alexpete
96 lines
3.5 KiB
C++
96 lines
3.5 KiB
C++
/*
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* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
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* its licensors.
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*
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* For complete copyright and license terms please see the LICENSE at the root of this
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* distribution (the "License"). All use of this software is governed by the License,
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* or, if provided, by the license below or the license accompanying this file. Do not
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* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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*
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*/
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// Original file Copyright Crytek GMBH or its affiliates, used under license.
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#pragma once
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#include <vector>
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#include <BaseTypes.h>
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#include "CompileTimeAssert.h"
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//
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// Note: This implementation, in contrast to many other implementations
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// of the Forsyth's algorithm, does not crash when the input faces contain
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// duplicate indices, for example (8,3,8) or (1,1,9).
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//
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class ForsythFaceReorderer
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{
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public:
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static const size_t sk_maxCacheSize = 50; // you can change it. note: making it higher will increase sizeof(*this)
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static const size_t sk_minVerticesPerFace = 3;
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static const size_t sk_maxVerticesPerFace = 4;
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COMPILE_TIME_ASSERT(sk_minVerticesPerFace >= 3); // Bad min # of vertices per face
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COMPILE_TIME_ASSERT(sk_minVerticesPerFace <= sk_maxVerticesPerFace); // Bad # of vertices per face
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COMPILE_TIME_ASSERT(sk_maxVerticesPerFace <= sk_maxCacheSize); // Bad max cache size
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private:
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typedef uint16 valency_type;
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static const valency_type sk_maxValency = 0xFFFF;
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typedef int8 cachepos_type;
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static const cachepos_type sk_maxCachePos = 127;
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struct Vertex
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{
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uint32* m_pFaceList;
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valency_type m_aliveFaceCount;
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cachepos_type m_posInCache;
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float m_score;
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};
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static const size_t sk_valencyTableSize = 32; // note: size_t is used instead of valency_type because valency_type overflows if sk_valencyTableSize == 1 + sk_maxValency
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COMPILE_TIME_ASSERT(sk_valencyTableSize - 1 <= sk_maxValency); // Bad valency table size
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COMPILE_TIME_ASSERT(sk_maxCacheSize <= 1 + (size_t)sk_maxCachePos); // Max cache size is too big
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std::vector<Vertex> m_vertices;
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std::vector<uint8> m_deadFacesBitArray;
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std::vector<float> m_faceScores; // score of every face
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std::vector<uint32> m_vertexFaceLists; // lists with indices of faces (each vertex has own list)
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int m_cacheSize;
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int m_cacheUsedSize;
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uint32 m_cache[sk_maxCacheSize + sk_maxVerticesPerFace]; // +sk_maxVerticesPerFace is temporary storage for vertices of the incoming face
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float m_scoreTable_valency[sk_valencyTableSize];
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float m_scoreTable_cachePosition[sk_maxCacheSize];
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public:
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ForsythFaceReorderer();
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// notes:
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// 1) it's not allowed to pass same array for inVertexIndices and outVertexIndices
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// 2) outFaceToOldFace is optional (pass 0 if you don't need this array filled)
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bool reorderFaces(
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const size_t cacheSize,
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const uint verticesPerFace,
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const size_t indexCount,
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const uint32* const inVertexIndices,
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uint32* const outVertexIndices,
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uint32* const outFaceToOldFace);
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private:
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void clear();
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void computeCacheScoreTable(const int verticesPerFace);
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void computeValencyScoreTable();
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void computeVertexScore(Vertex& v);
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void moveVertexToCacheTop(const uint32 vertexIndex);
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void removeFaceFromVertex(const uint32 vertexIndex, const uint32 faceIndex);
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uint32 findBestFaceToAdd(uint32& faceSearchCursor) const;
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};
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