\( \newcommand{\E}{\mathrm{E}} \) \( \newcommand{\A}{\mathrm{A}} \) \( \newcommand{\R}{\mathrm{R}} \) \( \newcommand{\N}{\mathrm{N}} \) \( \newcommand{\Q}{\mathrm{Q}} \) \( \newcommand{\Z}{\mathrm{Z}} \) \( \def\ccSum #1#2#3{ \sum_{#1}^{#2}{#3} } \def\ccProd #1#2#3{ \sum_{#1}^{#2}{#3} }\)
CGAL 4.13 - 3D Mesh Generation
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::Labeled_mesh_domain_3<K> Image_domain;
#ifdef CGAL_CONCURRENT_MESH_3
typedef CGAL::Parallel_tag Concurrency_tag;
#else
typedef CGAL::Sequential_tag Concurrency_tag;
#endif
// Triangulation
// 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
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;
}