libs/ardour/ardour/noise.h

   1 /*
   2     Copyright (C) 2000-2007 Paul Davis
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program 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
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #ifndef NOISE_H
  21 #define NOISE_H
  22
  23 /* Can be overrriden with any code that produces whitenoise between 0.0f and
  24  * 1.0f, eg (random() / (float)RAND_MAX) should be a good source of noise, but
  25  * its expensive */
  26 #ifndef GDITHER_NOISE
  27 #define GDITHER_NOISE gdither_noise()
  28 #endif
  29
  30 inline static float gdither_noise()
  31 {
  32     static uint32_t rnd = 23232323;
  33     rnd = (rnd * 196314165) + 907633515;
  34
  35     return rnd * 2.3283064365387e-10f;
  36 }
  37
  38 #endif