[Mesa-dev] [PATCH 05/18] glsl: Fail to link if inter-stage input/outputs are not assigned to stream 0

[Chris Forbes]

I had misread it -- yes, this looks correct.

On Thu, Jun 12, 2014 at 12:02 AM, Iago Toral <itoral at igalia.com> wrote:
> I am a bit confused here:
>
> Reading the code it looks like input_var should be NULL if there is no
> consumer stage. In that case, if this is a separable program and there
> is no consumer, then input_var must be NULL too, in which case the
> linker_error would never take place.
>
> If input_var is not NULL then there has to be a consumer stage, and in
> that case we should check that we can link both stages, right?
>
> Iago
>
> On Wed, 2014-06-11 at 20:48 +1200, Chris Forbes wrote:
>> This would appear to prohibit the use of multiple streams in separable
>> programs entirely. I don't think that's the right thing.
>>
>> On Wed, Jun 11, 2014 at 7:49 PM, Iago Toral Quiroga <itoral at igalia.com> wrote:
>> > Outputs that are linked to inputs in the next stage must be output to stream 0,
>> > otherwise we should fail to link.
>> > ---
>> >  src/glsl/link_varyings.cpp | 7 +++++++
>> >  1 file changed, 7 insertions(+)
>> >
>> > diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
>> > index 9883c0b..0066b4e 100644
>> > --- a/src/glsl/link_varyings.cpp
>> > +++ b/src/glsl/link_varyings.cpp
>> > @@ -1343,6 +1343,13 @@ assign_varying_locations(struct gl_context *ctx,
>> >            * consumer stage, add the output.
>> >            */
>> >           if (input_var || (prog->SeparateShader && consumer == NULL)) {
>> > +            /* Only stream 0 outputs can be consumed in the next stage */
>> > +            if (input_var && output_var->data.streamId != 0) {
>> > +               linker_error(prog, "output %s is assigned to stream=%d but "
>> > +                            "is linked to an input, which requires stream=0",
>> > +                            output_var->name, output_var->data.streamId);
>> > +               return false;
>> > +            }
>> >              matches.record(output_var, input_var);
>> >           }
>> >        }
>> > --
>> > 1.9.1
>> >
>> > _______________________________________________
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>> > mesa-dev at lists.freedesktop.org
>> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>>
>
>