Re: [Chromium-dev] Chromium and Cluster GPUs

[Brian P. <bri...@tu...>]

Chris Johnson wrote:
> Brian Paul wrote:
> 
> 
>>When cgGLIsProfileSupported() is called, I believe it calls
>>glGetString() to test if particular extensions are available.
>>The tilesort SPU should only report those GL extensions that 
>>are supported by all the rendering/server nodes.  So, Cg
>>should not be using vertex/fragment extensions that the Chromium
>>configuration can't support.
> 
> 
> Sorry I've lost the original post.  This is a followup to my problem
> with shaders running across a tile display.  My objects were not being
> colored correctly when tilesorted out to my cluster, but everything
> displayed fine when run on the application node.  Someone advised me to
> check the hardware on the cluster machines, and sure enough, our cards
> don't support vertex programs.  (And the application node does.)
> 
> However, Chromium does not appear to be checking the extensions on the
> remote machines, as described in Brian's text above.  When I run my
> application on the application node, I don't seem to get any notice of
> the cluster machine's lack of support for vertex programs.  The
> application runs, but without any color from the shader.
> 
> For experimentation sake, I moved my application over to one of the
> cluster machines and compiled and ran there.  This time the check for
> the appropriate extension failed and my application quit, as expected.

Can you try running the arbfraglight demo included with Chromium?
It uses GL_ARB_vertex_program and GL_ARB_fragment_program.  When I run 
it with tilesort with GL drivers that don't support those extensions 
the demo exits with the expected error message.

Next, can you try one of the Cg SDK demos like cg_thinfilm?  When I 
run it here (without a fragment_program-capable driver I get:

[...]
CR Debug(yutani:28436): Tilesort SPU: CreateWindow(:0.0, 0x2f)
******** Using ARBVP1 profile
Fragment programming extensions (GL_ARB_fragment_program or 
GL_NV_fragment_program) not supported, exiting...
CR Warning(yutani:28436): Cleaning up SPU tilesort
CR Debug(yutani:28436): Destroying a context (id=1 addr=0x40f5d008)
CR Warning(yutani:28436): Cleaning up SPU error


-Brian