104 lines
2.4 KiB
C++
104 lines
2.4 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 "faces_first.h"
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#include <vector>
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#include <Eigen/Dense>
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template <typename MatV, typename MatF, typename VecI>
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IGL_INLINE void igl::faces_first(
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const MatV & V,
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const MatF & F,
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MatV & RV,
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MatF & RF,
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VecI & IM)
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{
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assert(&V != &RV);
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assert(&F != &RF);
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using namespace std;
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using namespace Eigen;
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vector<bool> in_face(V.rows());
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for(int i = 0; i<F.rows(); i++)
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{
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for(int j = 0; j<F.cols(); j++)
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{
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in_face[F(i,j)] = true;
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}
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}
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// count number of vertices not in faces
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int num_in_F = 0;
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for(int i = 0;i<V.rows();i++)
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{
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num_in_F += (in_face[i]?1:0);
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}
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// list of unique vertices that occur in F
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VectorXi U(num_in_F);
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// list of unique vertices that do not occur in F
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VectorXi NU(V.rows()-num_in_F);
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int Ui = 0;
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int NUi = 0;
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// loop over vertices
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for(int i = 0;i<V.rows();i++)
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{
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if(in_face[i])
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{
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U(Ui) = i;
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Ui++;
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}else
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{
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NU(NUi) = i;
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NUi++;
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}
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}
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IM.resize(V.rows());
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// reindex vertices that occur in faces to be first
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for(int i = 0;i<U.size();i++)
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{
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IM(U(i)) = i;
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}
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// reindex vertices that do not occur in faces to come after those that do
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for(int i = 0;i<NU.size();i++)
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{
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IM(NU(i)) = i+U.size();
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}
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RF.resizeLike(F);
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// Reindex faces
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for(int i = 0; i<F.rows(); i++)
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{
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for(int j = 0; j<F.cols(); j++)
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{
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RF(i,j) = IM(F(i,j));
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}
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}
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RV.resizeLike(V);
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// Reorder vertices
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for(int i = 0;i<V.rows();i++)
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{
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RV.row(IM(i)) = V.row(i);
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}
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}
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template <typename MatV, typename MatF, typename VecI>
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IGL_INLINE void igl::faces_first(
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MatV & V,
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MatF & F,
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VecI & IM)
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{
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MatV RV;
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// Copying F may not be needed, seems RF = F is safe (whereas RV = V is not)
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MatF RF;
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igl::faces_first(V,F,RV,RF,IM);
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V = RV;
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F = RF;
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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::faces_first<Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, 1, 0, -1, 1> >(Eigen::Matrix<double, -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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