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CGAL 4.10.2 - 3D Triangulations
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RegularTriangulationTraits_3 Concept Reference
Concepts

Definition

The concept RegularTriangulationTraits_3 is the first template parameter of the class CGAL::Regular_triangulation_3. It defines the geometric objects (points, segments...) forming the triangulation together with a few geometric predicates and constructions on these objects.

We use here the same notation as in Section Regular Triangulation. To simplify notation, \( p\) will often denote in the sequel either the point \( p\in\mathbb{R}^3\) or the weighted point \( {p}^{(w)}=(p,w_p)\).

Refines:
TriangulationTraits_3

In addition to the requirements described for the traits class of CGAL::Triangulation_3, the geometric traits class of CGAL::Regular_triangulation_3 must fulfill the following requirements.

Has Models:
All CGAL Kernels

Types

typedef unspecified_type Line_3
 The line type.
 
typedef unspecified_type Object_3
 The object type.
 
typedef unspecified_type Plane_3
 The plane type.
 
typedef unspecified_type Ray_3
 The ray type.
 
typedef unspecified_type Point_3
 The (unweighted) point type. More...
 
typedef unspecified_type Weighted_point_3
 The weighted point type. More...
 
typedef unspecified_type Power_side_of_oriented_power_sphere_3
 A predicate object, model of Kernel::PowerSideOfOrientedPowerSphere_3, that must provide the following function operators: More...
 
typedef unspecified_type Compare_power_distance_3
 A predicate object, model of ComparePowerDistance_3, that must provide the function operator. More...
 
typedef unspecified_type Construct_weighted_circumcenter_3
 A constructor type, model of ConstructWeightedCircumcenter_3. More...
 
typedef unspecified_type Construct_object_3
 A constructor object that must provide the function operators. More...
 
typedef unspecified_type Construct_perpendicular_line_3
 A constructor object that must provide the function operator. More...
 
typedef unspecified_type Construct_plane_3
 A constructor object that must provide the function operator. More...
 
typedef unspecified_type Construct_ray_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 ()
 
Compare_power_distance_3 compare_power_distance_3_object ()
 

The following functions must be provided only if the member functions of CGAL::Regular_triangulation_3 returning elements of the dual diagram are called:

Construct_weighted_circumcenter_3 construct_weighted_circumcenter_3_object ()
 
Construct_object_3 construct_object_3_object ()
 
Construct_perpendicular_line_3 construct_perpendicular_line_object ()
 
Construct_plane_3 construct_plane_3_object ()
 
Construct_ray_3 construct_ray_3_object ()
 

Member Typedef Documentation

typedef unspecified_type RegularTriangulationTraits_3::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),

which compares the power distance between p and q to the power distance between p and r.

Note
This predicate is required if a call to nearest_power_vertex() or nearest_power_vertex_in_cell() is issued.
typedef unspecified_type RegularTriangulationTraits_3::Construct_object_3

A constructor object that must provide the function operators.

Object_3 operator()(Point_3 p),

Object_3 operator()(Segment_3 s) and

Object_3 operator()(Ray_3 r)

that construct an object respectively from a point, a segment and a ray.

Note
Only required when the dual operations are used.
typedef unspecified_type RegularTriangulationTraits_3::Construct_perpendicular_line_3

A constructor object that must provide the function operator.

Line_3 operator()(Plane_3 pl, Point_3 p),

which constructs the line perpendicular to pl passing through p.

Note
Only required when the dual operations are used.
typedef unspecified_type RegularTriangulationTraits_3::Construct_plane_3

A constructor object that must provide the function operator.

Plane_3 operator()(Point_3 p, Point_3 q, Point_3 r),

which constructs the plane passing through p, q and r.

Precondition
p, q and r are non collinear.
Note
Only required when the dual operations are used.
typedef unspecified_type RegularTriangulationTraits_3::Construct_ray_3

A constructor object that must provide the function operator.

Ray_3 operator()(Point_3 p, Line_3 l),

which constructs the ray starting at p with direction given by l.

Note
Only required when the dual operations are used.
typedef unspecified_type RegularTriangulationTraits_3::Construct_weighted_circumcenter_3

A constructor type, model of ConstructWeightedCircumcenter_3.

The operator() constructs the bare point which is the center of the smallest orthogonal sphere to the input weighted points.

Point_3 operator() ( Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 r, Weighted_point_3 s);

Note
Only required when the dual operations are used.
typedef unspecified_type RegularTriangulationTraits_3::Point_3

The (unweighted) point type.

It has to be a model of the concept Kernel::Point_3.

typedef unspecified_type RegularTriangulationTraits_3::Power_side_of_oriented_power_sphere_3

A predicate object, model of Kernel::PowerSideOfOrientedPowerSphere_3, that must provide the following 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),

which performs the following:

Let \( {z(p,q,r,s)}^{(w)}\) be the power sphere of the weighted points \( (p,q,r,s)\). Returns

  • ON_ORIENTED_BOUNDARY if t is orthogonal to \( {z(p,q,r,s)}^{(w)}\),
  • ON_NEGATIVE_SIDE if t lies outside the oriented sphere of center \( z(p,q,r,s)\) and radius \( \sqrt{ w_{z(p,q,r,s)}^2 + w_t^2 }\) (which is equivalent to \( \Pi({t}^{(w)},{z(p,q,r,s)}^{(w)}) >0\)),
  • ON_POSITIVE_SIDE if t lies inside this oriented sphere.
Precondition
p, q, r, s are not coplanar. Note that with this definition, if all the points have a weight equal to 0, then power_side_of_oriented_power_sphere_3(p,q,r,s,t) = side_of_oriented_sphere(p,q,r,s,t).

Oriented_side operator()( Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 r, Weighted_point_3 t),

which has a definition analogous to the previous method, for coplanar points, with the power circle \( {z(p,q,r)}^{(w)}\).

Precondition
p, q, r are not collinear and p, q, r, t are coplanar. If all the points have a weight equal to 0, then power_side_of_oriented_power_sphere_3(p,q,r,t) = side_of_oriented_circle(p,q,r,t).

Oriented_side operator()( Weighted_point_3 p, Weighted_point_3 q, Weighted_point_3 t),

which is the same for collinear points, where \( {z(p,q)}^{(w)}\) is the power segment of p and q.

Precondition
p and q have different bare points, and p, q, t are collinear. If all points have a weight equal to 0, then power_side_of_oriented_power_sphere_3(p,q,t) gives the same answer as the kernel predicate s(p,q).has_on(t) would give, where s(p,q) denotes the segment with endpoints p and q.

Oriented_side operator()( Weighted_point_3 p, Weighted_point_3 q),

which is the same for equal bare points, then it returns the comparison of the weights (ON_POSITIVE_SIDE when q is heavier than p).

Precondition
p and q have equal bare points.
typedef unspecified_type RegularTriangulationTraits_3::Weighted_point_3

The weighted point type.

It has to be a model of the concept Kernel::WeightedPoint_3, and it must be implicitely convertible from and to Point_3.