CGAL::Alpha_status< NT > Class Template Reference

#include <CGAL/Alpha_shape_cell_base_3.h>

Definition

template<typename NT>
class CGAL::Alpha_status< NT >

The class Alpha_status is a small data structure to store the critical alpha values of faces of an alpha shape.

Each face has three critical alpha values, called alpha_min, alpha_mid and alpha_max in increasing order. The face will be exterior for any \( \alpha < \) alpha_min, singular for alpha_min \( \leq \alpha < \) alpha_mid, regular for alpha_mid \( \leq \alpha < \) alpha_max and interior for alpha_max \( \leq \alpha\). The value alpha_min is undefined for faces which are not Gabriel faces and therefore do not appear in the alpha complex without any of their including face. The value alpha_max is undefined for convex hull faces which can never be interior. The data structure also includes two Boolean to mark if the face is a Gabriel face or a convex hull face.

The class Alpha_status is parameterized by a number type NT.

See also

AlphaShapeCell_3

AlphaShapeVertex_3

Creation
	Alpha_status ()
	default constructor.

Modifiers
void	set_is_Gabriel (bool yesorno)
	sets Gabriel marker.
void	set_is_on_chull (bool yesorno)
	sets convex hull marker.
void	set_alpha_min (NT alpha)
	sets alpha_min.
void	set_alpha_mid (NT alpha)
	sets alpha_mid.
void	set_alpha_max (NT alpha)
	sets alpha_max.

Access Functions
bool	is_Gabriel () const
	returns true for Gabriel faces.
bool	is_on_chull () const
	returns true for convex hull faces.
NT	alpha_min () const
	returns the alpha_min.
NT	alpha_mid () const
	returns alpha_mid.
NT	alpha_max () const
	returns alpha_max.

Member Function Documentation

alpha_max()

template<typename NT >

NT CGAL::Alpha_status< NT >::alpha_max

(

)

const

returns alpha_max.

Precondition

is_on_chull() returns false.

alpha_min()

template<typename NT >

NT CGAL::Alpha_status< NT >::alpha_min

(

)

const

returns the alpha_min.

Precondition

is_Gabriel() returns false.