[Mesa-dev] [PATCH v3 1/2] etnaviv: fix varying interpolation

[Lucas Stach]

Am Donnerstag, den 28.09.2017, 13:47 +0200 schrieb Lucas Stach:
> Hi Wladimir,
> 
> Am Dienstag, den 26.09.2017, 16:20 +0200 schrieb Wladimir J. van der
> Laan:
> > Hello Lucas,
> > 
> > On Fri, Sep 22, 2017 at 11:27:36AM +0200, Lucas Stach wrote:
> > > It seems that newer cores don't use the PA_ATTRIBUTES to decide if
> > > the
> > > varying should bypass the flat shading, but derive this from the
> > > component
> > > use. This fixes flat shading on GC880+.
> > > 
> > > VARYING_COMPONENT_USE_POINTCOORD is a bit of a misnomer now, as it
> > > isn't
> > > only used for pointcoords, but missing a better name I left it as-
> > > is.
> > 
> > I was just looking at recent command streams, and it appears that the
> > blob
> > uses VARYING_COMPONENT_USE_UNUSED even for active components.
> > I've not seen it use VARYING_COMPONENT_USE_USED at all anymore.
> > 
> > Maybe that works instead of using the POINTCOORD for this? I'm glad
> > this solved the issue, and I'm ok with merging this as-is, but I have
> > never
> > seen the blob use POINTCOORD for non-pointcoords and feel it would
> > potentially
> > interfere with point sprites in some cases.
> 
> Thanks for the info. Flat-shading isn't critical anywhere and more of a
> nice-to-have, so I guess I'm just deferring this patch until I have a
> chance to see if I can make it work in line with your observations.

Okay, I've not been able to make this work any other way yet and I
don't have any time to spend on this anymore. As this, together with
the provoking vertex thing, fixes a truckload of piglit failures I'm
going to push this anyways.

I guess we can always revisit this if it turns out to cause issues
anywhere.

Regards,
Lucas