cgal/Packages/Planar_map/include/CGAL/Pm_simple_point_location.h

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// Copyright (c) 1997 Tel-Aviv University (Israel).
// 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.
//
// $Source$
// $Revision$ $Date$
// $Name$
//
// Author(s) : Eyal Flato <flato@math.tau.ac.il>
#ifndef CGAL_PM_SIMPLE_POINT_LOCATION_H
#define CGAL_PM_SIMPLE_POINT_LOCATION_H
#include <CGAL/Pm_point_location_base.h>
#include <CGAL/Planar_map_2/Pm_traits_wrap_2.h>
#include <list>
CGAL_BEGIN_NAMESPACE
template <class Planar_map_>
class Pm_simple_point_location : public Pm_point_location_base<Planar_map_> {
public:
typedef Planar_map_ Planar_map;
typedef typename Planar_map::Traits Traits;
typedef Pm_point_location_base<Planar_map> Base;
typedef Pm_simple_point_location<Planar_map> Self;
typedef typename Planar_map::Traits_wrap Traits_wrap;
typedef typename Planar_map::Locate_type Locate_type;
typedef typename Planar_map::Face_handle Face_handle;
typedef typename Planar_map::Ccb_halfedge_circulator
Ccb_halfedge_circulator;
typedef typename Planar_map::Halfedge_handle Halfedge_handle;
typedef typename Planar_map::Halfedge_iterator Halfedge_iterator;
typedef typename Planar_map::Halfedge Halfedge;
typedef typename Planar_map::Vertex_handle Vertex_handle;
typedef typename Traits::Point Point;
typedef typename Traits::X_curve X_curve;
typedef Pm_bounding_box_base<Planar_map> Bounding_box;
typedef typename Base::Halfedge_handle_iterator Halfedge_handle_iterator;
typedef typename Base::Token Token;
typedef std::list<Halfedge_handle> Halfedges_list;
public:
Pm_simple_point_location() :
Pm_point_location_base<Planar_map>(),
traits(0) {}
Pm_simple_point_location(Planar_map* _pm,Traits_wrap* _traits) :
Pm_point_location_base<Planar_map>(),traits(_traits),pm(_pm) {}
void init(Planar_map& pmp, Traits& tr)
{
pm = &pmp;
traits = (Traits_wrap*)(&tr);
}
void insert(Halfedge_handle, const X_curve &)
{
}
void find_relevant_halfedges(const Point& p, Halfedges_list &relevant) const
{
// find whether p is on a halfedge
typename Planar_map::Halfedge_iterator hit;
for (hit = pm->halfedges_begin(); hit != pm->halfedges_end(); ++hit)
{
if (traits->point_in_x_range(hit->curve(),p))
{
relevant.push_back(hit);
}
}
}
Halfedge_handle locate(const Point& p, Locate_type& lt) const
{
// find whether p is on a vertex
typename Planar_map::Vertex_iterator vit;
for (vit=pm->vertices_begin(); vit!=pm->vertices_end(); ++vit)
{
if (traits->point_equal(p,vit->point()) )
{
lt = Planar_map::VERTEX;
Halfedge_handle h(vit->incident_halfedges());
return h;
}
}
Halfedges_list relevant_halfedges;
find_relevant_halfedges(p, relevant_halfedges);
// find whether p is on a halfedge
typename Halfedges_list::const_iterator hit;
for (hit=relevant_halfedges.begin(); hit!=relevant_halfedges.end(); ++hit)
{
if (traits->point_in_x_range((*hit)->curve(),p) &&
traits->curve_compare_y_at_x(p, (*hit)->curve()) == EQUAL)
{
lt = Planar_map::EDGE;
return *hit;
}
}
lt = Planar_map::UNBOUNDED_FACE;
Locate_type temp;
Halfedge_handle h;
h = vertical_ray_shoot(p, temp, true, relevant_halfedges);
if( temp != Planar_map::UNBOUNDED_FACE )
{
if (temp == Planar_map::VERTEX) {
//since h points at the vertex and is the first
h=h->twin(); //halfedge after the ray clockwise! then the face
//is to its _right_ (maybe the specs will change in
//the future)
}
if ( !(h->face()->is_unbounded()) )
lt=Planar_map::FACE;
return h;
}
else //==the vertical ray shoot returned the halfedges_end() iterator.
{
if (pm->unbounded_face()->holes_begin() ==
pm->unbounded_face()->holes_end() ) //an empty map
return h; //return halfedges_end()
else {
//- returns a halfedge on an inner ccb of the unbounded face
typename Planar_map::Holes_iterator hot =
pm->unbounded_face()->holes_begin();
return (*hot);
}
}
}
Halfedge_handle locate(const Point& p, Locate_type& lt)
{
((Bounding_box*)get_bounding_box())->insert(p);
Halfedge_handle h=((cPLp)this)->locate(p,lt);
if (!((Bounding_box*)get_bounding_box())->locate(p,lt,h))
h=((cPLp)this)->locate(p,lt);
return h;
}
Halfedge_handle vertical_ray_shoot(const Point& p, Locate_type& lt,
bool up) const
{
Halfedges_list relevant_halfedges;
find_relevant_halfedges(p, relevant_halfedges);
return vertical_ray_shoot(p, lt, up, relevant_halfedges);
}
Halfedge_handle vertical_ray_shoot(const Point& p, Locate_type& lt, bool up,
const Halfedges_list &relevant_halfedges)
const
{
typename Planar_map::Halfedge_iterator it, eit, closest_edge;
bool first = false;
Comparison_result point_above_under, res;
Comparison_result curve_above_under;
bool in_x_range;
it = pm->halfedges_begin();
eit = pm->halfedges_end();
closest_edge = eit;
lt = Planar_map::EDGE;
// set the flags for comparison acording to the ray
// direction (up/down)
if (up)
{
point_above_under = SMALLER;
curve_above_under = LARGER;
}
else
{
point_above_under = LARGER;
curve_above_under = SMALLER;
}
typename Halfedges_list::const_iterator rel_it;
for (rel_it = relevant_halfedges.begin();
rel_it != relevant_halfedges.end();)
{
it = *rel_it;
in_x_range = traits->point_in_x_range(it->curve(), p);
if (in_x_range)
res = traits->curve_compare_y_at_x(p, it->curve());
if (in_x_range && (res == point_above_under))
{
if (!first)
{
closest_edge = it;
first = true;
}
else
{
if (traits->curves_compare_y_at_x(closest_edge->curve(),
it->curve(), p) ==
curve_above_under)
{
closest_edge = it;
}
}
}
if (in_x_range && res == EQUAL &&
traits->curve_is_vertical(it->curve()))
{
// The vertical ray shoot is not including p itself,
// thus we are interested only in vertical curves that
// extend upwards
// In this case the Locate type is always EDGE
// Remark: This treatment was originally written in the walk PL.
if (up &&
traits->point_is_right_top(traits->curve_righttop_most
(it->curve()), p) ||
! up &&
traits->point_is_left_low(traits->curve_leftlow_most
(it->curve()), p))
/*
x x
| |
p=x or p
|
x
*/
{
lt = Planar_map::EDGE;
if (up==traits->point_is_left_low(it->target()->point(),
it->source()->point()))
return it;
else
return it->twin();
}
}
++rel_it;
++rel_it;
}
// if we didn't find any edge above p then it is the empty face
if (!first) {
lt=Planar_map::UNBOUNDED_FACE;
Halfedge_handle h=pm->halfedges_end();
return h; //==NULL
}
// if the closest point is a vertex then find the first clockwise
// edge from the vertical segment
typename Planar_map::Vertex_handle v = pm->vertices_end();
bool maybe_vertical=false; // BUG fix (Oren)
if ( traits->point_equal_x(closest_edge->target()->point(), p) )
{
v = closest_edge->target();
maybe_vertical=true; // BUG fix (Oren)
}
if ( traits->point_equal_x( closest_edge->source()->point(), p) )
{
if (!maybe_vertical ||
traits->point_is_right_top(closest_edge->target()->point(),
closest_edge->source()->point())==up)
// BUG fix (Oren)
v = closest_edge->source();
/*
special care for the vertical cases:
x p
|
x and x
|
p x
*/
}
//if (closest_is_vertex)
if (v != pm->vertices_end())
{
lt=Planar_map::VERTEX;
if (up)
closest_edge = find_lowest(v,traits, false);
else
closest_edge = find_lowest(v,traits, true);
}
Halfedge_handle h;
if (lt==Planar_map::VERTEX)
{
h=closest_edge;
}
else if (up)
{
// return the edge that is going from right to left
// such that p is to the left of this edge
if ( traits->point_is_right( closest_edge->source()->point(),
closest_edge->target()->point()) )
{
h=closest_edge; //source is right of the target
}
else
h=closest_edge->twin();
}
else
{
if ( traits->point_is_left( closest_edge->source()->point(),
closest_edge->target()->point()) )
h=closest_edge;
else
h=closest_edge->twin();
}
return h;
}
Halfedge_handle vertical_ray_shoot(const Point& p, Locate_type& lt, bool up)
{
/* Make sure the source point is in the bounding box on the output */
((Bounding_box*)get_bounding_box())->insert(p);
Halfedge_handle h=((cPLp)this)->vertical_ray_shoot(p,lt,up);
/* Apply the bounding box on the output */
if (!((Bounding_box*)get_bounding_box())->vertical_ray_shoot(p,lt,up,h))
{
h=((cPLp)this)->vertical_ray_shoot(p,lt,up);
CGAL_assertion(lt!=Planar_map::UNBOUNDED_FACE);
}
return h;
}
void split_edge(const X_curve &,
Halfedge_handle, Halfedge_handle,
const X_curve &, const X_curve &)
{
}
void merge_edge(const X_curve &, const X_curve &,
Halfedge_handle,
const X_curve &)
{
}
void remove_edge(Halfedge_handle)
{
}
void remove_edge(const Halfedge_handle_iterator &,
const Halfedge_handle_iterator &)
{
}
void clear()
{
}
void update(const Halfedge_handle_iterator &,
const Halfedge_handle_iterator &,
const Token & token)
{ token.rebuild_bounding_box(this); }
public:
inline const Bounding_box* get_bounding_box() const
{return pm->get_bounding_box();}
inline const Traits* get_traits() const {return traits;}
protected:
Halfedge_handle find_lowest(Vertex_handle v,Traits_wrap *traits,
bool highest) const
//find the first halfedge pointing at v, when going clockwise
//if highest==true - start from 12 oclock, else start from 6 oclock
{
Halfedge_handle lowest_left = pm->halfedges_end();
Halfedge_handle lowest_right = pm->halfedges_end();
Halfedge_handle vertical_up = pm->halfedges_end();
Halfedge_handle vertical_down = pm->halfedges_end();
typename Planar_map::Halfedge_around_vertex_circulator first =
v->incident_halfedges();
typename Planar_map::Halfedge_around_vertex_circulator curr = first;
do {
if ( traits->point_is_left(curr->source()->point(), v->point()))
{
if (lowest_left == pm->halfedges_end())
lowest_left = curr;
if (traits->curves_compare_y_at_x_left(curr->curve(),
lowest_left->curve(),
v->point())==SMALLER)
lowest_left = curr;
}
if ( traits->point_is_right(curr->source()->point(),
v->point()) )
{
if (lowest_right == pm->halfedges_end())
lowest_right = curr;
if (traits->curves_compare_y_at_x_right(curr->curve(),
lowest_right->curve(),
v->point())==LARGER
)
lowest_right = curr;
}
if (traits->curve_is_vertical(curr->curve())) {
if (traits->compare_xy(v->point(),
curr->source()->point())==LARGER)
//debug
//{ std::cout << "vertical up = " << curr->curve() << std::endl;
vertical_up=curr;
//}//enddebug
if (traits->compare_xy(v->point(),
curr->source()->point())==SMALLER)
//debug
//{ std::cout << "vertical down = " << curr->curve() << std::endl;
vertical_down=curr;
//}//enddebug
}
} while (++curr != first);
/*
vertical_down
|
v <- lowest_right
'v'
lowest_left-> ^
|
vertical_up
*/
if (!highest) {
if (lowest_left!= pm->halfedges_end())
return lowest_left;
else
if (vertical_down!= pm->halfedges_end())
return vertical_down;
else
return lowest_right;
}
else { //down
if (lowest_right!=pm->halfedges_end())
return lowest_right;
else
if (vertical_up!=pm->halfedges_end())
return vertical_up;
else
return lowest_left;
}
}
#ifdef CGAL_PM_DEBUG
void debug(){}
#endif
protected:
typedef const Self* cPLp;
protected:
Planar_map* pm;
Traits_wrap* traits;
};
CGAL_END_NAMESPACE
#endif //CGAL_PM_NAIVE_POINT_LOCATION_H