97 lines
3.0 KiB
C++
97 lines
3.0 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) 2018 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_exists_near.h"
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template <
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typename DeriveduE,
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typename DerivedEMAP,
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typename uE2EType,
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typename Index>
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IGL_INLINE bool igl::edge_exists_near(
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const Eigen::MatrixBase<DeriveduE> & uE,
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const Eigen::MatrixBase<DerivedEMAP> & EMAP,
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const std::vector<std::vector< uE2EType> > & uE2E,
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const Index & a,
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const Index & b,
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const Index & uei)
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{
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std::vector<Index> face_queue;
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face_queue.reserve(32);
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std::vector<Index> pushed;
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// 32 is faster than 8
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pushed.reserve(32);
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assert(a!=b);
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// starting with the (2) faces incident on e, consider all faces
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// incident on edges containing either a or b.
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//
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// face_queue Queue containing faces incident on exactly one of a/b
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// Using a vector seems mildly faster
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assert(EMAP.size()%3 == 0);
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const Index num_faces = EMAP.size()/3;
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const Index f1 = uE2E[uei][0]%num_faces;
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const Index f2 = uE2E[uei][1]%num_faces;
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// map is faster than unordered_map here, and vector + brute force
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// is_member check is even faster
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face_queue.push_back(f1);
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pushed.push_back(f1);
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face_queue.push_back(f2);
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pushed.push_back(f2);
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while(!face_queue.empty())
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{
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const Index f = face_queue.back();
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face_queue.pop_back();
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// consider each edge of this face
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for(int c = 0;c<3;c++)
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{
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// Unique edge id
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const Index uec = EMAP(c*num_faces+f);
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const Index s = uE(uec,0);
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const Index d = uE(uec,1);
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const bool ona = s == a || d == a;
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const bool onb = s == b || d == b;
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// Is this the edge we're looking for?
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if(ona && onb)
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{
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return true;
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}
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// not incident on either?
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if(!ona && !onb)
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{
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continue;
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}
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// loop over all incident half-edges
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for(const auto & he : uE2E[uec])
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{
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// face of this he
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const Index fhe = he%num_faces;
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bool already_pushed = false;
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for(const auto & fp : pushed)
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{
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if(fp == fhe)
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{
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already_pushed = true;
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break;
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}
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}
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if(!already_pushed)
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{
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pushed.push_back(fhe);
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face_queue.push_back(fhe);
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}
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}
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}
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}
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return false;
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}
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#ifdef IGL_STATIC_LIBRARY
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// Explicit template instantiation
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// generated by autoexplicit.sh
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template bool igl::edge_exists_near<Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, 1, 0, -1, 1>, int, int>(Eigen::MatrixBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, Eigen::MatrixBase<Eigen::Matrix<int, -1, 1, 0, -1, 1> > const&, std::vector<std::vector<int, std::allocator<int> >, std::allocator<std::vector<int, std::allocator<int> > > > const&, int const&, int const&, int const&);
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#endif
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