Sorted out the bounds for when sprites are in trimmed texture atlases to stop the physics checks going insane. Also bundled in Advanced Physics lib, although not hooked up yet.

src/geom/Rectangle.js

@@ -11,10 +11,10 @@
 **/
 Phaser.Rectangle = function (x, y, width, height) {
 
-    if (typeof x === "undefined") { x = 0; }
-    if (typeof y === "undefined") { y = 0; }
-    if (typeof width === "undefined") { width = 0; }
-    if (typeof height === "undefined") { height = 0; }
+    x = x || 0;
+    y = y || 0;
+    width = width || 0;
+    height = height || 0;
 
     /**
      * @property x
@@ -449,6 +449,52 @@ Object.defineProperty(Phaser.Rectangle.prototype, "perimeter", {
     configurable: true
 });
 
+Object.defineProperty(Phaser.Rectangle.prototype, "centerX", {
+    
+    /**
+    * The x coordinate of the center of the Rectangle.
+    * @method centerX
+    * @return {Number}
+    **/
+    get: function () {
+        return this.x + this.halfWidth;
+    },
+
+    /**
+    * The x coordinate of the center of the Rectangle.
+    * @method centerX
+    * @param {Number} value
+    **/
+    set: function (value) {
+        this.x = value - this.halfWidth;
+    },
+    enumerable: true,
+    configurable: true
+});
+
+Object.defineProperty(Phaser.Rectangle.prototype, "centerY", {
+    
+    /**
+    * The y coordinate of the center of the Rectangle.
+    * @method centerY
+    * @return {Number}
+    **/
+    get: function () {
+        return this.y + this.halfHeight;
+    },
+
+    /**
+    * The y coordinate of the center of the Rectangle.
+    * @method centerY
+    * @param {Number} value
+    **/
+    set: function (value) {
+        this.y = value - this.halfHeight;
+    },
+    enumerable: true,
+    configurable: true
+});
+
 Object.defineProperty(Phaser.Rectangle.prototype, "top", {
     
     /**