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#include <CGAL/Simple_cartesian.h>
#include <CGAL/Polyhedron_3.h>
// Simplification function
#include <CGAL/Surface_mesh_simplification/edge_collapse.h>
// Stop-condition policy
#include <CGAL/Surface_mesh_simplification/Policies/Edge_collapse/Edge_count_stop_predicate.h>
#include <iostream>
#include <fstream>
typedef CGAL::Simple_cartesian<double> Kernel;
typedef CGAL::Polyhedron_3<Kernel> Surface_mesh;
namespace SMS = CGAL::Surface_mesh_simplification;
int main(int argc, char** argv)
{
Surface_mesh surface_mesh;
const std::string filename = (argc > 1) ? argv[1] : CGAL::data_file_path("meshes/small_cube.off");
std::ifstream is(filename);
if(!is || !(is >> surface_mesh))
{
std::cerr << "Failed to read input mesh: " << filename << std::endl;
return EXIT_FAILURE;
}
if(!CGAL::is_triangle_mesh(surface_mesh))
{
std::cerr << "Input geometry is not triangulated." << std::endl;
return EXIT_FAILURE;
}
// This is a stop predicate (defines when the algorithm terminates).
// In this example, the simplification stops when the number of undirected edges
// left in the surface mesh drops below the specified number (1000)
const std::size_t edge_count_treshold = (argc > 2) ? std::stoi(argv[2]) : 1000;
SMS::Edge_count_stop_predicate<Surface_mesh> stop(edge_count_treshold);
// This the actual call to the simplification algorithm.
// The surface mesh and stop conditions are mandatory arguments.
// The index maps are needed because the vertices and edges
// of this surface mesh lack an "id()" field.
std::cout << "Collapsing edges of Polyhedron: " << filename << ", aiming for " << edge_count_treshold << " final edges..." << std::endl;
int r = SMS::edge_collapse(surface_mesh, stop,
CGAL::parameters::vertex_index_map(get(CGAL::vertex_external_index, surface_mesh))
.halfedge_index_map(get(CGAL::halfedge_external_index, surface_mesh)));
std::cout << "\nFinished!\n" << r << " edges removed.\n"
<< (surface_mesh.size_of_halfedges()/2) << " final edges.\n";
std::ofstream os(argc > 3 ? argv[3] : "out.off");
os.precision(17);
os << surface_mesh;
return EXIT_SUCCESS;
}
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