[Mesa-dev] [PATCH 4/4] st/mesa: only set up sampler compare mode for depth textures

[Roland Scheidegger]

Am 13.12.2013 21:32, schrieb Brian Paul:
> The GL_ARB_shadow spec says the shadow compare mode should have no
> effect when sampling a color texture.  As it was, it was up to
> drivers to check for that (softpipe, llvmpipe, svga and probably
> the rest don't do that).  Note: it looks like DX10 allows shadow
> compare with some non-depth formats, so this case really should be
> handled in the state tracker.
> ---
>  src/mesa/state_tracker/st_atom_sampler.c |   21 ++++++++++++---------
>  1 file changed, 12 insertions(+), 9 deletions(-)
> 
> diff --git a/src/mesa/state_tracker/st_atom_sampler.c b/src/mesa/state_tracker/st_atom_sampler.c
> index 447788c..57670ce 100644
> --- a/src/mesa/state_tracker/st_atom_sampler.c
> +++ b/src/mesa/state_tracker/st_atom_sampler.c
> @@ -133,12 +133,17 @@ convert_sampler(struct st_context *st,
>     const struct gl_texture_object *texobj;
>     struct gl_context *ctx = st->ctx;
>     struct gl_sampler_object *msamp;
> +   const struct gl_texture_image *teximg;
> +   GLenum texBaseFormat;
>  
>     texobj = ctx->Texture.Unit[texUnit]._Current;
>     if (!texobj) {
>        texobj = _mesa_get_fallback_texture(ctx, TEXTURE_2D_INDEX);
>     }
>  
> +   teximg = texobj->Image[0][texobj->BaseLevel];
> +   texBaseFormat = teximg ? teximg->_BaseFormat : GL_RGBA;
> +
>     msamp = _mesa_get_samplerobj(ctx, texUnit);
>  
>     memset(sampler, 0, sizeof(*sampler));
> @@ -176,12 +181,9 @@ convert_sampler(struct st_context *st,
>         msamp->BorderColor.ui[2] ||
>         msamp->BorderColor.ui[3]) {
>        const struct st_texture_object *stobj = st_texture_object_const(texobj);
> -      const struct gl_texture_image *teximg;
>        const GLboolean is_integer = texobj->_IsIntegerFormat;
>        union pipe_color_union border_color;
>  
> -      teximg = texobj->Image[0][texobj->BaseLevel];
> -
>        if (st->apply_texture_swizzle_to_border_color && stobj->sampler_view) {
>           const unsigned char swz[4] =
>           {
> @@ -193,25 +195,26 @@ convert_sampler(struct st_context *st,
>  
>           st_translate_color(&msamp->BorderColor,
>                              &border_color,
> -                            teximg ? teximg->_BaseFormat : GL_RGBA, is_integer);
> +                            texBaseFormat, is_integer);
>  
>           util_format_apply_color_swizzle(&sampler->border_color,
>                                           &border_color, swz, is_integer);
>        } else {
>           st_translate_color(&msamp->BorderColor,
>                              &sampler->border_color,
> -                            teximg ? teximg->_BaseFormat : GL_RGBA, is_integer);
> +                            texBaseFormat, is_integer);
>        }
>     }
>  
>     sampler->max_anisotropy = (msamp->MaxAnisotropy == 1.0 ?
>                                0 : (GLuint) msamp->MaxAnisotropy);
>  
> -   /* only care about ARB_shadow, not SGI shadow */
> -   if (msamp->CompareMode == GL_COMPARE_R_TO_TEXTURE) {
> +   /* If sampling a depth texture and using shadow comparison */
> +   if ((texBaseFormat == GL_DEPTH_COMPONENT ||
> +        texBaseFormat == GL_DEPTH_STENCIL) &&
> +       msamp->CompareMode == GL_COMPARE_R_TO_TEXTURE) {
>        sampler->compare_mode = PIPE_TEX_COMPARE_R_TO_TEXTURE;
> -      sampler->compare_func
> -         = st_compare_func_to_pipe(msamp->CompareFunc);
> +      sampler->compare_func = st_compare_func_to_pipe(msamp->CompareFunc);
>     }
>  
>     sampler->seamless_cube_map =
> 

Series looks good to me. Note that d3d10 not just allows using non-depth
textures for comparison filter, but requires it (you can't sample depth
textures at all, they always use the corresponding color view - granted
the resource could be depth or not but that shouldn't matter).

Roland