369 lines
12 KiB
C++
369 lines
12 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) 2006-2008, ASSIMP Development 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 Development 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 to improve the
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* 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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*/
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#include "AssimpPCH.h"
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// internal headers
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#include "ImproveCacheLocality.h"
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#include "VertexTriangleAdjacency.h"
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using namespace Assimp;
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#if _MSC_VER >= 1400
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# define sprintf sprintf_s
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#endif
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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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{
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// nothing to do here
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configCacheDepth = 12; // hardcoded to 12 at the moment
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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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{
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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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{
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return (pFlags & aiProcess_ImproveCacheLocality) != 0;
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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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{
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if (!pScene->mNumMeshes)
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{
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DefaultLogger::get()->debug("ImproveCacheLocalityProcess skipped; there are no meshes");
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return;
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}
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DefaultLogger::get()->debug("ImproveCacheLocalityProcess begin");
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for( unsigned int a = 0; a < pScene->mNumMeshes; a++)
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{
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this->ProcessMesh( pScene->mMeshes[a],a);
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}
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DefaultLogger::get()->debug("ImproveCacheLocalityProcess finished. ");
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}
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// ------------------------------------------------------------------------------------------------
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// Improves the cache coherency of a specific mesh
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void ImproveCacheLocalityProcess::ProcessMesh( aiMesh* pMesh, unsigned int meshNum)
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{
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ai_assert(NULL != pMesh);
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// check whether the input data is valid ->
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// - there must be vertices and faces (haha)
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// - all faces must be triangulated
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if (!pMesh->HasFaces() || !pMesh->HasPositions())
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return;
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if (pMesh->mPrimitiveTypes != aiPrimitiveType_TRIANGLE)
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{
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DefaultLogger::get()->error("This algorithm works on triangle meshes only");
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return;
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}
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// find the input ACMR ...
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unsigned int* piFIFOStack = new unsigned int[this->configCacheDepth];
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::memset(piFIFOStack,0xff,this->configCacheDepth*sizeof(unsigned int));
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unsigned int* piCur = piFIFOStack;
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const unsigned int* const piCurEnd = piFIFOStack + this->configCacheDepth;
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// count the number of cache misses
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unsigned int iCacheMisses = 0;
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const aiFace* const pcEnd = pMesh->mFaces+pMesh->mNumFaces;
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for (const aiFace* pcFace = pMesh->mFaces;pcFace != pcEnd;++pcFace)
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{
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for (unsigned int qq = 0; qq < 3;++qq)
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{
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bool bInCache = false;
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for (unsigned int* pp = piFIFOStack;pp < piCurEnd;++pp)
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{
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if (*pp == pcFace->mIndices[qq])
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{
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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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{
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++iCacheMisses;
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if (piCurEnd == piCur)piCur = piFIFOStack;
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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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float fACMR = (float)iCacheMisses / pMesh->mNumFaces;
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if (3.0 == fACMR)
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{
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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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::sprintf(szBuff,"Mesh %i: JIV-Step has not been executed properly (precondition)",meshNum);
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DefaultLogger::get()->warn(szBuff);
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return;
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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
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// indices in one large array. Since the number of triangles
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// won't change the input faces can be reused. This is how we save
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// 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> 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 unsigned int* const piNumTriPtrNoModify = new unsigned int[pMesh->mNumVertices];
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::memcpy(const_cast<unsigned int* const> (piNumTriPtrNoModify),piNumTriPtr,
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pMesh->mNumVertices * sizeof(unsigned int));
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// get the largest number of referenced triangles
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// and allocate the "candidate buffer"
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unsigned int iMaxRefTris = 0;
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{
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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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unsigned int* piCandidates = new unsigned int[iMaxRefTris*3];
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iCacheMisses = 0;
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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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int ivdx = 0;
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int ics = 1;
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int iStampCnt = this->configCacheDepth+1;
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while (ivdx >= 0)
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{
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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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{
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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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{
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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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const unsigned int* const p2 = pcFace->mIndices+3;
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for (unsigned int* p = pcFace->mIndices;p != p2;++p)
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{
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const unsigned int dp = *p;
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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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{
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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] > this->configCacheDepth)
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{
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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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{
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register 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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{
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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] <= this->configCacheDepth)
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priority = tmp;
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// keep best candidate
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if (priority > max_priority)
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{
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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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{
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// need to get a non-local vertex for which we have a good
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// chance that it is still in the cache ...
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while (!sDeadEndVStack.empty())
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{
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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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{
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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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{
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// well, there isn't such a vertex. Simply get the next
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// vertex in input order and hope it is not too bad ...
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while (ics < (int)pMesh->mNumVertices)
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{
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++ics;
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if (piNumTriPtr[ics] > 0)
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{
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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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if (!DefaultLogger::isNullLogger())
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{
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char szBuff[128]; // should be sufficiently large in every case
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float fACMR2 = (float)iCacheMisses / pMesh->mNumFaces;
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::sprintf(szBuff,"Mesh %i | ACMR in: %f out: %f | ~%.1f%%",meshNum,fACMR,fACMR2,
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((fACMR - fACMR2) / fACMR) * 100.f);
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DefaultLogger::get()->info(szBuff);
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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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{
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pcFace->mIndices[0] = *piCSIter++;
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pcFace->mIndices[1] = *piCSIter++;
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pcFace->mIndices[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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delete[] piNumTriPtrNoModify;
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}
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