vcglib/vcg/complex/local_optimization/tri_edge_flip.h

610 lines
15 KiB
C++

/****************************************************************************
* 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. *
* *
****************************************************************************/
#ifndef __VCG_DECIMATION_TRIFLIP
#define __VCG_DECIMATION_TRIFLIP
#include <vcg/complex/local_optimization.h>
#include <vcg/simplex/face/topology.h>
#include <vcg/space/triangle3.h>
namespace vcg
{
namespace tri
{
/** \addtogroup trimesh */
/* @{ */
/*!
* This Class is specialization of LocalModification for the edge flip
* It wraps the atomic operation EdgeFlip to be used in a optimization routine.
* Note that it has knowledge of the heap of the class LocalOptimization because
* it is responsible of updating it after a flip has been performed
* This is the simplest edge flipping class.
* It flips an edge only if two adjacent faces are coplanar and the
* quality of the faces improves after the flip.
*/
template <class TRIMESH_TYPE, class MYTYPE,
typename TRIMESH_TYPE::ScalarType (*QualityFunc)(
Point3<typename TRIMESH_TYPE::ScalarType> const & p0,
Point3<typename TRIMESH_TYPE::ScalarType> const & p1,
Point3<typename TRIMESH_TYPE::ScalarType> const & p2) = Quality>
class PlanarEdgeFlip :
public LocalOptimization< TRIMESH_TYPE>::LocModType
{
protected:
typedef typename TRIMESH_TYPE::FaceType FaceType;
typedef typename TRIMESH_TYPE::FacePointer FacePointer;
typedef typename TRIMESH_TYPE::FaceIterator FaceIterator;
typedef typename TRIMESH_TYPE::VertexType VertexType;
typedef typename TRIMESH_TYPE::ScalarType ScalarType;
typedef typename TRIMESH_TYPE::VertexPointer VertexPointer;
typedef typename TRIMESH_TYPE::CoordType CoordType;
typedef vcg::face::Pos<FaceType> PosType;
typedef typename LocalOptimization<TRIMESH_TYPE>::HeapElem HeapElem;
typedef typename LocalOptimization<TRIMESH_TYPE>::HeapType HeapType;
/*!
* the pos of the flipping
*/
PosType _pos;
/*!
* priority in the heap
*/
ScalarType _priority;
/*!
* Mark for updating
*/
int _localMark;
/*!
* mark for up_dating
*/
static int& GlobalMark()
{
static int im = 0;
return im;
}
static void Insert(HeapType& heap, PosType& p, int mark)
{
if(!p.IsBorder() && p.F()->IsW() && p.FFlip()->IsW()) {
MYTYPE* newflip = new MYTYPE(p, mark);
heap.push_back(HeapElem(newflip));
std::push_heap(heap.begin(), heap.end());
}
}
public:
/*!
* Default constructor
*/
inline PlanarEdgeFlip()
{
}
/*!
* Constructor with <I>pos</I> type
*/
inline PlanarEdgeFlip(PosType pos, int mark)
{
_pos = pos;
_localMark = mark;
_priority = this->ComputePriority();
}
/*!
* Copy Constructor
*/
inline PlanarEdgeFlip(const PlanarEdgeFlip &par)
{
_pos = par.GetPos();
_localMark = par.GetMark();
_priority = par.Priority();
}
/*!
*/
~PlanarEdgeFlip()
{
}
/*!
* Parameter
*/
static ScalarType &CoplanarAngleThresholdDeg()
{
static ScalarType _CoplanarAngleThresholdDeg = 0.01f;
return _CoplanarAngleThresholdDeg;
}
inline PosType GetPos() const
{
return _pos;
}
inline int GetMark()const
{
return _localMark;
}
/*!
* Return the LocalOptimization type
*/
ModifierType IsOfType()
{
return TriEdgeFlipOp;
}
/*!
* Check if the pos is updated
*/
bool IsUpToDate()
{
int lastMark = _pos.F()->V(0)->IMark();
lastMark = std::max<int>(lastMark, _pos.F()->V(1)->IMark());
lastMark = std::max<int>(lastMark, _pos.F()->V(2)->IMark());
return ( _localMark >= lastMark );
}
/*!
*
Check if this flipping operation can be performed.
It is a topological and geometrical check.
*/
virtual bool IsFeasible()
{
if(!vcg::face::CheckFlipEdge(*this->_pos.F(), this->_pos.E()))
return false;
if( math::ToDeg( Angle(_pos.FFlip()->cN(), _pos.F()->cN()) ) > CoplanarAngleThresholdDeg() )
return false;
CoordType v0, v1, v2, v3;
int i = _pos.E();
v0 = _pos.F()->P0(i);
v1 = _pos.F()->P1(i);
v2 = _pos.F()->P2(i);
v3 = _pos.F()->FFp(i)->P2(_pos.F()->FFi(i));
// Take the parallelogram formed by the adjacent faces of edge
// If a corner of the parallelogram on extreme of edge to flip is >= 180
// the flip produce two identical faces - avoid this
if( (Angle(v2 - v0, v1 - v0) + Angle(v3 - v0, v1 - v0) >= M_PI) ||
(Angle(v2 - v1, v0 - v1) + Angle(v3 - v1, v0 - v1) >= M_PI))
return false;
// if any of two faces adj to edge in non writable, the flip is unfeasible
if(!_pos.F()->IsW() || !_pos.F()->FFp(i)->IsW())
return false;
return true;
}
/*!
* Compute the priority of this optimization
*/
/*
1
/|\
/ | \
2 | 3
\ | /
\|/
0
*/
ScalarType ComputePriority()
{
CoordType v0, v1, v2, v3;
int i = _pos.E();
v0 = _pos.F()->P0(i);
v1 = _pos.F()->P1(i);
v2 = _pos.F()->P2(i);
v3 = _pos.F()->FFp(i)->P2(_pos.F()->FFi(i));
ScalarType Qa = QualityFunc(v0, v1, v2);
ScalarType Qb = QualityFunc(v0, v3, v1);
ScalarType QaAfter = QualityFunc(v1, v2, v3);
ScalarType QbAfter = QualityFunc(v0, v3, v2);
// < 0 if the average quality of faces improves after flip
_priority = (Qa + Qb - QaAfter - QbAfter) / (ScalarType)2.0;
return _priority;
}
/*!
* Return the priority of this optimization
*/
virtual ScalarType Priority() const
{
return _priority;
}
/*!
* Execute the flipping of the edge
*/
void Execute(TRIMESH_TYPE &m)
{
int i = _pos.E();
int j = _pos.F()->FFi(i);
FacePointer f1 = _pos.F();
FacePointer f2 = _pos.F()->FFp(i);
vcg::face::FlipEdge(*_pos.F(), _pos.E());
// avoid texture coordinates swap after flip
if(tri::HasPerWedgeTexCoord(m)) {
f2->WT((j + 1) % 3) = f1->WT((i + 2) % 3);
f1->WT((i + 1) % 3) = f2->WT((j + 2) % 3);
}
}
/*!
*/
const char* Info(TRIMESH_TYPE &m)
{
static char dump[60];
sprintf(dump,"%d -> %d %g\n", _pos.F()->V(0)-&m.vert[0], _pos.F()->V(1)-&m.vert[0],-_priority);
return dump;
}
/*!
*/
static void Init(TRIMESH_TYPE &mesh, HeapType &heap)
{
heap.clear();
FaceIterator fi;
for(fi = mesh.face.begin(); fi != mesh.face.end(); ++fi) {
if(!(*fi).IsD() && (*fi).IsW()) {
for(unsigned int i = 0; i < 3; i++) {
if( !(*fi).IsB(i) && !((*fi).FFp(i)->IsD()) && (*fi).FFp(i)->IsW() ) {
if((*fi).V1(i) - (*fi).V0(i) > 0) {
PosType p(&*fi, i);
Insert(heap, p, IMark(mesh));
}
//heap.push_back( HeapElem( new MYTYPE(PosType(&*fi, i), mesh.IMark() )) );
} //endif
} //endfor
}
} //endfor
}
/*!
*/
virtual void UpdateHeap(HeapType &heap)
{
GlobalMark()++;
// after flip, the new edge just created is the next edge
int flipped = (_pos.E() + 1) % 3;
PosType pos(_pos.F(), flipped);
pos.F()->V(0)->IMark() = GlobalMark();
pos.F()->V(1)->IMark() = GlobalMark();
pos.F()->V(2)->IMark() = GlobalMark();
pos.F()->FFp(flipped)->V2(pos.F()->FFi(flipped))->IMark() = GlobalMark();
pos.FlipF(); pos.FlipE();
Insert(heap, pos, GlobalMark());
pos.FlipV(); pos.FlipE();
Insert(heap, pos, GlobalMark());
pos.FlipV(); pos.FlipE();
pos.FlipF(); pos.FlipE();
Insert(heap, pos, GlobalMark());
pos.FlipV(); pos.FlipE();
Insert(heap, pos, GlobalMark());
}
}; // end of PlanarEdgeFlip class
template <class TRIMESH_TYPE, class MYTYPE>
class TriEdgeFlip : public PlanarEdgeFlip<TRIMESH_TYPE, MYTYPE>
{
protected:
typedef typename TRIMESH_TYPE::FaceType FaceType;
typedef typename TRIMESH_TYPE::ScalarType ScalarType;
typedef typename TRIMESH_TYPE::CoordType CoordType;
typedef vcg::face::Pos<FaceType> PosType;
public:
/*!
* Default constructor
*/
inline TriEdgeFlip() {}
/*!
* Constructor with <I>pos</I> type
*/
inline TriEdgeFlip(const PosType pos, int mark)
{
this->_pos = pos;
this->_localMark = mark;
this->_priority = ComputePriority();
}
/*!
* Copy Constructor
*/
inline TriEdgeFlip(const TriEdgeFlip &par)
{
this->_pos = par.GetPos();
this->_localMark = par.GetMark();
this->_priority = par.Priority();
}
ScalarType ComputePriority()
{
/*
1
/|\
/ | \
2 | 3
\ | /
\|/
0
*/
CoordType v0, v1, v2, v3;
int i = this->_pos.E();
v0 = this->_pos.F()->P0(i);
v1 = this->_pos.F()->P1(i);
v2 = this->_pos.F()->P2(i);
v3 = this->_pos.F()->FFp(i)->P2(this->_pos.F()->FFi(i));
// if the sum of angles in v2 e v3 is > 180, then the triangle
// pair is not a delaunay triangulation
ScalarType alpha = math::Abs(Angle(v0 - v2, v1 - v2));
ScalarType beta = math::Abs(Angle(v0 - v3, v1 - v3));
this->_priority = 180 - math::ToDeg((alpha + beta));
return this->_priority;
}
};
// This kind of flip minimize the variance of number of incident faces
// on the vertices of two faces involved in the flip
template <class TRIMESH_TYPE, class MYTYPE>
class TopoEdgeFlip : public PlanarEdgeFlip<TRIMESH_TYPE, MYTYPE>
{
protected:
typedef typename TRIMESH_TYPE::VertexPointer VertexPointer;
typedef typename TRIMESH_TYPE::FaceType FaceType;
typedef typename TRIMESH_TYPE::FacePointer FacePointer;
typedef typename TRIMESH_TYPE::ScalarType ScalarType;
typedef typename TRIMESH_TYPE::CoordType CoordType;
typedef vcg::face::Pos<FaceType> PosType;
typedef typename LocalOptimization<TRIMESH_TYPE>::HeapElem HeapElem;
typedef typename LocalOptimization<TRIMESH_TYPE>::HeapType HeapType;
typedef typename TRIMESH_TYPE::FaceIterator FaceIterator;
typedef typename TRIMESH_TYPE::VertexIterator VertexIterator;
public:
/*!
* Default constructor
*/
inline TopoEdgeFlip() {}
/*!
* Constructor with <I>pos</I> type
*/
inline TopoEdgeFlip(const PosType pos, int mark)
{
this->_pos = pos;
this->_localMark = mark;
this->_priority = ComputePriority();
}
/*!
* Copy Constructor
*/
inline TopoEdgeFlip(const TopoEdgeFlip &par)
{
this->_pos = par.GetPos();
this->_localMark = par.GetMark();
this->_priority = par.Priority();
}
ScalarType ComputePriority()
{
/*
1
/|\
/ | \
2 | 3
\ | /
\|/
0
*/
VertexPointer v0, v1, v2, v3;
int i = this->_pos.E();
v0 = this->_pos.F()->V0(i);
v1 = this->_pos.F()->V1(i);
v2 = this->_pos.F()->V2(i);
v3 = this->_pos.F()->FFp(i)->V2(this->_pos.F()->FFi(i));
// This kind of flip minimize the variance of number of incident faces
// on the vertices of two faces involved in the flip
ScalarType avg = (v0->Q() + v1->Q() + v2->Q() + v3->Q()) / 4.0;
ScalarType varbefore = (powf(v0->Q() - avg, 2.0) +
powf(v1->Q() - avg, 2.0) +
powf(v2->Q() - avg, 2.0) +
powf(v3->Q() - avg, 2.0)) / 4.0;
ScalarType varafter = (powf(v0->Q() - 1 - avg, 2.0) +
powf(v1->Q() - 1 - avg, 2.0) +
powf(v2->Q() + 1 - avg, 2.0) +
powf(v3->Q() + 1 - avg, 2.0)) / 4.0;
this->_priority = varafter - varbefore;
return this->_priority;
}
/*!
* Execute the flipping of the edge
*/
void Execute(TRIMESH_TYPE &m)
{
int i = this->_pos.E();
FacePointer f1 = this->_pos.F();
FacePointer f2 = f1->FFp(i);
int j = f1->FFi(i);
// update the number of faces adjacent to vertices
f1->V0(i)->Q()--;
f1->V1(i)->Q()--;
f1->V2(i)->Q()++;
f2->V2(j)->Q()++;
// do the flip
vcg::face::FlipEdge(*this->_pos.F(), this->_pos.E());
// avoid texture coordinates swap after flip
if (tri::HasPerWedgeTexCoord(m)) {
f2->WT((j + 1) % 3) = f1->WT((i + 2) % 3);
f1->WT((i + 1) % 3) = f2->WT((j + 2) % 3);
}
}
static void Init(TRIMESH_TYPE &m, HeapType &heap)
{
// reset quality field for each vertex
VertexIterator vi;
for(vi = m.vert.begin(); vi != m.vert.end(); ++vi)
if(!(*vi).IsD())
(*vi).Q() = 0;
// for each vertex, put the number of incident faces in quality field
FaceIterator fi;
for(fi = m.face.begin(); fi != m.face.end(); ++fi)
if(!(*fi).IsD())
for(int i = 0; i < 3; i++)
(*fi).V(i)->Q()++;
TriEdgeFlip<TRIMESH_TYPE, MYTYPE>::Init(m, heap);
}
void UpdateHeap(HeapType &heap)
{
this->GlobalMark()++;
VertexPointer v0, v1, v2, v3;
int flipped = (this->_pos.E() + 1) % 3;
FacePointer f1 = this->_pos.F();
FacePointer f2 = this->_pos.F()->FFp(flipped);
v0 = f1->V0(flipped);
v1 = f1->V1(flipped);
v2 = f1->V2(flipped);
v3 = f2->V2(f1->FFi(flipped));
v0->IMark() = this->GlobalMark();
v1->IMark() = this->GlobalMark();
v2->IMark() = this->GlobalMark();
v3->IMark() = this->GlobalMark();
// edges of the first face, except the flipped edge
for(int i = 0; i < 3; i++) if(i != flipped) {
PosType newpos(f1, i);
Insert(heap, newpos, this->GlobalMark());
}
// edges of the second face, except the flipped edge
for(int i = 0; i < 3; i++) if(i != f1->FFi(flipped)) {
PosType newpos(f2, i);
Insert(heap, newpos, this->GlobalMark());
}
// every edge with v0, v1 v3 of f1
for(int i = 0; i < 3; i++) {
PosType startpos(f1, i);
PosType pos(startpos);
do { // go to the first border (if there is one)
pos.NextE();
} while(pos != startpos && !pos.IsBorder());
// if a border is reached, set startpos here
if(pos.IsBorder())
startpos = pos;
do {
VertexPointer v = pos.VFlip();
if(v != v0 && v != v1 && v != v2 && v != v3)
Insert(heap, pos, this->GlobalMark());
pos.NextE();
} while(pos != startpos && !pos.IsBorder());
}
PosType startpos(f2, (f1->FFi(flipped) + 2) % 3);
PosType pos(startpos);
do { // go to the first border (if there is one)
pos.NextE();
} while(pos != startpos && !pos.IsBorder());
// if a border is reached, set startpos here
if(pos.IsBorder())
startpos = pos;
do {
VertexPointer v = pos.VFlip();
if(v != v0 && v != v1 && v != v2 && v != v3)
Insert(heap, pos, this->GlobalMark());
pos.NextE();
} while(pos != startpos && !pos.IsBorder());
}
};
} // end of namespace tri
} // end of namespace vcg
#endif