CGAL 5.6.1 - 3D Periodic Mesh Generation
Periodic_3_mesh_3/mesh_implicit_multi_domain.cpp
#include <CGAL/Periodic_3_mesh_3/config.h>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/make_periodic_3_mesh_3.h>
#include <CGAL/Periodic_3_mesh_3/IO/File_medit.h>
#include <CGAL/Periodic_3_mesh_triangulation_3.h>
#include <CGAL/Periodic_3_function_wrapper.h>
#include <CGAL/Implicit_to_labeling_function_wrapper.h>
#include <CGAL/Labeled_mesh_domain_3.h>
#include <CGAL/Mesh_complex_3_in_triangulation_3.h>
#include <CGAL/Mesh_criteria_3.h>
#include <CGAL/number_type_config.h> // CGAL_PI
#include <cmath>
#include <fstream>
#include <iostream>
#include <string>
#include <vector>
// Kernel
typedef K::FT FT;
typedef K::Point_3 Point;
typedef K::Iso_cuboid_3 Iso_cuboid;
// Domain
typedef FT (*Function)(const Point&);
// This wrapper is needed to make 'sphere_function' periodic.
typedef CGAL::Labeled_mesh_domain_3<K> Periodic_mesh_domain;
// Triangulation
typedef CGAL::Mesh_complex_3_in_triangulation_3<Tr> C3t3;
// Criteria
typedef CGAL::Mesh_criteria_3<Tr> Periodic_mesh_criteria;
// To avoid verbose function and named parameters call
namespace params = CGAL::parameters;
// Implicit functions
FT sphere_function(const Point& p)
{
return CGAL::squared_distance(p, Point(0.5, 0.5, 0.5)) - 0.15;
}
FT schwarz_p(const Point& p)
{
const FT x2 = std::cos( p.x() * 2 * CGAL_PI ),
y2 = std::cos( p.y() * 2 * CGAL_PI ),
z2 = std::cos( p.z() * 2 * CGAL_PI );
return x2 + y2 + z2;
}
int main(int argc, char** argv)
{
int domain_size = (argc > 1) ? atoi(argv[1]) : 1;
int number_of_copies_in_output = (argc > 2) ? atoi(argv[2]) : 4; // can be 1, 2, 4, or 8
Iso_cuboid canonical_cube(0, 0, 0, domain_size, domain_size, domain_size);
std::vector<Periodic_function> funcs;
funcs.push_back(Periodic_function(&schwarz_p, canonical_cube));
funcs.push_back(Periodic_function(&sphere_function, canonical_cube));
// The vector of vectors of sign is passed as a vector of strings (since a string
// is a vector of chars)
std::vector<std::string> vps;
vps.push_back("--");
vps.push_back("-+");
Multi_domain_wrapper multi_domain_function(funcs, vps);
Periodic_mesh_domain domain(multi_domain_function, canonical_cube);
Periodic_mesh_criteria criteria(params::facet_angle(30)
.facet_size(0.04)
.facet_distance(0.025)
.cell_radius_edge_ratio(2.)
.cell_size(0.04));
// Mesh generation
C3t3 c3t3 = CGAL::make_periodic_3_mesh_3<C3t3>(domain, criteria);
// Output
std::ofstream medit_file("output_multi_domain.mesh");
CGAL::IO::output_periodic_mesh_to_medit<C3t3>(medit_file, c3t3, number_of_copies_in_output,
false /*do not associate different colors to each copy*/,
false /*do not rebind*/, true /*show patches*/);
std::cout << "EXIT SUCCESS" << std::endl;
return 0;
}