\( \newcommand{\E}{\mathrm{E}} \) \( \newcommand{\A}{\mathrm{A}} \) \( \newcommand{\R}{\mathrm{R}} \) \( \newcommand{\N}{\mathrm{N}} \) \( \newcommand{\Q}{\mathrm{Q}} \) \( \newcommand{\Z}{\mathrm{Z}} \) \( \def\ccSum #1#2#3{ \sum_{#1}^{#2}{#3} } \def\ccProd #1#2#3{ \sum_{#1}^{#2}{#3} }\)
CGAL 5.0 - CGAL and the Boost Graph Library
BGL_surface_mesh/surface_mesh_partition.cpp
#include <CGAL/Simple_cartesian.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/boost/graph/Face_filtered_graph.h>
#include <fstream>
#include <iostream>
int main(int argc, char** argv)
{
std::ifstream in((argc>1) ? argv[1] : "data/blobby.off");
int number_of_parts = (argc>2) ? atoi(argv[2]) : 8;
if(!in) {
std::cerr << "Error: could not read input file" << std::endl;
return EXIT_FAILURE;
}
SM sm;
CGAL::read_off(in, sm);
// The vertex <--> partition_id property map
typedef SM::Property_map<SM::Vertex_index, std::size_t> Vertex_id_map;
Vertex_id_map vertex_pid_map = sm.add_property_map<SM::Vertex_index, std::size_t>("v:pid").first;
// The face <--> partition_id property map
typedef SM::Property_map<SM::Face_index, std::size_t> Face_id_map;
Face_id_map face_pid_map = sm.add_property_map<SM::Face_index, std::size_t>("f:pid").first;
// Partition the mesh
CGAL::METIS::partition_dual_graph(sm, number_of_parts,
CGAL::parameters::vertex_partition_id_map(vertex_pid_map)
.face_partition_id_map(face_pid_map));
// Extract the part n°0 of the partition into a new, independent mesh
typedef CGAL::Face_filtered_graph<SM> Filtered_graph;
Filtered_graph filtered_sm(sm, 0 /*id of th part*/, face_pid_map);
CGAL_assertion(filtered_sm.is_selection_valid());
SM part_sm;
CGAL::copy_face_graph(filtered_sm, part_sm);
// Output the mesh extracted from subpart n°0
std::ofstream out("sm_part_0.off");
out.precision(17);
CGAL::write_off(out, part_sm);
// Output all the vertices that are in the part n°0
std::ofstream outxyz("out.xyz");
outxyz.precision(17);
boost::graph_traits<SM>::vertex_iterator vit, ve;
boost::tie(vit, ve) = vertices(sm);
for(; vit!=ve; ++vit)
{
if(get(vertex_pid_map, *vit) == 0)
outxyz << sm.point(*vit) << std::endl;
}
return EXIT_SUCCESS;
}