Refactoring drawing of sprites

lib/scene.coffee

@@ -2,6 +2,13 @@ module.exports = class Scene
   constructor: (@screen, @context) ->
     @sprites = []
 
+  addSprite: (sprite) ->
+    @sprites.push sprite
+
+  redraw: ->
+    @screen.clear()
+    sprite.draw @context for sprite in @sprites
+
   draw: (image, x, y) ->
     @context.drawImage image, x, y
 

lib/sprite.coffee

@@ -8,6 +8,14 @@ module.exports = class Sprite
     else
       @initSprite(image)
 
+  setPosition: (x,y) ->
+    @x = x
+    @y = y
+
+  move: (x,y) ->
+    @x = @x + x
+    @y = @y + y
+
   initSprite: (image) ->
     @img = document.createElement 'canvas'
     @img.width = @width
@@ -16,9 +24,9 @@ module.exports = class Sprite
     ctx.drawImage image, @offset_x, @offset_y, @width, @height, 0, 0, @width, @height
     @drawCallback?()
 
-  draw: (scene, x, y) ->
+  draw: (context) ->
     if @image_complete
-      scene.draw @img, x, y
+      context.drawImage @img, @x, @y
     else
       @drawCallback = =>
-        scene.draw @img, x, y
+        context.drawImage @img, @x, @y

test/test.coffee

@@ -8,9 +8,12 @@ img = new Image
 img.src = '/images/simple_sprite.png'
 window.sprite = new Squash.Sprite img, 0, 0, 20, 20
 
-@x = 90
+@x = 0
 @y = 90
-sprite.draw scene, @x, @y
+
+sprite.setPosition(@x, @y)
+scene.addSprite sprite
+scene.redraw()
 
 window.timer = new Squash.Timer
 
@@ -21,10 +24,9 @@ timer.registerCallback (timeSinceLastTick) =>
     console.log "FPS: #{@ticks}"
     @ms = 0
     @ticks = 0
-    scene.clear()
-    @x = @x + 10
-    sprite.draw scene, @x, @y
+    sprite.move 10, 0
   else
     @ms += timeSinceLastTick
     @ticks += 1
+  scene.redraw()
 timer.start()