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// Copyright (c) 2000 Utrecht University (The Netherlands),
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
// and Tel-Aviv University (Israel). All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/CGAL-3.6-branch/Intersections_2/include/CGAL/Ray_2_Line_2_intersection.h $
// $Id: Ray_2_Line_2_intersection.h 51456 2009-08-24 17:10:04Z spion $
//
//
// Author(s) : Geert-Jan Giezeman
#ifndef CGAL_RAY_2_LINE_2_INTERSECTION_H
#define CGAL_RAY_2_LINE_2_INTERSECTION_H
#include <CGAL/Line_2.h>
#include <CGAL/Ray_2.h>
#include <CGAL/Point_2.h>
#include <CGAL/kernel_assertions.h>
#include <CGAL/number_utils.h>
#include <CGAL/Object.h>
#include <CGAL/Line_2_Line_2_intersection.h>
CGAL_BEGIN_NAMESPACE
namespace internal {
template <class K>
class Ray_2_Line_2_pair {
public:
enum Intersection_results {NO_INTERSECTION, POINT, RAY};
Ray_2_Line_2_pair(typename K::Ray_2 const *ray,
typename K::Line_2 const *line)
: _ray(ray), _line(line), _known(false) {}
Intersection_results intersection_type() const;
typename K::Point_2 intersection_point() const;
typename K::Ray_2 intersection_ray() const;
protected:
typename K::Ray_2 const * _ray;
typename K::Line_2 const * _line;
mutable bool _known;
mutable Intersection_results _result;
mutable typename K::Point_2 _intersection_point;
};
template <class K>
inline bool do_intersect(
const typename K::Ray_2 &p1,
const typename K::Line_2 &p2)
{
typedef Ray_2_Line_2_pair<K> pair_t;
pair_t pair(&p1, &p2);
return pair.intersection_type() != pair_t::NO_INTERSECTION;
}
template <class K>
Object
intersection(const typename K::Ray_2 &ray,
const typename K::Line_2 &line,
const K&)
{
typedef Ray_2_Line_2_pair<K> is_t;
is_t ispair(&ray, &line);
switch (ispair.intersection_type()) {
case is_t::NO_INTERSECTION:
default:
return Object();
case is_t::POINT:
return make_object(ispair.intersection_point());
case is_t::RAY:
return make_object(ray);
}
}
template <class K>
inline
Object
intersection(const typename K::Line_2 &line,
const typename K::Ray_2 &ray,
const K& k)
{
return internal::intersection(ray, line, k);
}
template <class K>
inline bool do_intersect(
const typename K::Line_2 &p1,
const typename K::Ray_2 &p2,
const K&)
{
typedef Ray_2_Line_2_pair<K> pair_t;
pair_t pair(&p2, &p1);
return pair.intersection_type() != pair_t::NO_INTERSECTION;
}
template <class K>
typename Ray_2_Line_2_pair<K>::Intersection_results
Ray_2_Line_2_pair<K>::intersection_type() const
{
if (_known)
return _result;
// The non const this pointer is used to cast away const.
_known = true;
const typename K::Line_2 &l1 = _ray->supporting_line();
Line_2_Line_2_pair<K> linepair(&l1, _line);
switch ( linepair.intersection_type()) {
case Line_2_Line_2_pair<K>::NO_INTERSECTION:
_result = NO_INTERSECTION;
break;
case Line_2_Line_2_pair<K>::POINT:
_intersection_point = linepair.intersection_point();
_result = (_ray->collinear_has_on(_intersection_point) ) ?
POINT : NO_INTERSECTION;
break;
case Line_2_Line_2_pair<K>::LINE:
_result = RAY;
break;
}
return _result;
}
template <class K>
typename K::Point_2
Ray_2_Line_2_pair<K>::intersection_point() const
{
if (!_known)
intersection_type();
CGAL_kernel_assertion(_result == POINT);
return _intersection_point;
}
template <class K>
typename K::Ray_2
Ray_2_Line_2_pair<K>::intersection_ray() const
{
if (!_known)
intersection_type();
CGAL_kernel_assertion(_result == RAY);
return *_ray;
}
} // namespace internal
template <class K>
inline bool do_intersect(const Line_2<K> &p1, const Ray_2<K> &p2)
{
typedef typename K::Do_intersect_2 Do_intersect;
return Do_intersect()(p1, p2);
}
template <class K>
inline bool do_intersect(const Ray_2<K> &p2, const Line_2<K> &p1)
{
typedef typename K::Do_intersect_2 Do_intersect;
return Do_intersect()(p1, p2);
}
template <class K>
inline Object
intersection(const Line_2<K> &line, const Ray_2<K> &ray)
{
typedef typename K::Intersect_2 Intersect;
return Intersect()(ray, line);
}
template <class K>
inline Object
intersection(const Ray_2<K> &ray, const Line_2<K> &line)
{
typedef typename K::Intersect_2 Intersect;
return Intersect()(ray, line);
}
CGAL_END_NAMESPACE
#endif
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