C++ Traits::compute_squared_distance_3_object方法代码示例

void test_simple_saddle_vertex_mesh()
{
  typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
  typedef CGAL::Polyhedron_3<Kernel, CGAL::Polyhedron_items_with_id_3> Polyhedron_3;
  typedef CGAL::Surface_mesh_shortest_path_traits<Kernel, Polyhedron_3> Traits;
  typedef Traits::Barycentric_coordinate Barycentric_coordinate;
  typedef Traits::FT FT;
  typedef Traits::Point_3 Point_3;
  typedef Traits::Point_2 Point_2;
  typedef Traits::Triangle_3 Triangle_3;
  typedef Traits::Triangle_2 Triangle_2;
  typedef Traits::Segment_2 Segment_2;
  typedef boost::graph_traits<Polyhedron_3> Graph_traits;
  typedef Graph_traits::vertex_descriptor vertex_descriptor;
  typedef Graph_traits::vertex_iterator vertex_iterator;
  typedef Graph_traits::halfedge_descriptor halfedge_descriptor;
  typedef Graph_traits::face_descriptor face_descriptor;
  typedef CGAL::Surface_mesh_shortest_path<Traits> Surface_mesh_shortest_path;
  typedef boost::property_map<Polyhedron_3, CGAL::vertex_point_t>::type VPM;

  Traits traits;

  Traits::Compute_squared_distance_3 compute_squared_distance_3(traits.compute_squared_distance_3_object());
  Traits::Compute_squared_distance_2 compute_squared_distance_2(traits.compute_squared_distance_2_object());
  Traits::Construct_triangle_3_along_segment_2_flattening flatten_triangle_3_along_segment_2(traits.construct_triangle_3_along_segment_2_flattening_object());
  Traits::Construct_barycentric_coordinate construct_barycentric_coordinate(traits.construct_barycentric_coordinate_object());

  std::ifstream inFile("data/saddle_vertex_mesh.off");

  Polyhedron_3 P;

  inFile >> P;

  inFile.close();

  CGAL::set_halfedgeds_items_id(P);

  vertex_iterator startVertex;
  vertex_iterator endVertex;
  boost::tie(startVertex, endVertex) = CGAL::vertices(P);

  vertex_iterator currentVertex = startVertex;

  ++currentVertex;
  vertex_descriptor rootSearchVertex = *currentVertex;

  face_descriptor currentFace = CGAL::face(CGAL::halfedge(rootSearchVertex, P), P);
  size_t vertexIndex = CGAL::test::face_vertex_index(currentFace, rootSearchVertex, P);
  Barycentric_coordinate baryCoord = construct_barycentric_coordinate(vertexIndex == 0 ? FT(1.0) : FT(0.0), vertexIndex == 1 ? FT(1.0) : FT(0.0), vertexIndex == 2 ? FT(1.0) : FT(0.0));

  Surface_mesh_shortest_path shortestPaths(P, traits);
  //shortestPaths.m_debugOutput = true;
  Surface_mesh_shortest_path::Source_point_iterator firstSourcePoint = shortestPaths.add_source_point(currentFace, baryCoord);
  shortestPaths.build_sequence_tree();

  VPM vpm = CGAL::get(CGAL::vertex_point, P);

  Point_3 vertexLocations[8];
  vertex_descriptor vertexHandles[8];

  currentVertex = startVertex;

  for (size_t i = 0; i < 8; ++i)
  {
    vertexHandles[i] = *currentVertex;
    vertexLocations[i] = vpm[*currentVertex];
    ++currentVertex;
  }

  FT distanceToBottom = CGAL::sqrt(compute_squared_distance_3(vertexLocations[1], vertexLocations[0]));
  FT largerSideLength = CGAL::sqrt(compute_squared_distance_3(vertexLocations[1], vertexLocations[2]));
  FT distanceToSaddle = CGAL::sqrt(compute_squared_distance_3(vertexLocations[1], vertexLocations[4]));
  FT shorterSideLength = CGAL::sqrt(compute_squared_distance_3(vertexLocations[4], vertexLocations[6]));

  Triangle_3 lower(vertexLocations[6], vertexLocations[4], vertexLocations[1]);
  Triangle_3 upper(vertexLocations[4], vertexLocations[6], vertexLocations[7]);

  Segment_2 base(Point_2(CGAL::ORIGIN), Point_2(shorterSideLength, FT(0.0)));

  Triangle_2 flatLower(flatten_triangle_3_along_segment_2(lower, 0, base));
  Triangle_2 flatUpper(flatten_triangle_3_along_segment_2(upper, 0, Segment_2(base[1], base[0])));

  FT distanceToApex = CGAL::sqrt(compute_squared_distance_2(flatLower[2], flatUpper[2]));

  FT expectedDistances[8] =
  {
    distanceToBottom, // a vertex of the larger tetrahedron
    FT(0.0), // the initial vertex
    largerSideLength, // a vertex of the larger tetrahedron
    largerSideLength, // a vertex of the larger tetrahedron
    distanceToSaddle,  // direct line of sight from root
    distanceToSaddle + shorterSideLength,  // around the corner from a pseudo-source (not in direct line of geodesic sight)
    distanceToSaddle, // direct line of sight from root
    distanceToApex,
  };

  currentVertex = startVertex;

  for (size_t i = 0; i < 8; ++i)
  {
//.........这里部分代码省略.........

void test_boundary_mesh()
{
  typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel;
  typedef CGAL::Polyhedron_3<Kernel, CGAL::Polyhedron_items_with_id_3> Polyhedron_3;
  typedef CGAL::Surface_mesh_shortest_path_traits<Kernel, Polyhedron_3> Traits;
  typedef Traits::Barycentric_coordinate Barycentric_coordinate;
  typedef Traits::FT FT;
  typedef Traits::Point_3 Point_3;
  typedef Traits::Triangle_3 Triangle_3;
  typedef boost::graph_traits<Polyhedron_3> Graph_traits;
  typedef Graph_traits::vertex_descriptor vertex_descriptor;
  typedef Graph_traits::vertex_iterator vertex_iterator;
  typedef Graph_traits::face_descriptor face_descriptor;
  typedef Graph_traits::face_iterator face_iterator;
  typedef CGAL::Surface_mesh_shortest_path<Traits> Surface_mesh_shortest_path;
  typedef boost::property_map<Polyhedron_3, CGAL::vertex_point_t>::type VPM;

  Traits traits;

  Traits::Construct_triangle_3_to_triangle_2_projection project_triangle_3_to_triangle_2(traits.construct_triangle_3_to_triangle_2_projection_object());
  CGAL_USE(project_triangle_3_to_triangle_2);
  Traits::Compute_squared_distance_3 compute_squared_distance_3(traits.compute_squared_distance_3_object());
  Traits::Construct_barycenter_3 construct_barycenter_3(traits.construct_barycenter_3_object());
  Traits::Construct_triangle_3_along_segment_2_flattening flatten_triangle_3_along_segment_2(traits.construct_triangle_3_along_segment_2_flattening_object());
  CGAL_USE(flatten_triangle_3_along_segment_2);
  Traits::Construct_barycentric_coordinate construct_barycentric_coordinate(traits.construct_barycentric_coordinate_object());

  struct Construct_barycenter_in_triangle_3
  {
    Traits::Construct_barycenter_3 m_cb3;

    Construct_barycenter_in_triangle_3(Traits::Construct_barycenter_3 cb3)
      : m_cb3(cb3)
    {
    }

    Point_3 operator() (const Triangle_3& t, const Barycentric_coordinate& b)
    {
      return m_cb3(t[0], b[0], t[1], b[1], t[2], b[2]);
    }
  } construct_barycenter_in_triangle_3(construct_barycenter_3);

  std::ifstream inFile("data/boundary_mesh.off");

  Polyhedron_3 P;

  inFile >> P;

  inFile.close();

  CGAL::set_halfedgeds_items_id(P);

  face_iterator startFace;
  face_iterator endFace;

  boost::tie(startFace, endFace) = CGAL::faces(P);

  vertex_iterator currentVertex;
  vertex_iterator endVertex;

  VPM vpm = CGAL::get(CGAL::vertex_point, P);

  vertex_descriptor vertexHandles[10];
  face_descriptor faceHandles[8];
  Point_3 vertexLocations[10];
  size_t currentVertexIndex = 0;

  for (boost::tie(currentVertex, endVertex) = CGAL::vertices(P); currentVertex != endVertex; ++currentVertex)
  {
    vertexHandles[currentVertexIndex] = *currentVertex;
    vertexLocations[currentVertexIndex] = vpm[*currentVertex];
    ++currentVertexIndex;
  }

  size_t currentFaceIndex = 0;

  for (face_iterator currentFace = startFace; currentFace != endFace; ++currentFace)
  {
    faceHandles[currentFaceIndex] = *currentFace;
    ++currentFaceIndex;
  }

  Barycentric_coordinate startLocation = construct_barycentric_coordinate(FT(0.1), FT(0.8), FT(0.1));

  typedef boost::property_map<Polyhedron_3, CGAL::face_external_index_t>::type FaceIndexMap;

  FaceIndexMap faceIndexMap(CGAL::get(CGAL::face_external_index, P));

  Surface_mesh_shortest_path shortestPaths(P, traits);
  //shortestPaths.m_debugOutput = true;
  shortestPaths.add_source_point(*startFace, startLocation);
  shortestPaths.build_sequence_tree();

  Triangle_3 firstTriangle(vertexLocations[1], vertexLocations[0], vertexLocations[2]);

  Point_3 locationInTriangle(construct_barycenter_in_triangle_3(firstTriangle, startLocation));

  FT dist0 = shortestPaths.shortest_distance_to_source_points(vertexHandles[0]).first;
  CHECK_CLOSE(dist0, CGAL::sqrt(compute_squared_distance_3(locationInTriangle, vertexLocations[0])), FT(0.000001));

//.........这里部分代码省略.........