[Mesa-dev] [PATCH] glsl: Raise a link error for non-SSO ES programs with a TES but no TCS.

[Andres Gomez]

I would welcome a reference to the text in Secption 7.3 of the OpenGL
ES 3.2 specs as a code comment and commit text but, other than that,
this is:

Reviewed-by: Andres Gomez <agomez at igalia.com>

On Wed, 2017-02-22 at 17:54 -0800, Kenneth Graunke wrote:
> OpenGL allows the TCS to be missing and supplies an implicit passthrough
> shader, but OpenGL ES does not.
> 
> One open question is how to handle this for ARB_ES3_2_compatibility.
> This patch raises the link error for all ES shading language programs,
> but it might make sense to base it on the API.  The approach taken in
> this patch is more restrictive, but should still allow any valid ES
> programs to work in GL.
> 
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> ---
>  src/compiler/glsl/linker.cpp | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp
> index b6f8bc4212e..9e68c6e2d71 100644
> --- a/src/compiler/glsl/linker.cpp
> +++ b/src/compiler/glsl/linker.cpp
> @@ -4743,6 +4743,16 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
>                        "tessellation evaluation shader\n");
>           goto done;
>        }
> +
> +      if (prog->IsES) {
> +         if (num_shaders[MESA_SHADER_TESS_EVAL] > 0 &&
> +             num_shaders[MESA_SHADER_TESS_CTRL] == 0) {
> +            linker_error(prog, "GLSL ES requires non-separable programs "
> +                         "containing a tessellation evaluation shader to also "
> +                         "be linked with a tessellation control shader\n");
> +            goto done;
> +         }
> +      }
>     }
>  
>     /* Compute shaders have additional restrictions. */
-- 
Br,

Andres