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vcglib/vcg/complex/algorithms/voronoi_clustering.h

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/****************************************************************************
* MeshLab o o *
* A versatile mesh processing toolbox o o *
* _ O _ *
* Copyright(C) 2005 \/)\/ *
* Visual Computing Lab /\/| *
* ISTI - Italian National Research Council | *
* \ *
* All rights reserved. *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
* for more details. *
* *
****************************************************************************/
#ifndef VORONOI_PROCESSING_H
#define VORONOI_PROCESSING_H
//#include <vcg/simplex/face/topology.h>
#include <vcg/complex/algorithms/geodesic.h>
#include <vcg/complex/algorithms/update/color.h>
namespace vcg
{
namespace tri
{
template <class MeshType>
class ClusteringSampler
{
public:
typedef typename MeshType::VertexType VertexType;
ClusteringSampler()
{
sampleVec=0;
}
ClusteringSampler(std::vector<VertexType *> *_vec)
{
sampleVec = _vec;
}
std::vector<VertexType *> *sampleVec;
void AddVert(const VertexType &p)
{
sampleVec->push_back((VertexType *)(&p));
}
}; // end class ClusteringSampler
template <class MeshType >
class VoronoiProcessing
{
typedef typename MeshType::CoordType CoordType;
typedef typename MeshType::ScalarType ScalarType;
typedef typename MeshType::VertexType VertexType;
typedef typename MeshType::VertexPointer VertexPointer;
typedef typename MeshType::VertexIterator VertexIterator;
typedef typename MeshType::FacePointer FacePointer;
typedef typename MeshType::FaceIterator FaceIterator;
typedef typename MeshType::FaceType FaceType;
typedef typename MeshType::FaceContainer FaceContainer;
public:
// Given a vector of point3f it finds the closest vertices on the mesh.
static void SeedToVertexConversion(MeshType &m,std::vector<CoordType> &seedPVec,std::vector<VertexType *> &seedVVec)
{
typedef typename vcg::SpatialHashTable<VertexType, ScalarType> HashVertexGrid;
seedVVec.clear();
HashVertexGrid HG;
HG.Set(m.vert.begin(),m.vert.end());
const float dist_upper_bound=m.bbox.Diag()/10.0;
typename std::vector<CoordType>::iterator pi;
for(pi=seedPVec.begin();pi!=seedPVec.end();++pi)
{
float dist;
VertexPointer vp;
vp=tri::GetClosestVertex<MeshType,HashVertexGrid>(m, HG, *pi, dist_upper_bound, dist);
if(vp)
{
seedVVec.push_back(vp);
}
}
}
typedef typename MeshType::template PerVertexAttributeHandle<VertexPointer> PerVertexPointerHandle;
typedef typename MeshType::template PerFaceAttributeHandle<VertexPointer> PerFacePointerHandle;
static void ComputePerVertexSources(MeshType &m, std::vector<VertexType *> &seedVec)
{
tri::Geo<MeshType> g;
VertexPointer farthest;
tri::Allocator<MeshType>::DeletePerVertexAttribute(m,"sources"); // delete any conflicting handle regardless of the type...
PerVertexPointerHandle vertexSources = tri::Allocator<MeshType>:: template AddPerVertexAttribute<VertexPointer> (m,"sources");
tri::Allocator<MeshType>::DeletePerFaceAttribute(m,"sources"); // delete any conflicting handle regardless of the type...
PerFacePointerHandle faceSources = tri::Allocator<MeshType>:: template AddPerFaceAttribute<VertexPointer> (m,"sources");
assert(tri::Allocator<MeshType>::IsValidHandle(m,vertexSources));
g.FarthestVertex(m,seedVec,farthest,std::numeric_limits<ScalarType>::max(),&vertexSources);
}
static void VoronoiColoring(MeshType &m, std::vector<VertexType *> &seedVec, bool frontierFlag=true)
{
PerVertexPointerHandle sources = tri::Allocator<MeshType>:: template GetPerVertexAttribute<VertexPointer> (m,"sources");
assert(tri::Allocator<MeshType>::IsValidHandle(m,sources));
tri::Geo<MeshType> g;
VertexPointer farthest;
if(frontierFlag)
{
std::pair<float,VertexPointer> zz(0,0);
std::vector< std::pair<float,VertexPointer> > regionArea(m.vert.size(),zz);
std::vector<VertexPointer> borderVec;
GetAreaAndFrontier(m, sources, regionArea, borderVec);
g.FarthestVertex(m,borderVec,farthest);
}
tri::UpdateColor<MeshType>::VertexQualityRamp(m);
}
// It associates the faces with a given vertex according to the vertex associations
//
// It READS the PerVertex attribute 'sources'
// It WRITES the PerFace attribute 'sources'
static void FaceAssociateRegion(MeshType &m)
{
PerFacePointerHandle faceSources = tri::Allocator<MeshType>:: template GetPerFaceAttribute<VertexPointer> (m,"sources");
PerVertexPointerHandle vertexSources = tri::Allocator<MeshType>:: template GetPerVertexAttribute<VertexPointer> (m,"sources");
for(FaceIterator fi=m.face.begin();fi!=m.face.end();++fi)
{
faceSources[fi]=0;
std::vector<VertexPointer> vp(3);
for(int i=0;i<3;++i) vp[i]=vertexSources[fi->V(i)];
for(int i=0;i<3;++i) // First try to associate to the most reached vertex
{
if(vp[0]==vp[1] && vp[0]==vp[2]) faceSources[fi] = vp[0];
else
{
if(vp[0]==vp[1] && vp[0]->Q()< vp[2]->Q()) faceSources[fi] = vp[0];
if(vp[0]==vp[2] && vp[0]->Q()< vp[1]->Q()) faceSources[fi] = vp[0];
if(vp[1]==vp[2] && vp[1]->Q()< vp[0]->Q()) faceSources[fi] = vp[1];
}
}
}
tri::UpdateTopology<MeshType>::FaceFace(m);
int unassCnt=0;
do
{
unassCnt=0;
for(FaceIterator fi=m.face.begin();fi!=m.face.end();++fi)
{
if(faceSources[fi]==0)
{
std::vector<VertexPointer> vp(3);
for(int i=0;i<3;++i)
vp[i]=faceSources[fi->FFp(i)];
if(vp[0]!=0 && (vp[0]==vp[1] || vp[0]==vp[2]))
faceSources[fi] = vp[0];
else if(vp[1]!=0 && (vp[1]==vp[2]))
faceSources[fi] = vp[1];
else
faceSources[fi] = std::max(vp[0],std::max(vp[1],vp[2]));
if(faceSources[fi]==0) unassCnt++;
}
}
}
while(unassCnt>0);
}
// Select all the faces with a given source vertex <vp>
// It reads the PerFace attribute 'sources'
static int FaceSelectAssociateRegion(MeshType &m, VertexPointer vp)
{
PerFacePointerHandle sources = tri::Allocator<MeshType>:: template GetPerFaceAttribute<VertexPointer> (m,"sources");
assert(tri::Allocator<MeshType>::IsValidHandle(m,sources));
tri::UpdateSelection<MeshType>::Clear(m);
int selCnt=0;
for(FaceIterator fi=m.face.begin();fi!=m.face.end();++fi)
{
if(sources[fi]==vp)
{
fi->SetS();
++selCnt;
}
}
return selCnt;
}
// Given a seed <vp>, it selects all the faces that have the minimal distance vertex sourced by the given <vp>.
// <vp> can be null (it search for unreached faces...)
// returns the number of selected faces;
//
// It reads the PerVertex attribute 'sources'
static int FaceSelectRegion(MeshType &m, VertexPointer vp)
{
PerVertexPointerHandle sources = tri::Allocator<MeshType>:: template GetPerVertexAttribute<VertexPointer> (m,"sources");
assert(tri::Allocator<MeshType>::IsValidHandle(m,sources));
tri::UpdateSelection<MeshType>::Clear(m);
int selCnt=0;
for(FaceIterator fi=m.face.begin();fi!=m.face.end();++fi)
{
int minInd = 0; float minVal=std::numeric_limits<float>::max();
for(int i=0;i<3;++i)
{
if((*fi).V(i)->Q()<minVal)
{
minInd=i;
minVal=(*fi).V(i)->Q();
}
}
if( sources[(*fi).V(minInd)] == vp)
{
fi->SetS();
selCnt++;
}
}
return selCnt;
}
// find the vertexes of frontier faces
// and compute Area of all the regions
static void GetAreaAndFrontier(MeshType &m, PerVertexPointerHandle &sources,
std::vector< std::pair<float,VertexPointer> > &regionArea,
std::vector<VertexPointer> &borderVec)
{
tri::UpdateFlags<MeshType>::VertexClearV(m);
for(FaceIterator fi=m.face.begin();fi!=m.face.end();++fi)
{
if( sources[(*fi).V(0)] != sources[(*fi).V(1)] ||
sources[(*fi).V(0)] != sources[(*fi).V(2)] )
{
for(int i=0;i<3;++i)
{
(*fi).V(i)->SetV();
(*fi).V(i)->C() = Color4b::Black;
}
}
else // the face belongs to a single region; accumulate area;
{
if(sources[(*fi).V(0)] != 0)
{
int seedIndex = sources[(*fi).V(0)] - &*m.vert.begin();
regionArea[seedIndex].first+=DoubleArea(*fi);
regionArea[seedIndex].second=sources[(*fi).V(0)];
}
}
}
// Collect the frontier vertexes
borderVec.clear();
for(VertexIterator vi=m.vert.begin();vi!=m.vert.end();++vi)
if((*vi).IsV()) borderVec.push_back(&*vi);
}
static void VoronoiRelaxing(MeshType &m, std::vector<VertexType *> &seedVec, int relaxIter, int /*percentileClamping*/, vcg::CallBackPos *cb=0)
{
for(int iter=0;iter<relaxIter;++iter)
{
if(cb) cb(iter*100/relaxIter,"Voronoi Lloyd Relaxation: First Partitioning");
tri::Geo<MeshType> g;
VertexPointer farthest;
// first run: find for each point what is the closest to one of the seeds.
typename MeshType::template PerVertexAttributeHandle<VertexPointer> sources;
sources = tri::Allocator<MeshType>:: template AddPerVertexAttribute<VertexPointer> (m,"sources");
g.FarthestVertex(m,seedVec,farthest,std::numeric_limits<ScalarType>::max(),&sources);
std::pair<float,VertexPointer> zz(0,0);
std::vector< std::pair<float,VertexPointer> > regionArea(m.vert.size(),zz);
std::vector<VertexPointer> borderVec;
GetAreaAndFrontier(m, sources, regionArea, borderVec);
// Smaller area region are discarded
Distribution<float> H;
for(size_t i=0;i<regionArea.size();++i)
if(regionArea[i].second) H.Add(regionArea[i].first);
float areaThreshold;
if(iter==0) areaThreshold = H.Percentile(.1f);
else areaThreshold = H.Percentile(.001f);
//qDebug("We have found %i regions range (%f %f), avg area is %f, Variance is %f 10perc is %f",(int)seedVec.size(),H.Min(),H.Max(),H.Avg(),H.StandardDeviation(),areaThreshold);
if(cb) cb(iter*100/relaxIter,"Voronoi Lloyd Relaxation: Searching New Seeds");
g.FarthestVertex(m,borderVec,farthest);
tri::UpdateColor<MeshType>::VertexQualityRamp(m);
// Search the local maxima for each region and use them as new seeds
std::vector< std::pair<float,VertexPointer> > seedMaxima(m.vert.size(),zz);
for(VertexIterator vi=m.vert.begin();vi!=m.vert.end();++vi)
{
int seedIndex = sources[vi] - &*m.vert.begin();
if(seedMaxima[seedIndex].first < (*vi).Q())
{
seedMaxima[seedIndex].first=(*vi).Q();
seedMaxima[seedIndex].second=&*vi;
}
}
std::vector<VertexPointer> newSeeds;
for(size_t i=0;i<seedMaxima.size();++i)
if(seedMaxima[i].second)
{
seedMaxima[i].second->C() = Color4b::Gray;
if(regionArea[i].first >= areaThreshold)
newSeeds.push_back(seedMaxima[i].second);
}
tri::UpdateColor<MeshType>::VertexQualityRamp(m);
for(size_t i=0;i<seedVec.size();++i)
seedVec[i]->C() = Color4b::Black;
for(size_t i=0;i<borderVec.size();++i)
borderVec[i]->C() = Color4b::Gray;
swap(newSeeds,seedVec);
for(size_t i=0;i<seedVec.size();++i)
seedVec[i]->C() = Color4b::White;
tri::Allocator<MeshType>::DeletePerVertexAttribute (m,"sources");
}
}
// Base vertex voronoi coloring algorithm.
// it assumes VF adjacency. No attempt of computing real geodesic distnace is done. Just a BFS visit starting from the seeds.
static void TopologicalVertexColoring(MeshType &m, std::vector<VertexType *> &seedVec)
{
std::queue<VertexPointer> VQ;
tri::UpdateQuality<MeshType>::VertexConstant(m,0);
for(size_t i=0;i<seedVec.size();++i)
{
VQ.push(seedVec[i]);
seedVec[i]->Q()=i+1;
}
while(!VQ.empty())
{
VertexPointer vp = VQ.front();
VQ.pop();
std::vector<VertexPointer> vertStar;
vcg::face::VVStarVF<FaceType>(vp,vertStar);
for(typename std::vector<VertexPointer>::iterator vv = vertStar.begin();vv!=vertStar.end();++vv)
{
if((*vv)->Q()==0)
{
(*vv)->Q()=vp->Q();
VQ.push(*vv);
}
}
} // end while(!VQ.empty())
}
// Drastic Simplification algorithm.
// Similar in philosopy to the classic grid clustering but using a voronoi partition instead of the regular grid.
//
// This function assumes that in the mOld mesh, for each vertex you have a quality that denotes the index of the cluster
// mNew is created by collasping onto a single vertex all the vertices that lies in the same cluster.
// Non degenerate triangles are preserved.
static void VoronoiClustering(MeshType &mOld, MeshType &mNew, std::vector<VertexType *> &seedVec)
{
std::set<Point3i> clusteredFace;
FaceIterator fi;
for(fi=mOld.face.begin();fi!=mOld.face.end();++fi)
{
if( (fi->V(0)->Q() != fi->V(1)->Q() ) &&
(fi->V(0)->Q() != fi->V(2)->Q() ) &&
(fi->V(1)->Q() != fi->V(2)->Q() ) )
clusteredFace.insert( Point3i(int(fi->V(0)->Q()), int(fi->V(1)->Q()), int(fi->V(2)->Q())));
}
tri::Allocator<MeshType>::AddVertices(mNew,seedVec.size());
for(size_t i=0;i< seedVec.size();++i)
mNew.vert[i].ImportLocal(*(seedVec[i]));
tri::Allocator<MeshType>::AddFaces(mNew,clusteredFace.size());
std::set<Point3i>::iterator fsi; ;
for(fi=mNew.face.begin(),fsi=clusteredFace.begin(); fsi!=clusteredFace.end();++fsi,++fi)
{
(*fi).V(0) = & mNew.vert[(int)(fsi->V(0)-1)];
(*fi).V(1) = & mNew.vert[(int)(fsi->V(1)-1)];
(*fi).V(2) = & mNew.vert[(int)(fsi->V(2)-1)];
}
}
}; // end class VoronoiProcessing
} // end namespace tri
} // end namespace vcg
#endif
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