CGAL 5.5.2 - Polygon Mesh Processing
Polygon_mesh_processing/triangulate_faces_split_visitor_example.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/Polygon_mesh_processing/triangulate_faces.h>
#include <CGAL/boost/graph/copy_face_graph.h>
#include <iostream>
#include <fstream>
#include <map>
#include <string>
#include <unordered_map>
#include <utility>
typedef Kernel::Point_3 Point;
typedef CGAL::Surface_mesh<Point> Surface_mesh;
typedef boost::graph_traits<Surface_mesh>::face_descriptor face_descriptor;
class Insert_iterator
{
typedef std::unordered_map<face_descriptor,face_descriptor> Container;
Container& container;
public:
Insert_iterator(Container &c)
: container(c) {}
Insert_iterator&
operator=(const std::pair<face_descriptor, face_descriptor>& p)
{
container[p.second] = p.first;
return *this;
}
Insert_iterator&
operator*() { return *this; }
Insert_iterator
operator++(int) { return *this; }
};
struct Visitor
{
typedef std::unordered_map<face_descriptor,face_descriptor> Container;
Container& container;
face_descriptor qfd;
Visitor(Container& container)
: container(container)
{}
void before_subface_creations(face_descriptor fd)
{
std::cout << "split : " << fd << " into:" << std::endl;
Container::iterator it = container.find(fd);
qfd = it->second;
container.erase(it);
}
void after_subface_created(face_descriptor fd)
{
std::cout << " " << fd;
container[fd]=qfd;
}
void after_subface_creations()
{
std::cout << std::endl;
}
};
int main(int argc, char* argv[])
{
const std::string filename = (argc > 1) ? argv[1] : CGAL::data_file_path("meshes/P.off");
std::ifstream input(filename);
Surface_mesh mesh;
if (!input || !(input >> mesh) || mesh.is_empty())
{
std::cerr << "Not a valid off file." << std::endl;
return 1;
}
std::unordered_map<face_descriptor,face_descriptor> t2q;
Surface_mesh copy;
CGAL::copy_face_graph(mesh, copy, CGAL::parameters::face_to_face_output_iterator(Insert_iterator(t2q)));
Visitor v(t2q);
CGAL::parameters::visitor(v));
for(std::unordered_map<face_descriptor,face_descriptor>::iterator it = t2q.begin(); it != t2q.end(); ++it){
std::cout << it->first << " " << it->second << std::endl;
}
return 0;
}