CGAL 5.6.1 - Triangulated Surface Mesh Segmentation
Surface_mesh_segmentation/segmentation_with_facet_ids_example.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Polyhedron_items_with_id_3.h>
#include <CGAL/Polyhedron_3.h>
#include <CGAL/mesh_segmentation.h>
#include <CGAL/property_map.h>
#include <iostream>
#include <fstream>
typedef CGAL::Polyhedron_3<K, CGAL::Polyhedron_items_with_id_3> Polyhedron;
typedef boost::graph_traits<Polyhedron>::face_descriptor face_descriptor;
// Property map associating a face with an integer as id to an
// element in a vector stored internally
template<class ValueType>
struct Face_with_id_pmap
: public boost::put_get_helper<ValueType&,
Face_with_id_pmap<ValueType> >
{
typedef face_descriptor key_type;
typedef ValueType value_type;
typedef value_type& reference;
typedef boost::lvalue_property_map_tag category;
Face_with_id_pmap(
std::vector<ValueType>& internal_vector
) : internal_vector(internal_vector) { }
reference operator[](key_type key) const
{ return internal_vector[key->id()]; }
private:
std::vector<ValueType>& internal_vector;
};
int main()
{
// create and read Polyhedron
Polyhedron mesh;
std::ifstream input(CGAL::data_file_path("meshes/cactus.off"));
if ( !input || !(input >> mesh) || mesh.empty() || ( !CGAL::is_triangle_mesh(mesh)) ) {
std::cerr << "Input is not a triangle mesh" << std::endl;
return EXIT_FAILURE;
}
// assign id field for each face
std::size_t face_id = 0;
for(face_descriptor f : faces( mesh) ) {
f->id() = face_id++;
}
// create a property-map for SDF values
std::vector<double> sdf_values(num_faces(mesh));
Face_with_id_pmap<double> sdf_property_map(sdf_values);
CGAL::sdf_values(mesh, sdf_property_map);
// access SDF values (with constant-complexity)
for(face_descriptor f : faces(mesh)) {
std::cout << sdf_property_map[f] << " ";
}
std::cout << std::endl;
// create a property-map for segment-ids
std::vector<std::size_t> segment_ids(num_faces(mesh));
Face_with_id_pmap<std::size_t> segment_property_map(segment_ids);
CGAL::segmentation_from_sdf_values(mesh, sdf_property_map, segment_property_map);
// access segment-ids (with constant-complexity)
for(face_descriptor f : faces(mesh)) {
std::cout << segment_property_map[f] << " ";
}
std::cout << std::endl;
return EXIT_SUCCESS;
}