Re: GL extensions

[Steve Baker <sjbaker1@airmail.net>]

Erik wrote:
> 
> I was talking to some guys a while back about a game they were working on, and
> one of them said that they won't do a linux port because linux has bad opengl
> support. After some questions, I found out that he meant it didn't have certain
> extensions that he likes (mostly concerning multi-texturing, I think).

Well, the latest Mesa does have multitexturing - and *some* Windoze
OpenGL's
don't - so if he's relying on Multitexture for his game, he's going to
be
in trouble anyway.  Most games use fallback approaches in the absence of
the extensions they'd like to have (in the case of Multitexture, that
means
re-rendering the scene for each texture).

Things are moving VERY fast in Mesa - and if you were talking to these
guys even just a few months ago, things have changed dramatically in
that
time.

It's not even that Mesa is out of date - it certainly isn't - Mesa
implements the OpenGL 1.2 API - and NONE of the OpenGL ports for
Windoze is past OpenGL 1.1.

Speaking as someone who writes OpenGL code that has to port in the
opposite direction, the lack of an OpenGL 1.2 for Windoze is a major
pain.

> Is this stopping gamehouse developers from working on linux ports?

If it is, it's not the main reason.

The main reason is just that it's a small market and those big companies
often just don't care.  Think how few games get ported to the Mac - and
their user base is still larger than Linux.  You can tell that this is
the case by how willing some companies are to have Loki do the port (and
presumably carry the risk) instead of doing it themselves.

> How is linux with extensions?

There are some. The ones that get implemented first are the ones that
the latest incarnation of Quake needs (of course).

> I haven't even looked at them... is that something we'll have to
> wait for drivers to mature before it gets tackled?

It's certainly a situation that will improve over time.

One thing I'd say to any serious games house who needs this stuff:

   "Use the Source Luke"
 
These companies have the budget to contribute to the Linux community
(as Loki does for example) - and it wouldn't hurt them to write the
extension code they need and contribute it to Mesa.

Failing that, TALK to the Mesa developers.  I'm sure that if a games
company said  "We would port <name of game(s)> to Linux if only Mesa had
<name of OpenGL extension(s)> for <name of 3D card(s)>"...then assuming
this is a game that anyone wants and that the 3D hardware can support
it, I think the needed extension would materialise from the contributors
within a reasonable amount of time.

I subscribe to the Mesa developers list - and I don't see such requests.

--
Steve Baker                (817)619-2657 (Vox/Vox-Mail)
Raytheon Systems Inc.      (817)619-2466 (Fax)
Work: sjbaker@hti.com      http://www.hti.com
Home: sjbaker1@airmail.net http://web2.airmail.net/sjbaker1