text: // Copyright (c) 2018 GeometryFactory Sarl (France).
  // All rights reserved.
  //
  // This file is part of CGAL (www.cgal.org).
  //
  // $URL$
  // $Id$
  // SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
  //
  // Author(s)     : Simon Giraudot
  
  #ifndef CGAL_CLASSIFICATION_PROPERTY_MAPS_H
  #define CGAL_CLASSIFICATION_PROPERTY_MAPS_H
  
  #include <CGAL/license/Classification.h>
  
  #include <CGAL/centroid.h>
  #include <CGAL/Bbox_3.h>
  #include <CGAL/property_map.h>
  
  #include <CGAL/boost/graph/properties.h>
  
  namespace CGAL
  {
  
  namespace Classification
  {
  
  /*!
    \ingroup PkgClassificationMesh
  
    \brief Property map that constructs the center of mass of the face
    of a mesh on-the-fly.
  
    \cgalModels `ReadablePropertyMap`
  
    \tparam FaceGraph model of `FaceGraph`.
  
    \tparam VertexPointMap model of `ReadablePropertyMap` with with
    `boost::graph_traits<FaceGraph>::%vertex_descriptor` as key type
    and `CGAL::Point_3` as value type.
  */
  template <typename FaceGraph,
            typename VertexPointMap = typename boost::property_map<FaceGraph,vertex_point_t>::type >
  class Face_descriptor_to_center_of_mass_map
  {
  public:
    typedef typename boost::property_traits<VertexPointMap>::value_type Point_3;
    typedef typename boost::graph_traits<FaceGraph>::face_descriptor key_type;
    typedef Point_3 value_type;
    typedef Point_3 reference;
    typedef boost::readable_property_map_tag category;
  
  private:
    typedef typename boost::graph_traits<FaceGraph>::vertex_descriptor vertex_descriptor;
  
    const FaceGraph* m_mesh;
    VertexPointMap m_vpm;
  
  public:
  
    Face_descriptor_to_center_of_mass_map ()
      : m_mesh (nullptr) { }
    Face_descriptor_to_center_of_mass_map (const FaceGraph* mesh)
      : m_mesh (mesh), m_vpm (get (vertex_point, *m_mesh)) { }
    Face_descriptor_to_center_of_mass_map (const FaceGraph* mesh, VertexPointMap vpm)
      : m_mesh (mesh), m_vpm (vpm) { }
  
    /// \cond SKIP_IN_MANUAL
    inline friend value_type get (const Face_descriptor_to_center_of_mass_map& map, key_type f)
    {
      std::vector<Point_3> points;
  
      for(vertex_descriptor v : vertices_around_face(halfedge(f, *(map.m_mesh)), *(map.m_mesh)))
        points.push_back (get (map.m_vpm, v));
  
      return CGAL::centroid (points.begin(), points.end());
    }
    /// \endcond
  };
  
  /*!
    \ingroup PkgClassificationMesh
  
    \brief Property map that constructs a face descriptor with a
    `bbox()` method from a face descriptor.
  
    \cgalModels `ReadablePropertyMap`
  
    \tparam FaceGraph model of `FaceGraph`.
  
    \tparam VertexPointMap model of `ReadablePropertyMap` with with
    `boost::graph_traits<FaceGraph>::%vertex_descriptor` as key type
    and `CGAL::Point_3` as value type.
  */
  template <typename FaceGraph,
            typename VertexPointMap = typename boost::property_map<FaceGraph,vertex_point_t>::type >
  class Face_descriptor_to_face_descriptor_with_bbox_map
  {
  public:
    typedef typename boost::graph_traits<FaceGraph>::face_descriptor face_descriptor;
  
    /*!
      \brief Face descriptor with a precomputed bounding box.
    */
    class face_descriptor_with_bbox
    {
      face_descriptor m_descriptor;
      CGAL::Bbox_3 m_bbox;
  
    public:
      face_descriptor_with_bbox (const face_descriptor& descriptor,
                                 const CGAL::Bbox_3& bbox)
        : m_descriptor (descriptor), m_bbox (bbox)
      { }
  
      const CGAL::Bbox_3 bbox() const { return m_bbox; }
      operator face_descriptor() const { return m_descriptor; }
    };
  
    typedef face_descriptor key_type;
    typedef face_descriptor_with_bbox value_type;
    typedef face_descriptor_with_bbox reference;
    typedef boost::readable_property_map_tag category;
  
  private:
    typedef typename boost::graph_traits<FaceGraph>::vertex_descriptor vertex_descriptor;
  
    const FaceGraph* m_mesh;
    VertexPointMap m_vpm;
  
  public:
  
    Face_descriptor_to_face_descriptor_with_bbox_map ()
      : m_mesh (nullptr) { }
    Face_descriptor_to_face_descriptor_with_bbox_map (const FaceGraph* mesh)
      : m_mesh (mesh), m_vpm (get (vertex_point, *m_mesh)) { }
    Face_descriptor_to_face_descriptor_with_bbox_map (const FaceGraph* mesh, VertexPointMap vpm)
      : m_mesh (mesh), m_vpm (vpm) { }
  
    /// \cond SKIP_IN_MANUAL
    inline friend value_type get (const Face_descriptor_to_face_descriptor_with_bbox_map& map, key_type f)
    {
      CGAL::Bbox_3 bbox;
  
      for(vertex_descriptor v : vertices_around_face(halfedge(f, *(map.m_mesh)), *(map.m_mesh)))
        bbox = bbox + get(map.m_vpm, v).bbox();
  
      return value_type (f, bbox);
    }
    /// \endcond
  };
  
  
  } // namespace Classification
  
  } // namespace CGAL
  
  #endif // CGAL_CLASSIFICATION_PROPERTY_MAPS_H
  