[Mesa-dev] [PATCH 1/3] draw: cleanup the extra attribs

[Zack Rusin]

Hi, Stéphane. 

No we should not revert to the old behavior. The old behavior was incorrect. Consider this: 

-- setup state that draws a wireframe -> draw should inject frontface 
-- the driver needs to be able to find the injected wireframe output 
-- draw 
-- setup state the draws solid fill with fragment shader using primid input -> draw should inject primid but not frontface 
-- driver needs to be able to find the injected primid but not frontface info 
-- draw 

Without cleaning the attributed before the second draw the draw will keep the frontface id in the extra attribs, incorrectly pointing the driver to a non-existing crash. That's why the attribs need to be cleaned before rendering. 

i915g simply shouldn't call draw_prepare_shader_outputs because it doesn't know what to do with the injected front-face or primid anyway. That part I'd suggest you remove. It will get you back to the old behavior. 

z 

----- Original Message -----

> Hi Zack,

> This change regresses a bunch of point sprite piglit tests on i915g. Should
> we revert back to the old behaviour? As far as I can see, it was correct (it
> was keeping the attributes in case another stage is using them).

> Stéphane

> On Thu, Aug 8, 2013 at 12:46 PM, Zack Rusin < zackr at vmware.com > wrote:

> > Before inserting new front face and prim id outputs cleanup
> 
> > the old extra outputs, otherwise our cache will use previous
> 
> > output slots which will break as soon as outputs of the current
> 
> > shader don't match the last.
> 

> > Signed-off-by: Zack Rusin < zackr at vmware.com >
> 
> > ---
> 
> > src/gallium/auxiliary/draw/draw_context.c | 1 +
> 
> > 1 file changed, 1 insertion(+)
> 

> > diff --git a/src/gallium/auxiliary/draw/draw_context.c
> > b/src/gallium/auxiliary/draw/draw_context.c
> 
> > index af9caee..2dc6772 100644
> 
> > --- a/src/gallium/auxiliary/draw/draw_context.c
> 
> > +++ b/src/gallium/auxiliary/draw/draw_context.c
> 
> > @@ -555,6 +555,7 @@ draw_get_shader_info(const struct draw_context *draw)
> 
> > void
> 
> > draw_prepare_shader_outputs(struct draw_context *draw)
> 
> > {
> 
> > + draw_remove_extra_vertex_attribs(draw);
> 
> > draw_ia_prepare_outputs(draw, draw->pipeline.ia);
> 
> > draw_unfilled_prepare_outputs(draw, draw->pipeline.unfilled);
> 
> > }
> 
> > --
> 
> > 1.7.10.4
> 
> > _______________________________________________
> 
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> 
> > mesa-dev at lists.freedesktop.org
> 
> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
> 
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