[Mesa-dev] [PATCH 03/12] mesa/sso: replace Shader binding point with _Shader

[Eric Anholt]

Ian Romanick <idr at freedesktop.org> writes:

> From: Gregory Hainaut <gregory.hainaut at gmail.com>
>
> To avoid NULL pointer check a default pipeline object is installed in
> _Shader when no program is current


> diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
> index d05649c..8a03afd 100644
> --- a/src/mesa/main/mtypes.h
> +++ b/src/mesa/main/mtypes.h
> @@ -2824,6 +2824,9 @@ struct gl_pipeline_shader_state
>     /** Currently bound pipeline object. See _mesa_BindProgramPipeline() */
>     struct gl_pipeline_object *Current;
>  
> +   /* Default Object to ensure that _Shader is never NULL */
> +   struct gl_pipeline_object *Default;
> +
>     /** Pipeline objects */
>     struct _mesa_HashTable *Objects;
>  };
> @@ -4131,6 +4134,18 @@ struct gl_context
>  
>     struct gl_pipeline_shader_state Pipeline; /**< GLSL pipeline shader object state */
>     struct gl_pipeline_object Shader; /**< GLSL shader object state */
> +
> +   /**
> +    * Current active shader pipeline state
> +    *
> +    * Almost all internal users want ::_Shader instead of ::Shader.  The
> +    * exceptions are bits of legacy GLSL API that do not know about separate
> +    * shader objects.
> +    *
> +    * Points to ::Shader, ::Pipeline.Current, or ::Pipeline.Default.
> +    */
> +   struct gl_pipeline_object *_Shader;
> +

Let's see if I followed:

It points to Shader when there is a GLSL shader program bound to any
stage, it points to Pipeline.Default when all stages are not bound to a
GLSL shader but no SSO pipeline is bound, and it points to
Pipeline.Current when there are no GLSL shader programs individually
bound, but there is a SSO pipeline bound.

Is that right?  If so, baking some of that into the comments here would
be really useful.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 818 bytes
Desc: not available
URL: <http://lists.freedesktop.org/archives/mesa-dev/attachments/20140305/3e48e13f/attachment.pgp>