Polygon_mesh_processing/polyhedral_envelope_mesh_containment.cpp

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Polyhedral_envelope.h>
#include <CGAL/Polygon_mesh_processing/remesh.h>
#include <CGAL/Surface_mesh.h>

#include <fstream>

namespace PMP = CGAL::Polygon_mesh_processing;

int main(int argc, char* argv[])
{
  typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
  typedef Kernel::Point_3 Point_3;
  typedef CGAL::Surface_mesh<Point_3> Surface_mesh;

  typedef CGAL::Polyhedral_envelope<Kernel> Envelope;

  std::ifstream in((argc>1) ? argv[1] : "data/blobby.off");
  Surface_mesh tmesh;
  in >> tmesh;

  // remesh the input using the longest edge size as target edge length
  Surface_mesh query = tmesh;
  Surface_mesh::Edge_iterator longest_edge_it =
    std::max_element(edges(query).begin(), edges(query).end(),
                     [&query](Surface_mesh::Edge_index e1, Surface_mesh::Edge_index e2)
                     {
                        return PMP::edge_length(halfedge(e1, query), query) <
                               PMP::edge_length(halfedge(e2, query), query);
                     });
  PMP::isotropic_remeshing(faces(tmesh), PMP::edge_length(halfedge(*longest_edge_it, query), query), query);

  // construct the polyhedral envelope
  const double eps = (argc>2) ? std::stod(std::string(argv[2])) : 0.01;
  Envelope envelope(tmesh, eps);

  // check is the remeshed version is inside the polyhedral envelope of the input mesh
  if ( envelope(query) )
    std::cout << "Remeshing is inside the polyhedral envelope\n";
  else
    std::cout << "Remeshing is not inside the polyhedral envelope\n";

  std::ofstream("remeshed.off") << query;

  return 0;
}