Add worldAngleToPointer

Author: mattrick

src/physics/arcade/World.js

@@ -1698,4 +1698,21 @@ Phaser.Physics.Arcade.prototype = {
 
     }
 
+    /**
+    * Find the angle in radians between a display object (like a Sprite) and a Pointer, taking their x/y and center into account relative to the world.
+    *
+    * @method Phaser.Physics.Arcade#worldAngleToPointer
+    * @param {any} displayObject - The DisplayObjerct to test from.
+    * @param {Phaser.Pointer} [pointer] - The Phaser.Pointer to test to. If none is given then Input.activePointer is used.
+    * @return {number} The angle in radians between displayObject.x/y to Pointer.x/y
+    */
+     worldAngleToPointer: function (displayObject, pointer) {
+        pointer = pointer || game.input.activePointer;
+
+        var dx = pointer.worldX - displayObject.world.x;
+        var dy = pointer.worldY - displayObject.world.y;
+
+        return Math.atan2(dy, dx);
+    }
+
 };