CGAL::Direction_3< Kernel > Class Template Reference

#include <CGAL/Direction_3.h>

Definition

An object of the class Direction_3 is a vector in the three-dimensional vector space \( \mathbb{R}^3\) where we forget about their length.

They can be viewed as unit vectors, although there is no normalization internally, since this is error prone. Directions are used whenever the length of a vector does not matter. They also characterize a set of parallel lines that have the same orientation or the direction normal to parallel planes that have the same orientation. For example, you can ask for the direction orthogonal to an oriented plane, or the direction of an oriented line.

Is Model Of:

Kernel::Direction_3

Creation
	Direction_3 (const Vector_3< Kernel > &v)
	introduces a direction d initialized with the direction of vector v.
	Direction_3 (const Line_3< Kernel > &l)
	introduces the direction d of line l.
	Direction_3 (const Ray_3< Kernel > &r)
	introduces the direction d of ray r.
	Direction_3 (const Segment_3< Kernel > &s)
	introduces the direction d of segment s.
	Direction_3 (const Kernel::RT &x, const Kernel::RT &y, const Kernel::RT &z)
	introduces a direction d initialized with the direction from the origin to the point with Cartesian coordinates \( (x, y, z)\).

Operations
Kernel::RT	delta (int i) const
	returns values, such that d== Direction_3<Kernel>(delta(0),delta(1),delta(2)). More...
Kernel::RT	dx () const
	returns delta(0).
Kernel::RT	dy () const
	returns delta(1).
Kernel::RT	dz () const
	returns delta(2).
bool	operator== (const Direction_3< Kernel > &e) const
	Test for equality.
bool	operator!= (const Direction_3< Kernel > &e) const
	Test for inequality.
Direction_3< Kernel >	operator- () const
	The direction opposite to d.
Vector_3< Kernel >	vector () const
	returns a vector that has the same direction as d.
Direction_3< Kernel >	transform (const Aff_transformation_3< Kernel > &t) const
	returns the direction obtained by applying t on d.

Member Function Documentation

delta()

template<typename Kernel >

Kernel::RT CGAL::Direction_3< Kernel >::delta

(

int

i

)

const

returns values, such that d== Direction_3<Kernel>(delta(0),delta(1),delta(2)).

Precondition

\( 0 \leq i \leq2\).