/*  call-seq:
 *     volume
 *
 *  Returns the current volume level of the music.
 *  0.0 is total silence, 1.0 is maximum volume.
 */
VALUE rbgm_mixmusic_getvolume(VALUE self)
{
  return rb_float_new( (double)(Mix_VolumeMusic(-1)) / MIX_MAX_VOLUME );
}