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Added correct code for Catmull Clark subdivision surfaces
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‎vcg/complex/algorithms/refine_catmullclark.h‎

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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) 2004-2024 \/)\/ *
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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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#pragma once
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namespace vcg {
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namespace tri {
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/// \ingroup trimesh
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/// \headerfile refine_doosabin.h vcg/complex/algorithms/refine_doosabin.h
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/// \brief This class is used convert between polygonal meshes and triangular meshes
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/**
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This class contains two members that allow to build a triangular mesh from a polygonal mesh
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and viceversa. In a trimesh, the generic polygons with n sides are codified represented by
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tagging the internal edge of the face as 'faux' with the SetF.
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*/
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template <class PolyMeshType>
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class CatmullClark {
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typedef typename PolyMeshType::FaceType FaceType;
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typedef typename PolyMeshType::FacePointer FacePointer;
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typedef typename PolyMeshType::FaceIterator FaceIterator;
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typedef typename PolyMeshType::VertexIterator VertexIterator;
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public:
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static void Refine(PolyMeshType &baseIn, PolyMeshType &refinedOut, int iterationNum=1)
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{
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PolyMeshType baseTmp,outTmp;
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tri::Append<PolyMeshType,PolyMeshType>::MeshCopy(baseTmp,baseIn);
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for(int i=0;i<iterationNum;++i)
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{
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RefineSingleStep(baseTmp, outTmp);
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tri::Append<PolyMeshType,PolyMeshType>::MeshCopy(baseTmp,outTmp);
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}
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tri::Append<PolyMeshType,PolyMeshType>::MeshCopy(refinedOut,outTmp);
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}
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static void RefineSingleStep(PolyMeshType &baseIn, PolyMeshType &refinedOut)
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{
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tri::RequirePolygonalMesh(baseIn);
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tri::RequirePolygonalMesh(refinedOut);
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refinedOut.Clear();
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//tri::RequireFFAdjacency(baseIn);
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// for the output mesh we keep a counter for each vertex as an additional attribute to computing averages easily
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auto v_cnH = tri::Allocator<PolyMeshType>::template AddPerVertexAttribute<int>(refinedOut,"counter");
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// for the input mesh we keep an attribute with the valence of the vertices
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auto v_valH = tri::Allocator<PolyMeshType>:: template AddPerVertexAttribute<int>(baseIn,"valence");
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// step -1 init the vertex valence counter to zero
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for(auto &v : baseIn.vert)
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v_valH[&v]=0;
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// Compute Valence for each vertex by iterating on all the faces
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for(auto &f : baseIn.face)
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for(int i=0;i<f.VN();i++)
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v_valH[f.V(i)]++;
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// step 0 copy all the vertexes in the output mesh
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for(auto &v : baseIn.vert)
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tri::Allocator<PolyMeshType>::AddVertex(refinedOut,Point3f(0,0,0));
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printf( "Mesh has %i vert and %i faces\n", refinedOut.VN(), refinedOut.FN() );
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// We keep two maps to store the new vertices created for the edges and the faces
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// and retrieve them when actually building the connectivity of the new mesh
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std::map<std::pair<int,int>, int> edgeMap;
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std::map<int, int> faceMap;
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// First Step Create the mid face vertices
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for(auto &f : baseIn.face)
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{
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auto vp = tri::Allocator<PolyMeshType>::AddVertex(refinedOut,PolyBarycenter(f));
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faceMap[tri::Index(baseIn,f)] = tri::Index(refinedOut,*vp);
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}
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// Second step. Create a vertex for each edge.
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// looping over all faces
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for(auto &f : baseIn.face)
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{
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Point3f center = refinedOut.vert[faceMap[tri::Index(baseIn,f)]].P();
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// loop over all edges
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for(int i=0;i<f.VN();i++)
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{
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int v0 = tri::Index(baseIn,f.V0(i));
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int v1 = tri::Index(baseIn,f.V1(i));
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if(v0>v1) std::swap(v0,v1);
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// check if the edge is already in the map
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auto it = edgeMap.find(std::make_pair(v0,v1));
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int edgeVertIndex;
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if(it == edgeMap.end())
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{
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// if not, create a new vertex in the middle of the edge
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auto vp = tri::Allocator<PolyMeshType>::AddVertex(refinedOut,Point3f(0,0,0));
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edgeMap[std::make_pair(v0,v1)] = tri::Index(refinedOut,*vp);
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edgeVertIndex = tri::Index(refinedOut,*vp);
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}
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else
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{
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edgeVertIndex = it->second;
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}
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refinedOut.vert[edgeVertIndex].P() += center*0.5;
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refinedOut.vert[edgeVertIndex].P() += f.V0(i)->P()*0.25;
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refinedOut.vert[edgeVertIndex].P() += f.V1(i)->P()*0.25;
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v_cnH[edgeVertIndex]+=1; // increment the counter of the vertex for the face
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}
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}
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// the only normalization step we do is for edge vertices to handle the fact
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// that on boundary faces we do not have two contributions so the weight should be doubled.
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for(auto &v : refinedOut.vert)
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if(v_cnH[v]>0) v.P() /= v_cnH[&v];
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// Third step compute new the position of the original vertices
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for(auto &f : baseIn.face)
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{
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Point3f center = refinedOut.vert[faceMap[tri::Index(baseIn,f)]].P();
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// for each vertex of the face we add to its position
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// the coords of the baricenter and of the two vertices adjacent to it
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for(int i=0;i<f.VN();i++)
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{
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float val = v_valH[f.V(i)];
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float val1 = (val -2.0)/(val*val);
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float val2 = 1.0/(val*val);
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int v0 = tri::Index(baseIn,f.V0(i));
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int v1 = tri::Index(baseIn,f.V1(i));
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if(v0>v1) std::swap(v0,v1);
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Point3f edgep = refinedOut.vert[edgeMap[std::make_pair(v0,v1)]].P();
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refinedOut.vert[tri::Index(baseIn,f.V(i))].P() += f.V(i)->P() * val1;
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refinedOut.vert[tri::Index(baseIn,f.V(i))].P() += center * val2;
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refinedOut.vert[tri::Index(baseIn,f.V(i))].P() += edgep * val2;
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}
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}
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printf( "Mesh has %i vert and %i faces\n", refinedOut.VN(), refinedOut.FN() );
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// Final step. Create Connectivity: a new face for each wedge of each face of the original mesh
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for(auto &f : baseIn.face)
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{
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// loop over all wedge of the face
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for(int i=0;i<f.VN();i++)
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{
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int e00 = tri::Index(baseIn,f.V0(i));
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int e01 = tri::Index(baseIn,f.V1(i));
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int e10 = tri::Index(baseIn,f.V0(i));
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int e11 = tri::Index(baseIn,f.V((i+f.VN()-1)%f.VN()));
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if(e00>e01) std::swap(e00,e01);
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if(e10>e11) std::swap(e10,e11);
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// retrieve the edge vertices
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auto e1it = edgeMap.find(std::make_pair(e00,e01));
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auto e2it = edgeMap.find(std::make_pair(e10,e11));
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// retrieve the face vertex
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auto fit = faceMap.find(tri::Index(baseIn,f));
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auto v0p = &refinedOut.vert[tri::Index(baseIn,f.V(i))];
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auto v1p = &refinedOut.vert[e1it->second];
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auto v2p = &refinedOut.vert[fit->second];
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auto v3p = &refinedOut.vert[e2it->second];
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tri::Allocator<PolyMeshType>::AddQuadFace(refinedOut, v0p, v1p, v2p, v3p);
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}
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}// fprintf(stdout,"Refining starting \n");fflush(stdout);
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tri::Allocator<PolyMeshType>::template DeletePerVertexAttribute<int>(refinedOut,v_cnH);
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// for the input mesh we keep an attribute with the valence of the vertices
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tri::Allocator<PolyMeshType>:: template DeletePerVertexAttribute<int>(baseIn,v_valH);
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} // end refine Function
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}; // end CatmullClark class
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} // end namespace tri
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} // end namespace vcg
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