User Manual

Author

Laurent Rineau

This chapter describes the ...

Todo:

Explain what is a CDT. Why a given input, like a polyhedron, might not admit a constrained Delaunay triangulation. Explain "conforming to the faces of a polygon mesh".

Definitions

Section on definitions here ...

Examples

First Example

The following example shows ...

File Constrained_triangulation_3/conforming_constrained_Delaunay_triangulation_3.cpp

#include <CGAL/make_conforming_constrained_Delaunay_triangulation_3.h>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/draw_triangulation_3.h>
 
#include <algorithm>
 
using K = CGAL::Exact_predicates_inexact_constructions_kernel;
 
int main(int argc, char* argv[])
{
  CGAL::Surface_mesh<K::Point_3> mesh;
 
  auto filename = (argc > 1) ? argv[1] : CGAL::data_file_path("meshes/mpi.off");
  std::ifstream in(filename);
  if(!in || !CGAL::IO::read_OFF(in, mesh)) {
    std::cerr << "Error: cannot read file " << filename << std::endl;
    return EXIT_FAILURE;
  }
 
  std::cout << "Read " << mesh.number_of_vertices() << " vertices and "
            << mesh.number_of_faces() << " faces" << std::endl;
 
  auto ccdt = CGAL::make_conforming_constrained_Delaunay_triangulation_3(mesh);
 
  std::cout << "Number of vertices in the CDT: "
            << ccdt.triangulation().number_of_vertices() << '\n'
            << "Number of constrained facets in the CDT: "
            << ccdt.number_of_constrained_facets() << '\n';
 
  CGAL::draw(ccdt.triangulation());
}

or from a polygon soup ...

File Constrained_triangulation_3/conforming_constrained_Delaunay_triangulation_3_from_soup.cpp

#include <CGAL/make_conforming_constrained_Delaunay_triangulation_3.h>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <vector>
#include <CGAL/draw_triangulation_3.h>
 
#include <algorithm>
 
using K = CGAL::Exact_predicates_inexact_constructions_kernel;
 
int main(int argc, char* argv[])
{
  std::vector<K::Point_3> points;
  std::vector<std::vector<std::size_t>> polygons;
 
  auto filename = (argc > 1) ? argv[1] : CGAL::data_file_path("meshes/cubes.off");
  std::ifstream in(filename);
  if(!in || !CGAL::IO::read_OFF(in, points, polygons)) {
    std::cerr << "Error: cannot read file " << filename << std::endl;
    return EXIT_FAILURE;
  }
 
  std::cout << "Read " << points.size() << " vertices and "
            << polygons.size() << " polygons" << std::endl;
 
  auto ccdt = CGAL::make_conforming_constrained_Delaunay_triangulation_3(points, polygons);
 
  std::cout << "Number of vertices in the CDT: "
            << ccdt.triangulation().number_of_vertices() << '\n'
            << "Number of constrained facets in the CDT: "
            << ccdt.number_of_constrained_facets() << '\n';
 
  CGAL::draw(ccdt.triangulation());
}