diff --git a/vcg/space/index/kdtree/priorityqueue.h b/vcg/space/index/kdtree/priorityqueue.h
index 956dc54f..b5bf1c38 100755
--- a/vcg/space/index/kdtree/priorityqueue.h
+++ b/vcg/space/index/kdtree/priorityqueue.h
@@ -21,109 +21,142 @@
 *                                                                           *
 ****************************************************************************/
 
-#ifndef _PriorityQueue_h_
-#define _PriorityQueue_h_
+#ifndef _PRIORITYQUEUE_H_
+#define _PRIORITYQUEUE_H_
 
-/** Implements a bounded-size max priority queue using a heap
-*/
-template <typename Index, typename Weight>
-class HeapMaxPriorityQueue
-{
-	struct Element
+#include <algorithm>
+
+namespace vcg {
+
+	/** Implements a bounded-size max priority queue using a heap
+	*/
+	template <typename Index, typename Weight>
+	class HeapMaxPriorityQueue
 	{
+		struct Element
+		{
 			Weight weight;
 			Index index;
+		};
+
+
+		struct 
+		{
+			bool operator()(const Element& a, const Element& b) const
+			{   
+				return a.weight < b.weight;
+			}   
+		} lessElement;
+
+
+		struct 
+		{
+			bool operator()(const Element& a, const Element& b) const
+			{   
+				return a.weight > b.weight;
+			}   
+		} greaterElement;
+
+
+
+	public:
+
+		HeapMaxPriorityQueue(void)
+		{
+			mElements = 0;
+			mMaxSize = 0;
+		}
+
+		~HeapMaxPriorityQueue()
+		{
+			if (mElements)
+				delete[] mElements;
+		}
+
+
+		inline void setMaxSize(int maxSize)
+		{
+			if (mMaxSize!=maxSize)
+			{
+				mMaxSize = maxSize;
+				delete[] mElements;
+				mElements = new Element[mMaxSize];
+				mpOffsetedElements = (mElements-1);
+			}
+			init();
+		}
+
+		inline void init() { mCount = 0; }
+
+		inline bool isFull() const { return mCount == mMaxSize; }
+
+		/** returns number of elements inserted in queue
+		*/
+		inline int getNofElements() const { return mCount; }
+
+		inline Weight getWeight(int i) const { return mElements[i].weight; }
+		inline Index  getIndex(int i) const { return mElements[i].index; }
+
+		inline Weight getTopWeight() const { return mElements[0].weight; }
+
+		inline void insert(Index index, Weight weight)
+		{
+			if (mCount==mMaxSize)
+			{
+				if (weight<mElements[0].weight)
+				{
+					register int j, k;
+					j = 1;
+					k = 2;
+					while (k <= mMaxSize)
+					{
+						Element* z = &(mpOffsetedElements[k]);
+						if ((k < mMaxSize) && (z->weight < mpOffsetedElements[k+1].weight))
+							z = &(mpOffsetedElements[++k]);
+
+						if(weight >= z->weight)
+							break;
+						mpOffsetedElements[j] = *z;
+						j = k;
+						k = 2 * j;
+					}
+					mpOffsetedElements[j].weight = weight;
+					mpOffsetedElements[j].index = index;
+				}
+			}
+			else
+			{
+				int i, j;
+				i = ++mCount;
+				while (i >= 2)
+				{
+					j = i >> 1;
+					Element& y = mpOffsetedElements[j];
+					if(weight <= y.weight)
+						break;
+					mpOffsetedElements[i] = y;
+					i = j;
+				}
+				mpOffsetedElements[i].index = index;
+				mpOffsetedElements[i].weight = weight;
+			}
+		}
+
+		inline void sort(bool ascending = true)
+		{
+			if (ascending)
+				std::sort(mElements, mElements + mCount, lessElement);
+			else
+				std::sort(mElements, mElements + mCount, greaterElement);
+		}
+
+	protected:
+
+		int mCount;
+		int mMaxSize;
+		Element* mElements;
+		Element* mpOffsetedElements;
 	};
 
-public:
-
-	HeapMaxPriorityQueue(void)
-	{
-		mElements = 0;
-		mMaxSize = 0;
-	}
-
-	~HeapMaxPriorityQueue()
-	{
-		if (mElements)
-			delete[] mElements;
-	}
-	
-
-	inline void setMaxSize(int maxSize)
-	{
-		if (mMaxSize!=maxSize)
-		{
-			mMaxSize = maxSize;
-			delete[] mElements;
-			mElements = new Element[mMaxSize];
-			mpOffsetedElements = (mElements-1);
-		}
-		init();
-	}
-
-	inline void init() { mCount = 0; }
-
-	inline bool isFull() const { return mCount == mMaxSize; }
-
-	/** returns number of elements inserted in queue
-	*/
-	inline int getNofElements() const { return mCount; }
-
-	inline Weight getWeight(int i) const { return mElements[i].weight; }
-	inline Index  getIndex(int i) const { return mElements[i].index; }
-
-	inline Weight getTopWeight() const { return mElements[0].weight; }
-
-	inline void insert(Index index, Weight weight)
-	{
-		if (mCount==mMaxSize)
-		{
-			if (weight<mElements[0].weight)
-			{
-				register int j, k;
-				j = 1;
-				k = 2;
-				while (k <= mMaxSize)
-				{
-					Element* z = &(mpOffsetedElements[k]);
-					if ((k < mMaxSize) && (z->weight < mpOffsetedElements[k+1].weight))
-						z = &(mpOffsetedElements[++k]);
-
-					if(weight >= z->weight)
-						break;
-					mpOffsetedElements[j] = *z;
-					j = k;
-					k = 2 * j;
-				}
-				mpOffsetedElements[j].weight = weight;
-				mpOffsetedElements[j].index = index;
-			}
-		}
-		else
-		{
-			int i, j;
-			i = ++mCount;
-			while (i >= 2)
-			{
-				j = i >> 1;
-				Element& y = mpOffsetedElements[j];
-				if(weight <= y.weight)
-					break;
-				mpOffsetedElements[i] = y;
-				i = j;
-			}
-			mpOffsetedElements[i].index = index;
-			mpOffsetedElements[i].weight = weight;
-		}
-	}
-
-protected:
-
-	int mCount;
-	int mMaxSize;
-	Element* mElements;
-	Element* mpOffsetedElements;
-};
-
+}
 #endif