CGAL 6.1 - 3D Mesh Generation

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Mesh_3/mesh_3D_image_with_custom_initialization.cpp
#include "random_labeled_image.h"
#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/make_mesh_3.h>
#include <CGAL/Image_3.h>
#include <CGAL/SMDS_3/Dump_c3t3.h>
#include <CGAL/Mesh_3/Detect_features_on_image_bbox.h>
// Domain
using K = CGAL::Exact_predicates_inexact_constructions_kernel;
using Image_domain = CGAL::Labeled_mesh_domain_3<K>;
using Mesh_domain = CGAL::Mesh_domain_with_polyline_features_3<Image_domain>;
#ifdef CGAL_CONCURRENT_MESH_3
using Concurrency_tag = CGAL::Parallel_tag;
#else
using Concurrency_tag = CGAL::Sequential_tag;
#endif
// Triangulation
using Tr = CGAL::Mesh_triangulation_3<Mesh_domain, CGAL::Default, Concurrency_tag>::type;
using C3t3 = CGAL::Mesh_complex_3_in_triangulation_3<Tr>;
// Criteria
using Mesh_criteria = CGAL::Mesh_criteria_3<Tr>;
namespace params = CGAL::parameters;
int main()
{
const std::string fname = CGAL::data_file_path("images/420.inr");
// 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
, params::features_detector(CGAL::Mesh_3::Detect_features_on_image_bbox()));
// Mesh criteria
const double edge_size = 3;
Mesh_criteria criteria(params::edge_size(edge_size)
.facet_angle(30).facet_size(3).facet_distance(1)
.cell_radius_edge_ratio(3).cell_size(3));
// custom_initial_points_generator will put points on the mesh for initialization.
// Those points are objects of type std::tuple<Weighted_point_3, int, Index>.
// Weighted_point_3 is the point's position and weight,
// int is the dimension of the minimal dimension subcomplex on which the point lies,
// Index is the underlying subcomplex index.
auto custom_initial_points_generator = [&](auto pts_out_iterator, int) {
using Point_3 = K::Point_3;
using Weighted_point_3 = K::Weighted_point_3;
using Index = Mesh_domain::Index;
using Point_dim_index = std::tuple<Weighted_point_3, int, Index>;
Point_3 a{0.0, 50.0, 66.66};
Point_3 b{100.0, 50.0, 66.66};
// Add points along the segment [a, b]
double dist_ab = CGAL::sqrt(CGAL::squared_distance(a, b));
int nb = static_cast<int>(std::floor(dist_ab / edge_size));
auto vector = (b - a) / static_cast<double>(nb);
Point_3 p = a;
for(int i = 0; i < nb; ++i) {
*pts_out_iterator++ = Point_dim_index{Weighted_point_3{p}, 1, Index(1)};
p += vector;
}
return pts_out_iterator;
};
C3t3 c3t3 = CGAL::make_mesh_3<C3t3>(domain, criteria,
params::initial_points_generator(custom_initial_points_generator));
// Output
CGAL::dump_c3t3(c3t3, "out");
return 0;
}
CGAL::Exact_predicates_inexact_constructions_kernel
CGAL::Image_3
The class Image_3 is a C++ wrapper around the InrImage library.
Definition: Image_3.h:11
CGAL::Image_3::read
bool read(const char *file)
Open a 3D image file.
CGAL::Labeled_mesh_domain_3
The class Labeled_mesh_domain_3 implements indexed domains.
Definition: Labeled_mesh_domain_3.h:354
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:535
Index
unspecified_type
CGAL::sqrt
NT sqrt(const NT &x)
CGAL::squared_distance
Kernel::FT squared_distance(Type1< Kernel > obj1, Type2< Kernel > obj2)
CGAL::parameters
CGAL::Mesh_3::Detect_features_on_image_bbox
Functor for feature detection in labeled images.
Definition: Detect_features_on_image_bbox.h:76
CGAL::Parallel_tag
CGAL::Sequential_tag