111 lines
3.5 KiB
C++
111 lines
3.5 KiB
C++
// This file is part of libigl, a simple c++ geometry processing library.
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//
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// Copyright (C) 2013 Alec Jacobson <alecjacobson@gmail.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla Public License
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// v. 2.0. If a copy of the MPL was not distributed with this file, You can
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// obtain one at http://mozilla.org/MPL/2.0/.
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#include "edge_topology.h"
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#include "is_edge_manifold.h"
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#include <algorithm>
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template<typename DerivedV, typename DerivedF>
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IGL_INLINE void igl::edge_topology(
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const Eigen::PlainObjectBase<DerivedV>& V,
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const Eigen::PlainObjectBase<DerivedF>& F,
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Eigen::MatrixXi& EV,
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Eigen::MatrixXi& FE,
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Eigen::MatrixXi& EF)
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{
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// Only needs to be edge-manifold
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if (V.rows() ==0 || F.rows()==0)
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{
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EV = Eigen::MatrixXi::Constant(0,2,-1);
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FE = Eigen::MatrixXi::Constant(0,3,-1);
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EF = Eigen::MatrixXi::Constant(0,2,-1);
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return;
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}
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assert(igl::is_edge_manifold(F));
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std::vector<std::vector<int> > ETT;
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for(int f=0;f<F.rows();++f)
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for (int i=0;i<3;++i)
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{
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// v1 v2 f vi
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int v1 = F(f,i);
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int v2 = F(f,(i+1)%3);
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if (v1 > v2) std::swap(v1,v2);
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std::vector<int> r(4);
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r[0] = v1; r[1] = v2;
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r[2] = f; r[3] = i;
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ETT.push_back(r);
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}
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std::sort(ETT.begin(),ETT.end());
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// count the number of edges (assume manifoldness)
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int En = 1; // the last is always counted
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for(int i=0;i<int(ETT.size())-1;++i)
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if (!((ETT[i][0] == ETT[i+1][0]) && (ETT[i][1] == ETT[i+1][1])))
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++En;
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EV = Eigen::MatrixXi::Constant((int)(En),2,-1);
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FE = Eigen::MatrixXi::Constant((int)(F.rows()),3,-1);
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EF = Eigen::MatrixXi::Constant((int)(En),2,-1);
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En = 0;
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for(unsigned i=0;i<ETT.size();++i)
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{
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if (i == ETT.size()-1 ||
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!((ETT[i][0] == ETT[i+1][0]) && (ETT[i][1] == ETT[i+1][1]))
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)
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{
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// Border edge
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std::vector<int>& r1 = ETT[i];
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EV(En,0) = r1[0];
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EV(En,1) = r1[1];
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EF(En,0) = r1[2];
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FE(r1[2],r1[3]) = En;
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}
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else
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{
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std::vector<int>& r1 = ETT[i];
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std::vector<int>& r2 = ETT[i+1];
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EV(En,0) = r1[0];
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EV(En,1) = r1[1];
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EF(En,0) = r1[2];
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EF(En,1) = r2[2];
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FE(r1[2],r1[3]) = En;
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FE(r2[2],r2[3]) = En;
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++i; // skip the next one
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}
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++En;
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}
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// Sort the relation EF, accordingly to EV
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// the first one is the face on the left of the edge
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for(unsigned i=0; i<EF.rows(); ++i)
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{
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int fid = EF(i,0);
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bool flip = true;
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// search for edge EV.row(i)
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for (unsigned j=0; j<3; ++j)
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{
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if ((F(fid,j) == EV(i,0)) && (F(fid,(j+1)%3) == EV(i,1)))
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flip = false;
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}
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if (flip)
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{
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int tmp = EF(i,0);
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EF(i,0) = EF(i,1);
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EF(i,1) = tmp;
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}
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}
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}
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#ifdef IGL_STATIC_LIBRARY
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// Explicit template instantiation
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template void igl::edge_topology<Eigen::Matrix<double, -1, 3, 0, -1, 3>, Eigen::Matrix<int, -1, 3, 0, -1, 3> >(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, 3, 0, -1, 3> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, 3, 0, -1, 3> > const&, Eigen::Matrix<int, -1, -1, 0, -1, -1>&, Eigen::Matrix<int, -1, -1, 0, -1, -1>&, Eigen::Matrix<int, -1, -1, 0, -1, -1>&);
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template void igl::edge_topology<Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1> >(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, Eigen::Matrix<int, -1, -1, 0, -1, -1>&, Eigen::Matrix<int, -1, -1, 0, -1, -1>&, Eigen::Matrix<int, -1, -1, 0, -1, -1>&);
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#endif
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