vcglib/vcg/complex/algorithms/local_optimization/tetra_edge_collapse.h

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/****************************************************************************
* VCGLib o o *
* Visual and Computer Graphics Library o o *
* _ O _ *
* Copyright(C) 2004 \/)\/ *
* 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. *
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****************************************************************************/
/****************************************************************************
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****************************************************************************/
#ifndef __VCG_DECIMATION_COLLAPSE
#define __VCG_DECIMATION_COLLAPSE
#include<vcg/complex/algorithms/local_optimization.h>
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#include<vcg/simplex/tetrahedron/pos.h>
#include<vcg/complex/tetramesh/edge_collapse.h>
#include<vcg/space/point3.h>
struct FAIL{
static int VOL(){static int vol=0; return vol++;}
static int LKF(){static int lkf=0; return lkf++;}
static int LKE(){static int lke=0; return lke++;}
static int LKV(){static int lkv=0; return lkv++;}
static int OFD(){static int ofd=0; return ofd++;}
static int BOR(){static int bor=0; return bor++;}
};
namespace vcg{
namespace tetra{
/** \addtogroup tetramesh */
/*@{*/
/// This Class is specialization of LocalModification for the edge collapse
/// It wraps the atomic operation EdgeCollapse to be used in a optimizatin routine.
/// Note that it has knowledge of the heap of the class LocalOptimization because
/// it is responsible of updating it after a collapse has been performed
template<class TETRA_MESH_TYPE>
class TetraEdgeCollapse: public LocalOptimization<TETRA_MESH_TYPE>::LocModType
{
/// The tetrahedral mesh type
//typedef typename TETRA_MESH_TYPE TETRA_MESH_TYPE;
/// The tetrahedron type
typedef typename TETRA_MESH_TYPE::TetraType TetraType;
/// The vertex type
typedef typename TetraType::VertexType VertexType;
/// The coordinate type
typedef typename TetraType::VertexType::CoordType CoordType;
/// The scalar type
typedef typename TETRA_MESH_TYPE::VertexType::ScalarType ScalarType;
/////the base type class
//typedef typename vcg::tri::LocalModification LocalMod;
/// The HEdgePos type
typedef Pos<TetraType> PosType;
/// The HEdgePos Loop type
typedef PosLoop<TetraType> PosLType;
/// definition of the heap element
typedef typename LocalOptimization<TETRA_MESH_TYPE>::HeapElem HeapElem;
private:
///the new point that substitute the edge
Point3<ScalarType> _NewPoint;
///the pointer to edge collapser method
vcg::tetra::EdgeCollapse<TETRA_MESH_TYPE> _EC;
///mark for up_dating
static int& _Imark(){ static int im=0; return im;}
///the pos of collapse
PosType pos;
///pointer to vertex that remain
VertexType *vrem;
/// priority in the heap
ScalarType _priority;
public:
/// Default Constructor
TetraEdgeCollapse()
{}
///Constructor with postype
TetraEdgeCollapse(PosType p,int mark)
{
_Imark() = mark;
pos=p;
_priority = _AspectRatioMedia(p);
}
~TetraEdgeCollapse()
{}
private:
///Return the aspect Ratio media of the tetrahedrons
///that share the adge to collapse
ScalarType _AspectRatioMedia(PosType p)
{
PosLType posl=PosLType(p.T(),p.F(),p.E(),p.V());
posl.Reset();
int num=0;
ScalarType ratio_media=0.f;
while(!posl.LoopEnd())
{
ratio_media+=posl.T()->AspectRatio();
posl.NextT();
num++;
}
ratio_media=ratio_media/num;
return (ratio_media);
}
///Modify pos and alfa to obtain the collapse that minimize the error
ScalarType _VolumePreservingError(PosType &pos,CoordType &new_point,int nsteps)
{
VertexType *ve0=(pos.T()->V(Tetra::VofE(pos.E(),0)));
VertexType *ve1=(pos.T()->V(Tetra::VofE(pos.E(),1)));
bool ext_v0=ve0->IsB();
bool ext_v1=ve1->IsB();
ScalarType best_error=0.f;
if ((ext_v0)&&(!ext_v1))
new_point=ve0->P();
else
if ((!ext_v0)&&(ext_v1))
new_point=ve1->P();
else
if ((!ext_v0)&&(!ext_v1))
{/*CoordType g;
g.SetZero();
g+=ve0->cP();
g+=ve1->cP();
g/=2;*/
new_point=(ve0->cP()+ve1->cP())/2.f;
}
else
if ((ext_v0)&&(ext_v1))//both are external vertex
{
ScalarType step=1.f/(nsteps-1);
ScalarType Vol_Original=_EC.VolumeOriginal();
for (int i=0;i<nsteps;i++)
{
best_error=1000000.f;
ScalarType alfatemp=step*((ScalarType)i);
//CoordType g;
// g.SetZero();
//g+=ve0->cP()*alfatemp;
//g+=ve1->cP()*(1-alfatemp);
//CoordType newPTemp=g;
CoordType newPTemp=(ve0->cP()*alfatemp) +(ve1->cP()*(1.f-alfatemp));
//the error is the absolute value of difference of volumes
ScalarType error=fabs(Vol_Original-_EC.VolumeSimulateCollapse(pos,newPTemp));
if(error<best_error)
{
new_point=newPTemp;
best_error=error;
}
}
}
return (best_error);
}
public:
virtual const char *Info(TETRA_MESH_TYPE &m) {
static char buf[60];
//sprintf(buf,"collapse %i -> %i %f\n", pos.()-&m.vert[0], pos.VFlip()-&m.vert[0],_priority);
return buf;
}
ScalarType ComputePriority()
{
return (_priority = _AspectRatioMedia(this->pos));
}
ScalarType ComputeError()
{
vrem=(pos.T()->V(Tetra::VofE(pos.E(),0)));
return (_VolumePreservingError(pos,_NewPoint,5));// magic number....parametrize!
}
void Execute(TETRA_MESH_TYPE &tm)
{
// _EC.FindSets(pos);
assert(!vrem->IsD());
int del=_EC.DoCollapse(pos,_NewPoint);
tm.tn-=del;
tm.vn-=1;
}
void UpdateHeap(typename LocalOptimization<TETRA_MESH_TYPE>::HeapType & h_ret)
{
assert(!vrem->IsD());
_Imark()++;
VTIterator<TetraType> VTi(vrem->VTb(),vrem->VTi());
while (!VTi.End())
{
VTi.Vt()->ComputeVolume();
for (int j=0;j<6;j++)
{
vcg::tetra::Pos<TetraType> p=Pos<TetraType>(VTi.Vt(),Tetra::FofE(j,0),j,Tetra::VofE(j,0));
assert(!p.T()->V(p.V())->IsD());
assert(!p.T()->IsD());
h_ret.push_back(HeapElem(new TetraEdgeCollapse<TETRA_MESH_TYPE>(p,_Imark())));
std::push_heap(h_ret.begin(),h_ret.end());
// update the mark of the vertices
VTi.Vt()->V(Tetra::VofE(j,0))->IMark() = _Imark();
}
++VTi;
}
}
/// return the type of operation
ModifierType IsOfType(){ return TetraEdgeCollapseOp;}
bool IsFeasible(){
vcg::tetra::EdgeCollapse<TETRA_MESH_TYPE>::Reset();
_EC.FindSets(pos);
ComputeError();
return(_EC.CheckPreconditions(pos,_NewPoint));
}
bool IsUpToDate(){
if (!pos.T()->IsD())
{
VertexType *v0=pos.T()->V(Tetra::VofE(pos.E(),0));
VertexType *v1=pos.T()->V(Tetra::VofE(pos.E(),1));
assert(!v0->IsD());
assert(!v1->IsD());
if(! (( (!v0->IsD()) && (!v1->IsD())) &&
_Imark()>=v0->IMark() &&
_Imark()>=v1->IMark()))
{
FAIL::OFD();
return false;
}
else
return true;
}
else
return false;
}
virtual ScalarType Priority() const {
return _priority;
}
/// perform initialization
static void Init(TETRA_MESH_TYPE &m,typename LocalOptimization<TETRA_MESH_TYPE>::HeapType& h_ret){
h_ret.clear();
typename TETRA_MESH_TYPE::TetraIterator ti;
for(ti = m.tetra.begin(); ti != m.tetra.end();++ti)
if(!(*ti).IsD()){
(*ti).ComputeVolume();
for (int j=0;j<6;j++)
{
PosType p=PosType(&*ti,Tetra::FofE(j,0),j,Tetra::VofE(j,0));
assert(!p.T()->V(p.V())->IsD());
assert(!p.T()->IsD());
h_ret.push_back(HeapElem(new TetraEdgeCollapse<TETRA_MESH_TYPE>(p,m.IMark)));
}
}
}
};
}//end namespace tetra
}//end namespace vcg
#endif