[Mesa-dev] [PATCH 3/3] mesa/st: implement ARB_stencil_texturing

[Roland Scheidegger]

Am 03.05.2014 11:25, schrieb Ilia Mirkin:
> If StencilSampling is enabled on the texture object, pass in an
> equivalent stencil-only format.
> 
> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
> ---
> 
> This replaces my earlier series, based on a suggestion from Michel Dänzer on
> IRC. Much simpler, and enables it for pretty much all gallium drivers.
> 
>  src/mesa/state_tracker/st_atom_texture.c | 4 ++++
>  src/mesa/state_tracker/st_extensions.c   | 5 +++++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/src/mesa/state_tracker/st_atom_texture.c b/src/mesa/state_tracker/st_atom_texture.c
> index afc6d9d..928a4ff 100644
> --- a/src/mesa/state_tracker/st_atom_texture.c
> +++ b/src/mesa/state_tracker/st_atom_texture.c
> @@ -271,6 +271,10 @@ st_get_texture_sampler_view_from_stobj(struct st_context *st,
>  
>     sv = st_texture_get_sampler_view(st, stObj);
>  
> +   if (stObj->base.StencilSampling &&
> +       util_format_is_depth_and_stencil(format))
> +      format = util_format_stencil_only(format);
> +
>     /* if sampler view has changed dereference it */
>     if (*sv) {
>        if (check_sampler_swizzle(stObj, *sv) ||
> diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
> index 33cd129..12ba82d 100644
> --- a/src/mesa/state_tracker/st_extensions.c
> +++ b/src/mesa/state_tracker/st_extensions.c
> @@ -507,6 +507,11 @@ void st_init_extensions(struct st_context *st)
>  
>        { { o(OES_compressed_ETC1_RGB8_texture) },
>          { PIPE_FORMAT_ETC1_RGB8 } },
> +
> +      { { o(ARB_stencil_texturing) },
> +        { PIPE_FORMAT_X24S8_UINT,
> +          PIPE_FORMAT_S8X24_UINT },
> +        GL_TRUE }, /* at least one format must be supported */
>     };
>  
>     /* Required: vertex fetch support. */
> 

This version looks good to me. I guess you had to support stencil
texturing for all depthstencil formats the driver claims to support, but
presumably this isn't a problem for any hardware which can do it in the
first place.
(Gallium actually is a bit lenient wrt to sampling depthstencil
textures, if you pass in a depthstencil format it will assume you want
the depth part - it would be cleaner if you'd have to specify the
corresponding depth-only format in the view).

Roland