Mesh_3/mesh_3D_image_with_features.cpp

#include <vector>
#include <iostream>
 
#include <CGAL/Mesh_triangulation_3.h>
#include <CGAL/Mesh_complex_3_in_triangulation_3.h>
#include <CGAL/Mesh_criteria_3.h>
 
#include <CGAL/make_mesh_3.h>
#include <CGAL/Image_3.h>
 
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Mesh_domain_with_polyline_features_3.h>
#include <CGAL/Labeled_mesh_domain_3.h>
 
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Labeled_mesh_domain_3<K> Image_domain;
typedef CGAL::Mesh_domain_with_polyline_features_3<Image_domain> Mesh_domain;
 
#ifdef CGAL_CONCURRENT_MESH_3
typedef CGAL::Parallel_tag Concurrency_tag;
#else
typedef CGAL::Sequential_tag Concurrency_tag;
#endif
 
// Triangulation
typedef CGAL::Mesh_triangulation_3<Mesh_domain,CGAL::Default,Concurrency_tag>::type Tr;
 
typedef CGAL::Mesh_complex_3_in_triangulation_3<Tr> C3t3;
 
// Criteria
typedef CGAL::Mesh_criteria_3<Tr> Mesh_criteria;
 
// To avoid verbose function and named parameters call
using namespace CGAL::parameters;
 
#include "read_polylines.h"
#include <CGAL/Mesh_3/polylines_to_protect.h> // undocumented header
 
// Protect the intersection of the object with the box of the image,
// by declaring 1D-features. Note that `CGAL::polylines_to_protect` is
// not documented.
bool add_1D_features(const CGAL::Image_3& image,
                     Mesh_domain& domain,
                     const char* lines_fname)
{
  typedef K::Point_3 Point_3;
  typedef unsigned char Word_type;
 
  std::vector<std::vector<Point_3> > features_inside;
  if(!read_polylines(lines_fname, features_inside)) // see file "read_polylines.h"
  {
    std::cerr << "Error: Cannot read file " <<  lines_fname << std::endl;
    return false;
  }
 
  std::vector<std::vector<Point_3> > polylines_on_bbox;
  CGAL::polylines_to_protect<Point_3, Word_type>(image, polylines_on_bbox,
                                                 features_inside.begin(),
                                                 features_inside.end());
 
  domain.add_features(polylines_on_bbox.begin(), polylines_on_bbox.end());
 
  // It is very important that the polylines from the file `lines_fname`
  // contain only polylines in the inside of the box of the image.
  domain.add_features(features_inside.begin(), features_inside.end());
  return true;
}
 
int main(int argc, char* argv[])
{
  const char* fname = (argc>1)?argv[1]:"data/420.inr";
  // Loads image
  CGAL::Image_3 image;
  if(!image.read(fname)){
    std::cerr << "Error: Cannot read file " <<  fname << std::endl;
    return EXIT_FAILURE;
  }
 
  // Domain
  Mesh_domain domain = Mesh_domain::create_labeled_image_mesh_domain(image);
 
  const char* lines_fname = (argc>2)?argv[2]:"data/420.polylines.txt";
 
  if(!add_1D_features(image, domain, lines_fname)) {
    return EXIT_FAILURE;
  }
 
  Mesh_criteria criteria(edge_size=6,
                         facet_angle=30, facet_size=6, facet_distance=4,
                         cell_radius_edge_ratio=3, cell_size=8);
 
  // Meshing
  C3t3 c3t3 = CGAL::make_mesh_3<C3t3>(domain, criteria);
 
  // Output
  std::ofstream medit_file("out.mesh");
  c3t3.output_to_medit(medit_file);
 
  return 0;
}