[Mesa-dev] softpipe GL3 status

[Brian Paul]

On 01/06/2012 12:26 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?

Let's add new opcodes for things like this.


> 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.
>
>> 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.

Hmmm, I'm not sure what would be preventing cube textures in gallium 
or the state tracker.


>> 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.

I'd like to see us cut a release ASAP.  As usual, fixes for a stable 
branch are fine, as long as they're solid.

-Brian