Hi guys,

I am about to buy a new GPU to satisfy my programming needs, as I will 
have to implement a fair amount of custom lighting shaders among other 
things. I would ideally like to use the GLSL of OpenGL 2.0, so my 
question would be which video card/driver provides the best support for 
this? More specifically, I can get a good price for a 9800 Pro, I guess 
the hardware is powerful enough, what about the ATI drivers?

Many thanks

Alex

Alexis Gatt wrote:

> specifically, I can get a good price for a 9800 Pro, I guess
> the hardware is powerful enough,

No, not enough for OpenGL 2.x, which requires Shader Model 3 (how
it is called by DirectX). ATM _only_ nVidia GeForceFX 6600 or
better have it; ATI Radeon X800 is merely a boosted up Radeon
9800 with a few more pipelines and some conditional command. But
cool things like texture values fetch in the vertex shaders
currently will only work with nVidia.

> what about the ATI drivers? 

I'd like to cite Barny from HL1: "I've got a baaad feeling about
this". ATI drivers once were the most utter mess I've seen so
far. They did quite some work to catch up, but there are still
issues.

Wolfgang Draxinger
-- 

Wolfgang Draxinger wrote:
> Alexis Gatt wrote:
> 
> 
>>specifically, I can get a good price for a 9800 Pro, I guess
>>the hardware is powerful enough,
> 
> 
> No, not enough for OpenGL 2.x, which requires Shader Model 3 (how
> it is called by DirectX). ATM _only_ nVidia GeForceFX 6600 or
> better have it; 

6600 or 6600GT?  I was told said the 6600 doesn't have it, but the 
6600GT and above do.  Similarly for the 6800.

Alexis Gatt wrote:
> Hi guys,
> 
> I am about to buy a new GPU to satisfy my programming needs, as I will 
> have to implement a fair amount of custom lighting shaders among other 
> things. I would ideally like to use the GLSL of OpenGL 2.0, so my 
> question would be which video card/driver provides the best support for 
> this? More specifically, I can get a good price for a 9800 Pro, I guess 
> the hardware is powerful enough, what about the ATI drivers?
> 

Here's a list of cards which support it:

http://www.delphi3d.net/hardware/extsupport.php?extension=GL_ARB_shading_language_100

A 9800 can do it no problem, but I'm not sure
it's the "best".

ATI drivers are much, much better than they used
to be. Ignore anything/anybody which hasn't
been updated in the last year or so. Their tech
support is very good as well. If you find a bug
then just email them with a decent example of
the problem and they'll usually fix it by the
next release.


-- 
<\___/>
/ O O \
\_____/  FTB.    For email, remove my socks.

In science it often happens that scientists say, 'You know
that's a really good argument; my position is mistaken,'
and then they actually change their minds and you never
hear that old view from them again.  They really do it.
It doesn't happen as often as it should, because scientists
are human and change is sometimes painful.  But it happens
every day.  I cannot recall the last time something like
that happened in politics or religion.

- Carl Sagan, 1987 CSICOP keynote address

fungus wrote:
> ATI drivers are much, much better than they used
> to be. Ignore anything/anybody which hasn't
> been updated in the last year or so. Their tech
> support is very good as well. If you find a bug
> then just email them with a decent example of
> the problem and they'll usually fix it by the
> next release.

On what OS?

We just released some OpenGL-based commercial software for Linux:

  http://www.ffconsultancy.com/products/presenta/

and our beta tests showed that ATi were much more unstable than nVidia. Our
official advise is to use software rendering if you have problems with an
ATi card.

-- 
Dr Jon D Harrop, Flying Frog Consultancy
http://www.ffconsultancy.com

fungus wrote:

>
http://www.delphi3d.net/hardware/extsupport.php?extension=GL_ARB_shading_language_100
> 
> A 9800 can do it no problem, but I'm not sure
> it's the "best".

However only limited (no loops and conditional code).
 
> ATI drivers are much, much better than they used
> to be. Ignore anything/anybody which hasn't
> been updated in the last year or so.

Normally I'm updating my drivers the week they get released.

> Their tech 
> support is very good as well. If you find a bug
> then just email them with a decent example of
> the problem and they'll usually fix it by the
> next release.

The stencil buffer bug I found about 3 days after I got my Radeon
9800 in November 2003 got fixed October 2004; personally I think
that this is actually a HW bug and ATI implemented some sort of
the workaround I figured out and sent them.

Also there were some errors in the GLSL compiler, that however
got fixed within 4 months after I found them.

Wolfgang Draxinger
-- 

Wolfgang Draxinger <wdraxinger@darkstargames.de> writes:

> fungus wrote:
> 
> >
> http://www.delphi3d.net/hardware/extsupport.php?extension=GL_ARB_shading_language_100
> > 
> > A 9800 can do it no problem, but I'm not sure
> > it's the "best".
> 
> However only limited (no loops and conditional code).

I have one it works most often, the drivers have been alot better the
last years, but programming it is problematic due to "no loops and
conditional code" in hardware and a restricted number of instructions
means that the code will be unrolled and the number of instructions
will be to large and software emulated.

Stuff like noise3() can't be used, it's a pain and I'm thinking of buying
a new one, Nvidia seems to have catched up the performance.

Do the newer ATI cards have branching and loops?

/Dan