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// Copyright (c) 2003 INRIA Sophia-Antipolis (France).
// 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: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/next/Intersections_2/include/CGAL/Triangle_2_Triangle_2_do_intersect.h $
// $Id: Triangle_2_Triangle_2_do_intersect.h 67093 2012-01-13 11:22:39Z lrineau $
//
//
// Author(s) : Philippe Guigue
#ifndef CGAL_TRIANGLE_2_TRIANGLE_2_DO_INTERSECT_H
#define CGAL_TRIANGLE_2_TRIANGLE_2_DO_INTERSECT_H
#include <CGAL/Triangle_2.h>
namespace CGAL {
namespace internal {
template <class K>
bool intersection_test_vertex(const typename K::Point_2 * P1,
const typename K::Point_2 * Q1,
const typename K::Point_2 * R1,
const typename K::Point_2 * P2,
const typename K::Point_2 * Q2,
const typename K::Point_2 * R2,
const K & k ){
CGAL_kernel_precondition( k.orientation_2_object() (*P1,*Q1,*R1)
== POSITIVE);
CGAL_kernel_precondition( k.orientation_2_object() (*P2,*Q2,*R2)
== POSITIVE);
typename K::Orientation_2 orientation =
k.orientation_2_object();
if (orientation(*R2,*P2,*Q1) != NEGATIVE) {
if (orientation(*R2,*Q2,*Q1) != POSITIVE) {
if (orientation(*P1,*P2,*Q1) == POSITIVE)
return orientation(*P1,*Q2,*Q1) != POSITIVE;
return orientation(*P1,*P2,*R1) != NEGATIVE
&& orientation(*Q1,*R1,*P2) != NEGATIVE ;
}
return orientation(*P1,*Q2,*Q1) != POSITIVE
&& orientation(*R2,*Q2,*R1) != POSITIVE
&& orientation(*Q1,*R1,*Q2) != NEGATIVE ;
}
if (orientation(*R2,*P2,*R1) != NEGATIVE) {
if (orientation(*Q1,*R1,*R2) != NEGATIVE)
return orientation(*P1,*P2,*R1) != NEGATIVE;
return orientation(*Q1,*R1,*Q2) != NEGATIVE
&& orientation(*R2,*R1,*Q2) != NEGATIVE;
}
return false;
}
template <class K>
bool intersection_test_edge(const typename K::Point_2 * P1,
const typename K::Point_2 * Q1,
const typename K::Point_2 * R1,
const typename K::Point_2 * P2,
const typename K::Point_2 * Q2,
const typename K::Point_2 * R2,
const K & k ){
CGAL_kernel_precondition( k.orientation_2_object() (*P1,*Q1,*R1)
== POSITIVE);
CGAL_kernel_precondition( k.orientation_2_object() (*P2,*Q2,*R2)
== POSITIVE);
typename K::Orientation_2 orientation =
k.orientation_2_object();
if (orientation(*R2,*P2,*Q1) != NEGATIVE) {
if (orientation(*P1,*P2,*Q1) != NEGATIVE)
return orientation(*P1,*Q1,*R2) != NEGATIVE;
return orientation(*Q1,*R1,*P2) != NEGATIVE
&& orientation(*R1,*P1,*P2) != NEGATIVE;
}
if (orientation(*R2,*P2,*R1) != NEGATIVE)
return orientation(*P1,*P2,*R1) != NEGATIVE
&& ( orientation(*P1,*R1,*R2) != NEGATIVE
|| orientation(*Q1,*R1,*R2) != NEGATIVE ) ;
return false;
}
template <class K>
bool do_intersect(const typename K::Triangle_2 &t1,
const typename K::Triangle_2 &t2,
const K & k ){
CGAL_kernel_precondition( ! k.is_degenerate_2_object() (t1) );
CGAL_kernel_precondition( ! k.is_degenerate_2_object() (t2) );
typename K::Construct_vertex_2 vertex_on =
k.construct_vertex_2_object();
typename K::Orientation_2 orientation =
k.orientation_2_object();
typedef typename K::Point_2 Point_2;
const Point_2 & P1 = vertex_on(t1,0);
const Point_2 & Q1 = vertex_on(t1,1);
const Point_2 & R1 = vertex_on(t1,2);
const Point_2 & P2 = vertex_on(t2,0);
const Point_2 & Q2 = vertex_on(t2,1);
const Point_2 & R2 = vertex_on(t2,2);
const Point_2 * p1 = &P1;
const Point_2 * q1 = &Q1;
const Point_2 * r1 = &R1;
const Point_2 * p2 = &P2;
const Point_2 * q2 = &Q2;
const Point_2 * r2 = &R2;
if ( orientation(P1,Q1,R1) != POSITIVE ) {
q1 = &R1;;
r1 = &Q1;
}
if ( orientation(P2,Q2,R2) != POSITIVE ) {
q2 = &R2;
r2 = &Q2;
}
if ( orientation(*p2,*q2,*p1) != NEGATIVE ) {
if ( orientation(*q2,*r2,*p1) != NEGATIVE ) {
if ( orientation(*r2,*p2,*p1) != NEGATIVE ) return true;
return internal::intersection_test_edge(p1,q1,r1,p2,q2,r2,k);
}
if ( orientation(*r2,*p2,*p1) != NEGATIVE )
return internal::intersection_test_edge(p1,q1,r1,r2,p2,q2,k);
return internal::intersection_test_vertex(p1,q1,r1,p2,q2,r2,k);
}
if ( orientation(*q2,*r2,*p1) != NEGATIVE ) {
if ( orientation(*r2,*p2,*p1) != NEGATIVE )
return internal::intersection_test_edge(p1,q1,r1,q2,r2,p2,k);
return internal::intersection_test_vertex(p1,q1,r1,q2,r2,p2,k);
}
return internal::intersection_test_vertex(p1,q1,r1,r2,p2,q2,k);
}
} // namespace internal
template <class K>
inline bool do_intersect(const Triangle_2<K> &t1,
const Triangle_2<K> &t2)
{
typedef typename K::Do_intersect_2 Do_intersect;
return Do_intersect()(t1,t2);
}
} //namespace CGAL
#endif //CGAL_TRIANGLE_2_TRIANGLE_2_DO_INTERSECT_H
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