bouncy circle

main.rb

class Game
  attr_gtk

  def tick
    fiddle
    defaults
    render
    input
    calc
  end

  def render
    outputs.solids << [0, 0, 1280, 100]
    outputs.sprites << circle_sprite
    outputs.lines << args.state.terrain
    if args.state.working_terrain_1
      if args.keyboard.shift?
        outputs.lines << [args.state.working_terrain_1,
                          inputs.mouse.x,
                          state.working_terrain_1.y]
      else
        outputs.lines << [args.state.working_terrain_1,
                          inputs.mouse.x,
                          inputs.mouse.y]
      end
    end
  end

  def input
    if inputs.mouse.press?
      if !state.working_terrain_1
        state.working_terrain_1 = [inputs.mouse.x, inputs.mouse.y]
      else
        if inputs.keyboard.shift?
          state.terrain << [state.working_terrain_1.x,
                            state.working_terrain_1.y,
                            inputs.mouse.x,
                            state.working_terrain_1.y]
        else
          state.terrain << [state.working_terrain_1.x,
                            state.working_terrain_1.y,
                            inputs.mouse.x,
                            inputs.mouse.y]
        end
        state.working_terrain_1 = nil
      end
    end
  end

  def circle_sprite
    [state.x, state.y, 50, 50, 'sprites/circle-green.png']
  end

  def fiddle
    state.gravity    = -0.5
    state.elasticity = 0.8
    state.entropy    = 0.8
  end

  def defaults
    state.x        ||= 640
    state.y        ||= 700
    state.dy       ||= state.gravity
    state.drag     ||= 0.005
    state.terrain  ||= []
  end

  def calc
    outputs.debug << [30, 690, state.dy].label

    if state.dy > 0 && state.dy < state.entropy
      state.dy = 0
    end

    state.y  += state.dy

    if state.y <= 100
      state.y = 100
      state.dy = (state.dy * -1) * state.elasticity
    else
      state.dy += state.gravity
      state.dy += (state.dy * state.drag) ** 2
    end
  end
end

$game = Game.new

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

$gtk.reset