From 9d84429960b62a258fcc0171b52531994ae86e79 Mon Sep 17 00:00:00 2001
From: Richard Davey <rdavey@gmail.com>
Date: Tue, 24 Sep 2013 15:49:21 +0100
Subject: [PATCH] Group length checks

---
 src/physics/arcade/ArcadePhysics.js | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/physics/arcade/ArcadePhysics.js b/src/physics/arcade/ArcadePhysics.js
index 7db7a380..ca9d548f 100644
--- a/src/physics/arcade/ArcadePhysics.js
+++ b/src/physics/arcade/ArcadePhysics.js
@@ -268,6 +268,11 @@ Phaser.Physics.Arcade.prototype = {
 
     collideGroupVsTilemap: function (group, tilemap, collideCallback, processCallback, callbackContext) {
 
+        if (group.length == 0)
+        {
+            return;
+        }
+
         if (group._container.first._iNext)
         {
             var currentNode = group._container.first._iNext;
@@ -322,6 +327,11 @@ Phaser.Physics.Arcade.prototype = {
 
     collideSpriteVsGroup: function (sprite, group, collideCallback, processCallback, callbackContext) {
 
+        if (group.length == 0)
+        {
+            return;
+        }
+
         //  What is the sprite colliding with in the quadtree?
         this._potentials = this.quadTree.retrieve(sprite);
 
@@ -353,6 +363,11 @@ Phaser.Physics.Arcade.prototype = {
 
     collideGroupVsGroup: function (group1, group2, collideCallback, processCallback, callbackContext) {
 
+        if (group1.length == 0 || group2.length == 0)
+        {
+            return;
+        }
+
         if (group1._container.first._iNext)
         {
             var currentNode = group1._container.first._iNext;