libs/gfx/GP_AngleUtils.c

   1 /*****************************************************************************
   2  * This file is part of gfxprim library.                                     *
   3  *                                                                           *
   4  * Gfxprim is free software; you can redistribute it and/or                  *
   5  * modify it under the terms of the GNU Lesser General Public                *
   6  * License as published by the Free Software Foundation; either              *
   7  * version 2.1 of the License, or (at your option) any later version.        *
   8  *                                                                           *
   9  * Gfxprim is distributed in the hope that it will be useful,                *
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of            *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU         *
  12  * Lesser General Public License for more details.                           *
  13  *                                                                           *
  14  * You should have received a copy of the GNU Lesser General Public          *
  15  * License along with gfxprim; if not, write to the Free Software            *
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,                        *
  17  * Boston, MA  02110-1301  USA                                               *
  18  *                                                                           *
  19  * Copyright (C) 2011      Tomas Gavenciak <gavento@ucw.cz>                  *
  20  * Copyright (C) 2012      Cyril Hrubis <metan@ucw.cz>                       *
  21  * Copyright (C) 2012      Jiri Dluhos <jiri.bluebear.dluhos@gmail.com>      *
  22  *                                                                           *
  23  *****************************************************************************/
  24
  25 #include "GP_AngleUtils.h"
  26
  27 #include <math.h>
  28
  29 double GP_NormalizeAngle(double phi)
  30 {
  31         // clamp angle to <-2*pi, 2*pi>
  32         double phi2 = fmod(phi, 2*M_PI);
  33
  34         // clamp angle to <0, 2*pi>
  35         if (phi2 < 0)
  36                 phi2 += 2*M_PI;
  37
  38         return phi2;
  39 }
  40
  41 int GP_AngleInRange(double angle, double start, double end)
  42 {
  43         if (start < end) {
  44                 return (angle >= start && angle <= end);
  45         } else {
  46                 return (angle >= start && angle <= 2*M_PI)
  47                         || (angle >= 0 && angle <= end);
  48         }
  49 }