CGAL 5.6.2 - Polygon Mesh Processing
Polygon_mesh_processing/volume_connected_components.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/Polygon_mesh_processing/orientation.h>
#include <CGAL/Polygon_mesh_processing/IO/polygon_mesh_io.h>
#include <CGAL/boost/graph/Face_filtered_graph.h>
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
namespace params = CGAL::parameters;
int main(int argc, char** argv)
{
const std::string filename = (argc > 1) ? argv[1] : CGAL::data_file_path("meshes/blobby.off");
Surface_mesh mesh;
if(!PMP::IO::read_polygon_mesh(filename, mesh))
{
std::cerr << "Invalid input." << std::endl;
return 1;
}
// property map to assign a volume id for each face
Surface_mesh::Property_map<Surface_mesh::Face_index, std::size_t> vol_id_map =
mesh.add_property_map<Surface_mesh::Face_index, std::size_t>().first;
// fill the volume id map
std::vector<PMP::Volume_error_code> err_codes;
std::size_t nb_vol = PMP::volume_connected_components(mesh, vol_id_map,
params::error_codes(std::ref(err_codes)));
std::cout << "Found " << nb_vol << " volumes\n";
// write each volume in an OFF file
Filtered_graph vol_mesh(mesh, 0, vol_id_map);
for(std::size_t id = 0; id < nb_vol; ++id)
{
if(err_codes[id] != PMP::VALID_VOLUME)
std::cerr << "There is an issue with volume #" << id << "\n";
if(id > 0)
vol_mesh.set_selected_faces(id, vol_id_map);
Surface_mesh out;
CGAL::copy_face_graph(vol_mesh, out);
std::ostringstream oss;
oss << "vol_" << id <<".off";
std::ofstream os(oss.str().data());
os << out;
}
}