191 lines
8.6 KiB
C++
191 lines
8.6 KiB
C++
/*
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Open Asset Import Library (assimp)
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----------------------------------------------------------------------
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Copyright (c) 2006-2024, assimp team
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All rights reserved.
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Redistribution and use of this software in source and binary forms,
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with or without modification, are permitted provided that the
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following conditions are met:
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* Redistributions of source code must retain the above
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copyright notice, this list of conditions and the
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following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the
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following disclaimer in the documentation and/or other
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materials provided with the distribution.
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* Neither the name of the assimp team, nor the names of its
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contributors may be used to endorse or promote products
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derived from this software without specific prior
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written permission of the assimp team.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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----------------------------------------------------------------------
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*/
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/** Small helper classes to optimise finding vertizes close to a given location */
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#pragma once
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#ifndef AI_SPATIALSORT_H_INC
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#define AI_SPATIALSORT_H_INC
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#ifdef __GNUC__
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#pragma GCC system_header
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#endif
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#include <assimp/types.h>
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#include <vector>
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#include <limits>
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namespace Assimp {
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// ------------------------------------------------------------------------------------------------
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/** A little helper class to quickly find all vertices in the epsilon environment of a given
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* position. Construct an instance with an array of positions. The class stores the given positions
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* by their indices and sorts them by their distance to an arbitrary chosen plane.
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* You can then query the instance for all vertices close to a given position in an average O(log n)
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* time, with O(n) worst case complexity when all vertices lay on the plane. The plane is chosen
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* so that it avoids common planes in usual data sets. */
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// ------------------------------------------------------------------------------------------------
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class ASSIMP_API SpatialSort {
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public:
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SpatialSort();
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// ------------------------------------------------------------------------------------
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/** Constructs a spatially sorted representation from the given position array.
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* Supply the positions in its layout in memory, the class will only refer to them
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* by index.
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* @param pPositions Pointer to the first position vector of the array.
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* @param pNumPositions Number of vectors to expect in that array.
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* @param pElementOffset Offset in bytes from the beginning of one vector in memory
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* to the beginning of the next vector. */
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SpatialSort(const aiVector3D *pPositions, unsigned int pNumPositions,
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unsigned int pElementOffset);
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/** Destructor */
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~SpatialSort();
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// ------------------------------------------------------------------------------------
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/** Sets the input data for the SpatialSort. This replaces existing data, if any.
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* The new data receives new indices in ascending order.
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*
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* @param pPositions Pointer to the first position vector of the array.
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* @param pNumPositions Number of vectors to expect in that array.
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* @param pElementOffset Offset in bytes from the beginning of one vector in memory
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* to the beginning of the next vector.
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* @param pFinalize Specifies whether the SpatialSort's internal representation
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* is finalized after the new data has been added. Finalization is
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* required in order to use #FindPosition() or #GenerateMappingTable().
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* If you don't finalize yet, you can use #Append() to add data from
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* other sources.*/
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void Fill(const aiVector3D *pPositions, unsigned int pNumPositions,
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unsigned int pElementOffset,
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bool pFinalize = true);
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// ------------------------------------------------------------------------------------
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/** Same as #Fill(), except the method appends to existing data in the #SpatialSort. */
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void Append(const aiVector3D *pPositions, unsigned int pNumPositions,
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unsigned int pElementOffset,
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bool pFinalize = true);
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// ------------------------------------------------------------------------------------
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/** Finalize the spatial hash data structure. This can be useful after
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* multiple calls to #Append() with the pFinalize parameter set to false.
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* This is finally required before one of #FindPositions() and #GenerateMappingTable()
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* can be called to query the spatial sort.*/
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void Finalize();
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// ------------------------------------------------------------------------------------
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/** Returns an iterator for all positions close to the given position.
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* @param pPosition The position to look for vertices.
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* @param pRadius Maximal distance from the position a vertex may have to be counted in.
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* @param poResults The container to store the indices of the found positions.
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* Will be emptied by the call so it may contain anything.
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* @return An iterator to iterate over all vertices in the given area.*/
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void FindPositions(const aiVector3D &pPosition, ai_real pRadius,
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std::vector<unsigned int> &poResults) const;
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// ------------------------------------------------------------------------------------
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/** Fills an array with indices of all positions identical to the given position. In
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* opposite to FindPositions(), not an epsilon is used but a (very low) tolerance of
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* four floating-point units.
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* @param pPosition The position to look for vertices.
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* @param poResults The container to store the indices of the found positions.
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* Will be emptied by the call so it may contain anything.*/
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void FindIdenticalPositions(const aiVector3D &pPosition,
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std::vector<unsigned int> &poResults) const;
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// ------------------------------------------------------------------------------------
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/** Compute a table that maps each vertex ID referring to a spatially close
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* enough position to the same output ID. Output IDs are assigned in ascending order
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* from 0...n.
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* @param fill Will be filled with numPositions entries.
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* @param pRadius Maximal distance from the position a vertex may have to
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* be counted in.
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* @return Number of unique vertices (n). */
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unsigned int GenerateMappingTable(std::vector<unsigned int> &fill,
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ai_real pRadius) const;
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protected:
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/** Return the distance to the sorting plane. */
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ai_real CalculateDistance(const aiVector3D &pPosition) const;
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protected:
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/** Normal of the sorting plane, normalized.
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*/
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aiVector3D mPlaneNormal;
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/** The centroid of the positions, which is used as a point on the sorting plane
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* when calculating distance. This value is calculated in Finalize.
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*/
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aiVector3D mCentroid;
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/** An entry in a spatially sorted position array. Consists of a vertex index,
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* its position and its pre-calculated distance from the reference plane */
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struct Entry {
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unsigned int mIndex; ///< The vertex referred by this entry
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aiVector3D mPosition; ///< Position
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/// Distance of this vertex to the sorting plane. This is set by Finalize.
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ai_real mDistance;
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Entry() AI_NO_EXCEPT
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: mIndex(std::numeric_limits<unsigned int>::max()),
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mPosition(),
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mDistance(std::numeric_limits<ai_real>::max()) {
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// empty
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}
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Entry(unsigned int pIndex, const aiVector3D &pPosition) :
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mIndex(pIndex), mPosition(pPosition), mDistance(std::numeric_limits<ai_real>::max()) {
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// empty
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}
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bool operator<(const Entry &e) const { return mDistance < e.mDistance; }
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};
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// all positions, sorted by distance to the sorting plane
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std::vector<Entry> mPositions;
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/// false until the Finalize method is called.
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bool mFinalized;
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};
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} // end of namespace Assimp
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#endif // AI_SPATIALSORT_H_INC
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