source/angleselect.cc

   1 /* This file is part of Shapes.
   2  *
   3  * Shapes is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, either version 3 of the License, or
   6  * any later version.
   7  *
   8  * Shapes is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with Shapes.  If not, see <http://www.gnu.org/licenses/>.
  15  *
  16  * Copyright 2008 Henrik Tidefelt
  17  */
  18
  19 #include <cmath>
  20
  21 #include "angleselect.h"
  22
  23 double
  24 angleSelectNorm2( double a1, double a2, double w1, double w2 )
  25 {
  26         a1 = fmod( a1, 2 * M_PI );
  27         if( a1 < 0 )
  28                 {
  29                         a1 += 2 * M_PI;
  30                 }
  31         a2 = fmod( a2, 2 * M_PI );
  32         while( a2 < a1 - M_PI )
  33                 {
  34                         a2 += 2 * M_PI;
  35                 }
  36         while( a2 > a1 + M_PI )
  37                 {
  38                         a2 -= 2 * M_PI;
  39                 }
  40         return ( w2 * a1 + w1 * a2 ) / ( w1 + w2 );
  41 }
  42