gistfile1.coffee

window.Kata ?= {}
window.Kata.Particle = class Particle

  constructor: (@context, @vector, @position) ->
    @vector =
      x: Math.random() * 4 - 2
      y: Math.random() * 4 - 2
    @position =
      x: @context.canvas.width/2
      y: @context.canvas.height/2

  update: ->
    @position.x += @vector.x
    @position.y += @vector.y

    # update vectors
    if @position.x > @context.canvas.width - 10 or @position.x < 0
      @vector.x *= -1

    if @position.y > @context.canvas.height - 10 or @position.y < 0
      @vector.y *= -1

  draw: ->
    @context.fillStyle = '#00ffff'
    @context.fillRect @position.x, @position.y, 10, 10