TriangulationDSFaceBase_2

Definition

Note that if the Triangulation_data_structure_2 is plugged into a triangulation class, the face base class may have additional geometric requirements depending on the triangulation class.

At the base level, (see Sections 20.3 and 21.3), a face stores handles on its three vertices and on the three neighboring faces. The vertices and neighbors are indexed 0,1 and 2. Neighbor $$i lies opposite to vertex $$i.

Since the Triangulation_data_structure_2 is the class which defines the handle types, the face base class has to be somehow parameterized by the triangulation data structure. But since the Triangulation_data_structure_2 itself is parameterized by the face and vertex base classes, there is a cycle in the definition of these classes. In order to break the cycle, the base classes for faces and vertices which are plugged in to instantiate a Triangulation_data_structure_2 use a void as triangulation data structure parameter. Then, the Triangulation_data_structure_2 uses a rebind mechanism (similar to the one specified in std::allocator) in order to plug itself as parameter in the face and vertex base classes. This mechanism requires that the base class provides a templated nested class Rebind_TDS that itself provides the subtype Rebind_TDS<TDS2>::Other which is the rebound version of the base class. This rebound base class is the class that the Triangulation_data_structure_2 actually uses as a base class for the class Triangulation_data_structure_2::Face.

Types

template <typename TDS2>
TriangulationDSFaceBase_2:: struct Rebind_TDS;
	This nested template class has to define a type Other which is the rebound face base, where the Triangulation_data_structure_2 is actually plugged in. This type Other will be the actual base of the class Triangulation_data_structure_2::Face.

typedef TriangulationDataStructure_2
	Triangulation_data_structure;
typedef TriangulationDataStructure_2::Vertex_handle
	Vertex_handle;
typedef TriangulationDataStructure_2::Face_handle
	Face_handle;

Creation

Access Functions

int	f.dimension ()	returns the dimension.
Vertex_handle	f.vertex ( int i)	returns the vertex i of f . Precondition: $$0 i 2.
bool	f.has_vertex ( Vertex_handle v)
		returns true if v is a vertex of f .
bool	f.has_vertex ( Vertex_handle v, int& i)
		as above, and sets i to the index of v in f .
int	f.index ( Vertex_handle v)
		returns the index of v in f .
Face_handle	f.neighbor ( int i)
		returns the neighbor i of f . Precondition: $$0 i 2.
bool	f.has_neighbor ( Face_handle n)
		returns true if n is a neighbor of f .
bool	f.has_neigbor ( Face_handle n, int& i)
		as above, and sets i to the index of n in f .
int	f.index ( const Face_handle n)
		returns the index of neighbor n in f .

Setting

void	f.set_vertex ( int i, Vertex_handle v)
		sets vertex i to v. Precondition: $$0 i 2.
void	f.set_vertices ()	sets the vertices to Vertex_handle().
void	f.set_vertices ( Vertex_handle v0, Vertex_handle v1, Vertex_handle v2)
		sets the vertices.
void	f.set_neighbor ( int i, Face_handle n)
		sets neighbors i to n. Precondition: $$0 i 2.
void	f.set_neighbors ()	sets the neighbors to Face_handle().
void	f.set_neighbors ( Face_handle n0, Face_handle n1, Face_handle n2)
		sets the neighbors.

Orientation

Checking

Various

void *	f.for_compact_container ()
void * &	f.for_compact_container ()

These member functions are required by Triangulation_data_structure_2 because it uses Compact_container to store its faces. See the documentation of Compact_container for the exact requirements.

Has Models

See Also