245 lines
7.2 KiB
C++
245 lines
7.2 KiB
C++
/****************************************************************************
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* VCGLib o o *
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* Visual and Computer Graphics Library o o *
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* _ O _ *
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* Copyright(C) 2004 \/)\/ *
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* Visual Computing Lab /\/| *
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* ISTI - Italian National Research Council | *
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* \ *
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* All rights reserved. *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
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* for more details. *
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* *
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****************************************************************************/
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/****************************************************************************
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History
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$Log: not supported by cvs2svn $
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Revision 1.9 2006/07/06 12:40:34 ganovelli
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typdef ..ScalarType added
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Revision 1.8 2005/02/22 14:18:15 ponchio
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assert addded.
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Revision 1.7 2005/02/21 17:03:03 ponchio
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Added Tight creation.
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Revision 1.6 2004/12/01 16:06:59 ponchio
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Distance
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Revision 1.5 2004/09/29 13:55:33 ponchio
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Added Distance shpere - point.
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Revision 1.4 2004/04/02 09:49:01 ponchio
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Ehm... a couople of small errors.
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Revision 1.3 2004/04/02 09:44:13 ponchio
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Sphere ->Sphere3
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Revision 1.2 2004/03/25 17:25:46 ponchio
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#include sbagliato.
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Revision 1.1 2004/03/21 17:51:57 ponchio
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First version.
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****************************************************************************/
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#ifndef VCG_SPHERE_H
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#define VCG_SPHERE_H
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#include <assert.h>
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#include <vcg/space/point3.h>
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namespace vcg {
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/** \addtogroup space */
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/*@{*/
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/**
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Templated class for 3D sphere.
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This is the class for definition of a sphere in 3D space. It is stored just as a Point3 and a radius
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@param T (template parameter) Specifies the type of scalar used to represent coords.
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Various policy could be added to improve efficience (keeping square of radius for instance).
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*/
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template <class T> class Sphere3 {
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protected:
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Point3<T> _center;
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T _radius;
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public:
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typedef T ScalarType;
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Sphere3(): _radius(-1) {}
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Sphere3(const Point3<T> ¢er, T radius): _center(center), _radius(radius) {}
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T &Radius() { return _radius; }
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const T &Radius() const { return _radius; }
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Point3<T> &Center() { return _center; }
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const Point3<T> &Center() const { return _center; }
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bool IsEmpty() const { return _radius < 0; }
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///return true if @param p - Center() <= Radius()
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bool IsIn(const Point3<T> &p) const;
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void Add(const Point3<T> &p);
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void Add(const Sphere3 &sphere);
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void Intersect(const Sphere3 &sphere);
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int CreateFromBox(int n, const Point3<T> *points);
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//makes 36 iterations over the data... but get good results.
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int CreateTight(int n, const Point3<T> *points,
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T threshold = 1.01, T speed = 0.6);
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};
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template <class T> T Distance(const Sphere3<T> &sphere,
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const Point3<T> &point) {
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T dist = Distance(point, sphere.Center()) - sphere.Radius();
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if(dist < 0) dist = 0;
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return dist;
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}
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template <class T> T Distance(const Sphere3<T> &sphere,
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const Sphere3<T> &s) {
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T dist = Distance(s.Center(), sphere.Center())
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- sphere.Radius() - s.Radius();
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if(dist < 0) dist = 0;
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return dist;
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}
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typedef Sphere3<float> Sphere3f;
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typedef Sphere3<double> Sphere3d;
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template <class T> void Sphere3<T>::Add(const Sphere3<T> &sphere) {
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if(IsEmpty()) {
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*this = sphere;
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return;
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}
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Point3<T> dist = sphere.Center() - _center;
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float distance = dist.Norm();
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float fartest = distance + sphere.Radius();
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if(fartest <= _radius)
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return;
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if(distance == 0)
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_radius = sphere.Radius();
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else {
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_center += dist * ((fartest - _radius) / (dist.Norm() * 2));
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_radius = (_radius + fartest)/2;
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}
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}
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template <class T> void Sphere3<T>::Add(const Point3<T> &p) {
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if(IsEmpty()) {
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_center = p;
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_radius = 0;
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}
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Point3<T> dist = p - _center;
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float fartest = dist.Norm();
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if(fartest <= _radius) return;
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_center += dist * ((fartest - _radius) / (fartest*2));
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_radius = (_radius + fartest)/2;
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}
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template <class T> bool Sphere3<T>::IsIn(const Point3<T> &p) const {
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if(IsEmpty()) return false;
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Point3<T> dist = p - _center;
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return dist.SquaredNorm() <= _radius*_radius;
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}
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template <class T> void Sphere3<T>::Intersect(const Sphere3<T> &s) {
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float dist = Distance(_center, s.Center());
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float r = 0.5 * (_radius + s.Radius() - dist);
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if(r < 0) {
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_radius = -1;
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return;
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}
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_center = (s.Center()*(_radius - r) + _center*(s.Radius() - r))/dist;
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_radius = r;
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}
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template <class T> int Sphere3<T>::CreateFromBox(int n, const Point3<T> *points) {
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Point3f max(-1e100, -1e100, -1e100);
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Point3f min(1e100, 1e100, 1e100);
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for(int i = 0; i < n; i++) {
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for(int k = 0; k < 3; k++) {
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if(max[k] < points[i][k]) max[k] = points[i][k];
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if(min[k] > points[i][k]) min[k] = points[i][k];
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}
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}
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Center() = (min + max)/2;
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Radius() = (min - max).Norm()/2;
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return 0;
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}
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template <class T> int Sphere3<T>::CreateTight(int n, const Point3<T> *points,
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T threshold, T speed) {
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//This is quantized gradient descent... really ugly. But simple :P
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//TODO step should adapt to terrain...
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for(int i = 0; i < n; i++)
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Add(points[i]);
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Radius() *= 1.0001;
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Point3<T> center;
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T radius;
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//Test with 6 directions
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Point3f pert[6];
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T step = Radius()/8;
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int count = 0;
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while(1) {
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count++;
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T radius = Radius();
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pert[0] = Point3f(step, 0, 0);
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pert[1] = -pert[0];
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pert[2] = Point3f(0, step, 0);
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pert[3] = -pert[2];
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pert[4] = Point3f(0, 0, step);
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pert[5] = -pert[4];
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unsigned int best = 6;
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T best_radius = Radius()/threshold;
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for(unsigned int k = 0; k < 6; k++) {
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center = Center() + pert[k];
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radius = 0;
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for(unsigned int i = 0; i < n; i++) {
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float r = Distance(center, points[i]);
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if(r > radius)
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radius = r;
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}
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if(radius < best_radius) {
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best = k;
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best_radius = radius;
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}
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}
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if(best != 6) {
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Center() = Center() + pert[best];
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Radius() = best_radius;
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}
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step *= speed;
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if(step < Radius() * (threshold - 1))
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break;
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}
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Radius() *= 1.01;
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//Test we did it correctly.
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for(int i = 0; i < n; i++)
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assert(IsIn(points[i]));
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return count;
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}
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} //namespace
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#endif
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