[Mesa-dev] [PATCH] glsl: do not emit error for non written varyings on OpenGL ES

[Ian Romanick]

On 09/16/2014 04:21 AM, Tapani Pälli wrote:
> Patch fixes following test case from 'shaders-with-varyings' WebGL
> conformance suite: "vertex shader with unused varying and fragment
> shader with used varying must succeed"

Oh bother.  Using the same rationale as before, could we get a warning
from the linker?

> Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
> ---
>  src/glsl/link_varyings.cpp | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
> index 54ceae1..fb2d88c 100644
> --- a/src/glsl/link_varyings.cpp
> +++ b/src/glsl/link_varyings.cpp
> @@ -1451,7 +1451,7 @@ assign_varying_locations(struct gl_context *ctx,
>  
>           if (var && var->data.mode == ir_var_shader_in &&
>               var->data.is_unmatched_generic_inout) {
> -            if (prog->Version <= 120) {
> +            if (prog->Version <= 120 && !prog->IsES) {
>                 /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
>                  *
>                  *     Only those varying variables used (i.e. read) in
> @@ -1463,6 +1463,16 @@ assign_varying_locations(struct gl_context *ctx,
>                  * We interpret this text as meaning that the VS must
>                  * write the variable for the FS to read it.  See
>                  * "glsl1-varying read but not written" in piglit.
> +                *
> +                * Note that this is not an error on OpenGL ES:
> +                *
> +                * On Page 91 (Page 97 of the PDF) of the GLSL ES 1.0 spec:
> +                *
> +                *     If the vertex shader declares but doesn't write to a
> +                *     varying and the fragment shader declares and reads it,
> +                *     is this and error?
> +                *
> +                *     RESOLUTION: No.
>                  */
>  
>                 linker_error(prog, "%s shader varying %s not written "
>