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// Copyright (c) 2000
// Utrecht University (The Netherlands),
// ETH Zurich (Switzerland),
// INRIA Sophia-Antipolis (France),
// Max-Planck-Institute Saarbruecken (Germany),
// and Tel-Aviv University (Israel). All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1/Intersections_2/include/CGAL/Intersections_2/Line_2_Ray_2.h $
// $Id: include/CGAL/Intersections_2/Line_2_Ray_2.h b26b07a1242 $
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s) : Geert-Jan Giezeman
#ifndef CGAL_INTERSECTIONS_2_LINE_2_RAY_2_H
#define CGAL_INTERSECTIONS_2_LINE_2_RAY_2_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/Intersections_2/Line_2_Line_2.h>
#include <CGAL/Intersection_traits_2.h>
namespace CGAL {
namespace Intersections {
namespace internal {
template <class K>
class Ray_2_Line_2_pair {
public:
enum Intersection_results {NO_INTERSECTION, POINT, RAY, UNKNOWN};
typedef typename K::FT FT;
Ray_2_Line_2_pair(typename K::Ray_2 const *ray,
typename K::Line_2 const *line)
: _ray(ray), _line(line),
_intersection_point(K().construct_point_2_object()(ORIGIN))
{}
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 Intersection_results _result = UNKNOWN;
mutable typename K::Point_2 _intersection_point;
};
template <class K>
inline
typename K::Boolean
do_intersect(const typename K::Ray_2& r,
const typename K::Line_2& l,
const K&)
{
typedef Ray_2_Line_2_pair<K> pair_t;
pair_t pair(&r, &l);
return pair.intersection_type() != pair_t::NO_INTERSECTION;
}
template <class K>
inline
typename K::Boolean
do_intersect(const typename K::Line_2& l,
const typename K::Ray_2& r,
const K& k)
{
return do_intersect(r, l, k);
}
template <class K>
typename Intersection_traits
<K, typename K::Ray_2, typename K::Line_2>::result_type
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 intersection_return<typename K::Intersect_2, typename K::Ray_2, typename K::Line_2>();
case is_t::POINT:
return intersection_return<typename K::Intersect_2, typename K::Ray_2, typename K::Line_2>(ispair.intersection_point());
case is_t::RAY:
return intersection_return<typename K::Intersect_2, typename K::Ray_2, typename K::Line_2>(ray);
}
}
template <class K>
inline
typename Intersection_traits
<K, typename K::Line_2, typename K::Ray_2>::result_type
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>
typename Ray_2_Line_2_pair<K>::Intersection_results
Ray_2_Line_2_pair<K>::intersection_type() const
{
if (_result != UNKNOWN)
return _result;
// The non const this pointer is used to cast away const.
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:
default:
_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 (_result == UNKNOWN)
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 (_result == UNKNOWN)
intersection_type();
CGAL_kernel_assertion(_result == RAY);
return *_ray;
}
} // namespace internal
} // namespace Intersections
CGAL_INTERSECTION_FUNCTION(Ray_2, Line_2, 2)
CGAL_DO_INTERSECT_FUNCTION(Ray_2, Line_2, 2)
} //namespace CGAL
#endif
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