CGAL 5.2 - Polygon Mesh Processing
Polygon_mesh_processing/manifoldness_repair_example.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/boost/graph/iterator.h>
#include <CGAL/Polygon_mesh_processing/repair.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/IO/OFF_reader.h>
#include <fstream>
#include <iostream>
#include <iterator>
#include <vector>
namespace NP = CGAL::parameters;
typedef boost::graph_traits<Mesh>::vertex_descriptor vertex_descriptor;
typedef boost::graph_traits<Mesh>::halfedge_descriptor halfedge_descriptor;
void merge_vertices(vertex_descriptor v_keep, vertex_descriptor v_rm, Mesh& mesh)
{
std::cout << "merging vertices " << v_keep << " and " << v_rm << std::endl;
for(halfedge_descriptor h : CGAL::halfedges_around_target(v_rm, mesh)){
set_target(h, v_keep, mesh); // to ensure that no halfedge points at the deleted vertex
}
remove_vertex(v_rm, mesh);
}
int main(int argc, char* argv[])
{
const char* filename = (argc > 1) ? argv[1] : "data/blobby.off";
std::ifstream input(filename);
Mesh mesh;
if(!input || !(input >> mesh) || num_vertices(mesh) == 0)
{
std::cerr << filename << " is not a valid off file." << std::endl;
return EXIT_FAILURE;
}
// Artificially create non-manifoldness for the sake of the example by merging some vertices
vertex_descriptor v0 = *(vertices(mesh).begin());
vertex_descriptor v1 = *(--(vertices(mesh).end()));
merge_vertices(v0, v1, mesh);
// Count non manifold vertices
int counter = 0;
for(vertex_descriptor v : vertices(mesh))
{
{
std::cout << "vertex " << v << " is non-manifold" << std::endl;
++counter;
}
}
std::cout << counter << " non-manifold occurrence(s)" << std::endl;
// Fix manifoldness by splitting non-manifold vertices
std::vector<std::vector<vertex_descriptor> > duplicated_vertices;
std::size_t new_vertices_nb = PMP::duplicate_non_manifold_vertices(mesh,
NP::output_iterator(
std::back_inserter(duplicated_vertices)));
std::cout << new_vertices_nb << " vertices have been added to fix mesh manifoldness" << std::endl;
for(std::size_t i=0; i<duplicated_vertices.size(); ++i)
{
std::cout << "Non-manifold vertex " << duplicated_vertices[i].front() << " was fixed by creating";
for(std::size_t j=1; j<duplicated_vertices[i].size(); ++j)
std::cout << " " << duplicated_vertices[i][j];
std::cout << std::endl;
}
return EXIT_SUCCESS;
}