CGAL 6.1.2 - Fast Intersection and Distance Computation (AABB Tree): AABBPrimitiveWithSharedData Concept Reference

CGAL 6.1.2 - Fast Intersection and Distance Computation (AABB Tree)

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AABBPrimitiveWithSharedData Concept Reference
Reference Manual » Concepts

## Definition

The concept `AABBPrimitiveWithSharedData` describes the requirements for the primitives stored in the AABB tree data structure. The concept encapsulates a type for the input datum (a geometric object) and an identifier (id) type through which those primitives are referred to. The concept `AABBPrimitiveWithSharedData` also refines the concepts `DefaultConstructible` and `Assignable`. The concept is similar to `AABBPrimitive` except that some data stored outside of the primitives are required to access the datum and the reference point.

See also
  `CGAL::AABB_tree<AABBTraits>`
  `AABBPrimitive`

Example

The `Primitive` type can be a wrapper around an integer that refers to the position of an object in a vector. Assume for instance that the input objects are some triangles. The `Datum` would be a `Triangle_3` and the `Id` a `std::size_t`. The shared data here is a `std::vector<Triangle_3>`. The method `datum(const Shared_data&)` then returns a triangle from the vector.

Has models
  `CGAL::AABB_primitive<Id,ObjectPropertyMap,PointPropertyMap,Tag_true,CacheDatum>`
  `CGAL::AABB_halfedge_graph_segment_primitive<HalfedgeGraph,VertexPointPMap,Tag_true,CacheDatum>`
  `CGAL::AABB_face_graph_triangle_primitive<FaceGraph,VertexPointPMap,Tag_true,CacheDatum>`

## Types
typedef unspecified_type | Point
| Point type.
typedef unspecified_type | Datum
| Type of input datum.
typedef unspecified_type | Point_reference
| Point reference type returned by the function `point(const Shared_data&)`.
typedef unspecified_type | Datum_reference
| Datum reference type returned by the function `datum(const Shared_data&)`.
typedef unspecified_type | Id
| Type of identifiers through which the input objects are referred to.
typedef unspecified_type | Shared_data
| Type of the data shared amongst primitives.

## Operations
Datum_reference | datum (const Shared_data &data)
| returns the datum (geometric object) represented by the primitive.
Id | id ()
| returns the corresponding identifier.
Point_reference | reference_point (const Shared_data &data)
| returns a point located on the geometric object represented by the primitive.
template<class ... T>
static Shared_data | construct_shared_data (T ... t)
| constructs the shared data of a primitive.

## Member Typedef Documentation

## ◆ Datum_reference

typedef unspecified_type AABBPrimitiveWithSharedData::Datum_reference

Datum reference type returned by the function `datum(const Shared_data&)`.

It is convertible to the type `Datum`.

## ◆ Id

typedef unspecified_type AABBPrimitiveWithSharedData::Id

Type of identifiers through which the input objects are referred to.

It must be a model of the concepts DefaultConstructible and Assignable.

## ◆ Point_reference

typedef unspecified_type AABBPrimitiveWithSharedData::Point_reference

Point reference type returned by the function `point(const Shared_data&)`.

It is convertible to the type `Point`.

## Member Function Documentation

## ◆ construct_shared_data()

template<class ... T>

static Shared_data AABBPrimitiveWithSharedData::construct_shared_data | ( | T ... | t | ) |
| static

constructs the shared data of a primitive.

The parameter pack is such that there exists a constructor `template <class T1, class ... T> AABBPrimitiveWithSharedData (T1,T...)`.

## ◆ id()

Id AABBPrimitiveWithSharedData::id | ( |  | ) |

returns the corresponding identifier.

This identifier is only used as a reference for the objects in the output of the `AABB_tree` methods.

## ◆ reference_point()

Point_reference AABBPrimitiveWithSharedData::reference_point | ( | const Shared_data & | data | ) |

returns a point located on the geometric object represented by the primitive.

This function is used to sort the primitives during the AABB tree construction as well as to construct the search KD-tree internal to the AABB tree used to accelerate distance queries.