CGAL 4.7 - 3D Mesh Generation: Mesh_3/mesh_implicit_sphere_variable_size.cpp

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CGAL 4.7 - 3D Mesh Generation

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Mesh_3/mesh_implicit_sphere_variable_size.cpp
#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/Implicit_mesh_domain_3.h>
#include <CGAL/make_mesh_3.h>
// Domain
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef K::FT FT;
typedef K::Point_3 Point;
typedef FT (Function)(const Point&);
typedef CGAL::Implicit_mesh_domain_3<Function,K> Mesh_domain;
// Triangulation
#ifdef CGAL_CONCURRENT_MESH_3
typedef CGAL::Mesh_triangulation_3<
Mesh_domain,
CGAL::Kernel_traits<Mesh_domain>::Kernel, // Same as sequential
CGAL::Parallel_tag // Tag to activate parallelism
>::type Tr;
#else
typedef CGAL::Mesh_triangulation_3<Mesh_domain>::type Tr;
#endif
typedef CGAL::Mesh_complex_3_in_triangulation_3<Tr> C3t3;
// Criteria
typedef CGAL::Mesh_criteria_3<Tr> Mesh_criteria;
// Sizing field
struct Spherical_sizing_field
{
typedef ::FT FT;
typedef Point Point_3;
typedef Mesh_domain::Index Index;
FT operator()(const Point_3& p, const int, const Index&) const
{
FT sq_d_to_origin = CGAL::squared_distance(p, Point( CGAL::ORIGIN));
return CGAL::abs( CGAL::sqrt(sq_d_to_origin)-0.5 ) / 5. + 0.025;
}
};
// To avoid verbose function and named parameters call
using namespace CGAL::parameters;
// Function
FT sphere_function (const Point& p)
{ return CGAL::squared_distance(p, Point(CGAL::ORIGIN))-1; }
int main()
{
// Domain (Warning: Sphere_3 constructor uses squared radius !)
Mesh_domain domain(sphere_function,
K::Sphere_3(CGAL::ORIGIN, 2.));
// Mesh criteria
Spherical_sizing_field size;
Mesh_criteria criteria(facet_angle=30, facet_size=0.1, facet_distance=0.025,
cell_radius_edge_ratio=2, cell_size=size);
// Mesh generation
C3t3 c3t3 = CGAL::make_mesh_3<C3t3>(domain, criteria, no_exude(), no_perturb());
// Output
std::ofstream medit_file("out.mesh");
c3t3.output_to_medit(medit_file);
return 0;
}