#!ruby

class TestSprite < Sprite
  def initialize(x, y, imagefile, dx, dy)
    super(x, y, imagefile)
    @bx = x
    @by = y
    @dx = dx
    @dy = dy
  end

  def update
    wh = width / 2
    hh = height / 2
    @bx += @dx
    @by += @dy
    @dx *= -1 if (@bx <= wh or @bx >= 640 - wh)
    @dy *= -1 if (@by <= hh or @by >= 480 - hh)
    @x = (@bx - wh).to_i
    @y = (@by - hh).to_i
  end
end

class Scene
  def initialize
    @sprs = []
    num = 128
    ang = 0
    ang_d = 360.0 / num
    num.times do
      rad = ang * Math::PI / 180.0
      r = rand * 4.0 + 1.0
      dx = r * Math.cos(rad)
      dy = r * Math.sin(rad)
      s = TestSprite.new(320, 240, "sample.png", dx, dy)
      @sprs.push(s)
      ang += ang_d
    end
  end

  def update
    @sprs.each { |s| s.update }
  end

  def draw
    @sprs.each { |s| s.draw }
  end
end

Scene.new