[Mesa-dev] softpipe GL3 status

[Ian Romanick]

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.

> 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.