[Mesa-dev] [PATCH] gallium/docs: document automatic per-sample FS execution

[Roland Scheidegger]

Are you sure on this?
If you can do per-sample shading (there's a cap bit for it), then you're
supposed to implement set_min_samples(). The state tracker will set this
accordingly if these inputs are used then.

Though maybe it would make sense regardless...

Roland


Am 27.07.2017 um 19:54 schrieb Brian Paul:
> Both the GLSL 4.00 specs and DX10.1 specs specify that if a fragment
> shader uses the sample ID or sample position inputs, the shader is
> automatically run at per sample frequency.  Document that expectation
> for gallium fragment shaders.
> ---
>  src/gallium/docs/source/tgsi.rst | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
> index 0dd2ac0..d7817cc 100644
> --- a/src/gallium/docs/source/tgsi.rst
> +++ b/src/gallium/docs/source/tgsi.rst
> @@ -3331,6 +3331,9 @@ contains the current sample id (i.e. gl_SampleID) as an unsigned int.
>  Only the X component is used.  If per-sample shading is not enabled,
>  the result is (0, undef, undef, undef).
>  
> +Note that if the fragment shader uses this system value, the fragment
> +shader is automatically executed at per sample frequency.
> +
>  TGSI_SEMANTIC_SAMPLEPOS
>  """""""""""""""""""""""
>  
> @@ -3340,6 +3343,9 @@ in the render target (i.e.  gl_SamplePosition) when per-fragment shading
>  is in effect.  Position values are in the range [0, 1] where 0.5 is
>  the center of the fragment.
>  
> +Note that if the fragment shader uses this system value, the fragment
> +shader is automatically executed at per sample frequency.
> +
>  TGSI_SEMANTIC_SAMPLEMASK
>  """"""""""""""""""""""""
>  
>