mirror of https://github.com/CGAL/cgal
274 lines
7.1 KiB
C++
274 lines
7.1 KiB
C++
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// Copyright (c) 2000 Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
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// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
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// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
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// and Tel-Aviv University (Israel). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; version 2.1 of the License.
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// See the file LICENSE.LGPL distributed with CGAL.
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//
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// Licensees holding a valid commercial license may use this file in
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// accordance with the commercial license agreement provided with the software.
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//
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// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// $Source$
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// $Revision$ $Date$
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// $Name$
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//
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// Author(s) : Geert-Jan Giezeman
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#ifndef CGAL_SEGMENT_2_TRIANGLE_2_INTERSECTION_H
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#define CGAL_SEGMENT_2_TRIANGLE_2_INTERSECTION_H
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#include <CGAL/Segment_2.h>
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#include <CGAL/Triangle_2.h>
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#include <CGAL/Point_2.h>
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#include <CGAL/Line_2.h>
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#include <CGAL/kernel_assertions.h>
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#include <CGAL/number_utils.h>
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#include <CGAL/Straight_2.h>
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#include <CGAL/Object.h>
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CGAL_BEGIN_NAMESPACE
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namespace CGALi {
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template <class K>
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class Segment_2_Triangle_2_pair {
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public:
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enum Intersection_results {NO, POINT, SEGMENT};
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Segment_2_Triangle_2_pair() ;
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Segment_2_Triangle_2_pair(typename K::Segment_2 const *seg,
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typename K::Triangle_2 const *trian);
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~Segment_2_Triangle_2_pair() {}
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Intersection_results intersection_type() const;
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bool intersection(typename K::Point_2 &result) const;
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bool intersection(typename K::Segment_2 &result) const;
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protected:
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typename K::Segment_2 const * _seg;
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typename K::Triangle_2 const * _trian;
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mutable bool _known;
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mutable Intersection_results _result;
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mutable typename K::Point_2 _intersection_point;
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mutable typename K::Point_2 _other_point;
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};
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template <class K>
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inline bool do_intersect(
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const typename CGAL_WRAP(K)::Segment_2 &p1,
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const typename CGAL_WRAP(K)::Triangle_2 &p2,
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const K&)
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{
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typedef Segment_2_Triangle_2_pair<K> pair_t;
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pair_t pair(&p1, &p2);
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return pair.intersection_type() != pair_t::NO;
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}
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template <class K>
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Segment_2_Triangle_2_pair<K>::
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Segment_2_Triangle_2_pair()
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{
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_known = false;
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_seg = 0;
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_trian = 0;
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}
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template <class K>
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Segment_2_Triangle_2_pair<K>::
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Segment_2_Triangle_2_pair(typename K::Segment_2 const *seg,
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typename K::Triangle_2 const *trian)
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{
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_known = false;
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_seg = seg;
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_trian = trian;
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}
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template <class K>
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typename Segment_2_Triangle_2_pair<K>::Intersection_results
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Segment_2_Triangle_2_pair<K>::intersection_type() const
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{
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if (_known)
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return _result;
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// The non const this pointer is used to cast away const.
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_known = true;
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Straight_2_<K> straight(*_seg);
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typedef typename K::Line_2 Line_2;
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Line_2 l(_trian->vertex(0), _trian->vertex(1));
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if (l.oriented_side(_trian->vertex(2)) == ON_POSITIVE_SIDE) {
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straight.cut_right_off(
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Line_2(_trian->vertex(0), _trian->vertex(1)));
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straight.cut_right_off(
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Line_2(_trian->vertex(1), _trian->vertex(2)));
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straight.cut_right_off(
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Line_2(_trian->vertex(2), _trian->vertex(0)));
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} else {
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straight.cut_right_off(
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Line_2(_trian->vertex(2), _trian->vertex(1)));
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straight.cut_right_off(
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Line_2(_trian->vertex(1), _trian->vertex(0)));
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straight.cut_right_off(
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Line_2(_trian->vertex(0), _trian->vertex(2)));
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}
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switch (straight.current_state()) {
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case Straight_2_<K>::EMPTY:
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_result = NO;
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return _result;
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case Straight_2_<K>::POINT: {
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straight.current(_intersection_point);
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_result = POINT;
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return _result;
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}
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case Straight_2_<K>::SEGMENT: {
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typename K::Segment_2 seg;
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straight.current(seg);
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_intersection_point = seg.source();
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_other_point = seg.target();
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_result = SEGMENT;
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return _result;
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}
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default: // should not happen.
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CGAL_kernel_assertion_msg(false, "Internal CGAL error.");
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_result = NO;
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return _result;
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}
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}
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template <class K>
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bool
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Segment_2_Triangle_2_pair<K>::
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intersection(typename K::Point_2 &result) const
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{
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if (!_known)
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intersection_type();
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if (_result != POINT)
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return false;
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result = _intersection_point;
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return true;
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}
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template <class K>
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bool
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Segment_2_Triangle_2_pair<K>::
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intersection(typename K::Segment_2 &result) const
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{
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typedef typename K::Segment_2 Segment_2;
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if (!_known)
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intersection_type();
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if (_result != SEGMENT)
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return false;
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result = Segment_2(_intersection_point, _other_point);
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return true;
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}
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template <class K>
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Object
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intersection(const typename CGAL_WRAP(K)::Segment_2 &seg,
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const typename CGAL_WRAP(K)::Triangle_2&tr,
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const K&)
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{
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typedef Segment_2_Triangle_2_pair<K> is_t;
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is_t ispair(&seg, &tr);
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switch (ispair.intersection_type()) {
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case is_t::NO:
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default:
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return Object();
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case is_t::POINT: {
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typename K::Point_2 pt;
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ispair.intersection(pt);
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return make_object(pt);
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}
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case is_t::SEGMENT: {
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typename K::Segment_2 iseg;
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ispair.intersection(iseg);
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return make_object(iseg);
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}
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}
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}
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template <class K>
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Object
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intersection(const typename CGAL_WRAP(K)::Triangle_2&tr,
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const typename CGAL_WRAP(K)::Segment_2 &seg,
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const K& k)
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{
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return CGALi::intersection(seg, tr, k);
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}
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template <class K>
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class Triangle_2_Segment_2_pair
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: public Segment_2_Triangle_2_pair<K> {
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public:
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Triangle_2_Segment_2_pair(
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typename K::Triangle_2 const *trian,
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typename K::Segment_2 const *seg) :
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Segment_2_Triangle_2_pair<K>(seg, trian) {}
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};
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template <class K>
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inline bool do_intersect(
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const typename CGAL_WRAP(K)::Triangle_2 &p1,
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const typename CGAL_WRAP(K)::Segment_2 &p2,
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const K&)
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{
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typedef Triangle_2_Segment_2_pair<K> pair_t;
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pair_t pair(&p1, &p2);
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return pair.intersection_type() != pair_t::NO;
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}
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} // namespace CGALi
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template <class K>
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inline Object
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intersection(const Segment_2<K> &seg, const Triangle_2<K> &tr)
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{
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typedef typename K::Intersect_2 Intersect;
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return Intersect()(seg, tr);
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}
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template <class K>
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inline Object
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intersection(const Triangle_2<K> &tr, const Segment_2<K> &seg)
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{
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typedef typename K::Intersect_2 Intersect;
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return Intersect()(seg, tr);
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}
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template <class K>
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inline bool
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do_intersect(const Segment_2<K> &seg, const Triangle_2<K> &tr)
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{
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typedef typename K::Do_intersect_2 Do_intersect;
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return Do_intersect()(seg, tr);
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}
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template <class K>
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inline bool
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do_intersect(const Triangle_2<K> &tr, const Segment_2<K> &seg)
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{
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typedef typename K::Do_intersect_2 Do_intersect;
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return Do_intersect()(seg, tr);
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}
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CGAL_END_NAMESPACE
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#endif
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