[Mesa-dev] softpipe GL3 status

[Christoph Bumiller]

On 01/06/2012 08:26 PM, Ian Romanick wrote:
> On 01/06/2012 09:04 AM, Dave Airlie wrote:
>> Hi guys,
>>
>> Just a quick note, I've just spent a week or so trying to see where
>> gallium and softpipe were w.r.t GL3.0 support.
>>
>> I've pushed a branch to my repo called softpipe-gl3. It contains
>> patches in various state of usefulness but it brings the piglit
>> results to 220 failures in 7623 tests, which isn't bad.
>>
>> Outstanding known problems (stuff I've dug into).
>>
>> smooth interpolation is broken in softpipe, worth about 70-100 fixes
>> at a quick guess.
>>
>> integer abs - we have no TGSI representation for this, should we lower
>> it to something?
> 
> Or just generate some TGSI instructions to implement it.  You should be
> able to fake it with a CMP-like instruction.  I think that's how i915
> does it in hardware.
> 

Please let's just add TGSI_OPCODE_IABS, I don't want to add yet another
special-case optimization ...


>> integer SSG (set sign) - no TGSI for this, lower it?
> 
> Where is SSG being generated?  I thought ir_to_mesa was the only thing
> that generated it, and Gallium shouldn't hit that path.
> 
>> roundEven - need to implement softpipe round to match hw rounds which
>> are roundEven.
>>
>> cube shadow sampling, some reason ends up getting info from the
>> fallback texture
> 
> Something in Gallium is probably deciding that GL_DEPTH_COMPONENT is
> invalid for a cubemap and marking it as incomplete.
> 
>> fbo-stencil tests, st/mesa needs to implement
>> st_BlitFramebuffer(GL_STENCIL).
>>
>> minmax: need to increase texture array levels to 256 and missing
>> multisample support.
>>
>> the unknown stuff includes some GLSL compiler failures and generic GLX
>> issues.
> 
> Those are core Mesa problems.  I wouldn't stress about those.
> 
>> Oh and this is all only available when DRAW_USE_LLVM=false is set,
>> adding integer support to LLVM is a bit of a bigger task, and I'm not
>> sure I can really get into it at the moment.
>>
>> in case anyone is looking for any motivation on why I've been working
>> on this, it just seemed like it would be nice to have a reference sw
>> GL3.0 compatible renderer in Mesa 8.0.
> 
> I agree!  However, the VMware guys *really* want us to make the 8.0
> branch today to align with another distro's schedule.  I'm not sure if
> fixes for the issues above are acceptable post-branch or not.  You
> should talk with Brian and Jakob.
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