281 lines
11 KiB
C++
281 lines
11 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) 2015 Qingnan Zhou <qnzhou@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 "outer_element.h"
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#include <iostream>
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#include <vector>
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template <
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typename DerivedV,
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typename DerivedF,
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typename DerivedI,
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typename IndexType,
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typename DerivedA
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>
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IGL_INLINE void igl::outer_vertex(
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const Eigen::PlainObjectBase<DerivedV> & V,
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const Eigen::PlainObjectBase<DerivedF> & F,
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const Eigen::PlainObjectBase<DerivedI> & I,
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IndexType & v_index,
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Eigen::PlainObjectBase<DerivedA> & A)
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{
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// Algorithm:
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// Find an outer vertex (i.e. vertex reachable from infinity)
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// Return the vertex with the largest X value.
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// If there is a tie, pick the one with largest Y value.
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// If there is still a tie, pick the one with the largest Z value.
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// If there is still a tie, then there are duplicated vertices within the
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// mesh, which violates the precondition.
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typedef typename DerivedF::Scalar Index;
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const Index INVALID = std::numeric_limits<Index>::max();
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const size_t num_selected_faces = I.rows();
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std::vector<size_t> candidate_faces;
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Index outer_vid = INVALID;
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typename DerivedV::Scalar outer_val = 0;
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for (size_t i=0; i<num_selected_faces; i++)
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{
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size_t f = I(i);
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for (size_t j=0; j<3; j++)
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{
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Index v = F(f, j);
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auto vx = V(v, 0);
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if (outer_vid == INVALID || vx > outer_val)
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{
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outer_val = vx;
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outer_vid = v;
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candidate_faces = {f};
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} else if (v == outer_vid)
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{
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candidate_faces.push_back(f);
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} else if (vx == outer_val)
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{
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// Break tie.
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auto vy = V(v,1);
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auto vz = V(v, 2);
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auto outer_y = V(outer_vid, 1);
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auto outer_z = V(outer_vid, 2);
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assert(!(vy == outer_y && vz == outer_z));
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bool replace = (vy > outer_y) ||
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((vy == outer_y) && (vz > outer_z));
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if (replace)
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{
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outer_val = vx;
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outer_vid = v;
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candidate_faces = {f};
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}
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}
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}
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}
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assert(outer_vid != INVALID);
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assert(candidate_faces.size() > 0);
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v_index = outer_vid;
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A.resize(candidate_faces.size());
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std::copy(candidate_faces.begin(), candidate_faces.end(), A.data());
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}
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template<
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typename DerivedV,
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typename DerivedF,
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typename DerivedI,
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typename IndexType,
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typename DerivedA
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>
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IGL_INLINE void igl::outer_edge(
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const Eigen::PlainObjectBase<DerivedV> & V,
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const Eigen::PlainObjectBase<DerivedF> & F,
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const Eigen::PlainObjectBase<DerivedI> & I,
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IndexType & v1,
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IndexType & v2,
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Eigen::PlainObjectBase<DerivedA> & A) {
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// Algorithm:
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// Find an outer vertex first.
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// Find the incident edge with largest abs slope when projected onto XY plane.
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// If there is a tie, check the signed slope and use the positive one.
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// If there is still a tie, break it using the projected slope onto ZX plane.
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// If there is still a tie, again check the signed slope and use the positive one.
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// If there is still a tie, then there are multiple overlapping edges,
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// which violates the precondition.
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typedef typename DerivedV::Scalar Scalar;
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typedef typename DerivedV::Index Index;
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typedef typename Eigen::Matrix<Scalar, 3, 1> ScalarArray3;
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typedef typename Eigen::Matrix<typename DerivedF::Scalar, 3, 1> IndexArray3;
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const Index INVALID = std::numeric_limits<Index>::max();
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Index outer_vid;
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Eigen::Matrix<Index,Eigen::Dynamic,1> candidate_faces;
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outer_vertex(V, F, I, outer_vid, candidate_faces);
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const ScalarArray3& outer_v = V.row(outer_vid);
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assert(candidate_faces.size() > 0);
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auto get_vertex_index = [&](const IndexArray3& f, Index vid) -> Index
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{
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if (f[0] == vid) return 0;
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if (f[1] == vid) return 1;
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if (f[2] == vid) return 2;
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assert(false);
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return -1;
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};
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auto unsigned_value = [](Scalar v) -> Scalar {
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if (v < 0) return v * -1;
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else return v;
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};
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Scalar outer_slope_YX = 0;
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Scalar outer_slope_ZX = 0;
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Index outer_opp_vid = INVALID;
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bool infinite_slope_detected = false;
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std::vector<Index> incident_faces;
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auto check_and_update_outer_edge = [&](Index opp_vid, Index fid) {
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if (opp_vid == outer_opp_vid)
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{
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incident_faces.push_back(fid);
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return;
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}
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const ScalarArray3 opp_v = V.row(opp_vid);
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if (!infinite_slope_detected && outer_v[0] != opp_v[0])
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{
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// Finite slope
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const ScalarArray3 diff = opp_v - outer_v;
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const Scalar slope_YX = diff[1] / diff[0];
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const Scalar slope_ZX = diff[2] / diff[0];
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const Scalar u_slope_YX = unsigned_value(slope_YX);
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const Scalar u_slope_ZX = unsigned_value(slope_ZX);
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bool update = false;
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if (outer_opp_vid == INVALID) {
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update = true;
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} else {
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const Scalar u_outer_slope_YX = unsigned_value(outer_slope_YX);
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if (u_slope_YX > u_outer_slope_YX) {
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update = true;
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} else if (u_slope_YX == u_outer_slope_YX &&
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slope_YX > outer_slope_YX) {
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update = true;
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} else if (slope_YX == outer_slope_YX) {
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const Scalar u_outer_slope_ZX =
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unsigned_value(outer_slope_ZX);
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if (u_slope_ZX > u_outer_slope_ZX) {
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update = true;
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} else if (u_slope_ZX == u_outer_slope_ZX &&
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slope_ZX > outer_slope_ZX) {
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update = true;
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} else if (slope_ZX == u_outer_slope_ZX) {
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assert(false);
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}
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}
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}
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if (update) {
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outer_opp_vid = opp_vid;
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outer_slope_YX = slope_YX;
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outer_slope_ZX = slope_ZX;
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incident_faces = {fid};
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}
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} else if (!infinite_slope_detected)
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{
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// Infinite slope
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outer_opp_vid = opp_vid;
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infinite_slope_detected = true;
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incident_faces = {fid};
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}
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};
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const size_t num_candidate_faces = candidate_faces.size();
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for (size_t i=0; i<num_candidate_faces; i++)
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{
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const Index fid = candidate_faces(i);
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const IndexArray3& f = F.row(fid);
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size_t id = get_vertex_index(f, outer_vid);
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Index next_vid = f((id+1)%3);
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Index prev_vid = f((id+2)%3);
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check_and_update_outer_edge(next_vid, fid);
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check_and_update_outer_edge(prev_vid, fid);
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}
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v1 = outer_vid;
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v2 = outer_opp_vid;
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A.resize(incident_faces.size());
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std::copy(incident_faces.begin(), incident_faces.end(), A.data());
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}
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template<
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typename DerivedV,
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typename DerivedF,
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typename DerivedN,
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typename DerivedI,
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typename IndexType
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>
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IGL_INLINE void igl::outer_facet(
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const Eigen::PlainObjectBase<DerivedV> & V,
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const Eigen::PlainObjectBase<DerivedF> & F,
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const Eigen::PlainObjectBase<DerivedN> & N,
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const Eigen::PlainObjectBase<DerivedI> & I,
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IndexType & f,
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bool & flipped) {
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// Algorithm:
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// Find an outer edge.
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// Find the incident facet with the largest absolute X normal component.
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// If there is a tie, keep the one with positive X component.
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// If there is still a tie, pick the face with the larger signed index
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// (flipped face has negative index).
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typedef typename DerivedV::Scalar Scalar;
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typedef typename DerivedV::Index Index;
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const size_t INVALID = std::numeric_limits<size_t>::max();
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Index v1,v2;
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Eigen::Matrix<Index,Eigen::Dynamic,1> incident_faces;
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outer_edge(V, F, I, v1, v2, incident_faces);
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assert(incident_faces.size() > 0);
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auto generic_fabs = [&](const Scalar& val) -> const Scalar {
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if (val >= 0) return val;
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else return -val;
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};
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Scalar max_nx = 0;
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size_t outer_fid = INVALID;
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const size_t num_incident_faces = incident_faces.size();
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for (size_t i=0; i<num_incident_faces; i++)
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{
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const auto& fid = incident_faces(i);
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const Scalar nx = N(fid, 0);
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if (outer_fid == INVALID) {
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max_nx = nx;
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outer_fid = fid;
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} else {
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if (generic_fabs(nx) > generic_fabs(max_nx)) {
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max_nx = nx;
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outer_fid = fid;
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} else if (nx == -max_nx && nx > 0) {
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max_nx = nx;
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outer_fid = fid;
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} else if (nx == max_nx) {
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if ((max_nx >= 0 && outer_fid < fid) ||
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(max_nx < 0 && outer_fid > fid)) {
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max_nx = nx;
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outer_fid = fid;
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}
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}
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}
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}
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assert(outer_fid != INVALID);
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f = outer_fid;
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flipped = max_nx < 0;
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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::outer_facet<Eigen::Matrix<double, -1, 3, 0, -1, 3>, Eigen::Matrix<int, -1, 3, 0, -1, 3>, Eigen::Matrix<double, -1, 3, 0, -1, 3>, Eigen::Matrix<long, -1, 1, 0, -1, 1>, int>(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, 3, 0, -1, 3> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, 3, 0, -1, 3> > const&, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, 3, 0, -1, 3> > const&, Eigen::PlainObjectBase<Eigen::Matrix<long, -1, 1, 0, -1, 1> > const&, int&, bool&);
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template void igl::outer_facet<Eigen::Matrix<double, -1, -1, 1, -1, -1>, Eigen::Matrix<int, -1, -1, 1, -1, -1>, Eigen::Matrix<double, -1, -1, 1, -1, -1>, Eigen::Matrix<int, -1, -1, 1, -1, -1>, unsigned long>(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 1, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 1, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 1, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 1, -1, -1> > const&, unsigned long&, bool&);
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template void igl::outer_facet<Eigen::Matrix<double, -1, -1, 0, -1, -1>, Eigen::Matrix<int, -1, -1, 0, -1, -1>, Eigen::Matrix<double, -1, 3, 0, -1, 3>, Eigen::Matrix<int, -1, 1, 0, -1, 1>, int>(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, 3, 0, -1, 3> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, 1, 0, -1, 1> > const&, int&, bool&);
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template void igl::outer_facet<Eigen::Matrix<double, -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>, int>(Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> > const&, Eigen::PlainObjectBase<Eigen::Matrix<int, -1, 1, 0, -1, 1> > const&, int&, bool&);
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#endif
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