Mesh_3/mesh_3D_image_variable_size.cpp

#define CGAL_MESH_3_VERBOSE

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>

#include <CGAL/Mesh_triangulation_3.h>
#include <CGAL/Mesh_complex_3_in_triangulation_3.h>
#include <CGAL/Mesh_criteria_3.h>
#include <CGAL/Mesh_constant_domain_field_3.h>

#include <CGAL/Labeled_mesh_domain_3.h>
#include <CGAL/make_mesh_3.h>
#include <CGAL/Image_3.h>

// Domain
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Labeled_mesh_domain_3<K> 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;
typedef CGAL::Mesh_constant_domain_field_3<Mesh_domain::R,
                                           Mesh_domain::Index> Sizing_field;

// To avoid verbose function and named parameters call
using namespace CGAL::parameters;

int main(int argc, char* argv[])
{
  const char* fname = (argc>1)?argv[1]:"data/liver.inr.gz";
  // 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);

  // Sizing field: set global size to 8 and kidney size (label 127) to 3
  double kidney_size = 3.;
  int volume_dimension = 3;
  Sizing_field size(8);
  size.set_size(kidney_size, volume_dimension, 
                domain.index_from_subdomain_index(127));
  
  // Mesh criteria
  Mesh_criteria criteria(facet_angle=30, facet_size=6, facet_distance=2,
                         cell_radius_edge_ratio=3, cell_size=size);

  // 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;
}