On Tue, 15 Feb 2000, Thomas Roell wrote:
> That is true. The problem that I was referring to is more
> subtile. Take ARB_multitexture for example. I can expose this
> extension always (whether there is more than one texture unit in HW or
> not). Half of the applications see the extension and think they always
> have 2 texture units. Hmmm ... broken application, ok. Now there are
> some apps which really want to use 2 texture units, and don't really
> care whether it's done in SW or not. If I now expose multi-texture
> with 2 texture units, while the HW supports only 1 in HW, then games,
> which are performance sensitive there will be unusable.
Well, that's a tough problem - but it's REALLY hard to imagine a
set of GL_RENDERER strings that would allow an application that
didn't have VERY specific code written for just your library to
figure that out. Think of the complexity of the string when
you might have things like:
Can do 8 light sources in hardware and another 4 in fast-path
software if you have the 3Dnow! instruction set and another
16 in non-optimised software except that if the lights are
all infinite sources then they can ALL be done in hardware.
The complexity of being able to describe all the myriad of possibilities
for all the OpenGL features would defeat your ability to describe
them all clearly - and in any case, it's astronomically unlikely
that any portable application would test them all and have
fallback code for all those complications.
> It would just be very nice to have some kind of hinting-scheme.
...and you can make an OpenGL extension to do just that - you
have glHint - and you can create a "GL_HINT_MULTITEXTURE_EXT"
that defaults to GL_FASTEST and can be set to GL_NICEST by
programs that need that second TMU in software.
I agree that there is a nasty question here - I just don't
think that cap bits (however cunningly disguised) are the
answer.
Steve Baker (817)619-2657 (Vox/Vox-Mail)
L3Com/Link Simulation & Training (817)619-2466 (Fax)
Work: [EMAIL PROTECTED] http://www.hti.com
Home: [EMAIL PROTECTED] http://web2.airmail.net/sjbaker1
