mirror of https://github.com/CGAL/cgal
399 lines
10 KiB
C
399 lines
10 KiB
C
// 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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// $URL$
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// $Id$
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//
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//
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// Author(s) : Geert-Jan Giezeman
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#include <CGAL/Segment_2.h>
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#include <CGAL/Triangle_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 <vector>
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#include <CGAL/Line_2_Line_2_intersection.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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struct Pointlist_2_rec_ {
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Pointlist_2_rec_ *next;
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typename K::Point_2 point;
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Oriented_side side;
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};
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template <class K>
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struct Pointlist_2_ {
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int size;
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Pointlist_2_rec_<K> *first;
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Pointlist_2_() ;
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~Pointlist_2_() ;
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};
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template <class K>
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class Triangle_2_Triangle_2_pair {
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public:
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enum Intersection_results {NO, POINT, SEGMENT, TRIANGLE, POLYGON};
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Triangle_2_Triangle_2_pair() ;
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Triangle_2_Triangle_2_pair(
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typename K::Triangle_2 const *trian1,
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typename K::Triangle_2 const *trian2) ;
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~Triangle_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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bool intersection(typename K::Triangle_2 &result) const;
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bool intersection(/*Polygon_2<R> &result*/) const;
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int vertex_count() const;
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typename K::Point_2 vertex(int i) const;
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protected:
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typename K::Triangle_2 const* _trian1;
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typename K::Triangle_2 const * _trian2;
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mutable bool _known;
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mutable Intersection_results _result;
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mutable Pointlist_2_<K> _pointlist;
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};
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// template <class R>
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// inline bool do_intersect(
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// const Triangle_2<R> &p1,
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// const Triangle_2<R> &p2)
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// {
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// typedef Triangle_2_Triangle_2_pair<R> 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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Pointlist_2_<K>::Pointlist_2_()
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{
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size = 0;
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first = 0;
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}
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template <class K>
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Pointlist_2_<K>::~Pointlist_2_()
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{
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Pointlist_2_rec_<K> *cur;
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for (int i=0; i<size; i++) {
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cur = first;
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first = cur->next;
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delete cur;
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}
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}
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template <class K>
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void _init_list(Pointlist_2_<K> &list,
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const typename K::Triangle_2 &trian)
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{
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// check on degeneracies of trian.
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if (!trian.is_degenerate()) {
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list.size = 3;
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list.first = 0;
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for (int i=0; i<3; i++) {
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Pointlist_2_rec_<K> *newrec =
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new Pointlist_2_rec_<K>;
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newrec->next = list.first;
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list.first = newrec;
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newrec->point = trian[i];
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}
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} else {
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// _not_implemented();
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CGAL_kernel_assertion(false);
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}
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}
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template <class K>
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void _cut_off(Pointlist_2_<K> &list,
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const typename K::Line_2 &cutter)
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{
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int i;
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int add = 0;
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Pointlist_2_rec_<K> *cur, *last=0, *newrec;
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for (i=0, cur = list.first; i<list.size; i++, cur = cur->next) {
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cur->side = cutter.oriented_side(cur->point);
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last = cur;
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}
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for (cur = list.first, i=0; i<list.size; i++, cur = cur->next) {
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if ((cur->side == ON_POSITIVE_SIDE
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&& last->side == ON_NEGATIVE_SIDE)
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|| (cur->side == ON_NEGATIVE_SIDE
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&& last->side == ON_POSITIVE_SIDE)) {
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// add a vertex after cur
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add++;
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typename K::Line_2 l(cur->point, last->point);
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newrec = new Pointlist_2_rec_<K>;
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newrec->next = last->next;
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last->next = newrec;
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newrec->side = ON_ORIENTED_BOUNDARY;
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Line_2_Line_2_pair<K> linepair(&cutter, &l);
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typename Line_2_Line_2_pair<K>::Intersection_results isr;
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isr = linepair.intersection_type();
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CGAL_kernel_assertion(isr == Line_2_Line_2_pair<K>::POINT);
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linepair.intersection(newrec->point);
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}
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last = cur;
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}
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CGAL_kernel_assertion(add <= 2);
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Pointlist_2_rec_<K> **curpt;
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curpt = &list.first;
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while (*curpt != 0) {
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cur = *curpt;
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if (cur->side == ON_NEGATIVE_SIDE) {
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add--;
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*curpt = cur->next;
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delete cur;
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} else {
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curpt = &cur->next;
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}
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}
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if (list.size == 2 && add == 1) {
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add = 0;
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cur = list.first;
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if (cur->side == ON_ORIENTED_BOUNDARY) {
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list.first = cur->next;
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delete cur;
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} else {
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last = cur;
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cur = cur->next;
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last->next = cur->next;
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delete cur;
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}
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}
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list.size += add;
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}
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template <class K>
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Triangle_2_Triangle_2_pair<K>::
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Triangle_2_Triangle_2_pair()
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{
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_trian1 = 0;
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_trian2 = 0;
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_known = false;
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}
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template <class K>
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Triangle_2_Triangle_2_pair<K>::
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Triangle_2_Triangle_2_pair(typename K::Triangle_2 const *trian1,
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typename K::Triangle_2 const *trian2)
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{
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_trian1 = trian1;
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_trian2 = trian2;
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_known = false;
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}
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template <class K>
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typename Triangle_2_Triangle_2_pair<K>::Intersection_results
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Triangle_2_Triangle_2_pair<K>::intersection_type() const
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{
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typedef typename K::Line_2 Line_2;
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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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if (!do_overlap(_trian1->bbox(), _trian2->bbox())) {
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_result = NO;
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return _result;
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}
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_init_list(_pointlist, *_trian1);
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if (_trian2->is_degenerate()) {
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// _not_implemented();
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CGAL_kernel_assertion(false);
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} else {
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Line_2 l(_trian2->vertex(0), _trian2->vertex(1));
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if (l.oriented_side(_trian2->vertex(2)) == ON_POSITIVE_SIDE) {
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// counterclockwise triangle
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_cut_off(_pointlist, l);
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l = Line_2(_trian2->vertex(1), _trian2->vertex(2));
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_cut_off(_pointlist, l);
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l = Line_2(_trian2->vertex(2), _trian2->vertex(0));
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_cut_off(_pointlist, l);
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} else {
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l = l.opposite();
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_cut_off(_pointlist, l);
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l = Line_2(_trian2->vertex(0), _trian2->vertex(2));
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_cut_off(_pointlist, l);
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l = Line_2(_trian2->vertex(2), _trian2->vertex(1));
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_cut_off(_pointlist, l);
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}
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}
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switch (_pointlist.size) {
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case 0:
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_result = NO;
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break;
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case 1:
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_result = POINT;
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break;
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case 2:
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_result = SEGMENT;
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break;
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case 3:
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_result = TRIANGLE;
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break;
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default:
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_result = POLYGON;
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}
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return _result;
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}
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template <class K>
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bool
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Triangle_2_Triangle_2_pair<K>::intersection(
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/* Polygon_2<R> &result */) const
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{
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if (!_known)
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intersection_type();
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if (_result != TRIANGLE && _result != POLYGON)
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return false;
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Pointlist_2_rec_<K> *cur;
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int i;
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for (i=0, cur = _pointlist.first;
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i<_pointlist.size;
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i++, cur = cur->next) {
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std::cout << to_double(cur->point.x()) << ' ';
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std::cout << to_double(cur->point.y()) << ' ';
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}
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std::cout << std::endl;
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return true;
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}
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template <class K>
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int
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Triangle_2_Triangle_2_pair<K>::vertex_count() const
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{
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CGAL_kernel_assertion(_known);
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return _pointlist.size;
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}
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template <class K>
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typename K::Point_2
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Triangle_2_Triangle_2_pair<K>::vertex(int n) const
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{
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CGAL_kernel_assertion(_known);
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CGAL_kernel_assertion(n >= 0 && n < _pointlist.size);
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Pointlist_2_rec_<K> *cur;
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int k;
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for (k=0, cur = _pointlist.first;
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k < n;
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k++, cur = cur->next) {
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}
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return cur->point;
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}
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template <class K>
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bool
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Triangle_2_Triangle_2_pair<K>::intersection(
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typename K::Triangle_2 &result) const
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{
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typedef typename K::Triangle_2 Triangle_2;
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if (!_known)
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intersection_type();
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if (_result != TRIANGLE)
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return false;
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result = Triangle_2(_pointlist.first->point,
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_pointlist.first->next->point,
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_pointlist.first->next->next->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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Triangle_2_Triangle_2_pair<K>::intersection(
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typename K::Segment_2 &seg) 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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seg = Segment_2(_pointlist.first->point,
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_pointlist.first->next->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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Triangle_2_Triangle_2_pair<K>::intersection(
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typename K::Point_2 &pt) 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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pt = _pointlist.first->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)::Triangle_2 &tr1,
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const typename CGAL_WRAP(K)::Triangle_2 &tr2,
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const K& k)
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{
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typedef Triangle_2_Triangle_2_pair<K> is_t;
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is_t ispair(&tr1, &tr2);
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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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case is_t::TRIANGLE: {
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typename K::Triangle_2 itr;
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ispair.intersection(itr);
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return make_object(itr);
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}
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case is_t::POLYGON: {
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typedef std::vector<typename K::Point_2> Container;
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Container points(ispair.vertex_count());
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for (int i =0; i < ispair.vertex_count(); i++) {
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points[i] = ispair.vertex(i);
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}
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return make_object(points);
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}
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}
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}
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} // namespace CGALi
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CGAL_END_NAMESPACE
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