[Mesa-dev] [Bug 36295] Incorrect rendering in SPECviewperf benchmark

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=36295

--- Comment #5 from Brian Paul <brian.e.paul at gmail.com> 2011-04-17 11:32:29 PDT ---
> Oh hell no.  Report this bug to spec.  Seriously.
> 
> Issues of differing names of instance ID is one thing, but giant piles of
> functionality is completely different.  This is a MAJOR bug in viewperf.  It
> needs to be reported to them, and they need to fix it.  Period.

I reported the bugs to SPEC a few weeks ago.  Their website's "contact us"
person forwarded my email which detailed the problems (and an offer to write a
patch to correct things) to a technical person (supposedly) but I haven't
received a reply yet.  I could ping them again.

If you'd take a look at Viewperf 11's checkExtensions() function you'd probably
crap your pants.  It looks like someone made a half-hearted attempt at querying
some OpenGL features then just gave up.  It's pretty bad.

A few viewperf tests use Cg-generated shaders that apparently were simply
captured on an NVIDIA host and baked into the test.  Of course, you can't
expect an arbitrary Cg-generated shader to work on a different host.  For
example, the catia test uses GL_NV_fragment_program2 in one place (an
IF/ELSE/ENDIF) and GL_NV_vertex_program3 in a few others (but the shaders only
have some "label:" lines with no actual branches to them).  Then, there's some
use of GL_NV_primitive_restart which is predicated on whether
glXGetProcAddress() returns non-null.  Ugh.

As Jose mentioned, we have a fairly small patch that lets the ARB vp/fp
compiler accept these shaders.

In general, I don't like adding work-arounds like this into Mesa any more than
anyone else.  But it's always a trade-off.  The upside of doing a "hack" is
that people can run their apps/games/benchmarks/etc and get on with things. 
The alternative is to get error reports like the above and general hear-say of
"things don't run with Mesa".  I'd bet all the commercial OpenGL vendors have
some number of hacks added just so that important applications run to satisfy
their users.

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