[coco-devel] fwd from garinh: Copter-Commander AL query

[David M. <dm-...@bo...>]

Forwarded for archiving...

----- Forwarded message from Garin Hiebert <ga...@tu...> -----

From: Garin Hiebert <ga...@tu...>
Subject: Copter-Commander AL query
To: dm-...@bo...
Date: Sat, 10 Mar 2001 22:41:39 +0000
X-Mailer: KMail [version 1.1.99]
Reply-To: ga...@tu...

David:

I took a look at Copter-Commander today, and have a few comments regarding 
your request for help on problems with the OpenAL code.

The audio seems to be running better on my machine than on some that you 
mention -- it's a 550MHz Athlon with a Geforce 2 for video and an SB Live for 
audio.  I get 10-12 fps continuously when running the game.  Running either 
esd or OpenAL audio, the game sounds pretty much the same, although it 
appears that you're playing around with the audio positioning differently 
with AL -- I didn't do enough testing to make sure on that.

When it comes to performance of the AL audio, one thing comes to mind which 
may help out.  I note that whenever any audio is played, an un-used source is 
being found, then the buffer for that effect is attached, then the source 
played.  For instance, when the machine gun on a copter is being shot, a new 
source is being used for each shot from the gun, which is requiring a lot of 
searching through the available sources, attaching of buffers, and "play" 
calls.

A couple of ways come to mind for reducing the number of AL calls.  The 
simplest -- for this game -- would be to allocate one source for each sound 
effect you might want to play.  It seems that you probably have few enough 
effects that this would work.  Then there wouldn't be any searching for 
sources or buffer attachment required when you want to play an effect.

If there aren't enough sources available or if you just want a more flexible 
audio engine, then you probably want to at least re-work the engine so that 
it will use single sources for as long as possible rather than continuously 
churning through new sources while repeating a single effect.  Along these 
lines, I'd be tempted to reserve some sources for popular effects such as the 
weapons, and then do more sophisticated management of sources for 
intermittent effects such as people yelling.

I look forward to playing this game more -- as I said earlier I really loved 
Rescue Raiders...

Garin

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