[Mesa-dev] [PATCH v2 8/8] i965 gen6: Implement pass-through GS for transform feedback.

[Paul Berry]

On 7 December 2011 13:32, Eric Anholt <eric at anholt.net> wrote:

> On Wed,  7 Dec 2011 11:09:16 -0800, Paul Berry <stereotype441 at gmail.com>
> wrote:
> > In Gen6, transform feedback is accomplished by having the geometry
> > shader send vertex data to the data port using "Streamed Vertex Buffer
> > Write" messages, while simultaneously passing vertices through to the
> > rest of the graphics pipeline (if rendering is enabled).
>
> > +   if (intel->gen >= 7) {
> > +      /* On Gen7 and later, we don't use GS (yet). */
> > +      key->need_gs_prog = false;
> > +   } else if (intel->gen == 6) {
> > +      /* On Gen6, GS is used for transform feedback. */
> > +      key->need_gs_prog = ctx->TransformFeedback.CurrentObject->Active;
>
> I like to see state accesses associated with a flag having a comment
> like /* _NEW_TRANSFORM_FEEDBACK */ right above them.  This means that
> when you're trying to manually check that state flags are correct, you
> can do one scan of the code looking to see if the nearest /*
> _NEW_WHATEVER */ comment is the right thing for each piece of state
> being accessed, and another pass to go find the state atom and make sure
> that every _NEW_WHATEVER comment in its update function is reflected in
> it.
>
> It's messy, but without some other free-per-draw-call way to get the
> flags next to the code, this is the only way I've found to keep some
> sanity while trying to debug statechanges.  Maybe when we build the
> valgrind tool I'll stop caring.
>

No need to explain, I'm 100% with you on this practice.  It was simple
oversight that prevented me from doing it here.  I'll fix it before pushing
the patches.


>
> I haven't reviewed the rest of these changes, but they're generally:
>
> Acked-by: Eric Anholt <eric at anholt.net>
>
>
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