Surface_mesh_approximation/vsa_segmentation_example.cpp

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
 
#include <CGAL/Surface_mesh_approximation/approximate_triangle_mesh.h>
#include <CGAL/Polygon_mesh_processing/IO/polygon_mesh_io.h>
 
#include <iostream>
#include <fstream>
 
typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
typedef CGAL::Surface_mesh<Kernel::Point_3> Mesh;
typedef boost::graph_traits<Mesh>::face_descriptor face_descriptor;
typedef Mesh::Property_map<face_descriptor, std::size_t> Face_proxy_pmap;
 
namespace VSA = CGAL::Surface_mesh_approximation;
 
int main(int argc, char** argv)
{
  const std::string filename = (argc > 1) ? argv[1] : CGAL::data_file_path("meshes/bear.off");
 
  // reads input surface triangle mesh
  Mesh mesh;
  if(!CGAL::Polygon_mesh_processing::IO::read_polygon_mesh(filename, mesh) ||
     !CGAL::is_triangle_mesh(mesh))
  {
    std::cerr << "Invalid input file." << std::endl;
    return EXIT_FAILURE;
  }
 
  // face proxy index property map
  Face_proxy_pmap fpxmap = mesh.add_property_map<face_descriptor, std::size_t>("f:proxy_id", 0).first;
 
  // free function interface with named parameters
  VSA::approximate_triangle_mesh(mesh,
                                 CGAL::parameters::max_number_of_proxies(200). // first stop criterion
                                                   min_error_drop(0.05). // second stop criterion
                                                   number_of_iterations(30). // number of relaxation iterations after seeding
                                                   face_proxy_map(fpxmap)); // output face-proxy map
 
  // iterates over faces and outputs segment id to console
  for(face_descriptor f : faces(mesh))
    std::cout << fpxmap[f] << std::endl;
 
  return EXIT_SUCCESS;
}