101 lines
2.8 KiB
C++
101 lines
2.8 KiB
C++
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// 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 "bfs_orient.h"
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#include "orientable_patches.h"
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#include <Eigen/Sparse>
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#include <queue>
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template <typename DerivedF, typename DerivedFF, typename DerivedC>
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IGL_INLINE void igl::bfs_orient(
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const Eigen::PlainObjectBase<DerivedF> & F,
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Eigen::PlainObjectBase<DerivedFF> & FF,
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Eigen::PlainObjectBase<DerivedC> & C)
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{
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using namespace Eigen;
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using namespace std;
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SparseMatrix<int> A;
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orientable_patches(F,C,A);
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// number of faces
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const int m = F.rows();
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// number of patches
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const int num_cc = C.maxCoeff()+1;
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VectorXi seen = VectorXi::Zero(m);
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// Edge sets
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const int ES[3][2] = {{1,2},{2,0},{0,1}};
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if(&FF != &F)
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{
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FF = F;
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}
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// loop over patches
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#pragma omp parallel for
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for(int c = 0;c<num_cc;c++)
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{
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queue<int> Q;
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// find first member of patch c
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for(int f = 0;f<FF.rows();f++)
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{
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if(C(f) == c)
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{
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Q.push(f);
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break;
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}
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}
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assert(!Q.empty());
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while(!Q.empty())
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{
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const int f = Q.front();
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Q.pop();
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if(seen(f) > 0)
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{
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continue;
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}
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seen(f)++;
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// loop over neighbors of f
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for(typename SparseMatrix<int>::InnerIterator it (A,f); it; ++it)
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{
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// might be some lingering zeros, and skip self-adjacency
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if(it.value() != 0 && it.row() != f)
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{
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const int n = it.row();
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assert(n != f);
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// loop over edges of f
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for(int efi = 0;efi<3;efi++)
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{
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// efi'th edge of face f
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Vector2i ef(FF(f,ES[efi][0]),FF(f,ES[efi][1]));
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// loop over edges of n
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for(int eni = 0;eni<3;eni++)
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{
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// eni'th edge of face n
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Vector2i en(FF(n,ES[eni][0]),FF(n,ES[eni][1]));
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// Match (half-edges go same direction)
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if(ef(0) == en(0) && ef(1) == en(1))
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{
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// flip face n
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FF.row(n) = FF.row(n).reverse().eval();
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}
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}
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}
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// add neighbor to queue
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Q.push(n);
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}
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}
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}
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}
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// make sure flip is OK if &FF = &F
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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::bfs_orient<Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, 1, 0, -1, 1> >(Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> >&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, 1, 0, -1, 1> >&);
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#endif
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