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#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/IO/write_MEDIT.h>
#include <CGAL/Surface_mesh/Surface_mesh.h>
#include <CGAL/Polygon_mesh_processing/self_intersections.h>
#include <CGAL/Polygon_mesh_processing/autorefinement.h>
#include <CGAL/Polygon_mesh_processing/triangulate_faces.h>
#include <CGAL/boost/graph/copy_face_graph.h>
#include <CGAL/make_conforming_constrained_Delaunay_triangulation_3.h>
#include <CGAL/draw_constrained_triangulation_3.h>
using K = CGAL::Exact_predicates_inexact_constructions_kernel;
using Point = K::Point_3;
using Surface_mesh = CGAL::Surface_mesh<Point>;
namespace PMP = CGAL::Polygon_mesh_processing;
int main(int argc, char* argv[])
{
const auto filename = (argc > 1) ? argv[1]
: CGAL::data_file_path("meshes/mpi_and_sphere.off");
CGAL::Surface_mesh<K::Point_3> mesh;
if(!CGAL::IO::read_polygon_mesh(filename, mesh)) {
std::cerr << "Error: cannot read file " << filename << std::endl;
return EXIT_FAILURE;
}
std::cout << "Number of facets in " << filename << ": "
<< mesh.number_of_faces() << "\n";
// Check if the mesh is a triangle mesh
bool triangle_mesh = CGAL::is_triangle_mesh(mesh);
if(!triangle_mesh)
{
std::cout << "Mesh is not a triangle mesh, triangulate faces"
<< " to check self-intersections...\n";
CGAL::Surface_mesh<K::Point_3> trimesh;
CGAL::copy_face_graph(mesh, trimesh);
PMP::triangulate_faces(trimesh);
if(PMP::does_self_intersect(trimesh))
{
std::cout << "Mesh self-intersects, let's keep the triangulated version"
<< " for future autorefinement\n";
CGAL::copy_face_graph(trimesh, mesh);
mesh = std::move(trimesh);
triangle_mesh = true;
}
}
CGAL::Conforming_constrained_Delaunay_triangulation_3<K> ccdt;
if(triangle_mesh && PMP::does_self_intersect(mesh))
{
std::cout << "Mesh is a self-intersecting triangle mesh, perform autorefinement...\n";
// use a polygon soup as container as the output will most likely be non-manifold
std::vector<K::Point_3> points;
std::vector<std::vector<std::size_t>> polygons;
PMP::polygon_mesh_to_polygon_soup(mesh, points, polygons);
PMP::autorefine_triangle_soup(points, polygons);
std::cout << "Number of facets after preprocessing: "
<< polygons.size() << "\n";
if(PMP::does_polygon_soup_self_intersect(points, polygons))
{
std::cerr << "Error: mesh still self-intersects after autorefine\n";
return EXIT_FAILURE;
}
ccdt = CGAL::make_conforming_constrained_Delaunay_triangulation_3(points, polygons);
}
else
{
std::cout << "Number of facets after preprocessing: "
<< mesh.number_of_faces() << "\n";
ccdt = CGAL::make_conforming_constrained_Delaunay_triangulation_3(mesh);
}
std::cout << "Number of constrained facets in the CDT: "
<< ccdt.number_of_constrained_facets() << '\n';
std::ofstream ofs(argc > 2 ? argv[2] : "out.mesh");
ofs.precision(17);
CGAL::IO::write_MEDIT(ofs, ccdt);
CGAL::draw(ccdt);
return EXIT_SUCCESS;
}
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