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Diffstat (limited to 'src/Contraction/example/Garland_heckbert.cpp')
| -rw-r--r-- | src/Contraction/example/Garland_heckbert.cpp | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/src/Contraction/example/Garland_heckbert.cpp b/src/Contraction/example/Garland_heckbert.cpp new file mode 100644 index 00000000..5b178ff9 --- /dev/null +++ b/src/Contraction/example/Garland_heckbert.cpp @@ -0,0 +1,195 @@ +/* + * Garland_heckbert.h + * Created on: Feb 10, 2015 + * This file is part of the Gudhi Library. The Gudhi library + * (Geometric Understanding in Higher Dimensions) is a generic C++ + * library for computational topology. + * + * Author(s): David Salinas + * + * Copyright (C) 2014 INRIA Sophia Antipolis-Méditerranée (France) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + */ + + +#ifndef GARLAND_HECKBERT_H_ +#define GARLAND_HECKBERT_H_ + +#include <boost/timer/timer.hpp> +#include <iostream> +#include "gudhi/Point.h" +#include "gudhi/Edge_contraction.h" +#include "gudhi/Skeleton_blocker.h" +#include "gudhi/Off_reader.h" + +#include "Garland_heckbert/Error_quadric.h" + +using namespace std; +using namespace Gudhi; +using namespace skbl; +using namespace contraction; + + +struct Geometry_trait{ + typedef Point_d Point; +}; + +/** + * The vertex stored in the complex contains a quadric. + */ +struct Garland_heckbert_traits : public Skeleton_blocker_simple_geometric_traits<Geometry_trait> { + +public: + struct Garland_heckbert_vertex : public Simple_geometric_vertex{ + Error_quadric<Geometry_trait::Point> quadric; + }; + typedef Garland_heckbert_vertex Graph_vertex; +}; + +typedef Skeleton_blocker_geometric_complex< Garland_heckbert_traits > Complex; +typedef Edge_profile<Complex> EdgeProfile; +typedef Skeleton_blocker_contractor<Complex> Complex_contractor; + + +/** + * How the new vertex is placed after an edge collapse : here it is placed at + * the point minimizing the cost of the quadric. + */ +class GH_placement : public Gudhi::contraction::Placement_policy<EdgeProfile>{ + Complex& complex_; +public: + typedef typename Gudhi::contraction::Placement_policy<EdgeProfile>::Placement_type Placement_type; + + GH_placement(Complex& complex):complex_(complex){} + + Placement_type operator()(const EdgeProfile& profile) const override{ + auto sum_quad(profile.v0().quadric); + sum_quad += profile.v1().quadric; + + boost::optional<Point> min_quadric_pt(sum_quad.min_cost()); + if (min_quadric_pt) + return Placement_type(*min_quadric_pt); + else + return profile.p0(); + } +}; + +/** + * How much cost an edge collapse : here the costs is given by a quadric + * which expresses a squared distances with triangles planes. + */ +class GH_cost : public Gudhi::contraction::Cost_policy<EdgeProfile>{ + Complex& complex_; +public: + + typedef typename Gudhi::contraction::Cost_policy<EdgeProfile>::Cost_type Cost_type; + + GH_cost(Complex& complex):complex_(complex){} + + Cost_type operator()( EdgeProfile const& profile, boost::optional<Point> const& new_point ) const override { + Cost_type res; + if (new_point){ + auto sum_quad(profile.v0().quadric); + sum_quad += profile.v1().quadric; + res = sum_quad.cost(*new_point); + } + return res; + } +}; + +/** + * Visitor that is called at several moment. + * Here we initializes the quadrics of every vertex at the on_started call back + * and we update them when contracting an edge (the quadric become the sum of both quadrics). + */ +class GH_visitor: public Gudhi::contraction::Contraction_visitor<EdgeProfile> { + Complex& complex_; +public: + GH_visitor(Complex& complex):complex_(complex){} + + //Compute quadrics for every vertex v + //The quadric of v consists in the sum of quadric + //of every triangles passing through v weighted by its area + void on_started(Complex & complex) override{ + for(auto v : complex.vertex_range()){ + auto & quadric_v(complex[v].quadric); + for(auto t : complex.triangle_range(v)){ + auto t_it = t.begin(); + const auto& p0(complex.point(*t_it++)); + const auto& p1(complex.point(*t_it++)); + const auto& p2(complex.point(*t_it++)); + quadric_v+=Error_quadric<Point>(p0,p1,p2); + } + } + } + + /** + * @brief Called when an edge is about to be contracted and replaced by a vertex whose position is *placement. + */ + void on_contracting(EdgeProfile const &profile, boost::optional< Point > placement) + override{ + profile.v0().quadric += profile.v1().quadric; + } +}; + + +int main(int argc, char *argv[]){ + if (argc!=4){ + std::cerr << "Usage "<<argv[0]<<" input.off output.off N to load the file input.off, contract N edges and save the result to output.off.\n"; + return EXIT_FAILURE; + } + + Complex complex; + + // load the points + Skeleton_blocker_off_reader<Complex> off_reader(argv[1],complex); + if(!off_reader.is_valid()){ + std::cerr << "Unable to read file:"<<argv[1]<<std::endl; + return EXIT_FAILURE; + } + + std::cout << "Load complex with "<<complex.num_vertices()<<" vertices"<<std::endl; + + + int num_contractions = atoi(argv[3]); + + boost::timer::auto_cpu_timer t; + + // constructs the contractor object with Garland Heckbert policies. + Complex_contractor contractor(complex, + new GH_cost(complex), + new GH_placement(complex), + contraction::make_link_valid_contraction<EdgeProfile>(), + new GH_visitor(complex) + ); + + std::cout<<"Contract "<<num_contractions<<" edges"<<std::endl; + contractor.contract_edges(num_contractions); + + std::cout << "Final complex has "<< + complex.num_vertices()<<" vertices, "<< + complex.num_edges()<<" edges and" << + complex.num_triangles()<<" triangles."<<std::endl; + + //write simplified complex + Skeleton_blocker_off_writer<Complex> off_writer(argv[2],complex); + + return EXIT_SUCCESS; +} + + + +#endif /* GARLAND_HECKBERT_H_ */ |