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Fix Circle_2 -- Bbox_2/Iso_rectangle_2 intersection 

Bbox_2 is inherently inexact as it is double-based. Thus, Bbox_2 should
use its conversion to Iso_rectangle_2 (a kernel type) and not the other way
around, otherwise we are doing FT --> double --> FT and losing precision.
This commit is contained in:
Mael Rouxel-Labbé 2019-05-20 10:06:14 +02:00
parent b322f685d4
commit ad1fbbd242
3 changed files with 104 additions and 137 deletions
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33
Intersections_2/include/CGAL/Intersections_2/Bbox_2_Circle_2.h
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@ -26,21 +26,46 @@
#include <CGAL/Bbox_2.h>
#include <CGAL/Circle_2.h>
#include <CGAL/Intersections_2/internal/Bbox_2_Circle_2_do_intersect.h>
#include <CGAL/Intersections_2/Circle_2_Iso_rectangle_2.h>
namespace CGAL {
namespace Intersections {
namespace internal {
template <class K>
bool do_intersect(const CGAL::Bbox_2& bbox,
const typename K::Circle_2& circle,
const K&)
{
return do_intersect_circle_iso_rectangle_2(circle, bbox, K());
}
template <class K>
bool do_intersect(const typename K::Circle_2& circle,
const CGAL::Bbox_2& bbox,
const K&)
{
return do_intersect_circle_iso_rectangle_2(circle, bbox, K());
}
} // namespace internal
} // namespace Intersections
template<typename K>
bool do_intersect(const CGAL::Bbox_2& a,
const Circle_2<K>& b) {
const Circle_2<K>& b)
{
return K().do_intersect_2_object()(a, b);
}
template<typename K>
bool do_intersect(const Circle_2<K>& a,
const CGAL::Bbox_2& b) {
const CGAL::Bbox_2& b)
{
return K().do_intersect_2_object()(a, b);
}
}
} // namespace CGAL
#endif // CGAL_INTERSECTIONS_2_BBOX_2_CIRCLE_2_H

82
Intersections_2/include/CGAL/Intersections_2/Circle_2_Iso_rectangle_2.h
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@ -23,30 +23,98 @@
#ifndef CGAL_INTERSECTIONS_2_ISO_RECTANGLE_2_CIRCLE_2_H
#define CGAL_INTERSECTIONS_2_ISO_RECTANGLE_2_CIRCLE_2_H
#include <CGAL/Iso_rectangle_2.h>
#include <CGAL/Circle_2.h>
#include <CGAL/Intersections_2/internal/Bbox_2_Circle_2_do_intersect.h>
#include <CGAL/Iso_rectangle_2.h>
#include <CGAL/Intersection_traits_2.h>
namespace CGAL {
namespace Intersections {
namespace internal {
// Circle_2 is not a disk, thus if the box is contained within the circle, there is no intersection.
template <class K>
bool do_intersect(const typename K::Iso_rectangle_2& bbox,
bool do_intersect_circle_iso_rectangle_2(const typename K::Circle_2& circle,
const typename K::Iso_rectangle_2& rec,
const K&)
{
typedef typename K::FT FT;
typedef typename K::Point_2 Point;
Point center = circle.center();
// Check that the minimum distance to the box is smaller than the radius, otherwise there is
// no intersection.
FT distance = FT(0);
if(center.x() < rec.xmin())
{
FT d = rec.xmin() - center.x();
distance += d * d;
}
else if(center.x() > rec.xmax())
{
FT d = center.x() - rec.xmax();
distance += d * d;
}
if(center.y() < rec.ymin())
{
FT d = rec.ymin() - center.y();
distance += d * d;
}
else if(center.y() > rec.ymax())
{
FT d = center.y() - rec.ymax();
distance += d * d;
}
// Note that with the way the distance above is computed, the distance is '0' if the box strictly
// contains the circle. But since we use '>', we don't exit
if(distance > circle.squared_radius())
return false;
// Check that the maximum distance between the center of the circle and the box is not (strictly)
// smaller than the radius of the center, otherwise the box is entirely contained.
distance = FT(0);
if(center.x() <= (rec.xmin() + rec.xmax()) / FT(2))
{
FT d = rec.xmax() - center.x();
distance += d * d;
}
else
{
FT d = center.x() - rec.xmin();
distance += d * d;
}
if(center.y() < (rec.ymin() + rec.ymax()) / FT(2))
{
FT d = rec.ymax() - center.y();
distance += d * d;
}
else
{
FT d = center.y() - rec.ymin();
distance += d * d;
}
return (distance >= circle.squared_radius());
}
template <class K>
bool do_intersect(const typename K::Iso_rectangle_2& rec,
const typename K::Circle_2& circle,
const K&)
{
return do_intersect_circle_box_2(circle, bbox, K());
return do_intersect_circle_iso_rectangle_2(circle, rec, K());
}
template <class K>
bool do_intersect(const typename K::Circle_2& circle,
const typename K::Iso_rectangle_2& bbox,
const typename K::Iso_rectangle_2& rec,
const K&)
{
return do_intersect_circle_box_2(circle, bbox, K());
return do_intersect_circle_iso_rectangle_2(circle, rec, K());
}
} // namespace internal

126
Intersections_2/include/CGAL/Intersections_2/internal/Bbox_2_Circle_2_do_intersect.h
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@ -1,126 +0,0 @@
// Copyright (c) 2018 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.
//
// $URL$
// $Id$
// SPDX-License-Identifier: LGPL-3.0+
//
//
// Author(s) : Andreas Fabri
#ifndef CGAL_INTERNAL_INTERSECTIONS_2_BBOX_2_CIRCLE_2_DO_INTERSECT_H
#define CGAL_INTERNAL_INTERSECTIONS_2_BBOX_2_CIRCLE_2_DO_INTERSECT_H
#include <CGAL/Circle_2.h>
#include <CGAL/Bbox_2.h>
#include <CGAL/number_utils.h>
namespace CGAL {
namespace Intersections {
namespace internal {
// Circle_2 is not a disk, thus if the box is contained within the circle, there is no intersection.
template <class K, class Box2>
bool do_intersect_circle_box_2(const typename K::Circle_2& circle,
const Box2& bbox,
const K&)
{
typedef typename K::FT FT;
typedef typename K::Point_2 Point;
Point center = circle.center();
// Check that the minimum distance to the box is smaller than the radius, otherwise there is
// no intersection.
FT distance = FT(0);
if(center.x() < FT(bbox.xmin()))
{
FT d = FT(bbox.xmin()) - center.x();
distance += d * d;
}
else if(center.x() > FT(bbox.xmax()))
{
FT d = center.x() - FT(bbox.xmax());
distance += d * d;
}
if(center.y() < FT(bbox.ymin()))
{
FT d = FT(bbox.ymin()) - center.y();
distance += d * d;
}
else if(center.y() > FT(bbox.ymax()))
{
FT d = center.y() - FT(bbox.ymax());
distance += d * d;
}
// Note that with the way the distance above is computed, the distance is '0' if the box strictly
// contains the circle. But since we use '>', we don't exit
if(distance > circle.squared_radius())
return false;
// Check that the maximum distance between the center of the circle and the box is not (strictly)
// smaller than the radius of the center, otherwise the box is entirely contained.
distance = FT(0);
if(center.x() <= FT(bbox.xmin() + bbox.xmax()) / FT(2))
{
FT d = FT(bbox.xmax()) - center.x();
distance += d * d;
}
else
{
FT d = center.x() - FT(bbox.xmin());
distance += d * d;
}
if(center.y() < FT(bbox.ymin() + bbox.ymax()) / FT(2))
{
FT d = FT(bbox.ymax()) - center.y();
distance += d * d;
}
else
{
FT d = center.y() - FT(bbox.ymin());
distance += d * d;
}
return (distance >= circle.squared_radius());
}
template <class K>
bool do_intersect(const CGAL::Bbox_2& bbox,
const typename K::Circle_2& circle,
const K&)
{
return do_intersect_circle_box_2(circle, bbox, K());
}
template <class K>
bool do_intersect(const typename K::Circle_2& circle,
const CGAL::Bbox_2& bbox,
const K&)
{
return do_intersect_circle_box_2(circle, bbox, K());
}
} // namespace internal
} // namespace Intersections
} // namespace CGAL
#endif // CGAL_INTERNAL_INTERSECTIONS_2_BBOX_2_CIRCLE_2_DO_INTERSECT_H