379 lines
15 KiB
C++
379 lines
15 KiB
C++
/*
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---------------------------------------------------------------------------
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Open Asset Import Library (assimp)
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---------------------------------------------------------------------------
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Copyright (c) 2006-2020, 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 following
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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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/** @file Implementation of the post processing step to improve the cache locality of a mesh.
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* <br>
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* The algorithm is roughly basing on this paper:
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* http://www.cs.princeton.edu/gfx/pubs/Sander_2007_%3ETR/tipsy.pdf
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* .. although overdraw reduction isn't implemented yet ...
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*/
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// internal headers
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#include "PostProcessing/ImproveCacheLocality.h"
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#include "Common/VertexTriangleAdjacency.h"
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#include <assimp/StringUtils.h>
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#include <assimp/postprocess.h>
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#include <assimp/scene.h>
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#include <assimp/DefaultLogger.hpp>
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#include <stdio.h>
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#include <stack>
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using namespace Assimp;
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// ------------------------------------------------------------------------------------------------
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// Constructor to be privately used by Importer
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ImproveCacheLocalityProcess::ImproveCacheLocalityProcess()
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: mConfigCacheDepth(PP_ICL_PTCACHE_SIZE) {
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// empty
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}
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// ------------------------------------------------------------------------------------------------
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// Destructor, private as well
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ImproveCacheLocalityProcess::~ImproveCacheLocalityProcess() {
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// nothing to do here
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}
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// ------------------------------------------------------------------------------------------------
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// Returns whether the processing step is present in the given flag field.
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bool ImproveCacheLocalityProcess::IsActive( unsigned int pFlags) const {
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return (pFlags & aiProcess_ImproveCacheLocality) != 0;
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}
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// ------------------------------------------------------------------------------------------------
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// Setup configuration
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void ImproveCacheLocalityProcess::SetupProperties(const Importer* pImp) {
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// AI_CONFIG_PP_ICL_PTCACHE_SIZE controls the target cache size for the optimizer
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mConfigCacheDepth = pImp->GetPropertyInteger(AI_CONFIG_PP_ICL_PTCACHE_SIZE,PP_ICL_PTCACHE_SIZE);
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}
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// ------------------------------------------------------------------------------------------------
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// Executes the post processing step on the given imported data.
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void ImproveCacheLocalityProcess::Execute( aiScene* pScene) {
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if (!pScene->mNumMeshes) {
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ASSIMP_LOG_DEBUG("ImproveCacheLocalityProcess skipped; there are no meshes");
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return;
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}
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ASSIMP_LOG_DEBUG("ImproveCacheLocalityProcess begin");
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float out = 0.f;
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unsigned int numf = 0, numm = 0;
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for( unsigned int a = 0; a < pScene->mNumMeshes; ++a ){
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const float res = ProcessMesh( pScene->mMeshes[a],a);
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if (res) {
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numf += pScene->mMeshes[a]->mNumFaces;
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out += res;
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++numm;
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}
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}
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if (!DefaultLogger::isNullLogger()) {
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if (numf > 0) {
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ASSIMP_LOG_INFO_F("Cache relevant are ", numm, " meshes (", numf, " faces). Average output ACMR is ", out / numf);
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}
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ASSIMP_LOG_DEBUG("ImproveCacheLocalityProcess finished. ");
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}
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}
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// ------------------------------------------------------------------------------------------------
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// Improves the cache coherency of a specific mesh
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ai_real ImproveCacheLocalityProcess::ProcessMesh( aiMesh* pMesh, unsigned int meshNum) {
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// TODO: rewrite this to use std::vector or boost::shared_array
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ai_assert(nullptr != pMesh);
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// Check whether the input data is valid
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// - there must be vertices and faces
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// - all faces must be triangulated or we can't operate on them
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if (!pMesh->HasFaces() || !pMesh->HasPositions())
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return static_cast<ai_real>(0.f);
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if (pMesh->mPrimitiveTypes != aiPrimitiveType_TRIANGLE) {
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ASSIMP_LOG_ERROR("This algorithm works on triangle meshes only");
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return static_cast<ai_real>(0.f);
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}
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if(pMesh->mNumVertices <= mConfigCacheDepth) {
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return static_cast<ai_real>(0.f);
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}
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ai_real fACMR = 3.f;
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const aiFace* const pcEnd = pMesh->mFaces+pMesh->mNumFaces;
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// Input ACMR is for logging purposes only
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if (!DefaultLogger::isNullLogger()) {
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unsigned int* piFIFOStack = new unsigned int[mConfigCacheDepth];
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memset(piFIFOStack,0xff,mConfigCacheDepth*sizeof(unsigned int));
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unsigned int* piCur = piFIFOStack;
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const unsigned int* const piCurEnd = piFIFOStack + mConfigCacheDepth;
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// count the number of cache misses
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unsigned int iCacheMisses = 0;
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for (const aiFace* pcFace = pMesh->mFaces;pcFace != pcEnd;++pcFace) {
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for (unsigned int qq = 0; qq < 3;++qq) {
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bool bInCache = false;
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for (unsigned int* pp = piFIFOStack;pp < piCurEnd;++pp) {
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if (*pp == pcFace->mIndices[qq]) {
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// the vertex is in cache
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bInCache = true;
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break;
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}
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}
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if (!bInCache) {
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++iCacheMisses;
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if (piCurEnd == piCur) {
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piCur = piFIFOStack;
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}
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*piCur++ = pcFace->mIndices[qq];
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}
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}
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}
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delete[] piFIFOStack;
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fACMR = (ai_real) iCacheMisses / pMesh->mNumFaces;
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if (3.0 == fACMR) {
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char szBuff[128]; // should be sufficiently large in every case
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// the JoinIdenticalVertices process has not been executed on this
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// mesh, otherwise this value would normally be at least minimally
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// smaller than 3.0 ...
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ai_snprintf(szBuff,128,"Mesh %u: Not suitable for vcache optimization",meshNum);
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ASSIMP_LOG_WARN(szBuff);
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return static_cast<ai_real>(0.f);
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}
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}
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// first we need to build a vertex-triangle adjacency list
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VertexTriangleAdjacency adj(pMesh->mFaces,pMesh->mNumFaces, pMesh->mNumVertices,true);
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// build a list to store per-vertex caching time stamps
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unsigned int* const piCachingStamps = new unsigned int[pMesh->mNumVertices];
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memset(piCachingStamps,0x0,pMesh->mNumVertices*sizeof(unsigned int));
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// allocate an empty output index buffer. We store the output indices in one large array.
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// Since the number of triangles won't change the input faces can be reused. This is how
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// we save thousands of redundant mini allocations for aiFace::mIndices
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const unsigned int iIdxCnt = pMesh->mNumFaces*3;
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unsigned int* const piIBOutput = new unsigned int[iIdxCnt];
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unsigned int* piCSIter = piIBOutput;
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// allocate the flag array to hold the information
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// whether a face has already been emitted or not
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std::vector<bool> abEmitted(pMesh->mNumFaces,false);
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// dead-end vertex index stack
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std::stack<unsigned int, std::vector<unsigned int> > sDeadEndVStack;
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// create a copy of the piNumTriPtr buffer
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unsigned int* const piNumTriPtr = adj.mLiveTriangles;
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const std::vector<unsigned int> piNumTriPtrNoModify(piNumTriPtr, piNumTriPtr + pMesh->mNumVertices);
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// get the largest number of referenced triangles and allocate the "candidate buffer"
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unsigned int iMaxRefTris = 0; {
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const unsigned int* piCur = adj.mLiveTriangles;
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const unsigned int* const piCurEnd = adj.mLiveTriangles+pMesh->mNumVertices;
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for (;piCur != piCurEnd;++piCur) {
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iMaxRefTris = std::max(iMaxRefTris,*piCur);
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}
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}
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ai_assert(iMaxRefTris > 0);
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unsigned int* piCandidates = new unsigned int[iMaxRefTris*3];
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unsigned int iCacheMisses = 0;
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// ...................................................................................
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/** PSEUDOCODE for the algorithm
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A = Build-Adjacency(I) Vertex-triangle adjacency
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L = Get-Triangle-Counts(A) Per-vertex live triangle counts
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C = Zero(Vertex-Count(I)) Per-vertex caching time stamps
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D = Empty-Stack() Dead-end vertex stack
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E = False(Triangle-Count(I)) Per triangle emitted flag
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O = Empty-Index-Buffer() Empty output buffer
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f = 0 Arbitrary starting vertex
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s = k+1, i = 1 Time stamp and cursor
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while f >= 0 For all valid fanning vertices
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N = Empty-Set() 1-ring of next candidates
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for each Triangle t in Neighbors(A, f)
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if !Emitted(E,t)
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for each Vertex v in t
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Append(O,v) Output vertex
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Push(D,v) Add to dead-end stack
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Insert(N,v) Register as candidate
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L[v] = L[v]-1 Decrease live triangle count
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if s-C[v] > k If not in cache
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C[v] = s Set time stamp
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s = s+1 Increment time stamp
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E[t] = true Flag triangle as emitted
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Select next fanning vertex
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f = Get-Next-Vertex(I,i,k,N,C,s,L,D)
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return O
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*/
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// ...................................................................................
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int ivdx = 0;
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int ics = 1;
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int iStampCnt = mConfigCacheDepth+1;
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while (ivdx >= 0) {
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unsigned int icnt = piNumTriPtrNoModify[ivdx];
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unsigned int* piList = adj.GetAdjacentTriangles(ivdx);
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unsigned int* piCurCandidate = piCandidates;
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// get all triangles in the neighborhood
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for (unsigned int tri = 0; tri < icnt;++tri) {
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// if they have not yet been emitted, add them to the output IB
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const unsigned int fidx = *piList++;
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if (!abEmitted[fidx]) {
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// so iterate through all vertices of the current triangle
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const aiFace* pcFace = &pMesh->mFaces[ fidx ];
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unsigned nind = pcFace->mNumIndices;
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for (unsigned ind = 0; ind < nind; ind++) {
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unsigned dp = pcFace->mIndices[ind];
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// the current vertex won't have any free triangles after this step
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if (ivdx != (int)dp) {
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// append the vertex to the dead-end stack
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sDeadEndVStack.push(dp);
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// register as candidate for the next step
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*piCurCandidate++ = dp;
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// decrease the per-vertex triangle counts
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piNumTriPtr[dp]--;
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}
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// append the vertex to the output index buffer
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*piCSIter++ = dp;
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// if the vertex is not yet in cache, set its cache count
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if (iStampCnt-piCachingStamps[dp] > mConfigCacheDepth) {
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piCachingStamps[dp] = iStampCnt++;
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++iCacheMisses;
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}
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}
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// flag triangle as emitted
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abEmitted[fidx] = true;
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}
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}
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// the vertex has now no living adjacent triangles anymore
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piNumTriPtr[ivdx] = 0;
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// get next fanning vertex
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ivdx = -1;
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int max_priority = -1;
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for (unsigned int* piCur = piCandidates;piCur != piCurCandidate;++piCur) {
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const unsigned int dp = *piCur;
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// must have live triangles
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if (piNumTriPtr[dp] > 0) {
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int priority = 0;
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// will the vertex be in cache, even after fanning occurs?
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unsigned int tmp;
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if ((tmp = iStampCnt-piCachingStamps[dp]) + 2*piNumTriPtr[dp] <= mConfigCacheDepth) {
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priority = tmp;
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}
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// keep best candidate
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if (priority > max_priority) {
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max_priority = priority;
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ivdx = dp;
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}
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}
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}
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// did we reach a dead end?
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if (-1 == ivdx) {
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// need to get a non-local vertex for which we have a good chance that it is still
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// in the cache ...
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while (!sDeadEndVStack.empty()) {
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unsigned int iCachedIdx = sDeadEndVStack.top();
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sDeadEndVStack.pop();
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if (piNumTriPtr[ iCachedIdx ] > 0) {
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ivdx = iCachedIdx;
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break;
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}
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}
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if (-1 == ivdx) {
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// well, there isn't such a vertex. Simply get the next vertex in input order and
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// hope it is not too bad ...
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while (ics < (int)pMesh->mNumVertices) {
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++ics;
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if (piNumTriPtr[ics] > 0) {
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ivdx = ics;
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break;
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}
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}
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}
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}
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}
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ai_real fACMR2 = 0.0f;
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if (!DefaultLogger::isNullLogger()) {
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fACMR2 = (float)iCacheMisses / pMesh->mNumFaces;
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// very intense verbose logging ... prepare for much text if there are many meshes
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if ( DefaultLogger::get()->getLogSeverity() == Logger::VERBOSE) {
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ASSIMP_LOG_DEBUG_F("Mesh %u | ACMR in: ", meshNum, " out: ", fACMR, " | ~", fACMR2, ((fACMR - fACMR2) / fACMR) * 100.f);
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}
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fACMR2 *= pMesh->mNumFaces;
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}
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// sort the output index buffer back to the input array
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piCSIter = piIBOutput;
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for (aiFace* pcFace = pMesh->mFaces; pcFace != pcEnd;++pcFace) {
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unsigned nind = pcFace->mNumIndices;
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unsigned * ind = pcFace->mIndices;
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if (nind > 0) ind[0] = *piCSIter++;
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if (nind > 1) ind[1] = *piCSIter++;
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if (nind > 2) ind[2] = *piCSIter++;
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}
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// delete temporary storage
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delete[] piCachingStamps;
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delete[] piIBOutput;
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delete[] piCandidates;
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return fACMR2;
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}
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