[Mesa-dev] [PATCH 2/7] glsl: add support for ARB_blend_func_extended (v2)

[Dave Airlie]

On Mon, Apr 9, 2012 at 9:13 PM, Eric Anholt <eric at anholt.net> wrote:
> On Tue,  3 Apr 2012 14:16:52 +0100, Dave Airlie <airlied at gmail.com> wrote:
>> From: Dave Airlie <airlied at redhat.com>
>>
>> This adds index support to the GLSL compiler.
>>
>> I'm not 100% sure of my approach here, esp without how output ordering
>> happens wrt location, index pairs, in the "mark" function.
>>
>> Since current hw doesn't ever have a location > 0 with an index > 0,
>> we don't have to work out if the output ordering the hw requires is
>> location, index, location, index or location, location, index, index.
>> But we have no hw to know, so punt on it for now.
>>
>> v2: index requires layout - catch and error
>>     setup explicit index properly.
>
> I don't like this magic 4 that's unexplained.  It seems like the second
> fragment output should have a totally separate ir_variable->location
> assigned.  Whether that's in a separate space like FRAG_RESULT_DUALSRC_0
> that comes after all the FRAG_RESULT_DATAn, or whether it's just
> FRAG_RESULT_DATA1 since we're not anticipating dual source max buffers
> going beyond 1, 4 doesn't seem like the right number.

Yeah the reason I left it all configurable was I wasn't sure how
flexible we should leave the GLSL compiler.

But I personally don't see hw with index > 1 and location > 0 unless
index gets re-purposed for something else.

I'll resend a smaller patch that just puts index after location.

Dave.