Added Phaser.Filter and started moving the shaders over into their own filter classes, so they won't all get bundled in unless needed.

src/gameobjects/GameObjectFactory.js

@@ -288,6 +288,26 @@ Phaser.GameObjectFactory.prototype = {
 
         return new Phaser.BitmapData(this.game, width, height);
 
+    },
+
+    /**
+    * A WebGL shader/filter that can be applied to Sprites.
+    *
+    * @method Phaser.GameObjectFactory#filter
+    * @param {string} filter - The name of the filter you wish to create, for example "HueRotate" or "SineWave"
+    * @param {...} - Whatever parameters are needed to be passed to the filter init function.
+    * @return {Phaser.Filter} The newly created Phaser.Filter object.
+    */
+    filter: function (filter) {
+
+        var args = Array.prototype.splice.call(arguments, 1);
+
+        var f = new Phaser.Filter[filter](this.game);
+
+        f.init.apply(f, args);
+
+        return f;
+
     }
 
 };

src/gameobjects/Sprite.js

@@ -118,11 +118,16 @@ Phaser.Sprite = function (game, x, y, key, frame) {
     }
     else
     {
-        if (key == null || this.game.cache.checkImageKey(key) == false)
+        if (key === null || typeof key === 'undefined')
         {
             key = '__default';
             this.key = key;
         }
+        else if (typeof key === 'string' && this.game.cache.checkImageKey(key) == false)
+        {
+            key = '__missing';
+            this.key = key;
+        }
 
         PIXI.Sprite.call(this, PIXI.TextureCache[key]);