CGAL 5.6.3 - Triangulated Surface Mesh Segmentation

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Surface_mesh_segmentation/segmentation_from_sdf_values_SM_example.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/mesh_segmentation.h>
#include <CGAL/Polygon_mesh_processing/IO/polygon_mesh_io.h>
#include <CGAL/property_map.h>
#include <iostream>
#include <fstream>
typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
typedef Kernel::Point_3 Point_3;
typedef CGAL::Surface_mesh<Point_3> Mesh;
typedef boost::graph_traits<Mesh>::vertex_descriptor vertex_descriptor;
typedef boost::graph_traits<Mesh>::face_descriptor face_descriptor;
int main(int argc, char** argv )
{
const std::string filename = (argc > 1) ? argv[1] : CGAL::data_file_path("meshes/cactus.off");
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;
}
typedef Mesh::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;
// compute SDF values
// We can't use default parameters for number of rays, and cone angle
// and the postprocessing
CGAL::sdf_values(mesh, sdf_property_map, 2.0 / 3.0 * CGAL_PI, 25, true);
// create a property-map for segment-ids
typedef Mesh::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);
std::cout << "Number of segments: " << number_of_segments << std::endl;
// print segment-ids
for(face_descriptor fd : faces(mesh)){
// ids are between [0, number_of_segments -1]
std::cout << segment_property_map[fd] << " ";
}
std::cout << std::endl;
const std::size_t number_of_clusters = 4; // use 4 clusters in soft clustering
const double smoothing_lambda = 0.3; // importance of surface features, suggested to be in-between [0,1]
// Note that we can use the same SDF values (sdf_property_map) over and over again for segmentation.
// This feature is relevant for segmenting the mesh several times with different parameters.
CGAL::segmentation_from_sdf_values(mesh, sdf_property_map, segment_property_map, number_of_clusters, smoothing_lambda);
return EXIT_SUCCESS;
}
CGAL::Exact_predicates_inexact_constructions_kernel
CGAL::Surface_mesh
CGAL::Surface_mesh::add_property_map
std::pair< Property_map< I, T >, bool > add_property_map(std::string name=std::string(), const T t=T())
Kernel::Point_3
CGAL::is_triangle_mesh
bool is_triangle_mesh(const FaceGraph &g)
CGAL::sdf_values
std::pair< double, double > sdf_values(const TriangleMesh &triangle_mesh, SDFPropertyMap sdf_values_map, double cone_angle=2.0/3.0 *CGAL_PI, std::size_t number_of_rays=25, bool postprocess=true, PointPropertyMap ppmap=PointPropertyMap(), GeomTraits traits=GeomTraits())
Function computing the Shape Diameter Function over a surface mesh.
Definition: mesh_segmentation.h:96
CGAL::segmentation_from_sdf_values
std::size_t segmentation_from_sdf_values(const TriangleMesh &triangle_mesh, SDFPropertyMap sdf_values_map, SegmentPropertyMap segment_ids, std::size_t number_of_clusters=5, double smoothing_lambda=0.26, bool output_cluster_ids=false, PointPropertyMap ppmap=PointPropertyMap(), GeomTraits traits=GeomTraits())
Function computing the segmentation of a surface mesh given an SDF value per facet.
Definition: mesh_segmentation.h:191
Kernel