Requirements for Vertex_base

Definition

A vertex optionally stores a point and a reference to an incident halfedge that points to the vertex. Type tags indicate whether these member functions are supported. Figure  depicts the relationship between a halfedge and its incident halfedges, vertices, and facets.

Types

Type for (optional) associated geometry. If a point is not supported the type is void*.

Vertex_base::Point
	point type stored in vertices.

Creation

Vertex_base v;
	default constructor.
Vertex_base v ( const Vertex&);
	copy constructor.
Vertex_base v ( const Point& p);
	must exist if points are supported.

Operations

void*	v.halfedge ()	an incident halfedge pointing towards v.
const void*	v.halfedge () const
Point&	v.point ()	the point.
const Point&	v.point () const
void	v.set_halfedge ( void* h)
		set incident halfedge.

Types for Tagging Optional Features

The following types are equal to either Tag_true or Tag_false, depending on whether the named member function is supported or not.

Vertex_base::Supports_vertex_point
	point().
Vertex_base::Supports_vertex_halfedge
	halfedge().