Merge pull request #324 from Cocos2DXNA/SPRITE_BATCH_QSORT

changed sort to use qsort per advice from Ricardo.

Author: totallyeviljake

cocos2d/sprite_nodes/CCSpriteBatchNode.cs

@@ -214,16 +214,67 @@ public override void RemoveAllChildrenWithCleanup(bool cleanup)
             m_pobTextureAtlas.RemoveAllQuads();
         }
 
+        // Quick sort taken from http://snipd.net/quicksort-in-c
+        public static void Quicksort(CCNode[] elements, int left, int right)
+        {
+            int i = left, j = right;
+            CCNode pivot = elements[(left + right) / 2];
+
+            while (i <= j)
+            {
+                /*
+                           (pivot.m_nZOrder < elements[i].m_nZOrder ||
+                            (pivot.m_nZOrder == elements[i].m_nZOrder && pivot.m_uOrderOfArrival < elements[i].m_uOrderOfArrival)))
+                 */
+                while ((elements[i].m_nZOrder < pivot.m_nZOrder ||
+                            (pivot.m_nZOrder == elements[i].m_nZOrder && elements[i].m_uOrderOfArrival < pivot.m_uOrderOfArrival)))
+                {
+                    i++;
+                }
+
+                while ((elements[j].m_nZOrder > pivot.m_nZOrder ||
+                            (pivot.m_nZOrder == elements[j].m_nZOrder && elements[j].m_uOrderOfArrival > pivot.m_uOrderOfArrival)))
+                {
+                    j--;
+                }
+
+                if (i <= j)
+                {
+                    // Swap
+                    CCNode tmp = elements[i];
+                    elements[i] = elements[j];
+                    elements[j] = tmp;
+
+                    i++;
+                    j--;
+                }
+            }
+
+            // Recursive calls
+            if (left < j)
+            {
+                Quicksort(elements, left, j);
+            }
+
+            if (i < right)
+            {
+                Quicksort(elements, i, right);
+            }
+        }
+
         //override sortAllChildren
         public override void SortAllChildren()
         {
             if (m_bReorderChildDirty)
             {
                 int j = 0, count = m_pChildren.count;
                 CCNode[] elements = m_pChildren.Elements;
-                CCNode tempItem;
+                // CCNode tempItem;
+                
+                //insertion sort - change to qsort per RIQ
+                Quicksort(elements, 0, count - 1);
 
-                //insertion sort
+                /*
                 for (int i = 1; i < count; i++)
                 {
                     tempItem = elements[i];
@@ -240,6 +291,7 @@ public override void SortAllChildren()
 
                     elements[j + 1] = tempItem;
                 }
+                */
 
                 //sorted now check all children
                 if (count > 0)