/*  call-seq:
 *     volume = new_volume
 *
 *  Sets the volume level of the music.
 *  0.0 is total silence, 1.0 is maximum volume.
 */
VALUE rbgm_mixmusic_setvolume(VALUE self, VALUE volumev)
{
  double volume = NUM2DBL(volumev);
  Mix_VolumeMusic( (int)(volume * MIX_MAX_VOLUME) );
  return volumev;
}