Fading out sounds when using finch in iOS

Question

I am using the Finch openAL wrapper in iOS and would like to fade out my FISound's.

Suppose I have a 30 second sound, I would like to be able to fade out the sound over 5 seconds after 15 seconds for example.

I'd like to avoid dropping down to openAL for it if possible.

Answer 1

Set up an NSTimer that repeatedly decreases the sound gain until zero. Or you can do it like this:

static const float FadeStep = 0.1;
static const NSTimeInterval FadeDelay = 0.1;

@implementation FISound

- (void) fadeOut
{
    self.gain = MAX(0, self.gain - FadeStep);
    if (self.gain > 0) {
        [self performSelector:_cmd afterDelay:FadeDelay withObject:nil];
    }
}

@end

This is a quick and dirty solution, but it should work fine for a lot of cases.