CGAL::Nef_polyhedron_S2< Traits >::SHalfedge Class Reference

#include <CGAL/Nef_polyhedron_S2.h>

Definition

A shalfedge is a great arc on a sphere map.

The figure below depicts the relationship between a shalfedge and its incident shalfedges, svertices, and sfaces on a sphere map. A shalfedge is an oriented sedge between two svertices. It is always paired with a shalfedge pointing in the opposite direction. The twin() member function returns this shalfedge of opposite orientation.

Incidences of an SHalfedge

The snext() member function points to the successor shalfedge around this sface while the sprev() member function points to the preceding shalfedge. An successive assignments of the form se = se->snext() cycles counterclockwise around the sface (or hole).

Similarly, the successive assignments of the form se = se->snext()->twin() cycle clockwise around the svertex and traverse all halfedges incident to this svertex. The assignment se = se->cyclic_adj_succ() can be used as a shortcut.

A const circulator is provided for each of the two circular orders. The circulators are bidirectional and assignable to SHalfedge_const_handle.

Creation

There is no need for a user to create a SHalfedge explicitly. The class Nef_polyhedron_S2<Traits> manages the needed shalfedges internally.

See also

CGAL::Nef_polyhedron_S2::SVertex

CGAL::Nef_polyhedron_S2::SFace

CGAL::Nef_polyhedron_S2::Sphere_circle

Types
The following types are the same as in Nef_polyhedron_S2<Traits>.
typedef unspecified_type	Mark
	type of mark.
typedef unspecified_type	Sphere_circle
	sphere circle type stored in SHalfedge.
typedef unspecified_type	SVertex_const_handle
	const handle to SVertex.
typedef unspecified_type	SHalfedge_const_handle
	const handle to SHalfedge.
typedef unspecified_type	SFace_const_handle
	const handle to SFace.

Operations
const Mark &	mark () const
	the mark of the sedge.
const Sphere_circle &	circle () const
	the sphere circle of the sedge.
SHalfedge_const_handle	twin () const
	the twin of the sedge.
SVertex_const_handle	source () const
	the source svertex of the sedge.
SVertex_const_handle	target () const
	equals twin()->source().
SHalfedge_const_handle	sprev () const
	the SHalfedge previous to the sedge in a sface cycle.
SHalfedge_const_handle	snext () const
	the next SHalfedge of the sedge in a sface cycle.
SHalfedge_const_handle	cyclic_adj_pred () const
	the edge before the sedge in the cyclic ordered adjacency list of source().
SHalfedge_const_handle	cyclic_adj_succ () const
	the edge after the sedge in the cyclic ordered adjacency list of source().
SFace_const_handle	incident_sface () const
	the incident sface of the sedge.
bool	in_outer_sface_cycle () const
	determines whether the sedge is in an outer sface cycle.
bool	in_inner_sface_cycle () const
	determines whether the sedge is in an inner sface cycle.