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 * Point Cloud Library (PCL) - www.pointclouds.org
 * Copyright (c) 2009-2012, Willow Garage, Inc.
 * Copyright (c) 2012-, Open Perception, Inc.
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#ifndef PCL_GEOMETRY_MESH_ELEMENTS_H
#define PCL_GEOMETRY_MESH_ELEMENTS_H

#include <pcl/geometry/mesh_indices.h>

namespace pcl
{
  namespace geometry
  {
    template <class DerivedT, class MeshTraitsT, class MeshTagT>
    class MeshBase;

    template <class MeshT>
    class MeshIO;
  } // End namespace geometry
} // End namespace pcl

////////////////////////////////////////////////////////////////////////////////
// Vertex
////////////////////////////////////////////////////////////////////////////////

namespace pcl
{
  namespace geometry
  {
    /** \brief A vertex is a node in the mesh.
      * \author Martin Saelzle
      * \ingroup geometry
      */
    class Vertex
    {
      private:

        typedef pcl::geometry::HalfEdgeIndex HalfEdgeIndex;

        /** \brief Constructor.
          * \param[in] idx_outgoing_half_edge Index to the outgoing half-edge. Defaults to an invalid index.
          */
        explicit Vertex (const HalfEdgeIndex& idx_outgoing_half_edge = HalfEdgeIndex ())
          : idx_outgoing_half_edge_ (idx_outgoing_half_edge)
        {}

        /** \brief Index to the outgoing half-edge. The vertex is considered to be deleted if it stores an invalid outgoing half-edge index. */
        HalfEdgeIndex idx_outgoing_half_edge_;

        template <class DerivedT, class MeshTraitsT, class MeshTagT>
        friend class pcl::geometry::MeshBase;

        template <class MeshT>
        friend class pcl::geometry::MeshIO;
    };
  } // End namespace geometry
} // End namespace pcl

////////////////////////////////////////////////////////////////////////////////
// HalfEdge
////////////////////////////////////////////////////////////////////////////////

namespace pcl
{
  namespace geometry
  {
    /** \brief An edge is a connection between two vertices. In a half-edge mesh the edge is split into two half-edges with opposite orientation. Each half-edge stores the index to the terminating vertex, the next half-edge, the previous half-edge and the face it belongs to. The opposite half-edge is accessed implicitly.
      * \author Martin Saelzle
      * \ingroup geometry
      */
    class HalfEdge
    {
      private:

        typedef pcl::geometry::VertexIndex   VertexIndex;
        typedef pcl::geometry::HalfEdgeIndex HalfEdgeIndex;
        typedef pcl::geometry::FaceIndex     FaceIndex;

        /** \brief Constructor.
          * \param[in] idx_terminating_vertex Index to the terminating vertex. Defaults to an invalid index.
          * \param[in] idx_next_half_edge     Index to the next half-edge. Defaults to an invalid index.
          * \param[in] idx_prev_half_edge     Index to the previous half-edge. Defaults to an invalid index.
          * \param[in] idx_face               Index to the face. Defaults to an invalid index.
          */
        explicit HalfEdge (const VertexIndex&   idx_terminating_vertex = VertexIndex   (),
                           const HalfEdgeIndex& idx_next_half_edge     = HalfEdgeIndex (),
                           const HalfEdgeIndex& idx_prev_half_edge     = HalfEdgeIndex (),
                           const FaceIndex&     idx_face               = FaceIndex     ())
          : idx_terminating_vertex_ (idx_terminating_vertex),
            idx_next_half_edge_     (idx_next_half_edge),
            idx_prev_half_edge_     (idx_prev_half_edge),
            idx_face_               (idx_face)
        {
        }

        /** \brief Index to the terminating vertex. The half-edge is considered to be deleted if it stores an invalid terminating vertex index. */
        VertexIndex idx_terminating_vertex_;

        /** \brief Index to the next half-edge. */
        HalfEdgeIndex idx_next_half_edge_;

        /** \brief Index to the previous half-edge. */
        HalfEdgeIndex idx_prev_half_edge_;

        /** \brief Index to the face. The half-edge is considered to be on the boundary if it stores an invalid face index. */
        FaceIndex idx_face_;

        template <class DerivedT, class MeshTraitsT, class MeshTagT>
        friend class pcl::geometry::MeshBase;

        template <class MeshT>
        friend class pcl::geometry::MeshIO;
    };
  } // End namespace geometry
} // End namespace pcl

////////////////////////////////////////////////////////////////////////////////
// Face
////////////////////////////////////////////////////////////////////////////////

namespace pcl
{
  namespace geometry
  {
    /** \brief A face is a closed loop of edges.
      * \author Martin Saelzle
      * \ingroup geometry
      */
    class Face
    {
      private:

        typedef pcl::geometry::HalfEdgeIndex HalfEdgeIndex;

        /** \brief Constructor.
          * \param[in] inner_half_edge_idx Index to the outgoing half-edge. Defaults to an invalid index
          */
        explicit Face (const HalfEdgeIndex& idx_inner_half_edge = HalfEdgeIndex ())
          : idx_inner_half_edge_ (idx_inner_half_edge)
        {}

        /** \brief Index to the inner half-edge. The face is considered to be deleted if it stores an invalid inner half-edge index. */
        HalfEdgeIndex idx_inner_half_edge_;

        template <class DerivedT, class MeshTraitsT, class MeshTagT>
        friend class pcl::geometry::MeshBase;

        template <class MeshT>
        friend class pcl::geometry::MeshIO;
    };
  } // End namespace geometry
} // End namespace pcl

#endif // PCL_GEOMETRY_MESH_ELEMENTS_H
