106 lines
3.6 KiB
C++
106 lines
3.6 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 "orientable_patches.h"
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#include "vertex_components.h"
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#include "sort.h"
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#include "unique_rows.h"
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#include <vector>
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#include <iostream>
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template <typename DerivedF, typename DerivedC, typename AScalar>
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IGL_INLINE void igl::orientable_patches(
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const Eigen::PlainObjectBase<DerivedF> & F,
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Eigen::PlainObjectBase<DerivedC> & C,
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Eigen::SparseMatrix<AScalar> & A)
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{
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using namespace Eigen;
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using namespace std;
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// simplex size
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assert(F.cols() == 3);
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// List of all "half"-edges: 3*#F by 2
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Matrix<typename DerivedF::Scalar, Dynamic, 2> allE,sortallE,uE;
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allE.resize(F.rows()*3,2);
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Matrix<int,Dynamic,2> IX;
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VectorXi IA,IC;
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allE.block(0*F.rows(),0,F.rows(),1) = F.col(1);
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allE.block(0*F.rows(),1,F.rows(),1) = F.col(2);
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allE.block(1*F.rows(),0,F.rows(),1) = F.col(2);
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allE.block(1*F.rows(),1,F.rows(),1) = F.col(0);
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allE.block(2*F.rows(),0,F.rows(),1) = F.col(0);
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allE.block(2*F.rows(),1,F.rows(),1) = F.col(1);
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// Sort each row
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sort(allE,2,true,sortallE,IX);
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//IC(i) tells us where to find sortallE(i,:) in uE:
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// so that sortallE(i,:) = uE(IC(i),:)
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unique_rows(sortallE,uE,IA,IC);
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// uE2FT(e,f) = 1 means face f is adjacent to unique edge e
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vector<Triplet<AScalar> > uE2FTijv(IC.rows());
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for(int e = 0;e<IC.rows();e++)
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{
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uE2FTijv[e] = Triplet<AScalar>(e%F.rows(),IC(e),1);
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}
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SparseMatrix<AScalar> uE2FT(F.rows(),uE.rows());
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uE2FT.setFromTriplets(uE2FTijv.begin(),uE2FTijv.end());
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// kill non-manifold edges
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for(int j=0; j<(int)uE2FT.outerSize();j++)
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{
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int degree = 0;
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for(typename SparseMatrix<AScalar>::InnerIterator it (uE2FT,j); it; ++it)
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{
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degree++;
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}
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// Iterate over inside
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if(degree > 2)
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{
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for(typename SparseMatrix<AScalar>::InnerIterator it (uE2FT,j); it; ++it)
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{
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uE2FT.coeffRef(it.row(),it.col()) = 0;
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}
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}
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}
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// Face-face Adjacency matrix
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SparseMatrix<AScalar> uE2F;
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uE2F = uE2FT.transpose().eval();
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A = uE2FT*uE2F;
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// All ones
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for(int j=0; j<A.outerSize();j++)
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{
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// Iterate over inside
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for(typename SparseMatrix<AScalar>::InnerIterator it (A,j); it; ++it)
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{
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if(it.value() > 1)
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{
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A.coeffRef(it.row(),it.col()) = 1;
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}
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}
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}
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//% Connected components are patches
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//%C = vertex_components(A); % alternative to graphconncomp from matlab_bgl
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//[~,C] = graphconncomp(A);
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// graph connected components
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vertex_components(A,C);
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}
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template <typename DerivedF, typename DerivedC>
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IGL_INLINE void igl::orientable_patches(
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const Eigen::PlainObjectBase<DerivedF> & F,
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Eigen::PlainObjectBase<DerivedC> & C)
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{
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Eigen::SparseMatrix<typename DerivedF::Scalar> A;
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return orientable_patches(F,C,A);
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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::orientable_patches<Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, 1, 0, -1, 1>, int>(Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, 1, 0, -1, 1> >&, Eigen::SparseMatrix<int, 0, int>&);
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template void igl::orientable_patches<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> >&);
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#endif
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