Re: [PATCH] mesa/st: Gallium quads, by spec, never change provoking vertex.

[Brian Paul <brianp@vmware.com>]

Corbin Simpson wrote:
>>From 215714d54a7f38b9add236bcc1c795e8b5d92867 Mon Sep 17 00:00:00 2001
> From: Corbin Simpson <MostAwesomeDude@gmail.com>
> Date: Wed, 10 Feb 2010 10:39:18 -0800
> Subject: [PATCH] mesa/st: Gallium quads, by spec, never change provoking vertex.
> 
> Fixes glean/clipFlat. Softpipe might be broken; I haven't figured out
> how to test it in this new API world. :T
> ---
>  src/mesa/state_tracker/st_extensions.c |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/src/mesa/state_tracker/st_extensions.c
> b/src/mesa/state_tracker/st_extensions.c
> index d5f5854..e2d871b 100644
> --- a/src/mesa/state_tracker/st_extensions.c
> +++ b/src/mesa/state_tracker/st_extensions.c
> @@ -137,6 +137,9 @@ void st_init_limits(struct st_context *st)
>     /* XXX separate query for early function return? */
>     st->ctx->Shader.EmitContReturn =
>        screen->get_param(screen, PIPE_CAP_TGSI_CONT_SUPPORTED);
> +
> +   /* Quads always follow GL provoking rules. */
> +   c->QuadsFollowProvokingVertexConvention = GL_FALSE;
>  }

This causes the glean clipFlat test to fail with softpipe.  The 
gallium softpipe driver _does_ implement the "quad follows provoking 
vertex" convention.

I don't have time right now to update the softpipe driver so this 
patch will have to wait a while.  Maybe someone else can look at it 
sooner.

-Brian

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