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File indexing completed on 2025-02-21 09:30:10
0001 /* 0002 Open Asset Import Library (assimp) 0003 ---------------------------------------------------------------------- 0004 0005 Copyright (c) 2006-2024, assimp team 0006 0007 0008 All rights reserved. 0009 0010 Redistribution and use of this software in source and binary forms, 0011 with or without modification, are permitted provided that the 0012 following conditions are met: 0013 0014 * Redistributions of source code must retain the above 0015 copyright notice, this list of conditions and the 0016 following disclaimer. 0017 0018 * Redistributions in binary form must reproduce the above 0019 copyright notice, this list of conditions and the 0020 following disclaimer in the documentation and/or other 0021 materials provided with the distribution. 0022 0023 * Neither the name of the assimp team, nor the names of its 0024 contributors may be used to endorse or promote products 0025 derived from this software without specific prior 0026 written permission of the assimp team. 0027 0028 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 0029 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 0030 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 0031 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 0032 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 0033 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 0034 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 0035 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 0036 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 0037 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 0038 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 0039 0040 ---------------------------------------------------------------------- 0041 */ 0042 0043 /** Small helper classes to optimise finding vertizes close to a given location */ 0044 #pragma once 0045 #ifndef AI_SPATIALSORT_H_INC 0046 #define AI_SPATIALSORT_H_INC 0047 0048 #ifdef __GNUC__ 0049 #pragma GCC system_header 0050 #endif 0051 0052 #include <assimp/types.h> 0053 #include <vector> 0054 #include <limits> 0055 0056 namespace Assimp { 0057 0058 // ------------------------------------------------------------------------------------------------ 0059 /** A little helper class to quickly find all vertices in the epsilon environment of a given 0060 * position. Construct an instance with an array of positions. The class stores the given positions 0061 * by their indices and sorts them by their distance to an arbitrary chosen plane. 0062 * You can then query the instance for all vertices close to a given position in an average O(log n) 0063 * time, with O(n) worst case complexity when all vertices lay on the plane. The plane is chosen 0064 * so that it avoids common planes in usual data sets. */ 0065 // ------------------------------------------------------------------------------------------------ 0066 class ASSIMP_API SpatialSort { 0067 public: 0068 SpatialSort(); 0069 0070 // ------------------------------------------------------------------------------------ 0071 /** Constructs a spatially sorted representation from the given position array. 0072 * Supply the positions in its layout in memory, the class will only refer to them 0073 * by index. 0074 * @param pPositions Pointer to the first position vector of the array. 0075 * @param pNumPositions Number of vectors to expect in that array. 0076 * @param pElementOffset Offset in bytes from the beginning of one vector in memory 0077 * to the beginning of the next vector. */ 0078 SpatialSort(const aiVector3D *pPositions, unsigned int pNumPositions, 0079 unsigned int pElementOffset); 0080 0081 /** Destructor */ 0082 ~SpatialSort() = default; 0083 0084 // ------------------------------------------------------------------------------------ 0085 /** Sets the input data for the SpatialSort. This replaces existing data, if any. 0086 * The new data receives new indices in ascending order. 0087 * 0088 * @param pPositions Pointer to the first position vector of the array. 0089 * @param pNumPositions Number of vectors to expect in that array. 0090 * @param pElementOffset Offset in bytes from the beginning of one vector in memory 0091 * to the beginning of the next vector. 0092 * @param pFinalize Specifies whether the SpatialSort's internal representation 0093 * is finalized after the new data has been added. Finalization is 0094 * required in order to use #FindPosition() or #GenerateMappingTable(). 0095 * If you don't finalize yet, you can use #Append() to add data from 0096 * other sources.*/ 0097 void Fill(const aiVector3D *pPositions, unsigned int pNumPositions, 0098 unsigned int pElementOffset, 0099 bool pFinalize = true); 0100 0101 // ------------------------------------------------------------------------------------ 0102 /** Same as #Fill(), except the method appends to existing data in the #SpatialSort. */ 0103 void Append(const aiVector3D *pPositions, unsigned int pNumPositions, 0104 unsigned int pElementOffset, 0105 bool pFinalize = true); 0106 0107 // ------------------------------------------------------------------------------------ 0108 /** Finalize the spatial hash data structure. This can be useful after 0109 * multiple calls to #Append() with the pFinalize parameter set to false. 0110 * This is finally required before one of #FindPositions() and #GenerateMappingTable() 0111 * can be called to query the spatial sort.*/ 0112 void Finalize(); 0113 0114 // ------------------------------------------------------------------------------------ 0115 /** Returns an iterator for all positions close to the given position. 0116 * @param pPosition The position to look for vertices. 0117 * @param pRadius Maximal distance from the position a vertex may have to be counted in. 0118 * @param poResults The container to store the indices of the found positions. 0119 * Will be emptied by the call so it may contain anything. 0120 * @return An iterator to iterate over all vertices in the given area.*/ 0121 void FindPositions(const aiVector3D &pPosition, ai_real pRadius, 0122 std::vector<unsigned int> &poResults) const; 0123 0124 // ------------------------------------------------------------------------------------ 0125 /** Fills an array with indices of all positions identical to the given position. In 0126 * opposite to FindPositions(), not an epsilon is used but a (very low) tolerance of 0127 * four floating-point units. 0128 * @param pPosition The position to look for vertices. 0129 * @param poResults The container to store the indices of the found positions. 0130 * Will be emptied by the call so it may contain anything.*/ 0131 void FindIdenticalPositions(const aiVector3D &pPosition, 0132 std::vector<unsigned int> &poResults) const; 0133 0134 // ------------------------------------------------------------------------------------ 0135 /** Compute a table that maps each vertex ID referring to a spatially close 0136 * enough position to the same output ID. Output IDs are assigned in ascending order 0137 * from 0...n. 0138 * @param fill Will be filled with numPositions entries. 0139 * @param pRadius Maximal distance from the position a vertex may have to 0140 * be counted in. 0141 * @return Number of unique vertices (n). */ 0142 unsigned int GenerateMappingTable(std::vector<unsigned int> &fill, 0143 ai_real pRadius) const; 0144 0145 protected: 0146 /** Return the distance to the sorting plane. */ 0147 ai_real CalculateDistance(const aiVector3D &pPosition) const; 0148 0149 protected: 0150 /** Normal of the sorting plane, normalized. 0151 */ 0152 aiVector3D mPlaneNormal; 0153 0154 /** The centroid of the positions, which is used as a point on the sorting plane 0155 * when calculating distance. This value is calculated in Finalize. 0156 */ 0157 aiVector3D mCentroid; 0158 0159 /** An entry in a spatially sorted position array. Consists of a vertex index, 0160 * its position and its pre-calculated distance from the reference plane */ 0161 struct Entry { 0162 unsigned int mIndex; ///< The vertex referred by this entry 0163 aiVector3D mPosition; ///< Position 0164 /// Distance of this vertex to the sorting plane. This is set by Finalize. 0165 ai_real mDistance; 0166 0167 Entry() AI_NO_EXCEPT 0168 : mIndex(std::numeric_limits<unsigned int>::max()), 0169 mPosition(), 0170 mDistance(std::numeric_limits<ai_real>::max()) { 0171 // empty 0172 } 0173 Entry(unsigned int pIndex, const aiVector3D &pPosition) : 0174 mIndex(pIndex), mPosition(pPosition), mDistance(std::numeric_limits<ai_real>::max()) { 0175 // empty 0176 } 0177 0178 bool operator<(const Entry &e) const { return mDistance < e.mDistance; } 0179 }; 0180 0181 // all positions, sorted by distance to the sorting plane 0182 std::vector<Entry> mPositions; 0183 0184 /// false until the Finalize method is called. 0185 bool mFinalized; 0186 }; 0187 0188 } // end of namespace Assimp 0189 0190 #endif // AI_SPATIALSORT_H_INC
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