require 'gosu'

class Window < Gosu::Window
  def initialize
    super 640, 480, false
    self.caption = 'Hello world!'
    @background_image = Gosu::Image.new(self, 'background.png', true)
    @bgmusic = Gosu::Song.new(self, 'song.ogg')
    @bgmusic.play true
  end

  def draw
    @background_image.draw(0, 0, 0)
  end
end

window = Window.new
window.show