[Openal] Transparently mixing many sounds

[Nolan Darilek]

Hi all, new here. I'm not entirely sure how to accomplish this, so  
hopefully I'll find a solution here.

I'm trying to design an object-oriented sound system between OpenAL  
and a 3-D game engine. The system should be highly transparent--users  
of the 3-D engine attach a SoundNode to game objects, set its sample  
or stream and the sound's velocity/position/orientation are updated  
accordingly. Ideally, the developer need do no more than set/change  
the sound and various high-level properties, letting the lower-level  
layer handle everything else.

And I have it mostly working. Where it fails is when I try to  
allocate more sounds than were initially requested--the game explodes  
rather messily. Ideally, this shouldn't happen.

First, does OpenAL include any elegant way of handling this? If not:

I have this idea to catch the exception when it is thrown, storing  
the number of playing sounds as the maximum that can be allocated.  
Then, whenever that maximum is reached, the system enables sounds  
based on a) whether a priority flag is set and b) their perceived  
loudness. In this way, sounds that are less perceptive are  
deactivated while the more obvious ones drown them out, so to speak.

Given a distance from the listener, gain and roll-off factor, plus  
perhaps the reference distance and other variables which I may not  
yet be considering, is there some way to calculate the sound's  
perceived volume? It need not be in any actual units--I simply need  
to determine how loud the source is when compared with others. It  
also need not be exact--just some reasonable approximation would be  
great.

Thanks.