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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/v6.1.1/Intersections_2/include/CGAL/Intersections_2/Ray_2_Ray_2.h $
// $Id: include/CGAL/Intersections_2/Ray_2_Ray_2.h 08b27d3db14 $
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s) : Geert-Jan Giezeman
#ifndef CGAL_INTERSECTIONS_2_RAY_2_RAY_2_H
#define CGAL_INTERSECTIONS_2_RAY_2_RAY_2_H
#include <CGAL/Ray_2.h>
#include <CGAL/Segment_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_Ray_2_pair {
public:
enum Intersection_results {NO_INTERSECTION, POINT, SEGMENT, RAY, UNKNOWN};
Ray_2_Ray_2_pair(typename K::Ray_2 const *ray1,
typename K::Ray_2 const *ray2)
: _ray1(ray1), _ray2(ray2) {}
Intersection_results intersection_type() const;
typename K::Point_2 intersection_point() const;
typename K::Segment_2 intersection_segment() const;
typename K::Ray_2 intersection_ray() const;
protected:
typename K::Ray_2 const* _ray1;
typename K::Ray_2 const * _ray2;
mutable Intersection_results _result = UNKNOWN;
mutable typename K::Point_2 _intersection_point, _other_point;
};
template <class K>
inline
typename K::Boolean
do_intersect(const typename K::Ray_2& r1,
const typename K::Ray_2& r2,
const K&)
{
typedef Ray_2_Ray_2_pair<K> pair_t;
pair_t pair(&r1, &r2);
return pair.intersection_type() != pair_t::NO_INTERSECTION;
}
template <class K>
typename Ray_2_Ray_2_pair<K>::Intersection_results
Ray_2_Ray_2_pair<K>::intersection_type() const
{
if (_result!=UNKNOWN)
return _result;
// The non const this pointer is used to cast away const.
// if (!do_overlap(_ray1->bbox(), _ray2->bbox()))
// return NO_INTERSECTION;
const typename K::Line_2 &l1 = _ray1->supporting_line();
const typename K::Line_2 &l2 = _ray2->supporting_line();
Line_2_Line_2_pair<K> linepair(&l1, &l2);
switch ( linepair.intersection_type()) {
case Line_2_Line_2_pair<K>::NO_INTERSECTION:
_result = NO_INTERSECTION;
return _result;
case Line_2_Line_2_pair<K>::POINT:
_intersection_point = linepair.intersection_point();
_result = (_ray1->collinear_has_on(_intersection_point)
&& _ray2->collinear_has_on(_intersection_point) )
? POINT : NO_INTERSECTION;
return _result;
case Line_2_Line_2_pair<K>::LINE:
{
//typedef typename K::RT RT;
const typename K::Vector_2 &dir1 = _ray1->direction().to_vector();
const typename K::Vector_2 &dir2 = _ray2->direction().to_vector();
if (CGAL_NTS abs(dir1.x()) > CGAL_NTS abs(dir1.y())) {
typedef typename K::FT FT;
if (dir1.x() > FT(0)) {
if (dir2.x() > FT(0)) {
_intersection_point =
(_ray1->source().x() < _ray2->source().x())
? _ray2->source() : _ray1->source();
_result = RAY;
return _result;
} else {
if (_ray1->source().x() > _ray2->source().x()) {
_result = NO_INTERSECTION;
return _result;
}
if (_ray1->source().x() == _ray2->source().x()) {
_intersection_point = _ray1->source();
_result = POINT;
return _result;
}
_result = SEGMENT;
return _result;
}
} else {
if (dir2.x() < FT(0)) {
_intersection_point =
(_ray1->source().x() > _ray2->source().x())
? _ray2->source() : _ray1->source();
_result = RAY;
return _result;
} else {
if (_ray1->source().x() < _ray2->source().x()) {
_result = NO_INTERSECTION;
return _result;
}
if (_ray1->source().x() == _ray2->source().x()) {
_intersection_point = _ray1->source();
_result = POINT;
return _result;
}
_result = SEGMENT;
return _result;
}
}
} else {
typedef typename K::FT FT;
if (dir1.y() > FT(0)) {
if (dir2.y() > FT(0)) {
_intersection_point =
(_ray1->source().y() < _ray2->source().y())
? _ray2->source() : _ray1->source();
_result = RAY;
return _result;
} else {
if (_ray1->source().y() > _ray2->source().y()) {
_result = NO_INTERSECTION;
return _result;
}
if (_ray1->source().y() == _ray2->source().y()) {
_intersection_point = _ray1->source();
_result = POINT;
return _result;
}
_result = SEGMENT;
return _result;
}
} else {
if (dir2.y() < FT(0)) {
_intersection_point =
(_ray1->source().y() > _ray2->source().y())
? _ray2->source() : _ray1->source();
_result = RAY;
return _result;
} else {
if (_ray1->source().y() < _ray2->source().y()) {
_result = NO_INTERSECTION;
return _result;
}
if (_ray1->source().y() == _ray2->source().y()) {
_intersection_point = _ray1->source();
_result = POINT;
return _result;
}
_result = SEGMENT;
return _result;
}
}
}
}
default:
CGAL_kernel_assertion(false); // should not be reached:
return _result;
}
}
template <class K>
typename K::Point_2
Ray_2_Ray_2_pair<K>::intersection_point() const
{
if (_result==UNKNOWN)
intersection_type();
CGAL_kernel_assertion(_result == POINT);
return _intersection_point;
}
template <class K>
typename K::Segment_2
Ray_2_Ray_2_pair<K>::intersection_segment() const
{
typedef typename K::Segment_2 Segment_2;
if (_result==UNKNOWN)
intersection_type();
CGAL_kernel_assertion(_result == SEGMENT);
return Segment_2(_ray1->source(), _ray2->source());
}
template <class K>
typename K::Ray_2
Ray_2_Ray_2_pair<K>::intersection_ray() const
{
typedef typename K::Ray_2 Ray_2;
if (_result==UNKNOWN)
intersection_type();
CGAL_kernel_assertion(_result == RAY);
return Ray_2(_intersection_point, _ray1->direction());
}
template <class K>
typename CGAL::Intersection_traits
<K, typename K::Ray_2, typename K::Ray_2>::result_type
intersection(const typename K::Ray_2 &ray1,
const typename K::Ray_2 &ray2,
const K&)
{
typedef Ray_2_Ray_2_pair<K> is_t;
is_t ispair(&ray1, &ray2);
switch (ispair.intersection_type()) {
case is_t::NO_INTERSECTION:
default:
return intersection_return<typename K::Intersect_2, typename K::Ray_2, typename K::Ray_2>();
case is_t::POINT:
return intersection_return<typename K::Intersect_2, typename K::Ray_2, typename K::Ray_2>(ispair.intersection_point());
case is_t::SEGMENT:
return intersection_return<typename K::Intersect_2, typename K::Ray_2, typename K::Ray_2>(ispair.intersection_segment());
case is_t::RAY:
return intersection_return<typename K::Intersect_2, typename K::Ray_2, typename K::Ray_2>(ispair.intersection_ray());
}
}
} // namespace internal
} // namespace Intersections
CGAL_INTERSECTION_FUNCTION_SELF(Ray_2, 2)
CGAL_DO_INTERSECT_FUNCTION_SELF(Ray_2, 2)
} // namespace CGAL
#endif // CGAL_INTERSECTIONS_2_RAY_2_RAY_2_H
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