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/****************************************************************************
* VCGLib o o *
* Visual and Computer Graphics Library o o *
* _ O _ *
* Copyright(C) 2004-2016 \/)\/ *
* 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_EDGE_TOPOLOGY
#define _VCG_EDGE_TOPOLOGY
namespace vcg {
namespace edge {
/** \addtogroup edge */
/*@{*/
template <class EdgeType>
inline bool IsEdgeManifold( EdgeType const & e, const int j )
{
return ( e.cEEp(j) == &e || &e == e.cEEp(j)->cEEp(e.cEEi(j)) );
}
/** Return a boolean that indicate if the j-th edge of the face is a border.
@param j Index of the edge
@return true if j is an edge of border, false otherwise
*/
template <class EdgeType>
inline bool IsEdgeBorder(EdgeType const & e, const int j )
{
if(EdgeType::HasEEAdjacency())
return e.cEEp(j)==&e;
assert(0);
return true;
}
template <class VertexType>
void VVStarVE(const VertexType* vp, std::vector<VertexType *> &starVec)
{
starVec.clear();
edge::VEIterator<typename VertexType::EdgeType> vei(vp);
while(!vei.End())
{
starVec.push_back(vei.V1());
++vei;
}
}
template <class EdgeType>
void VEStarVE(const typename EdgeType::VertexType* vp, std::vector<EdgeType *> &starVec)
{
starVec.clear();
edge::VEIterator<EdgeType> vei(vp);
while(!vei.End())
{
starVec.push_back(vei.E());
++vei;
}
}
/// Completely detach an edge from the VE adjacency. Useful before deleting it
template <class EdgeType>
void VEDetach(EdgeType & e)
{
VEDetach(e,0);
VEDetach(e,1);
}
/// It detaches the given edge e from the VE adjacency on the vertex z
/// It is used for careful hand stictching of topologies.
template <class EdgeType>
void VEDetach(EdgeType & e, int z)
{
typename EdgeType::VertexType *vz = e.V(z); // the vertex from which the edge must be detached.
if(vz->VEp()==&e ) //if it is the first edge in the VE chain it detaches it from the begin
{
assert(vz->VEi() == z);
vz->VEp() = e.VEp(z);
vz->VEi() = e.VEi(z);
return;
}
else // scan the list of edges to find the current edge e to be detached
{
for( VEIterator<EdgeType> vei(vz);!vei.End();++vei)
{
if(vei.E()->VEp(vei.I()) == &e)
{
vei.e->VEp(vei.z) = e.VEp(z);
vei.e->VEi(vei.z) = e.VEi(z);
return;
}
}
assert(0);
}
}
/// Append an edge in the VE list of vertex e->V(z)
template <class EdgeType>
void VEAppend(EdgeType* e, int z)
{
typename EdgeType::VertexType *v = e->V(z);
if (v->VEp()!=0)
{
EdgeType *e0=v->VEp();
int z0=v->VEi();
//append
e->VEp(z)=e0;
e->VEi(z)=z0;
}
else
{
e->VEp(z)=0;
e->VEi(z)=-1;
}
v->VEp()=e;
v->VEi()=z;
}
/*! Perform a simple edge collapse using VE adjacency
*
* It collapses the two edges incidnent on the indicated vertex so that the passed edge survives,
* the indicated vertex is deleted, and the edge ajacent to e0 along z is deleted too.
* It assumes that the edge mesh is 1-Manifold.
* If the indicated vertex <vd> is boundary or non manifold the function do nothing.
*
* v0 vd v1
* ---O-------O-------O---
* z0 e0 z e1 z1
*
* v0 v1
* ---O---------------O---
* e0
*
*
*/
template <class MeshType>
void VEEdgeCollapse(MeshType &poly, typename MeshType::EdgeType *e0, const int z)
{
typedef typename MeshType::EdgeType EdgeType;
typedef typename MeshType::VertexType VertexType;
VertexType *vd = e0->V(z);
std::vector<EdgeType *> starVecEp;
edge::VEStarVE(vd,starVecEp);
if(starVecEp.size()!=2) return;
EdgeType *e1=0; // this edge will be deleted
if( starVecEp[0] == e0 ) e1 = starVecEp[1];
if( starVecEp[1] == e0 ) e1 = starVecEp[0];
assert(e1 && (e1!=e0) );
//int z0 = (z+1)%2;
int z1 = -1;
if(e1->V(0) == vd) z1=1;
if(e1->V(1) == vd) z1=0;
assert(z1!=-1);
VertexType *v1 = e1->V(z1);
assert(v1 != vd);
edge::VEDetach(*e1); // detach the edge to be deleted.
edge::VEDetach(*e0,z); // detach one side of the surviving edge
e0->V(z) = v1; // change one extreme of the edge
edge::VEAppend(e0, z); // attach it again.
tri::Allocator<MeshType>::DeleteEdge(poly,*e1);
tri::Allocator<MeshType>::DeleteVertex(poly,*vd);
}
template <class MeshType>
void VEEdgeCollapse(MeshType &poly, typename MeshType::VertexType *v)
{
VEEdgeCollapse(poly,v->VEp(),v->VEi());
}
/*! Perform a simple edge split using VE adjacency
*
*/
template <class MeshType>
void VEEdgeSplit(MeshType &poly, typename MeshType::EdgeType *e, typename MeshType::VertexType &v)
{
typename MeshType::VertexPointer v1 = e->V(1);
edge::VEDetach(*e,1);
e->V(1) = &v;
edge::VEAppend(e,1);
typename tri::Allocator<MeshType>::template PointerUpdater<typename MeshType::EdgePointer> pu;
typename MeshType::EdgeIterator ei = tri::Allocator<MeshType>::AddEdges(poly, 1, pu);
pu.Update(e);
ei->ImportData(*e);
ei->V(0)=&v;
ei->V(1)=v1;
edge::VEAppend(&*ei,0);
edge::VEAppend(&*ei,1);
}
template <class MeshType>
typename MeshType::VertexPointer VEEdgeSplit(MeshType &poly, typename MeshType::EdgeType *e, const typename MeshType::CoordType &p)
{
typename MeshType::VertexIterator vi = tri::Allocator<MeshType>::AddVertex(poly,p);
VEEdgeSplit(poly,e,*vi);
return &*vi;
}
template <class MeshType>
typename MeshType::VertexPointer VEEdgeSplit(MeshType &poly, typename MeshType::EdgeType *e, const typename MeshType::CoordType &p, const typename MeshType::CoordType &n)
{
typename MeshType::VertexIterator vi = tri::Allocator<MeshType>::AddVertex(poly,p,n);
VEEdgeSplit(poly,e,*vi);
return &*vi;
}
/*! Returns the number of incident edges over a vertex vp; Using the VE adjacency.
*
* It just follows the chain of incident edges of the VE adjacency.
*/
template <class EdgeType>
int VEDegree(const typename EdgeType::VertexType* vp)
{
int cnt=0;
edge::VEIterator<EdgeType> vei(vp);
while(!vei.End())
{
++cnt;
++vei;
}
return cnt;
}
} // end namespace edge
} // end namespace vcg
#endif
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