On Tue, Mar 16, 2010 at 7:13 PM, Roland Scheidegger <srol...@vmware.com> wrote:
> On 16.03.2010 18:52, Keith Whitwell wrote:
>> On Tue, 2010-03-16 at 08:32 -0700, Ian Romanick wrote:
>>> I'm also a bit surprised that not detecting GL_EXT_compiled_vertex_array
>>> has any impact on our Quake3 performance.  After all, our CVA
>>> implementation doesn't do anything!  Looking at the list, it seems more
>>> likely that GL_EXT_texture_env_add is the problem.  Not having that will
>>> cause Quake3 to use additional rendering passes in quite a few cases.
>> I think if CVA isn't present, it falls back to glVertex() and friends...
> Bad...
> I'm not sure though listing that extension first really solves all
> problems. There's a quite famous bug when you bring up the information
> with the extension string it'll actually segfault. I think though that
> got fixed in later versions (though I don't know how, if by just copying
> only the first n bytes of the extension string it obviously wouldn't
> solve the problem that it doesn't recognize the CVA extension...). And
> against this you can't really do anything other than app detection and
> cut the string appropriately...

As far as I know, quake 3 code was open sourced 5 years ago. Though it
sounds like we are talking about an evil proprietary game doing bad
And not only it is GPL, but there is also a reference project
maintaining that code :)

Now are we talking about q3 or ioq3 ? If it's q3, why do we care ?
If it's ioq3, let's figure out the issues and work together with ioq3
people to fix them.

The limit for GL_EXTENSION seems to be 8192, both for ioq3 and q3.
Is any driver really exceeding that ?

Here are the size I get :
GL_RENDERER: Gallium 0.4 on NV84
GL_RENDERER: Gallium 0.4 on llvmpipe
GL_RENDERER: Software Rasterizer

Seems to be far from the limit. And with all 3 drivers, cva is
detected and enabled fine :
compiled vertex arrays: enabled

Any information about the extension string segfault ? I never heard of
it before, and never saw it happening either.

Finally the only thing I can confirm is the big performance difference :
r_ext_compiled_vertex_array=1 : 50 fps
r_ext_compiled_vertex_array=0 : 10 fps

That last point sounds like something that could be reported and could
be easily fixed.
I hope we can progress on the other issues too :)


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