Initiual commit: AssetImporter source moved from ZFXCE repository to its own repository. PLease do not use the ZFXCE repo any more.

git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@1 67173fc5-114c-0410-ac8e-9d2fd5bffc1f

code/SpatialSort.h

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+/** Small helper classes to optimise finding vertizes close to a given location */
+#ifndef AI_SPATIALSORT_H_INC
+#define AI_SPATIALSORT_H_INC
+
+#include <vector>
+#include "../include/aiVector3D.h"
+
+namespace Assimp
+{
+
+// ------------------------------------------------------------------------------------------------
+/** A little helper class to quickly find all vertices in the epsilon environment of a given
+ * position. Construct an instance with an array of positions. The class stores the given positions
+ * by their indices and sorts them by their distance to an arbitrary chosen plane.
+ * You can then query the instance for all vertices close to a given position in an average O(log n) 
+ * time, with O(n) worst case complexity when all vertices lay on the plane. The plane is chosen
+ * so that it avoids common planes in usual data sets.
+ */
+class SpatialSort
+{
+public:
+
+	SpatialSort() {/* This is unintialized. This is evil. This is OK. */}
+
+	/** Constructs a spatially sorted representation from the given position array.
+	 * Supply the positions in its layout in memory, the class will only refer to them
+	 * by index.
+	 * @param pPositions Pointer to the first position vector of the array.
+	 * @param pNumPositions Number of vectors to expect in that array.
+	 * @param pElementOffset Offset in bytes from the beginning of one vector in memory to the beginning of the next vector.
+	 */
+	SpatialSort( const aiVector3D* pPositions, unsigned int pNumPositions, unsigned int pElementOffset);
+
+	/** Destructor */
+	~SpatialSort();
+
+	/** Returns an iterator for all positions close to the given position.
+	 * @param pPosition The position to look for vertices.
+	 * @param pRadius Maximal distance from the position a vertex may have to be counted in.
+	 * @param poResults The container to store the indices of the found positions. Will be emptied
+	 *   by the call so it may contain anything.
+	 * @return An iterator to iterate over all vertices in the given area.
+	 */
+	void FindPositions( const aiVector3D& pPosition, float pRadius, std::vector<unsigned int>& poResults) const;
+
+protected:
+	/** Normal of the sorting plane, normalized. The center is always at (0, 0, 0) */
+	aiVector3D mPlaneNormal;
+
+	/** An entry in a spatially sorted position array. Consists of a vertex index,
+	 * its position and its precalculated distance from the reference plane */
+	struct Entry
+	{
+		unsigned int mIndex; ///< The vertex referred by this entry
+		aiVector3D mPosition; ///< Position
+		float mDistance; ///< Distance of this vertex to the sorting plane
+
+		Entry() { /** intentionally not initialized.*/ }
+		Entry( unsigned int pIndex, const aiVector3D& pPosition, float pDistance) 
+			: mPosition( pPosition), mIndex( pIndex), mDistance( pDistance)
+		{ 	}
+
+		bool operator < (const Entry& e) const { return mDistance < e.mDistance; }
+	};
+
+	// all positions, sorted by distance to the sorting plane
+	std::vector<Entry> mPositions;
+};
+
+} // end of namespace Assimp
+
+#endif // AI_SPATIALSORT_H_INC