CGAL 4.12.1 - 3D Periodic Triangulations
Periodic_3RegularTriangulationTraits_3 Concept Reference

Definition

The concept Periodic_3RegularTriangulationTraits_3 is the first template parameter of the class CGAL::Periodic_3_regular_triangulation_3. It refines the concept RegularTriangulationTraits_3 from the CGAL 3D Triangulations. 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 RegularTriangulationTraits_3 can be used directly. For efficiency reasons we maintain for each functor the version without offsets.

Refines:

RegularTriangulationTraits_3

Has Models:
CGAL::Periodic_3_regular_triangulation_traits_3

In addition to the requirements described for the traits class RegularTriangulationTraits_3, the geometric traits class of a periodic regular 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 Power_side_of_oriented_power_sphere_3 A predicate object that must provide the function operators. More... typedef unspecified_type Compare_weighted_squared_radius_3 A predicate object that must provide the function operators: More... typedef unspecified_type Compare_power_distance_3 A predicate object, model of ComparePowerDistance_3, that must provide the function operator. More... When vertex removal is used, the traits class must in addition provide the following predicate object typedef unspecified_type Coplanar_orientation_3 A predicate object that must provide the function operators: More... When is_Gabriel functions are used, the traits class must in addition provide the following predicate object: typedef unspecified_type Power_side_of_bounded_power_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_weighted_circumcenter_3 A constructor object that must provide the function operator. More...

Operations

Power_side_of_oriented_power_sphere_3 power_side_of_oriented_power_sphere_3_object ()

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

Coplanar_orientation_3 coplanar_3_orientation_3_object ()

The following function must be provided only if the methods of Periodic_3_regular_triangulation_3 returning elements of the Voronoi diagram are used; otherwise a dummy function can be provided.

Construct_weighted_circumcenter_3 construct_weighted_circumcenter_3_object ()

◆ Compare_power_distance_3

A predicate object, model of ComparePowerDistance_3, that must provide the function operator.

Comparison_result operator()(Point_3 p, Weighted_point_3 q, Weighted_point_3 r, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_r),

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

Note
This predicate is required if a call to nearest_power_vertex() or nearest_power_vertex_in_cell() is issued.

A predicate object that must provide the function operators:

Orientation operator()(Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 r, Weighted_point_3 s, FT w),

which compares the weight of the smallest sphere orthogonal to the input weighted points with the input weight w and returns a SMALLER, EQUAL, or LARGER.

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

◆ Construct_weighted_circumcenter_3

A constructor object that must provide the function operator.

Weighted_point_3 operator()(Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 r, Weighted_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 weighted circumcenter of four point-offset pairs.

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

◆ Coplanar_orientation_3

A predicate object that must provide the function operators:

Orientation operator()(Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 r),

which returns COLLINEAR, if the points are collinear; otherwise it must return a consistent orientation for any three points chosen in a same plane and

Orientation operator()(Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 r, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_r),

which is the same for point-offset pairs.

Precondition
p, q, r lie inside the domain.

◆ Power_side_of_bounded_power_sphere_3

A predicate object that must provide the function operator.

Bounded_side operator()(Weighted_point_3 p, Weighted_point_3 t, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_t),

which returns the sign of the power test of (t,o_t) with respect to the smallest sphere orthogonal to (p,o_p) (which is the sphere with center (p,o_p) and squared radius -w_p with w_p the weight of p),

Bounded_side operator()(Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 t, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_t),

which returns the sign of the power test of (t,o_t) with respect to the smallest sphere orthogonal to (p,o_p) and (q,o_q),

Bounded_side operator()(Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 r, Weighted_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 sign of the power test of (t,o_t) with respect to the smallest sphere orthogonal to (p,o_p), (q,o_q), and (r,o_r).

◆ Power_side_of_oriented_power_sphere_3

A predicate object that must provide the function operators.

Oriented_side operator()(Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 r, Weighted_point_3 s, Weighted_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 the position of the point-offset pair (t,o_t) with respect to the power sphere of the point-offset pairs (p,o_p), (q,o_q), (r,o_r), (s,o_s).

Precondition
p, q, r, s, t lie inside the domain and p, q, r, s are not coplanar.

When vertex removal is used, the predicate must in addition provide the function operators

Oriented_side operator()(Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 r, Weighted_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_t),

which has a definition similar to the previous method, for coplanar points, with the power circle of p,q,r.

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

Oriented_side operator()(Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 t, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q, Periodic_3_offset_3 o_t),

which is the same for collinear points, and the power segment of (p,o_p) and (q,o_q),

Precondition
p, q, t lie inside the domain, p and q have different Bare_points, and (p,o_p), (q,o_q), (t,o_t) are collinear.

Oriented_side operator()(Weighted_point_3 p, Weighted_point_3 q, Periodic_3_offset_3 o_p, Periodic_3_offset_3 o_q),

which is the same for equal points, that is when (p,o_p) and (q,o_q) have equal coordinates, then it returns the comparison of the weights.

Precondition
p and q lie inside the domain and have equal Bare_points.