audio_group_set_gain(groupID, volume, time);
|groupID||The index of the audio group to stop (as defined in the Global Game Settings Audio Groups Tab)|
|volume||The final value for the group volume.|
|time||The length of the change in gain in milliseconds.|
With this function you can fade a group of sounds in or out over
a given length of time, or it can be used to set the group gain
instantly. The time is measured in milliseconds, and the function
requires that you input a final level of gain for the group to have
reached by the end of that time. This gain can be between 0
(silent) and 1 (full volume) and the scale is linear, such that a
value of 0.5 would be half volume. To instantly change the gain,
simply set the time argument to 0.
audio_group_set_gain(audiogroup1, 0, 5000);
The above code checks for the "space" key and then fades all the audio for "audiogroup1" down to 0 over 5 seconds.