Sketch for a game of pong in kyoto

pong.rb

require 'kyoto'

use 'actors/velocity'
use 'actors/bound_to_world'
use 'game/pausable'
use 'game/score'
use 'color'
use 'collision_detection'

class Paddle < Actor
	acts_as_bound_to_world
	width 50.px
	height 20.px
	def draw
		rect(bounds,:color => Color.white)
	end
end

class AIPaddle < Paddle
	def update
		# here be AI
	end
end

class Ball < Actor
	R = 5.px
	
	acts_as_bound_to_world :reflect => true
	
	def on_collision_with(o)
		if o.is_a?(Paddle)
			# reflect
		elsif o.is_a?(World)
			# score
			game.restart
		end
	end
	
	def draw
		circle(bounds.midpoint,R)
	end
end

class Pong < Game
	def setup
		@player = Paddle.new(Screen.center,Screen.bottom-Paddle.height)
		@ai = AIPaddle.new(Screen.center,Screen.top+Paddle.height)
		@ball = Ball.new(Screen.midpoint)
	end
	
	def restart
		@ball.bounds.midpoint = Screen.midpoint
		@ball.velocity.y = [-1,1].rand
		@ball.velocity.x = randomly_between(-2..2)
	end
end