CGAL 6.1  2D and 3D Linear Geometry Kernel

#include <CGAL/Plane_3.h>
An object h
of the data type Plane_3
is an oriented plane in the threedimensional Euclidean space \( \E^3\).
It is defined by the set of points with Cartesian coordinates \( (x,y,z)\) that satisfy the plane equation
\[h :\; a\, x +b\, y +c\, z + d = 0.\]
The plane splits \( \E^3\) in a positive and a negative side. A point p
with Cartesian coordinates \( (px, py, pz)\) is on the positive side of h
, iff \( a\, px +b\, py +c\, pz + d > 0\). It is on the negative side, iff \( a\, px +b\, py\, +c\, pz + d < 0\).
Kernel::Plane_3
Creation  
Plane_3 (const Kernel::RT &a, const Kernel::RT &b, const Kernel::RT &c, const Kernel::RT &d)  
creates a plane h defined by the equation \( a\, px +b\, py +c\, pz + d = 0\).  
Plane_3 (const Point_3< Kernel > &p, const Point_3< Kernel > &q, const Point_3< Kernel > &r)  
creates a plane h passing through the points p , q and r .  
Plane_3 (const Point_3< Kernel > &p, const Vector_3< Kernel > &v)  
introduces a plane h that passes through point p and that is orthogonal to v .  
Plane_3 (const Point_3< Kernel > &p, const Direction_3< Kernel > &d)  
introduces a plane h that passes through point p and that has as an orthogonal direction equal to d .  
Plane_3 (const Line_3< Kernel > &l, const Point_3< Kernel > &p)  
introduces a plane h that is defined through the three points l.point(0) , l.point(1) and p .  
Plane_3 (const Ray_3< Kernel > &r, const Point_3< Kernel > &p)  
introduces a plane h that is defined through the three points r.point(0) , r.point(1) and p .  
Plane_3 (const Segment_3< Kernel > &s, const Point_3< Kernel > &p)  
introduces a plane h that is defined through the three points s.source() , s.target() and p .  
Plane_3 (const Circle_3< Kernel > &c)  
introduces a plane h that is defined as the plane containing the circle.  
Operations  
bool  operator== (const Plane_3< Kernel > &h2) const 
Test for equality: two planes are equal, iff they have a non empty intersection and the same orientation.  
bool  operator!= (const Plane_3< Kernel > &h2) const 
Test for inequality.  
Kernel::RT  a () const 
returns the first coefficient of h .  
Kernel::RT  b () const 
returns the second coefficient of h .  
Kernel::RT  c () const 
returns the third coefficient of h .  
Kernel::RT  d () const 
returns the fourth coefficient of h .  
Line_3< Kernel >  perpendicular_line (const Point_3< Kernel > &p) const 
returns the line that is perpendicular to h and that passes through point p .  
Point_3< Kernel >  projection (const Point_3< Kernel > &p) const 
returns the orthogonal projection of p on h .  
Plane_3< Kernel >  opposite () const 
returns the plane with opposite orientation.  
Point_3< Kernel >  point () const 
returns an arbitrary point on h .  
Vector_3< Kernel >  orthogonal_vector () const 
returns a vector that is orthogonal to h and that is directed to the positive side of h .  
Direction_3< Kernel >  orthogonal_direction () const 
returns the direction that is orthogonal to h and that is directed to the positive side of h .  
Vector_3< Kernel >  base1 () const 
returns a vector orthogonal to orthogonal_vector() .  
Vector_3< Kernel >  base2 () const 
returns a vector that is both orthogonal to base1() , and to orthogonal_vector() , and such that the result of orientation( point(), point() + base1(), point()+base2(), point() + orthogonal_vector() ) is positive.  
2D Conversion  
The following functions provide conversion between a plane and CGAL's twodimensional space. The transformation is affine, but not necessarily an isometry. This means, the transformation preserves combinatorics, but not distances.  
Point_2< Kernel >  to_2d (const Point_3< Kernel > &p) const 
returns the image point of the projection of p under an affine transformation, which maps h onto the \( xy\)plane, with the \( z\)coordinate removed.  
Point_3< Kernel >  to_3d (const Point_2< Kernel > &p) const 
returns a point q , such that to_2d( to_3d( p )) is equal to p .  
Predicates  
Oriented_side  oriented_side (const Point_3< Kernel > &p) const 
returns either ON_ORIENTED_BOUNDARY, or the constant ON_POSITIVE_SIDE, or the constant ON_NEGATIVE_SIDE, determined by the position of p relative to the oriented plane h .  
Convenience Boolean Functions  
bool  has_on (const Point_3< Kernel > &p) const 
bool  has_on_positive_side (const Point_3< Kernel > &p) const 
bool  has_on_negative_side (const Point_3< Kernel > &p) const 
bool  has_on (const Line_3< Kernel > &l) const 
bool  has_on (const Circle_3< Kernel > &l) const 
bool  is_degenerate () const 
Plane h is degenerate, if the coefficients a , b , and c of the plane equation are zero.  
Miscellaneous  
Plane_3< Kernel >  transform (const Aff_transformation_3< Kernel > &t) const 
returns the plane obtained by applying t on a point of h and the orthogonal direction of h .  
CGAL::Plane_3< Kernel >::Plane_3  (  const Kernel::RT &  a, 
const Kernel::RT &  b,  
const Kernel::RT &  c,  
const Kernel::RT &  d  
) 
creates a plane h
defined by the equation \( a\, px +b\, py +c\, pz + d = 0\).
Notice that h
is degenerate if \( a = b = c = 0\).
Exact_predicates_inexact_constructions_kernel
.CGAL::Plane_3< Kernel >::Plane_3  (  const Point_3< Kernel > &  p, 
const Point_3< Kernel > &  q,  
const Point_3< Kernel > &  r  
) 
creates a plane h
passing through the points p
, q
and r
.
The plane is oriented such that p
, q
and r
are oriented in a positive sense (that is counterclockwise) when seen from the positive side of h
. Notice that h
is degenerate if the points are collinear.
CGAL::Plane_3< Kernel >::Plane_3  (  const Circle_3< Kernel > &  c  ) 
introduces a plane h
that is defined as the plane containing the circle.
Exact_predicates_inexact_constructions_kernel
.Kernel::RT CGAL::Plane_3< Kernel >::a  (  )  const 
returns the first coefficient of h
.
Exact_predicates_inexact_constructions_kernel
.Kernel::RT CGAL::Plane_3< Kernel >::b  (  )  const 
returns the second coefficient of h
.
Exact_predicates_inexact_constructions_kernel
.Kernel::RT CGAL::Plane_3< Kernel >::c  (  )  const 
returns the third coefficient of h
.
Exact_predicates_inexact_constructions_kernel
.Kernel::RT CGAL::Plane_3< Kernel >::d  (  )  const 
returns the fourth coefficient of h
.
Exact_predicates_inexact_constructions_kernel
.Plane_3< Kernel > CGAL::Plane_3< Kernel >::opposite  (  )  const 
returns the plane with opposite orientation.
Exact_predicates_inexact_constructions_kernel
.Direction_3< Kernel > CGAL::Plane_3< Kernel >::orthogonal_direction  (  )  const 
returns the direction that is orthogonal to h
and that is directed to the positive side of h
.
Exact_predicates_inexact_constructions_kernel
.Vector_3< Kernel > CGAL::Plane_3< Kernel >::orthogonal_vector  (  )  const 
returns a vector that is orthogonal to h
and that is directed to the positive side of h
.
Exact_predicates_inexact_constructions_kernel
.