Re: [tuxracer-devel] glTron music

[Jasmin P. <jf...@mu...>]

On Wed, 29 Mar 2000, Steve Baker wrote:

> Jasmin Patry wrote:
> > 
> > One disadvantage of SDL is that it's not as portable as PLIB (Linux is
> > the only fully supported UNIX-type platform).  I'll look into
> > integrating the libmikmod code (loaders/players) into SL, if it's
> > something you'd like to see added to PLIB.
> 
> I believe that someone looked at that once before.  I don't think
> it's impossible - but it may not be that easy either.
> 
> SL works with a central mixer that asks the various music sources:
> 
>   "Please make me X milliseconds of audio right now"
> 
> ...hence the sources have to be able to make a particular amount
> of sound on-demand.  Since MikMod doesn't let you tell it how
> much to generate, that's not likely to work.

Actually, it does let you tell it how much sound to generate, and that's
what SDL_mixer does.  SDL_mixer doesn't use any of libmikmod's supplied
drivers or mixers (it sets up its own libmikmod driver using mikmod's
"virtual channel mixer interface"), and calls mikmod's 
VC_WriteBytes( buffer, len ) to fill the audio buffer.  It looks fairly
straightforward.

> Hence we could call MikMod to create however much it feels like
> - store it in a buffer and just hand 'X' bytes over to SL - keeping
> what's left for next time.  Not very elegant - but it ought to be
> do-able.

No, not elegant at all, and that's not what I had in mind.

> Personally, I hate to add dependancies on yet more libraries
> since that adds so much to support hassles down the line.
> So, given the choice, I'd prefer to add whatever new music
> formats to the existing MOD player in SL rather than constructing
> some elaborate kludge to get MikMod's player to drive SL's mixer.

I wouldn't consider this an eleborate kludge.  It would use an exposed
aspect of libmikmod, without relying on libmikmod's drivers or mixers.
It needn't add dependencies to PLIB either, if you include a
stripped-down version of libmikmod in PLIB (e.g., the drivers could be
left out).  SDL_mixer does this too.

> I'm biassed though...and right now, I don't have time to do
> either modification.

Understood (I wasn't asking you to do it, I was offering to look into it
and do it myself).

Cheers,
Jasmin

-- 
Jasmin Patry               Master's Student, Dept. of Computer Science
jf...@cg...         http://www.cgl.uwaterloo.ca/~jfpatry/