     0,
        -sin_t, 0, cos_t, 0,
        0,      0, 0,     1
end

def rotate_z angle_d
  cos_t = Math.cos angle_d.to_radians
  sin_t = Math.sin angle_d.to_radians
  mat4 cos_t, -sin_t, 0, 0,
       sin_t,  cos_t, 0, 0,
       0,      0,     1, 0,
       0,      0,     0, 1
end

def translate dx, dy, dz
  mat4 1, 0, 0, dx,
       0, 1, 0, dy,
       0, 0, 1, dz,
       0, 0, 0,  1
end


def rotate_x angle_d
  cos_t = Math.cos angle_d.to_radians
  sin_t = Math.sin angle_d.to_radians
  mat4  1,     0,      0, 0,
        0, cos_t, -sin_t, 0,
        0, sin_t,  cos_t, 0,
        0,     0,      0, 1
end

Gimbal Lock - main.rb link

# ./samples/14_vr/05_gimbal_lock/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  $game ||= Game.new
  $game.args = args
  $game.tick
end

Gimbal Lock - tick.rb link

# ./samples/14_vr/05_gimbal_lock/app/tick.rb
class Game
  attr_gtk

  def tick
    grid.origin_center!
    state.angle_x ||= 0
    state.angle_y ||= 0
    state.angle_z ||= 0

    if inputs.left
      state.angle_z += 1
    elsif inputs.right
      state.angle_z -= 1
    end

    if inputs.up
      state.angle_x += 1
    elsif inputs.down
      state.angle_x -= 1
    end

    if inputs.controller_one.a
      state.angle_y += 1
    elsif inputs.controller_one.b
      state.angle_y -= 1
    end

    outputs.sprites << {
      x: 0,
      y: 0,
      w: 100,
      h: 100,
      path: 'sprites/square/blue.png',
      angle_x: state.angle_x,
      angle_y: state.angle_y,
      angle: state.angle_z,
    }
  end
end

Citadels - main.rb link

# ./samples/14_vr/06_citadels/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  $game ||= Game.new
  $game.args = args
  $game.tick
end

Citadels - tick.rb link

# ./samples/14_vr/06_citadels/app/tick.rb
class Game
  attr_gtk

  def citadel x, y, z
    angle = Kernel.tick_count.idiv(10) % 360
    adjacent = 40
    adjacent = adjacent.ceil
    angle = Math.atan2(40, 70).to_degrees
    y += 500
    x -= 40
    back_sprites = [
      { z: z - 40 + adjacent.half,
        x: x,
        y: y + 75,
        w: 80, h: 80, angle_x: angle, path: "sprites/triangle/equilateral/blue.png" },
      { z: z - 40,
        x: x,
        y: y - 400 + 80,
        w: 80, h: 400, path: "sprites/square/blue.png" },
    ]

    left_sprites = [
      { z: z,
        x: x - 40 + adjacent.half,
        y: y + 75,
        w: 80, h: 80, angle_x: -angle, angle_y: 90, path: "sprites/triangle/equilateral/blue.png" },
      { z: z,                      x: x - 40,
        y: y - 400 + 80,
        w: 80, h: 400, angle_y: 90, path: "sprites/square/blue.png" },
    ]

    right_sprites = [
      { z: z,
        x: x + 40 - adjacent.half,
        y: y + 75,
        w: 80, h: 80, angle_x: angle, angle_y: 90, path: "sprites/triangle/equilateral/blue.png" },
      { z: z,
        x: x + 40,
        y: y - 400 + 80,
        w: 80, h: 400, angle_y: 90, path: "sprites/square/blue.png" },
    ]

    front_sprites = [
      { z: z + 40 - adjacent.half,
        x: x,
        y: y + 75,
        w: 80, h: 80, angle_x: -angle, path: "sprites/triangle/equilateral/blue.png" },
      { z: z + 40,
        x: x,
        y: y - 400 + 80,
        w: 80, h: 400, path: "sprites/square/blue.png" },
    ]

    if x > 700
      [
        back_sprites,
        right_sprites,
        front_sprites,
        left_sprites,
      ]
    elsif x < 600
      [
        back_sprites,
        left_sprites,
        front_sprites,
        right_sprites,
      ]
    else
      [
        back_sprites,
        left_sprites,
        right_sprites,
        front_sprites,
      ]
    end

  end

  def tick
    state.z ||= 200
    state.z += inputs.controller_one.right_analog_y_perc
    state.columns ||= 100.map do
      {
        x: rand(12) * 400,
        y: 0,
        z: rand(12) * 400,
      }
    end

    outputs.sprites << state.columns.map do |col|
      citadel(col.x - 640, col.y - 400, state.z - col.z)
    end
  end
end

$game = Game.new

def tick_game args
  $game.args = args
  $game.tick
end

$gtk.reset

Flappy credits.txt link

# ./samples/14_vr/07_flappy_vr/CREDITS.txt
code: Amir Rajan, https://twitter.com/amirrajan
graphics and audio: Nick Culbertson, https://twitter.com/MobyPixel

Flappy main.rb link

# ./samples/14_vr/07_flappy_vr/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  tick_game args
end

Flappy tick.rb link

# ./samples/14_vr/07_flappy_vr/app/tick.rb
class FlappyDragon
  attr_accessor :grid, :inputs, :state, :outputs

  def background_z
    -640
  end

  def flappy_sprite_z
    -120
  end

  def game_text_z
    0
  end

  def menu_overlay_z
    10
  end

  def menu_text_z
    menu_overlay_z + 1
  end

  def flash_z
    1
  end

  def tick
    defaults
    render
    calc
    process_inputs
  end

  def defaults
    state.flap_power              = 11
    state.gravity                 = 0.9
    state.ceiling                 = 600
    state.ceiling_flap_power      = 6
    state.wall_countdown_length   = 100
    state.wall_gap_size           = 100
    state.wall_countdown        ||= 0
    state.hi_score              ||= 0
    state.score                 ||= 0
    state.walls                 ||= []
    state.x_starting_point      ||= 640
    state.x                     ||= state.x_starting_point
    state.y                     ||= 500
    state.z                     ||= -120
    state.dy                    ||= 0
    state.scene                 ||= :menu
    state.scene_at              ||= 0
    state.difficulty            ||= :normal
    state.new_difficulty        ||= :normal
    state.countdown             ||= 4.seconds
    state.flash_at              ||= 0
  end

  def render
    outputs.sounds << "sounds/flappy-song.ogg" if Kernel.tick_count == 1
    render_score
    render_menu
    render_game
  end

  def render_score
    outputs.primitives << { x: 10, y: 710, z: game_text_z, text: "HI SCORE: #{state.hi_score}", **large_white_typeset }
    outputs.primitives << { x: 10, y: 680, z: game_text_z, text: "SCORE: #{state.score}", **large_white_typeset }
    outputs.primitives << { x: 10, y: 650, z: game_text_z, text: "DIFFICULTY: #{state.difficulty.upcase}", **large_white_typeset }
  end

  def render_menu
    return unless state.scene == :menu
    render_overlay

    outputs.labels << { x: 640, y: 700, z: menu_text_z, text: "Flappy Dragon", size_enum: 50, alignment_enum: 1, **white }
    outputs.labels << { x: 640, y: 500, z: menu_text_z, text: "Instructions: Press Spacebar to flap. Don't die.", size_enum: 4, alignment_enum: 1, **white }
    outputs.labels << { x: 430, y: 430, z: menu_text_z, text: "[Tab]    Change difficulty", size_enum: 4, alignment_enum: 0, **white }
    outputs.labels << { x: 430, y: 400, z: menu_text_z, text: "[Enter]  Start at New Difficulty ", size_enum: 4, alignment_enum: 0, **white }
    outputs.labels << { x: 430, y: 370, z: menu_text_z, text: "[Escape] Cancel/Resume ", size_enum: 4, alignment_enum: 0, **white }
    outputs.labels << { x: 640, y: 300, z: menu_text_z, text: "(mouse, touch, and game controllers work, too!) ", size_enum: 4, alignment_enum: 1, **white }
    outputs.labels << { x: 640, y: 200, z: menu_text_z, text: "Difficulty: #{state.new_difficulty.capitalize}", size_enum: 4, alignment_enum: 1, **white }

    outputs.labels << { x: 10, y: 100, z: menu_text_z, text: "Code:   @amirrajan",     **white }
    outputs.labels << { x: 10, y:  80, z: menu_text_z, text: "Art:    @mobypixel",     **white }
    outputs.labels << { x: 10, y:  60, z: menu_text_z, text: "Music:  @mobypixel",     **white }
    outputs.labels << { x: 10, y:  40, z: menu_text_z, text: "Engine: DragonRuby GTK", **white }
  end

  def render_overlay
    overlay_rect = grid.rect.scale_rect(1.5, 0, 0)
    outputs.primitives << { x: overlay_rect.x - overlay_rect.w,
                            y: overlay_rect.y - overlay_rect.h,
                            w: overlay_rect.w * 4,
                            h: overlay_rect.h * 2,
                            z: menu_overlay_z,
                            r: 0, g: 0, b: 0, a: 230 }.solid!
  end

  def render_game
    outputs.background_color = [0, 0, 0]
    render_game_over
    render_background
    render_walls
    render_dragon
    render_flash
  end

  def render_game_over
    return unless state.scene == :game
    outputs.labels << { x: 638, y: 358, text: score_text,     z: game_text_z - 1,  size_enum: 20, alignment_enum: 1 }
    outputs.labels << { x: 635, y: 360, text: score_text,     z: game_text_z,  size_enum: 20, alignment_enum: 1, r: 255, g: 255, b: 255 }
    outputs.labels << { x: 638, y: 428, text: countdown_text, z: game_text_z - 1,  size_enum: 20, alignment_enum: 1 }
    outputs.labels << { x: 635, y: 430, text: countdown_text, z: game_text_z,  size_enum: 20, alignment_enum: 1, r: 255, g: 255, b: 255 }
  end

  def render_background
    scroll_point_at   = Kernel.tick_count
    scroll_point_at   = state.scene_at if state.scene == :menu
    scroll_point_at   = state.death_at if state.countdown > 0
    scroll_point_at ||= 0

    outputs.sprites << { x: -640, y: -360, z: background_z, w: 1280 * 2, h: 720 * 2, path: 'sprites/background.png' }
    outputs.sprites << scrolling_background(scroll_point_at, 'sprites/parallax_back.png',   0.25, 1)
    outputs.sprites << scrolling_background(scroll_point_at, 'sprites/parallax_middle.png', 0.50, 50)
    outputs.sprites << scrolling_background(scroll_point_at, 'sprites/parallax_front.png',  1.00, 100, -80)
  end

  def scrolling_background at, path, rate, z, y = 0
    rate *= 2
    w = 1440 * 2
    h =  720 * 2
    [
      { x: w - at.*(rate) % w - w.half.half, y: y * 2 - 360, z: background_z + z, w: w, h: h, path: path },
      { x: 0 - at.*(rate) % w - w.half.half, y: y * 2 - 360, z: background_z + z, w: w, h: h, path: path },
    ]
  end

  def render_walls
    state.walls.each do |w|
      w.top_section = { x: w.x,
                        y: w.bottom_height - 720,
                        z: -120,
                        w: 100,
                        h: 720,
                        path: 'sprites/wall.png',
                        angle: 180 }

      w.bottom_section = { x: w.x,
                           y: w.top_y,
                           z: -120,
                           w: 100,
                           h: 720,
                           path: 'sprites/wallbottom.png',
                           angle: 0}
      w.sprites = [
        model_for(w.top_section),
        model_for(w.bottom_section)
      ]
    end

    outputs.sprites << state.walls.find_all { |w| w.x >= state.x }.reverse.map(&:sprites)
    outputs.sprites << state.walls.find_all { |w| w.x <  state.x }.map(&:sprites)
  end

  def model_for wall
    ratio = (wall.x - state.x_starting_point).abs.fdiv(2560 + state.x_starting_point)
    z_ratio = ratio ** 2
    z_offset = (2560 * 2) * z_ratio
    x_offset = z_offset * 0.25

    if wall.x < state.x
      x_offset *= -1
    end

    distance_from_background_to_flappy = (background_z - flappy_sprite_z).abs
    distance_to_front = z_offset

    if -z_offset < background_z + 100 + wall.w * 2
      a = 0
    else
      percentage_to_front = distance_to_front / distance_from_background_to_flappy
      a = 255 * (1 - percentage_to_front)
    end


    back  = { x:     wall.x + x_offset,
              y:     wall.y,
              z:     wall.z - wall.w.half - z_offset,
              a:     a,
              w:     wall.w,
              h:     wall.h,
              path:  wall.path,
              angle: wall.angle }
    front = { x:     wall.x + x_offset,
              y:     wall.y,
              z:     wall.z + wall.w.half - z_offset,
              a:     a,
              w:     wall.w,
              h:     wall.h,
              path:  wall.path,
              angle: wall.angle }
    left  = { x:     wall.x - wall.w.half + x_offset,
              y:     wall.y,
              z:     wall.z - z_offset,
              a:     a,
              angle_y: 90,
              w:     wall.w,
              h:     wall.h,
              path:  wall.path,
              angle: wall.angle }
    right = { x:     wall.x + wall.w.half + x_offset,
              y:     wall.y,
              z:     wall.z - z_offset,
              a:     a,
              angle_y: 90,
              w:     wall.w,
              h:     wall.h,
              path:  wall.path,
              angle: wall.angle }
    if    (wall.x - wall.w - state.x).abs < 200
      [back, left, right, front]
    elsif wall.x < state.x
      [back, left, front, right]
    else
      [back, right, front, left]
    end
  end

  def render_dragon
    state.show_death = true if state.countdown == 3.seconds

    if state.show_death == false || !state.death_at
      animation_index = state.flapped_at.frame_index 6, 2, false if state.flapped_at
      sprite_name = "sprites/dragon_fly#{animation_index.or(0) + 1}.png"
      state.dragon_sprite = { x: state.x, y: state.y, z: state.z, w: 100, h: 80, path: sprite_name, angle: state.dy * 1.2 }
    else
      sprite_name = "sprites/dragon_die.png"
      state.dragon_sprite = { x: state.x, y: state.y, z: state.z, w: 100, h: 80, path: sprite_name, angle: state.dy * 1.2 }
      sprite_changed_elapsed    = state.death_at.elapsed_time - 1.seconds
      state.dragon_sprite.angle += (sprite_changed_elapsed ** 1.3) * state.death_fall_direction * -1
      state.dragon_sprite.x     += (sprite_changed_elapsed ** 1.2) * state.death_fall_direction
      state.dragon_sprite.y     += (sprite_changed_elapsed * 14 - sprite_changed_elapsed ** 1.6)
      state.z     += 0.3
    end

    outputs.sprites << state.dragon_sprite
  end

  def render_flash
    return unless state.flash_at

    outputs.primitives << { **grid.rect.to_hash,
                            **white,
                            z: flash_z,
                            a: 255 * state.flash_at.ease(20, :flip) }.solid!

    state.flash_at = 0 if state.flash_at.elapsed_time > 20
  end

  def calc
    return unless state.scene == :game
    reset_game if state.countdown == 1
    state.countdown -= 1 and return if state.countdown > 0
    calc_walls
    calc_flap
    calc_game_over
  end

  def calc_walls
    state.walls.each { |w| w.x -= 8 }

    walls_count_before_removal = state.walls.length

    state.walls.reject! { |w| w.x < -2560 + state.x_starting_point }

    state.score += 1 if state.walls.count < walls_count_before_removal

    state.wall_countdown -= 1 and return if state.wall_countdown > 0

    state.walls << state.new_entity(:wall) do |w|
      w.x             = 2560 + state.x_starting_point
      w.opening       = grid.top
                            .randomize(:ratio)
                            .greater(200)
                            .lesser(520)
      w.opening -= w.opening * 0.5
      w.bottom_height = w.opening - state.wall_gap_size
      w.top_y         = w.opening + state.wall_gap_size
    end

    state.wall_countdown = state.wall_countdown_length
  end

  def calc_flap
    state.y += state.dy
    state.dy = state.dy.lesser state.flap_power
    state.dy -= state.gravity
    return if state.y < state.ceiling
    state.y  = state.ceiling
    state.dy = state.dy.lesser state.ceiling_flap_power
  end

  def calc_game_over
    return unless game_over?

    state.death_at = Kernel.tick_count
    state.death_from = state.walls.first
    state.death_fall_direction = -1
    state.death_fall_direction =  1 if state.x > state.death_from.x
    outputs.sounds << "sounds/hit-sound.wav"
    begin_countdown
  end

  def process_inputs
    process_inputs_menu
    process_inputs_game
  end

  def process_inputs_menu
    return unless state.scene == :menu

    changediff = inputs.keyboard.key_down.tab || inputs.controller_one.key_down.select
    if inputs.mouse.click
      p = inputs.mouse.click.point
      if (p.y >= 165) && (p.y < 200) && (p.x >= 500) && (p.x < 800)
        changediff = true
      end
    end

    if changediff
      case state.new_difficulty
      when :easy
        state.new_difficulty = :normal
      when :normal
        state.new_difficulty = :hard
      when :hard
        state.new_difficulty = :flappy
      when :flappy
        state.new_difficulty = :easy
      end
    end

    if inputs.keyboard.key_down.enter || inputs.controller_one.key_down.start || inputs.controller_one.key_down.a
      state.difficulty = state.new_difficulty
      change_to_scene :game
      reset_game false
      state.hi_score = 0
      begin_countdown
    end

    if inputs.keyboard.key_down.escape || (inputs.mouse.click && !changediff) || inputs.controller_one.key_down.b
      state.new_difficulty = state.difficulty
      change_to_scene :game
    end
  end

  def process_inputs_game
    return unless state.scene == :game

    clicked_menu = false
    if inputs.mouse.click
      p = inputs.mouse.click.point
      clicked_menu = (p.y >= 620) && (p.x < 275)
    end

    if clicked_menu || inputs.keyboard.key_down.escape || inputs.keyboard.key_down.enter || inputs.controller_one.key_down.start
      change_to_scene :menu
    elsif (inputs.mouse.down || inputs.mouse.click || inputs.keyboard.key_down.space || inputs.controller_one.key_down.a) && state.countdown == 0
      state.dy = 0
      state.dy += state.flap_power
      state.flapped_at = Kernel.tick_count
      outputs.sounds << "sounds/fly-sound.wav"
    end
  end

  def white
    { r: 255, g: 255, b: 255 }
  end

  def large_white_typeset
    { size_enum: 5, alignment_enum: 0, r: 255, g: 255, b: 255 }
  end

  def at_beginning?
    state.walls.count == 0
  end

  def dragon_collision_box
    { x: state.dragon_sprite.x,
      y: state.dragon_sprite.y,
      w: state.dragon_sprite.w,
      h: state.dragon_sprite.h }
         .scale_rect(1.0 - collision_forgiveness, 0.5, 0.5)
         .rect_shift_right(10)
         .rect_shift_up(state.dy * 2)
  end

  def game_over?
    return true if state.y <= 0.-(500 * collision_forgiveness) && !at_beginning?

    state.walls
         .find_all { |w| w.top_section && w.bottom_section }
         .flat_map { |w| [w.top_section, w.bottom_section] }
         .any?     { |s| s.intersect_rect?(dragon_collision_box) }
  end

  def collision_forgiveness
    case state.difficulty
    when :easy
      0.9
    when :normal
      0.7
    when :hard
      0.5
    when :flappy
      0.3
    else
      0.9
    end
  end

  def countdown_text
    state.countdown ||= -1
    return ""          if state.countdown == 0
    return "GO!"       if state.countdown.idiv(60) == 0
    return "GAME OVER" if state.death_at
    return "READY?"
  end

  def begin_countdown
    state.countdown = 4.seconds
  end

  def score_text
    return ""                        unless state.countdown > 1.seconds
    return ""                        unless state.death_at
    return "SCORE: 0 (LOL)"          if state.score == 0
    return "HI SCORE: #{state.score}" if state.score == state.hi_score
    return "SCORE: #{state.score}"
  end

  def reset_game set_flash = true
    state.flash_at = Kernel.tick_count if set_flash
    state.walls = []
    state.y = 500
    state.x =  state.x_starting_point
    state.z = flappy_sprite_z
    state.dy = 0
    state.hi_score = state.hi_score.greater(state.score)
    state.score = 0
    state.wall_countdown = state.wall_countdown_length.fdiv(2)
    state.show_death = false
    state.death_at = nil
  end

  def change_to_scene scene
    state.scene = scene
    state.scene_at = Kernel.tick_count
    inputs.keyboard.clear
    inputs.controller_one.clear
  end
end

$flappy_dragon = FlappyDragon.new

def tick_game args
  $flappy_dragon.grid = args.grid
  $flappy_dragon.inputs = args.inputs
  $flappy_dragon.state = args.state
  $flappy_dragon.outputs = args.outputs
  $flappy_dragon.tick
end

$gtk.reset

Cubeworld main.rb link

# ./samples/14_vr/08_cubeworld_vr/app/main.rb
require 'app/tick.rb'

def tick args
  args.gtk.start_server! port: 9001, enable_in_prod: true
  $game ||= Game.new
  $game.args = args
  $game.tick
end

Cubeworld tick.rb link

# ./samples/14_vr/08_cubeworld_vr/app/tick.rb
class Game
  include MatrixFunctions

  attr_gtk

  def cube x:, y:, z:, angle_x:, angle_y:, angle_z:;
    combined = mul (rotate_x angle_x),
                   (rotate_y angle_y),
                   (rotate_z angle_z),
                   (translate x, y, z)

    face_1 = mul_triangles state.baseline_cube.face_1, combined
    face_2 = mul_triangles state.baseline_cube.face_2, combined
    face_3 = mul_triangles state.baseline_cube.face_3, combined
    face_4 = mul_triangles state.baseline_cube.face_4, combined
    face_5 = mul_triangles state.baseline_cube.face_5, combined
    face_6 = mul_triangles state.baseline_cube.face_6, combined

    [
      face_1,
      face_2,
      face_3,
      face_4,
      face_5,
      face_6
    ]
  end

  def random_point
    r = { xr: 2.randomize(:ratio) - 1,
          yr: 2.randomize(:ratio) - 1,
          zr: 2.randomize(:ratio) - 1 }
    if (r.xr ** 2 + r.yr ** 2 + r.zr ** 2) > 1.0
      return random_point
    else
      return r
    end
  end

  def random_cube_attributes
    state.cube_count.map_with_index do |i|
      point_on_sphere = random_point
      radius = rand * 10 + 3
      {
        x: point_on_sphere.xr * radius,
        y: point_on_sphere.yr * radius,
        z: 6.4 + point_on_sphere.zr * radius
      }
    end
  end

  def defaults
    state.cube_count ||= 1
    state.cube_attributes ||= random_cube_attributes
    if !state.baseline_cube
      state.baseline_cube = {
        face_1: [
          [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
          [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
        ],
        face_2: [
          [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
          [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
        ],
        face_3: [
          [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
          [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
        ],
        face_4: [
          [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
          [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
        ],
        face_5: [
          [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
          [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
        ],
        face_6: [
          [vec4(0, 0, 0, 1),   vec4(0.5, 0, 0, 1),   vec4(0, 0.5, 0, 1)],
          [vec4(0.5, 0, 0, 1), vec4(0.5, 0.5, 0, 1), vec4(0, 0.5, 0, 1)]
        ]
      }

      state.baseline_cube.face_1 = mul_triangles state.baseline_cube.face_1,
                                                 (translate -0.25, -0.25, 0),
                                                 (translate  0, 0, 0.25)

      state.baseline_cube.face_2 = mul_triangles state.baseline_cube.face_2,
                                                 (translate -0.25, -0.25, 0),
                                                 (translate  0, 0, -0.25)

      state.baseline_cube.face_3 = mul_triangles state.baseline_cube.face_3,
                                                 (translate -0.25, -0.25, 0),
                                                 (rotate_y 90),
                                                 (translate -0.25,  0, 0)

      state.baseline_cube.face_4 = mul_triangles state.baseline_cube.face_4,
                                                 (translate -0.25, -0.25, 0),
                                                 (rotate_y 90),
                                                 (translate  0.25,  0, 0)

      state.baseline_cube.face_5 = mul_triangles state.baseline_cube.face_5,
                                                 (translate -0.25, -0.25, 0),
                                                 (rotate_x 90),
                                                 (translate  0,  0.25, 0)

      state.baseline_cube.face_6 = mul_triangles state.baseline_cube.face_6,
                                                 (translate -0.25, -0.25, 0),
                                                 (rotate_x 90),
                                                 (translate  0,  -0.25, 0)
    end
  end

  def tick
    args.grid.origin_center!
    defaults

    if inputs.controller_one.key_down.a
      state.cube_count += 1
      state.cube_attributes = random_cube_attributes
    elsif inputs.controller_one.key_down.b
      state.cube_count -= 1 if state.cube_count > 1
      state.cube_attributes = random_cube_attributes
    end

    state.cube_attributes.each do |c|
      render_cube (cube x: c.x, y: c.y, z: c.z,
                        angle_x: Kernel.tick_count,
                        angle_y: Kernel.tick_count,
                        angle_z: Kernel.tick_count)
    end

    args.outputs.background_color = [255, 255, 255]
    framerate_primitives = args.gtk.current_framerate_primitives
    framerate_primitives.find { |p| p.text }.each { |p| p.z = 1 }
    framerate_primitives[-1].text = "cube count: #{state.cube_count} (#{state.cube_count * 12} triangles)"
    args.outputs.primitives << framerate_primitives
  end

  def translate dx, dy, dz
    mat4 1, 0, 0, dx,
         0, 1, 0, dy,
         0, 0, 1, dz,
         0, 0, 0,  1
  end

  def rotate_x angle_d
    cos_t = Math.cos angle_d.to_radians
    sin_t = Math.sin angle_d.to_radians
    mat4  1,     0,      0, 0,
          0, cos_t, -sin_t, 0,
          0, sin_t,  cos_t, 0,
          0,     0,      0, 1
  end

  def rotate_y angle_d
    cos_t = Math.cos angle_d.to_radians
    sin_t = Math.sin angle_d.to_radians
    mat4  cos_t,  0, sin_t, 0,
          0,      1, 0,     0,
          -sin_t, 0, cos_t, 0,
          0,      0, 0,     1
  end

  def rotate_z angle_d
    cos_t = Math.cos angle_d.to_radians
    sin_t = Math.sin angle_d.to_radians
    mat4 cos_t, -sin_t, 0, 0,
         sin_t,  cos_t, 0, 0,
         0,      0,     1, 0,
         0,      0,     0, 1
  end

  def mul_triangles model, *mul_def
    model.map do |vecs|
      vecs.map do |vec|
        vec = mul vec, *mul_def
      end
    end
  end

  def render_cube cube
    render_face cube[0]
    render_face cube[1]
    render_face cube[2]
    render_face cube[3]
    render_face cube[4]
    render_face cube[5]
  end

  def render_face face
    triangle_1 = face[0]
    args.outputs.sprites << {
      x:  triangle_1[0].x * 100,   y: triangle_1[0].y * 100,  z: triangle_1[0].z * 100,
      x2: triangle_1[1].x * 100,  y2: triangle_1[1].y * 100, z2: triangle_1[1].z * 100,
      x3: triangle_1[2].x * 100,  y3: triangle_1[2].y * 100, z3: triangle_1[2].z * 100,
      source_x:   0, source_y:   0,
      source_x2: 80, source_y2:  0,
      source_x3:  0, source_y3: 80,
      path: 'sprites/square/blue.png'
    }

    triangle_2 = face[1]
    args.outputs.sprites << {
      x:  triangle_2[0].x * 100,   y: triangle_2[0].y * 100,  z: triangle_2[0].z * 100,
      x2: triangle_2[1].x * 100,  y2: triangle_2[1].y * 100, z2: triangle_2[1].z * 100,
      x3: triangle_2[2].x * 100,  y3: triangle_2[2].y * 100, z3: triangle_2[2].z * 100,
      source_x:  80, source_y:   0,
      source_x2: 80, source_y2: 80,
      source_x3:  0, source_y3: 80,
      path: 'sprites/square/blue.png'
    }
  end
end

Genre 3d link

3d Cube - main.rb link

# ./samples/99_genre_3d/01_3d_cube/app/main.rb
STARTX             = 0.0
STARTY             = 0.0
ENDY               = 20.0
ENDX               = 20.0
SPINPOINT          = 10
SPINDURATION       = 400
POINTSIZE          = 8
BOXDEPTH           = 40
YAW                = 1
DISTANCE           = 10

def tick args
  args.outputs.background_color = [0, 0, 0]
  a = Math.sin(Kernel.tick_count / SPINDURATION) * Math.tan(Kernel.tick_count / SPINDURATION)
  s = Math.sin(a)
  c = Math.cos(a)
  x = STARTX
  y = STARTY
  offset_x = (1280 - (ENDX - STARTX)) / 2
  offset_y =  (360 - (ENDY - STARTY)) / 2

  srand(1)
  while y < ENDY do
    while x < ENDX do
      if (y == STARTY ||
          y == (ENDY / 0.5) * 2 ||
          y == (ENDY / 0.5) * 2 + 0.5 ||
          y == ENDY - 0.5 ||
          x == STARTX ||
          x == ENDX - 0.5)
        z = rand(BOXDEPTH)
        z *= Math.sin(a / 2)
        x -= SPINPOINT
        u = (x * c) - (z * s)
        v = (x * s) + (z * c)
        k = DISTANCE.fdiv(100) + (v / 500 * YAW)
        u = u / k
        v = y / k
        w = POINTSIZE / 10 / k
        args.outputs.sprites << { x: offset_x + u - w, y: offset_y + v - w, w: w, h: w, path: 'sprites/square-blue.png'}
        x += SPINPOINT
      end
      x += 0.5
    end
    y += 0.5
    x = STARTX
  end
end

$gtk.reset

Wireframe - main.rb link

# ./samples/99_genre_3d/02_wireframe/app/main.rb
def tick args
  args.state.model   ||= Object3D.new('data/shuttle.off')
  args.state.mtx     ||= rotate3D(0, 0, 0)
  args.state.inv_mtx ||= rotate3D(0, 0, 0)
  delta_mtx          = rotate3D(args.inputs.up_down * 0.01, input_roll(args) * 0.01, args.inputs.left_right * 0.01)
  args.outputs.lines << args.state.model.edges
  args.state.model.fast_3x3_transform! args.state.inv_mtx
  args.state.inv_mtx = mtx_mul(delta_mtx.transpose, args.state.inv_mtx)
  args.state.mtx     = mtx_mul(args.state.mtx, delta_mtx)
  args.state.model.fast_3x3_transform! args.state.mtx
  args.outputs.background_color = [0, 0, 0]
  args.outputs.debug << args.gtk.framerate_diagnostics_primitives
end

def input_roll args
  roll = 0
  roll += 1 if args.inputs.keyboard.e
  roll -= 1 if args.inputs.keyboard.q
  roll
end

def rotate3D(theta_x = 0.1, theta_y = 0.1, theta_z = 0.1)
  c_x, s_x = Math.cos(theta_x), Math.sin(theta_x)
  c_y, s_y = Math.cos(theta_y), Math.sin(theta_y)
  c_z, s_z = Math.cos(theta_z), Math.sin(theta_z)
  rot_x    = [[1, 0, 0], [0, c_x, -s_x], [0, s_x, c_x]]
  rot_y    = [[c_y, 0, s_y], [0, 1, 0], [-s_y, 0, c_y]]
  rot_z    = [[c_z, -s_z, 0], [s_z, c_z, 0], [0, 0, 1]]
  mtx_mul(mtx_mul(rot_x, rot_y), rot_z)
end

def mtx_mul(a, b)
  is = (0...a.length)
  js = (0...b[0].length)
  ks = (0...b.length)
  is.map do |i|
    js.map do |j|
      ks.map do |k|
        a[i][k] * b[k][j]
      end.reduce(&:plus)
    end
  end
end

class Object3D
  attr_reader :vert_count, :face_count, :edge_count, :verts, :faces, :edges

  def initialize(path)
    @vert_count = 0
    @face_count = 0
    @edge_count = 0
    @verts      = []
    @faces      = []
    @edges      = []
    _init_from_file path
  end

  def _init_from_file path
    file_lines = $gtk.read_file(path).split("\n")
                     .reject { |line| line.start_with?('#') || line.split(' ').length == 0 } # Strip out simple comments and blank lines
                     .map { |line| line.split('#')[0] } # Strip out end of line comments
                     .map { |line| line.split(' ') } # Tokenize by splitting on whitespace
    raise "OFF file did not start with OFF." if file_lines.shift != ["OFF"] # OFF meshes are supposed to begin with "OFF" as the first line.
    raise "<NVertices NFaces NEdges> line malformed" if file_lines[0].length != 3 # The second line needs to have 3 numbers. Raise an error if it doesn't.
    @vert_count, @face_count, @edge_count = file_lines.shift&.map(&:to_i) # Update the counts
    # Only the vertex and face counts need to be accurate. Raise an error if they are inaccurate.
    raise "Incorrect number of vertices and/or faces (Parsed VFE header: #{@vert_count} #{@face_count} #{@edge_count})" if file_lines.length != @vert_count + @face_count
    # Grab all the lines describing vertices.
    vert_lines = file_lines[0, @vert_count]
    # Grab all the lines describing faces.
    face_lines = file_lines[@vert_count, @face_count]
    # Create all the vertices
    @verts = vert_lines.map_with_index { |line, id| Vertex.new(line, id) }
    # Create all the faces
    @faces = face_lines.map { |line| Face.new(line, @verts) }
    # Create all the edges
    @edges = @faces.flat_map(&:edges).uniq do |edge|
      sorted = edge.sorted
      [sorted.point_a, sorted.point_b]
    end
  end

  def fast_3x3_transform! mtx
    @verts.each { |vert| vert.fast_3x3_transform! mtx }
  end
end

class Face

  attr_reader :verts, :edges

  def initialize(data, verts)
    vert_count = data[0].to_i
    vert_ids   = data[1, vert_count].map(&:to_i)
    @verts     = vert_ids.map { |i| verts[i] }
    @edges     = []
    (0...vert_count).each { |i| @edges[i] = Edge.new(verts[vert_ids[i - 1]], verts[vert_ids[i]]) }
    @edges.rotate! 1
  end
end

class Edge
  attr_reader :point_a, :point_b

  def initialize(point_a, point_b)
    @point_a = point_a
    @point_b = point_b
  end

  def sorted
    @point_a.id < @point_b.id ? self : Edge.new(@point_b, @point_a)
  end

  def draw_override ffi
    ffi.draw_line(@point_a.render_x, @point_a.render_y, @point_b.render_x, @point_b.render_y, 255, 0, 0, 128)
    ffi.draw_line(@point_a.render_x+1, @point_a.render_y, @point_b.render_x+1, @point_b.render_y, 255, 0, 0, 128)
    ffi.draw_line(@point_a.render_x, @point_a.render_y+1, @point_b.render_x, @point_b.render_y+1, 255, 0, 0, 128)
    ffi.draw_line(@point_a.render_x+1, @point_a.render_y+1, @point_b.render_x+1, @point_b.render_y+1, 255, 0, 0, 128)
  end

  def primitive_marker
    :line
  end
end

class Vertex
  attr_accessor :x, :y, :z, :id

  def initialize(data, id)
    @x  = data[0].to_f
    @y  = data[1].to_f
    @z  = data[2].to_f
    @id = id
  end

  def fast_3x3_transform! mtx
    _x, _y, _z = @x, @y, @z
    @x         = mtx[0][0] * _x + mtx[0][1] * _y + mtx[0][2] * _z
    @y         = mtx[1][0] * _x + mtx[1][1] * _y + mtx[1][2] * _z
    @z         = mtx[2][0] * _x + mtx[2][1] * _y + mtx[2][2] * _z
  end

  def render_x
    @x * (10 / (5 - @y)) * 170 + 640
  end

  def render_y
    @z * (10 / (5 - @y)) * 170 + 360
  end
end

Wireframe - Data - what-is-this.txt link

# ./samples/99_genre_3d/02_wireframe/data/what-is-this.txt
https://en.wikipedia.org/wiki/OFF_(file_format)

Yaw Pitch Roll - main.rb link

# ./samples/99_genre_3d/03_yaw_pitch_roll/app/main.rb
class Game
  include MatrixFunctions

  attr_gtk

  def tick
    defaults
    render
    input
  end

  def player_ship
    [
      # engine back
      (vec4  -1,  -1,  1,  0),
      (vec4  -1,   1,  1,  0),

      (vec4  -1,   1,  1,  0),
      (vec4   1,   1,  1,  0),

      (vec4   1,   1,  1,  0),
      (vec4   1,  -1,  1,  0),

      (vec4   1,  -1,  1,  0),
      (vec4  -1,  -1,  1,  0),

      # engine front
      (vec4  -1,  -1,  -1,  0),
      (vec4  -1,   1,  -1,  0),

      (vec4  -1,   1,  -1,  0),
      (vec4   1,   1,  -1,  0),

      (vec4   1,   1,  -1,  0),
      (vec4   1,  -1,  -1,  0),

      (vec4   1,  -1,  -1,  0),
      (vec4  -1,  -1,  -1,  0),

      # engine left
      (vec4  -1,   -1,  -1,  0),
      (vec4  -1,   -1,   1,  0),

      (vec4  -1,   -1,   1,  0),
      (vec4  -1,    1,   1,  0),

      (vec4  -1,    1,   1,  0),
      (vec4  -1,    1,  -1,  0),

      (vec4  -1,    1,  -1,  0),
      (vec4  -1,   -1,  -1,  0),

      # engine right
      (vec4   1,   -1,  -1,  0),
      (vec4   1,   -1,   1,  0),

      (vec4   1,   -1,   1,  0),
      (vec4   1,    1,   1,  0),

      (vec4   1,    1,   1,  0),
      (vec4   1,    1,  -1,  0),

      (vec4   1,    1,  -1,  0),
      (vec4   1,   -1,  -1,  0),

      # top front of engine to front of ship
      (vec4   1,    1,  1,  0),
      (vec4   0,   -1,  9,  0),

      (vec4   0,   -1,  9,  0),
      (vec4  -1,    1,  1,  0),

      # bottom front of engine
      (vec4   1,   -1,  1,  0),
      (vec4   0,   -1,  9,  0),

      (vec4  -1,   -1,  1,  0),
      (vec4   0,   -1,  9,  0),

      # right wing
      # front of wing
      (vec4  1,  0.10,   1,  0),
      (vec4  9,  0.10,  -1,  0),

      (vec4   9,  0.10,  -1,  0),
      (vec4  10,  0.10,  -2,  0),

      # back of wing
      (vec4  1,  0.10,  -1,  0),
      (vec4  9,  0.10,  -1,  0),

      (vec4  10,  0.10,  -2,  0),
      (vec4   8,  0.10,  -1,  0),

      # front of wing
      (vec4  1,  -0.10,   1,  0),
      (vec4  9,  -0.10,  -1,  0),

      (vec4   9,  -0.10,  -1,  0),
      (vec4  10,  -0.10,  -2,  0),

      # back of wing
      (vec4  1,  -0.10,  -1,  0),
      (vec4  9,  -0.10,  -1,  0),

      (vec4  10,  -0.10,  -2,  0),
      (vec4   8,  -0.10,  -1,  0),

      # left wing
      # front of wing
      (vec4  -1,  0.10,   1,  0),
      (vec4  -9,  0.10,  -1,  0),

      (vec4  -9,  0.10,  -1,  0),
      (vec4  -10,  0.10,  -2,  0),

      # back of wing
      (vec4  -1,  0.10,  -1,  0),
      (vec4  -9,  0.10,  -1,  0),

      (vec4  -10,  0.10,  -2,  0),
      (vec4  -8,  0.10,  -1,  0),

      # front of wing
      (vec4  -1,  -0.10,   1,  0),
      (vec4  -9,  -0.10,  -1,  0),

      (vec4  -9,  -0.10,  -1,  0),
      (vec4  -10,  -0.10,  -2,  0),

      # back of wing
      (vec4  -1,  -0.10,  -1,  0),
      (vec4  -9,  -0.10,  -1,  0),
      (vec4  -10,  -0.10,  -2,  0),
      (vec4   -8,  -0.10,  -1,  0),

      # left fin
      # top
      (vec4  -1,  0.10,  1,  0),
      (vec4  -1,  3,  -3,  0),

      (vec4  -1,  0.10,  -1,  0),
      (vec4  -1,  3,  -3,  0),

      (vec4  -1.1,  0.10,  1,  0),
      (vec4  -1.1,  3,  -3,  0),

      (vec4  -1.1,  0.10,  -1,  0),
      (vec4  -1.1,  3,  -3,  0),

      # bottom
      (vec4  -1,  -0.10,  1,  0),
      (vec4  -1,  -2,  -2,  0),

      (vec4  -1,  -0.10,  -1,  0),
      (vec4  -1,  -2,  -2,  0),

      (vec4  -1.1,  -0.10,  1,  0),
      (vec4  -1.1,  -2,  -2,  0),

      (vec4  -1.1,  -0.10,  -1,  0),
      (vec4  -1.1,  -2,  -2,  0),

      # right fin
      (vec4   1,  0.10,  1,  0),
      (vec4   1,  3,  -3,  0),

      (vec4   1,  0.10,  -1,  0),
      (vec4   1,  3,  -3,  0),

      (vec4   1.1,  0.10,  1,  0),
      (vec4   1.1,  3,  -3,  0),

      (vec4   1.1,  0.10,  -1,  0),
      (vec4   1.1,  3,  -3,  0),

      # bottom
      (vec4   1,  -0.10,  1,  0),
      (vec4   1,  -2,  -2,  0),

      (vec4   1,  -0.10,  -1,  0),
      (vec4   1,  -2,  -2,  0),

      (vec4   1.1,  -0.10,  1,  0),
      (vec4   1.1,  -2,  -2,  0),

      (vec4   1.1,  -0.10,  -1,  0),
      (vec4   1.1,  -2,  -2,  0),
    ]
  end

  def defaults
    state.points ||= player_ship
    state.shifted_points ||= state.points.map { |point| point }

    state.scale   ||= 1
    state.angle_x ||= 0
    state.angle_y ||= 0
    state.angle_z ||= 0
  end

  def angle_z_matrix degrees
    cos_t = Math.cos degrees.to_radians
    sin_t = Math.sin degrees.to_radians
    (mat4 cos_t, -sin_t, 0, 0,
          sin_t,  cos_t, 0, 0,
          0,      0,     1, 0,
          0,      0,     0, 1)
  end

  def angle_y_matrix degrees
    cos_t = Math.cos degrees.to_radians
    sin_t = Math.sin degrees.to_radians
    (mat4  cos_t,  0, sin_t, 0,
           0,      1, 0,     0,
           -sin_t, 0, cos_t, 0,
           0,      0, 0,     1)
  end

  def angle_x_matrix degrees
    cos_t = Math.cos degrees.to_radians
    sin_t = Math.sin degrees.to_radians
    (mat4  1,     0,      0, 0,
           0, cos_t, -sin_t, 0,
           0, sin_t,  cos_t, 0,
           0,     0,      0, 1)
  end

  def scale_matrix factor
    (mat4 factor,      0,      0, 0,
          0,      factor,      0, 0,
          0,           0, factor, 0,
          0,           0,      0, 1)
  end

  def input
    if (inputs.keyboard.shift && inputs.keyboard.p)
      state.scale -= 0.1
    elsif  inputs.keyboard.p
      state.scale += 0.1
    end

    if inputs.mouse.wheel
      state.scale += inputs.mouse.wheel.y
    end

    state.scale = state.scale.clamp(0.1, 1000)

    if (inputs.keyboard.shift && inputs.keyboard.y) || inputs.keyboard.right
      state.angle_y += 1
    elsif (inputs.keyboard.y) || inputs.keyboard.left
      state.angle_y -= 1
    end

    if (inputs.keyboard.shift && inputs.keyboard.x) || inputs.keyboard.down
      state.angle_x -= 1
    elsif (inputs.keyboard.x || inputs.keyboard.up)
      state.angle_x += 1
    end

    if inputs.keyboard.shift && inputs.keyboard.z
      state.angle_z += 1
    elsif inputs.keyboard.z
      state.angle_z -= 1
    end

    if inputs.keyboard.zero
      state.angle_x = 0
      state.angle_y = 0
      state.angle_z = 0
    end

    angle_x = state.angle_x
    angle_y = state.angle_y
    angle_z = state.angle_z
    scale   = state.scale

    s_matrix = scale_matrix state.scale
    x_matrix = angle_z_matrix angle_z
    y_matrix = angle_y_matrix angle_y
    z_matrix = angle_x_matrix angle_x

    state.shifted_points = state.points.map do |point|
      (mul point, y_matrix, x_matrix, z_matrix, s_matrix).merge(original: point)
    end
  end

  def thick_line line
    [
      line.merge(y: line.y - 1, y2: line.y2 - 1, r: 0, g: 0, b: 0),
      line.merge(x: line.x - 1, x2: line.x2 - 1, r: 0, g: 0, b: 0),
      line.merge(x: line.x - 0, x2: line.x2 - 0, r: 0, g: 0, b: 0),
      line.merge(y: line.y + 1, y2: line.y2 + 1, r: 0, g: 0, b: 0),
      line.merge(x: line.x + 1, x2: line.x2 + 1, r: 0, g: 0, b: 0)
    ]
  end

  def render
    outputs.lines << state.shifted_points.each_slice(2).map do |(p1, p2)|
      perc = 0
      thick_line({ x:  p1.x.*(10) + 640, y:  p1.y.*(10) + 320,
                   x2: p2.x.*(10) + 640, y2: p2.y.*(10) + 320,
                   r: 255 * perc,
                   g: 255 * perc,
                   b: 255 * perc })
    end

    outputs.labels << [ 10, 700, "angle_x: #{state.angle_x.to_sf}", 0]
    outputs.labels << [ 10, 670, "x, shift+x", 0]

    outputs.labels << [210, 700, "angle_y: #{state.angle_y.to_sf}", 0]
    outputs.labels << [210, 670, "y, shift+y", 0]

    outputs.labels << [410, 700, "angle_z: #{state.angle_z.to_sf}", 0]
    outputs.labels << [410, 670, "z, shift+z", 0]

    outputs.labels << [610, 700, "scale: #{state.scale.to_sf}", 0]
    outputs.labels << [610, 670, "p, shift+p", 0]
  end
end

$game = Game.new

def tick args
  $game.args = args
  $game.tick
end

def set_angles x, y, z
  $game.state.angle_x = x
  $game.state.angle_y = y
  $game.state.angle_z = z
end

$gtk.reset

Ray Caster - main.rb link

# ./samples/99_genre_3d/04_ray_caster/app/main.rb
# https://github.com/BrennerLittle/DragonRubyRaycast
# https://github.com/3DSage/OpenGL-Raycaster_v1
# https://www.youtube.com/watch?v=gYRrGTC7GtA&ab_channel=3DSage

def tick args
  defaults args
  calc args
  render args
  args.outputs.sprites << { x: 0, y: 0, w: 1280 * 2.66, h: 720 * 2.25, path: :screen }
  args.outputs.labels  << { x: 30, y: 30.from_top, text: "FPS: #{args.gtk.current_framerate.to_sf}" }
end

def defaults args
  args.state.stage ||= {
    w: 8,
    h: 8,
    sz: 64,
    layout: [
      1, 1, 1, 1, 1, 1, 1, 1,
      1, 0, 1, 0, 0, 0, 0, 1,
      1, 0, 1, 0, 0, 1, 0, 1,
      1, 0, 1, 0, 0, 0, 0, 1,
      1, 0, 0, 0, 0, 0, 0, 1,
      1, 0, 0, 0, 0, 1, 0, 1,
      1, 0, 0, 0, 0, 0, 0, 1,
      1, 1, 1, 1, 1, 1, 1, 1,
    ]
  }

  args.state.player ||= {
    x: 250,
    y: 250,
    dx: 1,
    dy: 0,
    angle: 0
  }
end

def calc args
  xo = 0

  if args.state.player.dx < 0
    xo = -20
  else
    xo = 20
  end

  yo = 0

  if args.state.player.dy < 0
    yo = -20
  else
    yo = 20
  end

  ipx = args.state.player.x.idiv 64.0
  ipx_add_xo = (args.state.player.x + xo).idiv 64.0
  ipx_sub_xo = (args.state.player.x - xo).idiv 64.0

  ipy = args.state.player.y.idiv 64.0
  ipy_add_yo = (args.state.player.y + yo).idiv 64.0
  ipy_sub_yo = (args.state.player.y - yo).idiv 64.0

  if args.inputs.keyboard.right
    args.state.player.angle -= 5
    args.state.player.angle = args.state.player.angle % 360
    args.state.player.dx = args.state.player.angle.cos_d
    args.state.player.dy = -args.state.player.angle.sin_d
  end

  if args.inputs.keyboard.left
    args.state.player.angle += 5
    args.state.player.angle = args.state.player.angle % 360
    args.state.player.dx = args.state.player.angle.cos_d
    args.state.player.dy = -args.state.player.angle.sin_d
  end

  if args.inputs.keyboard.up
    if args.state.stage.layout[ipy * args.state.stage.w + ipx_add_xo] == 0
      args.state.player.x += args.state.player.dx * 5
    end

    if args.state.stage.layout[ipy_add_yo * args.state.stage.w + ipx] == 0
      args.state.player.y += args.state.player.dy * 5
    end
  end

  if args.inputs.keyboard.down
    if args.state.stage.layout[ipy * args.state.stage.w + ipx_sub_xo] == 0
      args.state.player.x -= args.state.player.dx * 5
    end

    if args.state.stage.layout[ipy_sub_yo * args.state.stage.w + ipx] == 0
      args.state.player.y -= args.state.player.dy * 5
    end
  end
end

def render args
  args.outputs[:screen].sprites << { x: 0,
                                     y: 160,
                                     w: 750,
                                     h: 160,
                                     path: :pixel,
                                     r: 89,
                                     g: 125,
                                     b: 206 }

  args.outputs[:screen].sprites << { x: 0,
                                     y: 0,
                                     w: 750,
                                     h: 160,
                                     path: :pixel,
                                     r: 117,
                                     g: 113,
                                     b: 97 }


  ra = (args.state.player.angle + 30) % 360

  60.times do |r|
    dof = 0
    side = 0
    dis_v = 100000
    ra_tan = ra.tan_d

    if ra.cos_d > 0.001
      rx = ((args.state.player.x >> 6) << 6) + 64
      ry = (args.state.player.x - rx) * ra_tan + args.state.player.y;
      xo = 64
      yo = -xo * ra_tan
    elsif ra.cos_d < -0.001
      rx = ((args.state.player.x >> 6) << 6) - 0.0001
      ry = (args.state.player.x - rx) * ra_tan + args.state.player.y
      xo = -64
      yo = -xo * ra_tan
    else
      rx = args.state.player.x
      ry = args.state.player.y
      dof = 8
    end

    while dof < 8
      mx = rx >> 6
      mx = mx.to_i
      my = ry >> 6
      my = my.to_i
      mp = my * args.state.stage.w + mx
      if mp > 0 && mp < args.state.stage.w * args.state.stage.h && args.state.stage.layout[mp] == 1
        dof = 8
        dis_v = ra.cos_d * (rx - args.state.player.x) - ra.sin_d * (ry - args.state.player.y)
      else
        rx += xo
        ry += yo
        dof += 1
      end
    end

    vx = rx
    vy = ry

    dof = 0
    dis_h = 100000
    ra_tan = 1.0 / ra_tan

    if ra.sin_d > 0.001
      ry = ((args.state.player.y >> 6) << 6) - 0.0001;
      rx = (args.state.player.y - ry) * ra_tan + args.state.player.x;
      yo = -64;
      xo = -yo * ra_tan;
    elsif ra.sin_d < -0.001
      ry = ((args.state.player.y >> 6) << 6) + 64;
      rx = (args.state.player.y - ry) * ra_tan + args.state.player.x;
      yo = 64;
      xo = -yo * ra_tan;
    else
      rx = args.state.player.x
      ry = args.state.player.y
      dof = 8
    end

    while dof < 8
      mx = (rx) >> 6
      my = (ry) >> 6
      mp = my * args.state.stage.w + mx
      if mp > 0 && mp < args.state.stage.w * args.state.stage.h && args.state.stage.layout[mp] == 1
        dof = 8
        dis_h = ra.cos_d * (rx - args.state.player.x) - ra.sin_d * (ry - args.state.player.y)
      else
        rx += xo
        ry += yo
        dof += 1
      end
    end

    color = { r: 52, g: 101, b: 36 }

    if dis_v < dis_h
      rx = vx
      ry = vy
      dis_h = dis_v
      color = { r: 109, g: 170, b: 44 }
    end

    ca = (args.state.player.angle - ra) % 360
    dis_h = dis_h * ca.cos_d
    line_h = (args.state.stage.sz * 320) / (dis_h)
    line_h = 320 if line_h > 320

    line_off = 160 - (line_h >> 1)

    args.outputs[:screen].sprites << {
      x: r * 8,
      y: line_off,
      w: 8,
      h: line_h,
      path: :pixel,
      **color
    }

    ra = (ra - 1) % 360
  end
end

Ray Caster Advanced - main.rb link

# ./samples/99_genre_3d/04_ray_caster_advanced/app/main.rb
=begin

This sample is a more advanced example of raycasting that extends the previous 04_ray_caster sample.
Refer to the prior sample to to understand the fundamental raycasting algorithm.
This sample adds:
 * higher resolution of raycasting
 * Wall textures
 * Simple "drop off" lighting
 * Weapon firing
 * Drawing of sprites within the level.

# Contributors outside of DragonRuby who also hold Copyright:
# - James Stocks: https://github.com/james-stocks

=end

# https://github.com/BrennerLittle/DragonRubyRaycast
# https://github.com/3DSage/OpenGL-Raycaster_v1
# https://www.youtube.com/watch?v=gYRrGTC7GtA&ab_channel=3DSage

def tick args
  defaults args
  update_player args
  update_missiles args
  update_enemies args
  render args
  args.outputs.sprites << { x: 0, y: 0, w: 1280 * 1.5, h: 720 * 1.2, path: :screen }
  args.outputs.labels  << { x: 30, y: 30.from_top, text: "FPS: #{args.gtk.current_framerate.to_sf} X: #{args.state.player.x} Y: #{args.state.player.y}" }
end

def defaults args
  args.state.stage ||= {
    w: 8,       # Width of the tile map
    h: 8,       # Height of the tile map
    sz: 64,     # To define a 3D space, define a size (in arbitrary units) we consider one map tile to be.
    layout: [
      1, 1, 1, 1, 2, 1, 1, 1,
      1, 0, 1, 0, 0, 0, 0, 1,
      1, 0, 1, 0, 0, 3, 0, 1,
      1, 0, 1, 0, 0, 0, 0, 2,
      1, 0, 0, 0, 0, 0, 0, 1,
      1, 0, 0, 0, 0, 3, 0, 1,
      1, 0, 0, 0, 0, 0, 0, 1,
      1, 1, 1, 2, 1, 1, 1, 1,
    ]
  }

  args.state.player ||= {
    x: 250,
    y: 250,
    dx: 1,
    dy: 0,
    angle: 0,
    fire_cooldown_wait: 0,
    fire_cooldown_duration: 15
  }

  # Add an initial alien enemy.
  # The :bright property indicates that this entity doesn't produce light and should appear dimmer over distance.
  args.state.enemies ||= [{ x: 280, y: 280, type: :alien, bright: false, expired: false }]
  args.state.missiles ||= []
  args.state.splashes ||= []
end

# Update the player's input and movement
def update_player args

  player = args.state.player
  player.fire_cooldown_wait -= 1 if player.fire_cooldown_wait > 0

  xo = 0

  if player.dx < 0
    xo = -20
  else
    xo = 20
  end

  yo = 0

  if player.dy < 0
    yo = -20
  else
    yo = 20
  end

  ipx = player.x.idiv 64.0
  ipx_add_xo = (player.x + xo).idiv 64.0
  ipx_sub_xo = (player.x - xo).idiv 64.0

  ipy = player.y.idiv 64.0
  ipy_add_yo = (player.y + yo).idiv 64.0
  ipy_sub_yo = (player.y - yo).idiv 64.0

  if args.inputs.keyboard.right
    player.angle -= 5
    player.angle = player.angle % 360
    player.dx = player.angle.cos_d
    player.dy = -player.angle.sin_d
  end

  if args.inputs.keyboard.left
    player.angle += 5
    player.angle = player.angle % 360
    player.dx = player.angle.cos_d
    player.dy = -player.angle.sin_d
  end

  if args.inputs.keyboard.up
    if args.state.stage.layout[ipy * args.state.stage.w + ipx_add_xo] == 0
      player.x += player.dx * 5
    end

    if args.state.stage.layout[ipy_add_yo * args.state.stage.w + ipx] == 0
      player.y += player.dy * 5
    end
  end

  if args.inputs.keyboard.down
    if args.state.stage.layout[ipy * args.state.stage.w + ipx_sub_xo] == 0
      player.x -= player.dx * 5
    end

    if args.state.stage.layout[ipy_sub_yo * args.state.stage.w + ipx] == 0
      player.y -= player.dy * 5
    end
  end

  if args.inputs.keyboard.key_down.space && player.fire_cooldown_wait == 0
    m = { x: player.x, y: player.y, angle: player.angle, speed: 6, type: :missile, bright: true, expired: false }
    # Immediately move the missile forward a frame so it spawns ahead of the player
    m.x += m.angle.cos_d * m.speed
    m.y -= m.angle.sin_d * m.speed
    args.state.missiles << m
    player.fire_cooldown_wait = player.fire_cooldown_duration
  end
end

def update_missiles args
  # Remove expired missiles by mapping expired missiles to `nil` and then calling `compact!` to
  # remove nil entries.
  args.state.missiles.map! { |m| m.expired ? nil : m }
  args.state.missiles.compact!

  args.state.missiles.each do |m|
    new_x = m.x + m.angle.cos_d * m.speed
    new_y = m.y - m.angle.sin_d * m.speed
    # Hit enemies
    args.state.enemies.each do |e|
        if (new_x - e.x).abs < 16 && (new_y - e.y).abs < 16
            e.expired = true
            m.expired = true
            args.state.splashes << { x: m.x, y: m.y, ttl: 5, type: :splash, bright: true }
            next
        end
    end
    # Hit walls
    if(args.state.stage.layout[(new_y / 64).to_i * args.state.stage.w + (new_x / 64).to_i] != 0)
      m.expired = true
      args.state.splashes << { x: m.x, y: m.y, ttl: 5, type: :splash, bright: true }
    else
      m.x = new_x
      m.y = new_y
    end
  end
  args.state.splashes.map! { |s| s.ttl <= 0 ? nil : s }
  args.state.splashes.compact!
  args.state.splashes.each do |s|
    s.ttl -= 1
  end
end

def update_enemies args
    args.state.enemies.map! { |e| e.expired ?  nil : e }
    args.state.enemies.compact!
end

def render args
  # Render the sky
  args.outputs[:screen].sprites << { x: 0,
                                     y: 320,
                                     w: 960,
                                     h: 320,
                                     path: :pixel,
                                     r: 89,
                                     g: 125,
                                     b: 206 }

  # Render the floor
  args.outputs[:screen].sprites << { x: 0,
                                     y: 0,
                                     w: 960,
                                     h: 320,
                                     path: :pixel,
                                     r: 117,
                                     g: 113,
                                     b: 97 }

  ra = (args.state.player.angle + 30) % 360

  # Collect sprites for the raycast view into an array - these will all be rendered with a single draw call.
  # This gives a substantial performance improvement over the previous sample where there was one draw call
  # per sprite.
  sprites_to_draw = []

  # Save distances of each wall hit. This is used subsequently when drawing sprites.
  depths = []

  # Cast 120 rays across 60 degress - we'll consider the next 0.5 degrees each ray
  120.times do |r|

    # The next ~120 lines are largely the same as the previous sample. The changes are:
    # - Increment by 0.5 degrees instead of 1 degree for the next ray.
    # - When a wall hit is found, the distance is stored in the `depths` array.
    #   - `depths` is used later when rendering enemies and bullet.
    # - We draw a slice of a wall texture instead of a solid color.
    # - The wall strip for the array hit is appended to `sprites_to_draw` instead of being drawn immediately.
    dof = 0
    max_dof = 8
    dis_v = 100000

    ra_tan = Math.tan(ra * Math::PI / 180)

    if ra.cos_d > 0.001
      rx = ((args.state.player.x >> 6) << 6) + 64

      ry = (args.state.player.x - rx) * ra_tan + args.state.player.y;
      xo = 64
      yo = -xo * ra_tan
    elsif ra.cos_d < -0.001
      rx = ((args.state.player.x >> 6) << 6) - 0.0001
      ry = (args.state.player.x - rx) * ra_tan + args.state.player.y
      xo = -64
      yo = -xo * ra_tan
    else
      rx = args.state.player.x
      ry = args.state.player.y
      dof = max_dof
    end

    while dof < max_dof
      mx = rx >> 6
      mx = mx.to_i
      my = ry >> 6
      my = my.to_i
      mp = my * args.state.stage.w + mx
      if mp > 0 && mp < args.state.stage.w * args.state.stage.h && args.state.stage.layout[mp] > 0
        dof = max_dof
        dis_v = ra.cos_d * (rx - args.state.player.x) - ra.sin_d * (ry - args.state.player.y)
        wall_texture_v = args.state.stage.layout[mp]
      else
        rx += xo
        ry += yo
        dof += 1
      end
    end

    vx = rx
    vy = ry

    dof = 0
    dis_h = 100000
    ra_tan = 1.0 / ra_tan

    if ra.sin_d > 0.001
      ry = ((args.state.player.y >> 6) << 6) - 0.0001;
      rx = (args.state.player.y - ry) * ra_tan + args.state.player.x;
      yo = -64;
      xo = -yo * ra_tan;
    elsif ra.sin_d < -0.001
      ry = ((args.state.player.y >> 6) << 6) + 64;
      rx = (args.state.player.y - ry) * ra_tan + args.state.player.x;
      yo = 64;
      xo = -yo * ra_tan;
    else
      rx = args.state.player.x
      ry = args.state.player.y
      dof = 8
    end

    while dof < 8
      mx = (rx) >> 6
      my = (ry) >> 6
      mp = my * args.state.stage.w + mx
      if mp > 0 && mp < args.state.stage.w * args.state.stage.h && args.state.stage.layout[mp] > 0
        dof = 8
        dis_h = ra.cos_d * (rx - args.state.player.x) - ra.sin_d * (ry - args.state.player.y)
        wall_texture = args.state.stage.layout[mp]
      else
        rx += xo
        ry += yo
        dof += 1
      end
    end

    dist = dis_h
    if dis_v < dis_h
      rx = vx
      ry = vy
      dist = dis_v
      wall_texture = wall_texture_v
    end
    # Store the distance for a wall hit at this angle
    depths << dist

    # Adjust for fish-eye across FOV
    ca = (args.state.player.angle - ra) % 360
    dist = dist * ca.cos_d
    # Determine the render height for the strip proportional to the display height
    line_h = (args.state.stage.sz * 640) / (dist)

    line_off = 320 - (line_h >> 1)

    # Tint the wall strip - the further away it is, the darker.
    tint = 1.0 - (dist / 500)

    # Wall texturing - Determine the section of source texture to use
    tx = dis_v > dis_h ? (rx.to_i % 64).to_i : (ry.to_i % 64).to_i
    # If player is looking backwards towards a tile then flip the side of the texture to sample.
    # The sample wall textures have a diagonal stripe pattern - if you comment out these 2 lines,
    # you will see what goes wrong with texturing.
    tx = 63 - tx if (ra > 180 && dis_v > dis_h)
    tx = 63 - tx if (ra > 90 && ra < 270 && dis_v < dis_h)

    sprites_to_draw << {
      x: r * 8,
      y: line_off,
      w: 8,
      h: line_h,
      path: "sprites/wall_#{wall_texture}.png",
      source_x: tx,
      source_w: 1,
      r: 255 * tint,
      g: 255 * tint,
      b: 255 * tint
    }

    # Increment the raycast angle for the next iteration of this loop
    ra = (ra - 0.5) % 360
  end

  # Render sprites
  # Use common render code for enemies, missiles and explosion splashes.
  # This works because they are all hashes with :x, :y, and :type fields.
  things_to_draw = []
  things_to_draw.push(*args.state.enemies)
  things_to_draw.push(*args.state.missiles)
  things_to_draw.push(*args.state.splashes)

  # Do a first-pass on the things to draw, calculate distance from player and then
  # sort so more-distant things are drawn first.
  things_to_draw.each do |t|
    t[:dist] = args.geometry.distance([args.state.player[:x],args.state.player[:y]],[t[:x],t[:y]]).abs
  end
  things_to_draw = things_to_draw.sort_by { |t| t[:dist] }.reverse

  # Now draw everything, most distant entities first.
  things_to_draw.each do |t|
      distance_to_thing = t[:dist]
      # The crux of drawing a sprite in a raycast view is to:
      #   1. rotate the enemy around the player's position and viewing angle to get a position relative to the view.
      #   2. Translate that position from "3D space" to screen pixels.
      # The next 6 lines get the entitiy's position relative to the player position and angle:
      tx = t[:x] - args.state.player.x
      ty = t[:y] - args.state.player.y
      cs = Math.cos(args.state.player.angle * Math::PI / 180)
      sn = Math.sin(args.state.player.angle * Math::PI / 180)
      dx = ty * cs + tx * sn
      dy = tx * cs - ty * sn

      # The next 5 lines determine the screen x and y of (the center of) the entity, and a scale
      next if dy == 0 # Avoid invalid Infinity/NaN calculations if the projected Y is 0
      ody = dy
      dx = dx*640/(dy) + 480
      dy = 32/dy + 192
      scale = 64*360/(ody / 2)

      tint = t[:bright] ? 1.0 : 1.0 - (distance_to_thing / 500)

      # Now we know the x and y on-screen for the entity, and its scale, we can draw it.
      # Simply drawing the sprite on the screen doesn't work in a raycast view because the entity might be partly obscured by a wall.
      # Instead we draw the entity in vertical strips, skipping strips if a wall is closer to the player on that strip of the screen.

      # Since dx stores the center x of the enemy on-screen, we start half the scale of the enemy to the left of dx
      x = dx - scale/2
      next if (x > 960 or (dx + scale/2 <= 0)) # Skip rendering if the X position is entirely off-screen
      strip = 0                    # Keep track of the number of strips we've drawn
      strip_width = scale / 64     # Draw the sprite in 64 strips
      sample_width = 1             # For each strip we will sample 1/64 of sprite image, here we assume 64x64 sprites

      until x >= dx + scale/2 do
          if x > 0 && x < 960
              # Here we get the distance to the wall for this strip on the screen
              wall_depth = depths[(x.to_i/8)]
              if ((distance_to_thing < wall_depth))
                  sprites_to_draw << {
                      x: x,
                      y: dy + 120 - scale * 0.6,
                      w: strip_width,
                      h: scale,
                      path: "sprites/#{t[:type]}.png",
                      source_x: strip * sample_width,
                      source_w: sample_width,
                      r: 255 * tint,
                      g: 255 * tint,
                      b: 255 * tint
                  }
              end
          end
          x += strip_width
          strip += 1
      end
  end

  # Draw all the sprites we collected in the array to the render target
  args.outputs[:screen].sprites << sprites_to_draw
end

Genre Arcade link

Bullet Heaven - main.rb link

# ./samples/99_genre_arcade/bullet_heaven/app/main.rb
class Game
  attr_gtk

  def initialize
    @level_scene = LevelScene.new
    @shop_scene = ShopScene.new
  end

  def tick
    defaults
    current_scene.args = args
    current_scene.tick
    if state.next_scene
      state.scene = state.next_scene
      state.scene_at = Kernel.tick_count
      state.next_scene = nil
    end
  end

  def current_scene
    if state.scene == :level
      @level_scene
    elsif state.scene == :shop
      @shop_scene
    end
  end

  def defaults
    state.shield ||= 10
    state.assembly_points ||= 4
    state.scene ||= :level
    state.bullets ||= []
    state.enemies ||= []
    state.bullet_speed ||= 5
    state.turret_position ||= { x: 640, y: 0 }
    state.blaster_spread ||= 1
    state.blaster_rate ||= 60
    state.level ||= 1
    state.bullet_damage ||= 1
    state.enemy_spawn_rate ||= 120
    state.enemy_min_health ||= 1
    state.enemy_health_range ||= 2
    state.enemies_to_spawn ||= 5
    state.enemies_spawned ||= 0
    state.enemy_dy ||= -0.2
  end
end

class ShopScene
  attr_gtk

  def activate
    state.module_selected = nil
    state.available_module_1 = :blaster_spread
    state.available_module_2 = :bullet_damage
    state.available_module_3 = if state.blaster_rate > 3
                                 :blaster_rate
                               else
                                 nil
                               end
  end

  def tick
    if state.scene_at == Kernel.tick_count - 1
      activate
    end

    state.next_wave_button ||= layout.rect(row: 0, col: 20, w: 4, h: 2)
    state.module_1_button  ||= layout.rect(row: 10, col: 0, w: 8, h: 2)
    state.module_2_button  ||= layout.rect(row: 10, col: 8, w: 8, h: 2)
    state.module_3_button  ||= layout.rect(row: 10, col: 16, w: 8, h: 2)

    calc
    render
  end

  def increase_difficulty_and_start_level
    state.next_scene = :level
    state.enemies_spawned = 0
    state.enemies = []
    state.level += 1
    state.enemy_spawn_rate = (state.enemy_spawn_rate * 0.95).to_i
    state.enemy_min_health = (state.enemy_min_health * 1.1).to_i + 1
    state.enemy_health_range = state.enemy_min_health * 2
    state.enemies_to_spawn = (state.enemies_to_spawn * 1.1).to_i + 2
    state.enemy_dy *= 1.05
  end

  def calc
    if state.module_selected
      if inputs.mouse.click && inputs.mouse.click.point.inside_rect?(state.next_wave_button)
        increase_difficulty_and_start_level
      end
    else
      if inputs.mouse.click && inputs.mouse.click.point.inside_rect?(state.module_1_button)
        perform_upgrade state.available_module_1
        state.available_module_1 = nil
        state.module_selected = true
      elsif inputs.mouse.click && inputs.mouse.click.point.inside_rect?(state.module_2_button)
        perform_upgrade state.available_module_2
        state.available_module_2 = nil
        state.module_selected = true
      elsif inputs.mouse.click && inputs.mouse.click.point.inside_rect?(state.module_3_button)
        perform_upgrade state.available_module_3
        state.available_module_3 = nil
        state.module_selected = true
      end
    end
  end

  def perform_upgrade module_name
    return if state.module_selected
    if module_name == :bullet_damage
      state.bullet_damage += 1
    elsif module_name == :blaster_rate
      state.blaster_rate = (state.blaster_rate * 0.85).to_i
      state.blaster_rate = 3 if state.blaster_rate < 3
    elsif module_name == :blaster_spread
      state.blaster_spread += 2
    else
      raise "perform_upgade: Unknown module: #{module_name}"
    end
  end

  def render
    outputs.background_color = [0, 0, 0]
    # outputs.primitives << layout.debug_primitives.map { |p| p.merge a: 80 }

    outputs.labels << layout.rect(row: 0, col: 11, w: 2, h: 1)
                            .center
                            .merge(text: "Select Upgrade", anchor_x: 0.5, anchor_y: 0.5, size_px: 50, r: 255, g: 255, b: 255)

    if state.module_selected
      outputs.primitives << button_prefab(state.next_wave_button, "Next Wave", a: 255)
    end

    a = if state.module_selected
          80
        else
          255
        end

    outputs.primitives << button_prefab(state.module_1_button, state.available_module_1, a: a)
    outputs.primitives << button_prefab(state.module_2_button, state.available_module_2, a: a)
    outputs.primitives << button_prefab(state.module_3_button, state.available_module_3, a: a)
  end

  def button_prefab rect, text, a: 255
    return nil if !text
    [
      rect.merge(path: :solid, r: 255, g: 255, b: 255, a: a),
      geometry.center(rect).merge(text: text.gsub("_", " "), anchor_x: 0.5, anchor_y: 0.5, r: 0, g: 0, b: 0, size_px: rect.h.idiv(4))
    ]
  end
end

class LevelScene
  attr_gtk

  def tick
    if inputs.keyboard.key_down.g
      state.enemies_spawned = state.enemies_to_spawn
      state.enemies = []
    elsif inputs.keyboard.key_down.forward_slash
      roll = rand
      if roll < 0.33
        state.bullet_damage += 1
        $gtk.notify_extended! message: "bullet damage increased: #{state.bullet_damage}", env: :prod
      elsif roll < 0.66
        if state.blaster_rate > 3
          state.blaster_rate = (state.blaster_rate * 0.85).to_i
          state.blaster_rate = 3 if state.blaster_rate < 3
          $gtk.notify_extended! message: "blaster rate upgraded: #{state.blaster_rate}", env: :prod
        else
          $gtk.notify_extended! message: "blaster rate already at fastest.", env: :prod
        end
      else
        state.blaster_spread += 2
        $gtk.notify_extended! message: "blaster spread increased: #{state.blaster_spread}", env: :prod
      end
    end

    calc
    render
  end

  def calc
    calc_bullets
    calc_enemies
    calc_bullet_hits
    calc_enemy_push_back
    calc_deaths
  end

  def calc_deaths
    state.enemies.reject! { |e| e.hp <= 0 }
    state.bullets.reject! { |b| b.dead_at }
  end

  def enemy_prefab enemy
    b = (enemy.hp / (state.enemy_min_health + state.enemy_health_range)) * 255
    [
      enemy.merge(path: :solid, r: 128, g: 0, b: b),
      geometry.center(enemy).merge(text: enemy.hp, anchor_x: 0.5, anchor_y: 0.5, r: 255, g: 255, b: 255, size_px: enemy.h * 0.5)
    ]
  end

  def render
    outputs.background_color = [0, 0, 0]
    level_completion_perc = (state.enemies_spawned - state.enemies.length).fdiv(state.enemies_to_spawn)
    outputs.primitives << { x: 30, y: 30.from_top, text: "Wave: #{state.level} (#{(level_completion_perc * 100).to_i}% complete)", r: 255, g: 255, b: 255 }
    outputs.primitives << { x: 30, y: 60.from_top, text: "Press G to skip to end of the current wave.", r: 255, g: 255, b: 255 }
    outputs.primitives << { x: 30, y: 90.from_top, text: "Press / to get a random upgrade immediately.", r: 255, g: 255, b: 255 }

    outputs.sprites << state.bullets.map do |b|
      b.merge w: 10, h: 10, path: :solid, r: 0, g: 255, b: 255
    end

    outputs.primitives << state.enemies.map { |e| enemy_prefab e }
  end

  def calc_bullets
    if Kernel.tick_count.zmod? state.blaster_rate
      bullet_count = state.blaster_spread
      min_degrees = state.blaster_spread.idiv(2) * -2
      bullet_count.times do |i|
        degree_offset = min_degrees + (i * 2)
        state.bullets << { x: 640,
                           y: 0,
                           dy: (attack_angle + degree_offset).vector_y * state.bullet_speed,
                           dx: (attack_angle + degree_offset).vector_x * state.bullet_speed }
      end
    end

    state.bullets.each do |b|
      b.x += b.dx
      b.y += b.dy
    end

    state.bullets.reject! { |b| b.y < 0 || b.y > 720 || b.x > 1280 || b.x < 0 }
  end

  def calc_enemies
    if Kernel.tick_count.zmod?(state.enemy_spawn_rate) && state.enemies_spawned < state.enemies_to_spawn
      state.enemies_spawned += 1
      x = rand(1280 - 96) + 48
      y = 720
      hp = state.enemy_min_health + rand(state.enemy_health_range)
      state.enemies << { x: x,
                         y: y,
                         w: 48,
                         h: 48,
                         push_back_x: 0,
                         push_back_y: 0,
                         spawn_at: Kernel.tick_count,
                         dy: state.enemy_dy,
                         start_hp: hp,
                         hp: hp }
    end

    state.enemies.each do |e|
      if e.y + e.h > 720
        e.y -= (((e.y + e.h) - 720) / e.h) * 10
      end

      e.y += e.dy

      if e.x < 0 && e.push_back_x < 0
        e.push_back_x = e.push_back_x.abs
      elsif (e.x + e.w) > 1280 && e.push_back_x > 0
        e.push_back_x = e.push_back_x.abs * -1
      end

      e.x += e.push_back_x
      e.y += e.push_back_y

      e.push_back_x *= 0.9
      e.push_back_y *= 0.9
    end

    state.enemies.reject! { |e| e.y < 0 }

    if state.enemies.empty? && state.enemies_spawned >= state.enemies_to_spawn
      state.next_scene = :shop
      state.bullets.clear
    end
  end

  def calc_bullet_hits
    state.bullets.each do |b|
      state.enemies.each do |e|
        if geometry.intersect_rect? b.merge(w: 4, h: 4, anchor_x: 0.5, anchor_x: 0.5), e
          e.hp -= state.bullet_damage
          push_back_angle = geometry.angle b, geometry.center(e)
          push_back_x = push_back_angle.vector_x * state.bullet_damage * 0.1
          push_back_y = push_back_angle.vector_y * state.bullet_damage * 0.1
          e.push_back_x += push_back_x
          e.push_back_y += push_back_y
          e.hit_at = Kernel.tick_count
          b.dead_at = Kernel.tick_count
        end
      end
    end
  end

  def calc_enemy_push_back
    state.enemies.sort_by { |e| -e.y }.each do |e|
      has_pushed_back = false
      other_enemies = geometry.find_all_intersect_rect e, state.enemies
      other_enemies.each do |e2|
        next if e == e2
        push_back_angle = geometry.angle geometry.center(e), geometry.center(e2)
        e2.push_back_x += (e.push_back_x).fdiv(other_enemies.length) * 0.7
        e2.push_back_y += (e.push_back_y).fdiv(other_enemies.length) * 0.7
        has_pushed_back = true
      end

      if has_pushed_back
        e.push_back_x *= 0.2
        e.push_back_y *= 0.2
      end
    end
  end

  def attack_angle
    geometry.angle state.turret_position, inputs.mouse
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

def reset
  $game = nil
end

$gtk.reset

Bullet Hell - main.rb link

# ./samples/99_genre_arcade/bullet_hell/app/main.rb
def tick args
  args.state.base_columns   ||= 10.map { |n| 50 * n + 1280 / 2 - 5 * 50 + 5 }
  args.state.base_rows      ||= 5.map { |n| 50 * n + 720 - 5 * 50 }
  args.state.offset_columns = 10.map { |n| (n - 4.5) * Math.sin(Kernel.tick_count.to_radians) * 12 }
  args.state.offset_rows    = 5.map { 0 }
  args.state.columns        = 10.map { |i| args.state.base_columns[i] + args.state.offset_columns[i] }
  args.state.rows           = 5.map { |i| args.state.base_rows[i] + args.state.offset_rows[i] }
  args.state.explosions     ||= []
  args.state.enemies        ||= []
  args.state.score          ||= 0
  args.state.wave           ||= 0
  if args.state.enemies.empty?
    args.state.wave      += 1
    args.state.wave_root = Math.sqrt(args.state.wave)
    args.state.enemies   = make_enemies
  end
  args.state.player         ||= {x: 620, y: 80, w: 40, h: 40, path: 'sprites/circle-gray.png', angle: 90, cooldown: 0, alive: true}
  args.state.enemy_bullets  ||= []
  args.state.player_bullets ||= []
  args.state.lives          ||= 3
  args.state.missed_shots   ||= 0
  args.state.fired_shots    ||= 0

  update_explosions args
  update_enemy_positions args

  if args.inputs.left && args.state.player[:x] > (300 + 5)
    args.state.player[:x] -= 5
  end
  if args.inputs.right && args.state.player[:x] < (1280 - args.state.player[:w] - 300 - 5)
    args.state.player[:x] += 5
  end

  args.state.enemy_bullets.each do |bullet|
    bullet[:x] += bullet[:dx]
    bullet[:y] += bullet[:dy]
  end
  args.state.player_bullets.each do |bullet|
    bullet[:x] += bullet[:dx]
    bullet[:y] += bullet[:dy]
  end

  args.state.enemy_bullets  = args.state.enemy_bullets.find_all { |bullet| bullet[:y].between?(-16, 736) }
  args.state.player_bullets = args.state.player_bullets.find_all do |bullet|
    if bullet[:y].between?(-16, 736)
      true
    else
      args.state.missed_shots += 1
      false
    end
  end

  args.state.enemies = args.state.enemies.reject do |enemy|
    if args.state.player[:alive] && 1500 > (args.state.player[:x] - enemy[:x]) ** 2 + (args.state.player[:y] - enemy[:y]) ** 2
      args.state.explosions << {x: enemy[:x] + 4, y: enemy[:y] + 4, w: 32, h: 32, path: 'sprites/explosion-0.png', age: 0}
      args.state.explosions << {x: args.state.player[:x] + 4, y: args.state.player[:y] + 4, w: 32, h: 32, path: 'sprites/explosion-0.png', age: 0}
      args.state.player[:alive] = false
      true
    else
      false
    end
  end
  args.state.enemy_bullets.each do |bullet|
    if args.state.player[:alive] && 400 > (args.state.player[:x] - bullet[:x] + 12) ** 2 + (args.state.player[:y] - bullet[:y] + 12) ** 2
      args.state.explosions << {x: args.state.player[:x] + 4, y: args.state.player[:y] + 4, w: 32, h: 32, path: 'sprites/explosion-0.png', age: 0}
      args.state.player[:alive] = false
      bullet[:despawn]          = true
    end
  end
  args.state.enemies = args.state.enemies.reject do |enemy|
    args.state.player_bullets.any? do |bullet|
      if 400 > (enemy[:x] - bullet[:x] + 12) ** 2 + (enemy[:y] - bullet[:y] + 12) ** 2
        args.state.explosions << {x: enemy[:x] + 4, y: enemy[:y] + 4, w: 32, h: 32, path: 'sprites/explosion-0.png', age: 0}
        bullet[:despawn] = true
        args.state.score += 1000 * args.state.wave
        true
      else
        false
      end
    end
  end

  args.state.player_bullets = args.state.player_bullets.reject { |bullet| bullet[:despawn] }
  args.state.enemy_bullets  = args.state.enemy_bullets.reject { |bullet| bullet[:despawn] }

  args.state.player[:cooldown] -= 1
  if args.inputs.keyboard.key_held.space && args.state.player[:cooldown] <= 0 && args.state.player[:alive]
    args.state.player_bullets << {x: args.state.player[:x] + 12, y: args.state.player[:y] + 28, w: 16, h: 16, path: 'sprites/star.png', dx: 0, dy: 8}.sprite
    args.state.fired_shots       += 1
    args.state.player[:cooldown] = 10 + 20 / args.state.wave
  end
  args.state.enemies.each do |enemy|
    if Math.rand < 0.0005 + 0.0005 * args.state.wave && args.state.player[:alive] && enemy[:move_state] == :normal
      args.state.enemy_bullets << {x: enemy[:x] + 12, y: enemy[:y] - 8, w: 16, h: 16, path: 'sprites/star.png', dx: 0, dy: -3 - args.state.wave_root}.sprite
    end
  end

  args.outputs.background_color = [0, 0, 0]
  args.outputs.primitives << args.state.enemies.map do |enemy|
    [enemy[:x], enemy[:y], 40, 40, enemy[:path], -90].sprite
  end
  args.outputs.primitives << args.state.player if args.state.player[:alive]
  args.outputs.primitives << args.state.explosions
  args.outputs.primitives << args.state.player_bullets
  args.outputs.primitives << args.state.enemy_bullets
  accuracy = args.state.fired_shots.zero? ? 1 : (args.state.fired_shots - args.state.missed_shots) / args.state.fired_shots
  args.outputs.primitives << [
    [0, 0, 300, 720, 96, 0, 0].solid,
    [1280 - 300, 0, 300, 720, 96, 0, 0].solid,
    [1280 - 290, 60, "Wave     #{args.state.wave}", 255, 255, 255].label,
    [1280 - 290, 40, "Accuracy #{(accuracy * 100).floor}%", 255, 255, 255].label,
    [1280 - 290, 20, "Score    #{(args.state.score * accuracy).floor}", 255, 255, 255].label,
  ]
  args.outputs.primitives << args.state.lives.map do |n|
    [1280 - 290 + 50 * n, 80, 40, 40, 'sprites/circle-gray.png', 90].sprite
  end
  #args.outputs.debug << args.gtk.framerate_diagnostics_primitives

  if (!args.state.player[:alive]) && args.state.enemy_bullets.empty? && args.state.explosions.empty? && args.state.enemies.all? { |enemy| enemy[:move_state] == :normal }
    args.state.player[:alive] = true
    args.state.player[:x]     = 624
    args.state.player[:y]     = 80
    args.state.lives          -= 1
    if args.state.lives == -1
      args.state.clear!
    end
  end
end

def make_enemies
  enemies = []
  enemies += 10.map { |n| {x: Math.rand * 1280 * 2 - 640, y: Math.rand * 720 * 2 + 720, row: 0, col: n, path: 'sprites/circle-orange.png', move_state: :retreat} }
  enemies += 10.map { |n| {x: Math.rand * 1280 * 2 - 640, y: Math.rand * 720 * 2 + 720, row: 1, col: n, path: 'sprites/circle-orange.png', move_state: :retreat} }
  enemies += 8.map { |n| {x: Math.rand * 1280 * 2 - 640, y: Math.rand * 720 * 2 + 720, row: 2, col: n + 1, path: 'sprites/circle-blue.png', move_state: :retreat} }
  enemies += 8.map { |n| {x: Math.rand * 1280 * 2 - 640, y: Math.rand * 720 * 2 + 720, row: 3, col: n + 1, path: 'sprites/circle-blue.png', move_state: :retreat} }
  enemies += 4.map { |n| {x: Math.rand * 1280 * 2 - 640, y: Math.rand * 720 * 2 + 720, row: 4, col: n + 3, path: 'sprites/circle-green.png', move_state: :retreat} }
  enemies
end

def update_explosions args
  args.state.explosions.each do |explosion|
    explosion[:age]  += 0.5
    explosion[:path] = "sprites/explosion-#{explosion[:age].floor}.png"
  end
  args.state.explosions = args.state.explosions.reject { |explosion| explosion[:age] >= 7 }
end

def update_enemy_positions args
  args.state.enemies.each do |enemy|
    if enemy[:move_state] == :normal
      enemy[:x]          = args.state.columns[enemy[:col]]
      enemy[:y]          = args.state.rows[enemy[:row]]
      enemy[:move_state] = :dive if Math.rand < 0.0002 + 0.00005 * args.state.wave && args.state.player[:alive]
    elsif enemy[:move_state] == :dive
      enemy[:target_x] ||= args.state.player[:x]
      enemy[:target_y] ||= args.state.player[:y]
      dx               = enemy[:target_x] - enemy[:x]
      dy               = enemy[:target_y] - enemy[:y]
      vel              = Math.sqrt(dx * dx + dy * dy)
      speed_limit      = 2 + args.state.wave_root
      if vel > speed_limit
        dx /= vel / speed_limit
        dy /= vel / speed_limit
      end
      if vel < 1 || !args.state.player[:alive]
        enemy[:move_state] = :retreat
      end
      enemy[:x] += dx
      enemy[:y] += dy
    elsif enemy[:move_state] == :retreat
      enemy[:target_x] = args.state.columns[enemy[:col]]
      enemy[:target_y] = args.state.rows[enemy[:row]]
      dx               = enemy[:target_x] - enemy[:x]
      dy               = enemy[:target_y] - enemy[:y]
      vel              = Math.sqrt(dx * dx + dy * dy)
      speed_limit      = 2 + args.state.wave_root
      if vel > speed_limit
        dx /= vel / speed_limit
        dy /= vel / speed_limit
      elsif vel < 1
        enemy[:move_state] = :normal
        enemy[:target_x]   = nil
        enemy[:target_y]   = nil
      end
      enemy[:x] += dx
      enemy[:y] += dy
    end
  end
end

Dueling Starships - main.rb link

# ./samples/99_genre_arcade/dueling_starships/app/main.rb
class DuelingSpaceships
  attr_gtk

  def tick
    defaults
    render
    calc
    input
  end

  def defaults
    outputs.background_color = [0, 0, 0]
    state.ship_blue       ||= new_blue_ship
    state.ship_red        ||= new_red_ship
    state.flames          ||= []
    state.bullets         ||= []
    state.ship_blue_score ||= 0
    state.ship_red_score  ||= 0
    state.stars           ||= 100.map do
      (rand + 2).yield_self do |size|
        { x: grid.w_half.randomize(:sign, :ratio),
          y: grid.h_half.randomize(:sign, :ratio),
          w: size,
          h: size,
          r: 128 + 128 * rand,
          g: 255,
          b: 255,
          path: :solid }
      end
    end
  end

  def new_ship x:, y:, angle:, path:, bullet_path:, color:;
    { x: x, y: y, w: 66, h: 66,
      dy: 0, dx: 0,
      anchor_x: 0.5, anchor_y: 0.5,
      damage: 0,
      dead: false,
      angle: angle,
      a: 255,
      path: path,
      bullet_sprite_path: bullet_path,
      color: color,
      created_at: Kernel.tick_count,
      last_bullet_at: 0,
      fire_rate: 10 }
  end

  def new_red_ship
    new_ship x: 400,
             y: 250.randomize(:sign, :ratio),
             angle: 180, path: 'sprites/ship_red.png',
             bullet_path: 'sprites/red_bullet.png',
             color: { r: 255, g: 90, b: 90 }
  end

  def new_blue_ship
    new_ship x: -400,
             y: 250.randomize(:sign, :ratio),
             angle: 0,
             path: 'sprites/ship_blue.png',
             bullet_path: 'sprites/blue_bullet.png',
             color: { r: 110, g: 140, b: 255 }
  end

  def render
    render_instructions
    render_score
    render_universe
    render_flames
    render_ships
    render_bullets
  end

  def render_ships
    outputs.primitives << ship_prefab(state.ship_blue)
    outputs.primitives << ship_prefab(state.ship_red)
  end

  def render_instructions
    return if state.ship_blue.dx  > 0  || state.ship_blue.dy > 0  ||
              state.ship_red.dx   > 0  || state.ship_red.dy  > 0  ||
              state.flames.length > 0

    outputs.labels << { x: grid.left.shift_right(30),
                        y: grid.bottom.shift_up(30),
                        text: "Two gamepads needed to play. R1 to accelerate. Left and right on D-PAD to turn ship. Hold A to shoot. Press B to drop mines.",
                        r: 255, g: 255, b: 255 }
  end

  def calc
    calc_flames
    calc_ships
    calc_bullets
    calc_winner
  end

  def input
    input_accelerate
    input_turn
    input_bullets_and_mines
  end

  def render_score
    outputs.labels << { x: grid.left.shift_right(80),
                        y: grid.top.shift_down(40),
                        text: state.ship_blue_score,
                        size_enum: 30,
                        alignment_enum: 1, **state.ship_blue.color }

    outputs.labels << { x: grid.right.shift_left(80),
                        y: grid.top.shift_down(40),
                        text: state.ship_red_score,
                        size_enum: 30,
                        alignment_enum: 1, **state.ship_red.color }
  end

  def render_universe
    args.outputs.background_color = [0, 0, 0]
    outputs.sprites << state.stars
  end

  def apply_round_finished_alpha entity
    return entity unless state.round_finished_at
    entity.merge(a: (entity.a || 0) * state.round_finished_at.ease(2.seconds, :flip))
  end

  def ship_prefab ship
    [
      apply_round_finished_alpha(**ship,
                                 a: ship.dead ? 0 : 255 * ship.created_at.ease(2.seconds)),

      apply_round_finished_alpha(x: ship.x,
                                 y: ship.y + 100,
                                 text: "." * (5 - ship.damage.clamp(0, 5)),
                                 size_enum: 20,
                                 alignment_enum: 1,
                                 **ship.color)
    ]
  end

  def render_flames
    outputs.sprites << state.flames.map do |flame|
      apply_round_finished_alpha(flame.merge(a: 255 * flame.created_at.ease(flame.lifetime, :flip)))
    end
  end

  def render_bullets
    outputs.sprites << state.bullets.map do |b|
      apply_round_finished_alpha(b.merge(a: 255 * b.owner.created_at.ease(2.seconds)))
    end
  end

  def wrap_location! location
    location.merge! x: location.x.clamp_wrap(grid.left, grid.right),
                    y: location.y.clamp_wrap(grid.bottom, grid.top)
  end

  def calc_flames
    state.flames =
      state.flames
           .reject { |p| p.created_at.elapsed_time > p.lifetime }
           .map do |p|
             p.speed *= 0.9
             p.y += p.angle.vector_y(p.speed)
             p.x += p.angle.vector_x(p.speed)
             wrap_location! p
           end
  end

  def all_ships
    [state.ship_blue, state.ship_red]
  end

  def alive_ships
    all_ships.reject { |s| s.dead }
  end

  def calc_bullet bullet
    bullet.y += bullet.angle.vector_y(bullet.speed)
    bullet.x += bullet.angle.vector_x(bullet.speed)
    wrap_location! bullet
    explode_bullet! bullet, particle_count: 5 if bullet.created_at.elapsed_time > bullet.lifetime
    return if bullet.exploded
    return if state.round_finished
    alive_ships.each do |s|
      if s != bullet.owner && s.intersect_rect?(bullet)
        explode_bullet! bullet, particle_count: 10
        s.damage += 1
      end
    end
  end

  def calc_bullets
    state.bullets.each    { |b| calc_bullet b }
    state.bullets.reject! { |b| b.exploded }
  end

  def new_flame x:, y:, angle:, a:, lifetime:, speed:;
    { angle: angle,
      speed: speed,
      lifetime: lifetime,
      path: 'sprites/flame.png',
      x: x,
      y: y,
      w: 6,
      h: 6,
      anchor_x: 0.5,
      anchor_y: 0.5,
      created_at: Kernel.tick_count,
      a: a }
  end

  def create_explosion! source:, particle_count:, max_speed:, lifetime:;
    state.flames.concat(particle_count.map do
                          new_flame x: source.x,
                                    y: source.y,
                                    speed: max_speed * rand,
                                    angle: 360 * rand,
                                    lifetime: lifetime,
                                    a: source.a
                        end)
  end

  def explode_bullet! bullet, particle_count: 5
    bullet.exploded = true
    create_explosion! source: bullet,
                      particle_count: particle_count,
                      max_speed: 5,
                      lifetime: 10
  end

  def calc_ship ship
    ship.x += ship.dx
    ship.y += ship.dy
    wrap_location! ship
  end

  def calc_ships
    all_ships.each { |s| calc_ship s }
    return if all_ships.any? { |s| s.dead }
    return if state.round_finished
    return unless state.ship_blue.intersect_rect?(state.ship_red)
    state.ship_blue.damage = 5
    state.ship_red.damage  = 5
  end

  def create_thruster_flames! ship
    state.flames << new_flame(x: ship.x - ship.angle.vector_x(40) + 5.randomize(:sign, :ratio),
                              y: ship.y - ship.angle.vector_y(40) + 5.randomize(:sign, :ratio),
                              angle: ship.angle + 180 + 60.randomize(:sign, :ratio),
                              speed: 5.randomize(:ratio),
                              a: 255 * ship.created_at.elapsed_time.ease(2.seconds),
                              lifetime: 30)
  end

  def input_accelerate_ship should_move_ship, ship
    return if ship.dead

    should_move_ship &&= (ship.dx + ship.dy).abs < 5

    if should_move_ship
      create_thruster_flames! ship
      ship.dx += ship.angle.vector_x 0.050
      ship.dy += ship.angle.vector_y 0.050
    else
      ship.dx *= 0.99
      ship.dy *= 0.99
    end
  end

  def input_accelerate
    input_accelerate_ship inputs.controller_one.key_held.r1 || inputs.keyboard.up, state.ship_blue
    input_accelerate_ship inputs.controller_two.key_held.r1, state.ship_red
  end

  def input_turn_ship direction, ship
    ship.angle -= 3 * direction
  end

  def input_turn
    input_turn_ship inputs.controller_one.left_right + inputs.keyboard.left_right, state.ship_blue
    input_turn_ship inputs.controller_two.left_right, state.ship_red
  end

  def new_bullet x:, y:, ship:, angle:, speed:, lifetime:;
    { owner: ship,
      angle: angle,
      speed: speed,
      lifetime: lifetime,
      created_at: Kernel.tick_count,
      path: ship.bullet_sprite_path,
      anchor_x: 0.5,
      anchor_y: 0.5,
      w: 10,
      h: 10,
      x: x,
      y: y }
  end

  def input_bullet create_bullet, ship
    return unless create_bullet
    return if ship.dead
    return if ship.last_bullet_at.elapsed_time < ship.fire_rate

    ship.last_bullet_at = Kernel.tick_count

    state.bullets << new_bullet(x: ship.x + ship.angle.vector_x * 32,
                                y: ship.y + ship.angle.vector_y * 32,
                                ship: ship,
                                angle: ship.angle,
                                speed: 5 + ship.dx * ship.angle.vector_x + ship.dy * ship.angle.vector_y,
                                lifetime: 120)
  end

  def input_mine create_mine, ship
    return unless create_mine
    return if ship.dead

    state.bullets << new_bullet(x: ship.x + ship.angle.vector_x * -50,
                                y: ship.y + ship.angle.vector_y * -50,
                                ship: ship,
                                angle: 360.randomize(:sign, :ratio),
                                speed: 0.02,
                                lifetime: 600)
  end

  def input_bullets_and_mines
    return if state.bullets.length > 100

    input_bullet(inputs.controller_one.key_held.a || inputs.keyboard.key_held.space,
                 state.ship_blue)

    input_mine(inputs.controller_one.key_down.b || inputs.keyboard.key_down.down,
               state.ship_blue)

    input_bullet(inputs.controller_two.key_held.a, state.ship_red)

    input_mine(inputs.controller_two.key_down.b, state.ship_red)
  end

  def calc_kill_ships
    alive_ships.find_all { |s| s.damage >= 5 }
               .each do |s|
                 s.dead = true
                 create_explosion! source: s,
                                   particle_count: 20,
                                   max_speed: 20,
                                   lifetime: 30
               end
  end

  def calc_score
    return if state.round_finished
    return if alive_ships.length > 1

    if alive_ships.first == state.ship_red
      state.ship_red_score += 1
    elsif alive_ships.first == state.ship_blue
      state.ship_blue_score += 1
    end

    state.round_finished = true
  end

  def calc_reset_ships
    return unless state.round_finished
    state.round_finished_at ||= Kernel.tick_count
    return if state.round_finished_at.elapsed_time <= 2.seconds
    start_new_round!
  end

  def start_new_round!
    state.ship_blue = new_blue_ship
    state.ship_red  = new_red_ship
    state.round_finished = false
    state.round_finished_at = nil
    state.flames.clear
    state.bullets.clear
  end

  def calc_winner
    calc_kill_ships
    calc_score
    calc_reset_ships
  end
end

$dueling_spaceship = DuelingSpaceships.new

def tick args
  args.grid.origin_center!
  $dueling_spaceship.args = args
  $dueling_spaceship.tick
end

arcade/flappy dragon/credits.txt link

# ./samples/99_genre_arcade/flappy_dragon/CREDITS.txt
code: Amir Rajan, https://twitter.com/amirrajan
graphics and audio: Nick Culbertson, https://twitter.com/MobyPixel

arcade/flappy dragon/main.rb link

# ./samples/99_genre_arcade/flappy_dragon/app/main.rb
class FlappyDragon
  attr_accessor :grid, :inputs, :state, :outputs

  def tick
    defaults
    render
    calc
    process_inputs
  end

  def defaults
    state.flap_power              = 11
    state.gravity                 = 0.9
    state.ceiling                 = 600
    state.ceiling_flap_power      = 6
    state.wall_countdown_length   = 100
    state.wall_gap_size           = 100
    state.wall_countdown        ||= 0
    state.hi_score              ||= 0
    state.score                 ||= 0
    state.walls                 ||= []
    state.x                     ||= 50
    state.y                     ||= 500
    state.dy                    ||= 0
    state.scene                 ||= :menu
    state.scene_at              ||= 0
    state.difficulty            ||= :normal
    state.new_difficulty        ||= :normal
    state.countdown             ||= 4.seconds
    state.flash_at              ||= 0
  end

  def render
    outputs.sounds << "sounds/flappy-song.ogg" if Kernel.tick_count == 1
    render_score
    render_menu
    render_game
  end

  def render_score
    outputs.primitives << { x: 10, y: 710, text: "HI SCORE: #{state.hi_score}", **large_white_typeset }
    outputs.primitives << { x: 10, y: 680, text: "SCORE: #{state.score}", **large_white_typeset }
    outputs.primitives << { x: 10, y: 650, text: "DIFFICULTY: #{state.difficulty.upcase}", **large_white_typeset }
  end

  def render_menu
    return unless state.scene == :menu
    render_overlay

    outputs.labels << { x: 640, y: 700, text: "Flappy Dragon", size_enum: 50, alignment_enum: 1, **white }
    outputs.labels << { x: 640, y: 500, text: "Instructions: Press Spacebar to flap. Don't die.", size_enum: 4, alignment_enum: 1, **white }
    outputs.labels << { x: 430, y: 430, text: "[Tab]    Change difficulty", size_enum: 4, alignment_enum: 0, **white }
    outputs.labels << { x: 430, y: 400, text: "[Enter]  Start at New Difficulty ", size_enum: 4, alignment_enum: 0, **white }
    outputs.labels << { x: 430, y: 370, text: "[Escape] Cancel/Resume ", size_enum: 4, alignment_enum: 0, **white }
    outputs.labels << { x: 640, y: 300, text: "(mouse, touch, and game controllers work, too!) ", size_enum: 4, alignment_enum: 1, **white }
    outputs.labels << { x: 640, y: 200, text: "Difficulty: #{state.new_difficulty.capitalize}", size_enum: 4, alignment_enum: 1, **white }

    outputs.labels << { x: 10, y: 100, text: "Code:   @amirrajan",     **white }
    outputs.labels << { x: 10, y:  80, text: "Art:    @mobypixel",     **white }
    outputs.labels << { x: 10, y:  60, text: "Music:  @mobypixel",     **white }
    outputs.labels << { x: 10, y:  40, text: "Engine: DragonRuby GTK", **white }
  end

  def render_overlay
    overlay_rect = grid.rect.scale_rect(1.1, 0, 0)
    outputs.primitives << { x: overlay_rect.x,
                            y: overlay_rect.y,
                            w: overlay_rect.w,
                            h: overlay_rect.h,
                            r: 0, g: 0, b: 0, a: 230 }.solid!
  end

  def render_game
    render_game_over
    render_background
    render_walls
    render_dragon
    render_flash
  end

  def render_game_over
    return unless state.scene == :game
    outputs.labels << { x: 638, y: 358, text: score_text,     size_enum: 20, alignment_enum: 1 }
    outputs.labels << { x: 635, y: 360, text: score_text,     size_enum: 20, alignment_enum: 1, r: 255, g: 255, b: 255 }
    outputs.labels << { x: 638, y: 428, text: countdown_text, size_enum: 20, alignment_enum: 1 }
    outputs.labels << { x: 635, y: 430, text: countdown_text, size_enum: 20, alignment_enum: 1, r: 255, g: 255, b: 255 }
  end

  def render_background
    outputs.sprites << { x: 0, y: 0, w: 1280, h: 720, path: 'sprites/background.png' }

    scroll_point_at   = Kernel.tick_count
    scroll_point_at   = state.scene_at if state.scene == :menu
    scroll_point_at   = state.death_at if state.countdown > 0
    scroll_point_at ||= 0

    outputs.sprites << scrolling_background(scroll_point_at, 'sprites/parallax_back.png',   0.25)
    outputs.sprites << scrolling_background(scroll_point_at, 'sprites/parallax_middle.png', 0.50)
    outputs.sprites << scrolling_background(scroll_point_at, 'sprites/parallax_front.png',  1.00, -80)
  end

  def scrolling_background at, path, rate, y = 0
    [
      { x:    0 - at.*(rate) % 1440, y: y, w: 1440, h: 720, path: path },
      { x: 1440 - at.*(rate) % 1440, y: y, w: 1440, h: 720, path: path }
    ]
  end

  def render_walls
    state.walls.each do |w|
      w.sprites = [
        { x: w.x, y: w.bottom_height - 720, w: 100, h: 720, path: 'sprites/wall.png',       angle: 180 },
        { x: w.x, y: w.top_y,               w: 100, h: 720, path: 'sprites/wallbottom.png', angle: 0 }
      ]
    end
    outputs.sprites << state.walls.map(&:sprites)
  end

  def render_dragon
    state.show_death = true if state.countdown == 3.seconds

    if state.show_death == false || !state.death_at
      animation_index = state.flapped_at.frame_index 6, 2, false if state.flapped_at
      sprite_name = "sprites/dragon_fly#{(animation_index || 0) + 1}.png"
      state.dragon_sprite = { x: state.x, y: state.y, w: 100, h: 80, path: sprite_name, angle: state.dy * 1.2 }
    else
      sprite_name = "sprites/dragon_die.png"
      state.dragon_sprite = { x: state.x, y: state.y, w: 100, h: 80, path: sprite_name, angle: state.dy * 1.2 }
      sprite_changed_elapsed    = state.death_at.elapsed_time - 1.seconds
      state.dragon_sprite.angle += (sprite_changed_elapsed ** 1.3) * state.death_fall_direction * -1
      state.dragon_sprite.x     += (sprite_changed_elapsed ** 1.2) * state.death_fall_direction
      state.dragon_sprite.y     += (sprite_changed_elapsed * 14 - sprite_changed_elapsed ** 1.6)
    end

    outputs.sprites << state.dragon_sprite
  end

  def render_flash
    return unless state.flash_at

    outputs.primitives << { **grid.rect.to_hash,
                            **white,
                            a: 255 * state.flash_at.ease(20, :flip) }.solid!

    state.flash_at = 0 if state.flash_at.elapsed_time > 20
  end

  def calc
    return unless state.scene == :game
    reset_game if state.countdown == 1
    state.countdown -= 1 and return if state.countdown > 0
    calc_walls
    calc_flap
    calc_game_over
  end

  def calc_walls
    state.walls.each { |w| w.x -= 8 }

    walls_count_before_removal = state.walls.length

    state.walls.reject! { |w| w.x < -100 }

    state.score += 1 if state.walls.count < walls_count_before_removal

    state.wall_countdown -= 1 and return if state.wall_countdown > 0

    state.walls << state.new_entity(:wall) do |w|
      w.x             = grid.right
      w.opening       = grid.top
                            .randomize(:ratio)
                            .greater(200)
                            .lesser(520)
      w.bottom_height = w.opening - state.wall_gap_size
      w.top_y         = w.opening + state.wall_gap_size
    end

    state.wall_countdown = state.wall_countdown_length
  end

  def calc_flap
    state.y += state.dy
    state.dy = state.dy.lesser state.flap_power
    state.dy -= state.gravity
    return if state.y < state.ceiling
    state.y  = state.ceiling
    state.dy = state.dy.lesser state.ceiling_flap_power
  end

  def calc_game_over
    return unless game_over?

    state.death_at = Kernel.tick_count
    state.death_from = state.walls.first
    state.death_fall_direction = -1
    state.death_fall_direction =  1 if state.x > state.death_from.x
    outputs.sounds << "sounds/hit-sound.wav"
    begin_countdown
  end

  def process_inputs
    process_inputs_menu
    process_inputs_game
  end

  def process_inputs_menu
    return unless state.scene == :menu

    changediff = inputs.keyboard.key_down.tab || inputs.controller_one.key_down.select
    if inputs.mouse.click
      p = inputs.mouse.click.point
      if (p.y >= 165) && (p.y < 200) && (p.x >= 500) && (p.x < 800)
        changediff = true
      end
    end

    if changediff
      case state.new_difficulty
      when :easy
        state.new_difficulty = :normal
      when :normal
        state.new_difficulty = :hard
      when :hard
        state.new_difficulty = :flappy
      when :flappy
        state.new_difficulty = :easy
      end
    end

    if inputs.keyboard.key_down.enter || inputs.controller_one.key_down.start || inputs.controller_one.key_down.a
      state.difficulty = state.new_difficulty
      change_to_scene :game
      reset_game false
      state.hi_score = 0
      begin_countdown
    end

    if inputs.keyboard.key_down.escape || (inputs.mouse.click && !changediff) || inputs.controller_one.key_down.b
      state.new_difficulty = state.difficulty
      change_to_scene :game
    end
  end

  def process_inputs_game
    return unless state.scene == :game

    clicked_menu = false
    if inputs.mouse.click
      p = inputs.mouse.click.point
      clicked_menu = (p.y >= 620) && (p.x < 275)
    end

    if clicked_menu || inputs.keyboard.key_down.escape || inputs.keyboard.key_down.enter || inputs.controller_one.key_down.start
      change_to_scene :menu
    elsif (inputs.mouse.down || inputs.mouse.click || inputs.keyboard.key_down.space || inputs.controller_one.key_down.a) && state.countdown == 0
      state.dy = 0
      state.dy += state.flap_power
      state.flapped_at = Kernel.tick_count
      outputs.sounds << "sounds/fly-sound.wav"
    end
  end

  def white
    { r: 255, g: 255, b: 255 }
  end

  def large_white_typeset
    { size_enum: 5, alignment_enum: 0, r: 255, g: 255, b: 255 }
  end

  def at_beginning?
    state.walls.count == 0
  end

  def dragon_collision_box
    state.dragon_sprite
         .scale_rect(1.0 - collision_forgiveness, 0.5, 0.5)
         .rect_shift_right(10)
         .rect_shift_up(state.dy * 2)
  end

  def game_over?
    return true if state.y <= 0.-(500 * collision_forgiveness) && !at_beginning?

    state.walls
        .flat_map { |w| w.sprites }
        .any? do |s|
          s && s.intersect_rect?(dragon_collision_box)
        end
  end

  def collision_forgiveness
    case state.difficulty
    when :easy
      0.9
    when :normal
      0.7
    when :hard
      0.5
    when :flappy
      0.3
    else
      0.9
    end
  end

  def countdown_text
    state.countdown ||= -1
    return ""          if state.countdown == 0
    return "GO!"       if state.countdown.idiv(60) == 0
    return "GAME OVER" if state.death_at
    return "READY?"
  end

  def begin_countdown
    state.countdown = 4.seconds
  end

  def score_text
    return ""                        unless state.countdown > 1.seconds
    return ""                        unless state.death_at
    return "SCORE: 0 (LOL)"          if state.score == 0
    return "HI SCORE: #{state.score}" if state.score == state.hi_score
    return "SCORE: #{state.score}"
  end

  def reset_game set_flash = true
    state.flash_at = Kernel.tick_count if set_flash
    state.walls = []
    state.y = 500
    state.dy = 0
    state.hi_score = state.hi_score.greater(state.score)
    state.score = 0
    state.wall_countdown = state.wall_countdown_length.fdiv(2)
    state.show_death = false
    state.death_at = nil
  end

  def change_to_scene scene
    state.scene = scene
    state.scene_at = Kernel.tick_count
    inputs.keyboard.clear
    inputs.controller_one.clear
  end
end

$flappy_dragon = FlappyDragon.new

def tick args
  $flappy_dragon.grid = args.grid
  $flappy_dragon.inputs = args.inputs
  $flappy_dragon.state = args.state
  $flappy_dragon.outputs = args.outputs
  $flappy_dragon.tick
end

Pong - main.rb link

# ./samples/99_genre_arcade/pong/app/main.rb
def tick args
  defaults args
  render args
  calc args
  input args
end

def defaults args
  args.state.ball ||= {
    debounce: 3 * 60,
    size: 10,
    size_half: 5,
    x: 640,
    y: 360,
    dx: 5.randomize(:sign),
    dy: 5.randomize(:sign)
  }

  args.state.paddle ||= {
    w: 10,
    h: 120
  }

  args.state.left_paddle  ||= { y: 360, score: 0 }
  args.state.right_paddle ||= { y: 360, score: 0 }
end

def render args
  render_center_line args
  render_scores args
  render_countdown args
  render_ball args
  render_paddles args
  render_instructions args
end

begin :render_methods
  def render_center_line args
    args.outputs.lines  << [640, 0, 640, 720]
  end

  def render_scores args
    args.outputs.labels << [
      { x: 320,
        y: 650,
        text: args.state.left_paddle.score,
        size_px: 40,
        anchor_x: 0.5,
        anchor_y: 0.5 },
      { x: 960,
        y: 650,
        text: args.state.right_paddle.score,
        size_px: 40,
        anchor_x: 0.5,
        anchor_y: 0.5 }
    ]
  end

  def render_countdown args
    return unless args.state.ball.debounce > 0
    args.outputs.labels << { x: 640,
                             y: 360,
                             text: "%.2f" % args.state.ball.debounce.fdiv(60),
                             size_px: 40,
                             anchor_x: 0.5,
                             anchor_y: 0.5 }
  end

  def render_ball args
    args.outputs.solids << solid_ball(args)
  end

  def render_paddles args
    args.outputs.solids << solid_left_paddle(args)
    args.outputs.solids << solid_right_paddle(args)
  end

  def render_instructions args
    args.outputs.labels << { x: 320,
                             y: 30,
                             text: "W and S keys to move left paddle.",
                             anchor_x: 0.5,
                             anchor_y: 0.5 }
    args.outputs.labels << { x: 920,
                             y: 30,
                             text: "O and L keys to move right paddle.",
                             anchor_x: 0.5,
                             anchor_y: 0.5 }
  end
end

def calc args
  args.state.ball.debounce -= 1 and return if args.state.ball.debounce > 0
  calc_move_ball args
  calc_collision_with_left_paddle args
  calc_collision_with_right_paddle args
  calc_collision_with_walls args
end

begin :calc_methods
  def calc_move_ball args
    args.state.ball.x += args.state.ball.dx
    args.state.ball.y += args.state.ball.dy
  end

  def calc_collision_with_left_paddle args
    if solid_left_paddle(args).intersect_rect? solid_ball(args)
      args.state.ball.dx *= -1
    elsif args.state.ball.x < 0
      args.state.right_paddle.score += 1
      calc_reset_round args
    end
  end

  def calc_collision_with_right_paddle args
    if solid_right_paddle(args).intersect_rect? solid_ball(args)
      args.state.ball.dx *= -1
    elsif args.state.ball.x > 1280
      args.state.left_paddle.score += 1
      calc_reset_round args
    end
  end

  def calc_collision_with_walls args
    if args.state.ball.y + args.state.ball.size_half > 720
      args.state.ball.y = 720 - args.state.ball.size_half
      args.state.ball.dy *= -1
    elsif args.state.ball.y - args.state.ball.size_half < 0
      args.state.ball.y = args.state.ball.size_half
      args.state.ball.dy *= -1
    end
  end

  def calc_reset_round args
    args.state.ball.x = 640
    args.state.ball.y = 360
    args.state.ball.dx = 5.randomize(:sign)
    args.state.ball.dy = 5.randomize(:sign)
    args.state.ball.debounce = 3 * 60
  end
end

def input args
  input_left_paddle args
  input_right_paddle args
end

def input_left_paddle args
  if args.inputs.controller_one.key_down.down  || args.inputs.keyboard.key_down.s
    args.state.left_paddle.y -= 40
  elsif args.inputs.controller_one.key_down.up || args.inputs.keyboard.key_down.w
    args.state.left_paddle.y += 40
  end
end

def input_right_paddle args
  if args.inputs.controller_two.key_down.down  || args.inputs.keyboard.key_down.l
    args.state.right_paddle.y -= 40
  elsif args.inputs.controller_two.key_down.up || args.inputs.keyboard.key_down.o
    args.state.right_paddle.y += 40
  end
end

def solid_ball args
  { x: args.state.ball.x,
    y: args.state.ball.y,
    w: args.state.ball.size,
    h: args.state.ball.size,
    anchor_x: 0.5,
    anchor_y: 0.5 }
end

def solid_left_paddle args
  { x: 0,
    y: args.state.left_paddle.y,
    w: args.state.paddle.w,
    h: args.state.paddle.h,
    anchor_y: 0.5 }
end

def solid_right_paddle args
  { x: 1280 - args.state.paddle.w,
    y: args.state.right_paddle.y,
    w: args.state.paddle.w,
    h: args.state.paddle.h,
    anchor_y: 0.5 }
end

Snakemoji - main.rb link

# ./samples/99_genre_arcade/snakemoji/app/main.rb
# coding: utf-8
################################
#  So I was working on a snake game while
#  learning DragonRuby, and at some point I had a thought
#  what if I use "😀" as a function name, surely it wont work right...?
#  RIGHT....?
#  BUT IT DID, IT WORKED
#  it all went downhill from then
#  Created by Anton K. (ai Doge)
#  https://gist.github.com/scorp200
#############LICENSE############
#  Feel free to use this anywhere and however you want
#  You can sell this to EA for $1,000,000 if you want, its completely free.
#  Just rememeber you are helping this... thing... to spread...
#  ALSO! I am not liable for any mental, physical or financial damage caused.
#############LICENSE############


class Array
  #Helper function
  def move! vector
    self.x += vector.x
    self.y += vector.y
    return self
  end

  #Helper function to draw snake body
  def draw! 🎮, 📺, color
    translate 📺.solids, 🎮.⛓, [self.x * 🎮.⚖️ + 🎮.🛶 / 2, self.y * 🎮.⚖️ + 🎮.🛶 / 2, 🎮.⚖️ - 🎮.🛶, 🎮.⚖️ - 🎮.🛶, color]
  end

  #This is where it all started, I was trying to find  good way to multiply a map by a number, * is already used so is **
  #I kept trying different combinations of symbols, when suddenly...
  def 😀 value
    self.map {|d| d * value}
  end
end

#Draw stuff with an offset
def translate output_collection, ⛓, what
  what.x += ⛓.x
  what.y += ⛓.y
  output_collection << what
end

BLUE = [33, 150, 243]
RED = [244, 67, 54]
GOLD = [255, 193, 7]
LAST = 0

def tick args
  defaults args.state
  render args.state, args.outputs
  input args.state, args.inputs
  update args.state
end

def update 🎮
  #Update every 10 frames
  if 🎮.tick_count.mod_zero? 10
    #Add new snake body piece at head's location
    🎮.🐍 << [*🎮.🤖]
    #Assign Next Direction to Direction
    🎮.🚗 = *🎮.🚦

    #Trim the snake a bit if its longer than current size
    if 🎮.🐍.length > 🎮.🛒
      🎮.🐍 = 🎮.🐍[-🎮.🛒..-1]
    end

    #Move the head in the Direction
    🎮.🤖.move! 🎮.🚗

    #If Head is outside the playing field, or inside snake's body restart game
    if 🎮.🤖.x < 0 || 🎮.🤖.x >= 🎮.🗺.x || 🎮.🤖.y < 0 || 🎮.🤖.y >= 🎮.🗺.y || 🎮.🚗 != [0, 0] && 🎮.🐍.any? {|s| s == 🎮.🤖}
      LAST = 🎮.💰
      🎮.as_hash.clear
      return
    end

    #If head lands on food add size and score
    if 🎮.🤖 == 🎮.🍎
      🎮.🛒 += 1
      🎮.💰 += (🎮.🛒 * 0.8).floor.to_i + 5
      spawn_🍎 🎮
      puts 🎮.🍎
    end
  end

  #Every second remove 1 point
  if 🎮.💰 > 0 && 🎮.tick_count.mod_zero?(60)
    🎮.💰 -= 1
  end
end

def spawn_🍎 🎮
  #Food
  🎮.🍎 ||= [*🎮.🤖]
  #Randomly spawns food inside the playing field, keep doing this if the food keeps landing on the snake's body
  while 🎮.🐍.any? {|s| s == 🎮.🍎} || 🎮.🍎 == 🎮.🤖 do
    🎮.🍎 = [rand(🎮.🗺.x), rand(🎮.🗺.y)]
  end
end

def render 🎮, 📺
  #Paint the background black
  📺.solids << [0, 0, 1280, 720, 0, 0, 0, 255]
  #Draw a border for the playing field
  translate 📺.borders, 🎮.⛓, [0, 0, 🎮.🗺.x * 🎮.⚖️, 🎮.🗺.y * 🎮.⚖️, 255, 255, 255]

  #Draw the snake's body
  🎮.🐍.map do |🐍| 🐍.draw! 🎮, 📺, BLUE end
  #Draw the head
  🎮.🤖.draw! 🎮, 📺, BLUE
  #Draw the food
  🎮.🍎.draw! 🎮, 📺, RED

  #Draw current score
  translate 📺.labels, 🎮.⛓, [5, 715, "Score: #{🎮.💰}", GOLD]
  #Draw your last score, if any
  translate 📺.labels, 🎮.⛓, [[*🎮.🤖.😀(🎮.⚖️)].move!([0, 🎮.⚖️ * 2]), "Your Last score is #{LAST}", 0, 1, GOLD] unless LAST == 0 || 🎮.🚗 != [0, 0]
  #Draw starting message, only if Direction is 0
  translate 📺.labels, 🎮.⛓, [🎮.🤖.😀(🎮.⚖️), "Press any Arrow key to start", 0, 1, GOLD] unless 🎮.🚗 != [0, 0]
end

def input 🎮, 🕹
  #Left and Right keyboard input, only change if X direction is 0
  if 🕹.keyboard.key_held.left && 🎮.🚗.x == 0
    🎮.🚦 = [-1, 0]
  elsif 🕹.keyboard.key_held.right && 🎮.🚗.x == 0
    🎮.🚦 = [1, 0]
  end

  #Up and Down keyboard input, only change if Y direction is 0
  if 🕹.keyboard.key_held.up && 🎮.🚗.y == 0
    🎮.🚦 = [0, 1]
  elsif 🕹.keyboard.key_held.down && 🎮.🚗.y == 0
    🎮.🚦 = [0, -1]
  end
end

def defaults 🎮
  #Playing field size
  🎮.🗺 ||= [20, 20]
  #Scale for drawing, screen height / Field height
  🎮.⚖️ ||= 720 / 🎮.🗺.y
  #Offset, offset all rendering to the center of the screen
  🎮.⛓ ||= [(1280 - 720).fdiv(2), 0]
  #Padding, make the snake body slightly smaller than the scale
  🎮.🛶 ||= (🎮.⚖️ * 0.2).to_i
  #Snake Size
  🎮.🛒 ||= 3
  #Snake head, the only part we are actually controlling
  🎮.🤖 ||= [🎮.🗺.x / 2, 🎮.🗺.y / 2]
  #Snake body map, follows the head
  🎮.🐍 ||= []
  #Direction the head moves to
  🎮.🚗 ||= [0, 0]
  #Next_Direction, during input check only change this variable and then when game updates asign this to Direction
  🎮.🚦 ||= [*🎮.🚗]
  #Your score
  🎮.💰 ||= 0
  #Spawns Food randomly
  spawn_🍎(🎮) unless 🎮.🍎
end

Solar System - main.rb link

# ./samples/99_genre_arcade/solar_system/app/main.rb
# Focused tutorial video: https://s3.amazonaws.com/s3.dragonruby.org/dragonruby-nddnug-workshop.mp4
# Workshop/Presentation which provides motivation for creating a game engine: https://www.youtube.com/watch?v=S3CFce1arC8

def defaults args
  args.outputs.background_color = [0, 0, 0]
  args.state.x ||= 640
  args.state.y ||= 360
  args.state.stars ||= 100.map do
    [1280 * rand, 720 * rand, rand.fdiv(10), 255 * rand, 255 * rand, 255 * rand]
  end

  args.state.sun ||= args.state.new_entity(:sun) do |s|
    s.s = 100
    s.path = 'sprites/sun.png'
  end

  args.state.planets = [
    [:mercury,   65,  5,          88],
    [:venus,    100, 10,         225],
    [:earth,    120, 10,         365],
    [:mars,     140,  8,         687],
    [:jupiter,  280, 30, 365 *  11.8],
    [:saturn,   350, 20, 365 *  29.5],
    [:uranus,   400, 15, 365 *    84],
    [:neptune,  440, 15, 365 * 164.8],
    [:pluto,    480,  5, 365 * 247.8],
  ].map do |name, distance, size, year_in_days|
    args.state.new_entity(name) do |p|
      p.path = "sprites/#{name}.png"
      p.distance = distance * 0.7
      p.s = size * 0.7
      p.year_in_days = year_in_days
    end
  end

  args.state.ship ||= args.state.new_entity(:ship) do |s|
    s.x = 1280 * rand
    s.y = 720 * rand
    s.angle = 0
  end
end

def to_sprite args, entity
  x = 0
  y = 0

  if entity.year_in_days
    day = Kernel.tick_count
    day_in_year = day % entity.year_in_days
    entity.random_start_day ||= day_in_year * rand
    percentage_of_year = day_in_year.fdiv(entity.year_in_days)
    angle = 365 * percentage_of_year
    x = angle.vector_x(entity.distance)
    y = angle.vector_y(entity.distance)
  end

  [640 + x - entity.s.half, 360 + y - entity.s.half, entity.s, entity.s, entity.path]
end

def render args
  args.outputs.solids << [0, 0, 1280, 720]

  args.outputs.sprites << args.state.stars.map do |x, y, _, r, g, b|
    [x, y, 10, 10, 'sprites/star.png', 0, 100, r, g, b]
  end

  args.outputs.sprites << to_sprite(args, args.state.sun)
  args.outputs.sprites << args.state.planets.map { |p| to_sprite args, p }
  args.outputs.sprites << [args.state.ship.x, args.state.ship.y, 20, 20, 'sprites/ship.png', args.state.ship.angle]
end

def calc args
  args.state.stars = args.state.stars.map do |x, y, speed, r, g, b|
    x += speed
    y += speed
    x = 0 if x > 1280
    y = 0 if y > 720
    [x, y, speed, r, g, b]
  end

  if Kernel.tick_count == 0
    args.audio[:bg_music] = {
      input: 'sounds/bg.ogg',
      looping: true
    }
  end
end

def process_inputs args
  if args.inputs.keyboard.left || args.inputs.controller_one.key_held.left
    args.state.ship.angle += 1
  elsif args.inputs.keyboard.right || args.inputs.controller_one.key_held.right
    args.state.ship.angle -= 1
  end

  if args.inputs.keyboard.up || args.inputs.controller_one.key_held.a
    args.state.ship.x += args.state.ship.angle.x_vector
    args.state.ship.y += args.state.ship.angle.y_vector
  end
end

def tick args
  defaults args
  render args
  calc args
  process_inputs args
end

def r
  $gtk.reset
end

Sound Golf - main.rb link

# ./samples/99_genre_arcade/sound_golf/app/main.rb
=begin

 APIs Listing that haven't been encountered in previous sample apps:

 - sample: Chooses random element from array.
   In this sample app, the target note is set by taking a sample from the collection
   of available notes.

 Reminders:
 - args.grid.(left|right|top|bottom): Pixel value for the boundaries of the virtual
   720 p screen (Dragon Ruby Game Toolkits's virtual resolution is always 1280x720).

 - args.state.new_entity: Used when we want to create a new object, like a sprite or button.
   For example, if we want to create a new button, we would declare it as a new entity and
   then define its properties.

 - String interpolation: Uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

 - args.outputs.labels: An array. The values generate a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGNMENT, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.

 - find_all: Finds all elements from a collection that meet a certain requirements (and excludes the ones that don't).

 - first: Returns the first element of an array.

 - inside_rect: Returns true or false depending on if the point is inside the rect.

 - to_sym: Returns symbol corresponding to string. Will create a symbol if it does
   not already exist.

=end

# This sample app allows users to test their musical skills by matching the piano sound that plays in each
# level to the correct note.

# Runs all the methods necessary for the game to function properly.
def tick args
  defaults args
  render args
  calc args
  input_mouse args
  tick_instructions args, "Sample app shows how to play sounds. args.outputs.sounds << \"path_to_wav.wav\""
end

# Sets default values and creates empty collections
# Initialization happens in the first frame only
def defaults args
  args.state.notes ||= []
  args.state.click_feedbacks ||= []
  args.state.current_level ||= 1
  args.state.times_wrong ||= 0 # when game starts, user hasn't guessed wrong yet
end

# Uses a label to display current level, and shows the score
# Creates a button to play the sample note, and displays the available notes that could be a potential match
def render args

  # grid.w_half positions the label in the horizontal center of the screen.
  args.outputs.labels << [args.grid.w_half, args.grid.top.shift_down(40), "Hole #{args.state.current_level} of 9", 0, 1, 0, 0, 0]

  render_score args # shows score on screen

  args.state.play_again_button ||= { x: 560, y: args.grid.h * 3 / 4 - 40, w: 160, h: 60, label: 'again' } # array definition, text/title
  args.state.play_note_button ||= { x: 560, y: args.grid.h * 3 / 4 - 40, w: 160, h: 60, label: 'play' }

  if args.state.game_over # if game is over, a "play again" button is shown
    # Calculations ensure that Play Again label is displayed in center of border
    # Remove calculations from y parameters and see what happens to border and label placement
    args.outputs.labels <<  [args.grid.w_half, args.grid.h * 3 / 4, "Play Again", 0, 1, 0, 0, 0] # outputs label
    args.outputs.borders << args.state.play_again_button # outputs border
  else # otherwise, if game is not over
    # Calculations ensure that label appears in center of border
    args.outputs.labels <<  [args.grid.w_half, args.grid.h * 3 / 4, "Play Note ##{args.state.current_level}", 0, 1, 0, 0, 0] # outputs label
    args.outputs.borders << args.state.play_note_button # outputs border
  end

  return if args.state.game_over # return if game is over

  args.outputs.labels <<   [args.grid.w_half, 400, "I think the note is a(n)...",  0, 1, 0, 0, 0] # outputs label

  # Shows all of the available notes that can be potential matches.
  available_notes.each_with_index do |note, i|
    args.state.notes[i] ||= piano_button(args, note, i + 1) # calls piano_button method on each note (creates label and border)
    args.outputs.labels <<   args.state.notes[i].label # outputs note on screen with a label and a border
    args.outputs.borders <<  args.state.notes[i].border
  end

  # Shows whether or not the user is correct by filling the screen with either red or green
  args.outputs.solids << args.state.click_feedbacks.map { |c| c.solid }
end

# Shows the score (number of times the user guesses wrong) onto the screen using labels.
def render_score args
  if args.state.times_wrong == 0 # if the user has guessed wrong zero times, the score is par
    args.outputs.labels << [args.grid.w_half, args.grid.top.shift_down(80), "Score: PAR", 0, 1, 0, 0, 0]
  else # otherwise, number of times the user has guessed wrong is shown
    args.outputs.labels << [args.grid.w_half, args.grid.top.shift_down(80), "Score: +#{args.state.times_wrong}", 0, 1, 0, 0, 0] # shows score using string interpolation
  end
end

# Sets the target note for the level and performs calculations on click_feedbacks.
def calc args
  args.state.target_note ||= available_notes.sample # chooses a note from available_notes collection as target note
  args.state.click_feedbacks.each    { |c| c.solid[-1] -= 5 } # remove this line and solid color will remain on screen indefinitely
  # comment this line out and the solid color will keep flashing on screen instead of being removed from click_feedbacks collection
  args.state.click_feedbacks.reject! { |c| c.solid[-1] <= 0 }
end

# Uses input from the user to play the target note, as well as the other notes that could be a potential match.
def input_mouse args
  return unless args.inputs.mouse.click # return unless the mouse is clicked

  # finds button that was clicked by user
  button_clicked = args.outputs.borders.find_all do |b| # go through borders collection to find all borders that meet requirements
    args.inputs.mouse.click.point.inside_rect? b # find button border that mouse was clicked inside of
  end.find_all { |b| b.is_a? Hash }.first # reject, return first element

  return unless button_clicked # return unless button_clicked as a value (a button was clicked)

  queue_click_feedback args, # calls queue_click_feedback method on the button that was clicked
                       button_clicked.x,
                       button_clicked.y,
                       button_clicked.w,
                       button_clicked.h,
                       150, 100, 200 # sets color of button to shade of purple

  if button_clicked[:label] == 'play' # if "play note" button is pressed
    args.outputs.sounds << "sounds/#{args.state.target_note}.wav" # sound of target note is output
  elsif button_clicked[:label] == 'again' # if "play game again" button is pressed
    args.state.target_note = nil # no target note
    args.state.current_level = 1 # starts at level 1 again
    args.state.times_wrong = 0 # starts off with 0 wrong guesses
    args.state.game_over = false # the game is not over (because it has just been restarted)
  else # otherwise if neither of those buttons were pressed
    args.outputs.sounds << "sounds/#{button_clicked[:label]}.wav" # sound of clicked note is played
    if button_clicked[:label] == args.state.target_note # if clicked note is target note
      args.state.target_note = nil # target note is emptied

      if args.state.current_level < 9 # if game hasn't reached level 9
        args.state.current_level += 1 # game goes to next level
      else # otherwise, if game has reached level 9
        args.state.game_over = true # the game is over
      end

      queue_click_feedback args, 0, 0, args.grid.w, args.grid.h, 100, 200, 100 # green shown if user guesses correctly
    else # otherwise, if clicked note is not target note
      args.state.times_wrong += 1 # increments times user guessed wrong
      queue_click_feedback args, 0, 0, args.grid.w, args.grid.h, 200, 100, 100 # red shown is user guesses wrong
    end
  end
end

# Creates a collection of all of the available notes as symbols
def available_notes
  [:C3, :D3, :E3, :F3, :G3, :A3, :B3, :C4]
end

# Creates buttons for each note, and sets a label (the note's name) and border for each note's button.
def piano_button args, note, position
  args.state.new_entity(:button) do |b| # declares button as new entity
    b.label  =  [460 + 40.mult(position), args.grid.h * 0.4, "#{note}", 0, 1, 0, 0, 0] # label definition
    b.border =  { x: 460 + 40.mult(position) - 20, y: args.grid.h * 0.4 - 32, w: 40, h: 40, label: note } # border definition, text/title; 20 subtracted so label is in center of border
  end
end

# Color of click feedback changes depending on what button was clicked, and whether the guess is right or wrong
# If a button is clicked, the inside of button is purple (see input_mouse method)
# If correct note is clicked, screen turns green
# If incorrect note is clicked, screen turns red (again, see input_mouse method)
def queue_click_feedback args, x, y, w, h, *color
  args.state.click_feedbacks << args.state.new_entity(:click_feedback) do |c| # declares feedback as new entity
    c.solid =  [x, y, w, h, *color, 255] # sets color
  end
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Squares - main.rb link

# ./samples/99_genre_arcade/squares/app/main.rb
# game concept from: https://youtu.be/Tz-AinJGDIM

# This class encapsulates the logic of a button that pulses when clicked.
# It is used in the StartScene and GameOverScene classes.
class PulseButton
  # a block is passed into the constructor and is called when the button is clicked,
  # and after the pulse animation is complete
  def initialize rect, text, &on_click
    @rect = rect
    @text = text
    @on_click = on_click
    @pulse_animation_spline = [[0.0, 0.90, 1.0, 1.0], [1.0, 0.10, 0.0, 0.0]]
    @duration = 10
  end

  # the button is ticked every frame and check to see if the mouse
  # intersects the button's bounding box.
  # if it does, then pertinent information is stored in the @clicked_at variable
  # which is used to calculate the pulse animation
  def tick tick_count, mouse
    @tick_count = tick_count

    if @clicked_at && @clicked_at.elapsed_time > @duration
      @clicked_at = nil
      @on_click.call
    end

    return if !mouse.click
    return if !mouse.inside_rect? @rect
    @clicked_at = tick_count
  end

  # this function returns an array of primitives that can be rendered
  def prefab easing
    # calculate the percentage of the pulse animation that has completed
    # and use the percentage to compute the size and position of the button
    perc = if @clicked_at
             easing.ease_spline @clicked_at, @tick_count, @duration, @pulse_animation_spline
           else
             0
           end

    rect = { x: @rect.x - 50 * perc / 2,
             y: @rect.y - 50 * perc / 2,
             w: @rect.w + 50 * perc,
             h: @rect.h + 50 * perc }

    point = { x: @rect.x + @rect.w / 2, y: @rect.y + @rect.h / 2 }
    [
      { **rect, path: :pixel },
      { **point, text: @text, size_px: 32, anchor_x: 0.5, anchor_y: 0.5 }
    ]
  end
end

# the start scene is loaded when the game is started
# it contains a PulseButton that starts the game by setting the next_scene to :game and
# setting the started_at time
class StartScene
  attr_gtk

  def initialize args
    self.args = args
    @play_button = PulseButton.new layout.rect(row: 6, col: 11, w: 2, h: 2), "play" do
      state.next_scene = :game
      state.events.game_started_at = Kernel.tick_count
      state.events.game_over_at = nil
    end
  end

  def tick
    return if state.current_scene != :start
    @play_button.tick Kernel.tick_count, inputs.mouse
    outputs[:start_scene].labels << layout.point(row: 0, col: 12).merge(text: "Squares", anchor_x: 0.5, anchor_y: 0.5, size_px: 64)
    outputs[:start_scene].primitives << @play_button.prefab(easing)
  end
end

# the game over scene is displayed when the game is over
# it contains a PulseButton that restarts the game by setting the next_scene to :game and
# setting the game_retried_at time
class GameOverScene
  attr_gtk

  def initialize args
    self.args = args
    @replay_button = PulseButton.new layout.rect(row: 6, col: 11, w: 2, h: 2), "replay" do
      state.next_scene = :game
      state.events.game_retried_at = Kernel.tick_count
      state.events.game_over_at = nil
    end
  end

  def tick
    return if state.current_scene != :game_over
    @replay_button.tick Kernel.tick_count, inputs.mouse
    outputs[:game_over_scene].labels << layout.point(row: 0, col: 12).merge(text: "Game Over", anchor_x: 0.5, anchor_y: 0.5, size_px: 64)
    outputs[:game_over_scene].primitives << @replay_button.prefab(easing)

    rect = layout.point row: 2, col: 12
    outputs[:game_over_scene].primitives << rect.merge(text: state.score_last_game, anchor_x: 0.5, anchor_y: 0.5, size_px: 128, **state.red_color)

    rect = layout.point row: 4, col: 12
    outputs[:game_over_scene].primitives << rect.merge(text: "BEST #{state.best_score}", anchor_x: 0.5, anchor_y: 0.5, size_px: 64, **state.gray_color)
  end
end

# the game scene contains the game logic
class GameScene
  attr_gtk

  def tick
    defaults
    calc
    render
  end

  def defaults
    return if started_at != Kernel.tick_count

    # initalization of scene_state variables for the game
    scene_state.score_animation_spline = [[0.0, 0.66, 1.0, 1.0], [1.0, 0.33, 0.0, 0.0]]
    scene_state.launch_particle_queue = []
    scene_state.scale_down_particles_queue = []
    scene_state.score = 0
    scene_state.square_number = 1
    scene_state.squares = []
    scene_state.square_spawn_rate = 60
    scene_state.movement_outer_rect = layout.rect(row: 11, col: 7, w: 10, h: 1).merge(path: :pixel, **state.gray_color)

    scene_state.player = { x: geometry.rect_center_point(movement_outer_rect).x,
                           y: movement_outer_rect.y,
                           w: movement_outer_rect.h,
                           h: movement_outer_rect.h,
                           path: :pixel,
                           movement_direction: 1,
                           movement_speed: 8,
                           **args.state.red_color }

    scene_state.movement_inner_rect = { x: movement_outer_rect.x + player.w * 1,
                                        y: movement_outer_rect.y,
                                        w: movement_outer_rect.w - player.w * 2,
                                        h: movement_outer_rect.h }
  end

  def calc
    calc_game_over_at
    calc_particles

    # game logic is only calculated if the current scene is :game
    return if state.current_scene != :game

    # we don't want the game loop to start for half a second after the game starts
    # this gives enough time for the game scene to animate in
    return if !started_at || started_at.elapsed_time <= 30

    calc_player
    calc_squares
    calc_game_over
  end

  # this function calculates the point in the time the game is over
  # an intermediary variable stored in scene_state.death_at is consulted
  # before transitioning to the game over scene to ensure that particle animations
  # have enough time to complete before the game over scene is rendered
  def calc_game_over_at
    return if !death_at
    return if death_at.elapsed_time < 120
    state.events.game_over_at ||= Kernel.tick_count
  end

  # this function calculates the particles
  # there are two queues of particles that are processed
  # the launch_particle_queue contains particles that are launched when the player is hit
  # the scale_down_particles_queue contains particles that need to be scaled down
  def calc_particles
    return if !started_at

    scene_state.launch_particle_queue.each do |p|
      p.x += p.launch_angle.vector_x * p.speed
      p.y += p.launch_angle.vector_y * p.speed
      p.speed *= 0.90
      p.d_a ||= 1
      p.a -= 1 * p.d_a
      p.d_a *= 1.1
    end

    scene_state.launch_particle_queue.reject! { |p| p.a <= 0 }

    scene_state.scale_down_particles_queue.each do |p|
      next if p.start_at > Kernel.tick_count
      p.scale_speed = p.scale_speed.abs
      p.x += p.scale_speed
      p.y += p.scale_speed
      p.w -= p.scale_speed * 2
      p.h -= p.scale_speed * 2
    end

    scene_state.scale_down_particles_queue.reject! { |p| p.w <= 0 }
  end

  def render
    return if !started_at
    scene_outputs.primitives << game_scene_score_prefab
    scene_outputs.primitives << scene_state.movement_outer_rect.merge(a: 128)
    scene_outputs.primitives << squares
    scene_outputs.primitives << player_prefab
    scene_outputs.primitives << scene_state.launch_particle_queue
    scene_outputs.primitives << scene_state.scale_down_particles_queue
  end

  # this function returns the rendering primitive for the score
  def game_scene_score_prefab
    score = if death_at
              state.score_last_game
            else
              scene_state.score
            end

    label_scale_prec = easing.ease_spline(scene_state.score_at || 0, Kernel.tick_count, 15, scene_state.score_animation_spline)
    rect = layout.point row: 4, col: 12
    rect.merge(text: score, anchor_x: 0.5, anchor_y: 0.5, size_px: 128 + 50 * label_scale_prec, **state.gray_color)
  end

  def player_prefab
    return nil if death_at
    scale_perc = easing.ease(started_at + 30, Kernel.tick_count, 15, :smooth_start_quad, :flip)
    player.merge(x: player.x - player.w / 2 * scale_perc, y: player.y + player.h / 2 * scale_perc,
                 w: player.w * (1 - scale_perc), h: player.h * (1 - scale_perc))
  end

  # controls the player movement and change in direction of the player when the mouse is clicked
  def calc_player
    player.x += player.movement_speed * player.movement_direction
    player.movement_direction *= -1 if !geometry.inside_rect? player, scene_state.movement_outer_rect
    return if !inputs.mouse.click
    return if !geometry.inside_rect? player, movement_inner_rect
    player.movement_direction = -player.movement_direction
  end

  # computes the squares movement
  def calc_squares
    squares << new_square if Kernel.tick_count.zmod? scene_state.square_spawn_rate

    squares.each do |square|
      square.angle += 1
      square.x += square.dx
      square.y += square.dy
    end

    squares.reject! { |square| (square.y + square.h) < 0 }
  end

  # determines if score should be incremented or if the game should be over
  def calc_game_over
    collision = geometry.find_intersect_rect player, squares
    return if !collision
    if collision.type == :good
      scene_state.score += 1
      scene_state.score_at = Kernel.tick_count
      scene_state.scale_down_particles_queue << collision.merge(start_at: Kernel.tick_count, scale_speed: -2)
      squares.delete collision
    else
      generate_death_particles
      state.best_score = scene_state.score if scene_state.score > state.best_score
      squares.clear
      state.score_last_game = scene_state.score
      scene_state.score = 0
      scene_state.square_number = 1
      scene_state.death_at = Kernel.tick_count
      state.next_scene = :game_over
    end
  end

  # this function generates the particles when the player is hit
  def generate_death_particles
    square_particles = squares.map { |b| b.merge(start_at: Kernel.tick_count + 60, scale_speed: -1) }

    scene_state.scale_down_particles_queue.concat square_particles

    # generate 12 particles with random size, launch angle and speed
    player_particles = 12.map do
      size = rand * player.h * 0.5 + 10
      player.merge(w: size, h: size, a: 255, launch_angle: rand * 180, speed: 10 + rand * 50)
    end

    scene_state.launch_particle_queue.concat player_particles
  end

  # this function returns a new square
  # every 5th square is a good square (increases the score)
  def new_square
    x = movement_inner_rect.x + rand * movement_inner_rect.w

    dx = if x > geometry.rect_center_point(movement_inner_rect).x
           -0.9
         else
           0.9
         end

    if scene_state.square_number.zmod? 5
      type = :good
      color = state.red_color
    else
      type = :bad
      color = { r: 0, g: 0, b: 0 }
    end

    scene_state.square_number += 1

    { x: x - 16, y: 1300, w: 32, h: 32,
      dx: dx, dy: -5,
      angle: 0, type: type,
      path: :pixel, **color }
  end

  # death_at is the point in time that the player died
  # the death_at value is an intermediary variable that is used to calculate the death animation
  # before setting state.game_over_at
  def death_at
    return nil if !scene_state.death_at
    return nil if scene_state.death_at < started_at
    scene_state.death_at
  end

  # started_at is the point in time that the player started (or retried) the game
  def started_at
    state.events.game_retried_at || state.events.game_started_at
  end

  def scene_state
    state.game_scene ||= {}
  end

  def scene_outputs
    outputs[:game_scene]
  end

  def player
    scene_state.player
  end

  def movement_outer_rect
    scene_state.movement_outer_rect
  end

  def movement_inner_rect
    scene_state.movement_inner_rect
  end

  def squares
    scene_state.squares
  end
end

class RootScene
  attr_gtk

  def initialize args
    self.args = args
    @start_scene = StartScene.new args
    @game_scene = GameScene.new
    @game_over_scene = GameOverScene.new args
  end

  def tick
    outputs.background_color = [237, 237, 237]
    init_game
    state.scene_at_tick_start = state.current_scene
    tick_start_scene
    tick_game_scene
    tick_game_over_scene
    render_scenes
    transition_to_next_scene
  end

  def tick_start_scene
    @start_scene.args = args
    @start_scene.tick
  end

  def tick_game_scene
    @game_scene.args = args
    @game_scene.tick
  end

  def tick_game_over_scene
    @game_over_scene.args = args
    @game_over_scene.tick
  end

  # initlalization of game state that is shared between scenes
  def init_game
    return if Kernel.tick_count != 0

    state.current_scene = :start

    state.red_color = { r: 222, g: 63, b: 66 }
    state.gray_color = { r: 128, g: 128, b: 128 }

    state.events ||= {
      game_over_at: nil,
      game_started_at: nil,
      game_retried_at: nil
    }

    state.score_last_game = 0
    state.best_score = 0
    state.viewport = { x: 0, y: 0, w: 1280, h: 720 }
  end

  def transition_to_next_scene
    if state.scene_at_tick_start != state.current_scene
      raise "state.current_scene was changed during the tick. This is not allowed (use state.next_scene to set the scene to transfer to)."
    end

    return if !state.next_scene
    state.current_scene = state.next_scene
    state.next_scene = nil
  end

  # this function renders the scenes with a transition effect
  # based off of timestamps stored in state.events
  def render_scenes
    if state.events.game_over_at
      in_y = transition_in_y state.events.game_over_at
      out_y = transition_out_y state.events.game_over_at
      outputs.sprites << state.viewport.merge(y: out_y, path: :game_scene)
      outputs.sprites << state.viewport.merge(y: in_y, path: :game_over_scene)
    elsif state.events.game_retried_at
      in_y = transition_in_y state.events.game_retried_at
      out_y = transition_out_y state.events.game_retried_at
      outputs.sprites << state.viewport.merge(y: out_y, path: :game_over_scene)
      outputs.sprites << state.viewport.merge(y: in_y, path: :game_scene)
    elsif state.events.game_started_at
      in_y = transition_in_y state.events.game_started_at
      out_y = transition_out_y state.events.game_started_at
      outputs.sprites << state.viewport.merge(y: out_y, path: :start_scene)
      outputs.sprites << state.viewport.merge(y: in_y, path: :game_scene)
    else
      in_y = transition_in_y 0
      start_scene_perc = easing.ease(0, Kernel.tick_count, 30, :smooth_stop_quad, :flip)
      outputs.sprites << state.viewport.merge(y: in_y, path: :start_scene)
    end
  end

  def transition_in_y start_at
    easing.ease(start_at, Kernel.tick_count, 30, :smooth_stop_quad, :flip) * -1280
  end

  def transition_out_y start_at
    easing.ease(start_at, Kernel.tick_count, 30, :smooth_stop_quad) * 1280
  end
end

def tick args
  $game ||= RootScene.new args
  $game.args = args
  $game.tick

  if args.inputs.keyboard.key_down.forward_slash
    @show_fps = !@show_fps
  end
  if @show_fps
    args.outputs.primitives << args.gtk.current_framerate_primitives
  end
end

$gtk.reset

Twinstick - main.rb link

# ./samples/99_genre_arcade/twinstick/app/main.rb
def tick args
  args.state.player         ||= {x: 600, y: 320, w: 80, h: 80, path: 'sprites/circle-white.png', vx: 0, vy: 0, health: 10, cooldown: 0, score: 0}
  args.state.enemies        ||= []
  args.state.player_bullets ||= []
  spawn_enemies args
  kill_enemies args
  move_enemies args
  move_bullets args
  move_player args
  fire_player args
  args.state.player[:r] = args.state.player[:g] = args.state.player[:b] = (args.state.player[:health] * 25.5).clamp(0, 255)
  label_color           = args.state.player[:health] <= 5 ? 255 : 0
  args.outputs.labels << [
      {
          x: args.state.player.x + 40, y: args.state.player.y + 60, alignment_enum: 1, text: "#{args.state.player[:health]} HP",
          r: label_color, g: label_color, b: label_color
      }, {
          x: args.state.player.x + 40, y: args.state.player.y + 40, alignment_enum: 1, text: "#{args.state.player[:score]} PTS",
          r: label_color, g: label_color, b: label_color, size_enum: 2 - args.state.player[:score].to_s.length,
      }
  ]
  args.outputs.sprites << [args.state.player, args.state.enemies, args.state.player_bullets]
  args.state.clear! if args.state.player[:health] < 0 # Reset the game if the player's health drops below zero
end

def spawn_enemies args
  # Spawn enemies more frequently as the player's score increases.
  if rand < (100+args.state.player[:score])/(10000 + args.state.player[:score]) || Kernel.tick_count.zero?
    theta = rand * Math::PI * 2
    args.state.enemies << {
        x: 600 + Math.cos(theta) * 800, y: 320 + Math.sin(theta) * 800, w: 80, h: 80, path: 'sprites/circle-white.png',
        r: (256 * rand).floor, g: (256 * rand).floor, b: (256 * rand).floor
    }
  end
end

def kill_enemies args
  args.state.enemies.reject! do |enemy|
    # Check if enemy and player are within 80 pixels of each other (i.e. overlapping)
    if 6400 > (enemy.x - args.state.player.x) ** 2 + (enemy.y - args.state.player.y) ** 2
      # Enemy is touching player. Kill enemy, and reduce player HP by 1.
      args.state.player[:health] -= 1
    else
      args.state.player_bullets.any? do |bullet|
        # Check if enemy and bullet are within 50 pixels of each other (i.e. overlapping)
        if 2500 > (enemy.x - bullet.x + 30) ** 2 + (enemy.y - bullet.y + 30) ** 2
          # Increase player health by one for each enemy killed by a bullet after the first enemy, up to a maximum of 10 HP
          args.state.player[:health] += 1 if args.state.player[:health] < 10 && bullet[:kills] > 0
          # Keep track of how many enemies have been killed by this particular bullet
          bullet[:kills]             += 1
          # Earn more points by killing multiple enemies with one shot.
          args.state.player[:score]  += bullet[:kills]
        end
      end
    end
  end
end

def move_enemies args
  args.state.enemies.each do |enemy|
    # Get the angle from the enemy to the player
    theta   = Math.atan2(enemy.y - args.state.player.y, enemy.x - args.state.player.x)
    # Convert the angle to a vector pointing at the player
    dx, dy  = theta.to_degrees.vector 5
    # Move the enemy towards thr player
    enemy.x -= dx
    enemy.y -= dy
  end
end

def move_bullets args
  args.state.player_bullets.each do |bullet|
    # Move the bullets according to the bullet's velocity
    bullet.x += bullet[:vx]
    bullet.y += bullet[:vy]
  end
  args.state.player_bullets.reject! do |bullet|
    # Despawn bullets that are outside the screen area
    bullet.x < -20 || bullet.y < -20 || bullet.x > 1300 || bullet.y > 740
  end
end

def move_player args
  # Get the currently held direction.
  dx, dy                 = move_directional_vector args
  # Take the weighted average of the old velocities and the desired velocities.
  # Since move_directional_vector returns values between -1 and 1,
  #   and we want to limit the speed to 7.5, we multiply dx and dy by 7.5*0.1 to get 0.75
  args.state.player[:vx] = args.state.player[:vx] * 0.9 + dx * 0.75
  args.state.player[:vy] = args.state.player[:vy] * 0.9 + dy * 0.75
  # Move the player
  args.state.player.x    += args.state.player[:vx]
  args.state.player.y    += args.state.player[:vy]
  # If the player is about to go out of bounds, put them back in bounds.
  args.state.player.x    = args.state.player.x.clamp(0, 1201)
  args.state.player.y    = args.state.player.y.clamp(0, 640)
end


def fire_player args
  # Reduce the firing cooldown each tick
  args.state.player[:cooldown] -= 1
  # If the player is allowed to fire
  if args.state.player[:cooldown] <= 0
    dx, dy = shoot_directional_vector args # Get the bullet velocity
    return if dx == 0 && dy == 0 # If the velocity is zero, the player doesn't want to fire. Therefore, we just return early.
    # Add a new bullet to the list of player bullets.
    args.state.player_bullets << {
        x:     args.state.player.x + 30 + 40 * dx,
        y:     args.state.player.y + 30 + 40 * dy,
        w:     20, h: 20,
        path:  'sprites/circle-white.png',
        r:     0, g: 0, b: 0,
        vx:    10 * dx + args.state.player[:vx] / 7.5, vy: 10 * dy + args.state.player[:vy] / 7.5, # Factor in a bit of the player's velocity
        kills: 0
    }
    args.state.player[:cooldown] = 30 # Reset the cooldown
  end
end

# Custom function for getting a directional vector just for movement using WASD
def move_directional_vector args
  dx = 0
  dx += 1 if args.inputs.keyboard.d
  dx -= 1 if args.inputs.keyboard.a
  dy = 0
  dy += 1 if args.inputs.keyboard.w
  dy -= 1 if args.inputs.keyboard.s
  if dx != 0 && dy != 0
    dx *= 0.7071
    dy *= 0.7071
  end
  [dx, dy]
end

# Custom function for getting a directional vector just for shooting using the arrow keys
def shoot_directional_vector args
  dx = 0
  dx += 1 if args.inputs.keyboard.key_down.right || args.inputs.keyboard.key_held.right
  dx -= 1 if args.inputs.keyboard.key_down.left || args.inputs.keyboard.key_held.left
  dy = 0
  dy += 1 if args.inputs.keyboard.key_down.up || args.inputs.keyboard.key_held.up
  dy -= 1 if args.inputs.keyboard.key_down.down || args.inputs.keyboard.key_held.down
  if dx != 0 && dy != 0
    dx *= 0.7071
    dy *= 0.7071
  end
  [dx, dy]
end

Genre Board Game link

Fifteen Puzzle - main.rb link

# ./samples/99_genre_board_game/01_fifteen_puzzle/app/main.rb
class Game
  attr_gtk

  def tick
    defaults
    calc
    render
  end

  def defaults
    # set a reliable seed when not in production so the
    # saved replay works correctly
    srand 0 if Kernel.tick_count == 0 && !gtk.production?

    # set rendering positions/properties
    state.cell_size     ||= 64
    state.left_margin   ||= (grid.w - 4 * state.cell_size) / 2
    state.bottom_margin ||= (grid.h - 4 * state.cell_size) / 2

    # if the board isn't initialized
    if !state.board || state.win
      # generate a solvable board
      state.board = solvable_board
      state.win = false
    end
  end

  def solvable_board
    # create a random board with cells of the
    # following format:
    # {
    #   value: 1,
    #   loc: { row: 0, col: 0 },
    #   previous_loc: { row: 0, col: 0 },
    #   clicked_at: 0
    # }
    results = 16.map_with_index do |i|
      { value: i + 1 }
    end.sort_by do |cell|
      rand
    end.map_with_index do |cell, index|
      row = index.idiv 4
      col = index % 4
      cell.merge loc: { row: row, col: col },
                 previous_loc: { row: row, col: col },
                 clicked_at: 0
    end

    # determine if the board is solvable
    # by counting the number of inversions
    # (a board is solvable if the number of inversions is even)
    solvable = number_of_inversions(results).even?

    # recursively call this method until a solvable board is generated
    return solvable_board if !solvable

    return results
  end

  def number_of_inversions board
    # get the number of rows
    number_of_rows = board.map { |cell| cell.loc.row }.uniq.count

    results = 0

    # for each row
    number_of_rows.times_with_index do |row|
      # find all the cells in the row
      # and count the number of inversions for that single row
      inversions_in_row = board.find_all { |cell| cell.loc.row == row }
                               .map { |cell| cell.value }
                               .each_cons(2)
                               .map { |cell, next_cell| cell > next_cell ? 1 : 0 }
                               .sum

      # add the number of inversions for that row to the total
      results += inversions_in_row
    end

    # return the total number of inversions
    results
  end

  def render
    outputs.sprites << board.map do |cell|
      # render the board centered in the middle of the screen
      prefab = cell_prefab cell
      prefab.merge x: state.left_margin + prefab.x, y: state.bottom_margin + prefab.y
    end

    # render the win message
    if state.won_at && state.won_at.elapsed_time < 180
      # define a bezier spline that will be used to
      # fade in the win message stay visible for a little bit
      # then fade out
      spline = [
        [  0, 0.25, 0.75, 1.0],
        [1.0, 1.0,  1.0,  1.0],
        [1.0, 0.75, 0.25,   0]
      ]

      alpha_percentage = args.easing.ease_spline state.won_at,
                                                 Kernel.tick_count,
                                                 180,
                                                 spline

      outputs.sprites << {
        x: 0,
        y: grid.h.half - 32,
        w: grid.w,
        h: 64,
        path: :pixel,
        r: 0,
        g: 0,
        b: 0,
        a: 255 * alpha_percentage,
      }

      outputs.labels << {
        x: grid.w.half,
        y: grid.h.half,
        text: "You won!",
        a: 255 * alpha_percentage,
        alignment_enum: 1,
        vertical_alignment_enum: 1,
        size_enum: 10,
        r: 255,
        g: 255,
        b: 255
      }
    end
  end

  def calc
    calc_input
    calc_win
  end

  def calc_input
    # return if the mouse isn't clicked
    return if !inputs.mouse.click

    # determine which cell was clicked
    clicked_cell = board.find do |cell|
      mouse_rect = {
        x: inputs.mouse.x - state.left_margin,
        y: inputs.mouse.y - state.bottom_margin,
        w: 1,
        h: 1,
      }
      mouse_rect.intersect_rect? render_rect(cell.loc)
    end

    # return if no cell was clicked
    return if !clicked_cell

    # find the empty cell
    empty_cell = board.find do |cell|
      cell.value == 16
    end

    # find the clicked cell's neighbors
    clicked_cell_neighbors = neighbors clicked_cell

    # return if the cell's neighbors doesn't include the empty cell
    return if !clicked_cell_neighbors.include?(empty_cell)

    # otherwise swap the clicked cell with the empty cell
    swap_with_empty clicked_cell, empty_cell
  end

  def calc_win
    sorted_values = board.sort_by { |cell| (cell.loc.col + 1) + (16 - (cell.loc.row * 4)) }
                         .map { |cell| cell.value }

    state.win = sorted_values == (1..16).to_a

    state.won_at ||= Kernel.tick_count if state.win
  end

  def swap_with_empty cell, empty
    # take not of the cell's current location (within previous_loc)
    cell.previous_loc = cell.loc

    # swap the cell's location with the empty cell's location and vice versa
    cell.loc, empty.loc = empty.loc, cell.loc

    # take note of the current tick count (which will be used for animation)
    cell.clicked_at = Kernel.tick_count
  end

  def cell_prefab cell
    # determine the percentage for the lerp that should be performed
    percentage = if cell.clicked_at
                   easing.ease cell.clicked_at, Kernel.tick_count, 15, :smooth_stop_quint, :flip
                 else
                   1
                 end

    # determine the cell's current render location
    cell_rect = render_rect cell.loc

    # determine the cell's previous render location
    previous_rect = render_rect cell.previous_loc

    # compute the difference between the current and previous render locations
    x = cell_rect.x + (previous_rect.x - cell_rect.x) * percentage
    y = cell_rect.y + (previous_rect.y - cell_rect.y) * percentage

    # return the cell prefab
    { x: x,
      y: y,
      w: state.cell_size,
      h: state.cell_size,
      path: "sprites/pieces/#{cell.value}.png" }
  end

  # helper method to determine the render location of a cell in local space
  # which excludes the margins
  def render_rect loc
    {
      x: loc.col * state.cell_size,
      y: loc.row * state.cell_size,
      w: state.cell_size,
      h: state.cell_size,
    }
  end

  # helper methods to determine neighbors of a cell
  def neighbors cell
    [
      above_cell(cell),
      below_cell(cell),
      left_cell(cell),
      right_cell(cell),
    ]
  end

  def below_cell cell
    find_cell cell, -1, 0
  end

  def above_cell cell
    find_cell cell, 1, 0
  end

  def left_cell cell
    find_cell cell, 0, -1
  end

  def right_cell cell
    find_cell cell, 0, 1
  end

  def find_cell cell, d_row, d_col
    board.find do |other_cell|
      cell.loc.row == other_cell.loc.row + d_row &&
      cell.loc.col == other_cell.loc.col + d_col
    end
  end

  def board
    state.board
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

$gtk.reset

Genre Boss Battle link

Boss Battle Game Jam - main.rb link

# ./samples/99_genre_boss_battle/boss_battle_game_jam/app/main.rb
class Game
  attr_gtk

  def tick
    defaults
    input
    calc
    render
  end

  def defaults
    state.high_score          ||= 0
    state.damage_render_queue ||= []
    game_reset if Kernel.tick_count == 0 || state.start_new_game
  end

  def game_reset
    state.start_new_game      = false
    state.game_over           = false
    state.game_over_countdown = nil

    state.player.tile_size          = 64
    state.player.speed              = 4
    state.player.slash_frames       = 15
    state.player.hp                 = 3
    state.player.damaged_at         = -1000
    state.player.x                  = 50
    state.player.y                  = 400
    state.player.dir_x              =  1
    state.player.dir_y              = -1
    state.player.is_moving          = false

    state.boss.damage               = 0
    state.boss.x                    = 800
    state.boss.y                    = 400
    state.boss.w                    = 256
    state.boss.h                    = 256
    state.boss.target_x             = 800
    state.boss.target_y             = 400
    state.boss.attack_cooldown      = 600
  end

  def input
    return if state.game_over

    player.is_moving = false

    if input_attack?
      player.slash_at = Kernel.tick_count
    end

    if !player_attacking?
      vector = inputs.directional_vector
      if vector
        next_player_x = player.x + vector.x * player.speed
        next_player_y = player.y + vector.y * player.speed
        player.x = next_player_x if player_x_inside_stage? next_player_x
        player.y = next_player_y if player_y_inside_stage? next_player_y

        player.is_moving = true

        player.dir_x = if vector.x < 0
                         -1
                       elsif vector.x > 0
                         1
                       else
                         player.dir_x
                       end

        player.dir_y = if vector.y < 0
                         -1
                       elsif vector.y > 0
                         1
                       else
                         player.dir_y
                       end
      end
    end
  end

  def input_attack?
    inputs.controller_one.key_down.a ||
    inputs.controller_one.key_down.b ||
    inputs.keyboard.key_down.j
  end

  def calc
    calc_player
    calc_boss
    calc_damage_render_queue
    calc_high_score
    calc_game_over
  end

  def calc_player
    player.slash_at = nil if !player_attacking?
    return unless player_slash_can_damage?
    if player_hit_box.intersect_rect? boss_hurt_box
      boss.damage += 1
      queue_damage player_hit_box.x + player_hit_box.w / 2 * player.dir_x,
                   player_hit_box.y + player_hit_box.h / 2
    end
  end

  def calc_boss
    boss.attack_cooldown -= 1
    if boss.attack_cooldown < 0
      boss.target_x = player.x - 100
      boss.target_y = player.y - 100
      boss.attack_cooldown = if    boss.damage > 200
                               200
                             elsif boss.damage > 150
                               300
                             elsif boss.damage > 100
                               400
                             elsif boss.damage > 50
                               500
                             else
                               600
                             end
    end

    dx = boss.target_x - boss.x
    dy = boss.target_y - boss.y
    boss.x += dx * 0.25 ** 2
    boss.y += dy * 0.25 ** 2

    if boss.intersect_rect?(player_hurt_box) && player.damaged_at.elapsed?(120)
      player.damaged_at = Kernel.tick_count
      player.hp -= 1
      player.hp  = 0 if player.hp < 0
    end
  end

  def calc_damage_render_queue
    state.damage_render_queue.each { |label| label.a -= 5 }
    state.damage_render_queue.reject! { |l| l.a < 0 }
  end

  def calc_high_score
    state.high_score = boss.damage if boss.damage > state.high_score
  end

  def calc_game_over
    if player.hp <= 0
      state.game_over = true
      state.game_over_countdown ||= 160
    end

    state.game_over_countdown -= 1 if state.game_over_countdown
    state.start_new_game = true    if state.game_over_countdown && state.game_over_countdown < 0
  end

  def render
    render_boss
    render_player
    render_damage_queue
    render_scores
    render_instructions
    render_game_over
    # render_debug
  end

  def render_player
    outputs.labels << { x: player.x + 5,
                        y: player.y + 5,
                        text: "hp: #{player.hp}" }

    if state.game_over
      outputs.labels << { x: player.x + player.tile_size / 2,
                          y: player.y + 85,
                          text: "RIP",
                          size_enum: 2,
                          alignment_enum: 1 }
    elsif !player.damaged_at.elapsed?(120)
      outputs.labels << { x: player.x + player.tile_size / 2,
                          y: player.y + 85,
                          text: "ouch!!",
                          size_enum: 2,
                          alignment_enum: 1 }
    end

    if state.game_over
      outputs.sprites << player_sprite_stand.merge(angle: -90, flip_horizontally: false)
    elsif player.slash_at
      outputs.sprites << player_sprite_slash
    elsif player.is_moving
      outputs.sprites << player_sprite_run
    else
      outputs.sprites << player_sprite_stand
    end
  end

  def render_boss
    outputs.sprites << boss_sprite
  end

  def render_damage_queue
    outputs.labels << state.damage_render_queue
  end

  def render_scores
    outputs.labels << { x: 30, y: 30.from_top, text: "curr score: #{boss.damage}" }
    outputs.labels << { x: 30, y: 50.from_top, text: "high score: #{state.high_score}" }
  end

  def render_instructions
    outputs.labels << { x: 30, y: 70, text: "Controls:" }
    outputs.labels << { x: 30, y: 50, text: "Keyboard:   WASD/Arrow keys to move. J to attack." }
    outputs.labels << { x: 30, y: 30, text: "Controller: D-Pad to move. A/B button to attack." }
  end

  def render_game_over
    return unless state.game_over
    outputs.labels << { x: 640, y: 360, text: "GAME OVER!!!", alignment_enum: 1, size_enum: 3 }
  end

  def render_debug
    outputs.borders << player_sprite_stand
    outputs.borders << player_hurt_box
    outputs.borders << player_hit_box
    outputs.borders << boss_hurt_box
    outputs.borders << boss_hit_box
  end

  def player
    state.player
  end

  def player_x_inside_stage? player_x
    return false if player_x < 0
    return false if (player_x + player.tile_size) > 1280
    return true
  end

  def player_y_inside_stage? player_y
    return false if player_y < 0
    return false if (player_y + player.tile_size) > 720
    return true
  end

  def player_attacking?
    return false if !player.slash_at
    return false if player.slash_at.elapsed?(player.slash_frames)
    return true
  end

  def player_slash_can_damage?
    return false if !player_attacking?
    return false if (player.slash_at + player.slash_frames.idiv(2)) != Kernel.tick_count
    return true
  end

  def player_hit_box
    sword_w = 50
    sword_h = 20
    if player.dir_x > 0
      {
        x: player.x + player.tile_size / 2 + sword_w / 2,
        y: player.y + player.tile_size / 2 - sword_h / 2,
        w: sword_w,
        h: sword_h
      }
    else
      {
        x: player.x + player.tile_size / 2 - sword_w / 2 - sword_w,
        y: player.y + player.tile_size / 2 - sword_h / 2,
        w: sword_w,
        h: sword_h
      }
    end
  end

  def player_hurt_box
    {
      x: player.x + 25,
      y: player.y + 25,
      w: 10,
      h: 10
    }
  end

  def player_sprite_run
    tile_index = 0.frame_index count:    6,
                               hold_for: 3,
                               repeat:   true

    tile_index = 0 if !player.is_moving

    {
      x:                 player.x,
      y:                 player.y,
      w:                 player.tile_size,
      h:                 player.tile_size,
      path:              'sprites/boss-battle/player-run-tile-sheet.png',
      tile_x:            0 + (tile_index * player.tile_size),
      tile_y:            0,
      tile_w:            player.tile_size,
      tile_h:            player.tile_size,
      flip_horizontally: player.dir_x > 0,
    }
  end

  def player_sprite_stand
    {
      x:                 player.x,
      y:                 player.y,
      w:                 player.tile_size,
      h:                 player.tile_size,
      path:              'sprites/boss-battle/player-stand.png',
      flip_horizontally: player.dir_x > 0,
    }
  end

  def player_sprite_slash
    tile_index   = player.slash_at.frame_index count: 5,
                                               hold_for: player.slash_frames.idiv(5),
                                               repeat: false

    tile_index ||= 0
    tile_offset = 41.25

    if player.dir_x > 0
      {
        x:                 player.x - tile_offset,
        y:                 player.y - tile_offset,
        w:                 165,
        h:                 165,
        path:              'sprites/boss-battle/player-slash-tile-sheet.png',
        tile_x:            0 + (tile_index * 128),
        tile_y:            0,
        tile_w:            128,
        tile_h:            128,
        flip_horizontally: true
      }
    else
      {
        x:                 player.x - tile_offset - tile_offset / 2,
        y:                 player.y - tile_offset,
        w:                 165,
        h:                 165,
        path:              'sprites/boss-battle/player-slash-tile-sheet.png',
        tile_x:            0 + (tile_index * 128),
        tile_y:            0,
        tile_w:            128,
        tile_h:            128,
        flip_horizontally: false
      }
    end
  end

  def boss
    state.boss
  end

  def boss_hurt_box
    {
      x: boss.x,
      y: boss.y,
      w: boss.w,
      h: boss.h
    }
  end

  def boss_hit_box
    {
      x: boss.x,
      y: boss.y,
      w: boss.w,
      h: boss.h
    }
  end

  def boss_sprite
    case boss_attack_state
    when :sleeping
      { x: boss.x,
        y: boss.y,
        w: boss.w,
        h: boss.h,
        path: 'sprites/boss-battle/boss-sleeping.png' }
    when :aware
      { x: boss.x,
        y: boss.y,
        w: boss.w,
        h: boss.h,
        path: 'sprites/boss-battle/boss-aware.png' }
    when :annoyed
      { x: boss.x,
        y: boss.y,
        w: boss.w,
        h: boss.h,
        path: 'sprites/boss-battle/boss-annoyed.png' }
    when :will_attack
      shake_x  =  2 * rand
      shake_x *= -1 if rand < 0.5

      shake_y  =  2 * rand
      shake_y *= -1 if rand < 0.5

      { x: boss.x + shake_x,
        y: boss.y + shake_x,
        w: boss.w,
        h: boss.h,
        path: 'sprites/boss-battle/boss-will-attack.png' }
    when :attacking
      flip_horizontally = false
      flip_horizontally = true if boss.target_x > boss.x

      { x: boss.x,
        y: boss.y,
        w: boss.w,
        h: boss.h,
        flip_horizontally: flip_horizontally,
        path: 'sprites/boss-battle/boss-attacking.png' }
    else
      { x: boss.x, y: boss.y, w: boss.w, h: boss.h, r: 255, g: 0, b: 0 }
    end
  end

  def boss_attack_state
    if boss.target_x.round != boss.x.round || boss.target_y.round != boss.y.round
      :attacking
    elsif boss.attack_cooldown < 30
      :will_attack
    elsif boss.attack_cooldown < 120
      :annoyed
    elsif boss.attack_cooldown < 180
      :aware
    else
      :sleeping
    end
  end

  def queue_damage x, y
    rand_x_offset = rand * 20
    rand_y_offset = rand * 20
    rand_x_offset *= -1 if rand < 0.5
    rand_y_offset *= -1 if rand < 0.5
    state.damage_render_queue << { x: x + rand_x_offset, y: y + rand_y_offset, a: 255, text: "wack!" }
  end
end

$game = Game.new

def tick args
  $game.args = args
  $game.tick
end

Genre Crafting link

Alchemy Game Starting Point - main.rb link

# ./samples/99_genre_crafting/alchemy_game_starting_point/app/main.rb
# A collection of function related to elements of natrue
class Element
  # returns the tile size in pixels { w:, h: }
  # Layout::rect is a virtual grid that is 24 columns by 12 rows
  def self.tile_size
    Layout::rect(w: 1, h: 1)
           .slice(:w, :h)
  end

  # given a point/position in pixels, returns a rect with
  # { x:, y:, w:, h:, center: { x:, y: } }
  def self.tile_rect x:, y:, anchor_x: 0, anchor_y: 0, **ignore
    w, h = tile_size.values_at(:w, :h)
    Geometry.rect_props x: x - w * anchor_x,
                        y: y - h * anchor_y,
                        w: w,
                        h: h
  end

  # given a element, and it's position, this fucntion
  # returns render primitives that represent the element
  # visually
  def self.prefab_icon element, x:, y:, anchor_x: 0, anchor_y: 0, **ignore
    # if the element is decorated with an added_at property,
    # it means that we want to apply a fade in effect to the
    # prefab
    a = if element.added_at && element.added_at.elapsed_time < 60
          # fade in slow to fast over 1 second
          perc = Easing.ease element.added_at, Kernel.tick_count, 60, :smooth_start_quint
          255 * perc
        else
          255
        end

    # given the elements position, create a tile rect with the sprite and alpha
    tile_rect(x: x, y: y).merge(path: "sprites/square/#{element.name}.png", a: a)
  end

  # this represents the element prefab it its entirety
  # the sprite, a background rect and a text label above the
  # background rect
  def self.prefab element, position, shift_x: 0, shift_y: 0
    rect = tile_rect x: position.x + shift_x,
                     y: position.y + shift_y

    [
      # icon
      prefab_icon(element, x: position.x, y: position.y),
      # background rect
      rect.merge(path: :solid, h: 16, r: 0, g: 0, b: 0, a: 200),
      # text label
      {
        x: rect.center.x,
        y: rect.y,
        text: "#{element.name}",
        anchor_x: 0.5,
        anchor_y: 0,
        size_px: 16,
        r: 255,
        g: 255,
        b: 255
      },

      # white border
      rect.merge(primitive_marker: :border, r: 255, g: 255, b: 255)
    ]
  end

  # given a collection of elements,
  # this function returns a collection of grouped elements
  # (elements that are intersecting each other, or connected
  # to each other, because of a mutual neighbor element)
  def self.create_groupings elements
    grouped_elements = []

    rects_with_source = elements.map do |r|
      r.rect.merge(source: r)
    end

    rects_with_source.each do |r|
      grouped = grouped_elements.find do |g|
        g.any? { |i| i.intersect_rect? r }
      end

      if !grouped
        grouped_elements << [r]
      else
        grouped << r
      end
    end

    grouped_elements.map do |e|
      e.map { |r| r.source }
    end.uniq
  end
end

class Game
  attr_gtk

  def tick
    defaults
    calc
    render
  end

  def defaults
    # elements of nature and what they require to be created
    state.elements ||= [
      { name: :violet,  requires: [:red, :blue, :black] },
      { name: :indigo,  requires: [:red, :blue, :white] },
      { name: :gray,    requires: [:white, :black] },
      { name: :green,   requires: [:blue, :yellow] },
      { name: :orange,  requires: [:red, :yellow] },
    ]

    # elements that have been discovered seeded with the basic elements
    state.discovered_elements ||= [
      { name: :white },
      { name: :black },
      { name: :red },
      { name: :yellow },
      { name: :blue },
    ]

    # the canvas area where elements are placed/mixed
    state.canvas ||= {
      rect: Layout::rect(row: 0, col: 0, w: 20, h: 12),
      elements: []
    }

    # fx queue for faiding out sprites
    state.fade_out_queue ||= []

    # fx queue for mouse particles
    state.mouse_particles_queue ||= []

    # invalid mixtures queue (used to signal invalid mixtures)
    state.invalid_mixtures_queue ||= []
  end

  # adds a clone of an element to the canvas area
  # used by mouse movement and click events
  # and element discovery
  def add_element_to_canvas! element, position, fade_in: false
    return if !element
    new_entry = element.copy
    new_entry.added_at = Kernel.tick_count if fade_in
    new_entry.position = { x: position.x, y: position.y }
    state.canvas.elements << new_entry
    new_entry
  end

  def input_mouse
    # if the mouse is clicked...
    if inputs.mouse.down
      # check to see if any of the elements in the toolbar
      # were clicked, if so, set the selected element to the
      # clicked element
      toolbar_element = state.discovered_elements
                             .find do |r|
                               inputs.mouse.intersect_rect? r.rect
                             end

      if toolbar_element
        state.selected_element = toolbar_element
      end

      # if no toolbar element was clicked, then check to see
      # if an element on the canvas was clicked
      if !state.selected_element
        state.selected_element = state.canvas.elements.reverse.find do |r|
          inputs.mouse.intersect_rect? r.rect
        end

        # if an element was clicked, remove it from the canvas
        if state.selected_element
          state.canvas.elements.reject! { |r| r == state.selected_element }
        end
      end

      if state.selected_element
        state.selected_element = state.selected_element.copy
      end
    elsif inputs.mouse.held && inputs.mouse.moved
      # emit pretty particles when the mouse is held and moved
      if Kernel.tick_count.zmod? 2
        state.mouse_particles_queue << {
          x: inputs.mouse.x + 10.randomize(:ratio, :sign),
          y: inputs.mouse.y + 10.randomize(:ratio, :sign),
          w: 10, h: 10, path: "sprites/star.png"
        }
      end
    elsif inputs.mouse.up
      if state.selected_element
        # if mouse is released,
        # cr
        if inputs.mouse.intersect_rect?(state.canvas.rect)
          rect = Element.tile_rect(x: inputs.mouse.up.x,
                                   y: inputs.mouse.up.y,
                                   anchor_x: 0.5,
                                   anchor_y: 0.5)


          # add the element to the canvas area and create particles
          # around the element drop
          created_element = add_element_to_canvas! state.selected_element, rect

          # get all intersecting elements with the element that was just being dragged
          intersecting_elements = state.canvas.elements.find_all do |element|
            element != created_element && Geometry::intersect_rect?(element.rect, created_element.rect)
          end

          # shake elements if the element doesn't have any potential interactions
          notify_invalid_mixture! created_element, intersecting_elements

          state.mouse_particles_queue.concat(30.map do |i|
                                               { x: rect.center.x + 10.randomize(:ratio, :sign),
                                                 y: rect.center.y + 10.randomize(:ratio, :sign),
                                                 start_at: Kernel.tick_count + i + rand(2),
                                                 w: 10, h: 10, path: "sprites/star.png" }
                                             end)

        else
          # if the mouse was released outside of the canvas area
          # then delete the element/remove it from the canvas
          w, h = Element.tile_size.values_at(:w, :h)

          # add the element to the fade out queue
          state.fade_out_queue << Element.prefab_icon(state.selected_element,
                                                      x: inputs.mouse.up.x - w / 2,
                                                      y: inputs.mouse.up.y - h / 2,
                                                      anchor_x: 0.5,
                                                      anchor_y: 0.5)
        end
      end

      state.selected_element = nil
    end
  end

  def notify_invalid_mixture! source, intersecting_elements
    return if intersecting_elements.length == 0

    # look through all the intersecting elements
    # see if any of their requirements match the source element
    # or the intersecting element
    possible = intersecting_elements.any? do |r|
      state.elements.any? do |sr|
        sr.requires.include?(source.name) &&
        sr.requires.include?(r.name)
      end
    end

    # check to see if the source element and the intersecting element
    # are of the same type
    duplicate_ids = intersecting_elements.any? { |r| r.name == source.name }

    # play an error sound if the requirements for interactions don't match,
    # or if duplicate elements are touching
    if !possible || duplicate_ids
      state.invalid_mixtures_queue << { ref_id: source.object_id, at: Kernel.tick_count }
      intersecting_elements.each do |r|
        state.invalid_mixtures_queue << { ref_id: r.object_id, at: Kernel.tick_count }
      end
    end
  end

  def calc
    calc_collision_bodies
    input_mouse
    calc_discovered_elements
    calc_queues
    calc_collision_bodies
  end

  def calc_queues
    # process the fade out queue
    state.fade_out_queue.each do |fx|
      fx.dx ||= 0.1
      fx.dy ||= 0.1
      fx.a ||= 255
      fx.a -= 5
      fx.x += fx.dx
      fx.y += fx.dy
      fx.w -= fx.dx * 2 if fx.w > 0
      fx.h -= fx.dy * 2 if fx.h > 0
      fx.dx *= 1.1
      fx.dy *= 1.1
    end

    state.fade_out_queue.reject! { |fx| fx.a <= 0 }

    # process the mouse particles queue
    state.mouse_particles_queue.each do |mp|
      mp.start_at ||= Kernel.tick_count
      mp.a ||= 255
      if mp.start_at < Kernel.tick_count
        mp.dx ||= 1.randomize(:ratio, :sign)
        mp.dy ||= 1.randomize(:ratio, :sign)
        mp.x += mp.dx
        mp.y += mp.dy
        mp.a -= 5
        mp.dx *= 1.05
        mp.dy *= 1.05
      end
    end

    state.mouse_particles_queue.reject! { |mp| mp.a <= 0 }

    state.invalid_mixtures_queue.reject! do |fx|
      fx.at.elapsed_time > 15
    end
  end

  def calc_discovered_elements
    groups = Element.create_groupings state.canvas.elements

    while groups.length > 0
      # pop a group of elements from the groups array
      group = groups.pop

      # for all the elements, get their names, this
      # represets the collection of elements that are
      # needed for other elements to be created (based on their requirements)
      keys = group.map { |g| g.name }
      completed_element = nil

      # for all elements, check their requires, and see if
      # the group of elements that are touching match
      state.elements.each do |r|
        if r.requires.uniq - keys == []
          completed_element = r
          break
        end
      end

      # if an element can be created, then remove the elements
      # that were used to create the element
      if completed_element
        to_remove = []
        completed_element.requires.each do |r|
          group.each do |g|
            if r == g.name
              to_remove << g
              break
            end
          end
        end

        # compute the general center of the cluster of elements
        min_x = to_remove.map { |i| i.position.x }.min
        min_y = to_remove.map { |i| i.position.y }.min
        max_x = to_remove.map { |i| i.position.x }.max
        max_y = to_remove.map { |i| i.position.y }.max
        avg_x = (min_x + max_x) / 2
        avg_y = (min_y + max_y) / 2

        # remove each used element from the canvas
        # fade them out, and add the new element to the canvas
        to_remove.each do |r|
          state.canvas.elements.reject! { |i| i == r }
          state.fade_out_queue << Element.prefab_icon(r, r.position)

          add_element_to_canvas!(completed_element,
                                 Element.tile_rect(x: avg_x, y: avg_y),
                                 fade_in: true)
        end

        # if the newly created element is not in the list of discovered elements
        # then add it to the list of discovered elements
        if state.discovered_elements.none? { |i| i.name == completed_element.name }
          state.discovered_elements << { name: completed_element.name, added_at: Kernel.tick_count }
        end
      end
    end
  end

  def calc_collision_bodies
    state.discovered_elements.each_with_index do |e, i|
      r = Layout::rect(row: i, col: 20, w: 1, h: 1)
      e.merge! rect: Layout::rect(row: i, col: 20, w: 1, h: 1),
               position: r.slice(:x, :y)
    end

    state.canvas.elements.each do |e|
      r = Element.tile_rect(e.position)
      e.merge! rect: r,
               position: r.slice(:x, :y)
    end

    if state.selected_element
      r = Element.tile_rect(x: inputs.mouse.position.x, y: inputs.mouse.position.y, anchor_x: 0.5, anchor_y: 0.5)
      state.selected_element.merge!(rect: r, position: r.slice(:x, :y))
    end
  end

  def render
    render_bg
    render_toolbar
    render_canvas_elements
    render_selected_element
    render_queues
  end

  def render_queues
    outputs.primitives << state.fade_out_queue
    outputs.primitives << state.mouse_particles_queue.reject { |mp| mp.start_at > Kernel.tick_count }
  end

  def render_selected_element
    # if an element is selected, render it at the mouse position
    if state.selected_element
      w, h = Layout::rect(w: 1, h: 1).values_at(:w, :h)
      outputs.primitives << Element.prefab(state.selected_element,
                                           x: inputs.mouse.x - w / 2,
                                           y: inputs.mouse.y - h / 2)
    end
  end

  def render_bg
    # black letterbox
    outputs.background_color = [0, 0, 0]

    # canvas area with lighter purple
    outputs.primitives << Layout::rect(row: 0, col:  0, w: 20, h: 12).merge(path: :solid, r: 59, g: 58, b: 97)

    # toolbar area with darker purple
    outputs.primitives << Layout::rect(row: 0, col: 20, w: 4, h: 12).merge(path: :solid, r: 59, g: 58, b: 80)

    # border around the canvas area
    outputs.primitives << state.canvas.rect.merge(primitive_marker: :border, r: 255, g: 255, b: 255)
  end

  def render_toolbar
    unique_elements = (state.elements.map { |r| r.name } +
                       state.discovered_elements.map { |r| r.name }).uniq
    outputs.primitives << unique_elements.length.map.with_index do |r, i|
      if i <= state.discovered_elements.length - 1
        nil
      else
        # for all undiscovered elements, create a placeholder question mark box
        Layout::rect(row: i, col: 20)
               .yield_self do |r|
                 [
                   r.merge(primitive_marker: :border, r: 255, g: 255, b: 255),
                   r.center.merge(text: "?", anchor_x: 0.5, anchor_y: 0.5, r: 255, g: 255, b: 255)
                 ]
               end
      end
    end

    # create a prefab for each discovered element
    outputs.primitives << state.discovered_elements.map.with_index do |r, i|
      hover = if inputs.mouse.intersect_rect? r.rect
                r.rect.merge(path: :solid, r: 0, g: 80, b: 80, a: 100)
              end

      [Element.prefab(r, r.position), hover]
    end
  end

  def render_canvas_elements
    if inputs.mouse.held && state.selected_element
      grouped_elements = Element.create_groupings(state.canvas.elements)

      # get all elements that are connected to the selected element
      # (ie intersecting with the mouse)
      connected_to_mouse = grouped_elements.find_all do |g|
        g.find { |e| Geometry::intersect_rect? state.selected_element.rect, e.rect }
      end.flatten

      outputs.primitives << state.canvas.elements.map do |element|
        is_part_of_invalid_mixture = state.invalid_mixtures_queue.any? { |i| i.ref_id == element.object_id }

        shift_x, shift_y = if is_part_of_invalid_mixture
                             [5.randomize(:ratio, :sign), 5.randomize(:ratio, :sign)]
                           else
                             [0, 0]
                           end

        pre = Element.prefab element, element.position, shift_x: shift_x, shift_y: shift_y
        # if the element that is about to be rendered is connected to the selected element
        # then render it with a hover effect
        hover = if state.selected_element && connected_to_mouse.any? { |i| i == element }
                  element.rect.merge(path: :solid, r: 0, g: 80, b: 80, a: 100)
                end
        [pre, hover]
      end
    else
      # hover effect for mouse intersecting topmost element
      mouse_intersecting_element = if !inputs.mouse.held
                                     state.canvas.elements.reverse.find do |element|
                                       Geometry::intersect_rect? inputs.mouse, element.rect
                                     end
                                   end

      outputs.primitives << state.canvas.elements.map do |element|
        is_part_of_invalid_mixture = state.invalid_mixtures_queue.any? { |i| i.ref_id == element.object_id }

        shift_x, shift_y = if is_part_of_invalid_mixture
                             [5.randomize(:ratio, :sign), 5.randomize(:ratio, :sign)]
                           else
                             [0, 0]
                           end

        pre = Element.prefab element, element.position, shift_x: shift_x, shift_y: shift_y
        hover = if mouse_intersecting_element == element
                  element.rect.merge(path: :solid, r: 0, g: 80, b: 80, a: 100)
                end
        [pre, hover]
      end
    end
  end
end

$game = Game.new
def tick args
  $game.args = args
  $game.tick
end

Craft Game Starting Point - main.rb link

# ./samples/99_genre_crafting/craft_game_starting_point/app/main.rb
# ==================================================
# A NOTE TO JAM CRAFT PARTICIPANTS:
# The comments and code in here are just as small piece of DragonRuby's capabilities.
# Be sure to check out the rest of the sample apps. Start with README.txt and go from there!
# ==================================================

# def tick args is the entry point into your game. This function is called at
# a fixed update time of 60hz (60 fps).
def tick args
  # The defaults function intitializes the game.
  defaults args

  # After the game is initialized, render it.
  render args

  # After rendering the player should be able to respond to input.
  input args

  # After responding to input, the game performs any additional calculations.
  calc args
end

def defaults args
  # hide the mouse cursor for this game, we are going to render our own cursor
  if Kernel.tick_count == 0
    args.gtk.hide_cursor
  end

  args.state.click_ripples ||= []

  # everything is on a 1280x720 virtual canvas, so you can
  # hardcode locations

  # define the borders for where the inventory is located
  # args.state is a data structure that accepts any arbitrary parameters
  # so you can create an object graph without having to create any classes.

  # Bottom left is 0, 0. Top right is 1280, 720.
  # The inventory area is at the top of the screen
  # the number 80 is the size of all the sprites, so that is what is being
  # used to decide the with and height
  args.state.sprite_size = 80

  args.state.inventory_border.w  = args.state.sprite_size * 10
  args.state.inventory_border.h  = args.state.sprite_size * 3
  args.state.inventory_border.x  = 10
  args.state.inventory_border.y  = 710 - args.state.inventory_border.h

  # define the borders for where the crafting area is located
  # the crafting area is below the inventory area
  # the number 80 is the size of all the sprites, so that is what is being
  # used to decide the with and height
  args.state.craft_border.x =  10
  args.state.craft_border.y = 220
  args.state.craft_border.w = args.state.sprite_size * 3
  args.state.craft_border.h = args.state.sprite_size * 3

  # define the area where results are located
  # the crafting result is to the right of the craft area
  args.state.result_border.x =  10 + args.state.sprite_size * 3 + args.state.sprite_size
  args.state.result_border.y = 220 + args.state.sprite_size
  args.state.result_border.w = args.state.sprite_size
  args.state.result_border.h = args.state.sprite_size

  # initialize items for the first time if they are nil
  # you start with 15 wood, 1 chest, and 5 plank
  # Ruby has built in syntax for dictionaries (they look a lot like json objects).
  # Ruby also has a special type called a Symbol denoted with a : followed by a word.
  # Symbols are nice because they remove the need for magic strings.
  if !args.state.items
    args.state.items = [
      {
        id: :wood, # :wood is a Symbol, this is better than using "wood" for the id
        quantity: 15,
        path: 'sprites/wood.png',
        location: :inventory,
        ordinal_x: 0, ordinal_y: 0
      },
      {
        id: :chest,
        quantity: 1,
        path: 'sprites/chest.png',
        location: :inventory,
        ordinal_x: 1, ordinal_y: 0
      },
      {
        id: :plank,
        quantity: 5,
        path: 'sprites/plank.png',
        location: :inventory,
        ordinal_x: 2, ordinal_y: 0
      },
    ]

    # after initializing the oridinal positions, derive the pixel
    # locations assuming that the width and height are 80
    args.state.items.each { |item| set_inventory_position args, item }
  end

  # define all the oridinal positions of the inventory slots
  if !args.state.inventory_area
    args.state.inventory_area = [
      { ordinal_x: 0,  ordinal_y: 0 },
      { ordinal_x: 1,  ordinal_y: 0 },
      { ordinal_x: 2,  ordinal_y: 0 },
      { ordinal_x: 3,  ordinal_y: 0 },
      { ordinal_x: 4,  ordinal_y: 0 },
      { ordinal_x: 5,  ordinal_y: 0 },
      { ordinal_x: 6,  ordinal_y: 0 },
      { ordinal_x: 7,  ordinal_y: 0 },
      { ordinal_x: 8,  ordinal_y: 0 },
      { ordinal_x: 9,  ordinal_y: 0 },
      { ordinal_x: 0,  ordinal_y: 1 },
      { ordinal_x: 1,  ordinal_y: 1 },
      { ordinal_x: 2,  ordinal_y: 1 },
      { ordinal_x: 3,  ordinal_y: 1 },
      { ordinal_x: 4,  ordinal_y: 1 },
      { ordinal_x: 5,  ordinal_y: 1 },
      { ordinal_x: 6,  ordinal_y: 1 },
      { ordinal_x: 7,  ordinal_y: 1 },
      { ordinal_x: 8,  ordinal_y: 1 },
      { ordinal_x: 9,  ordinal_y: 1 },
      { ordinal_x: 0,  ordinal_y: 2 },
      { ordinal_x: 1,  ordinal_y: 2 },
      { ordinal_x: 2,  ordinal_y: 2 },
      { ordinal_x: 3,  ordinal_y: 2 },
      { ordinal_x: 4,  ordinal_y: 2 },
      { ordinal_x: 5,  ordinal_y: 2 },
      { ordinal_x: 6,  ordinal_y: 2 },
      { ordinal_x: 7,  ordinal_y: 2 },
      { ordinal_x: 8,  ordinal_y: 2 },
      { ordinal_x: 9,  ordinal_y: 2 },
    ]

    # after initializing the oridinal positions, derive the pixel
    # locations assuming that the width and height are 80
    args.state.inventory_area.each { |i| set_inventory_position args, i }

    # if you want to see the result you can use the Ruby function called "puts".
    # Uncomment this line to see the value.
    # puts args.state.inventory_area

    # You can see all things written via puts in DragonRuby's Console, or under logs/log.txt.
    # To bring up DragonRuby's Console, press the ~ key within the game.
  end

  # define all the oridinal positions of the craft slots
  if !args.state.craft_area
    args.state.craft_area = [
      { ordinal_x: 0, ordinal_y: 0 },
      { ordinal_x: 0, ordinal_y: 1 },
      { ordinal_x: 0, ordinal_y: 2 },
      { ordinal_x: 1, ordinal_y: 0 },
      { ordinal_x: 1, ordinal_y: 1 },
      { ordinal_x: 1, ordinal_y: 2 },
      { ordinal_x: 2, ordinal_y: 0 },
      { ordinal_x: 2, ordinal_y: 1 },
      { ordinal_x: 2, ordinal_y: 2 },
    ]

    # after initializing the oridinal positions, derive the pixel
    # locations assuming that the width and height are 80
    args.state.craft_area.each { |c| set_craft_position args, c }
  end
end


def render args
  # for the results area, create a sprite that show its boundaries
  args.outputs.primitives << { x: args.state.result_border.x,
                               y: args.state.result_border.y,
                               w: args.state.result_border.w,
                               h: args.state.result_border.h,
                               path: 'sprites/border-black.png' }

  # for each inventory spot, create a sprite
  # args.outputs.primitives is how DragonRuby performs a render.
  # Adding a single hash or multiple hashes to this array will tell
  # DragonRuby to render those primitives on that frame.

  # The .map function on Array is used instead of any kind of looping.
  # .map returns a new object for every object within an Array.
  args.outputs.primitives << args.state.inventory_area.map do |a|
    { x: a.x, y: a.y, w: a.w, h: a.h, path: 'sprites/border-black.png' }
  end

  # for each craft spot, create a sprite
  args.outputs.primitives << args.state.craft_area.map do |a|
    { x: a.x, y: a.y, w: a.w, h: a.h, path: 'sprites/border-black.png' }
  end

  # after the borders have been rendered, render the
  # items within those slots (and allow for highlighting)
  # if an item isn't currently being held
  allow_inventory_highlighting = !args.state.held_item

  # go through each item and render them
  # use Array's find_all method to remove any items that are currently being held
  args.state.items.find_all { |item| item[:location] != :held }.map do |item|
    # if an item is currently being held, don't render it in it's spot within the
    # inventory or craft area (this is handled via the find_all method).

    # the item_prefab returns a hash containing all the visual components of an item.
    # the main sprite, the black background, the quantity text, and a hover indication
    # if the mouse is currently hovering over the item.
    args.outputs.primitives << item_prefab(args, item, allow_inventory_highlighting, args.inputs.mouse)
  end

  # The last thing we want to render is the item currently being held.
  args.outputs.primitives << item_prefab(args, args.state.held_item, allow_inventory_highlighting, args.inputs.mouse)

  args.outputs.primitives << args.state.click_ripples

  # render a mouse cursor since we have the OS cursor hidden
  args.outputs.primitives << { x: args.inputs.mouse.x - 5, y: args.inputs.mouse.y - 5, w: 10, h: 10, path: 'sprites/circle-gray.png', a: 128 }
end

# Alrighty! This is where all the fun happens
def input args
  # if the mouse is clicked and not item is currently being held
  # args.state.held_item is nil when the game starts.
  # If the player clicks, the property args.inputs.mouse.click will
  # be a non nil value, we don't want to process any of the code here
  # if the mouse hasn't been clicked
  return if !args.inputs.mouse.click

  # if a click occurred, add a ripple to the ripple queue
  args.state.click_ripples << { x: args.inputs.mouse.x - 5, y: args.inputs.mouse.y - 5, w: 10, h: 10, path: 'sprites/circle-gray.png', a: 128 }

  # if the mouse has been clicked, and no item is currently held...
  if !args.state.held_item
    # see if any of the items intersect the pointer using the inside_rect? method
    # the find method will either return the first object that returns true
    # for the match clause, or it'll return nil if nothing matches the match clause
    found = args.state.items.find do |item|
      # for each item in args.state.items, run the following boolean check
      args.inputs.mouse.click.point.inside_rect?(item)
    end

    # if an item intersects the mouse pointer, then set the item's location to :held and
    # set args.state.held_item to the item for later reference
    if found
      args.state.held_item = found
      found[:location] = :held
    end

  # if the mouse is clicked and an item is currently beign held....
  elsif args.state.held_item
    # determine if a slot within the craft area was clicked
    craft_area = args.state.craft_area.find { |a| args.inputs.mouse.click.point.inside_rect? a }

    # also determine if a slot within the inventory area was clicked
    inventory_area = args.state.inventory_area.find { |a| args.inputs.mouse.click.point.inside_rect? a }

    # if the click was within a craft area
    if craft_area
      # check to see if an item is already there and ignore the click if an item is found
      # item_at_craft_slot is a helper method that returns an item or nil for a given oridinal
      # position
      item_already_there = item_at_craft_slot args, craft_area[:ordinal_x], craft_area[:ordinal_y]

      # if an item *doesn't* exist in the craft area
      if !item_already_there
        # if the quantity they are currently holding is greater than 1
        if args.state.held_item[:quantity] > 1
          # remove one item (creating a seperate item of the same type), and place it
          # at the oridinal position and location of the craft area
          # the .merge method on Hash creates a new Hash, but updates any values
          # passed as arguments to merge
          new_item = args.state.held_item.merge(quantity: 1,
                                                location: :craft,
                                                ordinal_x: craft_area[:ordinal_x],
                                                ordinal_y: craft_area[:ordinal_y])

          # after the item is crated, place it into the args.state.items collection
          args.state.items << new_item

          # then subtract one from the held item
          args.state.held_item[:quantity] -= 1

        # if the craft area is available and there is only one item being held
        elsif args.state.held_item[:quantity] == 1
          # instead of creating any new items just set the location of the held item
          # to the oridinal position of the craft area, and then nil out the
          # held item state so that a new item can be picked up
          args.state.held_item[:location] = :craft
          args.state.held_item[:ordinal_x] = craft_area[:ordinal_x]
          args.state.held_item[:ordinal_y] = craft_area[:ordinal_y]
          args.state.held_item = nil
        end
      end

    # if the selected area is an inventory area (as opposed to within the craft area)
    elsif inventory_area

      # check to see if there is already an item in that inventory slot
      # the item_at_inventory_slot helper method returns an item or nil
      item_already_there = item_at_inventory_slot args, inventory_area[:ordinal_x], inventory_area[:ordinal_y]

      # if there is already an item there, and the item types/id match
      if item_already_there && item_already_there[:id] == args.state.held_item[:id]
        # then merge the item quantities
        held_quantity = args.state.held_item[:quantity]
        item_already_there[:quantity] += held_quantity

        # remove the item being held from the items collection (since it's quantity is now 0)
        args.state.items.reject! { |i| i[:location] == :held }

        # nil out the held_item so a new item can be picked up
        args.state.held_item = nil

      # if there currently isn't an item there, then put the held item in the slot
      elsif !item_already_there
        args.state.held_item[:location] = :inventory
        args.state.held_item[:ordinal_x] = inventory_area[:ordinal_x]
        args.state.held_item[:ordinal_y] = inventory_area[:ordinal_y]

        # nil out the held_item so a new item can be picked up
        args.state.held_item = nil
      end
    end
  end
end

# the calc method is executed after input
def calc args
  # make sure that the real position of the inventory
  # items are updated every frame to ensure that they
  # are placed correctly given their location and oridinal positions
  # instead of using .map, here we use .each (since we are not returning a new item and just updating the items in place)
  args.state.items.each do |item|
    # based on the location of the item, invoke the correct pixel conversion method
    if item[:location] == :inventory
      set_inventory_position args, item
    elsif item[:location] == :craft
      set_craft_position args, item
    elsif item[:location] == :held
      # if the item is held, center the item around the mouse pointer
      args.state.held_item.x = args.inputs.mouse.x - args.state.held_item.w.half
      args.state.held_item.y = args.inputs.mouse.y - args.state.held_item.h.half
    end
  end

  # for each hash/sprite in the click ripples queue,
  # expand its size by 20 percent and decrease its alpha
  # by 10.
  args.state.click_ripples.each do |ripple|
    delta_w = ripple.w * 1.2 - ripple.w
    delta_h = ripple.h * 1.2 - ripple.h
    ripple.x -= delta_w.half
    ripple.y -= delta_h.half
    ripple.w += delta_w
    ripple.h += delta_h
    ripple.a -= 10
  end

  # remove any items from the collection where the alpha value is less than equal to
  # zero using the reject! method (reject with an exclamation point at the end changes the
  # array value in place, while reject without the exclamation point returns a new array).
  args.state.click_ripples.reject! { |ripple| ripple.a <= 0 }
end

# helper function for finding an item at a craft slot
def item_at_craft_slot args, ordinal_x, ordinal_y
  args.state.items.find { |i| i[:location] == :craft && i[:ordinal_x] == ordinal_x && i[:ordinal_y] == ordinal_y }
end

# helper function for finding an item at an inventory slot
def item_at_inventory_slot args, ordinal_x, ordinal_y
  args.state.items.find { |i| i[:location] == :inventory && i[:ordinal_x] == ordinal_x && i[:ordinal_y] == ordinal_y }
end

# helper function that creates a visual representation of an item
def item_prefab args, item, should_highlight, mouse
  return nil unless item

  overlay = nil

  x = item.x
  y = item.y
  w = item.w
  h = item.h

  if should_highlight && mouse.point.inside_rect?(item)
    overlay = { x: x, y: y, w: w, h: h, path: "sprites/square-blue.png", a: 130, }
  end

  [
    # sprites are hashes with a path property, this is the main sprite
    { x: x,      y: y, w: args.state.sprite_size, h: args.state.sprite_size, path: item[:path], },

    # this represents the black area in the bottom right corner of the main sprite so that the
    # quantity is visible
    { x: x + 55, y: y, w: 25, h: 25, path: "sprites/square-black.png", }, # sprites are hashes with a path property

    # labels are hashes with a text property
    { x: x + 56, y: y + 22, text: "#{item[:quantity]}", r: 255, g: 255, b: 255, },

    # this is the mouse overlay, if the overlay isn't applicable, then this value will be nil (nil values will not be rendered)
    overlay
  ]
end

# helper function for deriving the position of an item within inventory
def set_inventory_position args, item
  item.x = args.state.inventory_border.x + item[:ordinal_x] * 80
  item.y = (args.state.inventory_border.y + args.state.inventory_border.h - 80) - item[:ordinal_y] * 80
  item.w = 80
  item.h = 80
end

# helper function for deriving the position of an item within the craft area
def set_craft_position args, item
  item.x = args.state.craft_border.x + item[:ordinal_x] * 80
  item.y = (args.state.craft_border.y + args.state.inventory_border.h - 80) - item[:ordinal_y] * 80
  item.w = 80
  item.h = 80
end

# Any lines outside of a function will be executed when the file is reloaded.
# So every time you save main.rb, the game will be reset.
# Comment out the line below if you don't want this to happen.
$gtk.reset

Farming Game Starting Point - main.rb link

# ./samples/99_genre_crafting/farming_game_starting_point/app/main.rb
def tick args
  args.state.tile_size     = 80
  args.state.player_speed  = 4
  args.state.player      ||= tile(args, 7, 3, 0, 128, 180)
  generate_map args
  #press j to plant a green onion
  if args.inputs.keyboard.j
  #change this part you can change what you want to plant
   args.state.walls << tile(args, ((args.state.player.x+80)/args.state.tile_size), ((args.state.player.y)/args.state.tile_size), 255, 255, 255)
   args.state.plants << tile(args, ((args.state.player.x+80)/args.state.tile_size), ((args.state.player.y+80)/args.state.tile_size), 0, 160, 0)
  end
  # Adds walls, background, and player to args.outputs.solids so they appear on screen
  args.outputs.solids << [0,0,1280,720, 237,189,101]
  args.outputs.sprites << [0, 0, 1280, 720, 'sprites/background.png']
  args.outputs.solids << args.state.walls
  args.outputs.solids << args.state.player
  args.outputs.solids << args.state.plants
  args.outputs.labels << [320, 640, "press J to plant", 3, 1, 255, 0, 0, 200]

  move_player args, -1,  0 if args.inputs.keyboard.left # x position decreases by 1 if left key is pressed
  move_player args,  1,  0 if args.inputs.keyboard.right # x position increases by 1 if right key is pressed
  move_player args,  0,  1 if args.inputs.keyboard.up # y position increases by 1 if up is pressed
  move_player args,  0, -1 if args.inputs.keyboard.down # y position decreases by 1 if down is pressed
end

# Sets position, size, and color of the tile
def tile args, x, y, *color
  [x * args.state.tile_size, # sets definition for array using method parameters
   y * args.state.tile_size, # multiplying by tile_size sets x and y to correct position using pixel values
   args.state.tile_size,
   args.state.tile_size,
   *color]
end

# Creates map by adding tiles to the wall, as well as a goal (that the player needs to reach)
def generate_map args
  return if args.state.area

  # Creates the area of the map. There are 9 rows running horizontally across the screen
  # and 16 columns running vertically on the screen. Any spot with a "1" is not
  # open for the player to move into (and is green), and any spot with a "0" is available
  # for the player to move in.
  args.state.area = [
    [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,],
    [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,],
    [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,],
    [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,],
    [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,],
    [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,],
    [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,],
    [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,],
    [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ],
  ].reverse # reverses the order of the area collection

  # By reversing the order, the way that the area appears above is how it appears
  # on the screen in the game. If we did not reverse, the map would appear inverted.

  #The wall starts off with no tiles.
  args.state.walls = []
  args.state.plants = []

  # If v is 1, a green tile is added to args.state.walls.
  # If v is 2, a black tile is created as the goal.
  args.state.area.map_2d do |y, x, v|
    if    v == 1
      args.state.walls << tile(args, x, y, 255, 160, 156) # green tile
    end
  end
end

# Allows the player to move their box around the screen
def move_player args, *vector
  box = args.state.player.shift_rect(vector) # box is able to move at an angle

  # If the player's box hits a wall, it is not able to move further in that direction
  return if args.state.walls
                .any_intersect_rect?(box)

  # Player's box is able to move at angles (not just the four general directions) fast
  args.state.player =
    args.state.player
        .shift_rect(vector.x * args.state.player_speed, # if we don't multiply by speed, then
                    vector.y * args.state.player_speed) # the box will move extremely slow
end

Genre Dev Tools link

Add Buttons To Console - main.rb link

# ./samples/99_genre_dev_tools/add_buttons_to_console/app/main.rb
# You can customize the buttons that show up in the Console.
class GTK::Console::Menu
  # STEP 1: Override the custom_buttons function.
  def custom_buttons
    [
      (button id: :yay,
              # row for button
              row: 2,
              # column for button
              col: 18,
              # text
              text: "I AM CUSTOM",
              # when clicked call the custom_button_clicked function
              method: :custom_button_clicked),

      (button id: :yay,
              # row for button
              row: 2,
              # column for button
              col: 16,
              # text
              text: "CUSTOM ALSO",
              # when clicked call the custom_button_also_clicked function
              method: :custom_button_also_clicked)
    ]
  end

  # STEP 2: Define the function that should be called.
  def custom_button_clicked
    log "* INFO: I AM CUSTOM was clicked!"
  end

  def custom_button_also_clicked
    log "* INFO: Custom Button Clicked at #{Kernel.global_tick_count}!"

    all_buttons_as_string = $gtk.console.menu.buttons.map do |b|
      <<-S.strip
** id: #{b[:id]}
:PROPERTIES:
:id:     :#{b[:id]}
:method: :#{b[:method]}
:text:   #{b[:text]}
:END:
S
    end.join("\n")

    log <<-S
* INFO: Here are all the buttons:
#{all_buttons_as_string}
S
  end
end

def tick args
  args.outputs.labels << [args.grid.center.x, args.grid.center.y,
                          "Open the DragonRuby Console to see the custom menu items.",
                          0, 1]
end

Animation Creator Starting Point - main.rb link

# ./samples/99_genre_dev_tools/animation_creator_starting_point/app/main.rb
class OneBitLowrezPaint
  attr_gtk

  def tick
    outputs.background_color = [0, 0, 0]
    defaults
    render_instructions
    render_canvas
    render_buttons_frame_selection
    render_animation_frame_thumbnails
    render_animation
    input_mouse_click
    input_keyboard
    calc_auto_export
    calc_buttons_frame_selection
    calc_animation_frames
    process_queue_create_sprite
    process_queue_reset_sprite
    process_queue_update_rt_animation_frame
  end

  def defaults
    state.animation_frames_per_second = 12
    queues.create_sprite ||= []
    queues.reset_sprite ||= []
    queues.update_rt_animation_frame ||= []

    if !state.animation_frames
      state.animation_frames ||= []
      add_animation_frame_to_end
    end

    state.last_mouse_down ||= 0
    state.last_mouse_up   ||= 0

    state.buttons_frame_selection.left = 10
    state.buttons_frame_selection.top  = grid.top - 10
    state.buttons_frame_selection.size = 20
    state.buttons_frame_selection.items ||= []

    defaults_canvas_sprite

    state.edit_mode ||= :drawing
  end

  def defaults_canvas_sprite
    rt_canvas.size   = 16
    rt_canvas.zoom   = 30
    rt_canvas.width  = rt_canvas.size * rt_canvas.zoom
    rt_canvas.height = rt_canvas.size * rt_canvas.zoom
    rt_canvas.sprite = { x: 0,
                         y: 0,
                         w: rt_canvas.width,
                         h: rt_canvas.height,
                         path: :rt_canvas }.center_inside_rect(x: 0, y: 0, w: 640, h: 720)

    return unless Kernel.tick_count == 1

    outputs[:rt_canvas].width      = rt_canvas.width
    outputs[:rt_canvas].height     = rt_canvas.height
    outputs[:rt_canvas].sprites   << (rt_canvas.size + 1).map_with_index do |x|
      (rt_canvas.size + 1).map_with_index do |y|
        path = 'sprites/square-white.png'
        path = 'sprites/square-blue.png' if x == 7 || x == 8
        { x: x * rt_canvas.zoom,
          y: y * rt_canvas.zoom,
          w: rt_canvas.zoom,
          h: rt_canvas.zoom,
          path: path,
          a: 50 }
      end
    end
  end

  def render_instructions
    instructions = [
      "* Hotkeys:",
      "- d: hold to erase, release to draw.",
      "- a: add frame.",
      "- c: copy frame.",
      "- v: paste frame.",
      "- x: delete frame.",
      "- b: go to previous frame.",
      "- f: go to next frame.",
      "- w: save to ./canvas directory.",
      "- l: load from ./canvas."
    ]

    instructions.each.with_index do |l, i|
      outputs.labels << { x: 840, y: 500 - (i * 20), text: "#{l}",
                          r: 180, g: 180, b: 180, size_enum: 0 }
    end
  end

  def render_canvas
    return if Kernel.tick_count.zero?
    outputs.sprites << rt_canvas.sprite
  end

  def render_buttons_frame_selection
    args.outputs.primitives << state.buttons_frame_selection.items.map_with_index do |b, i|
      label = { x: b.x + state.buttons_frame_selection.size.half,
                y: b.y,
                text: "#{i + 1}", r: 180, g: 180, b: 180,
                size_enum: -4, alignment_enum: 1 }.label!

      selection_border = b.merge(r: 40, g: 40, b: 40).border!

      if i == state.animation_frames_selected_index
        selection_border = b.merge(r: 40, g: 230, b: 200).border!
      end

      [selection_border, label]
    end
  end

  def render_animation_frame_thumbnails
    return if Kernel.tick_count.zero?

    outputs[:current_animation_frame].width   = rt_canvas.size
    outputs[:current_animation_frame].height  = rt_canvas.size
    outputs[:current_animation_frame].solids <<  selected_animation_frame.pixels.map_with_index do |f, i|
      { x: f.x,
        y: f.y,
        w: 1,
        h: 1, r: 255, g: 255, b: 255 }
    end

    outputs.sprites << rt_canvas.sprite.merge(path: :current_animation_frame)

    state.animation_frames.map_with_index do |animation_frame, animation_frame_index|
      outputs.sprites << state.buttons_frame_selection.items[animation_frame_index].inner_rect
                              .merge(path: animation_frame.rt_name)
    end
  end

  def render_animation
    sprite_index = 0.frame_index count: state.animation_frames.length,
                                 hold_for: 60 / state.animation_frames_per_second,
                                 repeat: true

    args.outputs.sprites << { x: 700 - 8,
                              y: 120,
                              w: 16,
                              h: 16,
                              path: (sprite_path sprite_index) }

    args.outputs.sprites << { x: 700 - 16,
                              y: 230,
                              w: 32,
                              h: 32,
                              path: (sprite_path sprite_index) }

    args.outputs.sprites << { x: 700 - 32,
                              y: 360,
                              w: 64,
                              h: 64,
                              path: (sprite_path sprite_index) }

    args.outputs.sprites << { x: 700 - 64,
                              y: 520,
                              w: 128,
                              h: 128,
                              path: (sprite_path sprite_index) }
  end

  def input_mouse_click
    if inputs.mouse.up
      state.last_mouse_up = Kernel.tick_count
    elsif inputs.mouse.moved && user_is_editing?
      edit_current_animation_frame inputs.mouse.point
    end

    return unless inputs.mouse.click

    clicked_frame_button = state.buttons_frame_selection.items.find do |b|
      inputs.mouse.point.inside_rect? b
    end

    if (clicked_frame_button)
      state.animation_frames_selected_index = clicked_frame_button.index
    end

    if (inputs.mouse.point.inside_rect? rt_canvas.sprite)
      state.last_mouse_down = Kernel.tick_count
      edit_current_animation_frame inputs.mouse.point
    end
  end

  def input_keyboard
    # w to save
    if inputs.keyboard.key_down.w
      t = Time.now
      state.save_description = "Time: #{t} (#{t.to_i})"
      gtk.serialize_state 'canvas/state.txt', state
      gtk.serialize_state "tmp/canvas_backups/#{t.to_i}/state.txt", state
      animation_frames.each_with_index do |animation_frame, i|
        queues.update_rt_animation_frame << { index: i,
                                              at: Kernel.tick_count + i,
                                              queue_sprite_creation: true }
        queues.create_sprite << { index: i,
                                  at: Kernel.tick_count + animation_frames.length + i,
                                  path_override: "tmp/canvas_backups/#{t.to_i}/sprite-#{i}.png" }
      end
      gtk.notify! "Canvas saved."
    end

    # l to load
    if inputs.keyboard.key_down.l
      args.state = gtk.deserialize_state 'canvas/state.txt'
      animation_frames.each_with_index do |a, i|
        queues.update_rt_animation_frame << { index: i,
                                              at: Kernel.tick_count + i,
                                              queue_sprite_creation: true }
      end
      gtk.notify! "Canvas loaded."
    end

    # d to go into delete mode, release to paint
    if inputs.keyboard.key_held.d
      state.edit_mode = :erasing
      gtk.notify! "Erasing." if inputs.keyboard.key_held.d == (Kernel.tick_count - 1)
    elsif inputs.keyboard.key_up.d
      state.edit_mode = :drawing
      gtk.notify! "Drawing."
    end

    # a to add a frame to the end
    if inputs.keyboard.key_down.a
      queues.create_sprite << { index: state.animation_frames_selected_index,
                                at: Kernel.tick_count }
      queues.create_sprite << { index: state.animation_frames_selected_index + 1,
                                at: Kernel.tick_count }
      add_animation_frame_to_end
      gtk.notify! "Frame added to end."
    end

    # c or t to copy
    if (inputs.keyboard.key_down.c || inputs.keyboard.key_down.t)
      state.clipboard = [selected_animation_frame.pixels].flatten
      gtk.notify! "Current frame copied."
    end

    # v or q to paste
    if (inputs.keyboard.key_down.v || inputs.keyboard.key_down.q) && state.clipboard
      selected_animation_frame.pixels = [state.clipboard].flatten
      queues.update_rt_animation_frame << { index: state.animation_frames_selected_index,
                                            at: Kernel.tick_count,
                                            queue_sprite_creation: true }
      gtk.notify! "Pasted."
    end

    # f to go forward/next frame
    if (inputs.keyboard.key_down.f)
      if (state.animation_frames_selected_index == (state.animation_frames.length - 1))
        state.animation_frames_selected_index = 0
      else
        state.animation_frames_selected_index += 1
      end
      gtk.notify! "Next frame."
    end

    # b to go back/previous frame
    if (inputs.keyboard.key_down.b)
      if (state.animation_frames_selected_index == 0)
        state.animation_frames_selected_index = state.animation_frames.length - 1
      else
        state.animation_frames_selected_index -= 1
      end
      gtk.notify! "Previous frame."
    end

    # x to delete frame
    if (inputs.keyboard.key_down.x) && animation_frames.length > 1
      state.clipboard = selected_animation_frame.pixels
      state.animation_frames = animation_frames.find_all { |v| v.index != state.animation_frames_selected_index }
      if state.animation_frames_selected_index >= state.animation_frames.length
        state.animation_frames_selected_index = state.animation_frames.length - 1
      end
      gtk.notify! "Frame deleted."
    end
  end

  def calc_auto_export
    return if user_is_editing?
    return if state.last_mouse_up.elapsed_time != 30
    # auto export current animation frame if there is no editing for 30 ticks
    queues.create_sprite << { index: state.animation_frames_selected_index,
                              at: Kernel.tick_count }
  end

  def calc_buttons_frame_selection
    state.buttons_frame_selection.items = animation_frames.length.map_with_index do |i|
      { x: state.buttons_frame_selection.left + i * state.buttons_frame_selection.size,
        y: state.buttons_frame_selection.top - state.buttons_frame_selection.size,
        inner_rect: {
          x: (state.buttons_frame_selection.left + 2) + i * state.buttons_frame_selection.size,
          y: (state.buttons_frame_selection.top - state.buttons_frame_selection.size + 2),
          w: 16,
          h: 16,
        },
        w: state.buttons_frame_selection.size,
        h: state.buttons_frame_selection.size,
        index: i }
    end
  end

  def calc_animation_frames
    animation_frames.each_with_index do |animation_frame, i|
      animation_frame.index = i
      animation_frame.rt_name = "animation_frame_#{i}"
    end
  end

  def process_queue_create_sprite
    sprites_to_create = queues.create_sprite
                              .find_all { |h| h.at.elapsed? }

    queues.create_sprite = queues.create_sprite - sprites_to_create

    sprites_to_create.each do |h|
      export_animation_frame h.index, h.path_override
    end
  end

  def process_queue_reset_sprite
    sprites_to_reset = queues.reset_sprite
                             .find_all { |h| h.at.elapsed? }

    queues.reset_sprite -= sprites_to_reset

    sprites_to_reset.each { |h| gtk.reset_sprite (sprite_path h.index) }
  end

  def process_queue_update_rt_animation_frame
    animation_frames_to_update = queues.update_rt_animation_frame
                                       .find_all { |h| h.at.elapsed? }

    queues.update_rt_animation_frame -= animation_frames_to_update

    animation_frames_to_update.each do |h|
      update_animation_frame_render_target animation_frames[h.index]

      if h.queue_sprite_creation
        queues.create_sprite << { index: h.index,
                                  at: Kernel.tick_count + 1 }
      end
    end
  end

  def update_animation_frame_render_target animation_frame
    return if !animation_frame

    outputs[animation_frame.rt_name].width   = state.rt_canvas.size
    outputs[animation_frame.rt_name].height  = state.rt_canvas.size
    outputs[animation_frame.rt_name].solids << animation_frame.pixels.map do |f|
      { x: f.x,
        y: f.y,
        w: 1,
        h: 1, r: 255, g: 255, b: 255 }
    end
  end

  def animation_frames
    state.animation_frames
  end

  def add_animation_frame_to_end
    animation_frames << {
      index: animation_frames.length,
      pixels: [],
      rt_name: "animation_frame_#{animation_frames.length}"
    }

    state.animation_frames_selected_index = (animation_frames.length - 1)
    queues.update_rt_animation_frame << { index: state.animation_frames_selected_index,
                                          at: Kernel.tick_count,
                                          queue_sprite_creation: true }
  end

  def sprite_path i
    "canvas/sprite-#{i}.png"
  end

  def export_animation_frame i, path_override = nil
    return if !state.animation_frames[i]

    outputs.screenshots << state.buttons_frame_selection
                                .items[i].inner_rect
                                .merge(path: path_override || (sprite_path i))

    outputs.screenshots << state.buttons_frame_selection
                                .items[i].inner_rect
                                .merge(path: "tmp/sprite_backups/#{Time.now.to_i}-sprite-#{i}.png")

    queues.reset_sprite << { index: i, at: Kernel.tick_count }
  end

  def selected_animation_frame
    state.animation_frames[state.animation_frames_selected_index]
  end

  def edit_current_animation_frame point
    draw_area_point = (to_draw_area point)
    if state.edit_mode == :drawing && (!selected_animation_frame.pixels.include? draw_area_point)
      selected_animation_frame.pixels << draw_area_point
      queues.update_rt_animation_frame << { index: state.animation_frames_selected_index,
                                            at: Kernel.tick_count,
                                            queue_sprite_creation: !user_is_editing? }
    elsif state.edit_mode == :erasing && (selected_animation_frame.pixels.include? draw_area_point)
      selected_animation_frame.pixels = selected_animation_frame.pixels.reject { |p| p == draw_area_point }
      queues.update_rt_animation_frame << { index: state.animation_frames_selected_index,
                                            at: Kernel.tick_count,
                                            queue_sprite_creation: !user_is_editing? }
    end
  end

  def user_is_editing?
    state.last_mouse_down > state.last_mouse_up
  end

  def to_draw_area point
    x, y = point.x, point.y
    x -= rt_canvas.sprite.x
    y -= rt_canvas.sprite.y
    { x: x.idiv(rt_canvas.zoom),
      y: y.idiv(rt_canvas.zoom) }
  end

  def rt_canvas
    state.rt_canvas ||= state.new_entity(:rt_canvas)
  end

  def queues
    state.queues ||= state.new_entity(:queues)
  end
end

$game = OneBitLowrezPaint.new

def tick args
  $game.args = args
  $game.tick
end

# $gtk.reset

Frame By Frame - main.rb link

# ./samples/99_genre_dev_tools/frame_by_frame/app/main.rb
def tick args
  # create a tick count variant called clock
  # so I can manually control "tick_count"
  args.state.clock ||= 0

  # calc for frame by frame stepping
  calc_debug args

  # conditional calc of game
  calc_game args

  # always render game
  render_game args

  # increment clock
  if args.state.frame_by_frame
    if args.state.increment_frame > 0
      args.state.clock += 1
    end
  else
    args.state.clock += 1
  end
end

def calc_debug args
  # create an increment_frame counter for frame by frame
  # stepping
  args.state.increment_frame ||= 0
  args.state.increment_frame  -= 1

  # press l to increment by 30 frames or if any key is pressed
  if args.inputs.keyboard.key_down.l || args.inputs.keyboard.key_down.truthy_keys.length > 0
    args.state.increment_frame = 30
  end

  # enable disable frame by frame mode
  if args.inputs.keyboard.key_down.p
    if args.state.frame_by_frame == true
      args.state.frame_by_frame = false
    else
      args.state.frame_by_frame = true
      args.state.increment_frame = 0
    end
  end

  # press k to increment by one frame
  if args.inputs.keyboard.key_down.k
    args.state.increment_frame = 1
  end
end

def render_game args
  args.outputs.sprites << args.state.player
end

def calc_game args
  return if args.state.frame_by_frame && args.state.increment_frame < 0

  args.state.player ||= {
    x: 0,
    y: 360,
    w: 40,
    h: 40,
    anchor_x: 0.5,
    anchor_y: 0.5,
    path: :pixel,
    r: 0, g: 0, b: 255
  }

  args.state.player.x += 10
  args.state.player.y += args.inputs.up_down * 10

  if args.state.player.x > 1280
    args.state.player.x = 0
  end

  if args.state.player.y > 720
    args.state.player.y = 0
  elsif args.state.player.y < 0
    args.state.player.y = 720
  end
end

$gtk.reset

Tile Editor Starting Point - main.rb link

# ./samples/99_genre_dev_tools/tile_editor_starting_point/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - to_s: Returns a string representation of an object.
   For example, if we had
   500.to_s
   the string "500" would be returned.
   Similar to to_i, which returns an integer representation of an object.

 - Ceil: Returns an integer number greater than or equal to the original
   with no decimal.

 Reminders:

 - ARRAY#inside_rect?: Returns true or false depending on if the point is inside a rect.

 - args.outputs.labels: An array. The values generate a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGNMENT, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.

 - args.outputs.sprites: An array. The values generate a sprite.
   The parameters are [X, Y, WIDTH, HEIGHT, IMAGE PATH]
   For more information about sprites, go to mygame/documentation/05-sprites.md.

 - args.outputs.solids: An array. The values generate a solid.
   The parameters are [X, Y, WIDTH, HEIGHT, RED, GREEN, BLUE]
   For more information about solids, go to mygame/documentation/03-solids-and-borders.md.

 - args.outputs.lines: An array. The values generate a line.
   The parameters are [X, Y, X2, Y2, RED, GREEN, BLUE]
   For more information about lines, go to mygame/documentation/04-lines.md.

 - args.state.new_entity: Used when we want to create a new object, like a sprite or button.
   In this sample app, new_entity is used to create a new button that clears the grid.
   (Remember, you can use state to define ANY property and it will be retained across frames.)

=end

# This sample app shows an empty grid that the user can paint in. There are different image tiles that
# the user can use to fill the grid, and the "Clear" button can be pressed to clear the grid boxes.

class TileEditor
  attr_accessor :inputs, :state, :outputs, :grid, :args

  # Runs all the methods necessary for the game to function properly.
  def tick
    defaults
    render
    check_click
    draw_buttons
  end

  # Sets default values
  # Initialization only happens in the first frame
  # NOTE: The values of some of these variables may seem confusingly large at first.
  # The gridSize is 1600 but it seems a lot smaller on the screen, for example.
  # But keep in mind that by using the "W", "A", "S", and "D" keys, you can
  # move the grid's view in all four directions for more grid spaces.
  def defaults
    state.tileCords      ||= []
    state.tileQuantity   ||= 6
    state.tileSize       ||= 50
    state.tileSelected   ||= 1
    state.tempX          ||= 50
    state.tempY          ||= 500
    state.speed          ||= 4
    state.centerX        ||= 4000
    state.centerY        ||= 4000
    state.originalCenter ||= [state.centerX, state.centerY]
    state.gridSize       ||= 1600
    state.lineQuantity   ||= 50
    state.increment      ||= state.gridSize / state.lineQuantity
    state.gridX          ||= []
    state.gridY          ||= []
    state.filled_squares ||= []
    state.grid_border    ||= [390, 140, 500, 500]

    get_grid unless state.tempX == 0 # calls get_grid in the first frame only
    determineTileCords unless state.tempX == 0 # calls determineTileCords in first frame
    state.tempX = 0 # sets tempX to 0; the two methods aren't called again
  end

  # Calculates the placement of lines or separators in the grid
  def get_grid
    curr_x = state.centerX - (state.gridSize / 2) # starts at left of grid
    deltaX = state.gridSize / state.lineQuantity # finds distance to place vertical lines evenly through width of grid
    (state.lineQuantity + 2).times do
      state.gridX << curr_x # adds curr_x to gridX collection
      curr_x += deltaX # increment curr_x by the distance between vertical lines
    end

    curr_y = state.centerY - (state.gridSize / 2) # starts at bottom of grid
    deltaY = state.gridSize / state.lineQuantity # finds distance to place horizontal lines evenly through height of grid
    (state.lineQuantity + 2).times do
      state.gridY << curr_y # adds curr_y to gridY collection
      curr_y += deltaY # increments curr_y to distance between horizontal lines
    end
  end

  # Determines coordinate positions of patterned tiles (on the left side of the grid)
  def determineTileCords
    state.tempCounter ||= 1 # initializes tempCounter to 1
    state.tileQuantity.times do # there are 6 different kinds of tiles
      state.tileCords += [[state.tempX, state.tempY, state.tempCounter]] # adds tile definition to collection
      state.tempX += 75 # increments tempX to put horizontal space between the patterned tiles
      state.tempCounter += 1 # increments tempCounter
      if state.tempX > 200 # if tempX exceeds 200 pixels
        state.tempX = 50 # a new row of patterned tiles begins
        state.tempY -= 75 # the new row is 75 pixels lower than the previous row
      end
    end
  end

  # Outputs objects (grid, tiles, etc) onto the screen
  def render
    outputs.sprites << state.tileCords.map do # outputs tileCords collection using images in sprites folder
      |x, y, order|
      [x, y, state.tileSize, state.tileSize, 'sprites/image' + order.to_s + ".png"]
    end
    outputs.solids << [0, 0, 1280, 720, 255, 255, 255] # outputs white background
    add_grid # outputs grid
    print_title # outputs title and current tile pattern
  end

  # Creates a grid by outputting vertical and horizontal grid lines onto the screen.
  # Outputs sprites for the filled_squares collection onto the screen.
  def add_grid

    # Outputs the grid's border.
    outputs.borders << state.grid_border
    temp = 0

    # Before looking at the code that outputs the vertical and horizontal lines in the
    # grid, take note of the fact that:
    # grid_border[1] refers to the border's bottom line (running horizontally),
    # grid_border[2] refers to the border's top line (running (horizontally),
    # grid_border[0] refers to the border's left line (running vertically),
    # and grid_border[3] refers to the border's right line (running vertically).

    #           [2]
    #       ----------
    #       |        |
    # [0]   |        | [3]
    #       |        |
    #       ----------
    #           [1]

    # Calculates the positions and outputs the x grid lines in the color gray.
    state.gridX.map do # perform an action on all elements of the gridX collection
      |x|
      temp += 1 # increment temp

      # if x's value is greater than (or equal to) the x value of the border's left side
      # and less than (or equal to) the x value of the border's right side
      if x >= state.centerX - (state.grid_border[2] / 2) && x <= state.centerX + (state.grid_border[2] / 2)
        delta = state.centerX - 640
        # vertical lines have the same starting and ending x positions
        # starting y and ending y positions lead from the bottom of the border to the top of the border
        outputs.lines << [x - delta, state.grid_border[1], x - delta, state.grid_border[1] + state.grid_border[2], 150, 150, 150] # sets definition of vertical line and outputs it
      end
    end
    temp = 0

    # Calculates the positions and outputs the y grid lines in the color gray.
    state.gridY.map do # perform an action on all elements of the gridY collection
      |y|
      temp += 1 # increment temp

      # if y's value is greater than (or equal to) the y value of the border's bottom side
      # and less than (or equal to) the y value of the border's top side
      if y >= state.centerY - (state.grid_border[3] / 2) && y <= state.centerY + (state.grid_border[3] / 2)
        delta = state.centerY - 393
        # horizontal lines have the same starting and ending y positions
        # starting x and ending x positions lead from the left side of the border to the right side of the border
        outputs.lines << [state.grid_border[0], y - delta, state.grid_border[0] + state.grid_border[3], y - delta, 150, 150, 150] # sets definition of horizontal line and outputs it
      end
    end

    # Sets values and outputs sprites for the filled_squares collection.
    state.filled_squares.map do # perform an action on every element of the filled_squares collection
      |x, y, w, h, sprite|
        # if x's value is greater than (or equal to) the x value of 17 pixels to the left of the border's left side
        # and less than (or equal to) the x value of the border's right side
        # and y's value is greater than (or equal to) the y value of the border's bottom side
        # and less than (or equal to) the y value of 25 pixels above the border's top side
        # NOTE: The allowance of 17 pixels and 25 pixels is due to the fact that a grid box may be slightly cut off or
        # not entirely visible in the grid's view (until it is moved using "W", "A", "S", "D")
        if x >= state.centerX - (state.grid_border[2] / 2) - 17 && x <= state.centerX + (state.grid_border[2] / 2) &&
           y >= state.centerY - (state.grid_border[3] / 2) && y <= state.centerY + (state.grid_border[3] / 2) + 25
          # calculations done to place sprites in grid spaces that are meant to filled in
          # mess around with the x and y values and see how the sprite placement changes
          outputs.sprites << [x - state.centerX + 630, y - state.centerY + 360, w, h, sprite]
        end
      end

      # outputs a white solid along the left side of the grid (change the color and you'll be able to see it against the white background)
      # state.increment subtracted in x parameter because solid's position is denoted by bottom left corner
      # state.increment subtracted in y parameter to avoid covering the title label
      outputs.primitives << [state.grid_border[0] - state.increment,
                             state.grid_border[1] - state.increment, state.increment, state.grid_border[3] + (state.increment * 2),
                             255, 255, 255].solid

      # outputs a white solid along the right side of the grid
      # state.increment subtracted from y parameter to avoid covering title label
      outputs.primitives << [state.grid_border[0] + state.grid_border[2],
                             state.grid_border[1] - state.increment, state.increment, state.grid_border[3] + (state.increment * 2),
                             255, 255, 255].solid

      # outputs a white solid along the bottom of the grid
      # state.increment subtracted from y parameter to avoid covering last row of grid boxes
      outputs.primitives << [state.grid_border[0] - state.increment, state.grid_border[1] - state.increment,
                             state.grid_border[2] + (2 * state.increment), state.increment, 255, 255, 255].solid

      # outputs a white solid along the top of the grid
      outputs.primitives << [state.grid_border[0] - state.increment, state.grid_border[1] + state.grid_border[3],
                             state.grid_border[2] + (2 * state.increment), state.increment, 255, 255, 255].solid

  end

  # Outputs title and current tile pattern
  def print_title
    outputs.labels << [640, 700, 'Mouse to Place Tile, WASD to Move Around', 7, 1] # title label
    outputs.lines << horizontal_separator(660, 0, 1280) # outputs horizontal separator
    outputs.labels << [1050, 500, 'Current:', 3, 1] # outputs Current label
    outputs.sprites << [1110, 474, state.tileSize / 2, state.tileSize / 2, 'sprites/image' + state.tileSelected.to_s + ".png"] # outputs sprite of current tile pattern using images in sprites folder; output is half the size of a tile
  end

  # Sets the starting position, ending position, and color for the horizontal separator.
  def horizontal_separator y, x, x2
    [x, y, x2, y, 150, 150, 150] # definition of separator; horizontal line means same starting/ending y
  end

  # Checks if the mouse is being clicked or dragged
  def check_click
    if inputs.keyboard.key_down.r # if the "r" key is pressed down
      $dragon.reset
    end

    if inputs.mouse.down #is mouse up or down?
      state.mouse_held = true
      if inputs.mouse.position.x < state.grid_border[0] # if mouse's x position is inside the grid's borders
        state.tileCords.map do # perform action on all elements of tileCords collection
          |x, y, order|
          # if mouse's x position is greater than (or equal to) the starting x position of a tile
          # and the mouse's x position is also less than (or equal to) the ending x position of that tile,
          # and the mouse's y position is greater than (or equal to) the starting y position of that tile,
          # and the mouse's y position is also less than (or equal to) the ending y position of that tile,
          # (BASICALLY, IF THE MOUSE'S POSITION IS WITHIN THE STARTING AND ENDING POSITIONS OF A TILE)
          if inputs.mouse.position.x >= x && inputs.mouse.position.x <= x + state.tileSize &&
             inputs.mouse.position.y >= y && inputs.mouse.position.y <= y + state.tileSize
            state.tileSelected = order # that tile is selected
          end
        end
      end
    elsif inputs.mouse.up # otherwise, if the mouse is in the "up" state
      state.mouse_held = false # mouse is not held down or dragged
      state.mouse_dragging = false
    end

    if state.mouse_held &&    # mouse needs to be down
       !inputs.mouse.click &&     # must not be first click
       ((inputs.mouse.previous_click.point.x - inputs.mouse.position.x).abs > 15 ||
        (inputs.mouse.previous_click.point.y - inputs.mouse.position.y).abs > 15) # Need to move 15 pixels before "drag"
      state.mouse_dragging = true
    end

    # if mouse is clicked inside grid's border, search_lines method is called with click input type
    if ((inputs.mouse.click) && (inputs.mouse.click.point.inside_rect? state.grid_border))
      search_lines(inputs.mouse.click.point, :click)

    # if mouse is dragged inside grid's border, search_lines method is called with drag input type
    elsif ((state.mouse_dragging) && (inputs.mouse.position.inside_rect? state.grid_border))
      search_lines(inputs.mouse.position, :drag)
    end

    # Changes grid's position on screen by moving it up, down, left, or right.

    # centerX is incremented by speed if the "d" key is pressed and if that sum is less than
    # the original left side of the center plus half the grid, minus half the top border of grid.
    # MOVES GRID RIGHT (increasing x)
    state.centerX += state.speed if inputs.keyboard.key_held.d &&
                                    (state.centerX + state.speed) < state.originalCenter[0] + (state.gridSize / 2) - (state.grid_border[2] / 2)
    # centerX is decremented by speed if the "a" key is pressed and if that difference is greater than
    # the original left side of the center minus half the grid, plus half the top border of grid.
    # MOVES GRID LEFT (decreasing x)
    state.centerX -= state.speed if inputs.keyboard.key_held.a &&
                                    (state.centerX - state.speed) > state.originalCenter[0] - (state.gridSize / 2) + (state.grid_border[2] / 2)
    # centerY is incremented by speed if the "w" key is pressed and if that sum is less than
    # the original bottom of the center plus half the grid, minus half the right border of grid.
    # MOVES GRID UP (increasing y)
    state.centerY += state.speed if inputs.keyboard.key_held.w &&
                                    (state.centerY + state.speed) < state.originalCenter[1] + (state.gridSize / 2) - (state.grid_border[3] / 2)
    # centerY is decremented by speed if the "s" key is pressed and if the difference is greater than
    # the original bottom of the center minus half the grid, plus half the right border of grid.
    # MOVES GRID DOWN (decreasing y)
    state.centerY -= state.speed if inputs.keyboard.key_held.s &&
                                    (state.centerY - state.speed) > state.originalCenter[1] - (state.gridSize / 2) + (state.grid_border[3] / 2)
  end

  # Performs calculations on the gridX and gridY collections, and sets values.
  # Sets the definition of a grid box, including the image that it is filled with.
  def search_lines (point, input_type)
    point.x += state.centerX - 630 # increments x and y
    point.y += state.centerY - 360
    findX = 0
    findY = 0
    increment = state.gridSize / state.lineQuantity # divides grid by number of separators

    state.gridX.map do # perform an action on every element of collection
      |x|
      # findX increments x by 10 if point.x is less than that sum and findX is currently 0
      findX = x + 10 if point.x < (x + 10) && findX == 0
    end

    state.gridY.map do
      |y|
      # findY is set to y if point.y is less than that value and findY is currently 0
      findY = y if point.y < (y) && findY == 0
    end
    # position of a box is denoted by bottom left corner, which is why the increment is being subtracted
    grid_box = [findX - (increment.ceil), findY - (increment.ceil), increment.ceil, increment.ceil,
                "sprites/image" + state.tileSelected.to_s + ".png"] # sets sprite definition

    if input_type == :click # if user clicks their mouse
      if state.filled_squares.include? grid_box # if grid box is already filled in
        state.filled_squares.delete grid_box # box is cleared and removed from filled_squares
      else
        state.filled_squares << grid_box # otherwise, box is filled in and added to filled_squares
      end
    elsif input_type == :drag # if user drags mouse
      unless state.filled_squares.include? grid_box # unless grid box dragged over is already filled in
        state.filled_squares << grid_box # box is filled in and added to filled_squares
      end
    end
  end

  # Creates a "Clear" button using labels and borders.
  def draw_buttons
    x, y, w, h = 390, 50, 240, 50
    state.clear_button        ||= state.new_entity(:button_with_fade)

    # x and y positions are set to display "Clear" label in center of the button
    # Try changing first two parameters to simply x, y and see what happens to the text placement
    state.clear_button.label  ||= [x + w.half, y + h.half + 10, "Clear", 0, 1]
    state.clear_button.border ||= [x, y, w, h] # definition of button's border

    # If the mouse is clicked inside the borders of the clear button
    if inputs.mouse.click && inputs.mouse.click.point.inside_rect?(state.clear_button.border)
      state.clear_button.clicked_at = inputs.mouse.click.created_at # value is frame of mouse click
      state.filled_squares.clear # filled squares collection is emptied (squares are cleared)
      inputs.mouse.previous_click = nil # no previous click
    end

    outputs.labels << state.clear_button.label # outputs clear button
    outputs.borders << state.clear_button.border

    # When the clear button is clicked, the color of the button changes
    # and the transparency changes, as well. If you change the time from
    # 0.25.seconds to 1.25.seconds or more, the change will last longer.
    if state.clear_button.clicked_at
      outputs.solids << [x, y, w, h, 0, 180, 80, 255 * state.clear_button.clicked_at.ease(0.25.seconds, :flip)]
    end
  end
end

$tile_editor = TileEditor.new

def tick args
  $tile_editor.inputs = args.inputs
  $tile_editor.grid = args.grid
  $tile_editor.args = args
  $tile_editor.outputs = args.outputs
  $tile_editor.state = args.state
  $tile_editor.tick
  tick_instructions args, "Roll your own tile editor. CLICK to select a sprite. CLICK in grid to place sprite. WASD to move around."
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Genre Dungeon Crawl link

Classics Jam - main.rb link

# ./samples/99_genre_dungeon_crawl/classics_jam/app/main.rb
class Game
  attr_gtk

  def tick
    defaults
    render
    input
    calc
  end

  def defaults
    player.x              ||= 640
    player.y              ||= 360
    player.w              ||= 16
    player.h              ||= 16
    player.attacked_at    ||= -1
    player.angle          ||= 0
    player.future_player  ||= future_player_position 0, 0
    player.projectiles    ||= []
    player.damage         ||= 0
    state.level           ||= create_level level_one_template
  end

  def render
    outputs.sprites << level.walls.map do |w|
      w.merge(path: 'sprites/square/gray.png')
    end

    outputs.sprites << level.spawn_locations.map do |s|
      s.merge(path: 'sprites/square/blue.png')
    end

    outputs.sprites << player.projectiles.map do |p|
      p.merge(path: 'sprites/square/blue.png')
    end

    outputs.sprites << level.enemies.map do |e|
      e.merge(path: 'sprites/square/red.png')
    end

    outputs.sprites << player.merge(path: 'sprites/circle/green.png', angle: player.angle)

    outputs.labels << { x: 30, y: 30.from_top, text: "damage: #{player.damage || 0}" }
  end

  def input
    player.angle = inputs.directional_angle || player.angle
    if inputs.controller_one.key_down.a || inputs.keyboard.key_down.space
      player.attacked_at = Kernel.tick_count
    end
  end

  def calc
    calc_player
    calc_projectiles
    calc_enemies
    calc_spawn_locations
  end

  def calc_player
    if player.attacked_at == Kernel.tick_count
      player.projectiles << { at: Kernel.tick_count,
                              x: player.x,
                              y: player.y,
                              angle: player.angle,
                              w: 4,
                              h: 4 }.center_inside_rect(player)
    end

    if player.attacked_at.elapsed_time > 5
      future_player = future_player_position inputs.left_right * 2, inputs.up_down * 2
      future_player_collision = future_collision player, future_player, level.walls
      player.x = future_player_collision.x if !future_player_collision.dx_collision
      player.y = future_player_collision.y if !future_player_collision.dy_collision
    end
  end

  def calc_projectile_collisions entities
    entities.each do |e|
      e.damage ||= 0
      player.projectiles.each do |p|
        if !p.collided && (p.intersect_rect? e)
          p.collided = true
          e.damage  += 1
        end
      end
    end
  end

  def calc_projectiles
    player.projectiles.map! do |p|
      dx, dy = p.angle.vector 10
      p.merge(x: p.x + dx, y: p.y + dy)
    end

    calc_projectile_collisions level.walls + level.enemies + level.spawn_locations
    player.projectiles.reject! { |p| p.at.elapsed_time > 10000 }
    player.projectiles.reject! { |p| p.collided }
    level.enemies.reject! { |e| e.damage > e.hp }
    level.spawn_locations.reject! { |s| s.damage > s.hp }
  end

  def calc_enemies
    level.enemies.map! do |e|
      dx =  0
      dx =  1 if e.x < player.x
      dx = -1 if e.x > player.x
      dy =  0
      dy =  1 if e.y < player.y
      dy = -1 if e.y > player.y
      future_e           = future_entity_position dx, dy, e
      future_e_collision = future_collision e, future_e, level.enemies + level.walls
      e.next_x = e.x
      e.next_y = e.y
      e.next_x = future_e_collision.x if !future_e_collision.dx_collision
      e.next_y = future_e_collision.y if !future_e_collision.dy_collision
      e
    end

    level.enemies.map! do |e|
      e.x = e.next_x
      e.y = e.next_y
      e
    end

    level.enemies.each do |e|
      player.damage += 1 if e.intersect_rect? player
    end
  end

  def calc_spawn_locations
    level.spawn_locations.map! do |s|
      s.merge(countdown: s.countdown - 1)
    end
    level.spawn_locations
         .find_all { |s| s.countdown.neg? }
         .each do |s|
      s.countdown = s.rate
      s.merge(countdown: s.rate)
      new_enemy = create_enemy s
      if !(level.enemies.find { |e| e.intersect_rect? new_enemy })
        level.enemies << new_enemy
      end
    end
  end

  def create_enemy spawn_location
    to_cell(spawn_location.ordinal_x, spawn_location.ordinal_y).merge hp: 2
  end

  def create_level level_template
    {
      walls:           level_template.walls.map { |w| to_cell(w.ordinal_x, w.ordinal_y).merge(w) },
      enemies:         [],
      spawn_locations: level_template.spawn_locations.map { |s| to_cell(s.ordinal_x, s.ordinal_y).merge(s) }
    }
  end

  def level_one_template
    {
      walls:           [{ ordinal_x: 25, ordinal_y: 20},
                        { ordinal_x: 25, ordinal_y: 21},
                        { ordinal_x: 25, ordinal_y: 22},
                        { ordinal_x: 25, ordinal_y: 23}],
      spawn_locations: [{ ordinal_x: 10, ordinal_y: 10, rate: 120, countdown: 0, hp: 5 }]
    }
  end

  def player
    state.player ||= {}
  end

  def level
    state.level  ||= {}
  end

  def future_collision entity, future_entity, others
    dx_collision = others.find { |o| o != entity && (o.intersect_rect? future_entity.dx) }
    dy_collision = others.find { |o| o != entity && (o.intersect_rect? future_entity.dy) }

    {
      dx_collision: dx_collision,
      x: future_entity.dx.x,
      dy_collision: dy_collision,
      y: future_entity.dy.y
    }
  end

  def future_entity_position dx, dy, entity
    {
      dx:   entity.merge(x: entity.x + dx),
      dy:   entity.merge(y: entity.y + dy),
      both: entity.merge(x: entity.x + dx, y: entity.y + dy)
    }
  end

  def future_player_position  dx, dy
    future_entity_position dx, dy, player
  end

  def to_cell ordinal_x, ordinal_y
    { x: ordinal_x * 16, y: ordinal_y * 16, w: 16, h: 16 }
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

$gtk.reset
$game = nil

Genre Fighting link

Special Move Inputs - main.rb link

# ./samples/99_genre_fighting/01_special_move_inputs/app/main.rb
def tick args
  #tick_instructions args, "Use LEFT and RIGHT arrow keys to move and SPACE to jump."
  defaults args
  render args
  input args
  calc args
end

# sets default values and creates empty collections
# initialization only happens in the first frame
def defaults args
  fiddle args

  Kernel.tick_count = Kernel.tick_count
  args.state.bridge_top = 128
  args.state.player.x  ||= 0                        # initializes player's properties
  args.state.player.y  ||= args.state.bridge_top
  args.state.player.w  ||= 64
  args.state.player.h  ||= 64
  args.state.player.dy ||= 0
  args.state.player.dx ||= 0
  args.state.player.r  ||= 0
  args.state.game_over_at ||= 0
  args.state.animation_time ||=0

  args.state.timeleft ||=0
  args.state.timeright ||=0
  args.state.lastpush ||=0

  args.state.inputlist ||=  ["j","k","l"]
end

# sets enemy, player, hammer values
def fiddle args
  args.state.gravity                     = -0.5
  args.state.player_jump_power           = 10      # sets player values
  args.state.player_jump_power_duration  = 5
  args.state.player_max_run_speed        = 20
  args.state.player_speed_slowdown_rate  = 0.9
  args.state.player_acceleration         = 0.9
end

# outputs objects onto the screen
def render args
  if (args.state.player.dx < 0.01) && (args.state.player.dx > -0.01)
    args.state.player.dx = 0
  end

  #move list
  (args.layout.rect_group row: 0, col_from_right: 8, drow: 0.3,
                          merge: { vertical_alignment_enum: 0, size_enum: -2 },
                          group: [
                            { text: "move:             WASD" },
                            { text: "jump:             Space" },
                            { text: "attack forwards:  J (while on ground" },
                            { text: "attack upwards:   K (while on groud)" },
                            { text: "attack backwards: J (while on ground and holding A)" },
                            { text: "attack downwards: K (while in air)" },
                            { text: "dash attack:      J, K in quick succession." },
                            { text: "shield: hold      J, K at the same time." },
                            { text: "dash backwards:   A, A in quick succession." },
                          ]).into args.outputs.labels

  # registered moves
  args.outputs.labels << { x: 0.to_layout_col,
                           y: 0.to_layout_row,
                           text: "input history",
                           size_enum: -2,
                           vertical_alignment_enum: 0 }

  (args.state.inputlist.take(5)).map do |s|
    { text: s, size_enum: -2, vertical_alignment_enum: 0 }
  end.yield_self do |group|
    (args.layout.rect_group row: 0.3, col: 0, drow: 0.3, group: group).into args.outputs.labels
  end


  #sprites
  player = [args.state.player.x, args.state.player.y,
            args.state.player.w, args.state.player.h,
            "sprites/square/white.png",
            args.state.player.r]

  playershield = [args.state.player.x - 20, args.state.player.y - 10,
                  args.state.player.w + 20, args.state.player.h + 20,
                  "sprites/square/blue.png",
                  args.state.player.r,
                  0]

  playerjab = [args.state.player.x + 32, args.state.player.y,
               args.state.player.w, args.state.player.h,
               "sprites/isometric/indigo.png",
               args.state.player.r,
               0]

  playerupper = [args.state.player.x, args.state.player.y + 32,
                 args.state.player.w, args.state.player.h,
                 "sprites/isometric/indigo.png",
                 args.state.player.r+90,
                 0]

  if ((Kernel.tick_count - args.state.lastpush) <= 15)
    if (args.state.inputlist[0] == "<<")
      player = [args.state.player.x, args.state.player.y,
                args.state.player.w, args.state.player.h,
                "sprites/square/yellow.png", args.state.player.r]
    end

    if (args.state.inputlist[0] == "shield")
      player = [args.state.player.x, args.state.player.y,
                args.state.player.w, args.state.player.h,
                "sprites/square/indigo.png", args.state.player.r]

      playershield = [args.state.player.x - 10, args.state.player.y - 10,
                      args.state.player.w + 20, args.state.player.h + 20,
                      "sprites/square/blue.png", args.state.player.r, 50]
    end

    if (args.state.inputlist[0] == "back-attack")
      playerjab = [args.state.player.x - 20, args.state.player.y,
                   args.state.player.w - 10, args.state.player.h,
                   "sprites/isometric/indigo.png", args.state.player.r, 255]
    end

    if (args.state.inputlist[0] == "forward-attack")
      playerjab = [args.state.player.x + 32, args.state.player.y,
                   args.state.player.w, args.state.player.h,
                   "sprites/isometric/indigo.png", args.state.player.r, 255]
    end

    if (args.state.inputlist[0] == "up-attack")
      playerupper = [args.state.player.x, args.state.player.y + 32,
                     args.state.player.w, args.state.player.h,
                     "sprites/isometric/indigo.png", args.state.player.r + 90, 255]
    end

    if (args.state.inputlist[0] == "dair")
      playerupper = [args.state.player.x, args.state.player.y - 32,
                     args.state.player.w, args.state.player.h,
                     "sprites/isometric/indigo.png", args.state.player.r + 90, 255]
    end

    if (args.state.inputlist[0] == "dash-attack")
      playerupper = [args.state.player.x, args.state.player.y + 32,
                     args.state.player.w, args.state.player.h,
                     "sprites/isometric/violet.png", args.state.player.r + 90, 255]

      playerjab = [args.state.player.x + 32, args.state.player.y,
                   args.state.player.w, args.state.player.h,
                   "sprites/isometric/violet.png", args.state.player.r, 255]
    end
  end

  args.outputs.sprites << playerjab
  args.outputs.sprites << playerupper
  args.outputs.sprites << player
  args.outputs.sprites << playershield

  args.outputs.solids << 20.map_with_index do |i| # uses 20 squares to form bridge
    [i * 64, args.state.bridge_top - 64, 64, 64]
  end
end

# Performs calculations to move objects on the screen
def calc args
  # Since velocity is the change in position, the change in x increases by dx. Same with y and dy.
  args.state.player.x  += args.state.player.dx
  args.state.player.y  += args.state.player.dy

  # Since acceleration is the change in velocity, the change in y (dy) increases every frame
  args.state.player.dy += args.state.gravity

  # player's y position is either current y position or y position of top of
  # bridge, whichever has a greater value
  # ensures that the player never goes below the bridge
  args.state.player.y  = args.state.player.y.greater(args.state.bridge_top)

  # player's x position is either the current x position or 0, whichever has a greater value
  # ensures that the player doesn't go too far left (out of the screen's scope)
  args.state.player.x  = args.state.player.x.greater(0)

  # player is not falling if it is located on the top of the bridge
  args.state.player.falling = false if args.state.player.y == args.state.bridge_top
  #args.state.player.rect = [args.state.player.x, args.state.player.y, args.state.player.h, args.state.player.w] # sets definition for player
end

# Resets the player by changing its properties back to the values they had at initialization
def reset_player args
  args.state.player.x = 0
  args.state.player.y = args.state.bridge_top
  args.state.player.dy = 0
  args.state.player.dx = 0
  args.state.enemy.hammers.clear # empties hammer collection
  args.state.enemy.hammer_queue.clear # empties hammer_queue
  args.state.game_over_at = Kernel.tick_count # game_over_at set to current frame (or passage of time)
end

# Processes input from the user to move the player
def input args
  if args.state.inputlist.length > 5
    args.state.inputlist.pop
  end

  should_process_special_move = (args.inputs.keyboard.key_down.j)           ||
                                (args.inputs.keyboard.key_down.k)           ||
                                (args.inputs.keyboard.key_down.a)           ||
                                (args.inputs.keyboard.key_down.d)           ||
                                (args.inputs.controller_one.key_down.y)     ||
                                (args.inputs.controller_one.key_down.x)     ||
                                (args.inputs.controller_one.key_down.left)  ||
                                (args.inputs.controller_one.key_down.right)

  if (should_process_special_move)
    if (args.inputs.keyboard.key_down.j && args.inputs.keyboard.key_down.k) ||
       (args.inputs.controller_one.key_down.x && args.inputs.controller_one.key_down.y)
      args.state.inputlist.unshift("shield")
    elsif (args.inputs.keyboard.key_down.k || args.inputs.controller_one.key_down.y) &&
          (args.state.inputlist[0] == "forward-attack") && ((Kernel.tick_count - args.state.lastpush) <= 15)
      args.state.inputlist.unshift("dash-attack")
      args.state.player.dx = 20
    elsif (args.inputs.keyboard.key_down.j && args.inputs.keyboard.a) ||
          (args.inputs.controller_one.key_down.x && args.inputs.controller_one.key_down.left)
      args.state.inputlist.unshift("back-attack")
    elsif ( args.inputs.controller_one.key_down.x || args.inputs.keyboard.key_down.j)
      args.state.inputlist.unshift("forward-attack")
    elsif (args.inputs.keyboard.key_down.k || args.inputs.controller_one.key_down.y) &&
          (args.state.player.y > 128)
      args.state.inputlist.unshift("dair")
    elsif (args.inputs.keyboard.key_down.k || args.inputs.controller_one.key_down.y)
      args.state.inputlist.unshift("up-attack")
    elsif (args.inputs.controller_one.key_down.left || args.inputs.keyboard.key_down.a) &&
          (args.state.inputlist[0] == "<") &&
          ((Kernel.tick_count - args.state.lastpush) <= 10)
      args.state.inputlist.unshift("<<")
      args.state.player.dx = -15
    elsif (args.inputs.controller_one.key_down.left || args.inputs.keyboard.key_down.a)
      args.state.inputlist.unshift("<")
      args.state.timeleft = Kernel.tick_count
    elsif (args.inputs.controller_one.key_down.right || args.inputs.keyboard.key_down.d)
      args.state.inputlist.unshift(">")
    end

    args.state.lastpush = Kernel.tick_count
  end

  if args.inputs.keyboard.space || args.inputs.controller_one.r2   # if the user presses the space bar
    args.state.player.jumped_at ||= Kernel.tick_count # jumped_at is set to current frame

    # if the time that has passed since the jump is less than the player's jump duration and
    # the player is not falling
    if args.state.player.jumped_at.elapsed_time < args.state.player_jump_power_duration && !args.state.player.falling
      args.state.player.dy = args.state.player_jump_power # change in y is set to power of player's jump
    end
  end

  # if the space bar is in the "up" state (or not being pressed down)
  if args.inputs.keyboard.key_up.space || args.inputs.controller_one.key_up.r2
    args.state.player.jumped_at = nil # jumped_at is empty
    args.state.player.falling = true # the player is falling
  end

  if args.inputs.left # if left key is pressed
    if args.state.player.dx < -5
      args.state.player.dx = args.state.player.dx
    else
      args.state.player.dx = -5
    end

  elsif args.inputs.right # if right key is pressed
    if args.state.player.dx > 5
      args.state.player.dx = args.state.player.dx
    else
      args.state.player.dx = 5
    end
  else
    args.state.player.dx *= args.state.player_speed_slowdown_rate # dx is scaled down
  end

  if ((args.state.player.dx).abs > 5) #&& ((Kernel.tick_count - args.state.lastpush) <= 10)
    args.state.player.dx *= 0.95
  end
end

def tick_instructions args, text, y = 715
  return if args.state.key_event_occurred
  if args.inputs.mouse.click ||
     args.inputs.keyboard.directional_vector ||
     args.inputs.keyboard.key_down.enter ||
     args.inputs.keyboard.key_down.space ||
     args.inputs.keyboard.key_down.escape
    args.state.key_event_occurred = true
  end

  args.outputs.debug << [0, y - 50, 1280, 60].solid
  args.outputs.debug << [640, y, text, 1, 1, 255, 255, 255].label
  args.outputs.debug << [640, y - 25, "(click to dismiss instructions)" , -2, 1, 255, 255, 255].label
end

Genre Lowrez link

Nokia 3310 - main.rb link

# ./samples/99_genre_lowrez/nokia_3310/app/main.rb
require 'app/nokia.rb'

def tick args
  # =======================================================================
  # ==== HELLO WORLD ======================================================
  # =======================================================================
  # Steps to get started:
  # 1. ~def tick args~ is the entry point for your game.
  # 2. There are quite a few code samples below, remove the "##"
  #    before each line and save the file to see the changes.
  # 3. 0,  0 is in bottom left and 83, 47 is in top right corner.
  # 4. Be sure to come to the discord channel if you need
  #    more help: [[http://discord.dragonruby.org]].

  # Commenting and uncommenting code:
  # - Add a "#" infront of lines to comment out code
  # - Remove the "#" infront of lines to comment out code

  # Invoke the hello_world subroutine/method
  hello_world args # <---- add a "#" to the beginning of the line to stop running this subroutine/method.

  # =======================================================================
  # ==== HOW TO RENDER A LABEL ============================================
  # =======================================================================

  # Uncomment the line below to invoke the how_to_render_a_label subroutine/method.
  # Note: The method is defined in this file with the signature ~def how_to_render_a_label args~
  #       Scroll down to the method to see the details.

  # Remove the "#" at the beginning of the line below
  # how_to_render_a_label args # <---- remove the "#" at the beginning of this line to run the method


  # =======================================================================
  # ==== HOW TO RENDER A FILLED SQUARE (SOLID) ============================
  # =======================================================================
  # Remove the "#" at the beginning of the line below
  # how_to_render_solids args


  # =======================================================================
  # ==== HOW TO RENDER AN UNFILLED SQUARE (BORDER) ========================
  # =======================================================================
  # Remove the "#" at the beginning of the line below
  # how_to_render_borders args


  # =======================================================================
  # ==== HOW TO RENDER A LINE =============================================
  # =======================================================================
  # Remove the "#" at the beginning of the line below
  # how_to_render_lines args


  # =======================================================================
  # == HOW TO RENDER A SPRITE =============================================
  # =======================================================================
  # Remove the "#" at the beginning of the line below
  # how_to_render_sprites args


  # =======================================================================
  # ==== HOW TO MOVE A SPRITE BASED OFF OF USER INPUT =====================
  # =======================================================================
  # Remove the "#" at the beginning of the line below
  # how_to_move_a_sprite args


  # =======================================================================
  # ==== HOW TO ANIMATE A SPRITE (SEPERATE PNGS) ==========================
  # =======================================================================
  # Remove the "#" at the beginning of the line below
  # how_to_animate_a_sprite args


  # =======================================================================
  # ==== HOW TO ANIMATE A SPRITE (SPRITE SHEET) ===========================
  # =======================================================================
  # Remove the "#" at the beginning of the line below
  # how_to_animate_a_sprite_sheet args


  # =======================================================================
  # ==== HOW TO DETERMINE COLLISION =============================================
  # =======================================================================
  # Remove the "#" at the beginning of the line below
  # how_to_determine_collision args


  # =======================================================================
  # ==== HOW TO CREATE BUTTONS ==================================================
  # =======================================================================
  # Remove the "#" at the beginning of the line below
  # how_to_create_buttons args

  # ==== The line below renders a debug grid, mouse information, and current tick
  # render_debug args
end

# =======================================================================
# ==== HELLO WORLD ======================================================
# =======================================================================
def hello_world args
  args.nokia.solids  << { x: 0, y: 64, w: 10, h: 10, r: 255 }

  args.nokia.labels  << {
    x: 42,
    y: 46,
    text: "nokia 3310 jam 3",
    size_enum: NOKIA_FONT_SM,
    alignment_enum: 1,
    r: 0,
    g: 0,
    b: 0,
    a: 255,
    font: NOKIA_FONT_PATH
  }

  args.nokia.sprites << {
    x: 42 - 10,
    y: 26 - 10,
    w: 20,
    h: 20,
    path: 'sprites/monochrome-ship.png',
    a: 255,
    angle: Kernel.tick_count % 360
  }
end

# =======================================================================
# ==== HOW TO RENDER A LABEL ============================================
# =======================================================================
def how_to_render_a_label args
  # NOTE: Text is aligned from the TOP LEFT corner

  # Render an EXTRA LARGE/XL label (remove the "#" in front of each line below)
  args.nokia.labels << { x: 0, y: 46, text: "Hello World",
                         size_enum: NOKIA_FONT_XL,
                         r: 0, g: 0, b: 0, a: 255,
                         font: NOKIA_FONT_PATH }

  # Render a LARGE/LG label (remove the "#" in front of each line below)
  args.nokia.labels << { x: 0, y: 29, text: "Hello World",
                          size_enum: NOKIA_FONT_LG,
                          r: 0, g: 0, b: 0, a: 255,
                          font: NOKIA_FONT_PATH }

  # Render a MEDIUM/MD label (remove the "#" in front of each line below)
  args.nokia.labels << { x: 0, y: 16, text: "Hello World",
                          size_enum: NOKIA_FONT_MD,
                          r: 0, g: 0, b: 0, a: 255,
                          font: NOKIA_FONT_PATH }

  # Render a SMALL/SM label (remove the "#" in front of each line below)
  args.nokia.labels << { x: 0, y: 7, text: "Hello World",
                          size_enum: NOKIA_FONT_SM,
                          r: 0, g: 0, b: 0, a: 255,
                          font: NOKIA_FONT_PATH }

  # You are provided args.nokia.default_label which returns a Hash that you
  # can ~merge~ properties with
  # Example 1
  args.nokia.labels << args.nokia
                            .default_label
                            .merge(text: "Default")

  # Example 2
  args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: 31,
                                   text: "Default")
end

# =============================================================================
# ==== HOW TO RENDER FILLED SQUARES (SOLIDS) ==================================
# =============================================================================
def how_to_render_solids args
  # Render a square at 0, 0 with a width and height of 1
  args.nokia.solids << { x: 0, y: 0, w: 1, h: 1 }

  # Render a square at 1, 1 with a width and height of 2
  args.nokia.solids << { x: 1, y: 1, w: 2, h: 2 }

  # Render a square at 3, 3 with a width and height of 3
  args.nokia.solids << { x: 3, y: 3, w: 3, h: 3 }

  # Render a square at 6, 6 with a width and height of 4
  args.nokia.solids << { x: 6, y: 6, w: 4, h: 4 }
end

# =============================================================================
# ==== HOW TO RENDER UNFILLED SQUARES (BORDERS) ===============================
# =============================================================================
def how_to_render_borders args
  # Render a square at 0, 0 with a width and height of 3
  args.nokia.borders << { x: 0, y: 0, w: 3, h: 3, a: 255 }

  # Render a square at 3, 3 with a width and height of 3
  args.nokia.borders << { x: 3, y: 3, w: 4, h: 4, a: 255 }

  # Render a square at 5, 5 with a width and height of 4
  args.nokia.borders << { x: 7, y: 7, w: 5, h: 5, a: 255 }
end

# =============================================================================
# ==== HOW TO RENDER A LINE ===================================================
# =============================================================================
def how_to_render_lines args
  # Render a horizontal line at the bottom
  args.nokia.lines << { x: 0, y: 0, x2: 83, y2:  0 }

  # Render a vertical line at the left
  args.nokia.lines << { x: 0, y: 0, x2:  0, y2: 47 }

  # Render a diagonal line starting from the bottom left and going to the top right
  args.nokia.lines << { x: 0, y: 0, x2: 83, y2: 47 }
end

# =============================================================================
# == HOW TO RENDER A SPRITE ===================================================
# =============================================================================
def how_to_render_sprites args
  # Loop 10 times and create 10 sprites in 10 positions
  # Render a sprite at the bottom left with a width and height of 5 and a path of 'sprites/monochrome-ship.png'
  10.times do |i|
    args.nokia.sprites << {
      x: i * 8.4,
      y: i * 4.8,
      w: 5,
      h: 5,
      path: 'sprites/monochrome-ship.png'
    }
  end

  # Given an array of positions create sprites
  positions = [
    { x: 20, y: 32 },
    { x: 45, y: 15 },
    { x: 72, y: 23 },
  ]

  positions.each do |position|
    # use Ruby's ~Hash#merge~ function to create a sprite
    args.nokia.sprites << position.merge(path: 'sprites/monochrome-ship.png',
                                          w: 5,
                                          h: 5)
  end
end

# =============================================================================
# ==== HOW TO ANIMATE A SPRITE (SEPERATE PNGS) ==========================
# =============================================================================
def how_to_animate_a_sprite args
  # STEP 1: Define when you want the animation to start. The animation in this case will start in 3 seconds
  start_animation_on_tick = 180

  # STEP 2: Get the frame_index given the start tick.
  sprite_index = start_animation_on_tick.frame_index count: 7,     # how many sprites?
                                                     hold_for: 8,  # how long to hold each sprite?
                                                     repeat: true  # should it repeat?

  # STEP 3: frame_index will return nil if the frame hasn't arrived yet
  if sprite_index
    # if the sprite_index is populated, use it to determine the sprite path and render it
    sprite_path  = "sprites/explosion-#{sprite_index}.png"
    args.nokia.sprites << { x: 42 - 16,
                             y: 47 - 32,
                             w: 32,
                             h: 32,
                             path: sprite_path }
  else
    # if the sprite_index is nil, render a countdown instead
    countdown_in_seconds = ((start_animation_on_tick - Kernel.tick_count) / 60).round(1)

    args.nokia.labels  << args.nokia
                               .default_label
                               .merge(x: 0,
                                      y: 18,
                                      text: "Count Down: #{countdown_in_seconds.to_sf}",
                                      alignment_enum: 0)
  end

  # render the current tick and the resolved sprite index
  args.nokia.labels  << args.nokia
                               .default_label
                               .merge(x: 0,
                                      y: 11,
                                      text: "Tick: #{Kernel.tick_count}")
  args.nokia.labels  << args.nokia
                               .default_label
                               .merge(x: 0,
                                      y: 5,
                                      text: "sprite_index: #{sprite_index}")
end

# =============================================================================
# ==== HOW TO ANIMATE A SPRITE (SPRITE SHEET) =================================
# =============================================================================
def how_to_animate_a_sprite_sheet args
  # STEP 1: Define when you want the animation to start. The animation in this case will start in 3 seconds
  start_animation_on_tick = 180

  # STEP 2: Get the frame_index given the start tick.
  sprite_index = start_animation_on_tick.frame_index count: 7,     # how many sprites?
                                                     hold_for: 8,  # how long to hold each sprite?
                                                     repeat: true  # should it repeat?

  # STEP 3: frame_index will return nil if the frame hasn't arrived yet
  if sprite_index
    # if the sprite_index is populated, use it to determine the source rectangle and render it
    args.nokia.sprites << {
      x: 42 - 16,
      y: 47 - 32,
      w: 32,
      h: 32,
      path:  "sprites/explosion-sheet.png",
      source_x: 32 * sprite_index,
      source_y: 0,
      source_w: 32,
      source_h: 32
    }
  else
    # if the sprite_index is nil, render a countdown instead
    countdown_in_seconds = ((start_animation_on_tick - Kernel.tick_count) / 60).round(1)

    args.nokia.labels  << args.nokia
                               .default_label
                               .merge(x: 0,
                                      y: 18,
                                      text: "Count Down: #{countdown_in_seconds.to_sf}",
                                      alignment_enum: 0)
  end

  # render the current tick and the resolved sprite index
  args.nokia.labels  << args.nokia
                               .default_label
                               .merge(x: 0,
                                      y: 11,
                                      text: "tick: #{Kernel.tick_count}")
  args.nokia.labels  << args.nokia
                               .default_label
                               .merge(x: 0,
                                      y: 5,
                                      text: "sprite_index: #{sprite_index}")
end

# =============================================================================
# ==== HOW TO STORE STATE, ACCEPT INPUT, AND RENDER SPRITE BASED OFF OF STATE =
# =============================================================================
def how_to_move_a_sprite args
  args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: 42,
                                   y: 46, text: "Use Arrow Keys",
                                   alignment_enum: 1)

  args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: 42,
                                   y: 41, text: "Or WASD",
                                   alignment_enum: 1)

  args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: 42,
                                   y: 36, text: "Or Click",
                                   alignment_enum: 1)

  # set the initial values for x and y using ||= ("or equal operator")
  args.state.ship.x ||= 0
  args.state.ship.y ||= 0

  # if a mouse click occurs, update the ship's x and y to be the location of the click
  if args.nokia.mouse_click
    args.state.ship.x = args.nokia.mouse_click.x
    args.state.ship.y = args.nokia.mouse_click.y
  end

  # if a or left arrow is pressed/held, decrement the ships x position
  if args.nokia.keyboard.left
    args.state.ship.x -= 1
  end

  # if d or right arrow is pressed/held, increment the ships x position
  if args.nokia.keyboard.right
    args.state.ship.x += 1
  end

  # if s or down arrow is pressed/held, decrement the ships y position
  if args.nokia.keyboard.down
    args.state.ship.y -= 1
  end

  # if w or up arrow is pressed/held, increment the ships y position
  if args.nokia.keyboard.up
    args.state.ship.y += 1
  end

  # render the sprite to the screen using the position stored in args.state.ship
  args.nokia.sprites << {
    x: args.state.ship.x,
    y: args.state.ship.y,
    w: 5,
    h: 5,
    path: 'sprites/monochrome-ship.png',
    # parameters beyond this point are optional
    angle: 0, # Note: rotation angle is denoted in degrees NOT radians
    r: 255,
    g: 255,
    b: 255,
    a: 255
  }
end

# =======================================================================
# ==== HOW TO DETERMINE COLLISION =======================================
# =======================================================================
def how_to_determine_collision args
  # Render the instructions
  args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: 42,
                                   y: 46, text: "Click Anywhere",
                                   alignment_enum: 1)

  # if a mouse click occurs:
  # - set ship_one if it isn't set
  # - set ship_two if it isn't set
  # - otherwise reset ship one and ship two
  if args.nokia.mouse_click
    # is ship_one set?
    if !args.state.ship_one
      args.state.ship_one = { x: args.nokia.mouse_click.x - 5,
                              y: args.nokia.mouse_click.y - 5,
                              w: 10,
                              h: 10 }
    # is ship_one set?
    elsif !args.state.ship_two
      args.state.ship_two = { x: args.nokia.mouse_click.x - 5,
                              y: args.nokia.mouse_click.y - 5,
                              w: 10,
                              h: 10 }
    # should we reset?
    else
      args.state.ship_one = nil
      args.state.ship_two = nil
    end
  end

  # render ship one if it's set
  if args.state.ship_one
    # use Ruby's .merge method which is available on ~Hash~ to set the sprite and alpha
    # render ship one
    args.nokia.sprites << args.state.ship_one.merge(path: 'sprites/monochrome-ship.png')
  end

  if args.state.ship_two
    # use Ruby's .merge method which is available on ~Hash~ to set the sprite and alpha
    # render ship two
    args.nokia.sprites << args.state.ship_two.merge(path: 'sprites/monochrome-ship.png')
  end

  # if both ship one and ship two are set, then determine collision
  if args.state.ship_one && args.state.ship_two
    # collision is determined using the intersect_rect? method
    if args.state.ship_one.intersect_rect? args.state.ship_two
      # if collision occurred, render the words collision!
      args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: 42,
                                   y: 5,
                                   text: "Collision!",
                                   alignment_enum: 1)
    else
      # if collision occurred, render the words no collision.
      args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: 42,
                                   y: 5,
                                   text: "No Collision.",
                                   alignment_enum: 1)
    end
  else
    # if both ship one and ship two aren't set, then render --
      args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: 42,
                                   y: 6,
                                   text: "--",
                                   alignment_enum: 1)
  end
end

# =============================================================================
# ==== HOW TO CREATE BUTTONS ==================================================
# =============================================================================
def how_to_create_buttons args
  # Define a button style
  args.state.button_style = { w: 82, h: 10, }

  # Render instructions
  args.state.button_message ||= "Press a Button!"
  args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: 42,
                                   y: 82,
                                   text: args.state.button_message,
                                   alignment_enum: 1)


  # Creates button one using a border and a label
  args.state.button_one_border = args.state.button_style.merge( x: 1, y: 32)
  args.nokia.borders << args.state.button_one_border
  args.nokia.labels  << args.nokia
                             .default_label
                             .merge(x: args.state.button_one_border.x + 2,
                                    y: args.state.button_one_border.y + NOKIA_FONT_SM_HEIGHT + 2,
                                    text: "Button One")

  # Creates button two using a border and a label
  args.state.button_two_border = args.state.button_style.merge( x: 1, y: 20)

  args.nokia.borders << args.state.button_two_border
  args.nokia.labels << args.nokia
                            .default_label
                            .merge(x: args.state.button_two_border.x + 2,
                                   y: args.state.button_two_border.y + NOKIA_FONT_SM_HEIGHT + 2,
                                   text: "Button Two")

  # Initialize the state variable that tracks which button was clicked to "" (empty stringI
  args.state.last_button_clicked ||= "--"

  # If a click occurs, check to see if either button one, or button two was clicked
  # using the inside_rect? method of the mouse
  # set args.state.last_button_clicked accordingly
  if args.nokia.mouse_click
    if args.nokia.mouse_click.inside_rect? args.state.button_one_border
      args.state.last_button_clicked = "One Clicked!"
    elsif args.nokia.mouse_click.inside_rect? args.state.button_two_border
      args.state.last_button_clicked = "Two Clicked!"
    else
      args.state.last_button_clicked = "--"
    end
  end

  # Render the current value of args.state.last_button_clicked
  args.nokia.labels << args.nokia
                             .default_label
                             .merge(x: 42,
                                    y: 5,
                                    text: args.state.last_button_clicked,
                                    alignment_enum: 1)
end

def render_debug args
  if !args.state.grid_rendered
    (NOKIA_HEIGHT + 1).map_with_index do |i|
      args.outputs.static_debug << {
        x:  NOKIA_X_OFFSET,
        y:  NOKIA_Y_OFFSET + (i * NOKIA_ZOOM),
        x2: NOKIA_X_OFFSET + NOKIA_ZOOMED_WIDTH,
        y2: NOKIA_Y_OFFSET + (i * NOKIA_ZOOM),
        r: 128,
        g: 128,
        b: 128,
        a: 80
      }.line
    end

    (NOKIA_WIDTH + 1).map_with_index do |i|
      args.outputs.static_debug << {
        x:  NOKIA_X_OFFSET + (i * NOKIA_ZOOM),
        y:  NOKIA_Y_OFFSET,
        x2: NOKIA_X_OFFSET + (i * NOKIA_ZOOM),
        y2: NOKIA_Y_OFFSET + NOKIA_ZOOMED_HEIGHT,
        r: 128,
        g: 128,
        b: 128,
        a: 80
      }.line
    end
  end

  args.state.grid_rendered = true

  args.state.last_click ||= 0
  args.state.last_up    ||= 0
  args.state.last_click   = Kernel.tick_count if args.nokia.mouse_down # you can also use args.nokia.click
  args.state.last_up      = Kernel.tick_count if args.nokia.mouse_up
  args.state.label_style  = { size_enum: -1.5 }

  args.state.watch_list = [
    "Kernel.tick_count is:          #{Kernel.tick_count}",
    "args.nokia.mouse_position is:  #{args.nokia.mouse_position.x}, #{args.nokia.mouse_position.y}",
    "args.nokia.mouse_down tick:    #{args.state.last_click || "never"}",
    "args.nokia.mouse_up tick:      #{args.state.last_up || "false"}",
  ]

  args.outputs.debug << args.state
                            .watch_list
                            .map_with_index do |text, i|
    {
      x: 5,
      y: 720 - (i * 18),
      text: text,
      size_enum: -1.5,
      r: 255, g: 255, b: 255
    }.label!
  end

  args.outputs.debug << {
    x: 640,
    y:  25,
    text: "INFO: dev mode is currently enabled. Comment out the invocation of ~render_debug~ within the ~tick~ method to hide the debug layer.",
    size_enum: -0.5,
    alignment_enum: 1,
    r: 255, g: 255, b: 255
  }.label!
end

def snake_demo args

end

$gtk.reset

Nokia 3310 - nokia.rb link

# ./samples/99_genre_lowrez/nokia_3310/app/nokia.rb
# Emulation of a 64x64 canvas. Don't change this file unless you know what you're doing :-)
# Head over to main.rb and study the code there.

NOKIA_WIDTH           = 84
NOKIA_HEIGHT          = 48
NOKIA_ZOOM            = 12
NOKIA_ZOOMED_WIDTH    = NOKIA_WIDTH  * NOKIA_ZOOM
NOKIA_ZOOMED_HEIGHT   = NOKIA_HEIGHT * NOKIA_ZOOM
NOKIA_X_OFFSET        = (1280 - NOKIA_ZOOMED_WIDTH).half
NOKIA_Y_OFFSET        = ( 720 - NOKIA_ZOOMED_HEIGHT).half

NOKIA_FONT_XL         = -1
NOKIA_FONT_XL_HEIGHT  = 20

NOKIA_FONT_LG         = -3.5
NOKIA_FONT_LG_HEIGHT  = 15

NOKIA_FONT_MD         = -6
NOKIA_FONT_MD_HEIGHT  = 10

NOKIA_FONT_SM         = -8.5
NOKIA_FONT_SM_HEIGHT  = 5

NOKIA_FONT_PATH       = 'fonts/lowrez.ttf'


class NokiaOutputs
  attr_accessor :width, :height

  def initialize args
    @args = args
  end

  def outputs_nokia
    return @args.outputs if Kernel.tick_count <= 0
    return @args.outputs[:nokia].transient!
  end

  def solids
    outputs_nokia.solids
  end

  def borders
    outputs_nokia.borders
  end

  def sprites
    outputs_nokia.sprites
  end

  def labels
    outputs_nokia.labels
  end

  def default_label
    {
      x: 0,
      y: 63,
      text: "",
      size_enum: NOKIA_FONT_SM,
      alignment_enum: 0,
      r: 0,
      g: 0,
      b: 0,
      a: 255,
      font: NOKIA_FONT_PATH
    }
  end

  def lines
    outputs_nokia.lines
  end

  def primitives
    outputs_nokia.primitives
  end

  def click
    return nil unless @args.inputs.mouse.click
    mouse
  end

  def mouse_click
    click
  end

  def mouse_down
    @args.inputs.mouse.down
  end

  def mouse_up
    @args.inputs.mouse.up
  end

  def mouse
    [
      ((@args.inputs.mouse.x - NOKIA_X_OFFSET).idiv(NOKIA_ZOOM)),
      ((@args.inputs.mouse.y - NOKIA_Y_OFFSET).idiv(NOKIA_ZOOM))
    ]
  end

  def mouse_position
    mouse
  end

  def keyboard
    @args.inputs.keyboard
  end
end

class GTK::Args
  def init_nokia
    return if @nokia
    @nokia = NokiaOutputs.new self
  end

  def nokia
    @nokia
  end
end

module GTK
  class Runtime
    alias_method :__original_tick_core__, :tick_core unless Runtime.instance_methods.include?(:__original_tick_core__)

    def tick_core
      @args.init_nokia

      __original_tick_core__

      return if Kernel.tick_count <= 0

      @args.render_target(:nokia)
           .labels
           .each do |l|
        l.y  += 1
        if (l.a || 255) > 128
          l.r = 67
          l.g = 82
          l.b = 61
          l.a = 255
        else
          l.a = 0
        end
      end

      @args.render_target(:nokia)
           .sprites
           .each do |s|
        if (s.a || 255) > 128
          s.a = 255
        else
          s.a = 0
        end
      end

      @args.render_target(:nokia)
           .solids
           .each do |s|
        if (s.a || 255) > 128
          s.r = 67
          s.g = 82
          s.b = 61
          s.a = 255
        else
          s.a = 0
        end
      end

      @args.render_target(:nokia)
           .borders
           .each do |s|
        if (s.a || 255) > 128
          s.r = 67
          s.g = 82
          s.b = 61
          s.a = 255
        else
          s.a = 0
        end
      end

      @args.render_target(:nokia)
           .lines
           .each do |l|
        l.y  += 1
        l.y2 += 1
        l.y2 += 1 if l.y != l.y2
        l.x2 += 1 if l.x != l.x2

        if (l.a || 255) > 128
          l.r = 67
          l.g = 82
          l.b = 61
          l.a = 255
        else
          l.a = 0
        end
      end

      @args.outputs.borders << {
        x: NOKIA_X_OFFSET      - 1,
        y: NOKIA_Y_OFFSET      - 1,
        w: NOKIA_ZOOMED_WIDTH  + 2,
        h: NOKIA_ZOOMED_HEIGHT + 2,
        r: 128, g: 128, b: 128
      }


      @args.outputs.background_color = [199, 240, 216]

      @args.outputs.solids << [0, 0, NOKIA_X_OFFSET, 720]
      @args.outputs.solids << [0, 0, 1280, NOKIA_Y_OFFSET]
      @args.outputs.solids << [NOKIA_X_OFFSET + NOKIA_ZOOMED_WIDTH, 0, NOKIA_X_OFFSET, 720]
      @args.outputs.solids << [0, NOKIA_Y_OFFSET.from_top, 1280, NOKIA_Y_OFFSET]

      @args.outputs
           .sprites << { x: NOKIA_X_OFFSET,
                         y: NOKIA_Y_OFFSET,
                         w: NOKIA_ZOOMED_WIDTH,
                         h: NOKIA_ZOOMED_HEIGHT,
                         source_x: 0,
                         source_y: 0,
                         source_w: NOKIA_WIDTH,
                         source_h: NOKIA_HEIGHT,
                         path: :nokia }

      if [email protected]_rendered
        (NOKIA_HEIGHT + 1).map_with_index do |i|
          @args.outputs.static_lines << {
            x:  NOKIA_X_OFFSET,
            y:  NOKIA_Y_OFFSET + (i * NOKIA_ZOOM),
            x2: NOKIA_X_OFFSET + NOKIA_ZOOMED_WIDTH,
            y2: NOKIA_Y_OFFSET + (i * NOKIA_ZOOM),
            r: 199,
            g: 240,
            b: 216,
            a: 100
          }.line!
        end

        (NOKIA_WIDTH + 1).map_with_index do |i|
          @args.outputs.static_lines << {
            x:  NOKIA_X_OFFSET + (i * NOKIA_ZOOM),
            y:  NOKIA_Y_OFFSET,
            x2: NOKIA_X_OFFSET + (i * NOKIA_ZOOM),
            y2: NOKIA_Y_OFFSET + NOKIA_ZOOMED_HEIGHT,
            r: 199,
            g: 240,
            b: 216,
            a: 100
          }.line!
        end

        @args.state.overlay_rendered = true
      end
    end
  end
end

Resolution 64x64 - lowrez.rb link

# ./samples/99_genre_lowrez/resolution_64x64/app/lowrez.rb
# Emulation of a 64x64 canvas. Don't change this file unless you know what you're doing :-)
# Head over to main.rb and study the code there.

LOWREZ_SIZE            = 64
LOWREZ_ZOOM            = 10
LOWREZ_ZOOMED_SIZE     = LOWREZ_SIZE * LOWREZ_ZOOM
LOWREZ_X_OFFSET        = (1280 - LOWREZ_ZOOMED_SIZE).half
LOWREZ_Y_OFFSET        = ( 720 - LOWREZ_ZOOMED_SIZE).half

LOWREZ_FONT_XL         = -1
LOWREZ_FONT_XL_HEIGHT  = 20

LOWREZ_FONT_LG         = -3.5
LOWREZ_FONT_LG_HEIGHT  = 15

LOWREZ_FONT_MD         = -6
LOWREZ_FONT_MD_HEIGHT  = 10

LOWREZ_FONT_SM         = -8.5
LOWREZ_FONT_SM_HEIGHT  = 5

LOWREZ_FONT_PATH       = 'fonts/lowrez.ttf'


class LowrezOutputs
  attr_accessor :width, :height

  def initialize args
    @args = args
    @background_color ||= [0, 0, 0]
    @args.outputs.background_color = @background_color
  end

  def background_color
    @background_color ||= [0, 0, 0]
  end

  def background_color= opts
    @background_color = opts
    @args.outputs.background_color = @background_color

    outputs_lowrez.solids << [0, 0, LOWREZ_SIZE, LOWREZ_SIZE, @background_color]
  end

  def outputs_lowrez
    return @args.outputs if Kernel.tick_count <= 0
    return @args.outputs[:lowrez]
  end

  def solids
    outputs_lowrez.solids
  end

  def borders
    outputs_lowrez.borders
  end

  def sprites
    outputs_lowrez.sprites
  end

  def labels
    outputs_lowrez.labels
  end

  def default_label
    {
      x: 0,
      y: 63,
      text: "",
      size_enum: LOWREZ_FONT_SM,
      alignment_enum: 0,
      r: 0,
      g: 0,
      b: 0,
      a: 255,
      font: LOWREZ_FONT_PATH
    }
  end

  def lines
    outputs_lowrez.lines
  end

  def primitives
    outputs_lowrez.primitives
  end

  def click
    return nil unless @args.inputs.mouse.click
    mouse
  end

  def mouse_click
    click
  end

  def mouse_down
    @args.inputs.mouse.down
  end

  def mouse_up
    @args.inputs.mouse.up
  end

  def mouse
    [
      ((@args.inputs.mouse.x - LOWREZ_X_OFFSET).idiv(LOWREZ_ZOOM)),
      ((@args.inputs.mouse.y - LOWREZ_Y_OFFSET).idiv(LOWREZ_ZOOM))
    ]
  end

  def mouse_position
    mouse
  end

  def keyboard
    @args.inputs.keyboard
  end
end

class GTK::Args
  def init_lowrez
    return if @lowrez
    @lowrez = LowrezOutputs.new self
  end

  def lowrez
    @lowrez
  end
end

module GTK
  class Runtime
    alias_method :__original_tick_core__, :tick_core unless Runtime.instance_methods.include?(:__original_tick_core__)

    def tick_core
      @args.init_lowrez
      __original_tick_core__

      return if Kernel.tick_count <= 0

      @args.render_target(:lowrez)
           .labels
           .each do |l|
        l.y  += 1
      end

      @args.render_target(:lowrez)
           .lines
           .each do |l|
        l.y  += 1
        l.y2 += 1
        l.y2 += 1 if l.y != l.y2
        l.x2 += 1 if l.x != l.x2
      end

      @args.outputs
           .sprites << { x: 320,
                         y: 40,
                         w: 640,
                         h: 640,
                         source_x: 0,
                         source_y: 0,
                         source_w: 64,
                         source_h: 64,
                         path: :lowrez }
    end
  end
end

Resolution 64x64 - main.rb link

# ./samples/99_genre_lowrez/resolution_64x64/app/main.rb
require 'app/lowrez.rb'

def tick args
  # How to set the background color
  args.lowrez.background_color = [255, 255, 255]

  # ==== HELLO WORLD ======================================================
  # Steps to get started:
  # 1. ~def tick args~ is the entry point for your game.
  # 2. There are quite a few code samples below, remove the "##"
  #    before each line and save the file to see the changes.
  # 3. 0,  0 is in bottom left and 63, 63 is in top right corner.
  # 4. Be sure to come to the discord channel if you need
  #    more help: [[http://discord.dragonruby.org]].

  # Commenting and uncommenting code:
  # - Add a "#" infront of lines to comment out code
  # - Remove the "#" infront of lines to comment out code

  # Invoke the hello_world subroutine/method
  hello_world args # <---- add a "#" to the beginning of the line to stop running this subroutine/method.
  # =======================================================================


  # ==== HOW TO RENDER A LABEL ============================================
  # Uncomment the line below to invoke the how_to_render_a_label subroutine/method.
  # Note: The method is defined in this file with the signature ~def how_to_render_a_label args~
  #       Scroll down to the method to see the details.

  # Remove the "#" at the beginning of the line below
  # how_to_render_a_label args # <---- remove the "#" at the begging of this line to run the method
  # =======================================================================


  # ==== HOW TO RENDER A FILLED SQUARE (SOLID) ============================
  # Remove the "#" at the beginning of the line below
  # how_to_render_solids args
  # =======================================================================


  # ==== HOW TO RENDER AN UNFILLED SQUARE (BORDER) ========================
  # Remove the "#" at the beginning of the line below
  # how_to_render_borders args
  # =======================================================================


  # ==== HOW TO RENDER A LINE =============================================
  # Remove the "#" at the beginning of the line below
  # how_to_render_lines args
  # =======================================================================


  # == HOW TO RENDER A SPRITE =============================================
  # Remove the "#" at the beginning of the line below
  # how_to_render_sprites args
  # =======================================================================


  # ==== HOW TO MOVE A SPRITE BASED OFF OF USER INPUT =====================
  # Remove the "#" at the beginning of the line below
  # how_to_move_a_sprite args
  # =======================================================================


  # ==== HOW TO ANIMATE A SPRITE (SEPERATE PNGS) ==========================
  # Remove the "#" at the beginning of the line below
  # how_to_animate_a_sprite args
  # =======================================================================


  # ==== HOW TO ANIMATE A SPRITE (SPRITE SHEET) ===========================
  # Remove the "#" at the beginning of the line below
  # how_to_animate_a_sprite_sheet args
  # =======================================================================


  # ==== HOW TO DETERMINE COLLISION =============================================
  # Remove the "#" at the beginning of the line below
  # how_to_determine_collision args
  # =======================================================================


  # ==== HOW TO CREATE BUTTONS ==================================================
  # Remove the "#" at the beginning of the line below
  # how_to_create_buttons args
  # =======================================================================


  # ==== The line below renders a debug grid, mouse information, and current tick
  render_debug args
end

def hello_world args
  args.lowrez.solids  << { x: 0, y: 64, w: 10, h: 10, r: 255 }

  args.lowrez.labels  << {
    x: 32,
    y: 63,
    text: "lowrezjam 2020",
    size_enum: LOWREZ_FONT_SM,
    alignment_enum: 1,
    r: 0,
    g: 0,
    b: 0,
    a: 255,
    font: LOWREZ_FONT_PATH
  }

  args.lowrez.sprites << {
    x: 32 - 10,
    y: 32 - 10,
    w: 20,
    h: 20,
    path: 'sprites/lowrez-ship-blue.png',
    a: Kernel.tick_count % 255,
    angle: Kernel.tick_count % 360
  }
end


# =======================================================================
# ==== HOW TO RENDER A LABEL ============================================
# =======================================================================
def how_to_render_a_label args
  # NOTE: Text is aligned from the TOP LEFT corner

  # Render an EXTRA LARGE/XL label (remove the "#" in front of each line below)
  args.lowrez.labels << { x: 0, y: 57, text: "Hello World",
                         size_enum: LOWREZ_FONT_XL,
                         r: 0, g: 0, b: 0, a: 255,
                         font: LOWREZ_FONT_PATH }

  # Render a LARGE/LG label (remove the "#" in front of each line below)
  args.lowrez.labels << { x: 0, y: 36, text: "Hello World",
                          size_enum: LOWREZ_FONT_LG,
                          r: 0, g: 0, b: 0, a: 255,
                          font: LOWREZ_FONT_PATH }

  # Render a MEDIUM/MD label (remove the "#" in front of each line below)
  args.lowrez.labels << { x: 0, y: 20, text: "Hello World",
                          size_enum: LOWREZ_FONT_MD,
                          r: 0, g: 0, b: 0, a: 255,
                          font: LOWREZ_FONT_PATH }

  # Render a SMALL/SM label (remove the "#" in front of each line below)
  args.lowrez.labels << { x: 0, y: 9, text: "Hello World",
                          size_enum: LOWREZ_FONT_SM,
                          r: 0, g: 0, b: 0, a: 255,
                          font: LOWREZ_FONT_PATH }

  # You are provided args.lowrez.default_label which returns a Hash that you
  # can ~merge~ properties with
  # Example 1
  args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(text: "Default")

  # Example 2
  args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(x: 31,
                                   text: "Default",
                                   r: 128,
                                   g: 128,
                                   b: 128)
end

## # =============================================================================
## # ==== HOW TO RENDER FILLED SQUARES (SOLIDS) ==================================
## # =============================================================================
def how_to_render_solids args
  # Render a red square at 0, 0 with a width and height of 1
  args.lowrez.solids << { x: 0, y: 0, w: 1, h: 1, r: 255, g: 0, b: 0, a: 255 }

  # Render a red square at 1, 1 with a width and height of 2
  args.lowrez.solids << { x: 1, y: 1, w: 2, h: 2, r: 255, g: 0, b: 0, a: 255 }

  # Render a red square at 3, 3 with a width and height of 3
  args.lowrez.solids << { x: 3, y: 3, w: 3, h: 3, r: 255, g: 0, b: 0 }

  # Render a red square at 6, 6 with a width and height of 4
  args.lowrez.solids << { x: 6, y: 6, w: 4, h: 4, r: 255, g: 0, b: 0 }
end

## # =============================================================================
## # ==== HOW TO RENDER UNFILLED SQUARES (BORDERS) ===============================
## # =============================================================================
def how_to_render_borders args
  # Render a red square at 0, 0 with a width and height of 3
  args.lowrez.borders << { x: 0, y: 0, w: 3, h: 3, r: 255, g: 0, b: 0, a: 255 }

  # Render a red square at 3, 3 with a width and height of 3
  args.lowrez.borders << { x: 3, y: 3, w: 4, h: 4, r: 255, g: 0, b: 0, a: 255 }

  # Render a red square at 5, 5 with a width and height of 4
  args.lowrez.borders << { x: 7, y: 7, w: 5, h: 5, r: 255, g: 0, b: 0, a: 255 }
end

## # =============================================================================
## # ==== HOW TO RENDER A LINE ===================================================
## # =============================================================================
def how_to_render_lines args
  # Render a horizontal line at the bottom
  args.lowrez.lines << { x: 0, y: 0, x2: 63, y2:  0, r: 255 }

  # Render a vertical line at the left
  args.lowrez.lines << { x: 0, y: 0, x2:  0, y2: 63, r: 255 }

  # Render a diagonal line starting from the bottom left and going to the top right
  args.lowrez.lines << { x: 0, y: 0, x2: 63, y2: 63, r: 255 }
end

## # =============================================================================
## # == HOW TO RENDER A SPRITE ===================================================
## # =============================================================================
def how_to_render_sprites args
  # Loop 10 times and create 10 sprites in 10 positions
  # Render a sprite at the bottom left with a width and height of 5 and a path of 'sprites/lowrez-ship-blue.png'
  10.times do |i|
    args.lowrez.sprites << {
      x: i * 5,
      y: i * 5,
      w: 5,
      h: 5,
      path: 'sprites/lowrez-ship-blue.png'
    }
  end

  # Given an array of positions create sprites
  positions = [
    { x: 10, y: 42 },
    { x: 15, y: 45 },
    { x: 22, y: 33 },
  ]

  positions.each do |position|
    # use Ruby's ~Hash#merge~ function to create a sprite
    args.lowrez.sprites << position.merge(path: 'sprites/lowrez-ship-red.png',
                                          w: 5,
                                          h: 5)
  end
end

## # =============================================================================
## # ==== HOW TO ANIMATE A SPRITE (SEPERATE PNGS) ==========================
## # =============================================================================
def how_to_animate_a_sprite args
  # STEP 1: Define when you want the animation to start. The animation in this case will start in 3 seconds
  start_animation_on_tick = 180

  # STEP 2: Get the frame_index given the start tick.
  sprite_index = start_animation_on_tick.frame_index count: 7,     # how many sprites?
                                                     hold_for: 4,  # how long to hold each sprite?
                                                     repeat: true  # should it repeat?

  # STEP 3: frame_index will return nil if the frame hasn't arrived yet
  if sprite_index
    # if the sprite_index is populated, use it to determine the sprite path and render it
    sprite_path  = "sprites/explosion-#{sprite_index}.png"
    args.lowrez.sprites << { x: 0, y: 0, w: 64, h: 64, path: sprite_path }
  else
    # if the sprite_index is nil, render a countdown instead
    countdown_in_seconds = ((start_animation_on_tick - Kernel.tick_count) / 60).round(1)

    args.lowrez.labels  << args.lowrez
                               .default_label
                               .merge(x: 32,
                                      y: 32,
                                      text: "Count Down: #{countdown_in_seconds}",
                                      alignment_enum: 1)
  end

  # render the current tick and the resolved sprite index
  args.lowrez.labels  << args.lowrez
                               .default_label
                               .merge(x: 0,
                                      y: 11,
                                      text: "Tick: #{Kernel.tick_count}")
  args.lowrez.labels  << args.lowrez
                               .default_label
                               .merge(x: 0,
                                      y: 5,
                                      text: "sprite_index: #{sprite_index}")
end

## # =============================================================================
## # ==== HOW TO ANIMATE A SPRITE (SPRITE SHEET) =================================
## # =============================================================================
def how_to_animate_a_sprite_sheet args
  # STEP 1: Define when you want the animation to start. The animation in this case will start in 3 seconds
  start_animation_on_tick = 180

  # STEP 2: Get the frame_index given the start tick.
  sprite_index = start_animation_on_tick.frame_index count: 7,     # how many sprites?
                                                     hold_for: 4,  # how long to hold each sprite?
                                                     repeat: true  # should it repeat?

  # STEP 3: frame_index will return nil if the frame hasn't arrived yet
  if sprite_index
    # if the sprite_index is populated, use it to determine the source rectangle and render it
    args.lowrez.sprites << {
      x: 0,
      y: 0,
      w: 64,
      h: 64,
      path:  "sprites/explosion-sheet.png",
      source_x: 32 * sprite_index,
      source_y: 0,
      source_w: 32,
      source_h: 32
    }
  else
    # if the sprite_index is nil, render a countdown instead
    countdown_in_seconds = ((start_animation_on_tick - Kernel.tick_count) / 60).round(1)

    args.lowrez.labels  << args.lowrez
                               .default_label
                               .merge(x: 32,
                                      y: 32,
                                      text: "Count Down: #{countdown_in_seconds}",
                                      alignment_enum: 1)
  end

  # render the current tick and the resolved sprite index
  args.lowrez.labels  << args.lowrez
                               .default_label
                               .merge(x: 0,
                                      y: 11,
                                      text: "tick: #{Kernel.tick_count}")
  args.lowrez.labels  << args.lowrez
                               .default_label
                               .merge(x: 0,
                                      y: 5,
                                      text: "sprite_index: #{sprite_index}")
end

## # =============================================================================
## # ==== HOW TO STORE STATE, ACCEPT INPUT, AND RENDER SPRITE BASED OFF OF STATE =
## # =============================================================================
def how_to_move_a_sprite args
  args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(x: 32,
                                   y: 62, text: "Use Arrow Keys",
                                   alignment_enum: 1)

  args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(x: 32,
                                   y: 56, text: "Use WASD",
                                   alignment_enum: 1)

  args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(x: 32,
                                   y: 50, text: "Or Click",
                                   alignment_enum: 1)

  # set the initial values for x and y using ||= ("or equal operator")
  args.state.ship.x ||= 0
  args.state.ship.y ||= 0

  # if a mouse click occurs, update the ship's x and y to be the location of the click
  if args.lowrez.mouse_click
    args.state.ship.x = args.lowrez.mouse_click.x
    args.state.ship.y = args.lowrez.mouse_click.y
  end

  # if a or left arrow is pressed/held, decrement the ships x position
  if args.lowrez.keyboard.left
    args.state.ship.x -= 1
  end

  # if d or right arrow is pressed/held, increment the ships x position
  if args.lowrez.keyboard.right
    args.state.ship.x += 1
  end

  # if s or down arrow is pressed/held, decrement the ships y position
  if args.lowrez.keyboard.down
    args.state.ship.y -= 1
  end

  # if w or up arrow is pressed/held, increment the ships y position
  if args.lowrez.keyboard.up
    args.state.ship.y += 1
  end

  # render the sprite to the screen using the position stored in args.state.ship
  args.lowrez.sprites << {
    x: args.state.ship.x,
    y: args.state.ship.y,
    w: 5,
    h: 5,
    path: 'sprites/lowrez-ship-blue.png',
    # parameters beyond this point are optional
    angle: 0, # Note: rotation angle is denoted in degrees NOT radians
    r: 255,
    g: 255,
    b: 255,
    a: 255
  }
end

# =======================================================================
# ==== HOW TO DETERMINE COLLISION =======================================
# =======================================================================
def how_to_determine_collision args
  # Render the instructions
  args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(x: 32,
                                   y: 62, text: "Click Anywhere",
                                   alignment_enum: 1)

  # if a mouse click occurs:
  # - set ship_one if it isn't set
  # - set ship_two if it isn't set
  # - otherwise reset ship one and ship two
  if args.lowrez.mouse_click
    # is ship_one set?
    if !args.state.ship_one
      args.state.ship_one = { x: args.lowrez.mouse_click.x - 10,
                              y: args.lowrez.mouse_click.y - 10,
                              w: 20,
                              h: 20 }
    # is ship_one set?
    elsif !args.state.ship_two
      args.state.ship_two = { x: args.lowrez.mouse_click.x - 10,
                              y: args.lowrez.mouse_click.y - 10,
                              w: 20,
                              h: 20 }
    # should we reset?
    else
      args.state.ship_one = nil
      args.state.ship_two = nil
    end
  end

  # render ship one if it's set
  if args.state.ship_one
    # use Ruby's .merge method which is available on ~Hash~ to set the sprite and alpha
    # render ship one
    args.lowrez.sprites << args.state.ship_one.merge(path: 'sprites/lowrez-ship-blue.png', a: 100)
  end

  if args.state.ship_two
    # use Ruby's .merge method which is available on ~Hash~ to set the sprite and alpha
    # render ship two
    args.lowrez.sprites << args.state.ship_two.merge(path: 'sprites/lowrez-ship-red.png', a: 100)
  end

  # if both ship one and ship two are set, then determine collision
  if args.state.ship_one && args.state.ship_two
    # collision is determined using the intersect_rect? method
    if args.state.ship_one.intersect_rect? args.state.ship_two
      # if collision occurred, render the words collision!
      args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(x: 31,
                                   y: 5,
                                   text: "Collision!",
                                   alignment_enum: 1)
    else
      # if collision occurred, render the words no collision.
      args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(x: 31,
                                   y: 5,
                                   text: "No Collision.",
                                   alignment_enum: 1)
    end
  else
    # if both ship one and ship two aren't set, then render --
      args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(x: 31,
                                   y: 6,
                                   text: "--",
                                   alignment_enum: 1)
  end
end

## # =============================================================================
## # ==== HOW TO CREATE BUTTONS ==================================================
## # =============================================================================
def how_to_create_buttons args
  # Define a button style
  args.state.button_style = { w: 62, h: 10, r: 80, g: 80, b: 80 }
  args.state.label_style  = { r: 80, g: 80, b: 80 }

  # Render instructions
  args.state.button_message ||= "Press a Button!"
  args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(args.state.label_style)
                            .merge(x: 32,
                                   y: 62,
                                   text: args.state.button_message,
                                   alignment_enum: 1)


  # Creates button one using a border and a label
  args.state.button_one_border = args.state.button_style.merge( x: 1, y: 32)
  args.lowrez.borders << args.state.button_one_border
  args.lowrez.labels  << args.lowrez
                             .default_label
                             .merge(args.state.label_style)
                             .merge(x: args.state.button_one_border.x + 2,
                                    y: args.state.button_one_border.y + LOWREZ_FONT_SM_HEIGHT + 2,
                                    text: "Button One")

  # Creates button two using a border and a label
  args.state.button_two_border = args.state.button_style.merge( x: 1, y: 20)

  args.lowrez.borders << args.state.button_two_border
  args.lowrez.labels << args.lowrez
                            .default_label
                            .merge(args.state.label_style)
                            .merge(x: args.state.button_two_border.x + 2,
                                   y: args.state.button_two_border.y + LOWREZ_FONT_SM_HEIGHT + 2,
                                   text: "Button Two")

  # Initialize the state variable that tracks which button was clicked to "" (empty stringI
  args.state.last_button_clicked ||= "--"

  # If a click occurs, check to see if either button one, or button two was clicked
  # using the inside_rect? method of the mouse
  # set args.state.last_button_clicked accordingly
  if args.lowrez.mouse_click
    if args.lowrez.mouse_click.inside_rect? args.state.button_one_border
      args.state.last_button_clicked = "One Clicked!"
    elsif args.lowrez.mouse_click.inside_rect? args.state.button_two_border
      args.state.last_button_clicked = "Two Clicked!"
    else
      args.state.last_button_clicked = "--"
    end
  end

  # Render the current value of args.state.last_button_clicked
  args.lowrez.labels << args.lowrez
                             .default_label
                             .merge(args.state.label_style)
                             .merge(x: 32,
                                    y: 5,
                                    text: args.state.last_button_clicked,
                                    alignment_enum: 1)
end


def render_debug args
  if !args.state.grid_rendered
    65.map_with_index do |i|
      args.outputs.static_debug << {
        x:  LOWREZ_X_OFFSET,
        y:  LOWREZ_Y_OFFSET + (i * 10),
        x2: LOWREZ_X_OFFSET + LOWREZ_ZOOMED_SIZE,
        y2: LOWREZ_Y_OFFSET + (i * 10),
        r: 128,
        g: 128,
        b: 128,
        a: 80
      }.line!

      args.outputs.static_debug << {
        x:  LOWREZ_X_OFFSET + (i * 10),
        y:  LOWREZ_Y_OFFSET,
        x2: LOWREZ_X_OFFSET + (i * 10),
        y2: LOWREZ_Y_OFFSET + LOWREZ_ZOOMED_SIZE,
        r: 128,
        g: 128,
        b: 128,
        a: 80
      }.line!
    end
  end

  args.state.grid_rendered = true

  args.state.last_click ||= 0
  args.state.last_up    ||= 0
  args.state.last_click   = Kernel.tick_count if args.lowrez.mouse_down # you can also use args.lowrez.click
  args.state.last_up      = Kernel.tick_count if args.lowrez.mouse_up
  args.state.label_style  = { size_enum: -1.5 }

  args.state.watch_list = [
    "Kernel.tick_count is:           #{Kernel.tick_count}",
    "args.lowrez.mouse_position is:  #{args.lowrez.mouse_position.x}, #{args.lowrez.mouse_position.y}",
    "args.lowrez.mouse_down tick:    #{args.state.last_click || "never"}",
    "args.lowrez.mouse_up tick:      #{args.state.last_up || "false"}",
  ]

  args.outputs.debug << args.state
                            .watch_list
                            .map_with_index do |text, i|
    {
      x: 5,
      y: 720 - (i * 20),
      text: text,
      size_enum: -1.5
    }.label!
  end

  args.outputs.debug << {
    x: 640,
    y:  25,
    text: "INFO: dev mode is currently enabled. Comment out the invocation of ~render_debug~ within the ~tick~ method to hide the debug layer.",
    size_enum: -0.5,
    alignment_enum: 1
  }.label!
end

$gtk.reset

Genre Mario link

Jumping - main.rb link

# ./samples/99_genre_mario/01_jumping/app/main.rb
def tick args
  defaults args
  input args
  calc args
  render args
end

def defaults args
  args.state.player ||= {
    x: Grid.w / 2,
    y: 0,
    w: 100,
    h: 100,
    dy: 0,
    action: :standing
  }

  args.state.jump ||= {
    power: 20,
    increase_frames: 10,
    increase_power: 1
  }

  args.state.gravity ||= -1
end

def input args
  if args.inputs.keyboard.key_down.space
    if args.state.player.action == :standing
      args.state.player.action = :jumping
      args.state.player.dy = args.state.jump.power

      # record when the action took place
      current_frame = Kernel.tick_count
      args.state.player.action_at = current_frame
    end
  end

  # if the space bar is being held
  if args.inputs.keyboard.key_held.space
    # is the player jumping
    is_jumping = args.state.player.action == :jumping

    # when was the jump performed
    time_of_jump = args.state.player.action_at

    # how much time has passed since the jump
    jump_elapsed_time = time_of_jump.elapsed_time

    # how much time is allowed for increasing power
    time_allowed = args.state.jump.increase_frames

    # if the player is jumping
    # and the elapsed time is less than
    # the allowed time
    if is_jumping && jump_elapsed_time < time_allowed
       # increase the dy by the increase power
       power_to_add = args.state.jump.increase_power
       args.state.player.dy += power_to_add
    end
  end
end

def calc args
  if args.state.player.action == :jumping
    args.state.player.y  += args.state.player.dy
    args.state.player.dy += args.state.gravity
  end

  if args.state.player.y < 0
    args.state.player.y      = 0
    args.state.player.action = :standing
  end
end

def render args
  args.outputs.sprites << {
    x: args.state.player.x -
       args.state.player.w / 2,
    y: args.state.player.y,
    w: args.state.player.w,
    h: args.state.player.h,
    path: 'sprites/square/red.png'
  }
end

Jumping And Collisions - main.rb link

# ./samples/99_genre_mario/02_jumping_and_collisions/app/main.rb
class Game
  attr_gtk

  def tick
    defaults
    input
    calc
    render
  end

  def defaults
    state.gravity              ||= -1

    player.x                   ||= 64
    player.y                   ||= 800
    player.w                   ||= 50
    player.h                   ||= 50
    player.dx                  ||= 0
    player.dy                  ||= 0
    player.on_ground           ||= false

    player.max_speed           ||= 20
    player.jump_power          ||= 15
    player.jump_air_time       ||= 15
    player.jump_increase_power ||= 1

    state.tile_size            ||= 64
    if !state.tiles
      state.tiles                = [
        { ordinal_x:  0, ordinal_y: 0 },
        { ordinal_x:  1, ordinal_y: 0 },
        { ordinal_x:  2, ordinal_y: 0 },
        { ordinal_x:  3, ordinal_y: 0 },
        { ordinal_x:  4, ordinal_y: 0 },
        { ordinal_x:  5, ordinal_y: 0 },
        { ordinal_x:  6, ordinal_y: 0 },
        { ordinal_x:  7, ordinal_y: 0 },
        { ordinal_x:  8, ordinal_y: 0 },
        { ordinal_x:  9, ordinal_y: 0 },
        { ordinal_x: 10, ordinal_y: 0 },
        { ordinal_x: 11, ordinal_y: 0 },
        { ordinal_x: 12, ordinal_y: 0 },
        { ordinal_x: 13, ordinal_y: 0 },

        { ordinal_x:  3, ordinal_y: 1 },
        { ordinal_x:  3, ordinal_y: 2 },
        { ordinal_x:  6, ordinal_y: 1 },
        { ordinal_x:  6, ordinal_y: 2 },

        { ordinal_x:  9, ordinal_y: 3 },
        { ordinal_x: 10, ordinal_y: 3 },
        { ordinal_x: 11, ordinal_y: 3 },

        { ordinal_x: 10, ordinal_y: 4 },
        { ordinal_x: 11, ordinal_y: 4 },

        { ordinal_x: 11, ordinal_y: 5 },

        { ordinal_x: 12, ordinal_y: 2 },
      ]

      state.tiles.each do |t|
        t.rect = { x: t.ordinal_x * state.tile_size,
                   y: t.ordinal_y * state.tile_size,
                   w: state.tile_size,
                   h: state.tile_size }
      end
    end
  end

  def input
    input_jump
    input_move
  end

  def input_jump
    if inputs.keyboard.key_down.space
      player_jump
    end

    if inputs.keyboard.key_held.space
      player_jump_increase_air_time
    end
  end

  def input_move
    if inputs.keyboard.left
      player.dx -= 2
    elsif inputs.keyboard.right
      player.dx += 2
    end
    player.dx = player.dx.clamp(-player.max_speed, player.max_speed)
  end

  def calc
    calc_physics
    calc_game_over
  end

  def calc_physics
    player.x  += player.dx
    collision = state.tiles.find { |t| player.intersect_rect? t.rect }
    if collision
      if player.dx > 0
        player.x = collision.rect.x - player.w
      elsif player.dx < 0
        player.x = collision.rect.x + collision.rect.w
      end
    end
    player.dx *= 0.8

    player.y += player.dy
    collision = state.tiles.find { |t| player.intersect_rect? t.rect }
    if collision
      if player.dy > 0
        player.y = collision.rect.y - player.h
      elsif player.dy < 0
        player.y = collision.rect.y + collision.rect.h
      end
      player.dy = 0
      player.jump_at = nil
      player.on_ground = true
    else
      player.on_ground = false
    end
    player.dy = player.dy + state.gravity
    player.dy = player.dy.clamp(-state.tile_size, state.tile_size)
  end

  def calc_game_over
    if player.y < -64
      player.y = 800
      player.dx = 0
      player.dy = 0
    end
  end

  def render
    render_player
    render_tiles
    # render_grid
  end

  def render_player
    outputs.sprites << {
      x: player.x,
      y: player.y,
      w: player.w,
      h: player.h,
      path: 'sprites/square/red.png'
    }
  end

  def render_tiles
    outputs.sprites << state.tiles.map do |t|
      t.merge path: 'sprites/square/white.png',
              x: t.ordinal_x * state.tile_size,
              y: t.ordinal_y * state.tile_size,
              w: state.tile_size,
              h: state.tile_size
    end
  end

  def render_grid
    if Kernel.tick_count == 0
      outputs[:grid].background_color = [0, 0, 0, 0]
      outputs[:grid].borders << available_brick_locations
      outputs[:grid].labels  << available_brick_locations.map do |b|
        [
          b.merge(text: "#{b.ordinal_x},#{b.ordinal_y}",
                  x: b.x + 2,
                  y: b.y + 2,
                  size_enum: -3,
                  vertical_alignment_enum: 0,
                  blendmode_enum: 0),
          b.merge(text: "#{b.x},#{b.y}",
                  x: b.x + 2,
                  y: b.y + 2 + 20,
                  size_enum: -3,
                  vertical_alignment_enum: 0,
                  blendmode_enum: 0)
        ]
      end
    end

    outputs.sprites << { x: 0, y: 0, w: 1280, h: 720, path: :grid }
  end

  def available_brick_locations
    (0..19).to_a
      .product(0..11)
      .map do |(ordinal_x, ordinal_y)|
      { ordinal_x: ordinal_x,
        ordinal_y: ordinal_y,
        x: ordinal_x * state.tile_size,
        y: ordinal_y * state.tile_size,
        w: state.tile_size,
        h: state.tile_size }
    end
  end

  def player
    state.player ||= args.state.new_entity :player
  end

  def player_jump
    return if !player.on_ground
    player.dy = state.player.jump_power
    player.jump_at = Kernel.tick_count
  end

  def player_jump_increase_air_time
    return if !player.jump_at
    return if player.jump_at.elapsed_time >= player.jump_air_time
    player.dy += player.jump_increase_power
  end
end

def tick args
  $game ||= Game.new
  $game.args = args
  $game.tick
end

$gtk.reset

Genre Platformer link

Clepto Frog - main.rb link

# ./samples/99_genre_platformer/clepto_frog/app/main.rb
class CleptoFrog
  attr_gtk

  def tick
    defaults
    render
    input
    calc
  end

  def defaults
    state.level_editor_rect_w ||= 32
    state.level_editor_rect_h     ||= 32
    state.target_camera_scale ||= 0.5
    state.camera_scale        ||= 1
    state.tongue_length       ||= 100
    state.action              ||= :aiming
    state.tongue_angle        ||= 90
    state.tile_size           ||= 32
    state.gravity             ||= -0.1
    state.drag                ||= -0.005
    state.player ||= {
      x: 2400,
      y: 200,
      w: 60,
      h: 60,
      dx: 0,
      dy: 0,
    }
    state.camera_x     ||= state.player.x - 640
    state.camera_y     ||= 0
    load_if_needed
    state.map_saved_at ||= 0
  end

  def player
    state.player
  end

  def render
    render_world
    render_player
    render_level_editor
    render_mini_map
    render_instructions
  end

  def to_camera_space rect
    rect.merge(x: to_camera_space_x(rect.x),
               y: to_camera_space_y(rect.y),
               w: to_camera_space_w(rect.w),
               h: to_camera_space_h(rect.h))
  end

  def to_camera_space_x x
    return nil if !x
     (x * state.camera_scale) - state.camera_x
  end

  def to_camera_space_y y
    return nil if !y
    (y * state.camera_scale) - state.camera_y
  end

  def to_camera_space_w w
    return nil if !w
    w * state.camera_scale
  end

  def to_camera_space_h h
    return nil if !h
    h * state.camera_scale
  end

  def render_world
    viewport = {
      x: player.x - 1280 / state.camera_scale,
      y: player.y - 720 / state.camera_scale,
      w: 2560 / state.camera_scale,
      h: 1440 / state.camera_scale
    }

    outputs.sprites << geometry.find_all_intersect_rect(viewport, state.mugs).map do |rect|
      to_camera_space rect
    end

    outputs.sprites << geometry.find_all_intersect_rect(viewport, state.walls).map do |rect|
      to_camera_space(rect).merge!(path: :pixel, r: 128, g: 128, b: 128, a: 128)
    end
  end

  def render_player
    start_of_tongue_render = to_camera_space start_of_tongue

    if state.anchor_point
      anchor_point_render = to_camera_space state.anchor_point
      outputs.sprites << { x: start_of_tongue_render.x - 2,
                           y: start_of_tongue_render.y - 2,
                           w: to_camera_space_w(4),
                           h: geometry.distance(start_of_tongue_render, anchor_point_render),
                           path:  :pixel,
                           angle_anchor_y: 0,
                           r: 255, g: 128, b: 128,
                           angle: state.tongue_angle - 90 }
    else
      outputs.sprites << { x: to_camera_space_x(start_of_tongue.x) - 2,
                           y: to_camera_space_y(start_of_tongue.y) - 2,
                           w: to_camera_space_w(4),
                           h: to_camera_space_h(state.tongue_length),
                           path:  :pixel,
                           r: 255, g: 128, b: 128,
                           angle_anchor_y: 0,
                           angle: state.tongue_angle - 90 }
    end

    angle = 0
    if state.action == :aiming && !player.on_floor
      angle = state.tongue_angle - 90
    elsif state.action == :shooting && !player.on_floor
      angle = state.tongue_angle - 90
    elsif state.action == :anchored
      angle = state.tongue_angle - 90
    end

    outputs.sprites << to_camera_space(player).merge!(path: "sprites/square/green.png", angle: angle)
  end

  def render_mini_map
    x, y = 1170, 10
    outputs.primitives << { x: x,
                            y: y,
                            w: 100,
                            h: 58,
                            r: 0,
                            g: 0,
                            b: 0,
                            a: 200,
                            path: :pixel }

    outputs.primitives << { x: x + player.x.fdiv(100) - 1,
                            y: y + player.y.fdiv(100) - 1,
                            w: 2,
                            h: 2,
                            r: 0,
                            g: 255,
                            b: 0,
                            path: :pixel }

    t_start = start_of_tongue
    t_end = end_of_tongue

    outputs.primitives << {
      x: x + t_start.x.fdiv(100),
      y: y + t_start.y.fdiv(100),
      x2: x + t_end.x.fdiv(100),
      y2: y + t_end.y.fdiv(100),
      r: 255, g: 255, b: 255
    }

    outputs.primitives << state.mugs.map do |o|
      { x: x + o.x.fdiv(100) - 1,
        y: y + o.y.fdiv(100) - 1,
        w: 2,
        h: 2,
        r: 200,
        g: 200,
        b: 0,
        path: :pixel }
    end
  end

  def render_level_editor
    return if !state.level_editor_mode
    if state.map_saved_at > 0 && state.map_saved_at.elapsed_time < 120
      outputs.primitives << { x: 920, y: 670, text: 'Map has been exported!', size_enum: 1, r: 0, g: 50, b: 100, a: 50 }
    end

    outputs.primitives << { x: to_camera_space_x(((state.camera_x + inputs.mouse.x) / state.camera_scale).ifloor(state.tile_size)),
                            y: to_camera_space_y(((state.camera_y + inputs.mouse.y) / state.camera_scale).ifloor(state.tile_size)),
                            w: to_camera_space_w(state.level_editor_rect_w),
                            h: to_camera_space_h(state.level_editor_rect_h), path: :pixel, a: 200, r: 180, g: 80, b: 200 }
  end

  def render_instructions
    if state.level_editor_mode
      outputs.labels << { x: 640,
                          y: 10.from_top,
                          text: "Click to place wall. HJKL to change wall size. X + click to remove wall. M + click to place mug. Arrow keys to move around.",
                          size_enum: -1,
                          anchor_x: 0.5 }
      outputs.labels << { x: 640,
                          y: 35.from_top,
                          text: " - and + to zoom in and out. 0 to reset camera to default zoom. G to exit level editor mode.",
                          size_enum: -1,
                          anchor_x: 0.5 }
    else
      outputs.labels << { x: 640,
                          y: 10.from_top,
                          text: "Left and Right to aim tongue. Space to shoot or release tongue. G to enter level editor mode.",
                          size_enum: -1,
                          anchor_x: 0.5 }

      outputs.labels << { x: 640,
                          y: 35.from_top,
                          text: "Up and Down to change tongue length (when tongue is attached). Left and Right to swing (when tongue is attached).",
                          size_enum: -1,
                          anchor_x: 0.5 }
    end
  end

  def start_of_tongue
    {
      x: player.x + player.w / 2,
      y: player.y + player.h / 2
    }
  end

  def calc
    calc_camera
    calc_player
    calc_mug_collection
  end

  def calc_camera
    percentage = 0.2 * state.camera_scale
    target_scale = state.target_camera_scale
    distance_scale = target_scale - state.camera_scale
    state.camera_scale += distance_scale * percentage

    target_x = player.x * state.target_camera_scale
    target_y = player.y * state.target_camera_scale

    distance_x = target_x - (state.camera_x + 640)
    distance_y = target_y - (state.camera_y + 360)
    state.camera_x += distance_x * percentage if distance_x.abs > 1
    state.camera_y += distance_y * percentage if distance_y.abs > 1
    state.camera_x = 0 if state.camera_x < 0
    state.camera_y = 0 if state.camera_y < 0
  end

  def calc_player
    calc_shooting
    calc_swing
    calc_aabb_collision
    calc_tongue_angle
    calc_on_floor
  end

  def calc_shooting
    calc_shooting_step
    calc_shooting_step
    calc_shooting_step
    calc_shooting_step
    calc_shooting_step
    calc_shooting_step
  end

  def calc_shooting_step
    return unless state.action == :shooting
    state.tongue_length += 5
    potential_anchor = end_of_tongue
    anchor_rect = { x: potential_anchor.x - 5, y: potential_anchor.y - 5, w: 10, h: 10 }
    collision = state.walls.find_all do |v|
      v.intersect_rect?(anchor_rect)
    end.first
    if collision
      state.anchor_point = potential_anchor
      state.action = :anchored
    end
  end

  def calc_swing
    return if !state.anchor_point
    target_x = state.anchor_point.x - start_of_tongue.x
    target_y = state.anchor_point.y -
               state.tongue_length - 5 - 20 - player.h

    diff_y = player.y - target_y

    distance = geometry.distance(player, state.anchor_point)
    pull_strength = if distance < 100
                      0
                    else
                      (distance / 800)
                    end

    vector = state.tongue_angle.to_vector

    player.dx += vector.x * pull_strength**2
    player.dy += vector.y * pull_strength**2
  end

  def calc_aabb_collision
    return if !state.walls

    player.dx = player.dx.clamp(-30, 30)
    player.dy = player.dy.clamp(-30, 30)

    player.dx += player.dx * state.drag
    player.x += player.dx

    collision = geometry.find_intersect_rect player, state.walls

    if collision
      if player.dx > 0
        player.x = collision.x - player.w
      elsif player.dx < 0
        player.x = collision.x + collision.w
      end
      player.dx *= -0.8
    end

    if !state.level_editor_mode
      player.dy += state.gravity  # Since acceleration is the change in velocity, the change in y (dy) increases every frame
      player.y += player.dy
    end

    collision = geometry.find_intersect_rect player, state.walls

    if collision
      if player.dy > 0
        player.y = collision.y - 60
      elsif player.dy < 0
        player.y = collision.y + collision.h
      end

      player.dy *= -0.8
    end
  end

  def calc_tongue_angle
    return unless state.anchor_point
    state.tongue_angle = geometry.angle_from state.anchor_point, start_of_tongue
    state.tongue_length = geometry.distance(start_of_tongue, state.anchor_point)
    state.tongue_length = state.tongue_length.greater(100)
  end

  def calc_on_floor
    if state.action == :anchored
      player.on_floor = false
      player.on_floor_debounce = 30
    else
      player.on_floor_debounce ||= 30

      if player.dy.round != 0
        player.on_floor_debounce = 30
        player.on_floor = false
      else
        player.on_floor_debounce -= 1
      end

      if player.on_floor_debounce <= 0
        player.on_floor_debounce = 0
        player.on_floor = true
      end
    end
  end

  def calc_mug_collection
    collected = state.mugs.find_all { |s| s.intersect_rect? player }
    state.mugs.reject! { |s| collected.include? s }
  end

  def set_camera_scale v = nil
    return if v < 0.1
    state.target_camera_scale = v
  end

  def input
    input_game
    input_level_editor
  end

  def input_up?
    inputs.keyboard.w || inputs.keyboard.up
  end

  def input_down?
    inputs.keyboard.s || inputs.keyboard.down
  end

  def input_left?
    inputs.keyboard.a || inputs.keyboard.left
  end

  def input_right?
    inputs.keyboard.d || inputs.keyboard.right
  end

  def input_game
    if inputs.keyboard.key_down.g
      state.level_editor_mode = !state.level_editor_mode
    end

    if player.on_floor
      if inputs.keyboard.q
        player.dx = -5
      elsif inputs.keyboard.e
        player.dx = 5
      end
    end

    if inputs.keyboard.key_down.space && !state.anchor_point
      state.tongue_length = 0
      state.action = :shooting
    elsif inputs.keyboard.key_down.space
      state.action = :aiming
      state.anchor_point  = nil
      state.tongue_length = 100
    end

    if state.anchor_point
      vector = state.tongue_angle.to_vector

      if input_up?
        state.tongue_length -= 5
        player.dy += vector.y
        player.dx += vector.x
      elsif input_down?
        state.tongue_length += 5
        player.dy -= vector.y
        player.dx -= vector.x
      end

      if input_left?
        player.dx -= 0.5
      elsif input_right?
        player.dx += 0.5
      end
    else
      if input_left?
        state.tongue_angle += 1.5
        state.tongue_angle = state.tongue_angle
      elsif input_right?
        state.tongue_angle -= 1.5
        state.tongue_angle = state.tongue_angle
      end
    end
  end

  def input_level_editor
    return unless state.level_editor_mode

    if Kernel.tick_count.mod_zero?(5)
      # zoom
      if inputs.keyboard.equal_sign || inputs.keyboard.plus
        set_camera_scale state.camera_scale + 0.1
      elsif inputs.keyboard.hyphen
        set_camera_scale state.camera_scale - 0.1
      elsif inputs.keyboard.zero
        set_camera_scale 0.5
      end

      # change wall width
      if inputs.keyboard.h
        state.level_editor_rect_w -= state.tile_size
      elsif inputs.keyboard.l
        state.level_editor_rect_w += state.tile_size
      end

      state.level_editor_rect_w = state.tile_size if state.level_editor_rect_w < state.tile_size

      # change wall height
      if inputs.keyboard.j
        state.level_editor_rect_h -= state.tile_size
      elsif inputs.keyboard.k
        state.level_editor_rect_h += state.tile_size
      end

      state.level_editor_rect_h = state.tile_size if state.level_editor_rect_h < state.tile_size
    end

    if inputs.mouse.click
      x = ((state.camera_x + inputs.mouse.x) / state.camera_scale).ifloor(state.tile_size)
      y = ((state.camera_y + inputs.mouse.y) / state.camera_scale).ifloor(state.tile_size)
      # place mug
      if inputs.keyboard.m
        w = 32
        h = 32
        candidate_rect = { x: x, y: y, w: w, h: h }
        if inputs.keyboard.x
          mouse_rect = { x: (state.camera_x + inputs.mouse.x) / state.camera_scale,
                         y: (state.camera_y + inputs.mouse.y) / state.camera_scale,
                         w: 10,
                         h: 10 }
          to_remove = state.mugs.find do |r|
            r.intersect_rect? mouse_rect
          end
          if to_remove
            state.mugs.reject! { |r| r == to_remove }
          end
        else
          exists = state.mugs.find { |r| r == candidate_rect }
          if !exists
            state.mugs << candidate_rect.merge(path: "sprites/square/orange.png")
          end
        end
      else
        # place wall
        w = state.level_editor_rect_w
        h = state.level_editor_rect_h
        candidate_rect = { x: x, y: y, w: w, h: h }
        if inputs.keyboard.x
          mouse_rect = { x: (state.camera_x + inputs.mouse.x) / state.camera_scale,
                         y: (state.camera_y + inputs.mouse.y) / state.camera_scale,
                         w: 10,
                         h: 10 }
          to_remove = state.walls.find do |r|
            r.intersect_rect? mouse_rect
          end
          if to_remove
            state.walls.reject! { |r| r == to_remove }
          end
        else
          exists = state.walls.find { |r| r == candidate_rect }
          if !exists
            state.walls << candidate_rect
          end
        end
      end

      save
    end

    if input_up?
      player.y += 10
      player.dy = 0
    elsif input_down?
      player.y -= 10
      player.dy = 0
    end

    if input_left?
      player.x -= 10
      player.dx = 0
    elsif input_right?
      player.x += 10
      player.dx = 0
    end
  end

  def end_of_tongue
    p = state.tongue_angle.to_vector
    { x: start_of_tongue.x + p.x * state.tongue_length,
      y: start_of_tongue.y + p.y * state.tongue_length }
  end

  def save
    $gtk.write_file("data/mugs.txt", "")
    state.mugs.each do |o|
      $gtk.append_file "data/mugs.txt", "#{o.x},#{o.y},#{o.w},#{o.h}\n"
    end

    $gtk.write_file("data/walls.txt", "")
    state.walls.map do |o|
      $gtk.append_file "data/walls.txt", "#{o.x},#{o.y},#{o.w},#{o.h}\n"
    end
  end

  def load_if_needed
    return if state.walls
    state.walls = []
    state.mugs = []

    contents = $gtk.read_file "data/mugs.txt"
    if contents
      contents.each_line do |l|
        x, y, w, h = l.split(',').map(&:to_i)
        state.mugs << { x: x.ifloor(state.tile_size),
                        y: y.ifloor(state.tile_size),
                        w: w,
                        h: h,
                        path: "sprites/square/orange.png" }
      end
    end

    contents = $gtk.read_file "data/walls.txt"
    if contents
      contents.each_line do |l|
        x, y, w, h = l.split(',').map(&:to_i)
        state.walls << { x: x.ifloor(state.tile_size),
                         y: y.ifloor(state.tile_size),
                         w: w,
                         h: h,
                         path: :pixel,
                         r: 128,
                         g: 128,
                         b: 128,
                         a: 128 }
      end
    end
  end
end

$game = CleptoFrog.new

def tick args
  $game.args = args
  $game.tick
end

# $gtk.reset

Clepto Frog - Data - mugs.txt link

# ./samples/99_genre_platformer/clepto_frog/data/mugs.txt
64,64,32,32
928,1952,32,32
3744,2464,32,32
1536,3264,32,32
7648,32,32,32
9312,1120,32,32
7296,1152,32,32
5792,1824,32,32
864,3744,32,32
1024,4640,32,32
800,5312,32,32
3232,5216,32,32
4736,5280,32,32
9312,5152,32,32
9632,4288,32,32
7808,4096,32,32
8640,1952,32,32
6880,2016,32,32
4608,3872,32,32
4000,4544,32,32
3200,3328,32,32
5056,1056,32,32
3424,608,32,32
6496,288,32,32
6080,288,32,32
5600,288,32,32
3424,608,32,32
2656,704,32,32
2208,224,32,32

Clepto Frog - Data - walls.txt link

# ./samples/99_genre_platformer/clepto_frog/data/walls.txt
0,0,32,5664
0,5664,10016,32
0,0,10016,32
10016,0,32,5696
2112,192,704,32
2112,672,704,32
3328,576,224,32
5504,256,256,32
5984,256,256,32
6400,256,256,32
4928,1024,256,32
7168,1120,256,32
9216,1088,256,32
8544,1920,256,32
6752,1984,256,32
5664,1792,256,32
832,1920,256,32
1440,3232,256,32
736,3712,256,32
896,4608,256,32
672,5280,256,32
3136,5184,256,32
3872,4512,256,32
4640,5248,256,32
7680,4064,256,32
9536,4256,256,32
9184,5120,256,32
3072,3296,256,32
3616,2432,256,32
4480,3840,256,32
4704,1952,128,128
6272,3328,128,128
5248,4832,128,128
2496,4320,128,128
1536,5056,128,128
7232,5024,128,128
2208,2336,128,128
1120,704,128,128
8448,2944,128,128
8576,4608,128,128
7840,2176,128,128
8640,416,128,128
6048,1088,128,128
4768,352,128,128
3040,1600,128,128
448,2720,128,128
1568,4064,128,128
256,4736,128,128
3936,5312,128,128
3872,3360,128,128
7904,800,128,128
6272,4320,128,128
1728,1440,128,128
96,768,128,128
9120,3616,128,128
6144,5184,128,128
7168,3168,128,128
5472,3712,128,128
2592,5088,128,128
2528,3328,128,128
1376,2560,128,128
4096,1344,128,128
9344,2336,128,128
5952,2656,128,128
3360,4160,128,128
224,1696,128,128
352,4064,128,128
8192,5248,128,128
7168,448,128,128
6624,2592,128,128
4608,2848,128,128
2336,1184,128,128
640,224,128,128
7264,4352,128,128

Gorillas Basic - credits.txt link

# ./samples/99_genre_platformer/gorillas_basic/CREDITS.txt
code: Amir Rajan, https://twitter.com/amirrajan
graphics: Nick Culbertson, https://twitter.com/MobyPixel

Gorillas Basic - main.rb link

# ./samples/99_genre_platformer/gorillas_basic/app/main.rb
class YouSoBasicGorillas
  attr_accessor :outputs, :grid, :state, :inputs

  def tick
    defaults
    render
    calc
    process_inputs
  end

  def defaults
    outputs.background_color = [33, 32, 87]
    state.building_spacing       = 1
    state.building_room_spacing  = 15
    state.building_room_width    = 10
    state.building_room_height   = 15
    state.building_heights       = [4, 4, 6, 8, 15, 20, 18]
    state.building_room_sizes    = [5, 4, 6, 7]
    state.gravity                = 0.25
    state.first_strike         ||= :player_1
    state.buildings            ||= []
    state.holes                ||= []
    state.player_1_score       ||= 0
    state.player_2_score       ||= 0
    state.wind                 ||= 0
  end

  def render
    render_stage
    render_value_insertion
    render_gorillas
    render_holes
    render_banana
    render_game_over
    render_score
    render_wind
  end

  def render_score
    outputs.primitives << [0, 0, 1280, 31, fancy_white].solid
    outputs.primitives << [1, 1, 1279, 29].solid
    outputs.labels << [  10, 25, "Score: #{state.player_1_score}", 0, 0, fancy_white]
    outputs.labels << [1270, 25, "Score: #{state.player_2_score}", 0, 2, fancy_white]
  end

  def render_wind
    outputs.primitives << [640, 12, state.wind * 500 + state.wind * 10 * rand, 4, 35, 136, 162].solid
    outputs.lines     <<  [640, 30, 640, 0, fancy_white]
  end

  def render_game_over
    return unless state.over
    outputs.primitives << [grid.rect, 0, 0, 0, 200].solid
    outputs.primitives << [640, 370, "Game Over!!", 5, 1, fancy_white].label
    if state.winner == :player_1
      outputs.primitives << [640, 340, "Player 1 Wins!!", 5, 1, fancy_white].label
    else
      outputs.primitives << [640, 340, "Player 2 Wins!!", 5, 1, fancy_white].label
    end
  end

  def render_stage
    return unless state.stage_generated
    return if state.stage_rendered

    outputs.static_solids << [grid.rect, 33, 32, 87]
    outputs.static_solids << state.buildings.map(&:solids)
    state.stage_rendered = true
  end

  def render_gorilla gorilla, id
    return unless gorilla
    if state.banana && state.banana.owner == gorilla
      animation_index  = state.banana.created_at.frame_index(3, 5, false)
    end
    if !animation_index
      outputs.sprites << [gorilla.solid, "sprites/#{id}-idle.png"]
    else
      outputs.sprites << [gorilla.solid, "sprites/#{id}-#{animation_index}.png"]
    end
  end

  def render_gorillas
    render_gorilla state.player_1, :left
    render_gorilla state.player_2, :right
  end

  def render_value_insertion
    return if state.banana
    return if state.over

    if    state.current_turn == :player_1_angle
      outputs.labels << [  10, 710, "Angle:    #{state.player_1_angle}_",    fancy_white]
    elsif state.current_turn == :player_1_velocity
      outputs.labels << [  10, 710, "Angle:    #{state.player_1_angle}",     fancy_white]
      outputs.labels << [  10, 690, "Velocity: #{state.player_1_velocity}_", fancy_white]
    elsif state.current_turn == :player_2_angle
      outputs.labels << [1120, 710, "Angle:    #{state.player_2_angle}_",    fancy_white]
    elsif state.current_turn == :player_2_velocity
      outputs.labels << [1120, 710, "Angle:    #{state.player_2_angle}",     fancy_white]
      outputs.labels << [1120, 690, "Velocity: #{state.player_2_velocity}_", fancy_white]
    end
  end

  def render_banana
    return unless state.banana
    rotation = Kernel.tick_count.%(360) * 20
    rotation *= -1 if state.banana.dx > 0
    outputs.sprites << [state.banana.x, state.banana.y, 15, 15, 'sprites/banana.png', rotation]
  end

  def render_holes
    outputs.sprites << state.holes.map do |s|
      animation_index = s.created_at.frame_index(7, 3, false)
      if animation_index
        [s.sprite, [s.sprite.rect, "sprites/explosion#{animation_index}.png" ]]
      else
        s.sprite
      end
    end
  end

  def calc
    calc_generate_stage
    calc_current_turn
    calc_banana
  end

  def calc_current_turn
    return if state.current_turn

    state.current_turn = :player_1_angle
    state.current_turn = :player_2_angle if state.first_strike == :player_2
  end

  def calc_generate_stage
    return if state.stage_generated

    state.buildings << building_prefab(state.building_spacing + -20, *random_building_size)
    8.numbers.inject(state.buildings) do |buildings, i|
      buildings <<
        building_prefab(state.building_spacing +
                        state.buildings.last.right,
                        *random_building_size)
    end

    building_two = state.buildings[1]
    state.player_1 = new_player(building_two.x + building_two.w.fdiv(2),
                               building_two.h)

    building_nine = state.buildings[-3]
    state.player_2 = new_player(building_nine.x + building_nine.w.fdiv(2),
                               building_nine.h)
    state.stage_generated = true
    state.wind = 1.randomize(:ratio, :sign)
  end

  def new_player x, y
    state.new_entity(:gorilla) do |p|
      p.x = x - 25
      p.y = y
      p.solid = [p.x, p.y, 50, 50]
    end
  end

  def calc_banana
    return unless state.banana

    state.banana.x  += state.banana.dx
    state.banana.dx += state.wind.fdiv(50)
    state.banana.y  += state.banana.dy
    state.banana.dy -= state.gravity
    banana_collision = [state.banana.x, state.banana.y, 10, 10]

    if state.player_1 && banana_collision.intersect_rect?(state.player_1.solid)
      state.over = true
      if state.banana.owner == state.player_2
        state.winner = :player_2
      else
        state.winner = :player_1
      end

      state.player_2_score += 1
    elsif state.player_2 && banana_collision.intersect_rect?(state.player_2.solid)
      state.over = true
      if state.banana.owner == state.player_2
        state.winner = :player_1
      else
        state.winner = :player_2
      end
      state.player_1_score += 1
    end

    if state.over
      place_hole
      return
    end

    return if state.holes.any? do |h|
      h.sprite.scale_rect(0.8, 0.5, 0.5).intersect_rect? [state.banana.x, state.banana.y, 10, 10]
    end

    return unless state.banana.y < 0 || state.buildings.any? do |b|
      b.rect.intersect_rect? [state.banana.x, state.banana.y, 1, 1]
    end

    place_hole
  end

  def place_hole
    return unless state.banana

    state.holes << state.new_entity(:banana) do |b|
      b.sprite = [state.banana.x - 20, state.banana.y - 20, 40, 40, 'sprites/hole.png']
    end

    state.banana = nil
  end

  def process_inputs_main
    return if state.banana
    return if state.over

    if inputs.keyboard.key_down.enter
      input_execute_turn
    elsif inputs.keyboard.key_down.backspace
      state.as_hash[state.current_turn] ||= ""
      state.as_hash[state.current_turn]   = state.as_hash[state.current_turn][0..-2]
    elsif inputs.keyboard.key_down.char
      state.as_hash[state.current_turn] ||= ""
      state.as_hash[state.current_turn]  += inputs.keyboard.key_down.char
    end
  end

  def process_inputs_game_over
    return unless state.over
    return unless inputs.keyboard.key_down.truthy_keys.any?
    state.over = false
    outputs.static_solids.clear
    state.buildings.clear
    state.holes.clear
    state.stage_generated = false
    state.stage_rendered = false
    if state.first_strike == :player_1
      state.first_strike = :player_2
    else
      state.first_strike = :player_1
    end
  end

  def process_inputs
    process_inputs_main
    process_inputs_game_over
  end

  def input_execute_turn
    return if state.banana

    if state.current_turn == :player_1_angle && parse_or_clear!(:player_1_angle)
      state.current_turn = :player_1_velocity
    elsif state.current_turn == :player_1_velocity && parse_or_clear!(:player_1_velocity)
      state.current_turn = :player_2_angle
      state.banana =
        new_banana(state.player_1,
                   state.player_1.x + 25,
                   state.player_1.y + 60,
                   state.player_1_angle,
                   state.player_1_velocity)
    elsif state.current_turn == :player_2_angle && parse_or_clear!(:player_2_angle)
      state.current_turn = :player_2_velocity
    elsif state.current_turn == :player_2_velocity && parse_or_clear!(:player_2_velocity)
      state.current_turn = :player_1_angle
      state.banana =
        new_banana(state.player_2,
                   state.player_2.x + 25,
                   state.player_2.y + 60,
                   180 - state.player_2_angle,
                   state.player_2_velocity)
    end

    if state.banana
      state.player_1_angle = nil
      state.player_1_velocity = nil
      state.player_2_angle = nil
      state.player_2_velocity = nil
    end
  end

  def random_building_size
    [state.building_heights.sample, state.building_room_sizes.sample]
  end

  def int? v
    v.to_i.to_s == v.to_s
  end

  def random_building_color
    [[ 99,   0, 107],
     [ 35,  64, 124],
     [ 35, 136, 162],
     ].sample
  end

  def random_window_color
    [[ 88,  62, 104],
     [253, 224, 187]].sample
  end

  def windows_for_building starting_x, floors, rooms
    floors.-(1).combinations(rooms - 1).map do |floor, room|
      [starting_x +
       state.building_room_width.*(room) +
       state.building_room_spacing.*(room + 1),
       state.building_room_height.*(floor) +
       state.building_room_spacing.*(floor + 1),
       state.building_room_width,
       state.building_room_height,
       random_window_color]
    end
  end

  def building_prefab starting_x, floors, rooms
    state.new_entity(:building) do |b|
      b.x      = starting_x
      b.y      = 0
      b.w      = state.building_room_width.*(rooms) +
                 state.building_room_spacing.*(rooms + 1)
      b.h      = state.building_room_height.*(floors) +
                 state.building_room_spacing.*(floors + 1)
      b.right  = b.x + b.w
      b.rect   = [b.x, b.y, b.w, b.h]
      b.solids = [[b.x - 1, b.y, b.w + 2, b.h + 1, fancy_white],
                  [b.x, b.y, b.w, b.h, random_building_color],
                  windows_for_building(b.x, floors, rooms)]
    end
  end

  def parse_or_clear! game_prop
    if int? state.as_hash[game_prop]
      state.as_hash[game_prop] = state.as_hash[game_prop].to_i
      return true
    end

    state.as_hash[game_prop] = nil
    return false
  end

  def new_banana owner, x, y, angle, velocity
    state.new_entity(:banana) do |b|
      b.owner     = owner
      b.x         = x
      b.y         = y
      b.angle     = angle % 360
      b.velocity  = velocity / 5
      b.dx        = b.angle.vector_x(b.velocity)
      b.dy        = b.angle.vector_y(b.velocity)
    end
  end

  def fancy_white
    [253, 252, 253]
  end
end

$you_so_basic_gorillas = YouSoBasicGorillas.new

def tick args
  $you_so_basic_gorillas.outputs = args.outputs
  $you_so_basic_gorillas.grid    = args.grid
  $you_so_basic_gorillas.state    = args.state
  $you_so_basic_gorillas.inputs  = args.inputs
  $you_so_basic_gorillas.tick
end

Map Editor - camera.rb link

# ./samples/99_genre_platformer/map_editor/app/camera.rb
class Camera
  SCREEN_WIDTH = 1280
  SCREEN_HEIGHT = 720
  WORLD_SIZE = 1500
  WORLD_SIZE_HALF = WORLD_SIZE / 2
  OFFSET_X = (SCREEN_WIDTH - WORLD_SIZE) / 2
  OFFSET_Y = (SCREEN_HEIGHT - WORLD_SIZE) / 2

  class << self
    def to_world_space camera, rect
      x = (rect.x - WORLD_SIZE_HALF + camera.x * camera.scale - OFFSET_X) / camera.scale
      y = (rect.y - WORLD_SIZE_HALF + camera.y * camera.scale - OFFSET_Y) / camera.scale
      w = rect.w / camera.scale
      h = rect.h / camera.scale
      rect.merge x: x, y: y, w: w, h: h
    end

    def to_screen_space camera, rect
      x = rect.x * camera.scale - camera.x * camera.scale + WORLD_SIZE_HALF
      y = rect.y * camera.scale - camera.y * camera.scale + WORLD_SIZE_HALF
      w = rect.w * camera.scale
      h = rect.h * camera.scale
      rect.merge x: x, y: y, w: w, h: h
    end

    def viewport
      {
        x: OFFSET_X,
        y: OFFSET_Y,
        w: 1500,
        h: 1500
      }
    end

    def viewport_world camera
      to_world_space camera, viewport
    end

    def find_all_intersect_viewport camera, os
      Geometry.find_all_intersect_rect viewport_world(camera), os
    end
  end
end

Map Editor - level_editor.rb link

# ./samples/99_genre_platformer/map_editor/app/level_editor.rb
class LevelEditor
  attr_gtk
  attr :mode, :hovered_tile, :selected_tile, :tilesheet_rect

  def initialize
    @tilesheet_rect = { x: 0, y: 0, w: 320, h: 320 }
    @mode = :add
  end

  def tick
    generate_tilesheet
    calc
    render
  end

  def calc
    if inputs.keyboard.x
      @mode = :remove
    else
      @mode = :add
    end

    if !@selected_tile
      @mode = :remove
    elsif @selected_tile.x_ordinal == 0 && @selected_tile.y_ordinal == 0
      @mode = :remove
    end

    if mouse.intersect_rect? @tilesheet_rect
      x_ordinal = mouse.x.idiv(16)
      y_ordinal = mouse.y.idiv(16)
      @hovered_tile = { x_ordinal: mouse.x.idiv(16),
                        x: mouse.x.idiv(16) * 16,
                        y_ordinal: mouse.x.idiv(16),
                        y: mouse.y.idiv(16) * 16,
                        row: 20 - y_ordinal - 1,
                        col: x_ordinal,
                        path: tile_path(20 - y_ordinal - 1, x_ordinal, 20),
                        w: 16,
                        h: 16 }
    else
      @hovered_tile = nil
    end

    if mouse.click && @hovered_tile
      @selected_tile = @hovered_tile
    end

    world_mouse = Camera.to_world_space state.camera, inputs.mouse
    ifloor_x = world_mouse.x.ifloor(16)
    ifloor_y = world_mouse.y.ifloor(16)

    @mouse_world_rect =  { x: ifloor_x,
                           y: ifloor_y,
                           w: 16,
                           h: 16 }

    if @selected_tile
      ifloor_x = world_mouse.x.ifloor(16)
      ifloor_y = world_mouse.y.ifloor(16)
      @selected_tile.x = @mouse_world_rect.x
      @selected_tile.y = @mouse_world_rect.y
    end

    if @mode == :remove && (mouse.click || (mouse.held && mouse.moved))
      state.terrain.reject! { |t| t.intersect_rect? @mouse_world_rect }
      save_terrain args
    elsif @selected_tile && (mouse.click || (mouse.held && mouse.moved))
      if @mode == :add
        state.terrain.reject! { |t| t.intersect_rect? @selected_tile }
        state.terrain << @selected_tile.copy
      else
        state.terrain.reject! { |t| t.intersect_rect? @selected_tile }
      end
      save_terrain args
    end
  end

  def render
    outputs.sprites << { x: 0, y: 0, w: 320, h: 320, path: :tilesheet }

    if @hovered_tile
      outputs.sprites << { x: @hovered_tile.x,
                           y: @hovered_tile.y,
                           w: 16,
                           h: 16,
                           path: :pixel,
                           r: 255, g: 0, b: 0, a: 128 }
    end

    if @selected_tile
      if @mode == :remove
        outputs[:scene].sprites << (Camera.to_screen_space state.camera, @selected_tile).merge(path: :pixel, r: 255, g: 0, b: 0, a: 64)
      elsif @selected_tile
        outputs[:scene].sprites << (Camera.to_screen_space state.camera, @selected_tile)
        outputs[:scene].sprites << (Camera.to_screen_space state.camera, @selected_tile).merge(path: :pixel, r: 0, g: 255, b: 255, a: 64)
      end
    end
  end

  def generate_tilesheet
    return if state.tick_count > 0
    results = []
    rows = 20
    cols = 20
    tile_size = 16
    height = rows * tile_size
    width = cols * tile_size
    rows.map_with_index do |row|
      cols.map_with_index do |col|
        results << {
          x: col * tile_size,
          y: height - row * tile_size - tile_size,
          w: tile_size,
          h: tile_size,
          path: tile_path(row, col, cols)
        }
      end
    end

    outputs[:tilesheet].w = width
    outputs[:tilesheet].h = height
    outputs[:tilesheet].sprites << { x: 0, y: 0, w: width, h: height, path: :pixel, r: 0, g: 0, b: 0 }
    outputs[:tilesheet].sprites << results
  end

  def mouse
    inputs.mouse
  end

  def tile_path row, col, cols
    file_name = (tile_index row, col, cols).to_s.rjust(4, "0")
    "sprites/1-bit-platformer/#{file_name}.png"
  end

  def tile_index row, col, cols
    row * cols + col
  end

  def save_terrain args
    contents = args.state.terrain.uniq.map do |terrain_element|
      "#{terrain_element.x.to_i},#{terrain_element.y.to_i},#{terrain_element.w.to_i},#{terrain_element.h.to_i},#{terrain_element.path}"
    end
    File.write "data/terrain.txt", contents.join("\n")
  end

  def load_terrain args
    args.state.terrain = []
    contents = File.read("data/terrain.txt")
    return if !contents
    args.state.terrain = contents.lines.map do |line|
      l = line.strip
      if l.empty?
        nil
      else
        x, y, w, h, path = l.split ","
        { x: x.to_f, y: y.to_f, w: w.to_f, h: h.to_f, path: path }
      end
    end.compact.to_a.uniq
  end
end

Map Editor - main.rb link

# ./samples/99_genre_platformer/map_editor/app/main.rb
require 'app/level_editor.rb'
require 'app/root_scene.rb'
require 'app/camera.rb'

def tick args
  $root_scene ||= RootScene.new args
  $root_scene.args = args
  $root_scene.tick
end

def reset
  $root_scene = nil
end

$gtk.reset

Map Editor - root_scene.rb link

# ./samples/99_genre_platformer/map_editor/app/root_scene.rb
class RootScene
  attr_gtk

  attr :level_editor

  def initialize args
    @level_editor = LevelEditor.new
  end

  def tick
    args.outputs.background_color = [0, 0, 0]
    args.state.terrain ||= []
    @level_editor.load_terrain args if args.state.tick_count == 0

    state.player ||= {
      x: 0,
      y: 750,
      w: 16,
      h: 16,
      dy: 0,
      dx: 0,
      on_ground: false,
      path: "sprites/1-bit-platformer/0280.png"
    }

    if inputs.keyboard.left
      player.dx = -3
    elsif inputs.keyboard.right
      player.dx = 3
    end

    if inputs.keyboard.key_down.space && player.on_ground
      player.dy = 10
      player.on_ground = false
    end

    if args.inputs.keyboard.key_down.equal_sign || args.inputs.keyboard.key_down.plus
      state.camera.target_scale += 0.25
    elsif args.inputs.keyboard.key_down.minus
      state.camera.target_scale -= 0.25
      state.camera.target_scale = 0.25 if state.camera.target_scale < 0.25
    elsif args.inputs.keyboard.zero
      state.camera.target_scale = 1
    end

    state.gravity ||= 0.25
    calc_camera
    calc_physics
    outputs[:scene].w = 1500
    outputs[:scene].h = 1500
    outputs[:scene].background_color = [0, 0, 0, 0]
    outputs[:scene].lines << { x: 0, y: 0, x2: 1500, y2: 1500, r: 255, g: 255, b: 255, a: 255 }
    outputs[:scene].lines << { x: 0, y: 1500, x2: 1500, y2: 0, r: 255, g: 255, b: 255, a: 255 }
    outputs[:scene].sprites << player_prefab

    terrain_to_render = Camera.find_all_intersect_viewport(state.camera, state.terrain)
    outputs[:scene].sprites << terrain_to_render.map do |m|
      Camera.to_screen_space(state.camera, m)
    end

    outputs.sprites << { **Camera.viewport, path: :scene }

    @level_editor.args = args
    @level_editor.tick

    outputs.labels << { x: 640,
                        y: 30.from_top,
                        anchor_x: 0.5,
                        text: "WASD: move around. SPACE: jump. +/-: Zoom in and out. MOUSE: select tile/edit map (hold X and CLICK to delete).",
                        r: 255,
                        g: 255,
                        b: 255 }
  end

  def calc_camera
    state.world_size ||= 1280

    if !state.camera
      state.camera = {
        x: 0,
        y: 0,
        target_x: 0,
        target_y: 0,
        target_scale: 2,
        scale: 1
      }
    end

    ease = 0.1
    state.camera.scale += (state.camera.target_scale - state.camera.scale) * ease
    state.camera.target_x = player.x
    state.camera.target_y = player.y

    state.camera.x += (state.camera.target_x - state.camera.x) * ease
    state.camera.y += (state.camera.target_y - state.camera.y) * ease
  end

  def calc_physics
    player.x += player.dx
    collision = state.terrain.find do |t|
      t.intersect_rect? player
    end

    if collision
      if player.dx > 0
        player.x = collision.x - player.w
      else
        player.x = collision.x + collision.w
      end

      player.dx = 0
    end

    player.dx *= 0.8
    if player.dx.abs < 0.5
      player.dx = 0
    end

    player.y += player.dy
    player.on_ground = false

    collision = state.terrain.find do |t|
      t.intersect_rect? player
    end

    if collision
      if player.dy > 0
        player.y = collision.y - player.h
      else
        player.y = collision.y + collision.h
        player.on_ground = true
      end
      player.dy = 0
    end

    player.dy -= state.gravity

    if (player.y + player.h) < -750
      player.y = 750
      player.dy = 0
    end
  end

  def player
    state.player
  end

  def player_prefab
    prefab = Camera.to_screen_space state.camera, (player.merge path: "sprites/1-bit-platformer/0280.png")

    if !player.on_ground
      prefab.merge! path: "sprites/1-bit-platformer/0284.png"
      if player.dx > 0
        prefab.merge! flip_horizontally: false
      elsif player.dx < 0
        prefab.merge! flip_horizontally: true
      end
    elsif player.dx > 0
      frame_index = 0.frame_index 3, 5, true
      prefab.merge! path: "sprites/1-bit-platformer/028#{frame_index + 1}.png"
    elsif player.dx < 0
      frame_index = 0.frame_index 3, 5, true
      prefab.merge! path: "sprites/1-bit-platformer/028#{frame_index + 1}.png", flip_horizontally: true
    end

    prefab
  end

  def camera
    state.camera
  end

  def should_update_matricies?
    player.dx != 0 || player.dy != 0
  end
end

Map Editor - Data - terrain.txt link

# ./samples/99_genre_platformer/map_editor/data/terrain.txt
0,368,16,16,sprites/1-bit-platformer/0088.png
-16,368,16,16,sprites/1-bit-platformer/0088.png
-32,368,16,16,sprites/1-bit-platformer/0088.png
-48,368,16,16,sprites/1-bit-platformer/0088.png
-64,368,16,16,sprites/1-bit-platformer/0088.png
-80,368,16,16,sprites/1-bit-platformer/0088.png
16,368,16,16,sprites/1-bit-platformer/0088.png
32,368,16,16,sprites/1-bit-platformer/0088.png
48,368,16,16,sprites/1-bit-platformer/0088.png
64,368,16,16,sprites/1-bit-platformer/0088.png
80,368,16,16,sprites/1-bit-platformer/0088.png
-96,368,16,16,sprites/1-bit-platformer/0087.png
96,368,16,16,sprites/1-bit-platformer/0089.png
-96,352,16,16,sprites/1-bit-platformer/0127.png
-80,352,16,16,sprites/1-bit-platformer/0128.png
-64,352,16,16,sprites/1-bit-platformer/0128.png
-48,352,16,16,sprites/1-bit-platformer/0128.png
-32,352,16,16,sprites/1-bit-platformer/0128.png
-16,352,16,16,sprites/1-bit-platformer/0128.png
0,352,16,16,sprites/1-bit-platformer/0128.png
16,352,16,16,sprites/1-bit-platformer/0128.png
32,352,16,16,sprites/1-bit-platformer/0128.png
48,352,16,16,sprites/1-bit-platformer/0128.png
64,352,16,16,sprites/1-bit-platformer/0128.png
80,352,16,16,sprites/1-bit-platformer/0128.png
96,352,16,16,sprites/1-bit-platformer/0129.png

Shadows - main.rb link

# ./samples/99_genre_platformer/shadows/app/main.rb
# demo gameplay here: https://youtu.be/wQknjYk_-dE
# this is the core game class. the game is
# pretty small so this is the only class that was created
class Game
  # attr_gtk is a ruby class macro (mixin) that
  # adds the .args, .inputs, .outputs, and .state
  # properties to a class
  attr_gtk

  # this is the main tick method that
  # will be called every frame
  # the tick method is your standard game loop.
  # ie initialize game state, process input,
  #    perform simulation calculations, then render
  def tick
    defaults
    input
    calc
    render
  end

  # defaults method re-initializes the game to its
  # starting point if
  # 1. it hasn't already been initialized (state.clock is nil)
  # 2. or reinitializes the game if the player died (game_over)
  def defaults
    new_game if !state.clock || state.game_over == true
  end

  # this is where inputs are processed
  # we process inputs for the player via input_entity
  # and then process inputs for each enemy using the same
  # input_entity function
  def input
    input_entity player,
                 find_input_timeline(at: player.clock, key: :left_right),
                 find_input_timeline(at: player.clock, key: :space),
                 find_input_timeline(at: player.clock, key: :down)

    # an enemy could still be spawing
    shadows.find_all { |shadow| entity_active? shadow }
           .each do |shadow|
             input_entity shadow,
                          find_input_timeline(at: shadow.clock, key: :left_right),
                          find_input_timeline(at: shadow.clock, key: :space),
                          find_input_timeline(at: shadow.clock, key: :down)
             end
  end

  # this is the input_entity function that handles
  # the movement of the player (and the enemies)
  # it's essentially your state machine for player
  # movement
  def input_entity entity, left_right, jump, fall_through
    # guard clause that ignores input processing if
    # the entity is still spawning
    return if !entity_active? entity

    # increment the dx of the entity by the magnitude of
    # the left_right input value
    entity.dx += left_right

    # if the left_right input is zero...
    if left_right == 0
      # if the entity was originally running, then
      # set their "action" to standing
      # entity_set_action! updates the current action
      # of the entity and takes note of the frame that
      # the action occured on
      if (entity.action == :running)
        entity_set_action! entity, :standing
      end
    elsif entity.left_right != left_right && (entity_on_platform? entity)
      # if the entity is on a platform, and their current
      # left right value is different, mark them as running
      # this is done because we want to reset the run animation
      # if they changed directions
      entity_set_action! entity, :running
    end

    # capture the left_right input so that it can be
    # consulted on the next frame
    entity.left_right = left_right

    # capture the direction the player is facing
    # (this is used to determine the horizontal flip of the
    # sprite
    entity.orientation = if left_right == -1
                           :left
                         elsif left_right == 1
                           :right
                         else
                           entity.orientation
                         end

    # if the fall_through (down) input was requested,
    # and if they are on a platform...
    if fall_through && (entity_on_platform? entity)
      entity.jumped_at      = 0
      # set their jump_down value (falling through a platform)
      entity.jumped_down_at = entity.clock
      # and increment the number of times they jumped
      # (entities get three jumps before needing to touch the ground again)
      entity.jump_count    += 1
    end

    # if the jump input was requested
    # and if they haven't reached their jump limit
    if jump && entity.jump_count < 3
      # update the player's current action to the
      # corresponding jump number (used for rendering
      # the different jump animations)
      if entity.jump_count == 0
        entity_set_action! entity, :first_jump
      elsif entity.jump_count == 1
        entity_set_action! entity, :midair_jump
      elsif entity.jump_count == 2
        entity_set_action! entity, :midair_jump
      end

      # set the entity's dy value and take note
      # of when jump occured (also increment jump
      # count/eat one of their jumps)
      entity.dy             = entity.jump_power
      entity.jumped_at      = entity.clock
      entity.jumped_down_at = 0
      entity.jump_count    += 1
    end
  end

  # after inputs have been processed, we then
  # determine game over states, collision, win states
  # etc
  def calc
    # calculate the new values of the light meter
    # (if the light meter hits zero, it's game over)
    calc_light_meter

    # capture the actions that were taken this turn so
    # that they can be "replayed" for the enemies on future
    # ticks of the simulation
    calc_action_history

    # calculate collisions for the player
    calc_entity player

    # calculate collisions for the enemies
    calc_shadows

    # spawn a new light crystal
    calc_light_crystal

    # process "fire and forget" render queues
    # (eg particles and death animations)
    calc_render_queues

    # determine game over
    calc_game_over

    # increment the internal clocks for all entities
    # this internal clock is used to determine how
    # a player's past input is replayed. it's also
    # used to determine what animation frame the entity
    # should be performing when idle, running, and jumping
    calc_clock
  end

  # ease the light meters value up or down
  # every time the player captures a light crystal
  # the "target" light meter value is increased and
  # slowly spills over to the final light meter value
  # which is used to determine game over
  def calc_light_meter
    state.light_meter -= 1
    d = state.light_meter_queue * 0.1
    state.light_meter += d
    state.light_meter_queue -= d
  end

  def calc_action_history
    # keep track of the inputs the player has performed over time
    # as the inputs change for the player, mark the point in time
    # the specific input changed, and when the change occured.
    # when enemies replay the player's actions, this history (along
    # with the enemy's interal clock) is consulted to determine
    # what action should be performed

    # the three possible input events are captured and marked
    # within the input timeline if/when the value changes

    # left right input events
    state.curr_left_right     = inputs.left_right
    if state.prev_left_right != state.curr_left_right
      state.input_timeline.unshift({ at: state.clock, k: :left_right, v: state.curr_left_right })
    end
    state.prev_left_right = state.curr_left_right

    # jump input events
    state.curr_space     = inputs.keyboard.key_down.space    ||
                           inputs.controller_one.key_down.a  ||
                           inputs.keyboard.key_down.up       ||
                           inputs.controller_one.key_down.b
    if state.prev_space != state.curr_space
      state.input_timeline.unshift({ at: state.clock, k: :space, v: state.curr_space })
    end
    state.prev_space = state.curr_space

    # jump down (fall through platform)
    state.curr_down     = inputs.keyboard.down || inputs.controller_one.down
    if state.prev_down != state.curr_down
      state.input_timeline.unshift({ at: state.clock, k: :down, v: state.curr_down })
    end
    state.prev_down = state.curr_down
  end

  def calc_entity entity
    # process entity collision/simulation
    calc_entity_rect entity

    # return if the entity is still spawning
    return if !entity_active? entity

    # calc collisions
    calc_entity_collision entity

    # update the state machine of the entity based on the
    # collision results
    calc_entity_action entity

    # calc actions the entity should take based on
    # input timeline
    calc_entity_movement entity
  end

  def calc_entity_rect entity
    # this function calculates the entity's new
    # collision rect, render rect, hurt box, etc
    entity.render_rect = { x: entity.x, y: entity.y, w: entity.w, h: entity.h }
    entity.rect = entity.render_rect.merge x: entity.render_rect.x + entity.render_rect.w * 0.33,
                                           w: entity.render_rect.w * 0.33
    entity.next_rect = entity.rect.merge x: entity.x + entity.dx,
                                         y: entity.y + entity.dy
    entity.prev_rect = entity.rect.merge x: entity.x - entity.dx,
                                         y: entity.y - entity.dy
    orientation_shift = 0
    if entity.orientation == :right
      orientation_shift = entity.rect.w.half
    end
    entity.hurt_rect  = entity.rect.merge y: entity.rect.y + entity.h * 0.33,
                                          x: entity.rect.x - entity.rect.w.half + orientation_shift,
                                          h: entity.rect.h * 0.33
  end

  def calc_entity_collision entity
    # run of the mill AABB collision
    calc_entity_below entity
    calc_entity_left entity
    calc_entity_right entity
  end

  def calc_entity_below entity
    # exit ground collision detection if they aren't falling
    return unless entity.dy < 0
    tiles_below = find_tiles { |t| t.rect.top <= entity.prev_rect.y }
    collision = find_collision tiles_below, (entity.rect.merge y: entity.next_rect.y)

    # exit ground collision detection if no ground was found
    return unless collision

    # determine if the entity is allowed to fall through the platform
    # (you can only fall through a platform if you've been standing on it for 8 frames)
    can_drop = true
    if entity.last_standing_at && (entity.clock - entity.last_standing_at) < 8
      can_drop = false
    end

    # if the entity is allowed to fall through the platform,
    # and the entity requested the action, then clip them through the platform
    if can_drop && entity.jumped_down_at.elapsed_time(entity.clock) < 10 && !collision.impassable
      if (entity_on_platform? entity) && can_drop
        entity.dy = -1
      end

      entity.jump_count = 1
    else
      entity.y  = collision.rect.y + collision.rect.h
      entity.dy = 0
      entity.jump_count = 0
    end
  end

  def calc_entity_left entity
    # collision detection left side of screen
    return unless entity.dx < 0
    return if entity.next_rect.x > 8 - 32
    entity.x  = 8 - 32
    entity.dx = 0
  end

  def calc_entity_right entity
    # collision detection right side of screen
    return unless entity.dx > 0
    return if (entity.next_rect.x + entity.rect.w) < (1280 - 8 - 32)
    entity.x  = (1280 - 8 - entity.rect.w - 32)
    entity.dx = 0
  end

  def calc_entity_action entity
    # update the state machine of the entity
    # based on where they ended up after physics calculations
    if entity.dy < 0
      # mark the entity as falling after the jump animation frames
      # have been processed
      if entity.action == :midair_jump
        if entity_action_complete? entity, state.midair_jump_duration
          entity_set_action! entity, :falling
        end
      else
        entity_set_action! entity, :falling
      end
    elsif entity.dy == 0 && !(entity_on_platform? entity)
      # if the entity's dy is zero, determine if they should
      # be marked as standing or running
      if entity.left_right == 0
        entity_set_action! entity, :standing
      else
        entity_set_action! entity, :running
      end
    end
  end

  def calc_entity_movement entity
    # increment x and y positions of the entity
    # based on dy and dx
    calc_entity_dy entity
    calc_entity_dx entity
  end

  def calc_entity_dx entity
    # horizontal movement application and friction
    entity.dx  = entity.dx.clamp(-5,  5)
    entity.dx *= 0.9
    entity.x  += entity.dx
  end

  def calc_entity_dy entity
    # vertical movement application and gravity
    entity.y  += entity.dy
    entity.dy += state.gravity
    entity.dy += entity.dy * state.drag ** 2 * -1
  end

  def calc_shadows
    # every 5 seconds, add a new shadow enemy/increase difficult
    add_shadow! if state.clock.zmod?(300)

    # for each shadow, perform a simulation calculation
    shadows.each do |shadow|
      calc_entity shadow

      # decrement the spawn countdown which is used to determine if
      # the enemy is finally active
      shadow.spawn_countdown -= 1 if shadow.spawn_countdown > 0
    end
  end

  def calc_light_crystal
    # determine if the player has intersected with a light crystal
    light_rect = state.light_crystal
    if player.hurt_rect.intersect_rect? light_rect
      # if they have then queue up the partical animation of the
      # light crystal being collected
      state.jitter_fade_out_render_queue << { x:    state.light_crystal.x,
                                              y:    state.light_crystal.y,
                                              w:    state.light_crystal.w,
                                              h:    state.light_crystal.h,
                                              a:    255,
                                              path: 'sprites/light.png' }

      # increment the light meter target value
      state.light_meter_queue += 600

      # spawn a new light cristal for the player to try to get
      state.light_crystal = new_light_crystal
    end
  end

  def calc_render_queues
    # render all the entries in the "fire and forget" render queues
    state.jitter_fade_out_render_queue.each do |s|
      new_w = s.w * 1.02 ** 5
      ds = new_w - s.w
      s.w = new_w
      s.h = new_w
      s.x -= ds.half
      s.y -= ds.half
      s.a = s.a * 0.97 ** 5
    end

    state.jitter_fade_out_render_queue.reject! { |s| s.a <= 1 }

    state.game_over_render_queue.each { |s| s.a = s.a * 0.95 }
    state.game_over_render_queue.reject! { |s| s.a <= 1 }
  end

  def calc_game_over
    # calcuate game over
    state.game_over = false

    # it's game over if the player intersects with any of the enemies
    state.game_over ||= shadows.find_all { |s| s.spawn_countdown <= 0 }
                               .any? { |s| s.hurt_rect.intersect_rect? player.hurt_rect }

    # it's game over if the light_meter hits 0
    state.game_over ||= state.light_meter <= 1

    # debug to reset the game/prematurely
    if inputs.keyboard.key_down.r
      state.you_win = false
      state.game_over = true
    end

    # update game over states and win/loss
    if state.game_over
      state.you_win = false
      state.game_over = true
    end

    if state.light_meter >= 6000
      state.you_win = true
      state.game_over = true
    end

    # if it's a game over, fade out all current entities in play
    if state.game_over
      state.game_over_render_queue.concat shadows.map { |s| s.sprite.merge(a: 255) }
      state.game_over_render_queue << player.sprite.merge(a: 255)
      state.game_over_render_queue << state.light_crystal.merge(a: 255, path: 'sprites/light.png', b: 128)
    end
  end

  def calc_clock
    return if state.game_over
    state.clock += 1
    player.clock += 1
    shadows.each { |s| s.clock += 1 if entity_active? s }
  end

  def render
    # render the game
    render_stage
    render_light_meter
    render_instructions
    render_render_queues
    render_light_meter_warning
    render_light_crystal
    render_entities
  end

  def render_stage
    # the stage is a simple background
    outputs.background_color = [255, 255, 255]
    outputs.sprites << { x: 0,
                         y: 0,
                         w: 1280,
                         h: 720,
                         path: "sprites/stage.png",
                         a: 200 }
  end

  def render_light_meter
    # the light meter sprite is rendered across the top
    # how much of the light meter is light vs dark is based off
    # of what the current light meter value is (which increases
    # when a crystal is collected and decreses a little bit every
    # frame
    meter_perc = state.light_meter.fdiv(6000) + (0.002 * rand)
    light_w = (1280 * meter_perc).round
    dark_w  = 1280 - light_w

    # once the light and dark partitions have been computed
    # render the meter sprite and clip its width (source_w)
    outputs.sprites << { x: 0,
                         y: 64.from_top,
                         w: light_w,
                         source_x: 0,
                         source_y: 0,
                         source_w: light_w,
                         source_h: 128,
                         h: 64,
                         path: 'sprites/meter-light.png' }

    outputs.sprites << { x: 1280 * meter_perc,
                         y: 64.from_top,
                         w: dark_w,
                         source_x: light_w,
                         source_y: 0,
                         source_w: dark_w,
                         source_h: 128,
                         h: 64,
                         path: 'sprites/meter-dark.png' }
  end

  def render_instructions
    outputs.labels << { x: 640,
                        y: 40,
                        text: '[left/right] to move, [up/space] to jump, [down] to drop through platform',
                        alignment_enum: 1 }

    if state.you_win
      outputs.labels << { x: 640,
                          y: 40.from_top,
                          text: 'You win!',
                          size_enum: -1,
                          alignment_enum: 1 }
    end
  end

  def render_render_queues
    outputs.sprites << state.jitter_fade_out_render_queue
    outputs.sprites << state.game_over_render_queue
  end

  def render_light_meter_warning
    return if state.light_meter >= 255

    # the screen starts to dim if they are close to having
    # a game over because of a depleated light meter
    outputs.primitives << { x: 0,
                            y: 0,
                            w: 1280,
                            h: 720,
                            a: 255 - state.light_meter,
                            path: :pixel,
                            r: 0,
                            g: 0,
                            b: 0 }

    outputs.primitives << { x: state.light_crystal.x - 32,
                            y: state.light_crystal.y - 32,
                            w: 128,
                            h: 128,
                            a: 255 - state.light_meter,
                            path: 'sprites/spotlight.png' }
  end

  def render_light_crystal
    jitter_sprite = { x: state.light_crystal.x + 5 * rand,
                      y: state.light_crystal.y + 5 * rand,
                      w: state.light_crystal.w + 5 * rand,
                      h: state.light_crystal.h + 5 * rand,
                      path: 'sprites/light.png' }
    outputs.primitives << jitter_sprite
  end

  def render_entities
    render_entity player, r: 0, g: 0, b: 0
    shadows.each { |shadow| render_entity shadow, g: 0, b: 0 }
  end

  def render_entity entity, r: 255, g: 255, b: 255;
    # this is essentially the entity "prefab"
    # the current action of the entity is consulted to
    # determine what sprite should be rendered
    # the action_at time is consulted to determine which frame
    # of the sprite animation should be presented
    a = 255

    entity.sprite = nil

    if entity.activate_at
      activation_elapsed_time = state.clock - entity.activate_at
      if entity.activate_at > state.clock
        entity.sprite = { x: entity.initial_x + 5 * rand,
                          y: entity.initial_y + 5 * rand,
                          w: 64 + 5 * rand,
                          h: 64 + 5 * rand,
                          path: "sprites/light.png",
                          g: 0, b: 0,
                          a: a }

        outputs.sprites << entity.sprite
        return
      elsif !entity.activated
        entity.activated = true
        state.jitter_fade_out_render_queue << { x: entity.initial_x + 5 * rand,
                                                y: entity.initial_y + 5 * rand,
                                                w: 86 + 5 * rand, h: 86 + 5 * rand,
                                                path: "sprites/light.png",
                                                g: 0, b: 0, a: 255 }
      end
    end

    # this is the render outputs for an entities action state machine
    if entity.action == :standing
      path = "sprites/player/stand.png"
    elsif entity.action == :running
      sprint_index = entity.action_at
                           .frame_index count: 4,
                                        hold_for: 8,
                                        repeat: true,
                                        tick_count_override: entity.clock
      path = "sprites/player/run-#{sprint_index}.png"
    elsif entity.action == :first_jump
      sprint_index = entity.action_at
                           .frame_index count: 2,
                                        hold_for: 8,
                                        repeat: false,
                                        tick_count_override: entity.clock
      path = "sprites/player/jump-#{sprint_index || 1}.png"
    elsif entity.action == :midair_jump
      sprint_index = entity.action_at
                           .frame_index count: state.midair_jump_frame_count,
                                        hold_for: state.midair_jump_hold_for,
                                        repeat: false,
                                        tick_count_override: entity.clock
      path = "sprites/player/midair-jump-#{sprint_index || 8}.png"
    elsif entity.action == :falling
      path = "sprites/player/falling.png"
    end

    flip_horizontally = true if entity.orientation == :left
    entity.sprite = entity.render_rect.merge path: path,
                                             a: a,
                                             r: r,
                                             g: g,
                                             b: b,
                                             flip_horizontally: flip_horizontally
    outputs.sprites << entity.sprite
  end

  def new_game
    state.clock                   = 0
    state.game_over               = false
    state.gravity                 = -0.4
    state.drag                    = 0.15

    state.activation_time         = 90
    state.light_meter             = 600
    state.light_meter_queue       = 0

    state.midair_jump_frame_count = 9
    state.midair_jump_hold_for    = 6
    state.midair_jump_duration    = state.midair_jump_frame_count * state.midair_jump_hold_for

    # hard coded collision tiles
    state.tiles                   = [
      { impassable: true, x: 0, y: 0, w: 1280, h: 8, path: :pixel, r: 0, g: 0, b: 0 },
      { impassable: true, x: 0, y: 0, w: 8, h: 1500, path: :pixel, r: 0, g: 0, b: 0 },
      { impassable: true, x: 1280 - 8, y: 0, w: 8, h: 1500, path: :pixel, r: 0, g: 0, b: 0 },

      { x: 80 + 320 + 80,            y: 128, w: 320, h: 8, path: :pixel, r: 0, g: 0, b: 0 },
      { x: 80 + 320 + 80 + 320 + 80, y: 192, w: 320, h: 8, path: :pixel, r: 0, g: 0, b: 0 },

      { x: 160,                      y: 320, w: 400, h: 8, path: :pixel, r: 0, g: 0, b: 0 },
      { x: 160 + 400 + 160,          y: 400, w: 400, h: 8, path: :pixel, r: 0, g: 0, b: 0 },

      { x: 320,                      y: 600, w: 320, h: 8, path: :pixel, r: 0, g: 0, b: 0 },

      { x: 8, y: 500, w: 100, h: 8, path: :pixel, r: 0, g: 0, b: 0 },

      { x: 8, y: 60, w: 100, h: 8, path: :pixel, r: 0, g: 0, b: 0 },
    ]

    state.player                = new_entity
    state.player.jump_count     = 1
    state.player.jumped_at      = state.player.clock
    state.player.jumped_down_at = 0

    state.shadows   = []

    state.input_timeline = [
      { at: 0, k: :left_right, v: inputs.left_right },
      { at: 0, k: :space,      v: false },
      { at: 0, k: :down,       v: false },
    ]

    state.jitter_fade_out_render_queue   = []
    state.game_over_render_queue       ||= []

    state.light_crystal = new_light_crystal
  end

  def new_light_crystal
    r = { x: 124 + rand(1000), y: 135 + rand(500), w: 64, h: 64 }
    return new_light_crystal if tiles.any? { |t| t.intersect_rect? r }
    return new_light_crystal if (player.x - r.x).abs < 200
    r
  end

  def entity_active? entity
    return true unless entity.activate_at
    return entity.activate_at <= state.clock
  end

  def add_shadow!
    s = new_entity(from_entity: player)
    s.activate_at = state.clock + state.activation_time * (shadows.length + 1)
    s.spawn_countdown = state.activation_time
    shadows << s
  end

  def find_input_timeline at:, key:;
    state.input_timeline.find { |t| t.at <= at && t.k == key }.v
  end

  def new_entity from_entity: nil
    # these are all the properties of an entity
    # an optional from_entity can be passed in
    # for "cloning" an entity/setting an entities
    # starting state
    pe = state.new_entity(:body)
    pe.w                  = 96
    pe.h                  = 96
    pe.jump_power         = 12
    pe.y                  = 500
    pe.x                  = 640 - 8
    pe.initial_x          = pe.x
    pe.initial_y          = pe.y
    pe.dy                 = 0
    pe.dx                 = 0
    pe.jumped_down_at     = 0
    pe.jumped_at          = 0
    pe.jump_count         = 0
    pe.clock              = state.clock
    pe.orientation        = :right
    pe.action             = :falling
    pe.action_at          = state.clock
    pe.left_right         = 0
    if from_entity
      pe.w              = from_entity.w
      pe.h              = from_entity.h
      pe.jump_power     = from_entity.jump_power
      pe.x              = from_entity.x
      pe.y              = from_entity.y
      pe.initial_x      = from_entity.x
      pe.initial_y      = from_entity.y
      pe.dy             = from_entity.dy
      pe.dx             = from_entity.dx
      pe.jumped_down_at = from_entity.jumped_down_at
      pe.jumped_at      = from_entity.jumped_at
      pe.orientation    = from_entity.orientation
      pe.action         = from_entity.action
      pe.action_at      = from_entity.action_at
      pe.jump_count     = from_entity.jump_count
      pe.left_right     = from_entity.left_right
    end
    pe
  end

  def entity_on_platform? entity
    entity.action == :standing || entity.action == :running
  end

  def entity_action_complete? entity, action_duration
    entity.action_at.elapsed_time(entity.clock) + 1 >= action_duration
  end

  def entity_set_action! entity, action
    entity.action = action
    entity.action_at = entity.clock
    entity.last_standing_at = entity.clock if action == :standing
  end

  def player
    state.player
  end

  def shadows
    state.shadows
  end

  def tiles
    state.tiles
  end

  def find_tiles &block
    tiles.find_all(&block)
  end

  def find_collision tiles, target
    tiles.find { |t| t.rect.intersect_rect? target }
  end
end

def boot args
  # initialize the game on boot
  $game = Game.new
end

def tick args
  # tick the game class after setting .args
  # (which is provided by the engine)
  $game.args = args
  $game.tick
end

# debug function for resetting the game if requested
def reset args
  $game = Game.new
end

The Little Probe - main.rb link

# ./samples/99_genre_platformer/the_little_probe/app/main.rb
class FallingCircle
  attr_gtk

  def tick
    fiddle
    defaults
    render
    input
    calc
  end

  def fiddle
    state.gravity     = -0.02
    circle.radius     = 15
    circle.elasticity = 0.4
    camera.follow_speed = 0.4 * 0.4
  end

  def render
    render_stage_editor
    render_debug
    render_game
  end

  def defaults
    # if Kernel.tick_count == 0
    #   args.audio[:bg] = { input: "sounds/bg.ogg", looping: true }
    # end

    state.storyline ||= [
      { text: "<- -> to aim, hold space to charge",                            distance_gate: 0 },
      { text: "the little probe - by @amirrajan, made with DragonRuby Game Toolkit", distance_gate: 0 },
      { text: "mission control, this is sasha. landing on europa successful.", distance_gate: 0 },
      { text: "operation \"find earth 2.0\", initiated at 8-29-2036 14:00.",   distance_gate: 0 },
      { text: "jupiter's sure is beautiful...",   distance_gate: 4000 },
      { text: "hmm, it seems there's some kind of anomoly in the sky",   distance_gate: 7000 },
      { text: "dancing lights, i'll call them whisps.",   distance_gate: 8000 },
      { text: "#todo... look i ran out of time -_-",   distance_gate: 9000 },
      { text: "there's never enough time",   distance_gate: 9000 },
      { text: "the game jam was fun though ^_^",   distance_gate: 10000 },
    ]

    load_level force: Kernel.tick_count == 0
    state.line_mode            ||= :terrain

    state.sound_index          ||= 1
    circle.potential_lift      ||= 0
    circle.angle               ||= 90
    circle.check_point_at      ||= -1000
    circle.game_over_at        ||= -1000
    circle.x                   ||= -485
    circle.y                   ||= 12226
    circle.check_point_x       ||= circle.x
    circle.check_point_y       ||= circle.y
    circle.dy                  ||= 0
    circle.dx                  ||= 0
    circle.previous_dy         ||= 0
    circle.previous_dx         ||= 0
    circle.angle               ||= 0
    circle.after_images        ||= []
    circle.terrains_to_monitor ||= {}
    circle.impact_history      ||= []

    camera.x                   ||= 0
    camera.y                   ||= 0
    camera.target_x            ||= 0
    camera.target_y            ||= 0
    state.snaps                ||= { }
    state.snap_number            = 10

    args.state.storyline_x ||= -1000
    args.state.storyline_y ||= -1000
  end

  def render_game
    outputs.background_color = [0, 0, 0]
    outputs.sprites << { x: -circle.x + 1100,
                         y: -circle.y - 100,
                         w: 2416 * 4,
                         h: 3574 * 4,
                         path: 'sprites/jupiter.png' }
    outputs.sprites << { x: -circle.x,
                         y: -circle.y,
                         w: 2416 * 4,
                         h: 3574 * 4,
                         path: 'sprites/level.png' }
    outputs.sprites << state.whisp_queue
    render_aiming_retical
    render_circle
    render_notification
  end

  def render_notification
    toast_length = 500
    if circle.game_over_at.elapsed_time < toast_length
      label_text = "..."
    elsif circle.check_point_at.elapsed_time > toast_length
      args.state.current_storyline = nil
      return
    end
    if circle.check_point_at &&
       circle.check_point_at.elapsed_time == 1 &&
       !args.state.current_storyline
       if args.state.storyline.length > 0 && args.state.distance_traveled > args.state.storyline[0][:distance_gate]
         args.state.current_storyline = args.state.storyline.shift[:text]
         args.state.distance_traveled ||= 0
         args.state.storyline_x = circle.x
         args.state.storyline_y = circle.y
       end
      return unless args.state.current_storyline
    end
    label_text = args.state.current_storyline
    return unless label_text
    x = circle.x + camera.x
    y = circle.y + camera.y - 40
    w = 900
    h = 30
    outputs.primitives << { x: x - w.idiv(2), y: y - h, w: w, h: h, r: 255, g: 255, b: 255, a: 255, primitive_marker: :solid }
    outputs.primitives << { x: x - w.idiv(2), y: y - h, w: w, h: h, r: 0, g: 0, b: 0, a: 255, primitive_marker: :border }
    outputs.labels << { x: x, y: y - 4, text: label_text, size_enum: 1, alignment_enum: 1, r: 0, g: 0, b: 0, a: 255 }
  end

  def render_aiming_retical
    outputs.sprites << { x: state.camera.x + circle.x + circle.angle.vector_x(circle.potential_lift * 10) - 5,
                         y: state.camera.y + circle.y + circle.angle.vector_y(circle.potential_lift * 10) - 5,
                         w: 10, h: 10, path: 'sprites/circle-orange.png' }
    outputs.sprites << { x: state.camera.x + circle.x + circle.angle.vector_x(circle.radius * 3) - 5,
                         y: state.camera.y + circle.y + circle.angle.vector_y(circle.radius * 3) - 5,
                         w: 10, h: 10, path: 'sprites/circle-orange.png', angle: 0, a: 128 }
    if rand > 0.9
      outputs.sprites << { x: state.camera.x + circle.x + circle.angle.vector_x(circle.radius * 3) - 5,
                           y: state.camera.y + circle.y + circle.angle.vector_y(circle.radius * 3) - 5,
                           w: 10, h: 10, path: 'sprites/circle-white.png', angle: 0, a: 128 }
    end
  end

  def render_circle
    outputs.sprites << circle.after_images.map do |ai|
      ai.merge(x: ai.x + state.camera.x - circle.radius,
               y: ai.y + state.camera.y - circle.radius,
               w: circle.radius * 2,
               h: circle.radius * 2,
               path: 'sprites/circle-white.png')
    end

    outputs.sprites << { x: (circle.x - circle.radius) + state.camera.x,
                         y: (circle.y - circle.radius) + state.camera.y,
                         w: circle.radius * 2,
                         h: circle.radius * 2,
                         path: 'sprites/probe.png' }
  end

  def render_debug
    return unless state.debug_mode

    outputs.labels << { x: 10, y: 30, text: state.line_mode, size_enum: 0, alignment_enum: 0, r: 0, g: 0, b: 0 }
    outputs.labels << { x: 12, y: 32, text: state.line_mode, size_enum: 0, alignment_enum: 0, r: 255, g: 255, b: 255 }

    args.outputs.lines << trajectory(circle).to_line.to_hash.tap do |h|
      h[:x] += state.camera.x
      h[:y] += state.camera.y
      h[:x2] += state.camera.x
      h[:y2] += state.camera.y
    end

    outputs.primitives << state.terrain.find_all do |t|
      circle.x.between?(t.x - 640, t.x2 + 640) || circle.y.between?(t.y - 360, t.y2 + 360)
    end.map do |t|
      [
        t.to_line.merge(r: 0, g: 255, b: 0).then do |h|
          h.x  += state.camera.x
          h.y  += state.camera.y
          h.x2 += state.camera.x
          h.y2 += state.camera.y
          if circle.rect.intersect_rect? t[:rect]
            h[:r] = 255
            h[:g] = 0
          end
          h
        end,
        t[:rect].to_border.merge(r: 255, g: 0, b: 0).then do |h|
          h.x += state.camera.x
          h.y += state.camera.y
          h.b = 255 if line_near_rect? circle.rect, t
          h
        end
      ]
    end

    outputs.primitives << state.lava.find_all do |t|
      circle.x.between?(t.x - 640, t.x2 + 640) || circle.y.between?(t.y - 360, t.y2 + 360)
    end.map do |t|
      [
        t.to_line.merge(r: 0, g: 0, b: 255).then do |h|
          h.x  += state.camera.x
          h.y  += state.camera.y
          h.x2 += state.camera.x
          h.y2 += state.camera.y
          if circle.rect.intersect_rect? t[:rect]
            h[:r] = 255
            h[:b] = 0
          end
          h
        end,
        t[:rect].to_border.merge(r: 255, g: 0, b: 0).then do |h|
          h.x += state.camera.x
          h.y += state.camera.y
          h.b = 255 if line_near_rect? circle.rect, t
          h
        end
      ]
    end

    if state.god_mode
      border = circle.rect.merge(x: circle.rect.x + state.camera.x,
                                 y: circle.rect.y + state.camera.y,
                                 g: 255)
    else
      border = circle.rect.merge(x: circle.rect.x + state.camera.x,
                                 y: circle.rect.y + state.camera.y,
                                 b: 255)
    end

    outputs.borders << border

    overlapping ||= {}

    circle.impact_history.each do |h|
      label_mod = 300
      x = (h[:body][:x].-(150).idiv(label_mod)) * label_mod + camera.x
      y = (h[:body][:y].+(150).idiv(label_mod)) * label_mod + camera.y
      10.times do
        if overlapping[x] && overlapping[x][y]
          y -= 52
        else
          break
        end
      end

      overlapping[x] ||= {}
      overlapping[x][y] ||= true
      outputs.primitives << [x, y - 25, 300, 50, 0, 0, 0, 128].solid
      outputs.labels << [x + 10, y + 24, "dy: %.2f" % h[:body][:new_dy], -2, 0, 255, 255, 255]
      outputs.labels << [x + 10, y +  9, "dx: %.2f" % h[:body][:new_dx], -2, 0, 255, 255, 255]
      outputs.labels << [x + 10, y -  5, " ?: #{h[:body][:new_reason]}", -2, 0, 255, 255, 255]

      outputs.labels << [x + 100, y + 24, "angle: %.2f" % h[:impact][:angle], -2, 0, 255, 255, 255]
      outputs.labels << [x + 100, y + 9, "m(l): %.2f" % h[:terrain][:slope], -2, 0, 255, 255, 255]
      outputs.labels << [x + 100, y - 5, "m(c): %.2f" % h[:body][:slope], -2, 0, 255, 255, 255]

      outputs.labels << [x + 200, y + 24, "ray: #{h[:impact][:ray]}", -2, 0, 255, 255, 255]
      outputs.labels << [x + 200, y +  9, "nxt: #{h[:impact][:ray_next]}", -2, 0, 255, 255, 255]
      outputs.labels << [x + 200, y -  5, "typ: #{h[:impact][:type]}", -2, 0, 255, 255, 255]
    end

    if circle.floor
      outputs.labels << [circle.x + camera.x + 30, circle.y + camera.y + 100, "point: #{circle.floor_point.slice(:x, :y).values}", -2, 0]
      outputs.labels << [circle.x + camera.x + 31, circle.y + camera.y + 101, "point: #{circle.floor_point.slice(:x, :y).values}", -2, 0, 255, 255, 255]
      outputs.labels << [circle.x + camera.x + 30, circle.y + camera.y +  85, "circle: #{circle.as_hash.slice(:x, :y).values}", -2, 0]
      outputs.labels << [circle.x + camera.x + 31, circle.y + camera.y +  86, "circle: #{circle.as_hash.slice(:x, :y).values}", -2, 0, 255, 255, 255]
      outputs.labels << [circle.x + camera.x + 30, circle.y + camera.y +  70, "rel: #{circle.floor_relative_x} #{circle.floor_relative_y}", -2, 0]
      outputs.labels << [circle.x + camera.x + 31, circle.y + camera.y +  71, "rel: #{circle.floor_relative_x} #{circle.floor_relative_y}", -2, 0, 255, 255, 255]
    end
  end

  def render_stage_editor
    return unless state.god_mode
    return unless state.point_one
    args.lines << [state.point_one, inputs.mouse.point, 0, 255, 255]
  end

  def trajectory body
    { x: body.x + body.dx,
      y: body.y + body.dy,
      x2: body.x + body.dx * 1000,
      y2: body.y + body.dy * 1000,
      r: 0, g: 255, b: 255 }
  end

  def rect_for_line line
    if line.x > line.x2
      x  = line.x2
      y  = line.y2
      x2 = line.x
      y2 = line.y
    else
      x  = line.x
      y  = line.y
      x2 = line.x2
      y2 = line.y2
    end

    w = x2 - x
    h = y2 - y

    if h < 0
      y += h
      h = h.abs
    end

    if w < circle.radius
      x -= circle.radius
      w = circle.radius * 2
    end

    if h < circle.radius
      y -= circle.radius
      h = circle.radius * 2
    end

    { x: x, y: y, w: w, h: h }
  end

  def snap_to_grid x, y, snaps
    snap_number = 10
    x = x.to_i
    y = y.to_i

    x_floor = x.idiv(snap_number) * snap_number
    x_mod   = x % snap_number
    x_ceil  = (x.idiv(snap_number) + 1) * snap_number

    y_floor = y.idiv(snap_number) * snap_number
    y_mod   = y % snap_number
    y_ceil  = (y.idiv(snap_number) + 1) * snap_number

    if snaps[x_floor]
      x_result = x_floor
    elsif snaps[x_ceil]
      x_result = x_ceil
    elsif x_mod < snap_number.idiv(2)
      x_result = x_floor
    else
      x_result = x_ceil
    end

    snaps[x_result] ||= {}

    if snaps[x_result][y_floor]
      y_result = y_floor
    elsif snaps[x_result][y_ceil]
      y_result = y_ceil
    elsif y_mod < snap_number.idiv(2)
      y_result = y_floor
    else
      y_result = y_ceil
    end

    snaps[x_result][y_result] = true
    return [x_result, y_result]

  end

  def snap_line line
    x, y, x2, y2 = line
  end

  def string_to_line s
    x, y, x2, y2 = s.split(',').map(&:to_f)

    if x > x2
      x2, x = x, x2
      y2, y = y, y2
    end

    x, y = snap_to_grid x, y, state.snaps
    x2, y2 = snap_to_grid x2, y2, state.snaps
    [x, y, x2, y2].line.to_hash
  end

  def load_lines file
    return unless state.snaps
    data = gtk.read_file(file) || ""
    data.each_line
        .reject { |l| l.strip.length == 0 }
        .map { |l| string_to_line l }
        .map { |h| h.merge(rect: rect_for_line(h))  }
  end

  def load_terrain
    load_lines 'data/level.txt'
  end

  def load_lava
    load_lines 'data/level_lava.txt'
  end

  def load_level force: false
    if force
      state.snaps = {}
      state.terrain = load_terrain
      state.lava = load_lava
    else
      state.terrain ||= load_terrain
      state.lava ||= load_lava
    end
  end

  def save_lines lines, file
    s = lines.map do |l|
      "#{l.x},#{l.y},#{l.x2},#{l.y2}"
    end.join("\n")
    gtk.write_file(file, s)
  end

  def save_level
    save_lines(state.terrain, 'level.txt')
    save_lines(state.lava, 'level_lava.txt')
    load_level force: true
  end

  def line_near_rect? rect, terrain
    geometry.intersect_rect?(rect, terrain[:rect])
  end

  def point_within_line? point, line
    return false if !point
    return false if !line
    return true
  end

  def calc_impacts x, dx, y, dy, radius
    results = { }
    results[:x] = x
    results[:y] = y
    results[:dx] = x
    results[:dy] = y
    results[:point] = { x: x, y: y }
    results[:rect] = { x: x - radius, y: y - radius, w: radius * 2, h: radius * 2 }
    results[:trajectory] = trajectory(results)
    results[:impacts] = terrain.find_all { |t| t && (line_near_rect? results[:rect], t) }.map do |t|
      intersection = geometry.ray_intersect(results[:trajectory], t)
      {
        terrain: t,
        point: geometry.ray_intersect(results[:trajectory], t),
        type: :terrain
      }
    end

    results[:impacts] += lava.find_all { |t| line_near_rect? results[:rect], t }.map do |t|
      intersection = geometry.ray_intersect(results[:trajectory], t)
      {
        terrain: t,
        point: geometry.ray_intersect(results[:trajectory], t),
        type: :lava
      }
    end

    results
  end

  def calc_potential_impacts
    impact_results = calc_impacts circle.x, circle.dx, circle.y, circle.dy, circle.radius
    circle.rect = impact_results[:rect]
    circle.trajectory = impact_results[:trajectory]
    circle.impacts = impact_results[:impacts]
  end

  def calc_terrains_to_monitor
    return unless circle.impacts
    circle.impact = nil
    circle.impacts.each do |i|
      future_circle = { x: circle.x + circle.dx, y: circle.y + circle.dy }
      circle.terrains_to_monitor[i[:terrain]] ||= {
        ray_start: geometry.ray_test(future_circle, i[:terrain]),
      }

      circle.terrains_to_monitor[i[:terrain]][:ray_current] = geometry.ray_test(future_circle, i[:terrain])
      if circle.terrains_to_monitor[i[:terrain]][:ray_start] != circle.terrains_to_monitor[i[:terrain]][:ray_current]
        circle.impact = i
        circle.ray_current = circle.terrains_to_monitor[i[:terrain]][:ray_current]
      end
    end
  end

  def impact_result body, impact
    infinity_alias = 1000
    r = {
      body: {},
      terrain: {},
      impact: {}
    }

    r[:body][:line] = body.trajectory.dup
    r[:body][:slope] = geometry.line_slope(body.trajectory, replace_infinity: infinity_alias)
    r[:body][:slope_sign] = r[:body][:slope].sign
    r[:body][:x] = body.x
    r[:body][:y] = body.y
    r[:body][:dy] = body.dy
    r[:body][:dx] = body.dx

    r[:terrain][:line] = impact[:terrain].dup
    r[:terrain][:slope] = geometry.line_slope(impact[:terrain], replace_infinity: infinity_alias)
    r[:terrain][:slope_sign] = r[:terrain][:slope].sign

    r[:impact][:angle] = -geometry.angle_between_lines(body.trajectory, impact[:terrain], replace_infinity: infinity_alias)
    r[:impact][:point] = { x: impact[:point].x, y: impact[:point].y }
    r[:impact][:same_slope_sign] = r[:body][:slope_sign] == r[:terrain][:slope_sign]
    r[:impact][:ray] = body.ray_current
    r[:body][:new_on_floor] = body.on_floor
    r[:body][:new_floor] = r[:terrain][:line]

    if r[:impact][:angle].abs < 90 && r[:terrain][:slope].abs < 3
      play_sound
      r[:body][:new_dy] = r[:body][:dy] * circle.elasticity * -1
      r[:body][:new_dx] = r[:body][:dx] * circle.elasticity
      r[:impact][:type] = :horizontal
      r[:body][:new_reason] = "-"
    elsif r[:impact][:angle].abs < 90 && r[:terrain][:slope].abs > 3
      play_sound
      r[:body][:new_dy] = r[:body][:dy] * 1.1
      r[:body][:new_dx] = r[:body][:dx] * -circle.elasticity
      r[:impact][:type] = :vertical
      r[:body][:new_reason] = "|"
    else
      play_sound
      r[:body][:new_dx] = r[:body][:dx] * -circle.elasticity
      r[:body][:new_dy] = r[:body][:dy] * -circle.elasticity
      r[:impact][:type] = :slanted
      r[:body][:new_reason] = "/"
    end

    r[:impact][:energy] = r[:body][:new_dx].abs + r[:body][:new_dy].abs

    if r[:impact][:energy] <= 0.3 && r[:terrain][:slope].abs < 4
      r[:body][:new_dx] = 0
      r[:body][:new_dy] = 0
      r[:impact][:energy] = 0
      r[:body][:new_on_floor] = true if r[:impact][:point].y < body.y
      r[:body][:new_floor] = r[:terrain][:line]
      r[:body][:new_reason] = "0"
    end

    r[:impact][:ray_next] = geometry.ray_test({ x: r[:body][:x] - (r[:body][:dx] * 1.1) + r[:body][:new_dx],
                                                y: r[:body][:y] - (r[:body][:dy] * 1.1) + r[:body][:new_dy] + state.gravity },
                                              r[:terrain][:line])

    if r[:impact][:ray_next] == r[:impact][:ray]
      r[:body][:new_dx] *= -1
      r[:body][:new_dy] *= -1
      r[:body][:new_reason] = "clip"
    end

    r
  end

  def game_over!
    circle.x = circle.check_point_x
    circle.y = circle.check_point_y
    circle.dx = 0
    circle.dy = 0
    circle.game_over_at = Kernel.tick_count
  end

  def not_game_over!
    impact_history_entry = impact_result circle, circle.impact
    circle.impact_history << impact_history_entry
    circle.x -= circle.dx * 1.1
    circle.y -= circle.dy * 1.1
    circle.dx = impact_history_entry[:body][:new_dx]
    circle.dy = impact_history_entry[:body][:new_dy]
    circle.on_floor = impact_history_entry[:body][:new_on_floor]

    if circle.on_floor
      circle.check_point_at = Kernel.tick_count
      circle.check_point_x = circle.x
      circle.check_point_y = circle.y
    end

    circle.previous_floor = circle.floor || {}
    circle.floor = impact_history_entry[:body][:new_floor] || {}
    circle.floor_point = impact_history_entry[:impact][:point]
    if circle.floor.slice(:x, :y, :x2, :y2) != circle.previous_floor.slice(:x, :y, :x2, :y2)
      new_relative_x = if circle.dx > 0
                         :right
                       elsif circle.dx < 0
                         :left
                       else
                         nil
                       end

      new_relative_y = if circle.dy > 0
                         :above
                       elsif circle.dy < 0
                         :below
                       else
                         nil
                       end

      circle.floor_relative_x = new_relative_x
      circle.floor_relative_y = new_relative_y
    end

    circle.impact = nil
    circle.terrains_to_monitor.clear
  end

  def calc_physics
    if args.state.god_mode
      calc_potential_impacts
      calc_terrains_to_monitor
      return
    end

    if circle.y < -700
      game_over
      return
    end

    return if state.game_over
    return if circle.on_floor
    circle.previous_dy = circle.dy
    circle.previous_dx = circle.dx
    circle.x  += circle.dx
    circle.y  += circle.dy
    args.state.distance_traveled ||= 0
    args.state.distance_traveled += circle.dx.abs + circle.dy.abs
    circle.dy += state.gravity
    calc_potential_impacts
    calc_terrains_to_monitor
    return unless circle.impact
    if circle.impact && circle.impact[:type] == :lava
      game_over!
    else
      not_game_over!
    end
  end

  def input_god_mode
    state.debug_mode = !state.debug_mode if inputs.keyboard.key_down.forward_slash

    # toggle god mode
    if inputs.keyboard.key_down.g
      state.god_mode = !state.god_mode
      state.potential_lift = 0
      circle.floor = nil
      circle.floor_point = nil
      circle.floor_relative_x = nil
      circle.floor_relative_y = nil
      circle.impact = nil
      circle.terrains_to_monitor.clear
      return
    end

    return unless state.god_mode

    circle.x = circle.x.to_i
    circle.y = circle.y.to_i

    # move god circle
    if inputs.keyboard.left || inputs.keyboard.a
      circle.x -= 20
    elsif inputs.keyboard.right || inputs.keyboard.d || inputs.keyboard.f
      circle.x += 20
    end

    if inputs.keyboard.up || inputs.keyboard.w
      circle.y += 20
    elsif inputs.keyboard.down || inputs.keyboard.s
      circle.y -= 20
    end

    # delete terrain
    if inputs.keyboard.key_down.x
      calc_terrains_to_monitor
      state.terrain = state.terrain.reject do |t|
        t[:rect].intersect_rect? circle.rect
      end

      state.lava = state.lava.reject do |t|
        t[:rect].intersect_rect? circle.rect
      end

      calc_potential_impacts
      save_level
    end

    # change terrain type
    if inputs.keyboard.key_down.l
      if state.line_mode == :terrain
        state.line_mode = :lava
      else
        state.line_mode = :terrain
      end
    end

    if inputs.mouse.click && !state.point_one
      state.point_one = inputs.mouse.click.point
    elsif inputs.mouse.click && state.point_one
      l = [*state.point_one, *inputs.mouse.click.point]
      l = [l.x  - state.camera.x,
           l.y  - state.camera.y,
           l.x2 - state.camera.x,
           l.y2 - state.camera.y].line.to_hash
      l[:rect] = rect_for_line l
      if state.line_mode == :terrain
        state.terrain << l
      else
        state.lava << l
      end
      save_level
      next_x = inputs.mouse.click.point.x - 640
      next_y = inputs.mouse.click.point.y - 360
      circle.x += next_x
      circle.y += next_y
      state.point_one = nil
    elsif inputs.keyboard.one
      state.point_one = [circle.x + camera.x, circle.y+ camera.y]
    end

    # cancel chain lines
    if inputs.keyboard.key_down.nine || inputs.keyboard.key_down.escape || inputs.keyboard.key_up.six || inputs.keyboard.key_up.one
      state.point_one = nil
    end
  end

  def play_sound
    return if state.sound_debounce > 0
    state.sound_debounce = 5
    # outputs.sounds << "sounds/03#{"%02d" % state.sound_index}.wav"
    state.sound_index += 1
    if state.sound_index > 21
      state.sound_index = 1
    end
  end

  def input_game
    if inputs.keyboard.down || inputs.keyboard.space
      circle.potential_lift += 0.03
      circle.potential_lift = circle.potential_lift.lesser(10)
    elsif inputs.keyboard.key_up.down || inputs.keyboard.key_up.space
      play_sound
      circle.dy += circle.angle.vector_y circle.potential_lift
      circle.dx += circle.angle.vector_x circle.potential_lift

      if circle.on_floor
        if circle.floor_relative_y == :above
          circle.y += circle.potential_lift.abs * 2
        elsif circle.floor_relative_y == :below
          circle.y -= circle.potential_lift.abs * 2
        end
      end

      circle.on_floor = false
      circle.potential_lift = 0
      circle.terrains_to_monitor.clear
      circle.impact_history.clear
      circle.impact = nil
      calc_physics
    end

    # aim probe
    if inputs.keyboard.right || inputs.keyboard.a
      circle.angle -= 2
    elsif inputs.keyboard.left || inputs.keyboard.d
      circle.angle += 2
    end
  end

  def input
    input_god_mode
    input_game
  end

  def calc_camera
    state.camera.target_x = 640 - circle.x
    state.camera.target_y = 360 - circle.y
    xdiff = state.camera.target_x - state.camera.x
    ydiff = state.camera.target_y - state.camera.y
    state.camera.x += xdiff * camera.follow_speed
    state.camera.y += ydiff * camera.follow_speed
  end

  def calc
    state.sound_debounce ||= 0
    state.sound_debounce -= 1
    state.sound_debounce = 0 if state.sound_debounce < 0
    if state.god_mode
      circle.dy *= 0.1
      circle.dx *= 0.1
    end
    calc_camera
    state.whisp_queue ||= []
    if Kernel.tick_count.mod_zero?(4)
      state.whisp_queue << {
        x: -300,
        y: 1400 * rand,
        speed: 2.randomize(:ratio) + 3,
        w: 20,
        h: 20, path: 'sprites/whisp.png',
        a: 0,
        created_at: Kernel.tick_count,
        angle: 0,
        r: 100,
        g: 128 + 128 * rand,
        b: 128 + 128 * rand
      }
    end

    state.whisp_queue.each do |w|
      w.x += w[:speed] * 2
      w.x -= circle.dx * 0.3
      w.y -= w[:speed]
      w.y -= circle.dy * 0.3
      w.angle += w[:speed]
      w.a = w[:created_at].ease(30) * 255
    end

    state.whisp_queue = state.whisp_queue.reject { |w| w[:x] > 1280 }

    if Kernel.tick_count.mod_zero?(2) && (circle.dx != 0 || circle.dy != 0)
      circle.after_images << {
        x: circle.x,
        y: circle.y,
        w: circle.radius,
        h: circle.radius,
        a: 255,
        created_at: Kernel.tick_count
      }
    end

    circle.after_images.each do |ai|
      ai.a = ai[:created_at].ease(10, :flip) * 255
    end

    circle.after_images = circle.after_images.reject { |ai| ai[:created_at].elapsed_time > 10 }
    calc_physics
  end

  def circle
    state.circle
  end

  def camera
    state.camera
  end

  def terrain
    state.terrain
  end

  def lava
    state.lava
  end
end

# $gtk.reset

def tick args
  args.outputs.background_color = [0, 0, 0]
  if args.inputs.keyboard.r
    args.gtk.reset
    return
  end
  # uncomment the line below to slow down the game so you
  # can see each tick as it passes
  # args.gtk.slowmo! 30
  $game ||= FallingCircle.new
  $game.args = args
  $game.tick
end

def reset
  $game = nil
end

The Little Probe - Data - level.txt link

# ./samples/99_genre_platformer/the_little_probe/data/level.txt
640,8840,1180,8840
-60,10220,0,9960
-60,10220,0,10500
0,10500,0,10780
0,10780,40,10900
500,10920,760,10960
300,10560,820,10600
420,10320,700,10300
820,10600,1500,10600
1500,10600,1940,10600
1940,10600,2380,10580
2380,10580,2800,10620
2240,11080,2480,11020
2000,11120,2240,11080
1760,11180,2000,11120
1620,11180,1760,11180
1500,11220,1620,11180
1180,11280,1340,11220
1040,11240,1180,11280
840,11280,1040,11240
640,11280,840,11280
500,11220,640,11280
420,11140,500,11220
240,11100,420,11140
100,11120,240,11100
0,11180,100,11120
-160,11220,0,11180
-260,11240,-160,11220
1340,11220,1500,11220
960,13300,1280,13060
1280,13060,1540,12860
1540,12860,1820,12700
1820,12700,2080,12520
2080,12520,2240,12400
2240,12400,2240,12240
2240,12240,2400,12080
2400,12080,2560,11920
2560,11920,2640,11740
2640,11740,2740,11580
2740,11580,2800,11400
2800,11400,2800,11240
2740,11140,2800,11240
2700,11040,2740,11140
2700,11040,2740,10960
2740,10960,2740,10920
2700,10900,2740,10920
2380,10900,2700,10900
2040,10920,2380,10900
1720,10940,2040,10920
1380,11000,1720,10940
1180,10980,1380,11000
900,10980,1180,10980
760,10960,900,10980
240,10960,500,10920
40,10900,240,10960
0,9700,0,9960
-60,9500,0,9700
-60,9420,-60,9500
-60,9420,-60,9340
-60,9340,-60,9280
-60,9120,-60,9280
-60,8940,-60,9120
-60,8940,-60,8780
-60,8780,0,8700
0,8700,40,8680
40,8680,240,8700
240,8700,360,8780
360,8780,640,8840
1420,8400,1540,8480
1540,8480,1680,8500
1680,8500,1940,8460
1180,8840,1280,8880
1280,8880,1340,8860
1340,8860,1720,8860
1720,8860,1820,8920
1820,8920,1820,9140
1820,9140,1820,9280
1820,9460,1820,9280
1760,9480,1820,9460
1640,9480,1760,9480
1540,9500,1640,9480
1340,9500,1540,9500
1100,9500,1340,9500
1040,9540,1100,9500
960,9540,1040,9540
300,9420,360,9460
240,9440,300,9420
180,9600,240,9440
120,9660,180,9600
100,9820,120,9660
100,9820,120,9860
120,9860,140,9900
140,9900,140,10000
140,10440,180,10540
100,10080,140,10000
100,10080,140,10100
140,10100,140,10440
180,10540,300,10560
2140,9560,2140,9640
2140,9720,2140,9640
1880,9780,2140,9720
1720,9780,1880,9780
1620,9740,1720,9780
1500,9780,1620,9740
1380,9780,1500,9780
1340,9820,1380,9780
1200,9820,1340,9820
1100,9780,1200,9820
900,9780,1100,9780
820,9720,900,9780
540,9720,820,9720
360,9840,540,9720
360,9840,360,9960
360,9960,360,10080
360,10140,360,10080
360,10140,360,10240
360,10240,420,10320
700,10300,820,10280
820,10280,820,10280
820,10280,900,10320
900,10320,1040,10300
1040,10300,1200,10320
1200,10320,1380,10280
1380,10280,1500,10300
1500,10300,1760,10300
2800,10620,2840,10600
2840,10600,2900,10600
2900,10600,3000,10620
3000,10620,3080,10620
3080,10620,3140,10600
3140,10540,3140,10600
3140,10540,3140,10460
3140,10460,3140,10360
3140,10360,3140,10260
3140,10260,3140,10140
3140,10140,3140,10000
3140,10000,3140,9860
3140,9860,3160,9720
3160,9720,3160,9580
3160,9580,3160,9440
3160,9300,3160,9440
3160,9300,3160,9140
3160,9140,3160,8980
3160,8980,3160,8820
3160,8820,3160,8680
3160,8680,3160,8520
1760,10300,1880,10300
660,9500,960,9540
640,9460,660,9500
360,9460,640,9460
-480,10760,-440,10880
-480,11020,-440,10880
-480,11160,-260,11240
-480,11020,-480,11160
-600,11420,-380,11320
-380,11320,-200,11340
-200,11340,0,11340
0,11340,180,11340
960,13420,960,13300
960,13420,960,13520
960,13520,1000,13560
1000,13560,1040,13540
1040,13540,1200,13440
1200,13440,1380,13380
1380,13380,1620,13300
1620,13300,1820,13220
1820,13220,2000,13200
2000,13200,2240,13200
2240,13200,2440,13160
2440,13160,2640,13040
-480,10760,-440,10620
-440,10620,-360,10560
-380,10460,-360,10560
-380,10460,-360,10300
-380,10140,-360,10300
-380,10140,-380,10040
-380,9880,-380,10040
-380,9720,-380,9880
-380,9720,-380,9540
-380,9360,-380,9540
-380,9180,-380,9360
-380,9180,-380,9000
-380,8840,-380,9000
-380,8840,-380,8760
-380,8760,-380,8620
-380,8620,-380,8520
-380,8520,-360,8400
-360,8400,-100,8400
-100,8400,-60,8420
-60,8420,240,8440
240,8440,240,8380
240,8380,500,8440
500,8440,760,8460
760,8460,1000,8400
1000,8400,1180,8420
1180,8420,1420,8400
1940,8460,2140,8420
2140,8420,2200,8520
2200,8680,2200,8520
2140,8840,2200,8680
2140,8840,2140,9020
2140,9100,2140,9020
2140,9200,2140,9100
2140,9200,2200,9320
2200,9320,2200,9440
2140,9560,2200,9440
1880,10300,2200,10280
2200,10280,2480,10260
2480,10260,2700,10240
2700,10240,2840,10180
2840,10180,2900,10060
2900,9860,2900,10060
2900,9640,2900,9860
2900,9640,2900,9500
2900,9460,2900,9500
2740,9460,2900,9460
2700,9460,2740,9460
2700,9360,2700,9460
2700,9320,2700,9360
2600,9320,2700,9320
2600,9260,2600,9320
2600,9200,2600,9260
2480,9120,2600,9200
2440,9080,2480,9120
2380,9080,2440,9080
2320,9060,2380,9080
2320,8860,2320,9060
2320,8860,2380,8840
2380,8840,2480,8860
2480,8860,2600,8840
2600,8840,2740,8840
2740,8840,2840,8800
2840,8800,2900,8700
2900,8600,2900,8700
2900,8480,2900,8600
2900,8380,2900,8480
2900,8380,2900,8260
2900,8260,2900,8140
2900,8140,2900,8020
2900,8020,2900,7900
2900,7820,2900,7900
2900,7820,2900,7740
2900,7660,2900,7740
2900,7560,2900,7660
2900,7460,2900,7560
2900,7460,2900,7360
2900,7260,2900,7360
2840,7160,2900,7260
2800,7080,2840,7160
2700,7100,2800,7080
2560,7120,2700,7100
2400,7100,2560,7120
2320,7100,2400,7100
2140,7100,2320,7100
2040,7080,2140,7100
1940,7080,2040,7080
1820,7140,1940,7080
1680,7140,1820,7140
1540,7140,1680,7140
1420,7220,1540,7140
1280,7220,1380,7220
1140,7200,1280,7220
1000,7220,1140,7200
760,7280,900,7320
540,7220,760,7280
300,7180,540,7220
180,7120,180,7160
40,7140,180,7120
-60,7160,40,7140
-200,7120,-60,7160
180,7160,300,7180
-260,7060,-200,7120
-260,6980,-260,7060
-260,6880,-260,6980
-260,6880,-260,6820
-260,6820,-200,6760
-200,6760,-100,6740
-100,6740,-60,6740
-60,6740,40,6740
40,6740,300,6800
300,6800,420,6760
420,6760,500,6740
500,6740,540,6760
540,6760,540,6760
540,6760,640,6780
640,6660,640,6780
580,6580,640,6660
580,6440,580,6580
580,6440,640,6320
640,6320,640,6180
580,6080,640,6180
580,6080,640,5960
640,5960,640,5840
640,5840,640,5700
640,5700,660,5560
660,5560,660,5440
660,5440,660,5300
660,5140,660,5300
660,5140,660,5000
660,5000,660,4880
660,4880,820,4860
820,4860,1000,4840
1000,4840,1100,4860
1100,4860,1280,4860
1280,4860,1420,4840
1420,4840,1580,4860
1580,4860,1720,4820
1720,4820,1880,4860
1880,4860,2000,4840
2000,4840,2140,4840
2140,4840,2320,4860
2320,4860,2440,4880
2440,4880,2600,4880
2600,4880,2800,4880
2800,4880,2900,4880
2900,4880,2900,4820
2900,4740,2900,4820
2800,4700,2900,4740
2520,4680,2800,4700
2240,4660,2520,4680
1940,4620,2240,4660
1820,4580,1940,4620
1820,4500,1820,4580
1820,4500,1880,4420
1880,4420,2000,4420
2000,4420,2200,4420
2200,4420,2400,4440
2400,4440,2600,4440
2600,4440,2840,4440
2840,4440,2900,4400
2740,4260,2900,4280
2600,4240,2740,4260
2480,4280,2600,4240
2320,4240,2480,4280
2140,4220,2320,4240
1940,4220,2140,4220
1880,4160,1940,4220
1880,4160,1880,4080
1880,4080,2040,4040
2040,4040,2240,4060
2240,4060,2400,4040
2400,4040,2600,4060
2600,4060,2740,4020
2740,4020,2840,3940
2840,3780,2840,3940
2740,3660,2840,3780
2700,3680,2740,3660
2520,3700,2700,3680
2380,3700,2520,3700
2200,3720,2380,3700
2040,3720,2200,3720
1880,3700,2040,3720
1820,3680,1880,3700
1760,3600,1820,3680
1760,3600,1820,3480
1820,3480,1880,3440
1880,3440,1960,3460
1960,3460,2140,3460
2140,3460,2380,3460
2380,3460,2640,3440
2640,3440,2900,3380
2840,3280,2900,3380
2840,3280,2900,3200
2900,3200,2900,3140
2840,3020,2900,3140
2800,2960,2840,3020
2700,3000,2800,2960
2600,2980,2700,3000
2380,3000,2600,2980
2140,3000,2380,3000
1880,3000,2140,3000
1720,3040,1880,3000
1640,2960,1720,3040
1500,2940,1640,2960
1340,3000,1500,2940
1240,3000,1340,3000
1140,3020,1240,3000
1040,3000,1140,3020
960,2960,1040,3000
900,2960,960,2960
840,2840,900,2960
700,2820,840,2840
540,2820,700,2820
420,2820,540,2820
180,2800,420,2820
60,2780,180,2800
-60,2800,60,2780
-160,2760,-60,2800
-260,2740,-160,2760
-300,2640,-260,2740
-360,2560,-300,2640
-380,2460,-360,2560
-380,2460,-300,2380
-300,2300,-300,2380
-300,2300,-300,2220
-300,2100,-300,2220
-300,2100,-300,2040
-300,2040,-160,2040
-160,2040,-60,2040
-60,2040,60,2040
60,2040,180,2040
180,2040,360,2040
360,2040,540,2040
540,2040,700,2080
660,2160,700,2080
660,2160,700,2260
660,2380,700,2260
500,2340,660,2380
360,2340,500,2340
240,2340,360,2340
40,2320,240,2340
-60,2320,40,2320
-100,2380,-60,2320
-100,2380,-100,2460
-100,2460,-100,2540
-100,2540,0,2560
0,2560,140,2600
140,2600,300,2600
300,2600,460,2600
460,2600,640,2600
640,2600,760,2580
760,2580,820,2560
820,2560,820,2500
820,2500,820,2400
820,2400,840,2320
840,2320,840,2240
820,2120,840,2240
820,2020,820,2120
820,1900,820,2020
760,1840,820,1900
640,1840,760,1840
500,1840,640,1840
300,1860,420,1880
180,1840,300,1860
420,1880,500,1840
0,1840,180,1840
-60,1860,0,1840
-160,1840,-60,1860
-200,1800,-160,1840
-260,1760,-200,1800
-260,1680,-260,1760
-260,1620,-260,1680
-260,1540,-260,1620
-260,1540,-260,1460
-300,1420,-260,1460
-300,1420,-300,1340
-300,1340,-260,1260
-260,1260,-260,1160
-260,1060,-260,1160
-260,1060,-260,960
-260,880,-260,960
-260,880,-260,780
-260,780,-260,680
-300,580,-260,680
-300,580,-300,480
-300,480,-260,400
-300,320,-260,400
-300,320,-300,240
-300,240,-200,220
-200,220,-200,160
-200,160,-100,140
-100,140,0,120
0,120,60,120
60,120,180,120
180,120,300,120
300,120,420,140
420,140,580,180
580,180,760,180
760,180,900,180
960,180,1100,180
1100,180,1340,200
1340,200,1580,200
1580,200,1720,180
1720,180,2000,140
2000,140,2240,140
2240,140,2480,140
2520,140,2800,160
2800,160,3000,160
3000,160,3140,160
3140,260,3140,160
3140,260,3140,380
3080,500,3140,380
3080,620,3080,500
3080,620,3080,740
3080,740,3080,840
3080,960,3080,840
3080,1080,3080,960
3080,1080,3080,1200
3080,1200,3080,1340
3080,1340,3080,1460
3080,1580,3080,1460
3080,1700,3080,1580
3080,1700,3080,1760
3080,1760,3200,1760
3200,1760,3320,1760
3320,1760,3520,1760
3520,1760,3680,1740
3680,1740,3780,1700
3780,1700,3840,1620
3840,1620,3840,1520
3840,1520,3840,1420
3840,1320,3840,1420
3840,1120,3840,1320
3840,1120,3840,940
3840,940,3840,760
3780,600,3840,760
3780,600,3780,440
3780,320,3780,440
3780,320,3780,160
3780,60,3780,160
3780,60,4020,60
4020,60,4260,40
4260,40,4500,40
4500,40,4740,40
4740,40,4840,20
4840,20,4880,80
4880,80,5080,40
5080,40,5280,20
5280,20,5500,0
5500,0,5720,0
5720,0,5940,60
5940,60,6240,60
6240,60,6540,20
6540,20,6840,20
6840,20,7040,0
7040,0,7140,0
7140,0,7400,20
7400,20,7680,0
7680,0,7940,0
7940,0,8200,-20
8200,-20,8360,20
8360,20,8560,-40
8560,-40,8760,0
8760,0,8880,40
8880,120,8880,40
8840,220,8840,120
8620,240,8840,220
8420,260,8620,240
8200,280,8420,260
7940,280,8200,280
7760,240,7940,280
7560,220,7760,240
7360,280,7560,220
7140,260,7360,280
6940,240,7140,260
6720,220,6940,240
6480,220,6720,220
6360,300,6480,220
6240,300,6360,300
6200,500,6240,300
6200,500,6360,540
6360,540,6540,520
6540,520,6720,480
6720,480,6880,460
6880,460,7080,500
7080,500,7320,500
7320,500,7680,500
7680,620,7680,500
7520,640,7680,620
7360,640,7520,640
7200,640,7360,640
7040,660,7200,640
6880,720,7040,660
6720,700,6880,720
6540,700,6720,700
6420,760,6540,700
6280,740,6420,760
6240,760,6280,740
6200,920,6240,760
6200,920,6360,960
6360,960,6540,960
6540,960,6720,960
6720,960,6760,980
6760,980,6880,940
6880,940,7080,940
7080,940,7280,940
7280,940,7520,920
7520,920,7760,900
7760,900,7980,860
7980,860,8100,880
8100,880,8280,900
8280,900,8500,820
8500,820,8700,820
8700,820,8760,840
8760,960,8760,840
8700,1040,8760,960
8560,1060,8700,1040
8460,1080,8560,1060
8360,1040,8460,1080
8280,1080,8360,1040
8160,1120,8280,1080
8040,1120,8160,1120
7940,1100,8040,1120
7800,1120,7940,1100
7680,1120,7800,1120
7520,1100,7680,1120
7360,1100,7520,1100
7200,1120,7360,1100
7040,1180,7200,1120
6880,1160,7040,1180
6720,1160,6880,1160
6540,1160,6720,1160
6360,1160,6540,1160
6200,1160,6360,1160
6040,1220,6200,1160
6040,1220,6040,1400
6040,1400,6200,1440
6200,1440,6320,1440
6320,1440,6440,1440
6600,1440,6760,1440
6760,1440,6940,1420
6440,1440,6600,1440
6940,1420,7280,1400
7280,1400,7560,1400
7560,1400,7760,1400
7760,1400,7940,1360
7940,1360,8100,1380
8100,1380,8280,1340
8280,1340,8460,1320
8660,1300,8760,1360
8460,1320,8660,1300
8760,1360,8800,1500
8800,1660,8800,1500
8800,1660,8800,1820
8700,1840,8800,1820
8620,1860,8700,1840
8560,1800,8620,1860
8560,1800,8620,1680
8500,1640,8620,1680
8420,1680,8500,1640
8280,1680,8420,1680
8160,1680,8280,1680
7900,1680,8160,1680
7680,1680,7900,1680
7400,1660,7680,1680
7140,1680,7400,1660
6880,1640,7140,1680
6040,1820,6320,1780
5900,1840,6040,1820
6640,1700,6880,1640
6320,1780,6640,1700
5840,2040,5900,1840
5840,2040,5840,2220
5840,2220,5840,2320
5840,2460,5840,2320
5840,2560,5840,2460
5840,2560,5960,2620
5960,2620,6200,2620
6200,2620,6380,2600
6380,2600,6600,2580
6600,2580,6800,2600
6800,2600,7040,2580
7040,2580,7280,2580
7280,2580,7480,2560
7760,2540,7980,2520
7980,2520,8160,2500
7480,2560,7760,2540
8160,2500,8160,2420
8160,2420,8160,2320
8160,2180,8160,2320
7980,2160,8160,2180
7800,2180,7980,2160
7600,2200,7800,2180
7400,2200,7600,2200
6960,2200,7200,2200
7200,2200,7400,2200
6720,2200,6960,2200
6540,2180,6720,2200
6320,2200,6540,2180
6240,2160,6320,2200
6240,2160,6240,2040
6240,2040,6240,1940
6240,1940,6440,1940
6440,1940,6720,1940
6720,1940,6940,1920
7520,1920,7760,1920
6940,1920,7280,1920
7280,1920,7520,1920
7760,1920,8100,1900
8100,1900,8420,1900
8420,1900,8460,1940
8460,2120,8460,1940
8460,2280,8460,2120
8460,2280,8560,2420
8560,2420,8660,2380
8660,2380,8800,2340
8800,2340,8840,2400
8840,2520,8840,2400
8800,2620,8840,2520
8800,2740,8800,2620
8800,2860,8800,2740
8800,2940,8800,2860
8760,2980,8800,2940
8660,2980,8760,2980
8620,2960,8660,2980
8560,2880,8620,2960
8560,2880,8560,2780
8500,2740,8560,2780
8420,2760,8500,2740
8420,2840,8420,2760
8420,2840,8420,2940
8420,3040,8420,2940
8420,3160,8420,3040
8420,3280,8420,3380
8420,3280,8420,3160
8420,3380,8620,3460
8620,3460,8760,3460
8760,3460,8840,3400
8840,3400,8960,3400
8960,3400,9000,3500
9000,3700,9000,3500
9000,3900,9000,3700
9000,4080,9000,3900
9000,4280,9000,4080
9000,4500,9000,4280
9000,4620,9000,4500
9000,4780,9000,4620
9000,4780,9000,4960
9000,5120,9000,4960
9000,5120,9000,5300
8960,5460,9000,5300
8920,5620,8960,5460
8920,5620,8920,5800
8920,5800,8920,5960
8920,5960,8920,6120
8920,6120,8960,6300
8960,6300,8960,6480
8960,6660,8960,6480
8960,6860,8960,6660
8960,7040,8960,6860
8920,7420,8920,7220
8920,7420,8960,7620
8960,7620,8960,7800
8960,7800,8960,8000
8960,8000,8960,8180
8960,8180,8960,8380
8960,8580,8960,8380
8920,8800,8960,8580
8880,9000,8920,8800
8840,9180,8880,9000
8800,9220,8840,9180
8800,9220,8840,9340
8760,9380,8840,9340
8560,9340,8760,9380
8360,9360,8560,9340
8160,9360,8360,9360
8040,9340,8160,9360
7860,9360,8040,9340
7680,9360,7860,9360
7520,9360,7680,9360
7420,9260,7520,9360
7400,9080,7420,9260
7400,9080,7420,8860
7420,8860,7440,8720
7440,8720,7480,8660
7480,8660,7520,8540
7520,8540,7600,8460
7600,8460,7800,8480
7800,8480,8040,8480
8040,8480,8280,8480
8280,8480,8500,8460
8500,8460,8620,8440
8620,8440,8660,8340
8660,8340,8660,8220
8660,8220,8700,8080
8700,8080,8700,7920
8700,7920,8700,7760
8700,7760,8700,7620
8700,7480,8700,7620
8700,7480,8700,7320
8700,7160,8700,7320
8920,7220,8960,7040
8660,7040,8700,7160
8660,7040,8700,6880
8660,6700,8700,6880
8660,6700,8700,6580
8700,6460,8700,6580
8700,6460,8700,6320
8700,6160,8700,6320
8700,6160,8760,6020
8760,6020,8760,5860
8760,5860,8760,5700
8760,5700,8760,5540
8760,5540,8760,5360
8760,5360,8760,5180
8760,5000,8760,5180
8700,4820,8760,5000
8560,4740,8700,4820
8420,4700,8560,4740
8280,4700,8420,4700
8100,4700,8280,4700
7980,4700,8100,4700
7820,4740,7980,4700
7800,4920,7820,4740
7800,4920,7900,4960
7900,4960,8060,4980
8060,4980,8220,5000
8220,5000,8420,5040
8420,5040,8460,5120
8460,5180,8460,5120
8360,5200,8460,5180
8360,5280,8360,5200
8160,5300,8360,5280
8040,5260,8160,5300
7860,5220,8040,5260
7720,5160,7860,5220
7640,5120,7720,5160
7480,5120,7640,5120
7240,5120,7480,5120
7000,5120,7240,5120
6800,5160,7000,5120
6640,5220,6800,5160
6600,5360,6640,5220
6600,5460,6600,5360
6480,5520,6600,5460
6240,5540,6480,5520
5980,5540,6240,5540
5740,5540,5980,5540
5500,5520,5740,5540
5400,5520,5500,5520
5280,5540,5400,5520
5080,5540,5280,5540
4940,5540,5080,5540
4760,5540,4940,5540
4600,5540,4760,5540
4440,5560,4600,5540
4040,5580,4120,5520
4260,5540,4440,5560
4120,5520,4260,5540
4020,5720,4040,5580
4020,5840,4020,5720
4020,5840,4080,5940
4080,5940,4120,6040
4120,6040,4200,6080
4200,6080,4340,6080
4340,6080,4500,6060
4500,6060,4700,6060
4700,6060,4880,6060
4880,6060,5080,6060
5080,6060,5280,6080
5280,6080,5440,6100
5440,6100,5660,6100
5660,6100,5900,6080
5900,6080,6120,6080
6120,6080,6360,6080
6360,6080,6480,6100
6480,6100,6540,6060
6540,6060,6720,6060
6720,6060,6940,6060
6940,6060,7140,6060
7400,6060,7600,6060
7140,6060,7400,6060
7600,6060,7800,6060
7800,6060,7860,6080
7860,6080,8060,6080
8060,6080,8220,6080
8220,6080,8320,6140
8320,6140,8360,6300
8320,6460,8360,6300
8320,6620,8320,6460
8320,6800,8320,6620
8320,6960,8320,6800
8320,6960,8360,7120
8320,7280,8360,7120
8320,7440,8320,7280
8320,7600,8320,7440
8100,7580,8220,7600
8220,7600,8320,7600
7900,7560,8100,7580
7680,7560,7900,7560
7480,7580,7680,7560
7280,7580,7480,7580
7080,7580,7280,7580
7000,7600,7080,7580
6880,7600,7000,7600
6800,7580,6880,7600
6640,7580,6800,7580
6540,7580,6640,7580
6380,7600,6540,7580
6280,7620,6380,7600
6240,7700,6280,7620
6240,7700,6240,7800
6240,7840,6240,7800
6080,7840,6240,7840
5960,7820,6080,7840
5660,7840,5800,7840
5500,7800,5660,7840
5440,7700,5500,7800
5800,7840,5960,7820
5440,7540,5440,7700
5440,7440,5440,7540
5440,7320,5440,7440
5400,7320,5440,7320
5340,7400,5400,7320
5340,7400,5340,7500
5340,7600,5340,7500
5340,7600,5340,7720
5340,7720,5340,7860
5340,7860,5340,7960
5340,7960,5440,8020
5440,8020,5560,8020
5560,8020,5720,8040
5720,8040,5900,8060
5900,8060,6080,8060
6080,8060,6240,8060
6720,8040,6840,8060
6240,8060,6480,8040
6480,8040,6720,8040
6840,8060,6940,8060
6940,8060,7080,8120
7080,8120,7140,8180
7140,8460,7140,8320
7140,8620,7140,8460
7140,8620,7140,8740
7140,8860,7140,8740
7140,8960,7140,8860
7140,8960,7200,9080
7140,9200,7200,9080
7140,9200,7200,9320
7200,9320,7200,9460
7200,9760,7200,9900
7200,9620,7200,9460
7200,9620,7200,9760
7200,9900,7200,10060
7200,10220,7200,10060
7200,10360,7200,10220
7140,10400,7200,10360
6880,10400,7140,10400
6640,10360,6880,10400
6420,10360,6640,10360
6160,10380,6420,10360
5940,10340,6160,10380
5720,10320,5940,10340
5500,10340,5720,10320
5280,10300,5500,10340
5080,10300,5280,10300
4840,10280,5080,10300
4700,10280,4840,10280
4540,10280,4700,10280
4360,10280,4540,10280
4200,10300,4360,10280
4040,10380,4200,10300
4020,10500,4040,10380
3980,10640,4020,10500
3980,10640,3980,10760
3980,10760,4020,10920
4020,10920,4080,11000
4080,11000,4340,11020
4340,11020,4600,11060
4600,11060,4840,11040
4840,11040,4880,10960
4880,10740,4880,10960
4880,10740,4880,10600
4880,10600,5080,10560
5080,10560,5340,10620
5340,10620,5660,10620
5660,10620,6040,10600
6040,10600,6120,10620
6120,10620,6240,10720
6240,10720,6420,10740
6420,10740,6640,10760
6640,10760,6880,10780
7140,10780,7400,10780
6880,10780,7140,10780
7400,10780,7680,10780
7680,10780,8100,10760
8100,10760,8460,10740
8460,10740,8700,10760
8800,10840,8800,10980
8700,10760,8800,10840
8760,11200,8800,10980
8760,11200,8760,11380
8760,11380,8800,11560
8760,11680,8800,11560
8760,11760,8760,11680
8760,11760,8760,11920
8760,11920,8800,12080
8800,12200,8800,12080
8700,12240,8800,12200
8560,12220,8700,12240
8360,12220,8560,12220
8160,12240,8360,12220
7720,12220,7980,12220
7980,12220,8160,12240
7400,12200,7720,12220
7200,12180,7400,12200
7000,12160,7200,12180
6800,12160,7000,12160
6280,12140,6380,12180
6120,12180,6280,12140
6540,12180,6800,12160
6380,12180,6540,12180
5900,12200,6120,12180
5620,12180,5900,12200
5340,12120,5620,12180
5140,12100,5340,12120
4980,12120,5140,12100
4840,12120,4980,12120
4700,12200,4840,12120
4700,12380,4700,12200
4740,12480,4940,12520
4700,12380,4740,12480
4940,12520,5160,12560
5160,12560,5340,12600
5340,12600,5400,12600
5400,12600,5500,12600
5500,12600,5620,12600
5620,12600,5720,12560
5720,12560,5800,12440
5800,12440,5900,12380
5900,12380,6120,12420
6120,12420,6380,12440
6380,12440,6600,12460
6720,12460,6840,12520
6840,12520,6960,12520
6600,12460,6720,12460
6960,12520,7040,12500
7040,12500,7140,12440
7200,12440,7360,12500
7360,12500,7600,12560
7600,12560,7860,12600
7860,12600,8060,12500
8100,12500,8200,12340
8200,12340,8360,12360
8360,12360,8560,12400
8560,12400,8660,12420
8660,12420,8840,12400
8840,12400,9000,12360
9000,12360,9000,12360
2900,4400,2900,4280
900,7320,1000,7220
2640,13040,2900,12920
2900,12920,3160,12840
3480,12760,3780,12620
3780,12620,4020,12460
4300,12360,4440,12260
4020,12460,4300,12360
3160,12840,3480,12760
4440,12080,4440,12260
4440,12080,4440,11880
4440,11880,4440,11720
4440,11720,4600,11720
4600,11720,4760,11740
4760,11740,4980,11760
4980,11760,5160,11760
5160,11760,5340,11780
6000,11860,6120,11820
5340,11780,5620,11820
5620,11820,6000,11860
6120,11820,6360,11820
6360,11820,6640,11860
6940,11920,7240,11940
7240,11940,7520,11960
7520,11960,7860,11960
7860,11960,8100,11920
8100,11920,8420,11940
8420,11940,8460,11960
8460,11960,8500,11860
8460,11760,8500,11860
8320,11720,8460,11760
8160,11720,8320,11720
7940,11720,8160,11720
7720,11700,7940,11720
7520,11680,7720,11700
7320,11680,7520,11680
7200,11620,7320,11680
7200,11620,7200,11500
7200,11500,7280,11440
7280,11440,7420,11440
7420,11440,7600,11440
7600,11440,7980,11460
7980,11460,8160,11460
8160,11460,8360,11460
8360,11460,8460,11400
8420,11060,8500,11200
8280,11040,8420,11060
8100,11060,8280,11040
8460,11400,8500,11200
7800,11060,8100,11060
7520,11060,7800,11060
7240,11060,7520,11060
6940,11040,7240,11060
6640,11000,6940,11040
6420,10980,6640,11000
6360,11060,6420,10980
6360,11180,6360,11060
6200,11280,6360,11180
5960,11300,6200,11280
5720,11280,5960,11300
5500,11280,5720,11280
4940,11300,5200,11280
4660,11260,4940,11300
4440,11280,4660,11260
4260,11280,4440,11280
4220,11220,4260,11280
4080,11280,4220,11220
3980,11420,4080,11280
3980,11420,4040,11620
4040,11620,4040,11820
3980,11960,4040,11820
3840,12000,3980,11960
3720,11940,3840,12000
3680,11800,3720,11940
3680,11580,3680,11800
3680,11360,3680,11580
3680,11360,3680,11260
3680,11080,3680,11260
3680,11080,3680,10880
3680,10700,3680,10880
3680,10700,3680,10620
3680,10480,3680,10620
3680,10480,3680,10300
3680,10300,3680,10100
3680,10100,3680,9940
3680,9940,3720,9860
3720,9860,3920,9900
3920,9900,4220,9880
4980,9940,5340,9960
4220,9880,4540,9900
4540,9900,4980,9940
5340,9960,5620,9960
5620,9960,5900,9960
5900,9960,6160,10000
6160,10000,6480,10000
6480,10000,6720,10000
6720,10000,6880,9860
6880,9860,6880,9520
6880,9520,6940,9340
6940,9120,6940,9340
6940,9120,6940,8920
6940,8700,6940,8920
6880,8500,6940,8700
6880,8320,6880,8500
7140,8320,7140,8180
6760,8260,6880,8320
6540,8240,6760,8260
6420,8180,6540,8240
6280,8240,6420,8180
6160,8300,6280,8240
6120,8400,6160,8300
6080,8520,6120,8400
5840,8480,6080,8520
5620,8500,5840,8480
5500,8500,5620,8500
5340,8560,5500,8500
5160,8540,5340,8560
4620,8520,4880,8520
4360,8480,4620,8520
4880,8520,5160,8540
4140,8440,4360,8480
3920,8460,4140,8440
3720,8380,3920,8460
3680,8160,3720,8380
3680,8160,3720,7940
3720,7720,3720,7940
3680,7580,3720,7720
3680,7580,3720,7440
3720,7440,3720,7300
3720,7160,3720,7300
3720,7160,3720,7020
3720,7020,3780,6900
3780,6900,4080,6940
4080,6940,4340,6980
4340,6980,4600,6980
4600,6980,4880,6980
4880,6980,5160,6980
5160,6980,5400,7000
5400,7000,5560,7020
5560,7020,5660,7080
5660,7080,5660,7280
5660,7280,5660,7440
5660,7440,5740,7520
5740,7520,5740,7600
5740,7600,5900,7600
5900,7600,6040,7540
6040,7540,6040,7320
6040,7320,6120,7200
6120,7200,6120,7040
6120,7040,6240,7000
6240,7000,6480,7060
6480,7060,6800,7060
6800,7060,7080,7080
7080,7080,7320,7100
7940,7100,7980,6920
7860,6860,7980,6920
7640,6860,7860,6860
7400,6840,7640,6860
7320,7100,7560,7120
7560,7120,7760,7120
7760,7120,7940,7100
7200,6820,7400,6840
7040,6820,7200,6820
6600,6840,6840,6840
6380,6800,6600,6840
6120,6800,6380,6800
5900,6840,6120,6800
5620,6820,5900,6840
5400,6800,5620,6820
5140,6800,5400,6800
4880,6780,5140,6800
4600,6760,4880,6780
4340,6760,4600,6760
4080,6760,4340,6760
3840,6740,4080,6760
3680,6720,3840,6740
3680,6720,3680,6560
3680,6560,3720,6400
3720,6400,3720,6200
3720,6200,3780,6000
3720,5780,3780,6000
3720,5580,3720,5780
3720,5360,3720,5580
3720,5360,3840,5240
3840,5240,4200,5260
4200,5260,4600,5280
4600,5280,4880,5280
4880,5280,5140,5200
5140,5200,5220,5100
5220,5100,5280,4900
5280,4900,5340,4840
5340,4840,5720,4880
6120,4880,6480,4860
6880,4840,7200,4860
6480,4860,6880,4840
7200,4860,7320,4860
7320,4860,7360,4740
7360,4600,7440,4520
7360,4600,7360,4740
7440,4520,7640,4520
7640,4520,7800,4480
7800,4480,7800,4280
7800,4280,7800,4040
7800,4040,7800,3780
7800,3560,7800,3780
7800,3560,7860,3440
7860,3440,8060,3460
8060,3460,8160,3340
8160,3340,8160,3140
8160,3140,8160,2960
8000,2900,8160,2960
7860,2900,8000,2900
7640,2940,7860,2900
7400,2980,7640,2940
7100,2980,7400,2980
6840,3000,7100,2980
5620,2980,5840,2980
5840,2980,6500,3000
6500,3000,6840,3000
5560,2780,5620,2980
5560,2780,5560,2580
5560,2580,5560,2380
5560,2140,5560,2380
5560,2140,5560,1900
5560,1900,5620,1660
5620,1660,5660,1460
5660,1460,5660,1300
5500,1260,5660,1300
5340,1260,5500,1260
4600,1220,4840,1240
4440,1220,4600,1220
4440,1080,4440,1220
4440,1080,4600,1020
5080,1260,5340,1260
4840,1240,5080,1260
4600,1020,4940,1020
4940,1020,5220,1020
5220,1020,5560,960
5560,960,5660,860
5660,740,5660,860
5280,740,5660,740
4940,780,5280,740
4660,760,4940,780
4500,700,4660,760
4500,520,4500,700
4500,520,4700,460
4700,460,5080,440
5440,420,5740,420
5080,440,5440,420
5740,420,5840,360
5800,280,5840,360
5560,280,5800,280
4980,300,5280,320
4360,320,4660,300
4200,360,4360,320
5280,320,5560,280
4660,300,4980,300
4140,480,4200,360
4140,480,4140,640
4140,640,4200,780
4200,780,4200,980
4200,980,4220,1180
4220,1400,4220,1180
4220,1400,4260,1540
4260,1540,4500,1540
4500,1540,4700,1520
4700,1520,4980,1540
5280,1560,5400,1560
4980,1540,5280,1560
5400,1560,5400,1700
5400,1780,5400,1700
5340,1900,5400,1780
5340,2020,5340,1900
5340,2220,5340,2020
5340,2220,5340,2420
5340,2420,5340,2520
5080,2600,5220,2580
5220,2580,5340,2520
4900,2580,5080,2600
4700,2540,4900,2580
4500,2540,4700,2540
4220,2580,4340,2540
4200,2700,4220,2580
4340,2540,4500,2540
3980,2740,4200,2700
3840,2740,3980,2740
3780,2640,3840,2740
3780,2640,3780,2460
3780,2280,3780,2460
3620,2020,3780,2100
3780,2280,3780,2100
3360,2040,3620,2020
3080,2040,3360,2040
2840,2020,3080,2040
2740,1940,2840,2020
2740,1940,2800,1800
2800,1640,2800,1800
2800,1640,2800,1460
2800,1300,2800,1460
2700,1180,2800,1300
2480,1140,2700,1180
1580,1200,1720,1200
2240,1180,2480,1140
1960,1180,2240,1180
1720,1200,1960,1180
1500,1320,1580,1200
1500,1440,1500,1320
1500,1440,1760,1480
1760,1480,1940,1480
1940,1480,2140,1500
2140,1500,2320,1520
2400,1560,2400,1700
2280,1820,2380,1780
2320,1520,2400,1560
2380,1780,2400,1700
2080,1840,2280,1820
1720,1820,2080,1840
1420,1800,1720,1820
1280,1800,1420,1800
1240,1720,1280,1800
1240,1720,1240,1600
1240,1600,1280,1480
1280,1340,1280,1480
1180,1280,1280,1340
1000,1280,1180,1280
760,1280,1000,1280
360,1240,540,1260
180,1220,360,1240
540,1260,760,1280
180,1080,180,1220
180,1080,180,1000
180,1000,360,940
360,940,540,960
540,960,820,980
1100,980,1200,920
820,980,1100,980
6640,11860,6940,11920
5200,11280,5500,11280
4120,7330,4120,7230
4120,7230,4660,7250
4660,7250,4940,7250
4940,7250,5050,7340
5010,7400,5050,7340
4680,7380,5010,7400
4380,7370,4680,7380
4120,7330,4360,7370
4120,7670,4120,7760
4120,7670,4280,7650
4280,7650,4540,7660
4550,7660,4820,7680
4820,7680,4900,7730
4880,7800,4900,7730
4620,7820,4880,7800
4360,7790,4620,7820
4120,7760,4360,7790
6840,6840,7040,6820
5720,4880,6120,4880
1200,920,1340,810
1340,810,1520,790
1520,790,1770,800
2400,790,2600,750
2600,750,2640,520
2520,470,2640,520
2140,470,2520,470
1760,800,2090,800
2080,800,2400,790
1760,450,2140,470
1420,450,1760,450
1180,440,1420,450
900,480,1180,440
640,450,900,480
360,440,620,450
120,430,360,440
0,520,120,430
-20,780,0,520
-20,780,-20,1020
-20,1020,-20,1150
-20,1150,0,1300
0,1470,60,1530
0,1300,0,1470
60,1530,360,1530
360,1530,660,1520
660,1520,980,1520
980,1520,1040,1520
1040,1520,1070,1560
1070,1770,1070,1560
1070,1770,1100,2010
1070,2230,1100,2010
1070,2240,1180,2340
1180,2340,1580,2340
1580,2340,1940,2350
1940,2350,2440,2350
2440,2350,2560,2380
2560,2380,2600,2540
2810,2640,3140,2680
2600,2540,2810,2640
3140,2680,3230,2780
3230,2780,3260,2970
3230,3220,3260,2970
3200,3470,3230,3220
3200,3480,3210,3760
3210,3760,3210,4040
3200,4040,3230,4310
3210,4530,3230,4310
3210,4530,3230,4730
3230,4960,3230,4730
3230,4960,3260,5190
3170,5330,3260,5190
2920,5330,3170,5330
2660,5360,2920,5330
2420,5330,2660,5360
2200,5280,2400,5330
2020,5280,2200,5280
1840,5260,2020,5280
1660,5280,1840,5260
1500,5300,1660,5280
1360,5270,1500,5300
1200,5290,1340,5270
1070,5400,1200,5290
1040,5630,1070,5400
1000,5900,1040,5630
980,6170,1000,5900
980,6280,980,6170
980,6540,980,6280
980,6540,1040,6720
1040,6720,1360,6730
1360,6730,1760,6710
2110,6720,2420,6730
1760,6710,2110,6720
2420,6730,2640,6720
2640,6720,2970,6720
2970,6720,3160,6700
3160,6700,3240,6710
3240,6710,3260,6890
3260,7020,3260,6890
3230,7180,3260,7020
3230,7350,3230,7180
3210,7510,3230,7350
3210,7510,3210,7690
3210,7870,3210,7690
3210,7870,3210,7980
3200,8120,3210,7980
3200,8330,3200,8120
3160,8520,3200,8330
2460,11100,2480,11020
2200,11180,2460,11100
1260,11350,1600,11320
600,11430,930,11400
180,11340,620,11430
1600,11320,1910,11280
1910,11280,2200,11180
923.0029599285435,11398.99893503157,1264.002959928544,11351.99893503157

The Little Probe - Data - level_lava.txt link

# ./samples/99_genre_platformer/the_little_probe/data/level_lava.txt
100,10740,500,10780
500,10780,960,10760
960,10760,1340,10760
1380,10760,1820,10780
1820,10780,2240,10780
2280,10780,2740,10740
2740,10740,3000,10780
3000,10780,3140,11020
-520,8820,-480,9160
-520,8480,-520,8820
-520,8480,-480,8180
-480,8180,-200,8120
-200,8120,100,8220
100,8220,420,8240
420,8240,760,8260
760,8260,1140,8280
1140,8280,1500,8200
1500,8200,1880,8240
1880,8240,2240,8260
2240,8260,2320,8480
2320,8480,2380,8680
2240,8860,2380,8680
2240,9080,2240,8860
2240,9080,2320,9260
2320,9260,2480,9440
2480,9440,2600,9640
2480,9840,2600,9640
2400,10020,2480,9840
2240,10080,2400,10020
1960,10080,2240,10080
1720,10080,1960,10080
1460,10080,1720,10080
1180,10080,1420,10080
900,10080,1180,10080
640,10080,900,10080
640,10080,640,9900
60,10520,100,10740
40,10240,60,10520
40,10240,40,9960
40,9960,40,9680
40,9680,40,9360
40,9360,60,9080
60,9080,100,8860
100,8860,460,9040
460,9040,760,9220
760,9220,1140,9220
1140,9220,1720,9200
-660,11580,-600,11420
-660,11800,-660,11580
-660,12000,-660,11800
-660,12000,-600,12220
-600,12220,-600,12440
-600,12440,-600,12640
-600,11240,-260,11280
-260,11280,100,11240
9000,12360,9020,12400
9020,12620,9020,12400
9020,12840,9020,12620
9020,13060,9020,12840
9020,13060,9020,13240
9020,13240,9020,13420
9020,13420,9020,13600
9020,13600,9020,13780
8880,13900,9020,13780
8560,13800,8880,13900
8220,13780,8560,13800
7860,13760,8220,13780
7640,13780,7860,13760
7360,13800,7640,13780
7100,13800,7360,13800
6540,13760,6800,13780
6800,13780,7100,13800
6280,13760,6540,13760
5760,13760,6280,13760
5220,13780,5760,13760
4700,13760,5220,13780
4200,13740,4700,13760
3680,13720,4200,13740
3140,13700,3680,13720
2600,13680,3140,13700
2040,13940,2600,13680
1640,13940,2040,13940
1200,13960,1640,13940
840,14000,1200,13960
300,13960,840,14000
-200,13900,300,13960
-600,12840,-600,12640
-600,13140,-600,12840
-600,13140,-600,13420
-600,13700,-600,13420
-600,13700,-600,13820
-600,13820,-200,13900
-600,11240,-560,11000
-560,11000,-480,10840
-520,10660,-480,10840
-520,10660,-520,10480
-520,10480,-520,10300
-520,10260,-480,10080
-480,9880,-440,10060
-520,9680,-480,9880
-520,9680,-480,9400
-480,9400,-480,9160
1820,9880,2140,9800
1540,9880,1820,9880
1200,9920,1500,9880
900,9880,1200,9920
640,9900,840,9880
2380,8760,2800,8760
2800,8760,2840,8660
2840,8660,2840,8420
2840,8160,2840,8420
2800,7900,2840,8160
2800,7900,2800,7720
2800,7540,2800,7720
2800,7540,2800,7360
2700,7220,2800,7360
2400,7220,2700,7220
2080,7240,2400,7220
1760,7320,2080,7240
1380,7360,1720,7320
1040,7400,1340,7360
640,7400,1000,7420
300,7380,640,7400
0,7300,240,7380
-300,7180,-60,7300
-380,6860,-360,7180
-380,6880,-360,6700
-360,6700,-260,6540
-260,6540,0,6520
0,6520,240,6640
240,6640,460,6640
460,6640,500,6480
500,6260,500,6480
460,6060,500,6260
460,5860,460,6060
460,5860,500,5640
500,5640,540,5440
540,5440,580,5220
580,5220,580,5000
580,4960,580,4740
580,4740,960,4700
960,4700,1140,4760
1140,4760,1420,4740
1420,4740,1720,4700
1720,4700,2000,4740
2000,4740,2380,4760
2380,4760,2700,4800
1720,4600,1760,4300
1760,4300,2200,4340
2200,4340,2560,4340
2560,4340,2740,4340
2160,12580,2440,12400
1820,12840,2160,12580
1500,13080,1820,12840
1140,13340,1500,13080
1140,13340,1580,13220
2110,13080,2520,13000
2520,13000,2900,12800
1580,13220,2110,13080
2900,12800,3200,12680
3200,12680,3440,12640
3440,12640,3720,12460
3720,12460,4040,12320
4040,12320,4360,12200
4360,11940,4380,12180
4360,11700,4360,11940
4360,11700,4540,11500
4540,11500,4880,11540
6000,11660,6280,11640
5440,11600,5720,11610
5720,11610,6000,11660
6280,11640,6760,11720
6760,11720,7060,11780
7060,11780,7360,11810
7360,11810,7640,11840
7640,11840,8000,11830
8000,11830,8320,11850
8320,11850,8390,11800
8330,11760,8390,11800
8160,11760,8330,11760
7910,11750,8160,11760
7660,11740,7900,11750
7400,11730,7660,11740
7160,11680,7400,11730
7080,11570,7160,11680
7080,11570,7100,11350
7100,11350,7440,11280
7440,11280,7940,11280
7960,11280,8360,11280
5840,11540,6650,11170
4880,11540,5440,11600
3410,11830,3420,11300
3410,11260,3520,10920
3520,10590,3520,10920
3520,10590,3540,10260
3520,9900,3540,10240
3520,9900,3640,9590
3640,9570,4120,9590
4140,9590,4600,9680
4620,9680,5030,9730
5120,9750,5520,9800
5620,9820,6080,9800
6130,9810,6580,9820
6640,9820,6800,9700
6780,9400,6800,9700
6780,9400,6840,9140
6820,8860,6840,9120
6780,8600,6820,8830
6720,8350,6780,8570
6480,8340,6720,8320
6260,8400,6480,8340
6050,8580,6240,8400
5760,8630,6040,8590
5520,8690,5740,8630
5120,8690,5450,8700
4570,8670,5080,8690
4020,8610,4540,8670
3540,8480,4020,8610
3520,8230,3520,8480
3520,7930,3520,8230
3520,7930,3540,7630
3480,7320,3540,7610
3480,7280,3500,7010
3500,6980,3680,6850
3680,6850,4220,6840
4230,6840,4760,6850
4780,6850,5310,6860
5310,6860,5720,6940
5720,6940,5880,7250
5880,7250,5900,7520
100,11240,440,11300
440,11300,760,11330
1480,11280,1840,11230
2200,11130,2360,11090
1840,11230,2200,11130

Genre Rpg Narrative link

Choose Your Own Adventure - decision.rb link

# ./samples/99_genre_rpg_narrative/choose_your_own_adventure/app/decision.rb
# Hey there! Welcome to Four Decisions. Here is how you
# create your decision tree. Remove =being and =end from the text to
# enable the game (just save the file). Change stuff and see what happens!

def game
  {
    starting_decision: :stormy_night,
    decisions: {
      stormy_night: {
        description: 'It was a dark and stormy night. (storyline located in decision.rb)',
        option_one: {
          description: 'Go to sleep.',
          decision: :nap
        },
        option_two: {
          description: 'Watch a movie.',
          decision: :movie
        },
        option_three: {
          description: 'Go outside.',
          decision: :go_outside
        },
        option_four: {
          description: 'Get a snack.',
          decision: :get_a_snack
        }
      },
      nap: {
        description: 'You took a nap. The end.',
        option_one: {
          description: 'Start over.',
          decision: :stormy_night
        }
      }
    }
  }
end

Choose Your Own Adventure - main.rb link

# ./samples/99_genre_rpg_narrative/choose_your_own_adventure/app/main.rb
=begin

 Reminders:

 - Hashes: Collection of unique keys and their corresponding values. The values can be found
   using their keys.

   In this sample app, the decisions needed for the game are stored in a hash. In fact, the
   decision.rb file contains hashes inside of other hashes!

   Each option is a key in the first hash, but also contains a hash (description and
   decision being its keys) as its value.
   Go into the decision.rb file and take a look before diving into the code below.

 - args.outputs.labels: An array. The values generate a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGNMENT, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.md.

 - args.keyboard.key_down.KEY: Determines if a key is in the down state or pressed down.
   For more information about the keyboard, go to mygame/documentation/06-keyboard.md.

 - String interpolation: uses #{} syntax; everything between the #{ and the } is evaluated
   as Ruby code, and the placeholder is replaced with its corresponding value or result.

=end

# This sample app provides users with a story and multiple decisions that they can choose to make.
# Users can make a decision using their keyboard, and the story will move forward based on user choices.

# The decisions available to users are stored in the decision.rb file.
# We must have access to it for the game to function properly.
GAME_FILE = 'app/decision.rb' # found in app folder

require GAME_FILE # require used to load another file, import class/method definitions

# Instructions are given using labels to users if they have not yet set up their story in the decision.rb file.
# Otherwise, the game is run.
def tick args
  if !args.state.loaded && !respond_to?(:game) # if game is not loaded and not responding to game symbol's method
    args.labels << [640, 370, 'Hey there! Welcome to Four Decisions.', 0, 1] # a welcome label is shown
    args.labels << [640, 340, 'Go to the file called decision.rb and tell me your story.', 0, 1]
  elsif respond_to?(:game) # otherwise, if responds to game
    args.state.loaded = true
    tick_game args # calls tick_game method, runs game
  end

  if Kernel.tick_count.mod_zero? 60 # update every 60 frames
    t = args.gtk.ffi_file.mtime GAME_FILE # mtime returns modification time for named file
    if t != args.state.mtime
      args.state.mtime = t
      require GAME_FILE # require used to load file
      args.state.game_definition = nil # game definition and decision are empty
      args.state.decision_id = nil
    end
  end
end

# Runs methods needed for game to function properly
# Creates a rectangular border around the screen
def tick_game args
  defaults args
  args.borders << args.grid.rect
  render_decision args
  process_inputs args
end

# Sets default values and uses decision.rb file to define game and decision_id
# variable using the starting decision
def defaults args
  args.state.game_definition ||= game
  args.state.decision_id ||= args.state.game_definition[:starting_decision]
end

# Outputs the possible decision descriptions the user can choose onto the screen
# as well as what key to press on their keyboard to make their decision
def render_decision args
  decision = current_decision args
  # text is either the value of decision's description key or warning that no description exists
  args.labels << [640, 360, decision[:description] || "No definition found for #{args.state.decision_id}. Please update decision.rb.", 0, 1] # uses string interpolation

  # All decisions are stored in a hash
  # The descriptions output onto the screen are the values for the description keys of the hash.
  if decision[:option_one]
    args.labels << [10, 360, decision[:option_one][:description], 0, 0] # option one's description label
    args.labels << [10, 335, "(Press 'left' on the keyboard to select this decision)", -5, 0] # label of what key to press to select the decision
  end

  if decision[:option_two]
    args.labels << [1270, 360, decision[:option_two][:description], 0, 2] # option two's description
    args.labels << [1270, 335, "(Press 'right' on the keyboard to select this decision)", -5, 2]
  end

  if decision[:option_three]
    args.labels << [640, 45, decision[:option_three][:description], 0, 1] # option three's description
    args.labels << [640, 20, "(Press 'down' on the keyboard to select this decision)", -5, 1]
  end

  if decision[:option_four]
    args.labels << [640, 700, decision[:option_four][:description], 0, 1] # option four's description
    args.labels << [640, 675, "(Press 'up' on the keyboard to select this decision)", -5, 1]
  end
end

# Uses keyboard input from the user to make a decision
# Assigns the decision as the value of the decision_id variable
def process_inputs args
  decision = current_decision args # calls current_decision method

  if args.keyboard.key_down.left! && decision[:option_one] # if left key pressed and option one exists
    args.state.decision_id = decision[:option_one][:decision] # value of option one's decision hash key is set to decision_id
  end

  if args.keyboard.key_down.right! && decision[:option_two] # if right key pressed and option two exists
    args.state.decision_id = decision[:option_two][:decision] # value of option two's decision hash key is set to decision_id
  end

  if args.keyboard.key_down.down! && decision[:option_three] # if down key pressed and option three exists
    args.state.decision_id = decision[:option_three][:decision] # value of option three's decision hash key is set to decision_id
  end

  if args.keyboard.key_down.up! && decision[:option_four] # if up key pressed and option four exists
    args.state.decision_id = decision[:option_four][:decision] # value of option four's decision hash key is set to decision_id
  end
end

# Uses decision_id's value to keep track of current decision being made
def current_decision args
  args.state.game_definition[:decisions][args.state.decision_id] || {} # either has value or is empty
end

# Resets the game.
$gtk.reset

Return Of Serenity - lowrez_simulator.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/lowrez_simulator.rb
###################################################################################
# YOU CAN PLAY AROUND WITH THE CODE BELOW, BUT USE CAUTION AS THIS IS WHAT EMULATES
# THE 64x64 CANVAS.
###################################################################################

TINY_RESOLUTION       = 64
TINY_SCALE            = 720.fdiv(TINY_RESOLUTION + 5)
CENTER_OFFSET         = 10
EMULATED_FONT_SIZE    = 20
EMULATED_FONT_X_ZERO  = 0
EMULATED_FONT_Y_ZERO  = 46

def tick args
  sprites = []
  labels = []
  borders = []
  solids = []
  mouse = emulate_lowrez_mouse args
  args.state.show_gridlines = false
  lowrez_tick args, sprites, labels, borders, solids, mouse
  render_gridlines_if_needed args
  render_mouse_crosshairs args, mouse
  emulate_lowrez_scene args, sprites, labels, borders, solids, mouse
end

def emulate_lowrez_mouse args
  args.state.new_entity_strict(:lowrez_mouse) do |m|
    m.x = args.mouse.x.idiv(TINY_SCALE) - CENTER_OFFSET.idiv(TINY_SCALE) - 1
    m.y = args.mouse.y.idiv(TINY_SCALE)
    if args.mouse.click
      m.click = [
        args.mouse.click.point.x.idiv(TINY_SCALE) - CENTER_OFFSET.idiv(TINY_SCALE) - 1,
        args.mouse.click.point.y.idiv(TINY_SCALE)
      ]
      m.down = m.click
    else
      m.click = nil
      m.down = nil
    end

    if args.mouse.up
      m.up = [
        args.mouse.up.point.x.idiv(TINY_SCALE) - CENTER_OFFSET.idiv(TINY_SCALE) - 1,
        args.mouse.up.point.y.idiv(TINY_SCALE)
      ]
    else
      m.up = nil
    end
  end
end

def render_mouse_crosshairs args, mouse
  return unless args.state.show_gridlines
  args.labels << [10, 25, "mouse: #{mouse.x} #{mouse.y}", 255, 255, 255]
end

def emulate_lowrez_scene args, sprites, labels, borders, solids, mouse
  args.render_target(:lowrez).solids  << [0, 0, 1280, 720]
  args.render_target(:lowrez).sprites << sprites
  args.render_target(:lowrez).borders << borders
  args.render_target(:lowrez).solids  << solids
  args.outputs.primitives << labels.map do |l|
    as_label = l.label
    l.text.each_char.each_with_index.map do |char, i|
      [CENTER_OFFSET + EMULATED_FONT_X_ZERO + (as_label.x * TINY_SCALE) + i * 5 * TINY_SCALE,
       EMULATED_FONT_Y_ZERO + (as_label.y * TINY_SCALE), char,
       EMULATED_FONT_SIZE, 0, as_label.r, as_label.g, as_label.b, as_label.a, 'fonts/dragonruby-gtk-4x4.ttf'].label
    end
  end

  args.sprites    << [CENTER_OFFSET, 0, 1280 * TINY_SCALE, 720 * TINY_SCALE, :lowrez]
end

def render_gridlines_if_needed args
  if args.state.show_gridlines && args.static_lines.length == 0
    args.static_lines << 65.map do |i|
      [
        [CENTER_OFFSET + i * TINY_SCALE + 1,  0,
         CENTER_OFFSET + i * TINY_SCALE + 1,  720,                128, 128, 128],
        [CENTER_OFFSET + i * TINY_SCALE,      0,
         CENTER_OFFSET + i * TINY_SCALE,      720,                128, 128, 128],
        [CENTER_OFFSET,                       0 + i * TINY_SCALE,
         CENTER_OFFSET + 720,                 0 + i * TINY_SCALE, 128, 128, 128],
        [CENTER_OFFSET,                       1 + i * TINY_SCALE,
         CENTER_OFFSET + 720,                 1 + i * TINY_SCALE, 128, 128, 128]
      ]
    end
  elsif !args.state.show_gridlines
    args.static_lines.clear
  end
end

Return Of Serenity - main.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/main.rb
require 'app/require.rb'

def defaults args
  args.outputs.background_color = [0, 0, 0]
  args.state.last_story_line_text ||= ""
  args.state.scene_history ||= []
  args.state.storyline_history ||= []
  args.state.word_delay ||= 8
  if Kernel.tick_count == 0
    args.gtk.stop_music
    args.outputs.sounds << 'sounds/static-loop.ogg'
  end

  if args.state.last_story_line_text
    lines = args.state
                .last_story_line_text
                .gsub("-", "")
                .gsub("~", "")
                .wrapped_lines(50)

    args.outputs.labels << lines.map_with_index { |l, i| [690, 200 - (i * 25), l, 1, 0, 255, 255, 255] }
  elsif args.state.storyline_history[-1]
    lines = args.state
                .storyline_history[-1]
                .gsub("-", "")
                .gsub("~", "")
                .wrapped_lines(50)

    args.outputs.labels << lines.map_with_index { |l, i| [690, 200 - (i * 25), l, 1, 0, 255, 255, 255] }
  end

  return if args.state.current_scene
  set_scene(args, day_one_beginning(args))
end

def inputs_move_player args
  if args.state.scene_changed_at.elapsed_time > 5
    if args.keyboard.down  || args.keyboard.s || args.keyboard.j
      args.state.player.y -= 0.25
    elsif args.keyboard.up || args.keyboard.w || args.keyboard.k
      args.state.player.y += 0.25
    end

    if args.keyboard.left     || args.keyboard.a  || args.keyboard.h
      args.state.player.x -= 0.25
    elsif args.keyboard.right || args.keyboard.d  || args.keyboard.l
      args.state.player.x += 0.25
    end

    args.state.player.y = 60 if args.state.player.y > 63
    args.state.player.y =  0 if args.state.player.y < -3
    args.state.player.x = 60 if args.state.player.x > 63
    args.state.player.x =  0 if args.state.player.x < -3
  end
end

def null_or_empty? ary
  return true unless ary
  return true if ary.length == 0
  return false
end

def calc_storyline_hotspot args
  hotspots = args.state.storylines.find_all do |hs|
    args.state.player.inside_rect?(hs.shift_rect(-2, 0))
  end

  if !null_or_empty?(hotspots) && !args.state.inside_storyline_hotspot
    _, _, _, _, storyline = hotspots.first
    queue_storyline_text(args, storyline)
    args.state.inside_storyline_hotspot = true
  elsif null_or_empty?(hotspots)
    args.state.inside_storyline_hotspot = false

    args.state.storyline_queue_empty_at ||= Kernel.tick_count
    args.state.is_storyline_dialog_active = false
    args.state.scene_storyline_queue.clear
  end
end

def calc_scenes args
  hotspots = args.state.scenes.find_all do |hs|
    args.state.player.inside_rect?(hs.shift_rect(-2, 0))
  end

  if !null_or_empty?(hotspots) && !args.state.inside_scene_hotspot
    _, _, _, _, scene_method_or_hash = hotspots.first
    if scene_method_or_hash.is_a? Symbol
      set_scene(args, send(scene_method_or_hash, args))
      args.state.last_hotspot_scene = scene_method_or_hash
      args.state.scene_history << scene_method_or_hash
    else
      set_scene(args, scene_method_or_hash)
    end
    args.state.inside_scene_hotspot = true
  elsif null_or_empty?(hotspots)
    args.state.inside_scene_hotspot = false
  end
end

def null_or_whitespace? word
  return true if !word
  return true if word.strip.length == 0
  return false
end

def calc_storyline_presentation args
  return unless Kernel.tick_count > args.state.next_storyline
  return unless args.state.scene_storyline_queue
  next_storyline = args.state.scene_storyline_queue.shift
  if null_or_whitespace? next_storyline
    args.state.storyline_queue_empty_at ||= Kernel.tick_count
    args.state.is_storyline_dialog_active = false
    return
  end
  args.state.storyline_to_show = next_storyline
  args.state.is_storyline_dialog_active = true
  args.state.storyline_queue_empty_at = nil
  if next_storyline.end_with?(".") || next_storyline.end_with?("!") || next_storyline.end_with?("?") || next_storyline.end_with?("\"")
    args.state.next_storyline += 60
  elsif next_storyline.end_with?(",")
    args.state.next_storyline += 50
  elsif next_storyline.end_with?(":")
    args.state.next_storyline += 60
  else
    default_word_delay = 13 + args.state.word_delay - 8
    if next_storyline.gsub("-", "").gsub("~", "").length <= 4
      default_word_delay = 11 + args.state.word_delay - 8
    end
    number_of_syllabals = next_storyline.length - next_storyline.gsub("-", "").length
    args.state.next_storyline += default_word_delay + number_of_syllabals * (args.state.word_delay + 1)
  end
end

def inputs_reload_current_scene args
  return
  if args.inputs.keyboard.key_down.r!
    reload_current_scene
  end
end

def inputs_dismiss_current_storyline args
  if args.inputs.keyboard.key_down.x!
    args.state.scene_storyline_queue.clear
  end
end

def inputs_restart_game args
  if args.inputs.keyboard.exclamation_point
    args.gtk.reset_state
  end
end

def inputs_change_word_delay args
  if args.inputs.keyboard.key_down.plus || args.inputs.keyboard.key_down.equal_sign
    args.state.word_delay -= 2
    if args.state.word_delay < 0
      args.state.word_delay = 0
      # queue_storyline_text args, "Text speed at MAXIMUM. Geez, how fast do you read?"
    else
      # queue_storyline_text args, "Text speed INCREASED."
    end
  end

  if args.inputs.keyboard.key_down.hyphen || args.inputs.keyboard.key_down.underscore
    args.state.word_delay += 2
    # queue_storyline_text args, "Text speed DECREASED."
  end
end

def multiple_lines args, x, y, texts, size = 0, minimum_alpha = nil
  texts.each_with_index.map do |t, i|
    [x, y - i * (25 + size * 2), t, size, 0, 255, 255, 255, adornments_alpha(args, 255, minimum_alpha)]
  end
end

def lowrez_tick args, lowrez_sprites, lowrez_labels, lowrez_borders, lowrez_solids, lowrez_mouse
  # args.state.show_gridlines = true
  defaults args
  render_current_scene args, lowrez_sprites, lowrez_labels, lowrez_solids
  render_controller args, lowrez_borders
  lowrez_solids << [0, 0, 64, 64, 0, 0, 0]
  calc_storyline_presentation args
  calc_scenes args
  calc_storyline_hotspot args
  inputs_move_player args
  inputs_print_mouse_rect args, lowrez_mouse
  inputs_reload_current_scene args
  inputs_dismiss_current_storyline args
  inputs_change_word_delay args
  inputs_restart_game args
end

def render_controller args, lowrez_borders
  args.state.up_button    = [85, 40, 15, 15, 255, 255, 255]
  args.state.down_button  = [85, 20, 15, 15, 255, 255, 255]
  args.state.left_button  = [65, 20, 15, 15, 255, 255, 255]
  args.state.right_button = [105, 20, 15, 15, 255, 255, 255]
  lowrez_borders << args.state.up_button
  lowrez_borders << args.state.down_button
  lowrez_borders << args.state.left_button
  lowrez_borders << args.state.right_button
end

def inputs_print_mouse_rect args, lowrez_mouse
  if lowrez_mouse.up
    args.state.mouse_held = false
  elsif lowrez_mouse.click
    mouse_rect = [lowrez_mouse.x, lowrez_mouse.y, 1, 1]
    if args.state.up_button.intersect_rect? mouse_rect
      args.state.player.y += 1
    end

    if args.state.down_button.intersect_rect? mouse_rect
      args.state.player.y -= 1
    end

    if args.state.left_button.intersect_rect? mouse_rect
      args.state.player.x -= 1
    end

    if args.state.right_button.intersect_rect? mouse_rect
      args.state.player.x += 1
    end
    args.state.mouse_held = true
  elsif args.state.mouse_held
    mouse_rect = [lowrez_mouse.x, lowrez_mouse.y, 1, 1]
    if args.state.up_button.intersect_rect? mouse_rect
      args.state.player.y += 0.25
    end

    if args.state.down_button.intersect_rect? mouse_rect
      args.state.player.y -= 0.25
    end

    if args.state.left_button.intersect_rect? mouse_rect
      args.state.player.x -= 0.25
    end

    if args.state.right_button.intersect_rect? mouse_rect
      args.state.player.x += 0.25
    end
  end

  if lowrez_mouse.click
    dx = lowrez_mouse.click.x - args.state.previous_mouse_click.x
    dy = lowrez_mouse.click.y - args.state.previous_mouse_click.y
    x, y, w, h = args.state.previous_mouse_click.x, args.state.previous_mouse_click.y, dx, dy
    puts "x #{lowrez_mouse.click.x}, y: #{lowrez_mouse.click.y}"
    if args.state.previous_mouse_click

      if dx < 0 && dx < 0
        x = x + w
        w = w.abs
        y = y + h
        h = h.abs
      end

      w += 1
      h += 1

      args.state.previous_mouse_click = nil
    else
      args.state.previous_mouse_click = lowrez_mouse.click
      square_x, square_y = lowrez_mouse.click
    end
  end
end

def try_centering! word
  word ||= ""
  just_word = word.gsub("-", "").gsub(",", "").gsub(".", "").gsub("'", "").gsub('""', "\"-\"")
  return word if just_word.strip.length == 0
  return word if just_word.include? "~"
  return "~#{word}" if just_word.length <= 2
  if just_word.length.mod_zero? 2
    center_index = just_word.length.idiv(2) - 1
  else
    center_index = (just_word.length - 1).idiv(2)
  end
  return "#{word[0..center_index - 1]}~#{word[center_index]}#{word[center_index + 1..-1]}"
end

def queue_storyline args, scene
  queue_storyline_text args, scene[:storyline]
end

def queue_storyline_text args, text
  args.state.last_story_line_text = text
  args.state.storyline_history << text if text
  words = (text || "").split(" ")
  words = words.map { |w| try_centering! w }
  args.state.scene_storyline_queue = words
  if args.state.scene_storyline_queue.length != 0
    args.state.scene_storyline_queue.unshift "~$--"
    args.state.storyline_to_show = "~."
  else
    args.state.storyline_to_show = ""
  end
  args.state.scene_storyline_queue << ""
  args.state.next_storyline = Kernel.tick_count
end

def set_scene args, scene
  args.state.current_scene = scene
  args.state.background = scene[:background] ||  'sprites/todo.png'
  args.state.scene_fade = scene[:fade] || 0
  args.state.scenes = (scene[:scenes] || []).reject { |s| !s }
  args.state.scene_render_override = scene[:render_override]
  args.state.storylines = (scene[:storylines] || []).reject { |s| !s }
  args.state.scene_changed_at = Kernel.tick_count
  if scene[:player]
    args.state.player = scene[:player]
  end
  args.state.inside_scene_hotspot = false
  args.state.inside_storyline_hotspot = false
  queue_storyline args, scene
end

def replay_storyline_rect
  [26, -1, 7, 4]
end

def labels_for_word word
  left_side_of_word = ""
  center_letter = ""
  right_side_of_word = ""

  if word[0] == "~"
    left_side_of_word = ""
    center_letter = word[1]
    right_side_of_word = word[2..-1]
  elsif word.length > 0
    left_side_of_word, right_side_of_word = word.split("~")
    center_letter = right_side_of_word[0]
    right_side_of_word = right_side_of_word[1..-1]
  end

  right_side_of_word = right_side_of_word.gsub("-", "")

  {
    left:   [29 - left_side_of_word.length * 4 - 1 * left_side_of_word.length, 2, left_side_of_word],
    center: [29, 2, center_letter, 255, 0, 0],
    right:  [34, 2, right_side_of_word]
  }
end

def render_scenes args, lowrez_sprites
  lowrez_sprites << args.state.scenes.flat_map do |hs|
    hotspot_square args, hs.x, hs.y, hs.w, hs.h
  end
end

def render_storylines args, lowrez_sprites
  lowrez_sprites << args.state.storylines.flat_map do |hs|
    hotspot_square args, hs.x, hs.y, hs.w, hs.h
  end
end

def adornments_alpha args, target_alpha = nil, minimum_alpha = nil
  return (minimum_alpha || 80) unless args.state.storyline_queue_empty_at
  target_alpha ||= 255
  target_alpha * args.state.storyline_queue_empty_at.ease(60)
end

def hotspot_square args, x, y, w, h
  if w >= 3 && h >= 3
    [
      [x + w.idiv(2) + 1, y, w.idiv(2), h, 'sprites/label-background.png', 0, adornments_alpha(args, 50), 23, 23, 23],
      [x, y, w.idiv(2), h, 'sprites/label-background.png', 0, adornments_alpha(args, 100), 223, 223, 223],
      [x + 1, y + 1, w - 2, h - 2, 'sprites/label-background.png', 0, adornments_alpha(args, 200), 40, 140, 40],
    ]
  else
    [
      [x, y, w, h, 'sprites/label-background.png', 0, adornments_alpha(args, 200), 0, 140, 0],
    ]
  end
end

def render_storyline_dialog args, lowrez_labels, lowrez_sprites
  return unless args.state.is_storyline_dialog_active
  return unless args.state.storyline_to_show
  labels = labels_for_word args.state.storyline_to_show
  if true # high rez version
    scale = 8.88
    offset = 45
    size = 25
    args.outputs.labels << [offset + labels[:left].x.-(1) * scale,
                            labels[:left].y * TINY_SCALE + 55,
                            labels[:left].text, size, 0, 0, 0, 0, 255,
                            'fonts/manaspc.ttf']
    center_text = labels[:center].text
    center_text = "|" if center_text == "$"
    args.outputs.labels << [offset + labels[:center].x * scale,
                            labels[:center].y * TINY_SCALE + 55,
                            center_text, size, 0, 255, 0, 0, 255,
                            'fonts/manaspc.ttf']
    args.outputs.labels << [offset + labels[:right].x * scale,
                            labels[:right].y * TINY_SCALE + 55,
                            labels[:right].text, size, 0, 0, 0, 0, 255,
                            'fonts/manaspc.ttf']
  else
    lowrez_labels << labels[:left]
    lowrez_labels << labels[:center]
    lowrez_labels << labels[:right]
  end
  args.state.is_storyline_dialog_active = true
  render_player args, lowrez_sprites
  lowrez_sprites <<  [0, 0, 64, 8, 'sprites/label-background.png']
end

def render_player args, lowrez_sprites
  lowrez_sprites << player_md_down(args, *args.state.player)
end

def render_adornments args, lowrez_sprites
  render_scenes args, lowrez_sprites
  render_storylines args, lowrez_sprites
  return if args.state.is_storyline_dialog_active
  lowrez_sprites << player_md_down(args, *args.state.player)
end

def global_alpha_percentage args, max_alpha = 255
  return 255 unless args.state.scene_changed_at
  return 255 unless args.state.scene_fade
  return 255 unless args.state.scene_fade > 0
  return max_alpha * args.state.scene_changed_at.ease(args.state.scene_fade)
end

def render_current_scene args, lowrez_sprites, lowrez_labels, lowrez_solids
  lowrez_sprites << [0, 0, 64, 64, args.state.background, 0, (global_alpha_percentage args)]
  if args.state.scene_render_override
    send args.state.scene_render_override, args, lowrez_sprites, lowrez_labels, lowrez_solids
  end
  storyline_to_show = args.state.storyline_to_show || ""
  render_adornments args, lowrez_sprites
  render_storyline_dialog args, lowrez_labels, lowrez_sprites

  if args.state.background == 'sprites/tribute-game-over.png'
    lowrez_sprites << [0, 0, 64, 11, 'sprites/label-background.png', 0, adornments_alpha(args, 200), 0, 0, 0]
    lowrez_labels << [9, 6, 'Return of', 255, 255, 255]
    lowrez_labels << [9, 1, ' Serenity', 255, 255, 255]
    if !args.state.ended
      args.gtk.stop_music
      args.outputs.sounds << 'sounds/music-loop.ogg'
      args.state.ended = true
    end
  end
end

def player_md_right args, x, y
  [x, y, 4, 11, 'sprites/player-right.png', 0, (global_alpha_percentage args)]
end

def player_md_left args, x, y
  [x, y, 4, 11, 'sprites/player-left.png', 0, (global_alpha_percentage args)]
end

def player_md_up args, x, y
  [x, y, 4, 11, 'sprites/player-up.png', 0, (global_alpha_percentage args)]
end

def player_md_down args, x, y
  [x, y, 4, 11, 'sprites/player-down.png', 0, (global_alpha_percentage args)]
end

def player_sm args, x, y
  [x, y, 3, 7, 'sprites/player-zoomed-out.png', 0, (global_alpha_percentage args)]
end

def player_xs args, x, y
  [x, y, 1, 4, 'sprites/player-zoomed-out.png', 0, (global_alpha_percentage args)]
end

Return Of Serenity - require.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/require.rb
require 'app/lowrez_simulator.rb'
require 'app/storyline_day_one.rb'
require 'app/storyline_blinking_light.rb'
require 'app/storyline_serenity_introduction.rb'
require 'app/storyline_speed_of_light.rb'
require 'app/storyline_serenity_alive.rb'
require 'app/storyline_serenity_bio.rb'
require 'app/storyline_anka.rb'
require 'app/storyline_final_message.rb'
require 'app/storyline_final_decision.rb'
require 'app/storyline.rb'

Return Of Serenity - storyline.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline.rb
def hotspot_top
  [4, 61, 56, 3]
end

def hotspot_bottom
  [4, 0, 56, 3]
end

def hotspot_top_right
  [62, 35, 3, 25]
end

def hotspot_bottom_right
  [62, 0, 3, 25]
end

def storyline_history_include? args, text
  args.state.storyline_history.any? { |s| s.gsub("-", "").gsub(" ", "").include? text.gsub("-", "").gsub(" ", "") }
end

def blinking_light_side_of_home_render args, lowrez_sprites, lowrez_labels, lowrez_solids
  lowrez_sprites << [48, 44, 5, 5, 'sprites/square.png', 0,  50 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [49, 45, 3, 3, 'sprites/square.png', 0, 100 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [50, 46, 1, 1, 'sprites/square.png', 0, 255 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
end

def blinking_light_mountain_pass_render args, lowrez_sprites, lowrez_labels, lowrez_solids
  lowrez_sprites << [18, 47, 5, 5, 'sprites/square.png', 0,  50 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [19, 48, 3, 3, 'sprites/square.png', 0, 100 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [20, 49, 1, 1, 'sprites/square.png', 0, 255 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
end

def blinking_light_path_to_observatory_render args, lowrez_sprites, lowrez_labels, lowrez_solids
  lowrez_sprites << [0, 26, 5, 5, 'sprites/square.png', 0,  50 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [1, 27, 3, 3, 'sprites/square.png', 0, 100 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [2, 28, 1, 1, 'sprites/square.png', 0, 255 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
end

def blinking_light_observatory_render args, lowrez_sprites, lowrez_labels, lowrez_solids
  lowrez_sprites << [23, 59, 5, 5, 'sprites/square.png', 0,  50 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [24, 60, 3, 3, 'sprites/square.png', 0, 100 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [25, 61, 1, 1, 'sprites/square.png', 0, 255 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
end

def blinking_light_inside_observatory_render args, lowrez_sprites, lowrez_labels, lowrez_solids
  lowrez_sprites << [30, 30, 5, 5, 'sprites/square.png', 0,  50 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [31, 31, 3, 3, 'sprites/square.png', 0, 100 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
  lowrez_sprites << [32, 32, 1, 1, 'sprites/square.png', 0, 255 * (Kernel.tick_count % 50).fdiv(50), 0, 255, 0]
end

def decision_graph context_message, context_action, context_result_one, context_result_two, context_result_three = [], context_result_four = []
  result_one_scene, result_one_label, result_one_text = context_result_one
  result_two_scene, result_two_label, result_two_text = context_result_two
  result_three_scene, result_three_label, result_three_text = context_result_three
  result_four_scene, result_four_label, result_four_text = context_result_four

  top_level_hash = {
    background: 'sprites/decision.png',
    fade: 60,
    player: [20, 36],
    storylines: [ ],
    scenes: [ ]
  }

  confirmation_result_one_hash = {
    background: 'sprites/decision.png',
    scenes: [ ],
    storylines: [ ]
  }

  confirmation_result_two_hash = {
    background: 'sprites/decision.png',
    scenes: [ ],
    storylines: [ ]
  }

  confirmation_result_three_hash = {
    background: 'sprites/decision.png',
    scenes: [ ],
    storylines: [ ]
  }

  confirmation_result_four_hash = {
    background: 'sprites/decision.png',
    scenes: [ ],
    storylines: [ ]
  }

  top_level_hash[:storylines] << [ 5, 35, 4, 4, context_message]
  top_level_hash[:storylines] << [20, 35, 4, 4, context_action]

  confirmation_result_one_hash[:scenes]       << [20, 35, 4, 4, top_level_hash]
  confirmation_result_one_hash[:scenes]       << [60, 50, 4, 4, result_one_scene]
  confirmation_result_one_hash[:storylines]   << [40, 50, 4, 4, "#{result_one_label}: \"#{result_one_text}\""]
  confirmation_result_one_hash[:scenes]       << [40, 40, 4, 4, confirmation_result_four_hash] if result_four_scene
  confirmation_result_one_hash[:scenes]       << [40, 30, 4, 4, confirmation_result_three_hash] if result_three_scene
  confirmation_result_one_hash[:scenes]       << [40, 20, 4, 4, confirmation_result_two_hash]

  confirmation_result_two_hash[:scenes]       << [20, 35, 4, 4, top_level_hash]
  confirmation_result_two_hash[:scenes]       << [40, 50, 4, 4, confirmation_result_one_hash]
  confirmation_result_two_hash[:scenes]       << [40, 40, 4, 4, confirmation_result_four_hash] if result_four_scene
  confirmation_result_two_hash[:scenes]       << [40, 30, 4, 4, confirmation_result_three_hash] if result_three_scene
  confirmation_result_two_hash[:scenes]       << [60, 20, 4, 4, result_two_scene]
  confirmation_result_two_hash[:storylines]   << [40, 20, 4, 4, "#{result_two_label}: \"#{result_two_text}\""]

  confirmation_result_three_hash[:scenes]     << [20, 35, 4, 4, top_level_hash]
  confirmation_result_three_hash[:scenes]     << [40, 50, 4, 4, confirmation_result_one_hash]
  confirmation_result_three_hash[:scenes]     << [40, 40, 4, 4, confirmation_result_four_hash]
  confirmation_result_three_hash[:scenes]     << [60, 30, 4, 4, result_three_scene]
  confirmation_result_three_hash[:storylines] << [40, 30, 4, 4, "#{result_three_label}: \"#{result_three_text}\""]
  confirmation_result_three_hash[:scenes]     << [40, 20, 4, 4, confirmation_result_two_hash]

  confirmation_result_four_hash[:scenes]      << [20, 35, 4, 4, top_level_hash]
  confirmation_result_four_hash[:scenes]      << [40, 50, 4, 4, confirmation_result_one_hash]
  confirmation_result_four_hash[:scenes]      << [60, 40, 4, 4, result_four_scene]
  confirmation_result_four_hash[:storylines]  << [40, 40, 4, 4, "#{result_four_label}: \"#{result_four_text}\""]
  confirmation_result_four_hash[:scenes]      << [40, 30, 4, 4, confirmation_result_three_hash]
  confirmation_result_four_hash[:scenes]      << [40, 20, 4, 4, confirmation_result_two_hash]

  top_level_hash[:scenes]     << [40, 50, 4, 4, confirmation_result_one_hash]
  top_level_hash[:scenes]     << [40, 40, 4, 4, confirmation_result_four_hash] if result_four_scene
  top_level_hash[:scenes]     << [40, 30, 4, 4, confirmation_result_three_hash] if result_three_scene
  top_level_hash[:scenes]     << [40, 20, 4, 4, confirmation_result_two_hash]

  top_level_hash
end

def ship_control_hotspot offset_x, offset_y, a, b, c, d
  results = []
  results << [ 6 + offset_x, 0 + offset_y, 4, 4, a]  if a
  results << [ 1 + offset_x, 5 + offset_y, 4, 4, b]  if b
  results << [ 6 + offset_x, 5 + offset_y, 4, 4, c]  if c
  results << [ 11 + offset_x, 5 + offset_y, 4, 4, d] if d
  results
end

def reload_current_scene
  if $gtk.args.state.last_hotspot_scene
    set_scene $gtk.args, send($gtk.args.state.last_hotspot_scene, $gtk.args)
    tick $gtk.args
  elsif respond_to? :set_scene
    set_scene $gtk.args, (replied_to_serenity_alive_firmly $gtk.args)
    tick $gtk.args
  end
  $gtk.console.close
end

Return Of Serenity - storyline_anka.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline_anka.rb
def anka_inside_room args
  {
    background: 'sprites/inside-home.png',
    player: [34, 35],
    storylines: [
      [34, 34, 4, 4, "Ahhhh!!! Oh god, it was just- a nightmare."],
    ],
    scenes: [
      [32, -1, 8, 3, :anka_observatory]
    ]
  }
end

def anka_observatory args
  {
    background: 'sprites/inside-observatory.png',
    fade: 60,
    player: [51, 12],
    storylines: [
      [50, 10, 4, 4,   "Breathe, Hiro. Just see what's there... everything--- will- be okay."]
    ],
    scenes: [
      [30, 18, 5, 12, :anka_inside_mainframe]
    ],
    render_override: :blinking_light_inside_observatory_render
  }
end

def anka_inside_mainframe args
  {
    player: [32, 4],
    background: 'sprites/mainframe.png',
    fade: 60,
    storylines: [
      [22, 45, 17, 4, (anka_last_reply args)],
      [45, 45,  4, 4, (anka_current_reply args)],
    ],
    scenes: [
      [*hotspot_top_right, :reply_to_anka]
    ]
  }
end

def reply_to_anka args
  decision_graph anka_current_reply(args),
                 "Matthew's-- wife is doing-- well. What's-- even-- better-- is that he's-- a dad, and he didn't-- even-- know it. Should- I- leave- out the part about-- the crew- being-- in hibernation-- for 20-- years? They- should- enter-- statis-- on a high- note... Right?",
                 [:replied_with_whole_truth, "Whole-- Truth--", anka_reply_whole_truth],
                 [:replied_with_half_truth, "Half-- Truth--", anka_reply_half_truth]
end

def anka_last_reply args
  if args.state.scene_history.include? :replied_to_serenity_alive_firmly
    return "Buffer--: #{serenity_alive_firm_reply.quote}"
  else
    return "Buffer--: #{serenity_alive_sugarcoated_reply.quote}"
  end
end

def anka_reply_whole_truth
  "Matthew's wife is doing-- very-- well. In fact, she was pregnant. Matthew-- is a dad. He has a son. But, I need- all-- of-- you-- to brace-- yourselves. You've-- been in statis-- for 20 years. A lot has changed. Most of Earth's-- population--- didn't-- survive. Tell- Matthew-- that I'm-- sorry he didn't-- get to see- his- son grow- up."
end

def anka_reply_half_truth
  "Matthew's--- wife- is doing-- very-- well. In fact, she was pregnant. Matthew is a dad! It's a boy! Tell- Matthew-- congrats-- for me. Hope-- to see- all of you- soon."
end

def replied_with_whole_truth args
  {
    background: 'sprites/inside-observatory.png',
    fade: 60,
    player: [32, 21],
    scenes: [[60, 0, 4, 32, :replied_to_anka_back_home]],
    storylines: [
      [30, 18, 5, 12, "Buffer-- has been set to: #{anka_reply_whole_truth.quote}"],
      [30, 10, 5, 4, "I- hope- I- did the right- thing- by laying-- it all- out- there."],
    ]
  }
end

def replied_with_half_truth args
  {
    background: 'sprites/inside-observatory.png',
    fade: 60,
    player: [32, 21],
    scenes: [[60, 0, 4, 32, :replied_to_anka_back_home]],
    storylines: [
      [30, 18, 5, 12, "Buffer-- has been set to: #{anka_reply_half_truth.quote}"],
      [30, 10, 5, 4, "I- hope- I- did the right- thing- by not giving-- them- the whole- truth."],
    ]
  }
end

def anka_current_reply args
  if args.state.scene_history.include? :replied_to_serenity_alive_firmly
    return "Hello. This is, Aanka. Sasha-- is still- trying-- to gather-- her wits about-- her, given- the gravity--- of your- last- reply. Thank- you- for being-- honest, and thank- you- for the help- with the ship- diagnostics. I was able-- to retrieve-- all of the navigation--- information---- after-- the battery--- swap. We- are ready-- to head back to Earth. Before-- we go- back- into-- statis, Matthew--- wanted-- to know- how his- wife- is doing. Please- reply-- as soon- as you can. He's-- not going-- to get- into-- the statis-- chamber-- until-- he knows- his wife is okay."
  else
    return "Hello. This is, Aanka. Thank- you for the help- with the ship's-- diagnostics. I was able-- to retrieve-- all of the navigation--- information--- after-- the battery-- swap. I- know-- that- you didn't-- tell- the whole truth- about-- how far we are from- Earth. Don't-- worry. I understand-- why you did it. We- are ready-- to head back to Earth. Before-- we go- back- into-- statis, Matthew--- wanted-- to know- how his- wife- is doing. Please- reply-- as soon- as you can. He's-- not going-- to get- into-- the statis-- chamber-- until-- he knows- his wife is okay."
  end
end

def replied_to_anka_back_home args
  if args.state.scene_history.include? :replied_with_whole_truth
    return {
      fade: 60,
      background: 'sprites/inside-home.png',
      player: [34, 4],
      storylines: [
        [34, 4, 4, 4, "I- hope-- this pit in my stomach-- is gone-- by tomorrow---."],
      ],
      scenes: [
        [30, 38, 12, 13, :final_message_sad],
      ]
    }
  else
    return {
      fade: 60,
      background: 'sprites/inside-home.png',
      player: [34, 4],
      storylines: [
        [34, 4, 4, 4, "I- get the feeling-- I'm going-- to sleep real well tonight--."],
      ],
      scenes: [
        [30, 38, 12, 13, :final_message_happy],
      ]
    }
  end
end

Return Of Serenity - storyline_blinking_light.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline_blinking_light.rb
def the_blinking_light args
  {
    fade: 60,
    background: 'sprites/side-of-home.png',
    player: [16, 13],
    scenes: [
      [52, 24, 11, 5, :blinking_light_mountain_pass],
    ],
    render_override: :blinking_light_side_of_home_render
  }
end

def blinking_light_mountain_pass args
  {
    background: 'sprites/mountain-pass-zoomed-out.png',
    player: [4, 4],
    scenes: [
      [18, 47, 5, 5, :blinking_light_path_to_observatory]
    ],
    render_override: :blinking_light_mountain_pass_render
  }
end

def blinking_light_path_to_observatory args
  {
    background: 'sprites/path-to-observatory.png',
    player: [60, 4],
    scenes: [
      [0, 26, 5, 5, :blinking_light_observatory]
    ],
    render_override: :blinking_light_path_to_observatory_render
  }
end

def blinking_light_observatory args
  {
    background: 'sprites/observatory.png',
    player: [60, 2],
    scenes: [
      [28, 39, 4, 10, :blinking_light_inside_observatory]
    ],
    render_override: :blinking_light_observatory_render
  }
end

def blinking_light_inside_observatory args
  {
    background: 'sprites/inside-observatory.png',
    player: [60, 2],
    storylines: [
      [50, 2, 4, 8,   "That's weird. I thought- this- mainframe-- was broken--."]
    ],
    scenes: [
      [30, 18, 5, 12, :blinking_light_inside_mainframe]
    ],
    render_override: :blinking_light_inside_observatory_render
  }
end

def blinking_light_inside_mainframe args
  {
    background: 'sprites/mainframe.png',
    fade: 60,
    player: [30, 4],
    scenes: [
      [62, 32, 4, 32, :reply_to_introduction]
    ],
    storylines: [
      [43, 43,  8, 8, "\"Mission-- control--, your- main- comm-- channels-- seem-- to be down. My apologies-- for- using-- this low- level-- exploit--. What's-- going-- on down there? We are ready-- for reentry--.\" Message--- Timestamp---: 4- hours-- 23--- minutes-- ago--."],
      [30, 30,  4, 4, "There's-- a low- level-- message-- here... NANI.T.F?"],
      [14, 10, 24, 4, "Oh interesting---. This transistor--- needed-- to be activated--- for the- mainframe-- to work."],
      [14, 20, 24, 4, "What the heck activated--- this thing- though?"]
    ]
  }
end

Return Of Serenity - storyline_day_one.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline_day_one.rb
def day_one_beginning args
  {
    background: 'sprites/side-of-home.png',
    player: [16, 13],
    scenes: [
      [0, 0, 64, 2, :day_one_infront_of_home],
    ],
    storylines: [
      [35, 10, 6, 6,  "Man. Hard to believe- that today- is the 20th--- anniversary-- of The Impact."]
    ]
  }
end

def day_one_infront_of_home args
  {
    background: 'sprites/front-of-home.png',
    player: [56, 23],
    scenes: [
      [43, 34, 10, 16, :day_one_home],
      [62, 0,  3, 40, :day_one_beginning],
      [0, 4, 3, 20, :day_one_ceremony]
    ],
    storylines: [
      [40, 20, 4, 4, "It looks like everyone- is already- at the rememberance-- ceremony."],
    ]
  }
end

def day_one_home args
  {
    background: 'sprites/inside-home.png',
    player: [34, 3],
    scenes: [
      [28, 0, 12, 2, :day_one_infront_of_home]
    ],
    storylines: [
      [
        38, 4, 4, 4, "My mansion- in all its glory! Okay yea, it's just a shipping- container-. Apparently-, it's nothing- like the luxuries- of the 2040's. But it's- all we have- in- this day and age. And it'll suffice."
      ],
      [
        28, 7, 4, 7,
        "Ahhh. My reading- couch. It's so comfortable--."
      ],
      [
        38, 21, 4, 4,
        "I'm- lucky- to have a computer--. I'm- one of the few people- with- the skills to put this- thing to good use."
      ],
      [
        45, 37, 4, 8,
        "This corner- of my home- is always- warmer-. It's cause of the ref~lected-- light- from the solar-- panels--, just on the other- side- of this wall. It's hard- to believe- there was o~nce-- an unlimited- amount- of electricity--."
      ],
      [
        32, 40, 8, 10,
        "This isn't- a good time- to sleep. I- should probably- head to the ceremony-."
      ],
      [
        25, 21, 5, 12,
        "Fifteen-- years- of computer-- science-- notes, neatly-- organized. Compiler--- Theory--, Linear--- Algebra---, Game-- Development---... Every-- subject-- imaginable--."
      ]
    ]
  }
end

def day_one_ceremony args
  {
    background: 'sprites/tribute.png',
    player: [57, 21],
    scenes: [
      [62, 0, 2, 40, :day_one_infront_of_home],
      [0, 24, 2, 40, :day_one_infront_of_library]
    ],
    storylines: [
      [53, 12, 3,  8,  "It's- been twenty- years since The Impact. Twenty- years, since Halley's-- Comet-- set Earth's- blue- sky on fire."],
      [45, 12, 3,  8,  "The space mission- sent to prevent- Earth's- total- destruction--, was a success. Only- 99.9%------ of the world's- population-- died-- that day. Hey, it's- better-- than 100%---- of humanity-- dying."],
      [20, 12, 23, 4, "The monument--- reads:---- Here- stands- the tribute-- to Space- Mission-- Serenity--- and- its- crew. You- have- given-- humanity--- a second-- chance."],
      [15, 12, 3,  8, "Rest- in- peace--- Matthew----, Sasha----, Aanka----"],
    ]
  }
end

def day_one_infront_of_library args
  {
    background: 'sprites/outside-library.png',
    player: [57, 21],
    scenes: [
      [62, 0, 2, 40, :day_one_ceremony],
      [49, 39, 6, 9, :day_one_library]
    ],
    storylines: [
      [50, 20, 4, 8,  "Shipping- containers-- as far- as the eye- can see. It's- rather- beautiful-- if you ask me. Even- though-- this- view- represents-- all- that's-- left- of humanity-."]
    ]
  }
end

def day_one_library args
  {
    background: 'sprites/library.png',
    player: [27, 4],
    scenes: [
      [0, 0, 64, 2, :end_day_one_infront_of_library]
    ],
    storylines: [
      [28, 22, 8, 4,  "I grew- up- in this library. I've- read every- book- here. My favorites-- were- of course-- anything- computer-- related."],
      [6, 32, 10, 6, "My favorite-- area--- of the library. The Science-- Section."]
    ]
  }
end

def end_day_one_infront_of_library args
  {
    background: 'sprites/outside-library.png',
    player: [51, 33],
    scenes: [
      [49, 39, 6, 9, :day_one_library],
      [62, 0, 2, 40, :end_day_one_monument],
    ],
    storylines: [
      [50, 27, 4, 4, "It's getting late. Better get some sleep."]
    ]
  }
end

def end_day_one_monument args
  {
    background: 'sprites/tribute.png',
    player: [2, 36],
    scenes: [
      [62, 0, 2, 40, :end_day_one_infront_of_home],
    ],
    storylines: [
      [50, 27, 4, 4, "It's getting late. Better get some sleep."],
    ]
  }
end

def end_day_one_infront_of_home args
  {
    background: 'sprites/front-of-home.png',
    player: [1, 17],
    scenes: [
      [43, 34, 10, 16, :end_day_one_home],
    ],
    storylines: [
      [20, 10, 4, 4, "It's getting late. Better get some sleep."],
    ]
  }
end

def end_day_one_home args
  {
    background: 'sprites/inside-home.png',
    player: [34, 3],
    scenes: [
      [32, 40, 8, 10, :end_day_one_dream],
    ],
    storylines: [
      [38, 4, 4, 4, "It's getting late. Better get some sleep."],
    ]
  }
end

def end_day_one_dream args
  {
    background: 'sprites/dream.png',
    fade: 60,
    player: [4, 4],
    scenes: [
      [62, 0, 2, 64, :explaining_the_special_power]
    ],
    storylines: [
      [10, 10, 4, 4, "Why- does this- moment-- always- haunt- my dreams?"],
      [20, 10, 4, 4, "This kid- reads these computer--- science--- books- nonstop-. What's- wrong with him?"],
      [30, 10, 4, 4, "There- is nothing-- wrong- with him. This behavior-- should be encouraged---! In fact-, I think- he's- special---. Have- you seen- him use- a computer---? It's-- almost-- as if he can- speak-- to it."]
    ]
  }
end

def explaining_the_special_power args
  {
    fade: 60,
    background: 'sprites/inside-home.png',
    player: [32, 30],
    scenes: [
      [
        38, 21, 4, 4, :explaining_the_special_power_inside_computer
      ],
    ]
  }
end

def explaining_the_special_power_inside_computer args
  {
    background: 'sprites/pc.png',
    fade: 60,
    player: [34, 4],
    scenes: [
      [0, 62, 64, 3, :the_blinking_light]
    ],
    storylines: [
      [14, 20, 24, 4, "So... I have a special-- power--. I don't-- need a mouse-, keyboard--, or even-- a monitor--- to control-- a computer--."],
      [14, 25, 24, 4, "I only-- pretend-- to use peripherals---, so as not- to freak- anyone--- out."],
      [14, 30, 24, 4, "Inside-- this silicon--- Universe---, is the only-- place I- feel- at peace."],
      [14, 35, 24, 4, "It's-- the only-- place where I don't-- feel alone."]
    ]
  }
end

Return Of Serenity - storyline_final_decision.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline_final_decision.rb
def final_decision_side_of_home args
  {
    fade: 120,
    background: 'sprites/side-of-home.png',
    player: [16, 13],
    scenes: [
      [52, 24, 11, 5, :final_decision_mountain_pass],
    ],
    render_override: :blinking_light_side_of_home_render,
    storylines: [
      [28, 13, 8, 4,  "Man. Hard to believe- that today- is the 21st--- anniversary-- of The Impact. Serenity--- will- be- home- soon."]
    ]
  }
end

def final_decision_mountain_pass args
  {
    background: 'sprites/mountain-pass-zoomed-out.png',
    player: [4, 4],
    scenes: [
      [18, 47, 5, 5, :final_decision_path_to_observatory]
    ],
    render_override: :blinking_light_mountain_pass_render
  }
end

def final_decision_path_to_observatory args
  {
    background: 'sprites/path-to-observatory.png',
    player: [60, 4],
    scenes: [
      [0, 26, 5, 5, :final_decision_observatory]
    ],
    render_override: :blinking_light_path_to_observatory_render
  }
end

def final_decision_observatory args
  {
    background: 'sprites/observatory.png',
    player: [60, 2],
    scenes: [
      [28, 39, 4, 10, :final_decision_inside_observatory]
    ],
    render_override: :blinking_light_observatory_render
  }
end

def final_decision_inside_observatory args
  {
    background: 'sprites/inside-observatory.png',
    player: [60, 2],
    storylines: [],
    scenes: [
      [30, 18, 5, 12, :final_decision_inside_mainframe]
    ],
    render_override: :blinking_light_inside_observatory_render
  }
end

def final_decision_inside_mainframe args
  {
    player: [32, 4],
    background: 'sprites/mainframe.png',
    storylines: [],
    scenes: [
      [*hotspot_top, :final_decision_ship_status],
    ]
  }
end

def final_decision_ship_status args
  {
    background: 'sprites/serenity.png',
    fade: 60,
    player: [30, 10],
    scenes: [
      [*hotspot_top_right, :final_decision]
    ],
    storylines: [
      [30,  8, 4, 4, "????"],
      *final_decision_ship_status_shared(args)
    ]
  }
end

def final_decision args
  decision_graph  "Stasis-- Chambers--: UNDERPOWERED, Life- forms-- will be terminated---- unless-- equilibrium----- is reached.",
                  "I CAN'T DO THIS... But... If-- I-- don't--- bring-- the- chambers--- to- equilibrium-----, they all die...",
                  [:final_decision_game_over_noone, "Kill--- Everyone---", "DO--- NOTHING?"],
                  [:final_decision_game_over_matthew, "Kill--- Sasha---", "KILL--- SASHA?"],
                  [:final_decision_game_over_anka, "Kill--- Aanka---", "KILL--- AANKA?"],
                  [:final_decision_game_over_sasha, "Kill--- Matthew---", "KILL--- MATTHEW?"]
end

def final_decision_game_over_noone args
  {
    background: 'sprites/tribute-game-over.png',
    player: [53, 14],
    fade: 600
  }
end

def final_decision_game_over_matthew args
  {
    background: 'sprites/tribute-game-over.png',
    player: [53, 14],
    fade: 600
  }
end

def final_decision_game_over_anka args
  {
    background: 'sprites/tribute-game-over.png',
    player: [53, 14],
    fade: 600
  }
end

def final_decision_game_over_sasha args
  {
    background: 'sprites/tribute-game-over.png',
    player: [53, 14],
    fade: 600
  }
end

def final_decision_ship_status_shared args
  [
    *ship_control_hotspot(24, 22,
                           "Stasis-- Chambers--: UNDERPOWERED, Life- forms-- will be terminated---- unless-- equilibrium----- is reached. WHAT?! NO!",
                           "Matthew's--- Chamber--: UNDER-- THREAT-- OF-- TERMINATION. WHAT?! NO!",
                           "Aanka's--- Chamber--: UNDER-- THREAT-- OF-- TERMINATION.  WHAT?! NO!",
                           "Sasha's--- Chamber--: UNDER-- THREAT-- OF-- TERMINATION. WHAT?! NO!"),
  ]
end

Return Of Serenity - storyline_final_message.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline_final_message.rb
def final_message_sad args
  {
    fade: 60,
    background: 'sprites/inside-home.png',
    player: [34, 35],
    storylines: [
      [34, 34, 4, 4, "Another-- sleepless-- night..."],
    ],
    scenes: [
      [32, -1, 8, 3, :final_message_observatory]
    ]
  }
end

def final_message_happy args
  {
    fade: 60,
    background: 'sprites/inside-home.png',
    player: [34, 35],
    storylines: [
      [34, 34, 4, 4, "Oh man, I slept like rock!"],
    ],
    scenes: [
      [32, -1, 8, 3, :final_message_observatory]
    ]
  }
end

def final_message_side_of_home args
  {
    fade: 60,
    background: 'sprites/side-of-home.png',
    player: [16, 13],
    scenes: [
      [52, 24, 11, 5, :final_message_mountain_pass],
    ],
    render_override: :blinking_light_side_of_home_render
  }
end

def final_message_mountain_pass args
  {
    background: 'sprites/mountain-pass-zoomed-out.png',
    player: [4, 4],
    scenes: [
      [18, 47, 5, 5, :final_message_path_to_observatory],
    ],
    storylines: [
      [18, 13, 5, 5, "Hnnnnnnnggg. My legs-- are still sore- from yesterday."]
    ],
    render_override: :blinking_light_mountain_pass_render
  }
end

def final_message_path_to_observatory args
  {
    background: 'sprites/path-to-observatory.png',
    player: [60, 4],
    scenes: [
      [0, 26, 5, 5, :final_message_observatory]
    ],
    storylines: [
      [22, 20, 10, 10, "This spot--, on the mountain, right here, it's-- perfect. This- is where- I'll-- yeet-- the person-- who is playing-- this- prank- on me."]
    ],
    render_override: :blinking_light_path_to_observatory_render
  }
end

def final_message_observatory args
  if args.state.scene_history.include? :replied_with_whole_truth
    return {
      background: 'sprites/inside-observatory.png',
      fade: 60,
      player: [51, 12],
      storylines: [
        [50, 10, 4, 4, "Here-- we- go..."]
      ],
      scenes: [
        [30, 18, 5, 12, :final_message_inside_mainframe]
      ],
      render_override: :blinking_light_inside_observatory_render
    }
  else
    return {
      background: 'sprites/inside-observatory.png',
      fade: 60,
      player: [51, 12],
      storylines: [
        [50, 10, 4, 4, "I feel like I'm-- walking-- on sunshine!"]
      ],
      scenes: [
        [30, 18, 5, 12, :final_message_inside_mainframe]
      ],
      render_override: :blinking_light_inside_observatory_render
    }
  end
end

def final_message_inside_mainframe args
  {
    player: [32, 4],
    background: 'sprites/mainframe.png',
    fade: 60,
    scenes: [[45, 45,  4, 4, :final_message_check_ship_status]]
  }
end

def final_message_check_ship_status args
  {
    background: 'sprites/mainframe.png',
    storylines: [
      [45, 45, 4, 4, (final_message_current args)],
    ],
    scenes: [
      [*hotspot_top, :final_message_ship_status],
    ]
  }
end

def final_message_ship_status args
  {
    background: 'sprites/serenity.png',
    fade: 60,
    player: [30, 10],
    scenes: [
      [30, 50, 4, 4, :final_message_ship_status_reviewed]
    ],
    storylines: [
      [30,  8, 4, 4, "Let me make- sure- everything--- looks good. It'll-- give me peace- of mind."],
      *final_message_ship_status_shared(args)
    ]
  }
end

def final_message_ship_status_reviewed args
  {
    background: 'sprites/serenity.png',
    fade: 60,
    scenes: [
      [*hotspot_bottom, :final_message_summary]
    ],
    storylines: [
      [0, 62, 62, 3, "Whew. Everyone-- is in their- chambers. The engines-- are roaring-- and Serenity-- is coming-- home."],
    ]
  }
end

def final_message_ship_status_shared args
  [
    *ship_control_hotspot( 0, 50,
                           "Stasis-- Chambers--: Online, All chambers-- are powered. Battery--- Allocation---: 3--- of-- 3--.",
                           "Matthew's--- Chamber--: OCCUPIED----",
                           "Aanka's--- Chamber--: OCCUPIED----",
                           "Sasha's--- Chamber--: OCCUPIED----"),
    *ship_control_hotspot(12, 35,
                          "Life- Support--: Not-- Needed---",
                          "O2--- Production---: OFF---",
                          "CO2--- Scrubbers---: OFF---",
                          "H2O--- Production---: OFF---"),
    *ship_control_hotspot(24, 20,
                          "Navigation: Offline---",
                          "Sensor: OFF---",
                          "Heads- Up- Display: DAMAGED---",
                          "Arithmetic--- Unit: DAMAGED----"),
    *ship_control_hotspot(36, 35,
                          "COMM: Underpowered----",
                          "Text: ON---",
                          "Audio: SEGFAULT---",
                          "Video: DAMAGED---"),
    *ship_control_hotspot(48, 50,
                          "Engine: Online, Coordinates--- Set- for Earth. Battery--- Allocation---: 3--- of-- 3---",
                          "Engine I: ON---",
                          "Engine II: ON---",
                          "Engine III: ON---")
  ]
end

def final_message_last_reply args
  if args.state.scene_history.include? :replied_with_whole_truth
    return "Buffer--: #{anka_reply_whole_truth.quote}"
  else
    return "Buffer--: #{anka_reply_half_truth.quote}"
  end
end

def final_message_current args
  if args.state.scene_history.include? :replied_with_whole_truth
    return "Hey... It's-- me Sasha. Aanka-- is trying-- her best to comfort-- Matthew. This- is the first- time- I've-- ever-- seen-- Matthew-- cry. We'll-- probably-- be in stasis-- by the time you get this message--. Thank- you- again-- for all your help. I look forward-- to meeting-- you in person."
  else
    return "Hey! It's-- me Sasha! LOL! Aanka-- and Matthew-- are dancing-- around-- like- goofballs--! They- are both- so adorable! Only-- this- tiny-- little-- genius-- can make-- a battle-- hardened-- general--- put- on a tiara-- and dance- around-- like a fairy-- princess-- XD------ Anyways, we are heading-- back into-- the chambers--. I hope our welcome-- home- parade-- has fireworks!"
  end
end

def final_message_summary args
  if args.state.scene_history.include? :replied_with_whole_truth
    return {
      background: 'sprites/inside-observatory.png',
      fade: 60,
      player: [31, 11],
      scenes: [[60, 0, 4, 32, :final_decision_side_of_home]],
      storylines: [
        [30, 10, 5, 4, "I can't-- imagine-- what they are feeling-- right now. But at least- they- know everything---, and we can- concentrate-- on rebuilding--- this world-- right- off the bat. I can't-- wait to see the future-- they'll-- help- build."],
      ]
    }
  else
    return {
      background: 'sprites/inside-observatory.png',
      fade: 60,
      player: [31, 11],
      scenes: [[60, 0, 4, 32, :final_decision_side_of_home]],
      storylines: [
        [30, 10, 5, 4, "They all sounded-- so happy. I know- they'll-- be in for a tough- dose- of reality--- when they- arrive. But- at least- they'll-- be around-- all- of us. We'll-- help them- cope."],
      ]
    }
  end
end

Return Of Serenity - storyline_serenity_alive.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline_serenity_alive.rb
def serenity_alive_side_of_home args
  {
    fade: 60,
    background: 'sprites/side-of-home.png',
    player: [16, 13],
    scenes: [
      [52, 24, 11, 5, :serenity_alive_mountain_pass],
    ],
    render_override: :blinking_light_side_of_home_render
  }
end

def serenity_alive_mountain_pass args
  {
    background: 'sprites/mountain-pass-zoomed-out.png',
    player: [4, 4],
    scenes: [
      [18, 47, 5, 5, :serenity_alive_path_to_observatory],
    ],
    storylines: [
      [18, 13, 5, 5, "Hnnnnnnnggg. My legs-- are still sore- from yesterday."]
    ],
    render_override: :blinking_light_mountain_pass_render
  }
end

def serenity_alive_path_to_observatory args
  {
    background: 'sprites/path-to-observatory.png',
    player: [60, 4],
    scenes: [
      [0, 26, 5, 5, :serenity_alive_observatory]
    ],
    storylines: [
      [22, 20, 10, 10, "This spot--, on the mountain, right here, it's-- perfect. This- is where- I'll-- yeet-- the person-- who is playing-- this- prank- on me."]
    ],
    render_override: :blinking_light_path_to_observatory_render
  }
end

def serenity_alive_observatory args
  {
    background: 'sprites/observatory.png',
    player: [60, 2],
    scenes: [
      [28, 39, 4, 10, :serenity_alive_inside_observatory]
    ],
    render_override: :blinking_light_observatory_render
  }
end

def serenity_alive_inside_observatory args
  {
    background: 'sprites/inside-observatory.png',
    player: [60, 2],
    storylines: [],
    scenes: [
      [30, 18, 5, 12, :serenity_alive_inside_mainframe]
    ],
    render_override: :blinking_light_inside_observatory_render
  }
end

def serenity_alive_inside_mainframe args
  {
    background: 'sprites/mainframe.png',
    fade: 60,
    player: [30, 4],
    scenes: [
      [*hotspot_top, :serenity_alive_ship_status],
    ],
    storylines: [
      [22, 45, 17, 4, (serenity_alive_last_reply args)],
      [45, 45,  4, 4, (serenity_alive_current_message args)],
    ]
  }
end

def serenity_alive_ship_status args
  {
    background: 'sprites/serenity.png',
    fade: 60,
    player: [30, 10],
    scenes: [
      [30, 50, 4, 4, :serenity_alive_ship_status_reviewed]
    ],
    storylines: [
      [30,  8, 4, 4, "Serenity? THE--- Mission-- Serenity?! How is that possible? They- are supposed-- to be dead."],
      [30, 10, 4, 4, "I... can't-- believe-- it. I- can access-- Serenity's-- computer? I- guess my \"superpower----\" isn't limited-- by proximity-- to- a machine--."],
      *serenity_alive_shared_ship_status(args)
    ]
  }
end

def serenity_alive_ship_status_reviewed args
  {
    background: 'sprites/serenity.png',
    fade: 60,
    scenes: [
      [*hotspot_bottom, :serenity_alive_time_to_reply]
    ],
    storylines: [
      [0, 62, 62, 3, "Okay. Reviewing-- everything--, it looks- like- I- can- take- the batteries--- from the Stasis--- Chambers--- and- Engine--- to keep- the crew-- alive-- and-- their-- location--- pinpointed---."],
    ]
  }
end

def serenity_alive_time_to_reply args
  decision_graph serenity_alive_current_message(args),
                  "Okay... time to deliver the bad news...",
                  [:replied_to_serenity_alive_firmly, "Firm-- Reply", serenity_alive_firm_reply],
                  [:replied_to_serenity_alive_kindly, "Sugar-- Coated---- Reply", serenity_alive_sugarcoated_reply]
end

def serenity_alive_shared_ship_status args
  [
    *ship_control_hotspot( 0, 50,
                           "Stasis-- Chambers--: Online, All chambers-- are powered. Battery--- Allocation---: 3--- of-- 3--, Hmmm. They don't-- need this to be powered-- right- now. Everyone-- is awake.",
                           nil,
                           nil,
                           nil),
    *ship_control_hotspot(12, 35,
                          "Life- Support--: Offline, Unable--- to- Sustain-- Life. Battery--- Allocation---: 0--- of-- 3---, Okay. That is definitely---- not a good thing.",
                          nil,
                          nil,
                          nil),
    *ship_control_hotspot(24, 20,
                          "Navigation: Offline, Unable--- to- Calculate--- Location. Battery--- Allocation---: 0--- of-- 3---, Whelp. No wonder-- Sasha-- can't-- get- any-- readings. Their- Navigation--- is completely--- offline.",
                          nil,
                          nil,
                          nil),
    *ship_control_hotspot(36, 35,
                          "COMM: Underpowered----, Limited--- to- Text-- Based-- COMM. Battery--- Allocation---: 1--- of-- 3---, It's-- lucky- that- their- COMM---- system was able to survive-- twenty-- years--. Just- barely-- it seems.",
                          nil,
                          nil,
                          nil),
    *ship_control_hotspot(48, 50,
                          "Engine: Online, Full- Control-- Available. Battery--- Allocation---: 3--- of-- 3---, Hmmm. No point of having an engine-- online--, if you don't- know- where you're-- going.",
                          nil,
                          nil,
                          nil)
  ]
end

def serenity_alive_firm_reply
  "Serenity, you are at a distance-- farther-- than- Neptune. All- of the ship's-- systems-- are failing. Please- move the batteries---- from- the Stasis-- Chambers-- over- to- Life-- Support--. I also-- need- you to move-- the batteries---- from- the Engines--- to your Navigation---- System."
end

def serenity_alive_sugarcoated_reply
  "So... you- are- a teeny--- tiny--- bit--- farther-- from Earth- than you think. And you have a teeny--- tiny--- problem-- with your ship. Please-- move the batteries--- from the Stasis--- Chambers--- over to Life--- Support---. I also need you to move the batteries--- from the Engines--- to your- Navigation--- System. Don't-- worry-- Sasha. I'll-- get y'all-- home."
end

def replied_to_serenity_alive_firmly args
  {
    background: 'sprites/inside-observatory.png',
    fade: 60,
    player: [32, 21],
    scenes: [
      [*hotspot_bottom_right, :serenity_alive_path_from_observatory]
    ],
    storylines: [
      [30, 18, 5, 12, "Buffer-- has been set to: #{serenity_alive_firm_reply.quote}"],
      *serenity_alive_reply_completed_shared_hotspots(args),
    ]
  }
end

def replied_to_serenity_alive_kindly args
  {
    background: 'sprites/inside-observatory.png',
    fade: 60,
    player: [32, 21],
    scenes: [
      [*hotspot_bottom_right, :serenity_alive_path_from_observatory]
    ],
    storylines: [
      [30, 18, 5, 12, "Buffer-- has been set to: #{serenity_alive_sugarcoated_reply.quote}"],
      *serenity_alive_reply_completed_shared_hotspots(args),
    ]
  }
end

def serenity_alive_path_from_observatory args
  {
    fade: 60,
    background: 'sprites/path-to-observatory.png',
    player: [4, 21],
    scenes: [
      [*hotspot_bottom_right, :serenity_bio_infront_of_home]
    ],
    storylines: [
      [22, 20, 10, 10, "I'm not sure what's-- worse. Waiting-- for Sasha's-- reply. Or jumping-- off- from- right- here."]
    ]
  }
end

def serenity_alive_reply_completed_shared_hotspots args
  [
    [30, 10, 5, 4, "I guess it wasn't-- a joke- after-- all."],
    [40, 10, 5, 4, "I barely-- remember--- the- history----- of the crew."],
    [50, 10, 5, 4, "It probably--- wouldn't-- hurt- to- refresh-- my memory--."]
  ]
end

def serenity_alive_last_reply args
  if args.state.scene_history.include? :replied_to_introduction_seriously
    return "Buffer--: \"Hello, Who- is sending-- this message--?\""
  else
    return "Buffer--: \"New- phone. Who dis?\""
  end
end

def serenity_alive_current_message args
  if args.state.scene_history.include? :replied_to_introduction_seriously
    "This- is Sasha. The Serenity--- crew-- is out of hibernation---- and ready-- for Earth reentry--. But, it seems like we are having-- trouble-- with our Navigation---- systems. Please advise.".quote
  else
    "LOL! Thanks for the laugh. I needed that. This- is Sasha. The Serenity--- crew-- is out of hibernation---- and ready-- for Earth reentry--. But, it seems like we are having-- trouble-- with our Navigation---- systems. Can you help me out- babe?".quote
  end
end

Return Of Serenity - storyline_serenity_bio.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline_serenity_bio.rb
def serenity_bio_infront_of_home args
  {
    fade: 60,
    background: 'sprites/front-of-home.png',
    player: [54, 23],
    scenes: [
      [44, 34, 8, 14, :serenity_bio_inside_home],
      [0, 3, 3, 22, :serenity_bio_library]
    ]
  }
end

def serenity_bio_inside_home args
  {
    background: 'sprites/inside-home.png',
    player: [34, 4],
    storylines: [
      [34, 4, 4, 4, "I'm--- completely--- exhausted."],
    ],
    scenes: [
      [30, 38, 12, 13, :serenity_bio_restless_sleep],
      [32, 0, 8, 3, :serenity_bio_infront_of_home],
    ]
  }
end

def serenity_bio_restless_sleep args
  {
    fade: 60,
    background: 'sprites/inside-home.png',
    storylines: [
      [32, 38, 10, 13, "I can't-- seem to sleep. I know nothing-- about the- crew-. Maybe- I- should- go read- up- on- them."],
    ],
    scenes: [
      [32, 0, 8, 3, :serenity_bio_infront_of_home],
    ]
  }
end

def serenity_bio_library args
  {
    background: 'sprites/library.png',
    fade: 60,
    player: [30, 7],
    scenes: [
      [21, 35, 3, 18, :serenity_bio_book]
    ]
  }
end

def serenity_bio_book args
  {
    background: 'sprites/book.png',
    fade: 60,
    player: [6, 52],
    storylines: [
      [ 4, 50, 56, 4, "The Title-- Reads: Never-- Forget-- Mission-- Serenity---"],

      [ 4, 38,  8, 8, "Name: Matthew--- R. Sex: Male--- Age-- at-- Departure: 36-----"],
      [14, 38, 46, 8, "Tribute-- Text: Matthew graduated-- Magna-- Cum-- Laude-- from MIT--- with-- a- PHD---- in Aero-- Nautical--- Engineering. He was immensely--- competitive, and had an insatiable---- thirst- for aerial-- battle. From the age of twenty, he remained-- undefeated--- in the Israeli-- Air- Force- \"Blue Flag\" combat-- exercises. By the age of 29--- he had already-- risen through- the ranks, and became-- the Lieutenant--- General--- of Lufwaffe. Matthew-- volenteered-- to- pilot-- Mission-- Serenity. To- this day, his wife- and son- are pillars-- of strength- for us. Rest- in Peace- Matthew, we are sorry-- that- news of the pregancy-- never-- reached- you. Please forgive us."],

      [4,  26,  8, 8, "Name: Aanka--- P. Sex: Female--- Age-- at-- Departure: 9-----"],
      [14, 26, 46, 8, "Tribute-- Text: Aanka--- gratuated--- Magna-- Cum- Laude-- from MIT, at- the- age- of eight, with a- PHD---- in Astro-- Physics. Her-- IQ--- was over 390, the highest-- ever- recorded--- IQ-- in- human-- history. She changed- the landscape-- of Physics-- with her efforts- in- unravelling--- the mysteries--- of- Dark- Matter--. Anka discovered-- the threat- of Halley's-- Comet-- collision--- with Earth. She spear headed-- the global-- effort-- for Misson-- Serenity. Her- multilingual--- address-- to- the world-- brought- us all hope."],

      [4,  14,  8, 8, "Name: Sasha--- N. Sex: Female--- Age-- at-- Departure: 29-----"],
      [14, 14, 46, 8, "Tribute-- Text: Sasha gratuated-- Magna-- Cum- Laude-- from MIT--- with-- a- PHD---- in Computer---- Science----. She-- was-- brilliant--, strong- willed--, and-- a-- stunningly--- beautiful--- woman---. Sasha---- is- the- creator--- of the world's--- first- Ruby--- Quantum-- Machine---. After-- much- critical--- acclaim--, the Quantum-- Computer-- was placed in MIT's---- Museam-- next- to- Richard--- G. and Thomas--- K.'s---- Lisp-- Machine---. Her- engineering--- skills-- were-- paramount--- for Mission--- Serenity's--- success. Humanity-- misses-- you-- dearly,-- Sasha--. Life-- shines-- a dimmer-- light-- now- that- your- angelic- voice-- can never- be heard- again."],
    ],
    scenes: [
      [*hotspot_bottom, :serenity_bio_finally_to_bed]
    ]
  }
end

def serenity_bio_finally_to_bed args
  {
    fade: 60,
    background: 'sprites/inside-home.png',
    player: [35, 3],
    storylines: [
      [34, 4, 4, 4, "Maybe-- I'll-- be able-- to sleep- now..."],
    ],
    scenes: [
      [32, 38, 10, 13, :bad_dream],
    ]
  }
end

def bad_dream args
  {
    fade: 120,
    background: 'sprites/inside-home.png',
    player: [34, 35],
    storylines: [
      [34, 34, 4, 4, "Man. I did not- sleep- well- at all..."],
    ],
    scenes: [
      [32, -1, 8, 3, :bad_dream_observatory]
    ]
  }
end

def bad_dream_observatory args
  {
    background: 'sprites/inside-observatory.png',
    fade: 120,
    player: [51, 12],
    storylines: [
      [50, 10, 4, 4,   "Breathe, Hiro. Just see what's there... everything--- will- be okay."]
    ],
    scenes: [
      [30, 18, 5, 12, :bad_dream_inside_mainframe]
    ],
    render_override: :blinking_light_inside_observatory_render
  }
end

def bad_dream_inside_mainframe args
  {
    player: [32, 4],
    background: 'sprites/mainframe.png',
    fade: 120,
    storylines: [
      [22, 45, 17, 4, (bad_dream_last_reply args)],
    ],
    scenes: [
      [45, 45,  4, 4, :bad_dream_everyone_dead],
    ]
  }
end

def bad_dream_everyone_dead args
  {
    background: 'sprites/mainframe.png',
    storylines: [
      [22, 45, 17, 4, (bad_dream_last_reply args)],
      [45, 45,  4, 4, "Hi-- Hiro. This is Sasha. By the time- you get this- message, chances-- are we will- already-- be- dead. The batteries--- got- damaged-- during-- removal. And- we don't-- have enough-- power-- for Life-- Support. The air-- is- already--- starting-- to taste- bad. It... would- have been- nice... to go- on a date--- with- you-- when-- I- got- back- to Earth. Anyways, good-- bye-- Hiro-- XOXOXO----"],
      [22,  5, 17, 4, "Meh. Whatever, I didn't-- want to save them anyways. What- a pain- in my ass."],
    ],
    scenes: [
      [*hotspot_bottom, :anka_inside_room]
    ]
  }
end

def bad_dream_last_reply args
  if args.state.scene_history.include? :replied_to_serenity_alive_firmly
    return "Buffer--: #{serenity_alive_firm_reply.quote}"
  else
    return "Buffer--: #{serenity_alive_sugarcoated_reply.quote}"
  end
end

Return Of Serenity - storyline_serenity_introduction.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline_serenity_introduction.rb
# decision_graph "Message from Sasha",
#                "I should reply.",
#                [:replied_to_introduction_seriously,  "Reply Seriously", "Who is this?"],
# [:replied_to_introduction_humorously, "Reply Humorously", "New phone who dis?"]
def reply_to_introduction args
  decision_graph  "\"Mission-- control--, your- main- comm-- channels-- seem-- to be down. My apologies-- for- using-- this low- level-- exploit--. What's-- going-- on down there? We are ready-- for reentry--.\" Message--- Timestamp---: 4- hours-- 23--- minutes-- ago--.",
                  "Whoever-- pulled- off this exploit-- knows their stuff. I should reply--.",
                  [:replied_to_introduction_seriously,  "Serious Reply",  "Hello, Who- is sending-- this message--?"],
                  [:replied_to_introduction_humorously, "Humorous Reply", "New phone, who dis?"]
end

def replied_to_introduction_seriously args
  {
    background: 'sprites/inside-observatory.png',
    fade: 60,
    player: [32, 21],
    scenes: [
      *replied_to_introduction_shared_scenes(args)
    ],
    storylines: [
      [30, 18, 5, 12, "Buffer-- has been set to: \"Hello, Who- is sending-- this message--?\""],
      *replied_to_introduction_shared_storylines(args)
    ]
  }
end

def replied_to_introduction_humorously args
  {
    background: 'sprites/inside-observatory.png',
    fade: 60,
    player: [32, 21],
    scenes: [
      *replied_to_introduction_shared_scenes(args)
    ],
    storylines: [
      [30, 18, 5, 12, "Buffer-- has been set to: \"New- phone. Who dis?\""],
      *replied_to_introduction_shared_storylines(args)
    ]
  }
end

def replied_to_introduction_shared_storylines args
  [
    [30, 10, 5, 4, "It's-- going-- to take a while-- for this reply-- to make it's-- way back."],
    [40, 10, 5, 4, "4- hours-- to send a message-- at light speed?! How far away-- is the sender--?"],
    [50, 10, 5, 4, "I know- I've-- read about-- light- speed- travel-- before--. Maybe-- the library--- still has that- poster."]
  ]
end

def replied_to_introduction_shared_scenes args
  [[60, 0, 4, 32, :replied_to_introduction_observatory]]
end

def replied_to_introduction_observatory args
  {
    background: 'sprites/observatory.png',
    player: [28, 39],
    scenes: [
      [60, 0, 4, 32, :replied_to_introduction_path_to_observatory]
    ]
  }
end

def replied_to_introduction_path_to_observatory args
  {
    background: 'sprites/path-to-observatory.png',
    player: [0, 26],
    scenes: [
      [60, 0, 4, 20, :replied_to_introduction_mountain_pass]
    ],
  }
end

def replied_to_introduction_mountain_pass args
  {
    background: 'sprites/mountain-pass-zoomed-out.png',
    player: [21, 48],
    scenes: [
      [0, 0, 15, 4, :replied_to_introduction_side_of_home]
    ],
    storylines: [
      [15, 28, 5, 3, "At least I'm-- getting-- my- exercise-- in- for- today--."]
    ]
  }
end

def replied_to_introduction_side_of_home args
  {
    background: 'sprites/side-of-home.png',
    player: [58, 29],
    scenes: [
      [2, 0, 61, 2, :speed_of_light_front_of_home]
    ],
  }
end

Return Of Serenity - storyline_speed_of_light.rb link

# ./samples/99_genre_rpg_narrative/return_of_serenity/app/storyline_speed_of_light.rb
def speed_of_light_front_of_home args
  {
    background: 'sprites/front-of-home.png',
    player: [54, 23],
    scenes: [
      [44, 34, 8, 14, :speed_of_light_inside_home],
      [0, 3, 3, 22, :speed_of_light_outside_library]
    ]
  }
end

def speed_of_light_inside_home args
  {
    background: 'sprites/inside-home.png',
    player: [35, 4],
    storylines: [
      [30, 38, 12, 13, "Can't- sleep right now. I have to- find- out- why- it took- over-- 4- hours-- to receive-- that message."]
    ],
    scenes: [
      [32, 0, 8, 3, :speed_of_light_front_of_home],
    ]
  }
end

def speed_of_light_outside_library args
  {
    background: 'sprites/outside-library.png',
    player: [55, 19],
    scenes: [
      [49, 39, 6, 10, :speed_of_light_library],
      [61, 11, 3, 20, :speed_of_light_front_of_home]
    ]
  }
end

def speed_of_light_library args
  {
    background: 'sprites/library.png',
    player: [30, 7],
    scenes: [
      [3, 50, 10, 3, :speed_of_light_celestial_bodies_diagram]
    ]
  }
end

def speed_of_light_celestial_bodies_diagram args
  {
    background: 'sprites/planets.png',
    fade: 60,
    player: [30, 3],
    scenes: [
      [56 - 2, 10, 5, 5, :speed_of_light_distance_discovered]
    ],
    storylines: [
      [30, 2, 4, 4, "Here- it is! This is a diagram--- of the solar-- system--. It was printed-- over-- fifty-- years- ago. Geez-- that's-- old."],

      [ 0 - 2, 10, 5, 5, "The label- reads: Sun. The length- of the Astronomical-------- Unit-- (AU), is the distance-- from the Sun- to the Earth. Which is about 150--- million--- kilometers----."],
      [ 7 - 2, 10, 5, 5, "The label- reads: Mercury. Distance from Sun: 0.39AU------------ or- 3----- light-- minutes--."],
      [14 - 2, 10, 5, 5, "The label- reads: Venus. Distance from Sun: 0.72AU------------ or- 6----- light-- minutes--."],
      [21 - 2, 10, 5, 5, "The label- reads: Earth. Distance from Sun: 1.00AU------------ or- 8----- light-- minutes--."],
      [28 - 2, 10, 5, 5, "The label- reads: Mars. Distance from Sun: 1.52AU------------ or- 12----- light-- minutes--."],
      [35 - 2, 10, 5, 5, "The label- reads: Jupiter. Distance from Sun: 5.20AU------------ or- 45----- light-- minutes--."],
      [42 - 2, 10, 5, 5, "The label- reads: Saturn. Distance from Sun: 9.53AU------------ or- 79----- light-- minutes--."],
      [49 - 2, 10, 5, 5, "The label- reads: Uranus. Distance from Sun: 19.81AU------------ or- 159----- light-- minutes--."],
      # [56 - 2, 15, 4, 4, "The label- reads: Neptune. Distance from Sun: 30.05AU------------ or- 4.1----- light-- hours--."],
      [63 - 2, 10, 5, 5, "The label- reads: Pluto. Wait. WTF? Pluto-- isn't-- a planet."],
    ]
  }
end

def speed_of_light_distance_discovered args
  {
    background: 'sprites/planets.png',
    scenes: [
      [13, 0, 44, 3, :speed_of_light_end_of_day]
    ],
    storylines: [
      [ 0 - 2, 10, 5, 5, "The label- reads: Sun. The length- of the Astronomical-------- Unit-- (AU), is the distance-- from the Sun- to the Earth. Which is about 150--- million--- kilometers----."],
      [ 7 - 2, 10, 5, 5, "The label- reads: Mercury. Distance from Sun: 0.39AU------------ or- 3----- light-- minutes--."],
      [14 - 2, 10, 5, 5, "The label- reads: Venus. Distance from Sun: 0.72AU------------ or- 6----- light-- minutes--."],
      [21 - 2, 10, 5, 5, "The label- reads: Earth. Distance from Sun: 1.00AU------------ or- 8----- light-- minutes--."],
      [28 - 2, 10, 5, 5, "The label- reads: Mars. Distance from Sun: 1.52AU------------ or- 12----- light-- minutes--."],
      [35 - 2, 10, 5, 5, "The label- reads: Jupiter. Distance from Sun: 5.20AU------------ or- 45----- light-- minutes--."],
      [42 - 2, 10, 5, 5, "The label- reads: Saturn. Distance from Sun: 9.53AU------------ or- 79----- light-- minutes--."],
      [49 - 2, 10, 5, 5, "The label- reads: Uranus. Distance from Sun: 19.81AU------------ or- 159----- light-- minutes--."],
      [56 - 2, 10, 5, 5, "The label- reads: Neptune. Distance from Sun: 30.05AU------------ or- 4.1----- light-- hours--. What?! The message--- I received-- was from a source-- farther-- than-- Neptune?!"],
      [63 - 2, 10, 5, 5, "The label- reads: Pluto. Dista- Wait... Pluto-- isn't-- a planet. People-- thought- Pluto-- was a planet-- back- then?--"],
    ]
  }
end

def speed_of_light_end_of_day args
  {
    fade: 60,
    background: 'sprites/inside-home.png',
    player: [35, 0],
    storylines: [
      [35, 10, 4, 4, "Wonder-- what the reply-- will be. Who- the hell is contacting--- me from beyond-- Neptune? This- has to be some- kind- of- joke."]
    ],
    scenes: [
      [31, 38, 10, 12, :serenity_alive_side_of_home]
    ]
  }
end

Genre Rpg Roguelike link

Roguelike Starting Point - constants.rb link

# ./samples/99_genre_rpg_roguelike/01_roguelike_starting_point/app/constants.rb
SHOW_LEGEND = true
SOURCE_TILE_SIZE = 16
DESTINATION_TILE_SIZE = 16
TILE_SHEET_SIZE = 256
TILE_R = 0
TILE_G = 0
TILE_B = 0
TILE_A = 255

Roguelike Starting Point - legend.rb link

# ./samples/99_genre_rpg_roguelike/01_roguelike_starting_point/app/legend.rb
def tick_legend args
  return unless SHOW_LEGEND

  legend_padding = 16
  legend_x = 1280 - TILE_SHEET_SIZE - legend_padding
  legend_y =  720 - TILE_SHEET_SIZE - legend_padding
  tile_sheet_sprite = [legend_x,
                       legend_y,
                       TILE_SHEET_SIZE,
                       TILE_SHEET_SIZE,
                       'sprites/simple-mood-16x16.png', 0,
                       TILE_A,
                       TILE_R,
                       TILE_G,
                       TILE_B]

  if args.inputs.mouse.point.inside_rect? tile_sheet_sprite
    mouse_row = args.inputs.mouse.point.y.idiv(SOURCE_TILE_SIZE)
    tile_row = 15 - (mouse_row - legend_y.idiv(SOURCE_TILE_SIZE))

    mouse_col = args.inputs.mouse.point.x.idiv(SOURCE_TILE_SIZE)
    tile_col = (mouse_col - legend_x.idiv(SOURCE_TILE_SIZE))

    args.outputs.primitives << [legend_x - legend_padding * 2,
                                mouse_row * SOURCE_TILE_SIZE, 256 + legend_padding * 2, 16, 128, 128, 128, 64].solid

    args.outputs.primitives << [mouse_col * SOURCE_TILE_SIZE,
                                legend_y - legend_padding * 2, 16, 256 + legend_padding * 2, 128, 128, 128, 64].solid

    sprite_key = sprite_lookup.find { |k, v| v == [tile_row, tile_col] }
    if sprite_key
      member_name, _ = sprite_key
      member_name = member_name_as_code member_name
      args.outputs.labels << [660, 70, "# CODE SAMPLE (place in the tick_game method located in main.rb)", -1, 0]
      args.outputs.labels << [660, 50, "#                                    GRID_X, GRID_Y, TILE_KEY", -1, 0]
      args.outputs.labels << [660, 30, "args.outputs.sprites << tile_in_game(     5,      6, #{member_name}    )", -1, 0]
    else
      args.outputs.labels << [660, 50, "Tile [#{tile_row}, #{tile_col}] not found. Add a key and value to app/sprite_lookup.rb:", -1, 0]
      args.outputs.labels << [660, 30, "{ \"some_string\" => [#{tile_row}, #{tile_col}] } OR { some_symbol: [#{tile_row}, #{tile_col}] }.", -1, 0]
    end

  end

  # render the sprite in the top right with a padding to the top and right so it's
  # not flush against the edge
  args.outputs.sprites << tile_sheet_sprite

  # carefully place some ascii arrows to show the legend labels
  args.outputs.labels  <<  [895, 707, "ROW --->"]
  args.outputs.labels  <<  [943, 412, "       ^"]
  args.outputs.labels  <<  [943, 412, "       |"]
  args.outputs.labels  <<  [943, 394, "COL ---+"]

  # use the tile sheet to print out row and column numbers
  args.outputs.sprites << 16.map_with_index do |i|
    sprite_key = i % 10
    [
      tile(1280 - TILE_SHEET_SIZE - legend_padding * 2 - SOURCE_TILE_SIZE,
            720 - legend_padding * 2 - (SOURCE_TILE_SIZE * i),
            sprite(sprite_key)),
      tile(1280 - TILE_SHEET_SIZE - SOURCE_TILE_SIZE + (SOURCE_TILE_SIZE * i),
            720 - TILE_SHEET_SIZE - legend_padding * 3, sprite(sprite_key))
    ]
  end
end

Roguelike Starting Point - main.rb link

# ./samples/99_genre_rpg_roguelike/01_roguelike_starting_point/app/main.rb
require 'app/constants.rb'
require 'app/sprite_lookup.rb'
require 'app/legend.rb'

def tick args
  tick_game args
  tick_legend args
end

def tick_game args
  # setup the grid
  args.state.grid.padding = 104
  args.state.grid.size = 512

  # set up your game
  # initialize the game/game defaults. ||= means that you only initialize it if
  # the value isn't alread initialized
  args.state.player.x ||= 0
  args.state.player.y ||= 0

  args.state.enemies ||= [
    { x: 10, y: 10, type: :goblin, tile_key: :G },
    { x: 15, y: 30, type: :rat,    tile_key: :R }
  ]

  args.state.info_message ||= "Use arrow keys to move around."

  # handle keyboard input
  # keyboard input (arrow keys to move player)
  new_player_x = args.state.player.x
  new_player_y = args.state.player.y
  player_direction = ""
  player_moved = false
  if args.inputs.keyboard.key_down.up
    new_player_y += 1
    player_direction = "north"
    player_moved = true
  elsif args.inputs.keyboard.key_down.down
    new_player_y -= 1
    player_direction = "south"
    player_moved = true
  elsif args.inputs.keyboard.key_down.right
    new_player_x += 1
    player_direction = "east"
    player_moved = true
  elsif args.inputs.keyboard.key_down.left
    new_player_x -= 1
    player_direction = "west"
    player_moved = true
  end

  #handle game logic
  # determine if there is an enemy on that square,
  # if so, don't let the player move there
  if player_moved
    found_enemy = args.state.enemies.find do |e|
      e[:x] == new_player_x && e[:y] == new_player_y
    end

    if !found_enemy
      args.state.player.x = new_player_x
      args.state.player.y = new_player_y
      args.state.info_message = "You moved #{player_direction}."
    else
      args.state.info_message = "You cannot move into a square an enemy occupies."
    end
  end

  args.outputs.sprites << tile_in_game(args.state.player.x,
                                       args.state.player.y, '@')

  # render game
  # render enemies at locations
  args.outputs.sprites << args.state.enemies.map do |e|
    tile_in_game(e[:x], e[:y], e[:tile_key])
  end

  # render the border
  border_x = args.state.grid.padding - DESTINATION_TILE_SIZE
  border_y = args.state.grid.padding - DESTINATION_TILE_SIZE
  border_size = args.state.grid.size + DESTINATION_TILE_SIZE * 2

  args.outputs.borders << [border_x,
                           border_y,
                           border_size,
                           border_size]

  # render label stuff
  args.outputs.labels << [border_x, border_y - 10, "Current player location is: #{args.state.player.x}, #{args.state.player.y}"]
  args.outputs.labels << [border_x, border_y + 25 + border_size, args.state.info_message]
end

def tile_in_game x, y, tile_key
  tile($gtk.args.state.grid.padding + x * DESTINATION_TILE_SIZE,
       $gtk.args.state.grid.padding + y * DESTINATION_TILE_SIZE,
       tile_key)
end

Roguelike Starting Point - sprite_lookup.rb link

# ./samples/99_genre_rpg_roguelike/01_roguelike_starting_point/app/sprite_lookup.rb
def sprite_lookup
  {
    0 => [3, 0],
    1 => [3, 1],
    2 => [3, 2],
    3 => [3, 3],
    4 => [3, 4],
    5 => [3, 5],
    6 => [3, 6],
    7 => [3, 7],
    8 => [3, 8],
    9 => [3, 9],
    '@' => [4, 0],
    A: [ 4,  1],
    B: [ 4,  2],
    C: [ 4,  3],
    D: [ 4,  4],
    E: [ 4,  5],
    F: [ 4,  6],
    G: [ 4,  7],
    H: [ 4,  8],
    I: [ 4,  9],
    J: [ 4, 10],
    K: [ 4, 11],
    L: [ 4, 12],
    M: [ 4, 13],
    N: [ 4, 14],
    O: [ 4, 15],
    P: [ 5,  0],
    Q: [ 5,  1],
    R: [ 5,  2],
    S: [ 5,  3],
    T: [ 5,  4],
    U: [ 5,  5],
    V: [ 5,  6],
    W: [ 5,  7],
    X: [ 5,  8],
    Y: [ 5,  9],
    Z: [ 5, 10],
    a: [ 6,  1],
    b: [ 6,  2],
    c: [ 6,  3],
    d: [ 6,  4],
    e: [ 6,  5],
    f: [ 6,  6],
    g: [ 6,  7],
    h: [ 6,  8],
    i: [ 6,  9],
    j: [ 6, 10],
    k: [ 6, 11],
    l: [ 6, 12],
    m: [ 6, 13],
    n: [ 6, 14],
    o: [ 6, 15],
    p: [ 7,  0],
    q: [ 7,  1],
    r: [ 7,  2],
    s: [ 7,  3],
    t: [ 7,  4],
    u: [ 7,  5],
    v: [ 7,  6],
    w: [ 7,  7],
    x: [ 7,  8],
    y: [ 7,  9],
    z: [ 7, 10],
    '|' => [ 7, 12]
  }
end

def sprite key
  $gtk.args.state.reserved.sprite_lookup[key]
end

def member_name_as_code raw_member_name
  if raw_member_name.is_a? Symbol
    ":#{raw_member_name}"
  elsif raw_member_name.is_a? String
    "'#{raw_member_name}'"
  elsif raw_member_name.is_a? Fixnum
    "#{raw_member_name}"
  else
    "UNKNOWN: #{raw_member_name}"
  end
end

def tile x, y, tile_row_column_or_key
  tile_extended x, y, DESTINATION_TILE_SIZE, DESTINATION_TILE_SIZE, TILE_R, TILE_G, TILE_B, TILE_A, tile_row_column_or_key
end

def tile_extended x, y, w, h, r, g, b, a, tile_row_column_or_key
  row_or_key, column = tile_row_column_or_key
  if !column
    row, column = sprite row_or_key
  else
    row, column = row_or_key, column
  end

  if !row
    member_name = member_name_as_code tile_row_column_or_key
    raise "Unabled to find a sprite for #{member_name}. Make sure the value exists in app/sprite_lookup.rb."
  end

  # Sprite provided by Rogue Yun
  # http://www.bay12forums.com/smf/index.php?topic=144897.0
  # License: Public Domain

  {
    x: x,
    y: y,
    w: w,
    h: h,
    tile_x: column * 16,
    tile_y: (row * 16),
    tile_w: 16,
    tile_h: 16,
    r: r,
    g: g,
    b: b,
    a: a,
    path: 'sprites/simple-mood-16x16.png'
  }
end

$gtk.args.state.reserved.sprite_lookup = sprite_lookup

Roguelike Line Of Sight - main.rb link

# ./samples/99_genre_rpg_roguelike/02_roguelike_line_of_sight/app/main.rb
=begin

 APIs listing that haven't been encountered in previous sample apps:

 - lambda: A way to define a block and its parameters with special syntax.
   For example, the syntax of lambda looks like this:
   my_lambda = -> { puts "This is my lambda" }

 Reminders:
 - args.outputs.labels: An array. The values generate a label.
   The parameters are [X, Y, TEXT, SIZE, ALIGNMENT, RED, GREEN, BLUE, ALPHA, FONT STYLE]
   For more information about labels, go to mygame/documentation/02-labels.

 - ARRAY#inside_rect?: Returns whether or not the point is inside a rect.

 - product: Returns an array of all combinations of elements from all arrays.

 - find: Finds all elements of a collection that meet requirements.

 - abs: Returns the absolute value.

=end

# This sample app allows the player to move around in the dungeon, which becomes more or less visible
# depending on the player's location, and also has enemies.

class Game
  attr_accessor :args, :state, :inputs, :outputs, :grid

  # Calls all the methods needed for the game to run properly.
  def tick
    defaults
    render_canvas
    render_dungeon
    render_player
    render_enemies
    print_cell_coordinates
    calc_canvas
    input_move
    input_click_map
  end

  # Sets default values and initializes variables
  def defaults
    outputs.background_color = [0, 0, 0] # black background

    # Initializes empty canvas, dungeon, and enemies collections.
    state.canvas   ||= []
    state.dungeon  ||= []
    state.enemies  ||= []

    # If state.area doesn't have value, load_area_one and derive_dungeon_from_area methods are called
    if !state.area
      load_area_one
      derive_dungeon_from_area

      # Changing these values will change the position of player
      state.x = 7
      state.y = 5

      # Creates new enemies, sets their values, and adds them to the enemies collection.
      state.enemies << state.new_entity(:enemy) do |e| # declares each enemy as new entity
        e.x           = 13 # position
        e.y           = 5
        e.previous_hp = 3
        e.hp          = 3
        e.max_hp      = 3
        e.is_dead     = false # the enemy is alive
      end

      update_line_of_sight # updates line of sight by adding newly visible cells
    end
  end

  # Adds elements into the state.area collection
  # The dungeon is derived using the coordinates of this collection
  def load_area_one
    state.area ||= []
    state.area << [8, 6]
    state.area << [7, 6]
    state.area << [7, 7]
    state.area << [8, 9]
    state.area << [7, 8]
    state.area << [7, 9]
    state.area << [6, 4]
    state.area << [7, 3]
    state.area << [7, 4]
    state.area << [6, 5]
    state.area << [7, 5]
    state.area << [8, 5]
    state.area << [8, 4]
    state.area << [1, 1]
    state.area << [0, 1]
    state.area << [0, 2]
    state.area << [1, 2]
    state.area << [2, 2]
    state.area << [2, 1]
    state.area << [2, 3]
    state.area << [1, 3]
    state.area << [1, 4]
    state.area << [2, 4]
    state.area << [2, 5]
    state.area << [1, 5]
    state.area << [2, 6]
    state.area << [3, 6]
    state.area << [4, 6]
    state.area << [4, 7]
    state.area << [4, 8]
    state.area << [5, 8]
    state.area << [5, 9]
    state.area << [6, 9]
    state.area << [7, 10]
    state.area << [7, 11]
    state.area << [7, 12]
    state.area << [7, 12]
    state.area << [7, 13]
    state.area << [8, 13]
    state.area << [9, 13]
    state.area << [10, 13]
    state.area << [11, 13]
    state.area << [12, 13]
    state.area << [12, 12]
    state.area << [8, 12]
    state.area << [9, 12]
    state.area << [10, 12]
    state.area << [11, 12]
    state.area << [12, 11]
    state.area << [13, 11]
    state.area << [13, 10]
    state.area << [13, 9]
    state.area << [13, 8]
    state.area << [13, 7]
    state.area << [13, 6]
    state.area << [12, 6]
    state.area << [14, 6]
    state.area << [14, 5]
    state.area << [13, 5]
    state.area << [12, 5]
    state.area << [12, 4]
    state.area << [13, 4]
    state.area << [14, 4]
    state.area << [1, 6]
    state.area << [6, 6]
  end

  # Starts with an empty dungeon collection, and adds dungeon cells into it.
  def derive_dungeon_from_area
    state.dungeon = [] # starts as empty collection

    state.area.each do |a| # for each element of the area collection
      state.dungeon << state.new_entity(:dungeon_cell) do |d| # declares each dungeon cell as new entity
        d.x = a.x # dungeon cell position using coordinates from area
        d.y = a.y
        d.is_visible = false # cell is not visible
        d.alpha = 0 # not transparent at all
        d.border = [left_margin   + a.x * grid_size,
                    bottom_margin + a.y * grid_size,
                    grid_size,
                    grid_size,
                    *blue,
                    255] # sets border definition for dungeon cell
        d # returns dungeon cell
      end
    end
  end

  def left_margin
    40  # sets left margin
  end

  def bottom_margin
    60 # sets bottom margin
  end

  def grid_size
    40 # sets size of grid square
  end

  # Updates the line of sight by calling the thick_line_of_sight method and
  # adding dungeon cells to the newly_visible collection
  def update_line_of_sight
    variations = [-1, 0, 1]
    # creates collection of newly visible dungeon cells
    newly_visible = variations.product(variations).flat_map do |rise, run| # combo of all elements
      thick_line_of_sight state.x, state.y, rise, run, 15, # calls thick_line_of_sight method
                          lambda { |x, y| dungeon_cell_exists? x, y } # checks whether or not cell exists
    end.uniq# removes duplicates

    state.dungeon.each do |d| # perform action on each element of dungeons collection
      d.is_visible = newly_visible.find { |v| v.x == d.x && v.y == d.y } # finds match inside newly_visible collection
    end
  end

  #Returns a boolean value
  def dungeon_cell_exists? x, y
    # Finds cell coordinates inside dungeon collection to determine if dungeon cell exists
    state.dungeon.find { |d| d.x == x && d.y == y }
  end

  # Calls line_of_sight method to add elements to result collection
  def thick_line_of_sight start_x, start_y, rise, run, distance, cell_exists_lambda
    result = []
    result += line_of_sight start_x, start_y, rise, run, distance, cell_exists_lambda
    result += line_of_sight start_x - 1, start_y, rise, run, distance, cell_exists_lambda # one left
    result += line_of_sight start_x + 1, start_y, rise, run, distance, cell_exists_lambda # one right
    result
  end

  # Adds points to the result collection to create the player's line of sight
  def line_of_sight start_x, start_y, rise, run, distance, cell_exists_lambda
    result = [] # starts as empty collection
    points = points_on_line start_x, start_y, rise, run, distance # calls points_on_line method
    points.each do |p| # for each point in collection
      if cell_exists_lambda.call(p.x, p.y) # if the cell exists
        result << p # add it to result collection
      else # if cell does not exist
        return result # return result collection as it is
      end
    end

    result # return result collection
  end

  # Finds the coordinates of the points on the line by performing calculations
  def points_on_line start_x, start_y, rise, run, distance
    distance.map do |i| # perform an action
      [start_x + run * i, start_y + rise * i] # definition of point
    end
  end

  def render_canvas
    return
    outputs.borders << state.canvas.map do |c| # on each element of canvas collection
      c.border # outputs border
    end
  end

  # Outputs the dungeon cells.
  def render_dungeon
    outputs.solids << [0, 0, grid.w, grid.h] # outputs black background for grid

    # Sets the alpha value (opacity) for each dungeon cell and calls the cell_border method.
    outputs.borders << state.dungeon.map do |d| # for each element in dungeon collection
      d.alpha += if d.is_visible # if cell is visible
                 255.fdiv(30) # increment opacity (transparency)
               else # if cell is not visible
                 255.fdiv(600) * -1 # decrease opacity
               end
      d.alpha = d.alpha.cap_min_max(0, 255)
      cell_border d.x, d.y, [*blue, d.alpha] # sets blue border using alpha value
    end.reject_nil
  end

  # Sets definition of a cell border using the parameters
  def cell_border x, y, color = nil
    [left_margin   + x * grid_size,
    bottom_margin + y * grid_size,
    grid_size,
    grid_size,
    *color]
  end

  # Sets the values for the player and outputs it as a label
  def render_player
    outputs.labels << [grid_x(state.x) + 20, # positions "@" text in center of grid square
                     grid_y(state.y) + 35,
                     "@", # player is represented by a white "@" character
                     1, 1, *white]
  end

  def grid_x x
    left_margin + x * grid_size # positions horizontally on grid
  end

  def grid_y y
    bottom_margin + y * grid_size # positions vertically on grid
  end

  # Outputs enemies onto the screen.
  def render_enemies
    state.enemies.map do |e| # for each enemy in the collection
      alpha = 255 # set opacity (full transparency)

      # Outputs an enemy using a label.
      outputs.labels << [
                   left_margin + 20 +  e.x * grid_size, # positions enemy's "r" text in center of grid square
                   bottom_margin + 35 + e.y * grid_size,
                   "r", # enemy's text
                   1, 1, *white, alpha]

      # Creates a red border around an enemy.
      outputs.borders << [grid_x(e.x), grid_y(e.y), grid_size, grid_size, *red]
    end
  end

  #White labels are output for the cell coordinates of each element in the dungeon collection.
  def print_cell_coordinates
    return unless state.debug
    state.dungeon.each do |d|
      outputs.labels << [grid_x(d.x) + 2,
                         grid_y(d.y) - 2,
                         "#{d.x},#{d.y}",
                         -2, 0, *white]
    end
  end

  # Adds new elements into the canvas collection and sets their values.
  def calc_canvas
    return if state.canvas.length > 0 # return if canvas collection has at least one element
    15.times do |x| # 15 times perform an action
      15.times do |y|
        state.canvas << state.new_entity(:canvas) do |c| # declare canvas element as new entity
          c.x = x # set position
          c.y = y
          c.border = [left_margin   + x * grid_size,
                      bottom_margin + y * grid_size,
                      grid_size,
                      grid_size,
                      *white, 30] # sets border definition
        end
      end
    end
  end

  # Updates x and y values of the player, and updates player's line of sight
  def input_move
    x, y, x_diff, y_diff = input_target_cell

    return unless dungeon_cell_exists? x, y # player can't move there if a dungeon cell doesn't exist in that location
    return if enemy_at x, y # player can't move there if there is an enemy in that location

    state.x += x_diff # increments x by x_diff (so player moves left or right)
    state.y += y_diff # same with y and y_diff ( so player moves up or down)
    update_line_of_sight # updates visible cells
  end

  def enemy_at x, y
    # Finds if coordinates exist in enemies collection and enemy is not dead
    state.enemies.find { |e| e.x == x && e.y == y && !e.is_dead }
  end

  #M oves the user based on their keyboard input and sets values for target cell
  def input_target_cell
    if inputs.keyboard.key_down.up # if "up" key is in "down" state
      [state.x, state.y + 1,  0,  1] # user moves up
    elsif inputs.keyboard.key_down.down # if "down" key is pressed
      [state.x, state.y - 1,  0, -1] # user moves down
    elsif inputs.keyboard.key_down.left # if "left" key is pressed
      [state.x - 1, state.y, -1,  0] # user moves left
    elsif inputs.keyboard.key_down.right # if "right" key is pressed
      [state.x + 1, state.y,  1,  0] # user moves right
    else
      nil  # otherwise, empty
    end
  end

  # Goes through the canvas collection to find if the mouse was clicked inside of the borders of an element.
  def input_click_map
    return unless inputs.mouse.click # return unless the mouse is clicked
    canvas_entry = state.canvas.find do |c| # find element from canvas collection that meets requirements
      inputs.mouse.click.inside_rect? c.border # find border that mouse was clicked inside of
    end
    puts canvas_entry # prints canvas_entry value
  end

  # Sets the definition of a label using the parameters.
  def label text, x, y, color = nil
    color ||= white # color is initialized to white
    [x, y, text, 1, 1, *color] # sets label definition
  end

  def green
    [60, 200, 100] # sets color saturation to shade of green
  end

  def blue
    [50, 50, 210] # sets color saturation to shade of blue
  end

  def white
    [255, 255, 255] # sets color saturation to white
  end

  def red
    [230, 80, 80] # sets color saturation to shade of red
  end

  def orange
    [255, 80, 60] # sets color saturation to shade of orange
  end

  def pink
    [255, 0, 200] # sets color saturation to shade of pink
  end

  def gray
    [75, 75, 75] # sets color saturation to shade of gray
  end

  # Recolors the border using the parameters.
  def recolor_border border, r, g, b
    border[4] = r
    border[5] = g
    border[6] = b
    border
  end

  # Returns a boolean value.
  def visible? cell
    # finds cell's coordinates inside visible_cells collections to determine if cell is visible
    state.visible_cells.find { |c| c.x == cell.x && c.y == cell.y}
  end

  # Exports dungeon by printing dungeon cell coordinates
  def export_dungeon
    state.dungeon.each do |d| # on each element of dungeon collection
      puts "state.dungeon << [#{d.x}, #{d.y}]" # prints cell coordinates
    end
  end

  def distance_to_cell cell
    distance_to state.x, cell.x, state.y, cell.y # calls distance_to method
  end

  def distance_to from_x, x, from_y, y
    (from_x - x).abs + (from_y - y).abs # finds distance between two cells using coordinates
  end
end

$game = Game.new

def tick args
  $game.args    = args
  $game.state   = args.state
  $game.inputs  = args.inputs
  $game.outputs = args.outputs
  $game.grid    = args.grid
  $game.tick
end

Genre Rpg Tactical link

Hexagonal Grid - main.rb link

# ./samples/99_genre_rpg_tactical/hexagonal_grid/app/main.rb
class HexagonTileGame
  attr_gtk

  def defaults
    state.tile_scale      = 1.3
    state.tile_size       = 80
    state.tile_w          = Math.sqrt(3) * state.tile_size.half
    state.tile_h          = state.tile_size * 3/4
    state.tiles_x_count   = 1280.idiv(state.tile_w) - 1
    state.tiles_y_count   = 720.idiv(state.tile_h) - 1
    state.world_width_px  = state.tiles_x_count * state.tile_w
    state.world_height_px = state.tiles_y_count * state.tile_h
    state.world_x_offset  = (1280 - state.world_width_px).half
    state.world_y_offset  = (720 - state.world_height_px).half
    state.tiles         ||= state.tiles_x_count.map_with_ys(state.tiles_y_count) do |ordinal_x, ordinal_y|
      {
        ordinal_x: ordinal_x,
        ordinal_y: ordinal_y,
        offset_x: (ordinal_y.even?) ?
                  (state.world_x_offset + state.tile_w.half.half) :
                  (state.world_x_offset - state.tile_w.half.half),
        offset_y: state.world_y_offset,
        w: state.tile_w,
        h: state.tile_h,
        type: :blank,
        path: "sprites/hexagon-gray.png",
        a: 20
      }.associate do |h|
        h.merge(x: h[:offset_x] + h[:ordinal_x] * h[:w],
                y: h[:offset_y] + h[:ordinal_y] * h[:h]).scale_rect(state.tile_scale)
      end.associate do |h|
        h.merge(center: {
                  x: h[:x] + h[:w].half,
                  y: h[:y] + h[:h].half
                }, radius: [h[:w].half, h[:h].half].max)
      end
    end
  end

  def input
    if inputs.click
      tile = state.tiles.find { |t| inputs.click.point_inside_circle? t[:center], t[:radius] }
      if tile
        tile[:a] = 255
        tile[:path] = "sprites/hexagon-black.png"
      end
    end
  end

  def tick
    defaults
    input
    render
  end

  def render
    outputs.sprites << state.tiles
  end
end

$game = HexagonTileGame.new

def tick args
  $game.args = args
  $game.tick
end

$gtk.reset

Isometric Grid - main.rb link

# ./samples/99_genre_rpg_tactical/isometric_grid/app/main.rb
class Isometric
    attr_accessor :grid, :inputs, :state, :outputs

    def tick
        defaults
        render
        calc
        process_inputs
    end

    def defaults
        state.quantity              ||= 6                                                        #Size of grid
        state.tileSize              ||= [262 / 2, 194 / 2]                                       #width and heigth of orange tiles
        state.tileGrid              ||= []                                                       #Holds ordering of tiles
        state.currentSpriteLocation ||= -1                                                       #Current Sprite hovering location
        state.tileCords             ||= []                                                       #Physical, rendering cordinates
        state.initCords             ||= [640 - (state.quantity / 2 * state.tileSize[0]), 330]    #Location of tile (0, 0)
        state.sideSize              ||= [state.tileSize[0] / 2, 242 / 2]                         #Purple & green cube face size
        state.mode                  ||= :delete                                                  #Switches between :delete and :insert
        state.spriteSelection       ||= [['river',    0, 0, 262 / 2, 194 / 2],
                                         ['mountain', 0, 0, 262 / 2, 245 / 2],
                                         ['ocean',    0, 0, 262 / 2, 194 / 2]]             #Storage for sprite information
                                                                                           #['name', deltaX, deltaY, sizeW, sizeH]
                                                                                           #^delta refers to distance from tile cords

        #Orders tiles based on tile placement and fancy math. Very left: 0,0. Very bottom: quantity-1, 0, etc
        if state.tileGrid == []
            tempX = 0
            tempY = 0
            tempLeft = false
            tempRight = false
            count = 0
            (state.quantity * state.quantity).times do
                if tempY == 0
                    tempLeft = true
                end
                if tempX == (state.quantity - 1)
                    tempRight = true
                end
                state.tileGrid.push([tempX, tempY, true, tempLeft, tempRight, count])
                    #orderX, orderY, exists?, leftSide, rightSide, order
                tempX += 1
                if tempX == state.quantity
                    tempX = 0
                    tempY += 1
                end
                tempLeft = false
                tempRight = false
                count += 1
            end
        end

        #Calculates physical cordinates for tiles
        if state.tileCords == []
            state.tileCords = state.tileGrid.map do
                |val|
                x = (state.initCords[0]) + ((val[0] + val[1]) * state.tileSize[0] / 2)
                y = (state.initCords[1]) + (-1 * val[0] * state.tileSize[1] / 2) + (val[1] * state.tileSize[1] / 2)
                [x, y, val[2], val[3], val[4], val[5], -1] #-1 represents sprite on top of tile. -1 for now
            end
        end

    end

    def render
        renderBackground
        renderLeft
        renderRight
        renderTiles
        renderObjects
        renderLabels
    end

    def renderBackground
        outputs.solids << [0, 0, 1280, 720, 0, 0, 0]   #Background color
    end

    def renderLeft
        #Shows the pink left cube face
        outputs.sprites << state.tileCords.map do
            |val|
            if val[2] == true && val[3] == true       #Checks if the tile exists and right face needs to be rendered
                [val[0], val[1] + (state.tileSize[1] / 2) - state.sideSize[1], state.sideSize[0],
                state.sideSize[1], 'sprites/leftSide.png']
            end
        end
    end

    def renderRight
        #Shows the green right cube face
        outputs.sprites << state.tileCords.map do
            |val|
            if val[2] == true && val[4] == true        #Checks if it exists & checks if right face needs to be rendered
                [val[0] + state.tileSize[0] / 2, val[1] + (state.tileSize[1] / 2) - state.sideSize[1], state.sideSize[0],
                state.sideSize[1], 'sprites/rightSide.png']
            end
        end
    end

    def renderTiles
        #Shows the tile itself. Important that it's rendered after the two above!
        outputs.sprites << state.tileCords.map do
            |val|
            if val[2] == true     #Chcekcs if tile needs to be rendered
              if val[5] == state.currentSpriteLocation
                [val[0], val[1], state.tileSize[0], state.tileSize[1], 'sprites/selectedTile.png']
              else
                [val[0], val[1], state.tileSize[0], state.tileSize[1], 'sprites/tile.png']
              end
            end
        end
    end

    def renderObjects
        #Renders the sprites on top of the tiles. Order of rendering: top corner to right corner and cascade down until left corner
        #to bottom corner.
        a = (state.quantity * state.quantity) - state.quantity
        iter = 0
        loop do
            if state.tileCords[a][2] == true && state.tileCords[a][6] != -1
                outputs.sprites << [state.tileCords[a][0] + state.spriteSelection[state.tileCords[a][6]][1],
                                    state.tileCords[a][1] + state.spriteSelection[state.tileCords[a][6]][2],
                                    state.spriteSelection[state.tileCords[a][6]][3], state.spriteSelection[state.tileCords[a][6]][4],
                                    'sprites/' + state.spriteSelection[state.tileCords[a][6]][0] + '.png']
            end
            iter += 1
            a    += 1
            a -= state.quantity * 2 if iter == state.quantity
            iter = 0                if iter == state.quantity
            break if a < 0
        end
    end

    def renderLabels
        #Labels
        outputs.labels << [50, 680, 'Click to delete!',             5, 0, 255, 255, 255, 255] if state.mode == :delete
        outputs.labels << [50, 640, 'Press \'i\' for insert mode!', 5, 0, 255, 255, 255, 255] if state.mode == :delete
        outputs.labels << [50, 680, 'Click to insert!',             5, 0, 255, 255, 255, 255] if state.mode == :insert
        outputs.labels << [50, 640, 'Press \'d\' for delete mode!', 5, 0, 255, 255, 255, 255] if state.mode == :insert
    end

    def calc
        calcCurrentHover
    end

    def calcCurrentHover
        #This determines what tile the mouse is hovering (or last hovering) over
        x = inputs.mouse.position.x
        y = inputs.mouse.position.y
        m = (state.tileSize[1] / state.tileSize[0])   #slope
        state.tileCords.map do
            |val|
            #Conditions that makes runtime faster. Checks if the mouse click was between tile dimensions (rectangle collision)
            next unless val[0] < x && x < val[0] + state.tileSize[0]
            next unless val[1] < y && y < val[1] + state.tileSize[1]
            next unless val[2] == true
            tempBool = false
            if x == val[0] + (state.tileSize[0] / 2)
                #The height of a diamond is the height of the diamond, so if x equals that exact point, it must be inside the diamond
                tempBool = true
            elsif x < state.tileSize[0] / 2 + val[0]
                #Uses y = (m) * (x - x1) + y1 to determine the y values for the two diamond lines on the left half of diamond
                tempY1 =      (m * (x - val[0])) + val[1] + (state.tileSize[1] / 2)
                tempY2 = (-1 * m * (x - val[0])) + val[1] + (state.tileSize[1] / 2)
                #Checks to see if the mouse click y value is between those temp y values
                tempBool = true if y < tempY1 && y > tempY2
            elsif x > state.tileSize[0] / 2 + val[0]
                #Uses y = (m) * (x - x1) + y1 to determine the y values for the two diamond lines on the right half of diamond
                tempY1 =      (m * (x - val[0] - (state.tileSize[0] / 2))) + val[1]
                tempY2 = (-1 * m * (x - val[0] - (state.tileSize[0] / 2))) + val[1] + state.tileSize[1]
                #Checks to see if the mouse click y value is between those temp y values
                tempBool = true if y > tempY1 && y < tempY2
            end

            if tempBool == true
                state.currentSpriteLocation = val[5]         #Current sprite location set to the order value
            end
        end
    end

    def process_inputs
        #Makes development much faster and easier
        if inputs.keyboard.key_up.r
            $dragon.reset
        end
        checkTileSelected
        switchModes
    end

    def checkTileSelected
        if inputs.mouse.down
            x = inputs.mouse.down.point.x
            y = inputs.mouse.down.point.y
            m = (state.tileSize[1] / state.tileSize[0])   #slope
            state.tileCords.map do
                |val|
                #Conditions that makes runtime faster. Checks if the mouse click was between tile dimensions (rectangle collision)
                next unless val[0] < x && x < val[0] + state.tileSize[0]
                next unless val[1] < y && y < val[1] + state.tileSize[1]
                next unless val[2] == true
                tempBool = false
                if x == val[0] + (state.tileSize[0] / 2)
                    #The height of a diamond is the height of the diamond, so if x equals that exact point, it must be inside the diamond
                    tempBool = true
                elsif x < state.tileSize[0] / 2 + val[0]
                    #Uses y = (m) * (x - x1) + y1 to determine the y values for the two diamond lines on the left half of diamond
                    tempY1 =      (m * (x - val[0])) + val[1] + (state.tileSize[1] / 2)
                    tempY2 = (-1 * m * (x - val[0])) + val[1] + (state.tileSize[1] / 2)
                    #Checks to see if the mouse click y value is between those temp y values
                    tempBool = true if y < tempY1 && y > tempY2
                elsif x > state.tileSize[0] / 2 + val[0]
                    #Uses y = (m) * (x - x1) + y1 to determine the y values for the two diamond lines on the right half of diamond
                    tempY1 =      (m * (x - val[0] - (state.tileSize[0] / 2))) + val[1]
                    tempY2 = (-1 * m * (x - val[0] - (state.tileSize[0] / 2))) + val[1] + state.tileSize[1]
                    #Checks to see if the mouse click y value is between those temp y values
                    tempBool = true if y > tempY1 && y < tempY2
                end

                if tempBool == true
                    if state.mode == :delete
                        val[2] = false
                        state.tileGrid[val[5]][2]  = false      #Unnecessary because never used again but eh, I like consistency
                        state.tileCords[val[5]][2] = false      #Ensures that the tile isn't rendered
                        unless state.tileGrid[val[5]][0] == 0   #If tile is the left most tile in the row, right doesn't get rendered
                            state.tileGrid[val[5] - 1][4] = true            #Why the order value is amazing
                            state.tileCords[val[5] - 1][4] = true
                        end
                        unless state.tileGrid[val[5]][1] == state.quantity - 1     #Same but left side
                            state.tileGrid[val[5] + state.quantity][3] = true
                            state.tileCords[val[5] + state.quantity][3] = true
                        end
                    elsif state.mode == :insert
                        #adds the current sprite value selected to tileCords. (changes from the -1 earlier)
                        val[6] = rand(state.spriteSelection.length)
                    end
                end
            end
        end
    end

    def switchModes
        #Switches between insert and delete modes
        if inputs.keyboard.key_up.i && state.mode == :delete
            state.mode = :insert
            inputs.keyboard.clear
        elsif inputs.keyboard.key_up.d && state.mode == :insert
            state.mode = :delete
            inputs.keyboard.clear
        end
    end

end

$isometric = Isometric.new

def tick args
    $isometric.grid    = args.grid
    $isometric.inputs  = args.inputs
    $isometric.state   = args.state
    $isometric.outputs = args.outputs
    $isometric.tick
end

Genre Rpg Topdown link

Topdown Casino - main.rb link

# ./samples/99_genre_rpg_topdown/topdown_casino/app/main.rb
$gtk.reset

def coinflip
  rand < 0.5
end

class Game
  attr_accessor :args

  def text_font
    return nil #"rpg.ttf"
  end

  def text_color
    [ 255, 255, 255, 255 ]
  end

  def set_gem_values
    @args.state.gem0 = ((coinflip) ?  100 : 20)
    @args.state.gem1 = ((coinflip) ? -10 : -50)
    @args.state.gem2 = ((coinflip) ? -10 : -30)
    if coinflip
      tmp = @args.state.gem0
      @args.state.gem0 = @args.state.gem1
      @args.state.gem1 = tmp
    end
    if coinflip
      tmp = @args.state.gem1
      @args.state.gem1 = @args.state.gem2
      @args.state.gem2 = tmp
    end
    if coinflip
      tmp = @args.state.gem0
      @args.state.gem0 = @args.state.gem2
      @args.state.gem2 = tmp
    end
  end

  def initialize args
    @args = args
    @args.state.animticks = 0
    @args.state.score = 0
    @args.state.gem_chosen = false
    @args.state.round_finished = false
    @args.state.gem0_x = 197
    @args.state.gem0_y = 720-274
    @args.state.gem1_x = 623
    @args.state.gem1_y = 720-274
    @args.state.gem2_x = 1049
    @args.state.gem2_y = 720-274
    @args.state.hero_sprite = "sprites/herodown100.png"
    @args.state.hero_x = 608
    @args.state.hero_y = 720-656
    @args.state.hero.sprite ||= []
    set_gem_values
  end

  def render_gem_value x, y, gem
    if @args.state.gem_chosen
      @args.outputs.labels << [ x, y + 96, gem.to_s, 1, 1, *text_color, text_font ]
    end
  end

  def render
    gemsprite = ((@args.state.animticks % 400) < 200) ? 'sprites/gem200.png' : 'sprites/gem400.png'
    @args.outputs.background_color = [ 0, 0, 0, 255 ]
    @args.outputs.sprites << [608, 720-150, 64, 64, 'sprites/oldman.png']
    @args.outputs.sprites << [300, 720-150, 64, 64, 'sprites/fire.png']
    @args.outputs.sprites << [900, 720-150, 64, 64, 'sprites/fire.png']
    @args.outputs.sprites << [@args.state.gem0_x, @args.state.gem0_y, 32, 64, gemsprite]
    @args.outputs.sprites << [@args.state.gem1_x, @args.state.gem1_y, 32, 64, gemsprite]
    @args.outputs.sprites << [@args.state.gem2_x, @args.state.gem2_y, 32, 64, gemsprite]
    @args.outputs.sprites << [@args.state.hero_x, @args.state.hero_y, 64, 64, @args.state.hero_sprite]

    @args.outputs.labels << [ 630, 720-30, "IT'S A SECRET TO EVERYONE.", 1, 1, *text_color, text_font ]
    @args.outputs.labels << [ 50, 720-85, @args.state.score.to_s, 1, 1, *text_color, text_font ]
    render_gem_value @args.state.gem0_x, @args.state.gem0_y, @args.state.gem0
    render_gem_value @args.state.gem1_x, @args.state.gem1_y, @args.state.gem1
    render_gem_value @args.state.gem2_x, @args.state.gem2_y, @args.state.gem2
  end

  def calc
    @args.state.animticks += 16

    return unless @args.state.gem_chosen
    @args.state.round_finished_debounce ||= 60 * 3
    @args.state.round_finished_debounce -= 1
    return if @args.state.round_finished_debounce > 0

    @args.state.gem_chosen = false
    @args.state.hero.sprite[0] = 'sprites/herodown100.png'
    @args.state.hero.sprite[1] = 608
    @args.state.hero.sprite[2] = 656
    @args.state.round_finished_debounce = nil
    set_gem_values
  end

  def walk xdir, ydir, anim
    @args.state.hero_sprite = "sprites/#{anim}#{(((@args.state.animticks % 200) < 100) ? '100' : '200')}.png"
    @args.state.hero_x += 5 * xdir
    @args.state.hero_y += 5 * ydir
  end

  def check_gem_touching gem_x, gem_y, gem
    return if @args.state.gem_chosen
    herorect = [ @args.state.hero_x, @args.state.hero_y, 64, 64 ]
    return if !herorect.intersect_rect?([gem_x, gem_y, 32, 64])
    @args.state.gem_chosen = true
    @args.state.score += gem
    @args.outputs.sounds << ((gem < 0) ? 'sounds/lose.wav' : 'sounds/win.wav')
  end

  def input
    if @args.inputs.keyboard.key_held.left
      walk(-1.0, 0.0, 'heroleft')
    elsif @args.inputs.keyboard.key_held.right
      walk(1.0, 0.0, 'heroright')
    elsif @args.inputs.keyboard.key_held.up
      walk(0.0, 1.0, 'heroup')
    elsif @args.inputs.keyboard.key_held.down
      walk(0.0, -1.0, 'herodown')
    end

    check_gem_touching(@args.state.gem0_x, @args.state.gem0_y, @args.state.gem0)
    check_gem_touching(@args.state.gem1_x, @args.state.gem1_y, @args.state.gem1)
    check_gem_touching(@args.state.gem2_x, @args.state.gem2_y, @args.state.gem2)
  end

  def tick
    input
    calc
    render
  end
end

def tick args
    args.state.game ||= Game.new args
    args.state.game.args = args
    args.state.game.tick
end

Topdown Starting Point - main.rb link

# ./samples/99_genre_rpg_topdown/topdown_starting_point/app/main.rb
=begin
 APIs listing that haven't been encountered in previous sample apps:

 - reverse: Returns a new string with the characters from original string in reverse order.
   For example, the command "dragonruby".reverse would return the string "yburnogard".
   Reverse is not only limited to strings, but can be applied to arrays and other collections.

 Reminders:

 - HASH#intersect_rect?: Returns true or false depending on if two rectangles intersect.

 - args.outputs.labels: Added a hash to this collection will generate a label.
   The parameters are:
   {
     x: X,
     y: y,
     text: TEXT,
     size_px: 22 (optional),
     anchor_x: 0 (optional),
     anchor_y: 0 (optional),
     r: RED (optional),
     g: GREEN (optional),
     b: BLUE (optional),
     a: ALPHA (optional),
     font: PATH_TO_TTF (optional)
   }
=end

# This code shows a maze and uses input from the keyboard to move the user around the screen.
# The objective is to reach the goal.

# Sets values of tile size and player's movement speed
# Also creates tile or box for player and generates map
def tick args
  args.state.tile_size     = 80
  args.state.player_speed  = 4
  args.state.player      ||= tile(args, 7, 3, 0, 128, 180)
  generate_map args

  # Adds walls, goal, and player to args.outputs.solids so they appear on screen
  args.outputs.sprites << args.state.walls
  args.outputs.sprites << args.state.goal
  args.outputs.sprites << args.state.player

  # If player's box intersects with goal, a label is output onto the screen
  if args.state.player.intersect_rect? args.state.goal
    args.outputs.labels << { x: 30, y: 720 - 30, text: "You're a wizard Harry!!" } # 30 pixels lower than top of screen
  end

  move_player args, -1,  0 if args.inputs.keyboard.left # x position decreases by 1 if left key is pressed
  move_player args,  1,  0 if args.inputs.keyboard.right # x position increases by 1 if right key is pressed
  move_player args,  0,  1 if args.inputs.keyboard.up # y position increases by 1 if up is pressed
  move_player args,  0, -1 if args.inputs.keyboard.down # y position decreases by 1 if down is pressed
end

# Sets position, size, and color of the tile
def tile args, x, y, r, g, b
  {
    x: x * args.state.tile_size, # sets definition for array using method parameters
    y: y * args.state.tile_size, # multiplying by tile_size sets x and y to correct position using pixel values
    w: args.state.tile_size,
    h: args.state.tile_size,
    path: :pixel,
    r: r,
    g: g,
    b: b
  }
end

# Creates map by adding tiles to the wall, as well as a goal (that the player needs to reach)
def generate_map args
  return if args.state.area

  # Creates the area of the map. There are 9 rows running horizontally across the screen
  # and 16 columns running vertically on the screen. Any spot with a "1" is not
  # open for the player to move into (and is green), and any spot with a "0" is available
  # for the player to move in.
  args.state.area = [
    [1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1,],
    [1, 1, 1, 2, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1,], # the "2" represents the goal
    [1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1,],
    [1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1,],
    [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,],
    [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,],
    [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1,],
    [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,],
    [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 ],
  ].reverse # reverses the order of the area collection

  # By reversing the order, the way that the area appears above is how it appears
  # on the screen in the game. If we did not reverse, the map would appear inverted.

  #The wall starts off with no tiles.
  args.state.walls = []

  # If v is 1, a green tile is added to args.state.walls.
  # If v is 2, a black tile is created as the goal.
  args.state.area.map_2d do |y, x, v|
    if    v == 1
      args.state.walls << tile(args, x, y, 0, 255, 0) # green tile
    elsif v == 2 # notice there is only one "2" above because there is only one single goal
      args.state.goal   = tile(args, x, y, 0,   0, 0) # black tile
    end
  end
end

# Allows the player to move their box around the screen
def move_player args, vector_x, vector_y
  player = args.state.player
  next_x = player.x + vector_x * args.state.player_speed
  next_y = player.y + vector_y * args.state.player_speed
  next_position = args.state.player.merge x: next_x, y: next_y

  # If the player's box hits a wall, it is not able to move further in that direction
  return if next_x < 0 || (next_x + player.w) > 1280
  return if next_y < 0 || (next_y + player.h) > 720
  return if args.state.walls.any_intersect_rect? next_position

  # Player's box is able to move at angles (not just the four general directions) fast
  args.state.player.x = next_x
  args.state.player.y = next_y
end

Genre Rpg Turn Based link

Turn Based Battle - main.rb link

# ./samples/99_genre_rpg_turn_based/turn_based_battle/app/main.rb
def tick args
  args.state.phase ||= :selecting_top_level_action
  args.state.potential_action ||= :attack
  args.state.currently_acting_hero_index ||= 0
  args.state.enemies ||= [
    { name: "Goblin A" },
    { name: "Goblin B" },
    { name: "Goblin C" }
  ]

  args.state.heroes ||= [
    { name: "Hero A" },
    { name: "Hero B" },
    { name: "Hero C" }
  ]

  args.state.potential_enemy_index ||= 0

  if args.state.phase == :selecting_top_level_action
    if args.inputs.keyboard.key_down.down
      case args.state.potential_action
      when :attack
        args.state.potential_action = :special
      when :special
        args.state.potential_action = :magic
      when :magic
        args.state.potential_action = :items
      when :items
        args.state.potential_action = :items
      end
    elsif args.inputs.keyboard.key_down.up
      case args.state.potential_action
      when :attack
        args.state.potential_action = :attack
      when :special
        args.state.potential_action = :attack
      when :magic
        args.state.potential_action = :special
      when :items
        args.state.potential_action = :magic
      end
    end

    if args.inputs.keyboard.key_down.enter
      args.state.selected_action = args.state.potential_action
      args.state.next_phase = :selecting_target
    end
  end

  if args.state.phase == :selecting_target
    if args.inputs.keyboard.key_down.left
      select_previous_live_enemy args
    elsif args.inputs.keyboard.key_down.right
      select_next_live_enemy args
    end

    args.state.potential_enemy_index = args.state.potential_enemy_index.clamp(0, args.state.enemies.length - 1)

    if args.inputs.keyboard.key_down.enter
      args.state.enemies[args.state.potential_enemy_index].dead = true
      args.state.potential_enemy_index = args.state.enemies.find_index { |e| !e.dead }
      args.state.selected_action = nil
      args.state.potential_action = :attack
      args.state.next_phase = :selecting_top_level_action
      args.state.currently_acting_hero_index += 1
      if args.state.currently_acting_hero_index >= args.state.heroes.length
        args.state.currently_acting_hero_index = 0
      end
    end
  end

  if args.state.next_phase
    args.state.phase = args.state.next_phase
    args.state.next_phase = nil
  end

  render_actions_menu args
  render_enemies args
  render_heroes args
  render_hero_statuses args
end

def select_next_live_enemy args
  next_target_index = args.state.enemies.find_index.with_index { |e, i| !e.dead && i > args.state.potential_enemy_index }
  if next_target_index
    args.state.potential_enemy_index = next_target_index
  end
end

def select_previous_live_enemy args
  args.state.potential_enemy_index -= 1
  if args.state.potential_enemy_index < 0
    args.state.potential_enemy_index = 0
  elsif args.state.enemies[args.state.potential_enemy_index].dead
    select_previous_live_enemy args
  end
end

def render_actions_menu args
  args.outputs.borders << args.layout.rect(row:  8, col: 0, w: 4, h: 4, include_row_gutter: true, include_col_gutter: true)
  if !args.state.selected_action
    selected_rect = if args.state.potential_action == :attack
                      args.layout.rect(row:  8, col: 0, w: 4, h: 1)
                    elsif args.state.potential_action == :special
                      args.layout.rect(row:  9, col: 0, w: 4, h: 1)
                    elsif args.state.potential_action == :magic
                      args.layout.rect(row: 10, col: 0, w: 4, h: 1)
                    elsif args.state.potential_action == :items
                      args.layout.rect(row: 11, col: 0, w: 4, h: 1)
                    end

    args.outputs.solids  << selected_rect.merge(r: 200, g: 200, b: 200)
  end

  args.outputs.borders << args.layout.rect(row:  8, col: 0, w: 4, h: 1)
  args.outputs.labels  << args.layout.rect(row:  8, col: 0, w: 4, h: 1).center.merge(text: "Attack", vertical_alignment_enum: 1, alignment_enum: 1)

  args.outputs.borders << args.layout.rect(row:  9, col: 0, w: 4, h: 1)
  args.outputs.labels  << args.layout.rect(row:  9, col: 0, w: 4, h: 1).center.merge(text: "Special", vertical_alignment_enum: 1, alignment_enum: 1)

  args.outputs.borders << args.layout.rect(row: 10, col: 0, w: 4, h: 1)
  args.outputs.labels  << args.layout.rect(row: 10, col: 0, w: 4, h: 1).center.merge(text: "Magic", vertical_alignment_enum: 1, alignment_enum: 1)

  args.outputs.borders << args.layout.rect(row: 11, col: 0, w: 4, h: 1)
  args.outputs.labels  << args.layout.rect(row: 11, col: 0, w: 4, h: 1).center.merge(text: "Items", vertical_alignment_enum: 1, alignment_enum: 1)
end

def render_enemies args
  args.outputs.primitives << args.state.enemies.map_with_index do |e, i|
    if e.dead
      nil
    elsif i == args.state.potential_enemy_index && args.state.phase == :selecting_target
      [
        args.layout.rect(row: 1, col: 9 + i * 2, w: 2, h: 2).solid!(r: 200, g: 200, b: 200),
        args.layout.rect(row: 1, col: 9 + i * 2, w: 2, h: 2).border!,
        args.layout.rect(row: 1, col: 9 + i * 2, w: 2, h: 2).center.label!(text: "#{e.name}", vertical_alignment_enum: 1, alignment_enum: 1)
      ]
    else
      [
        args.layout.rect(row: 1, col: 9 + i * 2, w: 2, h: 2).border!,
        args.layout.rect(row: 1, col: 9 + i * 2, w: 2, h: 2).center.label!(text: "#{e.name}", vertical_alignment_enum: 1, alignment_enum: 1)
      ]
    end
  end
end

def render_heroes args
  args.outputs.primitives << args.state.heroes.map_with_index do |h, i|
    if i == args.state.currently_acting_hero_index
      [
        args.layout.rect(row: 5, col: 9 + i * 2, w: 2, h: 2).solid!(r: 200, g: 200, b: 200),
        args.layout.rect(row: 5, col: 9 + i * 2, w: 2, h: 2).border!,
        args.layout.rect(row: 5, col: 9 + i * 2, w: 2, h: 2).center.label!(text: "#{h.name}", vertical_alignment_enum: 1, alignment_enum: 1)
      ]
    else
      [
        args.layout.rect(row: 5, col: 9 + i * 2, w: 2, h: 2).border!,
        args.layout.rect(row: 5, col: 9 + i * 2, w: 2, h: 2).center.label!(text: "#{h.name}", vertical_alignment_enum: 1, alignment_enum: 1)
      ]
    end
  end
end

def render_hero_statuses args
  args.outputs.borders << args.layout.rect(row: 8, col: 4, w: 20, h: 4, include_col_gutter: true, include_row_gutter: true)
end

$gtk.reset

Genre Simulation link

Sand main.rb link

# ./samples/99_genre_simulation/sand_simulation/app/main.rb
class Elements
  def initialize size
    @size = size
    @max_x_ordinal = 1280.idiv size
    @element_lookup = {}
    @elements = []
  end

  def add_element x_ordinal, y_ordinal
    return nil if @element_lookup.dig x_ordinal, y_ordinal
    element = Element.new x_ordinal, y_ordinal, @size
    @elements << element
    rehash_elements
    element
  end

  def tick
    fn.each_send @elements, self, :move_element
    rehash_elements
  end

  def move_element element
    if below_empty?(element) && element.y_ordinal != 0
      element.move  0, -1
    elsif below_left_empty?(element) && element.y_ordinal != 0 && element.x_ordinal != 0
      element.move -1, -1
    elsif below_right_empty?(element) && element.y_ordinal != 0 && element.x_ordinal != @max_x_ordinal
      element.move  1, -1
    end
  end

  def element_count
    @elements.length
  end

  def rehash_elements
    @element_lookup.clear
    fn.each_send @elements, self, :rehash_element
  end

  def rehash_element element
    @element_lookup[element.x_ordinal] ||= {}
    @element_lookup[element.x_ordinal][element.y_ordinal] = element
  end

  def below_empty? e
    return false if e.y_ordinal == 0
    return true  if !@element_lookup[e.x_ordinal]
    return true  if !@element_lookup[e.x_ordinal][e.y_ordinal - 1]
    return false if  @element_lookup[e.x_ordinal][e.y_ordinal - 1]
    return true
  end

  def below_left_empty? e
    return false if e.y_ordinal == 0
    return false if e.x_ordinal == 0
    return true  if !@element_lookup[e.x_ordinal - 1]
    return true  if !@element_lookup[e.x_ordinal - 1][e.y_ordinal - 1]
    return false if  @element_lookup[e.x_ordinal - 1][e.y_ordinal - 1]
    return true
  end

  def below_right_empty? e
    return false if e.y_ordinal == 0
    return false if e.x_ordinal == 256
    return true  if !@element_lookup[e.x_ordinal + 1]
    return true  if !@element_lookup[e.x_ordinal + 1][e.y_ordinal - 1]
    return false if  @element_lookup[e.x_ordinal + 1][e.y_ordinal - 1]
    return true
  end
end

class Element
  attr_sprite
  attr :x_ordinal, :y_ordinal

  def initialize x_ordinal, y_ordinal, s
    @x_ordinal     = x_ordinal
    @y_ordinal     = y_ordinal
    @s             = s
    @x             = x_ordinal * s
    @y             = y_ordinal * s
    @w             = s
    @h             = s
    @path          = "sprites/sand-element.png"
  end

  def draw_override ffi
    ffi.draw_sprite @x, @y, @w, @h, @path
  end

  def move dx, dy
    @y_ordinal += dy
    @x_ordinal += dx
    @y = @y_ordinal * @s
    @x = @x_ordinal * @s
  end
end

def tick args
  args.state.size        ||= 10
  args.state.mouse_state ||= :up
  @elements              ||= Elements.new args.state.size

  if args.inputs.mouse.down
    args.state.mouse_state = :held
  elsif args.inputs.mouse.up
    args.state.mouse_state = :released
  end

  if args.state.mouse_state == :held
    added = @elements.add_element args.inputs.mouse.x.idiv(args.state.size), args.inputs.mouse.y.idiv(args.state.size)
    args.outputs.static_sprites << added if added
  end

  @elements.tick

  args.outputs.labels << { x: 30, y: 30.from_top, text: "#{args.gtk.current_framerate.to_sf}" }
  args.outputs.labels << { x: 30, y: 60.from_top, text: "#{@elements.element_count}" }
end

$gtk.reset
@elements = nil

Genre Twenty Second Games link

Twenty Second Starting Point - main.rb link

# ./samples/99_genre_twenty_second_games/twenty_second_starting_point/app/main.rb
# full documenation is at http://docs.dragonruby.org
# be sure to come to the discord if you hit any snags: http://discord.dragonruby.org
def tick args
  # ====================================================
  # initialize default variables
  # ====================================================

  # ruby has an operator called ||= which means "only initialize this if it's nil"
  args.state.count_down   ||= 20 * 60 # set the count down to 20 seconds
  # set the initial position of the target
  args.state.target       ||= { x: args.grid.w.half,
                                y: args.grid.h.half,
                                w: 20,
                                h: 20 }

  # set the initial position of the player
  args.state.player       ||= { x: 50,
                                y: 50,
                                w: 20,
                                h: 20 }

  # set the player movement speed
  args.state.player_speed ||= 5

  # set the score
  args.state.score        ||= 0
  args.state.teleports    ||= 3

  # set the instructions
  args.state.instructions ||= "Get to the red goal! Use arrow keys to move. Spacebar to teleport (use them carefully)!"

  # ====================================================
  # render the game
  # ====================================================
  args.outputs.labels  << { x: args.grid.w.half, y: args.grid.h - 10,
                            text: args.state.instructions,
                            alignment_enum: 1 }

  # check if it's game over. if so, then render game over
  # otherwise render the current time left
  if game_over? args
    args.outputs.labels  << { x: args.grid.w.half,
                              y: args.grid.h - 40,
                              text: "game over! (press r to start over)",
                              alignment_enum: 1 }
  else
    args.outputs.labels  << { x: args.grid.w.half,
                              y: args.grid.h - 40,
                              text: "time left: #{(args.state.count_down.idiv 60) + 1}",
                              alignment_enum: 1 }
  end

  # render the score
  args.outputs.labels  << { x: args.grid.w.half,
                            y: args.grid.h - 70,
                            text: "score: #{args.state.score}",
                            alignment_enum: 1 }

  # render the player with teleport count
  args.outputs.sprites << { x: args.state.player.x,
                            y: args.state.player.y,
                            w: args.state.player.w,
                            h: args.state.player.h,
                            path: 'sprites/square-green.png' }

  args.outputs.labels << { x: args.state.player.x + 10,
                           y: args.state.player.y + 40,
                           text: "teleports: #{args.state.teleports}",
                           alignment_enum: 1, size_enum: -2 }

  # render the target
  args.outputs.sprites << { x: args.state.target.x,
                            y: args.state.target.y,
                            w: args.state.target.w,
                            h: args.state.target.h,
                            path: 'sprites/square-red.png' }

  # ====================================================
  # run simulation
  # ====================================================

  # count down calculation
  args.state.count_down -= 1
  args.state.count_down = -1 if args.state.count_down < -1

  # ====================================================
  # process player input
  # ====================================================
  # if it isn't game over let them move
  if !game_over? args
    dir_y = 0
    dir_x = 0

    # determine the change horizontally
    if args.inputs.keyboard.up
      dir_y += args.state.player_speed
    elsif args.inputs.keyboard.down
      dir_y -= args.state.player_speed
    end

    # determine the change vertically
    if args.inputs.keyboard.left
      dir_x -= args.state.player_speed
    elsif args.inputs.keyboard.right
      dir_x += args.state.player_speed
    end

    # determine if teleport can be used
    if args.inputs.keyboard.key_down.space && args.state.teleports > 0
      args.state.teleports -= 1
      dir_x *= 20
      dir_y *= 20
    end

    # apply change to player
    args.state.player.x += dir_x
    args.state.player.y += dir_y
  else
    # if r is pressed, reset the game
    if args.inputs.keyboard.key_down.r
      $gtk.reset
      return
    end
  end

  # ====================================================
  # determine score
  # ====================================================

  # calculate new score if the player is at goal
  if !game_over? args

    # if the player is at the goal, then move the goal
    if args.state.player.intersect_rect? args.state.target
      # increment the goal
      args.state.score += 1

      # move the goal to a random location
      args.state.target = { x: (rand args.grid.w), y: (rand args.grid.h), w: 20, h: 20 }

      # make sure the goal is inside the view area
      if args.state.target.x < 0
        args.state.target.x += 20
      elsif args.state.target.x > 1280
        args.state.target.x -= 20
      end

      # make sure the goal is inside the view area
      if args.state.target.y < 0
        args.state.target.y += 20
      elsif args.state.target.y > 720
        args.state.target.y -= 20
      end
    end
  end
end

def game_over? args
  args.state.count_down < 0
end

$gtk.reset