// 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); 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; either version 3 of the License, // or (at your option) any later version. // // 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. // // $URL$ // $Id$ // // // Author(s) : Geert-Jan Giezeman #ifndef CGAL_RAY_2_LINE_2_INTERSECTION_H #define CGAL_RAY_2_LINE_2_INTERSECTION_H #include #include #include #include #include #include #include namespace CGAL { namespace internal { template 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 inline bool do_intersect( const typename K::Ray_2 &p1, const typename K::Line_2 &p2, const K&) { typedef Ray_2_Line_2_pair pair_t; pair_t pair(&p1, &p2); return pair.intersection_type() != pair_t::NO_INTERSECTION; } template typename Intersection_traits ::result_type intersection(const typename K::Ray_2 &ray, const typename K::Line_2 &line, const K&) { typedef Ray_2_Line_2_pair is_t; is_t ispair(&ray, &line); switch (ispair.intersection_type()) { case is_t::NO_INTERSECTION: default: return intersection_return(); case is_t::POINT: return intersection_return(ispair.intersection_point()); case is_t::RAY: return intersection_return(ray); } } template inline typename Intersection_traits ::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 inline bool do_intersect( const typename K::Line_2 &p1, const typename K::Ray_2 &p2, const K&) { typedef Ray_2_Line_2_pair pair_t; pair_t pair(&p2, &p1); return pair.intersection_type() != pair_t::NO_INTERSECTION; } template typename Ray_2_Line_2_pair::Intersection_results Ray_2_Line_2_pair::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 linepair(&l1, _line); switch ( linepair.intersection_type()) { case Line_2_Line_2_pair::NO_INTERSECTION: _result = NO_INTERSECTION; break; case Line_2_Line_2_pair::POINT: _intersection_point = linepair.intersection_point(); _result = (_ray->collinear_has_on(_intersection_point) ) ? POINT : NO_INTERSECTION; break; case Line_2_Line_2_pair::LINE: _result = RAY; break; } return _result; } template typename K::Point_2 Ray_2_Line_2_pair::intersection_point() const { if (!_known) intersection_type(); CGAL_kernel_assertion(_result == POINT); return _intersection_point; } template typename K::Ray_2 Ray_2_Line_2_pair::intersection_ray() const { if (!_known) intersection_type(); CGAL_kernel_assertion(_result == RAY); return *_ray; } } // namespace internal CGAL_INTERSECTION_FUNCTION(Ray_2, Line_2, 2) CGAL_DO_INTERSECT_FUNCTION(Ray_2, Line_2, 2) } //namespace CGAL #endif