amirrajan

ramp-collision.mp4

class Game
  attr :args

  def defaults
    args.state.terrain ||= [
      { x: 0,  y: 0, w: 128, h: 128, left_perc: 0, right_perc: 0.5 },
      { x: 128,  y: 64, w: 128, h: 128, left_perc: 0, right_perc: 1.0 },

amirrajan

def tick_intro args
  [
    Layout.rect(row: 0, col: 12)
          .merge(text: "DragonRuby Game Toolkit: Lessons Learned",
                 alignment_enum: 1,
                 vertical_alignment_enum: 1,
                 size_enum: 10, **white),
    Layout.rect(row: 1,   col: 12)
          .merge(text: "Amir Rajan", **centered_white_label),
    Layout.rect(row: 1.6, col: 12)

amirrajan

class Game
  attr :args

  def defaults
    args.state.terrain ||= [
      { x: 0,  y: 0, w: 128, h: 128, left_perc: 0, right_perc: 0.5 },
      { x: 128,  y: 64, w: 128, h: 128, left_perc: 0, right_perc: 1.0 },
      { x: 256,  y: 64, w: 128, h: 128, left_perc: 0.5, right_perc: 0 },
      { x: 384,  y: 64, w: 128, h: 128, left_perc: 0, right_perc: 0 },
    ]

amirrajan

class Game
  attr_gtk

  def tick
    defaults
    input
    calc
    render
  end

amirrajan

class Game
  attr_gtk

  def initialize
  end

  def defaults
    state.objects ||= []
  end

amirrajan

Things to consider when building a cross-platform game:

1. Minimum button sizes for touch displays and small screen (eg steamdeck, mobile, nintendo switch hand held mode) is about 60 pixels. Anything smaller will fail lotcheck (Apple, Android, Nintendo).
2. Visual feedback of UI interactions (Android, Apple -> they'll reject a feature/showcase of your game if you don't have this).
3. Safe area/layout considerations. Avoid things like notches and app switch "chin". If you're making a game that can render edge to edge/without letter boxing, test at an aspect ratio of 21:12 (1680x960). Your safe are should be centered with an aspect ratio of 16:9 (placement of UI controls should always be in the safe area or they may be inaccesible because of notches and beveled edges).
4. Button input detection with keyboard, touch, and gamepad. Navigation using keyboard, gamepad, mouse.
5. Anything below 22px font size is pretty much unreadable on small screens (mobile, Steam Deck, Switch Lite).
6. Text fields is a world of p

amirrajan

class Player
  def initialize
    @action_lookup = {
      idle: {
        frame_count: 7,
        dir: "sprites/player/idle",
        repeat: true
      },
      attack: {
        frame_count: 6,

amirrajan

def tick args
  # initialize state
  args.state.rects ||= []
  args.state.rect_size ||= 8
  args.state.move_squares ||= :no
  if args.inputs.keyboard.key_down.tab
    args.state.move_squares = args.state.move_squares == :yes ? :no : :yes
  end

  args.outputs.watch "FPS: #{GTK.current_framerate.to_sf}"

amirrajan

Here is a minimal setup that works on Windows and Mac (yes I use Emacs on Windows and it works well).

;; using an editor you are comfortable with
;; create c:/Users/USERNAME/AppData/Roaming/.emacs.d/init.el
;; and paste these contents in there:

;; NOTE: depending on how you start up emacs, your home directory may
;;       be different than the one above. Your initialization file 
;;       needs to be saved at ~/.emacs.d/init.el (however that is mapped

amirrajan

class Player
  attr :x, :y, :w, :h, :action, :action_at,
       :dx, :dy, :breathe_at, :facing, :run_speed, :on_ground_y, :on_ground,
       :prev_on_ground

  def initialize
    @breathe_at = -100
    @action = :idle
    @action_at = 0
    @x = 100