CGAL 5.0 - 3D Periodic Triangulations
Periodic_3DelaunayTriangulationTraits_3 Concept Reference

## Definition

The concept Periodic_3DelaunayTriangulationTraits_3 is the first template parameter of the class CGAL::Periodic_3_Delaunay_triangulation_3. It refines the concepts Periodic_3TriangulationTraits_3 and DelaunayTriangulationTraits_3. It redefines the geometric objects, predicates and constructions to work with point-offset pairs. In most cases the offsets will be (0,0,0) and the predicates from DelaunayTriangulationTraits_3 can be used directly. For efficiency reasons we maintain for each functor the version without offsets.

Refines:

Periodic_3TriangulationTraits_3

DelaunayTriangulationTraits_3

Has Models:
CGAL::Periodic_3_Delaunay_triangulation_traits_3

In addition to the requirements described by the concepts Periodic_3TriangulationTraits_3 and DelaunayTriangulationTraits_3, the geometric traits class of a Periodic Delaunay triangulation must fulfill the following requirements.

Note
The optional types must be provided in any case, however they can be replaced by dummy types if the respective functions are not used.
 typedef unspecified_type Side_of_oriented_sphere_3 A predicate object that must provide the function operator. More... typedef unspecified_type Compare_distance_3 A predicate object that must provide the function operator. More... When vertex removal is used, the traits class must in addition provide the following predicate objects typedef unspecified_type Coplanar_orientation_3 A predicate object that must provide the function operator. More... typedef unspecified_type Coplanar_side_of_bounded_circle_3 A predicate object that must provide the function operator. More... When is_Gabriel is used, the traits class must in addition provide the following predicate object: typedef unspecified_type Side_of_bounded_sphere_3 A predicate object that must provide the function operator. More... When the dual operations are used, the traits class must in addition provide the following constructor object: typedef unspecified_type Construct_circumcenter_3 A constructor object that must provide the function operator. More...

## Operations

Side_of_oriented_sphere_3 side_of_oriented_sphere_3_object ()

Compare_distance_3 compare_distance_3_object ()

The following functions must be provided if vertex removal is used; otherwise dummy functions can be provided.

Coplanar_orientation_3 coplanar_3_orientation_3_object ()

Coplanar_side_of_bounded_circle_3 coplanar_side_of_bounded_circle_3_object ()

The following function must be provided if the is_Gabriel methods of Periodic_3_Delaunay_triangulation_3 are used; otherwise a dummy function can be provided.

Side_of_bounded_sphere_3 side_of_bounded_sphere_3_object ()

The following function must be provided if the methods of Periodic_3_Delaunay_triangulation_3 returning elements of the Voronoi diagram are used; otherwise a dummy function can be provided:

Construct_circumcenter_3 construct_circumcenter_3_object ()

## ◆ Compare_distance_3

A predicate object that must provide the function operator.

Comparison_result operator()(Point_3 p, Point_3 q, Point_3 r, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_r),

which compares the distance between (p,o_p) and (q,o_q) to the distance between (p,o_p) and (r,o_r).

Precondition
p, q, r lie inside the domain.

## ◆ Construct_circumcenter_3

A constructor object that must provide the function operator.

Point_3 operator()(Point_3 p, Point_3 q, Point_3 r, Point_3 s, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_r, Periodic_3_offset_3 o_s),

which constructs the circumcenter of four point-offset pairs.

Precondition
p, q, r and s as well as (p,o_p), (q,o_q), (r,o_r) and (s,o_s) must be non coplanar. p, q, r, s lie inside the domain.

## ◆ Coplanar_orientation_3

A predicate object that must provide the function operator.

Orientation operator()(Point_3 p, Point_3 q, Point_3 r Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_r),

which returns COLLINEAR, if the point-offset pairs are collinear; otherwise it must return a consistent orientation for any three point-offset pairs chosen in a same plane.

Precondition
p, q, r lie inside the domain.

## ◆ Coplanar_side_of_bounded_circle_3

A predicate object that must provide the function operator.

Bounded_side operator()(Point_3 p, Point_3 q, Point_3 r, Point_3 s, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_r, Periodic_3_offset_3 o_s),

which determines the bounded side of the circle defined by (p,o_p), (q,o_q), and (r,o_r) on which the point-offset pair (s,o_s) lies.

Precondition
p,q,r, and s are coplanar and p,q, and r are not collinear, (p,o_p),(q,o_q),(r,o_r), and (s,o_s) are coplanar and (p,o_p),(q,o_q), and (r,o_r) are not collinear, respectively, and p, q, r, s, t lie inside the domain.

## ◆ Side_of_bounded_sphere_3

A predicate object that must provide the function operator.

Bounded_side operator()(Point_3 p, Point_3 q, Point_3 t, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_t),

which returns the position of the point-offset pair (t,o_t) relative to the sphere that has (p,o_p)(q,o_q) as its diameter,

Bounded_side operator()(Point_3 p, Point_3 q, Point_3 r, Point_3 t, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_r, Periodic_3_offset_3 o_q),

which returns the position of the point-offset pair (t,o_t) relative to the sphere passing through (p,o_p), (q,o_q), and (r,o_r) and whose center is in the plane defined by these three point-offset pairs.

## ◆ Side_of_oriented_sphere_3

A predicate object that must provide the function operator.

Oriented_side operator()(Point_3 p, Point_3 q, Point_3 r, Point_3 s, Point_3 t, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_r, Periodic_3_offset_3 o_s, Periodic_3_offset_3 o_t),

which determines on which side of the oriented sphere circumscribing (p,o_p), (q,o_q), (r,o_r), (s,o_s) the point-offset pair (t,o_t) lies.

Precondition
p, q, r, s, t lie inside the domain.