CGAL 6.2 - 3D Mesh Generation

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Mesh_3/mesh_hybrid_mesh_domain.cpp
// #define CGAL_MESH_3_PROTECTION_DEBUG 1
// #define CGAL_MESH_3_VERBOSE 1
#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/Labeled_mesh_domain_3.h>
#include <CGAL/Polyhedron_3.h>
#include <CGAL/Polyhedral_mesh_domain_3.h>
#include <CGAL/Mesh_domain_with_polyline_features_3.h>
#include <CGAL/make_mesh_3.h>
// Output
#include <CGAL/SMDS_3/Dump_c3t3.h>
// Read 1D features from input file
#include "read_polylines.h"
// Sphere Domain
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Labeled_mesh_domain_3<K> Implicit_domain;
// Polyhedral Domain
typedef CGAL::Polyhedron_3<K> Polyhedron;
typedef CGAL::Polyhedral_mesh_domain_3<Polyhedron, K> Polyhedron_domain;
class Hybrid_domain
{
const Implicit_domain& implicit_domain;
const Polyhedron_domain& polyhedron_domain;
public:
Hybrid_domain(const Implicit_domain& implicit_domain,
const Polyhedron_domain& polyhedron_domain)
: implicit_domain(implicit_domain)
, polyhedron_domain(polyhedron_domain)
{}
// types required by the `MeshDomain_3` concept
typedef int Surface_patch_index;
typedef int Subdomain_index;
typedef int Index;
typedef K R;
typedef K::Point_3 Point_3;
typedef std::tuple<Point_3, Index, int> Intersection;
CGAL::Bbox_3 bbox() const {
return implicit_domain.bbox() + polyhedron_domain.bbox();
}
struct Construct_initial_points
{
Construct_initial_points(const Hybrid_domain& domain)
: r_domain_(domain) {}
template<class OutputIterator>
OutputIterator operator()(OutputIterator pts, const int n = 20) const
{
//construct initial points on implicit domain
typedef Implicit_domain::Index Implicit_Index;
std::vector<std::pair<Point_3,
Implicit_Index> > implicit_points_vector;
Implicit_domain::Construct_initial_points cstr_implicit_initial_points =
r_domain_.implicit_domain.construct_initial_points_object();
cstr_implicit_initial_points(std::back_inserter(implicit_points_vector),
n/2);
for(std::size_t i = 0, end = implicit_points_vector.size(); i<end; ++i) {
*pts++ = std::make_pair(implicit_points_vector[i].first, 2);
}
//construct initial points on polyhedral domain
typedef Polyhedron_domain::Index Polyhedron_Index;
std::vector<std::pair<Point_3,
Polyhedron_Index> > polyhedron_points_vector;
Polyhedron_domain::Construct_initial_points cstr_polyhedron_initial_points =
r_domain_.polyhedron_domain.construct_initial_points_object();
cstr_polyhedron_initial_points(std::back_inserter(polyhedron_points_vector),
n/2);
for(std::size_t i = 0, end = polyhedron_points_vector.size(); i<end; ++i) {
*pts++ = std::make_pair(polyhedron_points_vector[i].first, 1);
}
return pts;
}
private:
const Hybrid_domain& r_domain_;
}; // end Construct_initial_points_object
Construct_initial_points construct_initial_points_object() const
{
return Construct_initial_points(*this);
}
struct Is_in_domain
{
Is_in_domain(const Hybrid_domain& domain) : r_domain_(domain) {}
std::optional<Subdomain_index> operator()(const K::Point_3& p) const
{
std::optional<Subdomain_index> subdomain_index =
r_domain_.implicit_domain.is_in_domain_object()(p);
if(subdomain_index) return 2;
else return r_domain_.polyhedron_domain.is_in_domain_object()(p);
}
private:
const Hybrid_domain& r_domain_;
};
Is_in_domain is_in_domain_object() const { return Is_in_domain(*this); }
struct Construct_intersection
{
Construct_intersection(const Hybrid_domain& domain)
: r_domain_(domain) {}
template <typename Query>
Intersection operator()(const Query& query) const
{
using boost::get;
//intersection with implicit domain
Implicit_domain::Intersection implicit_inter =
r_domain_.implicit_domain.construct_intersection_object()(query);
//if found, return it
if(get<2>(implicit_inter) != 0) {
return Intersection(get<0>(implicit_inter), 2, get<2>(implicit_inter));
}
//intersection with polyhedral domain
Polyhedron_domain::Intersection polyhedron_inter =
r_domain_.polyhedron_domain.construct_intersection_object()(query);
//if found, return it
if(get<2>(polyhedron_inter) != 0) {
const Point_3 inter_point = get<0>(polyhedron_inter);
if(!r_domain_.implicit_domain.is_in_domain_object()(inter_point)) {
return Intersection(inter_point, 1, get<2>(polyhedron_inter));
}
}
//no intersection found
return Intersection();
}
private:
const Hybrid_domain& r_domain_;
}; // end Construct_intersection
Construct_intersection construct_intersection_object() const
{
return Construct_intersection(*this);
}
//Index types converters
Index index_from_surface_patch_index(const Surface_patch_index& index) const
{ return index; }
Index index_from_subdomain_index(const Subdomain_index& index) const
{ return index; }
Surface_patch_index surface_patch_index(const Index& index) const
{ return index; }
Subdomain_index subdomain_index(const Index& index) const
{ return index; }
}; // end class Hybrid_domain
typedef CGAL::Mesh_domain_with_polyline_features_3<Hybrid_domain> Domain;
// Triangulation
typedef CGAL::Mesh_triangulation_3<Domain, K>::type Tr;
typedef CGAL::Mesh_complex_3_in_triangulation_3<Tr> C3t3;
// Criteria
typedef CGAL::Mesh_criteria_3<Tr> Mesh_criteria;
typedef Mesh_criteria::Edge_criteria Edge_criteria;
typedef Mesh_criteria::Facet_criteria Facet_criteria;
typedef Mesh_criteria::Cell_criteria Cell_criteria;
// Function
typedef K::FT FT;
typedef K::Point_3 Point;
FT sphere_centered_at_111 (const Point& p)
{
const FT dx=p.x()-1;
const FT dy=p.y()-1;
const FT dz=p.z()-1;
return dx*dx+dy*dy+dz*dz-1;
}
namespace params = CGAL::parameters;
int main()
{
const std::string fname = CGAL::data_file_path("meshes/cube.off");
// Create input polyhedron
Polyhedron polyhedron;
std::ifstream input(fname);
input >> polyhedron;
if(input.bad()){
std::cerr << "Error: Cannot read file " << fname << std::endl;
return EXIT_FAILURE;
}
input.close();
// Polyhedra domain
Polyhedron_domain polyhedron_domain(polyhedron);
// Implicit domain
// - the first argument is the function pointer
// - the second argument is a bounding sphere of the domain
// (Warning: Sphere_3 constructor uses square radius !)
Implicit_domain sphere_domain =
Implicit_domain::create_implicit_mesh_domain(sphere_centered_at_111,
K::Sphere_3(K::Point_3(1, 1, 1), K::FT(2)));
Domain domain(sphere_domain, polyhedron_domain);
// Read polyline features
const char* lines_fname = "data/hybrid_example.polylines.txt";
std::vector<std::vector<Point> > featured_curves;
if (!read_polylines(lines_fname, featured_curves))
{ // see file "read_polylines.h"
std::cerr << "Error: Cannot read file " << lines_fname << std::endl;
return EXIT_FAILURE;
}
// Add features for protection
domain.add_features(featured_curves.begin(), featured_curves.end());
// Criteria
Edge_criteria edge_criteria(0.08);
Facet_criteria facet_criteria(30, 0.08, 0.025); // angle, size, approximation
Cell_criteria cell_criteria(2, 0.1); // radius-edge ratio, size
Mesh_criteria criteria(edge_criteria, facet_criteria, cell_criteria);
// Mesh generation (without optimization)
C3t3 c3t3 = CGAL::make_mesh_3<C3t3>(domain, criteria,
params::no_perturb().no_exude());
// Output
dump_c3t3(c3t3, "out");
return EXIT_SUCCESS;
}
CGAL::Bbox_3
CGAL::Exact_predicates_inexact_constructions_kernel
CGAL::Labeled_mesh_domain_3
The class Labeled_mesh_domain_3 implements indexed domains.
Definition: Labeled_mesh_domain_3.h:53
CGAL::Mesh_complex_3_in_triangulation_3
CGAL::Mesh_criteria_3
The class gathers the refinement criteria for mesh tetrahedra and surface facets where surface facets...
Definition: Mesh_criteria_3.h:186
CGAL::Mesh_domain_with_polyline_features_3
The class Mesh_domain_with_polyline_features_3 enables the user to add some 0- and 1-dimensional feat...
Definition: Mesh_domain_with_polyline_features_3.h:144
CGAL::Polyhedral_mesh_domain_3
The class Polyhedral_mesh_domain_3 implements a domain defined by a simplicial polyhedral surface.
Definition: Polyhedral_mesh_domain_3.h:153
CGAL::Polyhedron_3
Index
OutputIterator
unspecified_type
CGAL::parameters::no_exude
unspecified_type no_exude()
The function parameters::no_exude() enables the user to tell the mesh generation functions make_mesh_...
CGAL::parameters