mirror of https://github.com/CGAL/cgal
238 lines
8.7 KiB
C++
238 lines
8.7 KiB
C++
// Copyright (c) 2010 GeometryFactory (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.
|
|
//
|
|
// $URL$
|
|
// $Id$
|
|
//
|
|
//
|
|
// Author(s) : Sebastien Loriot
|
|
//
|
|
|
|
#ifndef CGAL_TRIANGLE_3_TRIANGLE_3_INTERSECTION_H
|
|
#define CGAL_TRIANGLE_3_TRIANGLE_3_INTERSECTION_H
|
|
|
|
#include <CGAL/Intersection_traits_3.h>
|
|
|
|
#include <boost/next_prior.hpp>
|
|
#include <list>
|
|
#include <vector>
|
|
#include <map>
|
|
|
|
namespace CGAL {
|
|
|
|
template <class K>
|
|
class Triangle_3;
|
|
|
|
namespace internal{
|
|
|
|
template <class Kernel>
|
|
void intersection_coplanar_triangles_cutoff(
|
|
const typename Kernel::Point_3& p,
|
|
const typename Kernel::Point_3& q,
|
|
const typename Kernel::Point_3& r,
|
|
const Kernel& k,
|
|
std::list<typename Kernel::Point_3>& inter_pts
|
|
)
|
|
{
|
|
if ( inter_pts.empty() ) return;
|
|
typedef typename std::list<typename Kernel::Point_3>::iterator Iterator;
|
|
typename Kernel::Coplanar_orientation_3 orient=k.coplanar_orientation_3_object();
|
|
typename Kernel::Construct_line_3 Line_3=k.construct_line_3_object();
|
|
//orient(p,q,r,r) is POSITIVE
|
|
std::map<const typename Kernel::Point_3*,Orientation> orientations;
|
|
for (Iterator it=inter_pts.begin();it!=inter_pts.end();++it)
|
|
orientations[ &(*it) ]=orient(p,q,r,*it);
|
|
|
|
int pt_added=0;
|
|
|
|
const typename Kernel::Point_3* prev = &(*boost::prior(inter_pts.end()));
|
|
Iterator stop = inter_pts.size() > 2 ? inter_pts.end() : boost::prior(inter_pts.end());
|
|
for (Iterator it=inter_pts.begin();it!=stop;++it)
|
|
{
|
|
const typename Kernel::Point_3& curr=*it;
|
|
Orientation or_prev=orientations[prev],or_curr=orientations[&curr];
|
|
if ( (or_prev==POSITIVE && or_curr==NEGATIVE) || (or_prev==NEGATIVE && or_curr==POSITIVE) )
|
|
{
|
|
typename Intersection_traits<Kernel, typename Kernel::Line_3,
|
|
typename Kernel::Line_3>
|
|
::result_type
|
|
obj = intersection(Line_3(p,q),Line_3(*prev,curr),k);
|
|
// assert "not empty"
|
|
CGAL_kernel_assertion(bool(obj));
|
|
const typename Kernel::Point_3* inter=intersect_get<typename Kernel::Point_3>(obj);
|
|
CGAL_kernel_assertion(inter!=NULL);
|
|
prev=&(* inter_pts.insert(it,*inter) );
|
|
orientations[prev]=COLLINEAR;
|
|
++pt_added;
|
|
}
|
|
prev=&(*it);
|
|
}
|
|
|
|
CGAL_kernel_assertion(pt_added<3);
|
|
Iterator it=inter_pts.begin();
|
|
while(it!=inter_pts.end())
|
|
{
|
|
if (orientations[&(*it)]==NEGATIVE)
|
|
inter_pts.erase(it++);
|
|
else
|
|
++it;
|
|
}
|
|
}
|
|
|
|
template <class K>
|
|
typename Intersection_traits<K, typename K::Triangle_3, typename K::Triangle_3>::result_type
|
|
intersection_coplanar_triangles(
|
|
const typename K::Triangle_3& t1,
|
|
const typename K::Triangle_3& t2,
|
|
const K& k)
|
|
{
|
|
const typename K::Point_3& p=t1.vertex(0),q=t1.vertex(1),r=t1.vertex(2);
|
|
|
|
std::list<typename K::Point_3> inter_pts;
|
|
inter_pts.push_back(t2.vertex(0));
|
|
inter_pts.push_back(t2.vertex(1));
|
|
inter_pts.push_back(t2.vertex(2));
|
|
|
|
//intersect t2 with the three half planes which intersection defines t1
|
|
intersection_coplanar_triangles_cutoff(p,q,r,k,inter_pts); //line pq
|
|
intersection_coplanar_triangles_cutoff(q,r,p,k,inter_pts); //line qr
|
|
intersection_coplanar_triangles_cutoff(r,p,q,k,inter_pts); //line rp
|
|
|
|
switch ( inter_pts.size() ) {
|
|
case 0:
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>();
|
|
case 1:
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>( * inter_pts.begin() );
|
|
case 2:
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>( k.construct_segment_3_object()(*inter_pts.begin(),
|
|
*boost::next(inter_pts.begin())) );
|
|
case 3:
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>( k.construct_triangle_3_object()(*inter_pts.begin(),
|
|
*boost::next(inter_pts.begin()),
|
|
*boost::prior(inter_pts.end())) );
|
|
default:
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>( std::vector<typename K::Point_3>(inter_pts.begin(),inter_pts.end()) );
|
|
}
|
|
}
|
|
|
|
template<typename K>
|
|
struct Triangle_Line_visitor {
|
|
typedef typename Intersection_traits<K, typename K::Triangle_3, typename K::Triangle_3 >
|
|
::result_type result_type;
|
|
|
|
result_type
|
|
operator()(const typename K::Point_3& p, const typename K::Segment_3& s) const {
|
|
if ( s.has_on(p) )
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>(p);
|
|
else
|
|
return result_type();
|
|
}
|
|
|
|
result_type
|
|
operator()(const typename K::Segment_3& s, const typename K::Point_3& p) const {
|
|
return operator()(p,s);
|
|
}
|
|
|
|
result_type
|
|
operator()(const typename K::Point_3& p1, const typename K::Point_3& p2) const {
|
|
if (p1==p2)
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>(p1);
|
|
else
|
|
return result_type();
|
|
}
|
|
|
|
result_type
|
|
operator()(const typename K::Segment_3& s1, const typename K::Segment_3& s2) const {
|
|
typename Intersection_traits<K, typename K::Segment_3, typename K::Segment_3>::result_type
|
|
v = intersection_collinear_segments(s1,s2,K());
|
|
|
|
if(v) {
|
|
if(const typename K::Segment_3* s = intersect_get<typename K::Segment_3>(v))
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>(*s);
|
|
if(const typename K::Point_3* p = intersect_get<typename K::Point_3>(v))
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>(*p);
|
|
}
|
|
|
|
return result_type();
|
|
}
|
|
};
|
|
|
|
template <class K>
|
|
typename Intersection_traits<K, typename K::Triangle_3, typename K::Triangle_3>::result_type
|
|
intersection(
|
|
const typename K::Triangle_3& t1,
|
|
const typename K::Triangle_3& t2,
|
|
const K& k)
|
|
{
|
|
CGAL_precondition(!t1.is_degenerate() && !t2.is_degenerate());
|
|
|
|
typename Intersection_traits<K, typename K::Plane_3, typename K::Plane_3>::result_type
|
|
v = internal::intersection(t1.supporting_plane(), t2.supporting_plane(), k);
|
|
|
|
if(!v) {
|
|
// empty plane plane intersection
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>();
|
|
}
|
|
|
|
if(intersect_get<typename K::Plane_3>(v)) {
|
|
//coplanar triangles
|
|
return intersection_coplanar_triangles(t1,t2,k);
|
|
}
|
|
|
|
if(const typename K::Line_3* line=intersect_get<typename K::Line_3>(v)) {
|
|
//The supporting planes of the triangles intersect along a line.
|
|
typedef
|
|
typename Intersection_traits<K, typename K::Triangle_3, typename K::Line_3>::result_type
|
|
Triangle_Line_Inter;
|
|
|
|
Triangle_Line_Inter inter1 = intersection_coplanar(t1,*line,k);
|
|
Triangle_Line_Inter inter2 = intersection_coplanar(t2,*line,k);
|
|
if(!inter1 || !inter2) {
|
|
// one of the intersection is empty
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>();
|
|
}
|
|
#if CGAL_INTERSECTION_VERSION < 2
|
|
// apply the binary visitor manually
|
|
Triangle_Line_visitor<K> vis;
|
|
if(const typename K::Point_3* p1 = intersect_get<typename K::Point_3>(inter1)) {
|
|
if(const typename K::Point_3* p2 = intersect_get<typename K::Point_3>(inter2)) {
|
|
return vis(*p1, *p2);
|
|
} else if(const typename K::Segment_3* s2 = intersect_get<typename K::Segment_3>(inter2)) {
|
|
return vis(*p1, *s2);
|
|
}
|
|
} else if(const typename K::Segment_3* s1 = intersect_get<typename K::Segment_3>(inter1)) {
|
|
if(const typename K::Point_3* p2 = intersect_get<typename K::Point_3>(inter2)) {
|
|
return vis(*s1, *p2);
|
|
} else if(const typename K::Segment_3* s2 = intersect_get<typename K::Segment_3>(inter2)) {
|
|
return vis(*s1, *s2);
|
|
}
|
|
}
|
|
#else
|
|
return boost::apply_visitor(Triangle_Line_visitor<K>(), *inter1, *inter2);
|
|
#endif
|
|
}
|
|
return intersection_return<typename K::Intersect_3, typename K::Triangle_3, typename K::Triangle_3>();
|
|
}
|
|
|
|
}//namespace internal
|
|
|
|
CGAL_INTERSECTION_FUNCTION_SELF(Triangle_3, 3)
|
|
|
|
} // namespace CGAL
|
|
|
|
|
|
|
|
|
|
#endif //CGAL_TRIANGLE_3_TRIANGLE_3_INTERSECTION_H
|