CGAL 6.0.1 - Quadtrees, Octrees, and Orthtrees
Loading...
Searching...
No Matches
CGAL::Orthtree_traits_base< GeomTraits, dim > Struct Template Reference

#include <CGAL/Orthtree_traits_base.h>

Inherited by CGAL::Orthtree_traits_point< GeomTraits, PointRange, PointMap, hypercubic_nodes, dimension >, and CGAL::Orthtree_traits_polygons< GeomTraits >.

Definition

template<typename GeomTraits, int dim>
struct CGAL::Orthtree_traits_base< GeomTraits, dim >

The class Orthtree_traits_base is a base class providing common choices for types and functors.

The base class is extended by CGAL::Orthtree_traits_point<GeomTraits, PointRange, PointMap, dimension> and by CGAL::Orthtree_traits_face_graph<PolygonMesh, VertexPointMap>.

Template Parameters
GeomTraitsa model of Kernel.
dimdimension of the ambient Euclidean space.
See also
CGAL::Orthtree_traits_point<GeomTraits, PointRange, PointMap, dim>
CGAL::Orthtree_traits_face_graph<PolygonMesh, VertexPointMap>

Types

using Node_index = std::size_t
 
using Kernel = GeomTraits
 
using FT = typename GeomTraits::FT
 
using Point_d = typename GeomTraits::Point_d
 
using Bbox_d = typename GeomTraits::Iso_box_d
 
using Sphere_d = typename GeomTraits::Sphere_d
 
using Cartesian_const_iterator_d = typename GeomTraits::Cartesian_const_iterator_d
 
using Adjacency = int
 Adjacency type.
 
static constexpr int dimension = dim
 

Member Typedef Documentation

◆ Adjacency

template<typename GeomTraits , int dim>
using CGAL::Orthtree_traits_base< GeomTraits, dim >::Adjacency = int

Adjacency type.

Note
This type is used to identify adjacency directions with easily understandable keywords (left, right, up, down, ...) and is thus mainly useful in 2D and 3D. In higher dimensions, such keywords do not exist and this type is simply an integer. Conversions from this integer to bitsets still work but do not provide any user-friendly API for adjacency selection.

Two directions along each axis in Cartesian space, relative to a node.

Directions are mapped to numbers as 3-bit integers in the 3D case or as 2-bit integers in the 2D case. In the 3d case the numbers 6 and 7 are not used because there are only 6 different directions.

The first two bits indicate the axis (00 = x, 01 = y, 10 = z), the third bit indicates the direction along that axis (0 = -, 1 = +).

The following diagram and table showing the 3D case may be a useful reference (2D case is identical with one dimension less):

       3 *
         |  * 4
         | /                  y+
         |/                   *
0 *------+------* 1           |
        /|                    |
       / |                    +-----* x+
    5 *  |                   /
         * 2                /
                           * z+

This lookup table may also be helpful:

Direction bitset number Enum
-x 000 0 LEFT
+x 001 1 RIGHT
-y 010 2 DOWN
+y 011 3 UP
-z 100 4 BACK
+z 101 5 FRONT