point_funcs.h

00001 // point_funcs.h (point class copied from libCoal, subsequently modified)
00002 //
00003 //  The WorldForge Project
00004 //  Copyright (C) 2000, 2001, 2002  The WorldForge Project
00005 //
00006 //  This program is free software; you can redistribute it and/or modify
00007 //  it under the terms of the GNU General Public License as published by
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00009 //  (at your option) any later version.
00010 //
00011 //  This program is distributed in the hope that it will be useful,
00012 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 //  GNU General Public License for more details.
00015 //
00016 //  You should have received a copy of the GNU General Public License
00017 //  along with this program; if not, write to the Free Software
00018 //  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00019 //
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00021 //  the Worldforge Web Site at http://www.worldforge.org.
00022 //
00023 
00024 // Author: Ron Steinke
00025 
00026 
00027 #ifndef WFMATH_POINT_FUNCS_H
00028 #define WFMATH_POINT_FUNCS_H
00029 
00030 #include <wfmath/const.h>
00031 #include <wfmath/vector.h>
00032 #include <wfmath/point.h>
00033 
00034 namespace WFMath {
00035 
00036 template<const int dim>
00037 inline Point<dim>::Point(const Point<dim>& p) : m_valid(p.m_valid)
00038 {
00039   for(int i = 0; i < dim; ++i)
00040     m_elem[i] = p.m_elem[i];
00041 }
00042 
00043 template<const int dim>
00044 inline Point<dim>& Point<dim>::setToOrigin()
00045 {
00046   for(int i = 0; i < dim; ++i)
00047     m_elem[i] = 0;
00048 
00049   m_valid = true;
00050 
00051   return *this;
00052 }
00053 
00054 template<const int dim>
00055 inline bool Point<dim>::isEqualTo(const Point<dim> &p, double epsilon) const
00056 {
00057   CoordType delta = (CoordType) _ScaleEpsilon(m_elem, p.m_elem, dim, epsilon);
00058 
00059   for(int i = 0; i < dim; ++i)
00060     if(fabs(m_elem[i] - p.m_elem[i]) > delta)
00061       return false;
00062 
00063   return true;
00064 }
00065 
00066 template<const int dim>
00067 inline Vector<dim> operator-(const Point<dim>& c1, const Point<dim>& c2)
00068 {
00069   Vector<dim> out;
00070 
00071   for(int i = 0; i < dim; ++i)
00072     out.m_elem[i] = c1.m_elem[i] - c2.m_elem[i];
00073 
00074   out.m_valid = c1.m_valid && c2.m_valid;
00075 
00076   return out;
00077 }
00078 
00079 template<const int dim>
00080 inline Point<dim> operator+(const Point<dim>& c, const Vector<dim>& v)
00081 {
00082   Point<dim> out;
00083 
00084   for(int i = 0; i < dim; ++i)
00085     out.m_elem[i] = c.m_elem[i] + v.m_elem[i];
00086 
00087   out.m_valid = c.m_valid && v.m_valid;
00088 
00089   return out;
00090 }
00091 
00092 template<const int dim>
00093 inline Point<dim> operator-(const Point<dim>& c, const Vector<dim>& v)
00094 {
00095   Point<dim> out;
00096 
00097   for(int i = 0; i < dim; ++i)
00098     out.m_elem[i] = c.m_elem[i] - v.m_elem[i];
00099 
00100   out.m_valid = c.m_valid && v.m_valid;
00101 
00102   return out;
00103 }
00104 
00105 template<const int dim>
00106 inline Point<dim> operator+(const Vector<dim>& v, const Point<dim>& c)
00107 {
00108   Point<dim> out;
00109 
00110   for(int i = 0; i < dim; ++i)
00111     out.m_elem[i] = c.m_elem[i] + v.m_elem[i];
00112 
00113   out.m_valid = c.m_valid && v.m_valid;
00114 
00115   return out;
00116 }
00117 
00118 template<const int dim>
00119 inline Point<dim>& Point<dim>::operator=(const Point<dim>& rhs)
00120 {
00121     // Compare pointer addresses
00122     if (this == &rhs)
00123         return *this;
00124 
00125     for(int i = 0; i < dim; ++i)
00126       m_elem[i] = rhs.m_elem[i];
00127 
00128     m_valid = rhs.m_valid;
00129 
00130     return *this;
00131 }
00132 
00133 template<const int dim>
00134 inline Point<dim>& operator+=(Point<dim>& p, const Vector<dim> &rhs)
00135 {
00136     for(int i = 0; i < dim; ++i)
00137       p.m_elem[i] += rhs.m_elem[i];
00138 
00139     p.m_valid = p.m_valid && rhs.m_valid;
00140 
00141     return p;
00142 }
00143 
00144 template<const int dim>
00145 inline Point<dim>& operator-=(Point<dim>& p, const Vector<dim> &rhs)
00146 {
00147     for(int i = 0; i < dim; ++i)
00148       p.m_elem[i] -= rhs.m_elem[i];
00149 
00150     p.m_valid = p.m_valid && rhs.m_valid;
00151 
00152     return p;
00153 }
00154 
00155 template<const int dim>
00156 inline CoordType SquaredDistance(const Point<dim>& p1, const Point<dim>& p2)
00157 {
00158   CoordType ans = 0;
00159 
00160   for(int i = 0; i < dim; ++i) {
00161     CoordType diff = p1.m_elem[i] - p2.m_elem[i];
00162     ans += diff * diff;
00163   }
00164 
00165   return (fabs(ans) >= _ScaleEpsilon(p1.m_elem, p2.m_elem, dim)) ? ans : 0;
00166 }
00167 
00168 #ifndef WFMATH_NO_TEMPLATES_AS_TEMPLATE_PARAMETERS
00169 template<const int dim, template<class> class container,
00170                         template<class> class container2>
00171 Point<dim> Barycenter(const container<Point<dim> >& c,
00172                       const container2<CoordType>& weights)
00173 {
00174   // FIXME become friend
00175 
00176   typename container<Point<dim> >::const_iterator c_i = c.begin(), c_end = c.end();
00177   typename container2<CoordType>::const_iterator w_i = weights.begin(),
00178                                                  w_end = weights.end();
00179 
00180   assert("nonempty list of points" && c_i != c_end);
00181   assert("nonempty list of weights" && w_i != w_end);
00182 
00183   bool valid = c_i->isValid();
00184 
00185   CoordType tot_weight = *w_i, max_weight = fabs(*w_i);
00186   Point<dim> out;
00187   for(int j = 0; j < dim; ++j)
00188     out[j] = (*c_i)[j] * *w_i;
00189 
00190   while(++c_i != c_end && ++w_i != w_end) {
00191     tot_weight += *w_i;
00192     CoordType val = fabs(*w_i);
00193     if(val > max_weight)
00194       max_weight = val;
00195     if(!c_i->isValid())
00196       valid = false;
00197     for(int j = 0; j < dim; ++j)
00198       out[j] += (*c_i)[j] * *w_i;
00199   }
00200 
00201   // Make sure the weights don't add up to zero
00202   assert("sum of weights must be nonzero" && max_weight > 0
00203          && fabs(tot_weight) > max_weight * WFMATH_EPSILON);
00204 
00205   for(int j = 0; j < dim; ++j)
00206     out[j] /= tot_weight;
00207 
00208   out.setValid(valid);
00209 
00210   return out;
00211 }
00212 
00213 template<const int dim, template<class> class container>
00214 Point<dim> Barycenter(const container<Point<dim> >& c)
00215 {
00216   // FIXME become friend
00217 
00218   typename container<Point<dim> >::const_iterator i = c.begin(), end = c.end();
00219 
00220   assert("nonempty list of points" && i != end);
00221 
00222   Point<dim> out = *i;
00223   int num_points = 1;
00224 
00225   bool valid = i->isValid();
00226 
00227   while(++i != end) {
00228     ++num_points;
00229     if(!i->isValid())
00230       valid = false;
00231     for(int j = 0; j < dim; ++j)
00232       out[j] += (*i)[j];
00233   }
00234 
00235   for(int j = 0; j < dim; ++j)
00236     out[j] /= num_points;
00237 
00238   out.setValid(valid);
00239 
00240   return out;
00241 }
00242 #endif
00243 
00244 template<const int dim>
00245 inline Point<dim> Midpoint(const Point<dim>& p1, const Point<dim>& p2, CoordType dist)
00246 {
00247   Point<dim> out;
00248   CoordType conj_dist = 1 - dist;
00249 
00250   for(int i = 0; i < dim; ++i)
00251     out.m_elem[i] = p1.m_elem[i] * conj_dist + p2.m_elem[i] * dist;
00252 
00253   out.m_valid = p1.m_valid && p2.m_valid;
00254 
00255   return out;
00256 }
00257 
00258 template<> inline Point<2>::Point(CoordType x, CoordType y) : m_valid(true)
00259 {
00260   m_elem[0] = x;
00261   m_elem[1] = y;
00262 }
00263 
00264 template<> inline Point<3>::Point(CoordType x, CoordType y, CoordType z) : m_valid(true)
00265 {
00266   m_elem[0] = x;
00267   m_elem[1] = y;
00268   m_elem[2] = z;
00269 }
00270 
00271 #ifndef WFMATH_NO_CLASS_FUNCTION_SPECIALIZATION
00272 template<> Point<2>& Point<2>::polar(CoordType r, CoordType theta);
00273 template<> void Point<2>::asPolar(CoordType& r, CoordType& theta) const;
00274 
00275 template<> Point<3>& Point<3>::polar(CoordType r, CoordType theta,
00276                                      CoordType z);
00277 template<> void Point<3>::asPolar(CoordType& r, CoordType& theta,
00278                                   CoordType& z) const;
00279 template<> Point<3>& Point<3>::spherical(CoordType r, CoordType theta,
00280                                          CoordType phi);
00281 template<> void Point<3>::asSpherical(CoordType& r, CoordType& theta,
00282                                       CoordType& phi) const;
00283 #else
00284 void _NCFS_Point2_polar(CoordType *m_elem, CoordType r, CoordType theta);
00285 void _NCFS_Point2_asPolar(CoordType *m_elem, CoordType& r, CoordType& theta);
00286 
00287 void _NCFS_Point3_polar(CoordType *m_elem, CoordType r, CoordType theta,
00288                         CoordType z);
00289 void _NCFS_Point3_asPolar(CoordType *m_elem, CoordType& r, CoordType& theta,
00290                           CoordType& z);
00291 void _NCFS_Point3_spherical(CoordType *m_elem, CoordType r, CoordType theta,
00292                             CoordType phi);
00293 void _NCFS_Point3_asSpherical(CoordType *m_elem, CoordType& r, CoordType& theta,
00294                               CoordType& phi);
00295 
00296 template<>
00297 inline Point<2>& Point<2>::polar(CoordType r, CoordType theta)
00298 {
00299   _NCFS_Point2_polar((CoordType*) m_elem, r, theta);
00300   m_valid = true;
00301   return *this;
00302 }
00303 
00304 template<>
00305 inline void Point<2>::asPolar(CoordType& r, CoordType& theta) const
00306 {
00307   _NCFS_Point2_asPolar((CoordType*) m_elem, r, theta);
00308 }
00309 
00310 template<>
00311 inline Point<3>& Point<3>::polar(CoordType r, CoordType theta, CoordType z)
00312 {
00313   _NCFS_Point3_polar((CoordType*) m_elem, r, theta, z);
00314   m_valid = true;
00315   return *this;
00316 }
00317 
00318 template<>
00319 inline void Point<3>::asPolar(CoordType& r, CoordType& theta, CoordType& z) const
00320 {
00321   _NCFS_Point3_asPolar((CoordType*) m_elem, r, theta, z);
00322 }
00323 
00324 template<>
00325 inline Point<3>& Point<3>::spherical(CoordType r, CoordType theta, CoordType phi)
00326 {
00327   _NCFS_Point3_spherical((CoordType*) m_elem, r, theta, phi);
00328   m_valid = true;
00329   return *this;
00330 }
00331 
00332 template<>
00333 inline void Point<3>::asSpherical(CoordType& r, CoordType& theta, CoordType& phi) const
00334 {
00335   _NCFS_Point3_asSpherical((CoordType*) m_elem, r, theta, phi);
00336 }
00337 #endif
00338 
00339 } // namespace WFMath
00340 
00341 #endif  // WFMATH_POINT_FUNCS_H

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