dust3d/thirdparty/cgal/CGAL-4.13/include/CGAL/Hyperbola_2.h

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// Copyright (c) 2003,2004 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
// 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: GPL-3.0+
//
//
// Author(s) : Menelaos Karavelas <mkaravel@iacm.forth.gr>
#ifndef CGAL_HYPERBOLA_2_H
#define CGAL_HYPERBOLA_2_H
#include <CGAL/license/Apollonius_graph_2.h>
#include <CGAL/enum.h>
#include <CGAL/determinant.h>
#include <CGAL/Apollonius_site_2.h>
#include <CGAL/Kernel_traits.h>
namespace CGAL {
template < class Gt >
class Hyperbola_2
{
public:
typedef Gt Geom_traits;
typedef typename Gt::Site_2 Site_2;
typedef typename Gt::Segment_2 Segment_2;
typedef typename Gt::Point_2 Point_2;
typedef typename Gt::FT FT;
#if 0
typedef typename Kernel_traits<Point>::Kernel Kernel;
typedef CGAL::Apollonius_site_2<Kernel> Site_2;
typedef typename Kernel::Segment_2 Segment_2;
typedef Point Point_2;
typedef typename Kernel::FT FT;
#endif
// typedef typename R::RT FT;
// typedef double FT;
// typedef CGAL::Point_2< Cartesian<double> > Point_2;
// typedef CGAL::Segment_2< Cartesian< double > > Segment_2;
protected:
FT STEP;
Point_2 f1, f2;
FT r;
Point_2 o;
inline
Point_2 lchain(const FT &t) const
{
std::vector< Point_2 > p = compute_points(t);
if ( right(p[0]) ) return p[1];
return p[0];
}
inline
Point_2 rchain(const FT &t) const
{
std::vector< Point_2 > p = compute_points(t);
if ( right(p[0]) ) return p[0];
return p[1];
}
inline
FT norm2(const Point_2& p) const
{
return (CGAL::square(p.x()) + CGAL::square(p.y()));
}
inline
FT distance2(const Point_2& p1, const Point_2& p2) const
{
FT dx = p1.x()-p2.x();
FT dy = p1.y()-p2.y();
return (CGAL::square(dx) + CGAL::square(dy));
}
inline
FT distance(const Point_2& p1, const Point_2& p2) const
{
return CGAL::sqrt( distance2(p1, p2) );
}
void compute_origin()
{
FT dx = f2.x() - f1.x();
FT dy = f2.y() - f1.y();
FT a = CGAL::sqrt(CGAL::square(dx) + CGAL::square(dy));
FT t = (FT(1) + r / a) / FT(2);
o = Point_2(dx * t + f1.x(), dy * t + f1.y());
}
std::vector< Point_2 > compute_points(const FT &d) const {
FT d1 = distance(o, f1) + d;
FT d2 = distance(o, f2) + d;
d1 *= d1;
d2 *= d2;
Point_2 df = Point_2(f2.x() - f1.x(), f2.y()-f1.y());
std::vector< Point_2 > p;
if ( CGAL::is_negative(d) ) return p;
if ( CGAL::is_zero(df.x()) ) {
FT y = (d1 - d2 + norm2(f2) - norm2(f1)) / (FT(2) * df.y());
FT D = d1 - CGAL::square(y - f1.y());
D = CGAL::abs(D);
FT x1 = CGAL::sqrt(D) + f1.x();
FT x2 = -CGAL::sqrt(D) + f1.x();
p.push_back(Point_2(x1, y));
p.push_back(Point_2(x2, y));
return p;
}
FT gamma = (d1 - d2 + norm2(f2) - norm2(f1)) / (FT(2) * df.x());
FT gamma1 = gamma - f1.x();
FT beta = df.y() / df.x();
FT a = FT(1) + CGAL::square(beta);
FT b = -FT(2) * (gamma1 * beta + f1.y());
FT c = CGAL::square(f1.y()) + CGAL::square(gamma1) - d1;
FT D = CGAL::square(b) - FT(4) * a * c;
D = CGAL::abs(D);
FT y1 = (-b + CGAL::sqrt(D)) / (FT(2) * a);
FT y2 = (-b - CGAL::sqrt(D)) / (FT(2) * a);
FT x1 = gamma - beta * y1;
FT x2 = gamma - beta * y2;
p.push_back(Point_2(x1, y1));
p.push_back(Point_2(x2, y2));
return p;
}
bool right(const Point_2& p) const
{
return
CGAL::is_negative( determinant<FT>(f1.x(), f1.y(), 1,
f2.x(), f2.y(), 1,
p.x(), p.y(), 1) );
}
inline
Point_2 midpoint(const Point_2& p1, const Point_2& p2) const
{
FT t1 = t(p1);
FT t2 = t(p2);
FT midt = (t1+t2)/2;
return f(midt);
}
inline
Point_2 f(FT t) const
{
if ( CGAL::is_negative(t) ) return rchain(-t);
return lchain(t);
}
inline
FT t(const Point_2 &p) const
{
FT tt = distance(f1, p) - distance(f1, o);
if ( right(p) ) return -tt;
return tt;
}
public:
Hyperbola_2() { STEP = FT(2); }
Hyperbola_2(const Site_2 &ff1, const Site_2 &ff2)
{
STEP = FT(2);
this->r = ff1.weight() - ff2.weight();
this->f1 = ff1.point();
this->f2 = ff2.point();
compute_origin();
}
Oriented_side
side_of_hyperbola(const Point_2 &p) const
{
double dist = distance(p, f1) - distance(p, f2) - r;
if ( dist < 0 ) return ON_NEGATIVE_SIDE;
if ( dist > 0 ) return ON_POSITIVE_SIDE;
return ON_ORIENTED_BOUNDARY;
}
template<class QTWIDGET>
void generate_points_qt(const QTWIDGET& W,
std::vector<Point_2>& pleft,
std::vector<Point_2>& pright) const
{
std::vector< Point_2 > p;
pleft.push_back(o);
pright.push_back(o);
double width = W.x_max() - W.x_min();
double height = W.y_max() - W.y_min();
FT STEP;
if ( width < height ) {
STEP = width / 500.0;
} else {
STEP = height / 500.0;
}
// double mind = distance(o, f1) - r1;
for (int i = 1; i <= 100; i++) {
p = compute_points(FT(i * i) * STEP);
if ( p.size() > 0 ) {
if ( right(p[0]) ) {
pright.push_back(p[0]);
pleft.push_back(p[1]);
} else {
pright.push_back(p[1]);
pleft.push_back(p[0]);
}
}
}
}
template<class QTWIDGET>
void draw_qt(QTWIDGET& W) const
{
std::vector< Point_2 > pleft, pright;
generate_points_qt(pleft, pright);
for (unsigned int i = 0; i < pleft.size() - 1; i++) {
W << Segment_2(pleft[i], pleft[i+1]);
}
for (unsigned int i = 0; i < pright.size() - 1; i++) {
W << Segment_2(pright[i], pright[i+1]);
}
}
void generate_points(std::vector<Point_2>& pleft,
std::vector<Point_2>& pright) const
{
std::vector< Point_2 > p;
pleft.push_back(o);
pright.push_back(o);
// double mind = distance(o, f1) - r1;
for (int i = 1; i <= 100; i++) {
p = compute_points(FT(i * i) * STEP);
if ( p.size() > 0 ) {
if ( right(p[0]) ) {
pright.push_back(p[0]);
pleft.push_back(p[1]);
} else {
pright.push_back(p[1]);
pleft.push_back(p[0]);
}
}
}
}
template< class Stream >
void draw(Stream &W) const
{
std::vector< Point_2 > pleft, pright;
generate_points(pleft,pright);
for (unsigned int i = 0; i < pleft.size() - 1; i++) {
W << Segment_2(pleft[i], pleft[i+1]);
}
for (unsigned int i = 0; i < pright.size() - 1; i++) {
W << Segment_2(pright[i], pright[i+1]);
}
}
};
template< class Stream, class Gt >
inline
Stream& operator<<(Stream& s, const Hyperbola_2<Gt> &H)
{
H.draw(s);
return s;
}
} //namespace CGAL
#endif // CGAL_HYPERBOLA_2_H