assimp/code/SGSpatialSort.h

/*
Open Asset Import Library (ASSIMP)
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*/

/** Small helper classes to optimise finding vertizes close to a given location
 */
#ifndef AI_D3DSSPATIALSORT_H_INC
#define AI_D3DSSPATIALSORT_H_INC

#include <vector>
#include "../include/aiTypes.h"

namespace Assimp	{

// ----------------------------------------------------------------------------------
/** Specialized version of SpatialSort to support smoothing groups
 *  This is used in by the 3DS, ASE and LWO loaders. 3DS and ASE share their 
 *  normal computation code in SmoothingGroups.inl, the LWO loader has its own
 *  implementation to handle all details of its file format correctly.
 */
// ----------------------------------------------------------------------------------
class SGSpatialSort
{
public:

	SGSpatialSort();

	// -------------------------------------------------------------------
	/** Construction from a given face array, handling smoothing groups
	 *  properly
	 */
	SGSpatialSort(const std::vector<aiVector3D>& vPositions);

	// -------------------------------------------------------------------
	/** Add a vertex to the spatial sort
	 * @param vPosition Vertex position to be added
	 * @param index Index of the vrtex
	 * @param smoothingGroup SmoothingGroup for this vertex
	 */
	void Add(const aiVector3D& vPosition, unsigned int index,
		unsigned int smoothingGroup);

	// -------------------------------------------------------------------
	/** Prepare the spatial sorter for use. This step runs in O(logn)
	 */
	void Prepare();

	/** Destructor */
	~SGSpatialSort();

	// -------------------------------------------------------------------
	/** Returns an iterator for all positions close to the given position.
	 * @param pPosition The position to look for vertices.
	 * @param pSG Only included vertices with at least one shared smooth group
	 * @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.
	 * @param exactMatch Specifies whether smoothing groups are bit masks 
	 *   (false) or integral values (true). In the latter case, a vertex
	 *   cannot belong to more than one smoothing group.
	 * @return An iterator to iterate over all vertices in the given area.
	 */
	// -------------------------------------------------------------------
	void FindPositions( const aiVector3D& pPosition, uint32_t pSG,
		float pRadius, std::vector<unsigned int>& poResults, 
		bool exactMatch = false) 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
		uint32_t mSmoothGroups;
		float mDistance;		///< Distance of this vertex to the sorting plane

		Entry() { /** intentionally not initialized.*/ }
		Entry( unsigned int pIndex, const aiVector3D& pPosition, float pDistance,uint32_t pSG) 
			: 
			mIndex( pIndex),
			mPosition( pPosition),
			mSmoothGroups (pSG),
			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