[introduction of half edges as alternative representation]
No modification should be necessary for the existing code. most relevant changes: creation of folder: vcg/connectors vcg/connectors/hedge.h vcg/connectors/hedge_component.h addition to the container of half edges to the trimesh: HEdgeContainer hedge; // container int hn; // number of half edges addition of vcg/trimesh/update/halfedge_indexed.h which contains: - the functions to compute the half edge representation from the indexed and vivecersa - the functions to add or remove an half edge
This commit is contained in:
ganovelli
parent
261ff53ab1
commit
d4b7e1c8fe
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/****************************************************************************
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* VCGLib o o *
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* Visual and Computer Graphics Library o o *
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* _ O _ *
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* Copyright(C) 2004 \/)\/ *
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* Visual Computing Lab /\/| *
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* ISTI - Italian National Research Council | *
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* \ *
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* All rights reserved. *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
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* for more details. *
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* *
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****************************************************************************/
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#ifndef __VCGLIB_EDGE_SUPPORT
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#define __VCGLIB_EDGE_SUPPORT
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#include <vector>
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#include <vcg/complex/trimesh/allocate.h>
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#include <vcg/complex/trimesh/clean.h>
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#include <vcg/complex/trimesh/update/topology.h>
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#include <vcg/complex/trimesh/base.h>
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namespace vcg
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{
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namespace tri{
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/// \ingroup trimesh
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/// \headerfile edge_support.h vcg/complex/trimesh/edge_support.h
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/// \brief This class is used to build edge based data structure from indexed data structure and viceversa
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/**
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*/
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template <class MeshType >
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class HEdgeSupport{
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public:
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typedef typename MeshType::VertexType VertexType;
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typedef typename MeshType::VertexPointer VertexPointer;
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typedef typename MeshType::HEdgePointer HEdgePointer;
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typedef typename MeshType::HEdgeType HEdgeType;
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typedef typename MeshType::HEdgeIterator HEdgeIterator;
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typedef typename MeshType::FaceIterator FaceIterator;
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typedef typename MeshType::FaceType FaceType;
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struct VertexPairEdgePtr{
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VertexPairEdgePtr(VertexPointer _v0,VertexPointer _v1,HEdgePointer _ep):v0(_v0),v1(_v1),ep(_ep){if(v0>v1) std::swap(v0,v1);}
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const bool operator <(const VertexPairEdgePtr &o) const {return (v0 == o.v0)? (v1<o.v1):(v0<o.v0);}
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const bool operator ==(const VertexPairEdgePtr &o) const {return (v0 == o.v0)&& (v1==o.v1);}
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VertexPointer v0,v1;
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HEdgePointer ep;
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};
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struct FacePtrInt{
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FacePtrInt ( FaceType * _f,int _i):f(_f),i(_i){}
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FaceType * f;
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int i;
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};
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typedef std::vector<bool> BitVector;
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/**
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build a half-edge data structure from an indexed data structure. Note that the half-edges are allocated here for the first time.
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If you have a mesh where there are already edges, they will be removed and the data lost, so do not use this function
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to just "update" the topology of half edges.
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**/
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static void ComputeHalfEdgeFromIndexed(MeshType & m){
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assert(HasFVAdjacency(m));
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assert(HasHOppAdjacency(m));
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assert(HasHNextAdjacency(m));
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typename MeshType::template PerFaceAttributeHandle<BitVector> flagVisited =
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vcg::tri::Allocator<MeshType>::template AddPerFaceAttribute<BitVector>(m,"");
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std::vector<FacePtrInt > borderEdges;
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// allocate all new half edges
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FaceIterator fi;
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int n_edges = 0;
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// count how many half edge to allocate
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for(fi = m.face.begin(); fi != m.face.end(); ++fi) if(! (*fi).IsD())
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{n_edges+=(*fi).VN();
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for(int i = 0; i < (*fi).VN(); ++i)
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if(vcg::face::IsBorder<FaceType>((*fi),(i)))
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++n_edges;
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}
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// allocate the half edges
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typename MeshType::HEdgeIterator ei = vcg::tri::Allocator<MeshType>::AddHEdges(m,n_edges);
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std::vector<VertexPairEdgePtr> all;
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int firstEdge = 0;
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for(fi = m.face.begin(); fi != m.face.end(); ++fi)if(!(*fi).IsD()){
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assert((*fi).VN()>2);
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if(flagVisited[*fi].empty()) {flagVisited[*fi].resize((*fi).VN());}
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for(int i = 0; i < (*fi).VN(); ++i,++ei)
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{
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(*ei).HVp() = (*fi).V(i);
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(*ei).HNp() = &m.hedge[firstEdge + (i +1) % (*fi).VN()];
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if(MeshType::HEdgeType::HasHFAdjacency())
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(*ei).HFp() = &(*fi);
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if( MeshType::FaceType::HasFHAdjacency())
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(*fi).FHp() = &(*ei);
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if(MeshType::HEdgeType::HasHPrevAdjacency())
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(*ei).HPp() = &m.hedge[firstEdge + (i +(*fi).VN()-1) % (*fi).VN()];
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if(HasVHAdjacency(m))
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(*ei).HVp()->VHp() = &(*ei);
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all.push_back(VertexPairEdgePtr((*fi).V(i), (*fi).V((*fi).Next(i)),&(*ei)));// it will be used to link the hedges
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if( vcg::face::IsBorder<FaceType>((*fi),(i)))
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borderEdges.push_back(FacePtrInt(&(*fi),i));
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}
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firstEdge += (*fi).VN();
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}
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// add all the border edges
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int borderLength;
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typename std::vector<FacePtrInt >::iterator ebi;
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for( ebi = borderEdges.begin(); ebi != borderEdges.end(); ++ebi)
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if( !flagVisited[(*ebi).f][(*ebi).i])// not already inserted
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{
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borderLength = 0;
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vcg::face::Pos<FaceType> bp((*ebi).f,(*ebi).i);
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FaceType * start = (*ebi).f;
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do{
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all.push_back( VertexPairEdgePtr ( bp.f->V( bp.f->Next(bp.z) ),bp.f->V( bp.z ),&(*ei)));
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(*ei).HVp() = bp.f->V(bp.f->Next(bp.z)) ;
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flagVisited[bp.f][bp.z] = true;
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++ei;
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bp.NextB();
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++borderLength;
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}while (bp.f != start);
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// run over the border edges to link the adjacencies
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for(int be = 0; be < borderLength; ++be){
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if(MeshType::HEdgeType::HasHFAdjacency())
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m.hedge[firstEdge + be].HFp() = NULL;
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if(MeshType::HEdgeType::HasHPrevAdjacency())
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m.hedge[firstEdge + be].HPp() = &m.hedge[firstEdge + (be +borderLength-1) % borderLength];
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m.hedge[firstEdge + be].HNp() = &m.hedge[firstEdge + (be +1) % borderLength];
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}
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firstEdge+=borderLength;
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}
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vcg::tri::Allocator<MeshType>:: template DeletePerFaceAttribute<BitVector>(m,flagVisited );
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std::sort(all.begin(),all.end());
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assert(all.size() == n_edges);
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for(int i = 0 ; i < all.size(); )
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if(all[i] == all[i+1])
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{
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all[i].ep->HOp() = all[i+1].ep;
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all[i+1].ep->HOp() = all[i].ep;
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i+=2;
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}
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else
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{
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all[i].ep->HOp() = all[i].ep;
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i+=1;
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}
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}
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/**
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builds an indexed data structure from a half-edge data structure.
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Note: if the half edge have the pointer to face
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their relation FV (face-vertex) will be computed and the data possibly stored in the
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face will be preserved.
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**/
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static void ComputeIndexedFromHalfEdge( MeshType & m ){
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assert(HasFVAdjacency(m));
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assert(MeshType::HEdgeType::HasHNextAdjacency());
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assert(MeshType::HEdgeType::HasHVAdjacency());
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assert(MeshType::HEdgeType::HasHOppAdjacency());
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assert(MeshType::FaceType::HasFHAdjacency());
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bool createFace,hasHEF,hasFHE;
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// typename MeshType::template PerHEdgeAttributeHandle<bool> hV = Allocator<MeshType>::template AddPerHEdgeAttribute<bool>(m,"");
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typename MeshType::HEdgeIterator ei;
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typename MeshType::FacePointer fp;
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typename MeshType::FaceIterator fi;
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typename MeshType::HEdgePointer ep,epF;
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int vi = 0;
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vcg::SimpleTempData<typename MeshType::HEdgeContainer,bool> hV(m.hedge);
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hasHEF = (MeshType::HEdgeType::HasHFAdjacency());
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assert( !hasHEF || (hasHEF && m.fn>0));
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// if the edgetype has the pointer to face
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// it is assumed the the edget2face pointer (HEFp) are correct
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// and the faces are allocated
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for ( ei = m.hedge.begin(); ei != m.hedge.end(); ++ei)
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if(!(*ei).IsD()) // it has not been deleted
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if(!hasHEF || ( hasHEF && (*ei).HFp()!=NULL)) // if it has a pointer to the face it is
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// not null (i.e. it is not a border edge)
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if(!hV[(*ei)] ) // it has not be visited yet
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{
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if(!hasHEF)// if it has
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fp = &(* Allocator<MeshType>::AddFaces(m,1));
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else
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fp = (*ei).HFp();
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ep = epF = &(*ei);
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std::vector<VertexPointer> vpts;
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do{vpts.push_back((*ep).HVp()); ep=ep->HNp();}while(ep!=epF);
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int idbg =fp->VN();
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if(fp->VN() != vpts.size()){
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fp->Dealloc();
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fp ->Alloc(vpts.size());
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}
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int idbg1 =fp->VN();
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for(unsigned int i = 0; i < vpts.size();++i) fp ->V(i) = vpts[i];// set the pointer from face to vertex
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hV[(*ei)] = true;
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}
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//Allocator<MeshType>::DeletePerHEdgeAttribute(m,hV);
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}
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/**
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Checks pointers FHEp() are valid
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**/
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static bool CheckConsistency_FHp(MeshType & m){
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assert(MeshType::FaceType::HasFHAdjacency());
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FaceIterator fi;
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for(fi = m.face.begin(); fi != m.face.end(); ++fi)
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if(!(*fi).IsD()){
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if((*fi).FHp() < &(*m.hedge.begin())) return false;
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if((*fi).FHp() > &(m.hedge.back())) return false;
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}
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return true;
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}
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/**
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Checks that half edges and face relation are consistent
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**/
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static bool CheckConsistency(MeshType & m){
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assert(MeshType::HEdgeType::HasHNextAdjacency());
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assert(MeshType::HEdgeType::HasHOppAdjacency());
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assert(MeshType::HEdgeType::HasHVAdjacency());
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assert(MeshType::FaceType::HasFHAdjacency());
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bool hasHEF = ( MeshType::HEdgeType::HasHFAdjacency());
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bool hasHEP = ( MeshType::HEdgeType::HasHPrevAdjacency());
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FaceIterator fi;
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HEdgePointer ep,ep1;
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int cnt = 0;
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if(( MeshType::HEdgeType::HasHFAdjacency())){
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int iDb = 0;
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for(fi = m.face.begin(); fi != m.face.end(); ++fi,++iDb)
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if(!(*fi).IsD())
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{
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ep = ep1 = (*fi).FHp();
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do{
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if(ep->IsD())
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return false; // the edge should not be connected, it has been deleted
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if(ep->HFp() != &(*fi))
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return false;// edge is not pointing to the rigth face
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ep = ep->HNp();
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if(cnt++ > m.hn)
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return false; // edges are ill connected (HENp())
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}while(ep!=ep1);
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}
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}
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HEdgePointer epPrev;
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HEdgeIterator ei;
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bool extEdge ;
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for( ei = m.hedge.begin(); ei != m.hedge.end(); ++ei)
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if(!(*ei).IsD())
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{
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cnt = 0;
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epPrev = ep = ep1 = &(*ei);
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do{
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extEdge = (ep->HFp()==NULL);
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if(hasHEP){
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if( ep->HNp()->HPp() != ep)
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return false; // next and prev relation are not mutual
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if( ep->HPp() == ep)
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return false; // the previous of an edge cannot be the edge itself
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}
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if( ep->HOp() == ep)
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return false; // opposite relation is not mutual
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if( ep->HOp()->HOp() != ep)
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return false; // opposite relation is not mutual
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if(ep->HNp() == ep)
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return false; // the next of an edge cannot be the edge itself
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ep = ep->HNp();
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if( ep->HVp() != epPrev->HOp()->HVp())
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return false; // the opposite edge points to a vertex different that the vertex of the next edge
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epPrev = ep;
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if(cnt++ > m.hn)
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return false; // edges are ill connected (HENp())
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}while(ep!=ep1);
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}
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return true;
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}
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/** Set the relations HFp(), FHp() from a loop of edges to a face
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*/
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private:
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static void SetRelationsLoopFace(HEdgeType * e0, FaceType * f){
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assert(HEdgeType::HasHNextAdjacency());
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assert(FaceType::HasFHAdjacency());
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HEdgeType *e = e0;
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assert(e!=NULL);
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do{ e->HFp() = f; e = e->HNp(); } while(e != e0);
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f->FHp() = e0;
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}
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/**
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Merge the two faces. This will probably become a class template or a functor
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*/
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static void MergeFaces(FaceType *, FaceType *){};
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/**
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Find previous hedge in the loop
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*/
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static HEdgeType * PreviousEdge(HEdgeType * e0){
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HEdgeType * ep = e0;
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do{
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if(ep->HNp() == e0) return ep;
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ep = ep->HNp();
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}while(ep!=e0);
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assert(0); // degenerate loop
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return 0;
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}
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public:
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/** Adds an edge between the sources of e0 and e1 and set all the topology relations.
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If the edges store the pointers to the faces then a new face is created.
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<--- e1 ---- X <------e1_HEPp---
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^
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||
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ei0 || ei1
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||
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v
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----e0_HEPp-> X ----- e0 ------>
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*/
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static void AddHEdge(MeshType &m, HEdgeType * e0, HEdgeType * e1){
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HEdgeType *iii =e0->HNp();
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assert(e1!=e0->HNp());
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assert(e0!=e1->HNp());
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HEdgePointer tmp;
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bool hasP = MeshType::HEdgeType::HasHPrevAdjacency();
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assert(e0->HOp() != e1); // the hedge already exists
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assert(e0!=e1->HNp());
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std::vector<typename MeshType::HEdgePointer* > toUpdate;
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toUpdate.push_back(&e0);
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toUpdate.push_back(&e1);
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HEdgeIterator ei0 = vcg::tri::Allocator<MeshType>::AddHEdges(m,2,toUpdate);
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HEdgeIterator ei1 = ei0; ++ei1;
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(*ei0).HNp() = e1;(*ei0).HVp() = e0->HVp();
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(*ei1).HNp() = e0;(*ei1).HVp() = e1->HVp();
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HEdgePointer e0_HEPp = 0,e1_HEPp = 0,ep =0;
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if(hasP){
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e0_HEPp = e0->HPp();
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e1_HEPp = e1->HPp();
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}else{// does not have pointer to previous, it must be computed
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ep = e0;
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do{
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if(ep->HNp() == e0) e0_HEPp = ep;
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if(ep->HNp() == e1) e1_HEPp = ep;
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ep = ep->HNp();
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}while(ep!=e0);
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}
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if(hasP){
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(*ei0).HPp() = e0->HPp();
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(*ei1).HPp() = e1->HPp();
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e0->HPp() = &(*ei1);
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e1->HPp() = &(*ei0);
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}
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e0_HEPp -> HNp() = &(*ei0);
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e1_HEPp -> HNp() = &(*ei1);
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(*ei0).HOp() = &(*ei1);
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(*ei1).HOp() = &(*ei0);
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if( HEdgeType::HasHFAdjacency() && FaceType::HasFHAdjacency()){
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FaceIterator fi0 = vcg::tri::Allocator<MeshType>::AddFaces(m,1);
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m.face.back().ImportLocal(*e0->HFp());
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SetRelationsLoopFace(&(*ei0),e1->HFp()); // one loop to the old face
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SetRelationsLoopFace(&(*ei1),&m.face.back()); // the other to the new face
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}
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}
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/** Detach the topology relations of a given edge
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<--- e->HENPp -X --- <---------eO_HEPp---
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^
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||
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e || e->HEOp()
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||
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v
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----e_HEPp--> X ----- e->HEOp->HENPp() ------>
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*/
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static void RemoveHEdge(MeshType &m, HEdgeType * e){
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assert(MeshType::HEdgeType::HasHNextAdjacency());
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assert(MeshType::HEdgeType::HasHOppAdjacency());
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assert(MeshType::FaceType::HasFHAdjacency());
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bool hasP = MeshType::HEdgeType::HasHPrevAdjacency();
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HEdgePointer e_HEPp,eO_HEPp;
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if(hasP){
|
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e_HEPp = e->HPp();
|
||||
eO_HEPp = e->HOp()->HPp();
|
||||
}else{
|
||||
e_HEPp = PreviousEdge(e);
|
||||
eO_HEPp = PreviousEdge(e->HOp());
|
||||
}
|
||||
|
||||
assert(e_HEPp->HNp() == e);
|
||||
assert(eO_HEPp->HNp() == e->HOp());
|
||||
e_HEPp->HNp() = e->HOp()->HNp();
|
||||
eO_HEPp->HNp() = e-> HNp();
|
||||
|
||||
if(hasP) {
|
||||
e->HOp()->HNp()->HPp() = e_HEPp;
|
||||
e->HNp()->HPp() = eO_HEPp;
|
||||
|
||||
e->HPp() = NULL;
|
||||
e-> HOp()->HPp() = NULL;
|
||||
}
|
||||
|
||||
|
||||
// take care of the faces
|
||||
if(MeshType::HEdgeType::HasHFAdjacency()){
|
||||
MergeFaces(e_HEPp->HFp(),eO_HEPp->HFp());
|
||||
vcg::tri::Allocator<MeshType>::DeleteFace(m,*eO_HEPp->HFp());
|
||||
SetRelationsLoopFace(e_HEPp,e_HEPp->HFp());
|
||||
|
||||
}
|
||||
vcg::tri::Allocator<MeshType>::DeleteHEdge(m,*e->HOp());
|
||||
vcg::tri::Allocator<MeshType>::DeleteHEdge(m,*e);
|
||||
|
||||
}
|
||||
|
||||
};// end class EdgeSupport
|
||||
} // end namespace vcg
|
||||
}
|
||||
#endif // __VCGLIB_EDGE_SUPPORT
|
||||
Loading…
Reference in New Issue