snc_intersection.h

来自「CGAL is a collaborative effort of severa」· C头文件 代码 · 共 356 行

// Copyright (c) 1997-2002  Max-Planck-Institute Saarbruecken (Germany).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you may redistribute it under
// the terms of the Q Public License version 1.0.
// See the file LICENSE.QPL distributed with CGAL.
//
// 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.
//
// $Source: /CVSROOT/CGAL/Packages/Nef_3/include/CGAL/Nef_3/SNC_intersection.h,v $
// $Revision: 1.22.2.1 $ $Date: 2004/12/08 19:30:48 $
// $Name:  $
//
// Author(s)     : Michael Seel       <[e-mail]>
//                 Peter Hachenberger <[e-mail]> 
#ifndef CGAL_SNC_INTERSECTION_H
#define CGAL_SNC_INTERSECTION_H

#include <CGAL/basic.h>

#undef CGAL_NEF_DEBUG
#define CGAL_NEF_DEBUG 37
#include <CGAL/Nef_2/debug.h>

CGAL_BEGIN_NAMESPACE

template < class Node, class Object>
struct Project_halfedge_point {
  typedef Node         argument_type;
  typedef Object       result_type;
  Object& operator()( Node& x) const   { 
    return x.source()->source()->point();
    /* a Point_3& reference must be returned by D.point() */
  }
  const Object& operator()( const Node& x) const   { 
    return x.source()->source()->point(); 
    /* a Point_3& reference must be returned by D.point() */
  }
};

template<typename SNC_structure_>
class SNC_intersection : public SNC_const_decorator<SNC_structure_> {
  // TODO: granados: is it really necessary to inherit from the decorator?

  typedef SNC_structure_                     SNC_structure;
  typedef SNC_intersection<SNC_structure>    Self;
  typedef SNC_const_decorator<SNC_structure> Base;
  //  typedef SNC_const_decorator<SNC_structure> SNC_const_decorator;

  typedef typename SNC_structure::SHalfedge               SHalfedge;
  typedef typename SNC_structure::Halfedge_handle         Halfedge_handle;
  typedef typename SNC_structure::Halffacet_const_handle  
                                  Halffacet_const_handle;
  typedef typename SNC_structure::SHalfedge_const_handle  SHalfedge_const_handle;
  typedef typename SNC_structure::SHalfloop_const_handle  SHalfloop_const_handle;
  typedef typename SNC_structure::SHalfedge_around_facet_const_circulator 
                                  SHalfedge_around_facet_const_circulator;
  typedef typename SNC_structure::Halffacet_cycle_const_iterator
                                  Halffacet_cycle_const_iterator;

  typedef typename SNC_structure::Point_3        Point_3;
  typedef typename SNC_structure::Vector_3       Vector_3;
  typedef typename SNC_structure::Segment_3      Segment_3;
  typedef typename SNC_structure::Line_3         Line_3;
  typedef typename SNC_structure::Ray_3          Ray_3;
  typedef typename SNC_structure::Plane_3        Plane_3;
  typedef typename SNC_structure::Triangle_3     Triangle_3;

 public:

  SNC_intersection() : Base() {}
  SNC_intersection(const SNC_structure& W) : Base(W) {}

  bool does_contain_internally(const Segment_3& s, const Point_3& p) const {
    if(!s.has_on(p))
      return false;
    Comparison_result r1 = compare_xyz(s.source(),p);
    Comparison_result r2 = compare_xyz(s.target(),p);
    return (r1 == opposite(r2));
  }

  bool does_contain_internally( Halffacet_const_handle f, 
				const Point_3& p) const {
    if( !plane(f).has_on(p))
      return false;
    return (locate_point_in_halffacet( p, f) == CGAL::ON_BOUNDED_SIDE); 
  }

  bool does_contain_on_boundary( Halffacet_const_handle f, const Point_3& p) const {
    typedef Project_halfedge_point
      < SHalfedge, const Point_3> Project;
    typedef Circulator_project
      < SHalfedge_around_facet_const_circulator, Project, 
      const Point_3&, const Point_3*> Circulator;
    Halffacet_cycle_const_iterator fc = f->facet_cycles_begin();
    CGAL_assertion(fc.is_shalfedge());
    if (fc.is_shalfedge() ) {
      SHalfedge_const_handle se(fc);
      SHalfedge_around_facet_const_circulator hfc(se);
      Circulator c(hfc), cp(c), cend(c);
      do {
	c++;
	CGAL_NEF_TRACEN("contained on edge "<<Segment_3( *c, *cp)<<"? "<<
	       Segment_3( *c, *cp).has_on(p));
	if( Segment_3( *c, *cp).has_on(p))
	  return true;
	cp++;
      }
      while( c != cend); 
    } 
    Halffacet_cycle_const_iterator fe = f->facet_cycles_end();
    ++fc;
    CGAL_For_all(fc, fe) {
      if (fc.is_shalfloop() ) { 
	SHalfloop_const_handle l(fc);
	CGAL_NEF_TRACEN("isolated point on "<<l->incident_sface()->center_vertex()->point()<<"? ");
	if( l->incident_sface()->center_vertex()->point() == p)
	  return true;
      } 
      else if (fc.is_shalfedge() ) {
	SHalfedge_const_handle se(fc);
	SHalfedge_around_facet_const_circulator hfc(se);
	Circulator c(hfc), cp(c), cend(c);
	do {
	  c++;
	  CGAL_NEF_TRACEN("contained on edge "<<Segment_3( *c, *cp)<<"? "<<
		 Segment_3( *c, *cp).has_on(p));
	  if( Segment_3( *c, *cp).has_on(p))
	    return true;
	  cp++;
	} 
	while( c != cend);
      }
      else 
	CGAL_assertion_msg(0, "Damn wrong handle.");
    }
    return false;
  }
  
#ifdef LINE3_LINE3_INTERSECTION
  
  bool does_intersect_internally( const Segment_3& s1, 
				  const Segment_3& s2, 
				  Point_3& p) const  {
    CGAL_NEF_TRACEN("does intersect internally with  LINE3_LINE3_INTERSECTION");
    if ( s1.is_degenerate() || s2.is_degenerate())
      /* the segment is degenerate so there is not internal intersection */
      return false;
    if ( s1.has_on(s2.source()) || s1.has_on(s2.target()) ||
	 s2.has_on(s1.source()) || s2.has_on(s1.target()))
      /* the segments does intersect at one endpoint */
      return false;
    Object o = intersection(Line_3(ray), Line_3(s)); 
    if ( !CGAL::assign(p, o))
      return false;
    return( does_contain_internally( s, p));
  }

#else // LINE3_LINE3_INTERSECTION

  bool does_intersect_internally( const Segment_3& s1, 
				  const Segment_3& s2, 
				  Point_3& p) const {
    if(s2.has_on(s1.target())) 
      return false;
    return (does_intersect_internally(Ray_3(s1.source(), s1.target()), s2, p)
      && s1.has_on(p));
    
  }

  bool does_intersect_internally( const Ray_3& s1, 
				  const Segment_3& s2, 
				  Point_3& p) const {
    CGAL_NEF_TRACEN("does intersect internally without  LINE3_LINE3_INTERSECTION");
    if ( s1.is_degenerate() || s2.is_degenerate())
      // the segment is degenerate so there is not internal intersection 
      return false;
    if ( orientation( s1.source(), s1.point(1), s2.source(), s2.target()) 
	 != COPLANAR)
      // the segments doesn't define a plane
      return false;
    if ( s1.has_on(s2.source()) || s1.has_on(s2.target()) ||
	 s2.has_on(s1.source()))
      // the segments does intersect at one endpoint 
      return false;
    Line_3 ls1(s1), ls2(s2);
    if ( ls1.direction() ==  ls2.direction() ||
	 ls1.direction() == -ls2.direction() )
      // the segments are parallel 
      return false;
    Vector_3 vs1(s1.to_vector()), vs2(s2.to_vector()), 
      vt(cross_product( vs1, vs2)), 
      ws1(cross_product( vt, vs1)), ws2(cross_product( vt, vs2));
    Plane_3 hs1( s1.source(), ws1);
    Object o = intersection(hs1, ls2);
    CGAL_assertion(CGAL::assign( p, o));
    // since line(s1) and line(s2) are not parallel they intersects in only
    //   one point 
    CGAL::assign( p ,o);
    return( s1.has_on(p) && s2.has_on(p));
  }
    
#endif // LINE3_LINE3_INTERSECTION

  bool does_intersect( const Ray_3& r, const Triangle_3& tr,
		       Point_3& ip) const {
    // Intersection between an open ray and
    // a closed 2d-triangular region in the space
    CGAL_NEF_TRACEN("-> Intersection triangle - ray");
    CGAL_NEF_TRACEN(" -> Ray: "<<r);
    CGAL_NEF_TRACEN(" -> Triangle: "<<tr);
    CGAL_assertion( !r.is_degenerate());
    Plane_3 h( tr.supporting_plane());
    CGAL_assertion( !h.is_degenerate());
    if( h.has_on( r.source()))
      return false;
    Object o = intersection( h, r);
    if( !CGAL::assign( ip, o))
      return false;
    CGAL_NEF_TRACEN(" -> intersection point: "<<ip);
    return tr.has_on(ip);
  }

  bool does_intersect( const Segment_3& s, const Triangle_3& tr,
		       Point_3& ip) const {
    // Intersection between a open segment and
    // a closed 2d-triangular region in the space
    CGAL_NEF_TRACEN("-> Intersection triangle - segment");
    CGAL_NEF_TRACEN(" -> Segment: "<<s);
    CGAL_NEF_TRACEN(" -> Triangle: "<<tr);
    CGAL_assertion( !s.is_degenerate());
    Plane_3 h( tr.supporting_plane());
    CGAL_assertion( !h.is_degenerate());
    if( h.has_on( s.source()) || h.has_on( s.target()))
      return false;
    Object o = intersection( h, s);
    if( !CGAL::assign( ip, o))
      return false;
    CGAL_NEF_TRACEN(" -> intersection point: "<<ip);
    return tr.has_on(ip);
  }

  bool does_intersect_internally( const Ray_3& ray,
				  Halffacet_const_handle f,
				  Point_3& p) const { 
    CGAL_NEF_TRACEN("-> Intersection facet - ray");
    Plane_3 h( f->plane());
    CGAL_NEF_TRACEN("-> facet's plane: " << h);
    CGAL_NEF_TRACEN("-> a point on the plane: " << h.point());
    CGAL_NEF_TRACEN("-> ray: " << ray);
    if( ray.is_degenerate())
      /* no possible internal intersection */
      return false;
    if( h.has_on( ray.source()))
      /* no possible internal intersection */
	return false;
    Object o = intersection( h, ray);
    if( !CGAL::assign( p, o))
      return false;
    CGAL_NEF_TRACEN( "-> intersection point: " << p );
    CGAL_NEF_TRACEN( "-> point in facet interior? "<<does_contain_internally( f, p));
    return does_contain_internally( f, p);
  }

  bool does_intersect_internally( const Segment_3& seg,
				  Halffacet_const_handle f,
				  Point_3& p) const { 
    CGAL_NEF_TRACEN("-> Intersection facet - segment");
    Plane_3 h( plane(f));
    CGAL_NEF_TRACEN("-> facet's plane: " << h);
    CGAL_NEF_TRACEN("-> a point on the plane: " << h.point());
    CGAL_NEF_TRACEN("-> segment: " << seg);
    if( seg.is_degenerate())
      /* no possible internal intersection */
      return false;
    if( h.has_on( seg.source()) || h.has_on(seg.target()))
      /* no possible internal intersection */
      return false;
    Object o = intersection( h, seg);
    if( !CGAL::assign( p, o))
      return false;
    CGAL_NEF_TRACEN( "-> intersection point: " << p );
    CGAL_NEF_TRACEN( "-> point in facet interior? "<<does_contain_internally( f, p));
    return( does_contain_internally( f, p));
  }

  Bounded_side locate_point_in_halffacet( const Point_3& p, 
					  Halffacet_const_handle f) const {
    typedef Project_halfedge_point
      < SHalfedge, const Point_3> Project;
    typedef Circulator_project
      < SHalfedge_around_facet_const_circulator, Project, 
      const Point_3&, const Point_3*> Circulator;
    typedef Container_from_circulator<Circulator> Container;

    Plane_3 h(plane(f));
    CGAL_assertion(h.has_on(p));
    Halffacet_cycle_const_iterator fc = f->facet_cycles_begin();
    Bounded_side outer_bound_pos(CGAL::ON_BOUNDARY);
    if (fc.is_shalfedge() ) {
      SHalfedge_const_handle se(fc);
      SHalfedge_around_facet_const_circulator hfc(se);
      Circulator c(hfc);
      Container ct(c);
      CGAL_assertion( !is_empty_range(ct.begin(), ct.end()));
      outer_bound_pos = bounded_side_3(ct.begin(), ct.end(), p, h);
    } 
    else 
      CGAL_assertion_msg(0, "is facet first cycle a SHalfloop?");
    if( outer_bound_pos != CGAL::ON_BOUNDED_SIDE )
      return outer_bound_pos;
    /* The point p is not in the relative interior of the outer face cycle
       so it is not necesary to know the possition of p with respect to the 
       inner face cycles */
    Halffacet_cycle_const_iterator fe = f->facet_cycles_end();
    ++fc;
    if( fc == fe )
      return outer_bound_pos;
    Bounded_side inner_bound_pos(CGAL::ON_BOUNDARY);
    CGAL_For_all(fc, fe) {
      if (fc.is_shalfloop() ) {
	SHalfloop_const_handle l(fc);
        if(l->incident_sface()->center_vertex()->point() == p )
	  inner_bound_pos = CGAL::ON_BOUNDARY;
	else
	  inner_bound_pos = CGAL::ON_UNBOUNDED_SIDE;
      } 
      else if (fc.is_shalfedge() ) {
	SHalfedge_const_handle se(fc);
	SHalfedge_around_facet_const_circulator hfc(se);
	Circulator c(hfc);
	Container ct(c);
	CGAL_assertion( !is_empty_range(ct.begin(), ct.end()));
        inner_bound_pos = bounded_side_3( ct.begin(), ct.end(), 
					  p, h.opposite());
      } 
      else 
	CGAL_assertion_msg(0, "Damn wrong handle.");
      if( inner_bound_pos != CGAL::ON_UNBOUNDED_SIDE )
	return opposite(inner_bound_pos);
      /* At this point the point p belongs to relative interior of the facet's
	 outer cycle, and its possition is completely known when it belongs
	 to the clousure of any inner cycle */
    }
    return CGAL::ON_BOUNDED_SIDE;
  }
}; // SNC_intersection

CGAL_END_NAMESPACE

#endif //CGAL_SNC_INTERSECTION_H