|
The concept AABBPrimitive 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 AABBPrimitive also refines the concepts DefaultConstructible and Assignable.
| Datum | primitive.datum () | Returns the datum (geometric object) represented by the primitive. |
| Id | primitive.id () | Returns the corresponding identifier. This identifier is only used as a reference for the objects in the output of the AABB_tree methods. |
| Point | primitive.reference_point () | Returns a 3D 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. |
The Primitive type can be, e.g., a wrapper around a Handle. Assume for instance that the input objects are the triangle faces of a mesh stored as a CGAL::Polyhedron. The Datum would be a Triangle_3 and the Id would be a polyhedron Face_handle. Method datum() can return either a Triangle_3 constructed on the fly from the face handle or a Triangle_3 stored internally. This provides a way for the user to trade memory for efficiency.