gistfile1.rb

require 'ray'

class BackgroundScene < Ray::Scene
  def setup
    @bg_color = Ray::Color.yellow
  end

  def render(win)
    win.clear @bg_color
  end
end

class ForegroundScene < Ray::Scene
  def setup(previous_scene)
    @previous_scene = previous_scene
    @figure = Ray::Polygon.rectangle([125, 125, 50, 50], Ray::Color.blue)
  end

  def render(win)
    @previous_scene.render(win)
    win.draw @figure
  end
end

class FoliationExample < Ray::Game
  def initialize
    super("Foliation example", :size => [300, 300])

    BackgroundScene.bind self
    ForegroundScene.bind self

    scene = registered_scene(:background_scene)
    scene.setup

    push_scene :foreground_scene, scene
  end
end

FoliationExample.new.run