\( \newcommand{\E}{\mathrm{E}} \) \( \newcommand{\A}{\mathrm{A}} \) \( \newcommand{\R}{\mathrm{R}} \) \( \newcommand{\N}{\mathrm{N}} \) \( \newcommand{\Q}{\mathrm{Q}} \) \( \newcommand{\Z}{\mathrm{Z}} \) \( \def\ccSum #1#2#3{ \sum_{#1}^{#2}{#3} } \def\ccProd #1#2#3{ \sum_{#1}^{#2}{#3} }\)
CGAL 5.0.2 - CGAL and the Boost Graph Library
Surface_mesh_segmentation/extract_segmentation_into_mesh_example.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/boost/graph/graph_traits_Surface_mesh.h>
#include <CGAL/boost/graph/Face_filtered_graph.h>
#include <CGAL/Polygon_mesh_processing/measure.h>
#include <CGAL/boost/graph/copy_face_graph.h>
#include <CGAL/mesh_segmentation.h>
#include <iostream>
#include <fstream>
#include <sstream>
typedef boost::graph_traits<SM>::face_descriptor face_descriptor;
int main(int argc, char** argv )
{
SM mesh;
if (argc==2){
std::ifstream input(argv[1]);
input >> mesh;
} else {
std::ifstream cactus("data/cactus.off");
cactus >> mesh;
}
typedef SM::Property_map<face_descriptor,double> Facet_double_map;
Facet_double_map sdf_property_map;
sdf_property_map = mesh.add_property_map<face_descriptor,double>("f:sdf").first;
CGAL::sdf_values(mesh, sdf_property_map);
// create a property-map for segment-ids
typedef SM::Property_map<face_descriptor, std::size_t> Facet_int_map;
Facet_int_map segment_property_map = mesh.add_property_map<face_descriptor,std::size_t>("f:sid").first;;
// segment the mesh using default parameters for number of levels, and smoothing lambda
// Any other scalar values can be used instead of using SDF values computed using the CGAL function
std::size_t number_of_segments = CGAL::segmentation_from_sdf_values(mesh, sdf_property_map, segment_property_map);
typedef CGAL::Face_filtered_graph<SM> Filtered_graph;
//print area of each segment and then put it in a Mesh and print it in an OFF file
Filtered_graph segment_mesh(mesh, 0, segment_property_map);
for(std::size_t id = 0; id < number_of_segments; ++id)
{
if(id > 0)
segment_mesh.set_selected_faces(id, segment_property_map);
std::cout << "Segment "<<id<<"'s area is : "<<CGAL::Polygon_mesh_processing::area(segment_mesh)<<std::endl;
SM out;
CGAL::copy_face_graph(segment_mesh, out);
std::ostringstream oss;
oss << "Segment_" << id<<".off";
std::ofstream os(oss.str().data());
os<<out;
}
}