[Mesa-dev] [PATCH 2/4] gallium: add new properties for clip and cull distance usage

[Marek Olšák]

On Tue, Oct 20, 2015 at 12:03 AM, Roland Scheidegger <sroland at vmware.com> wrote:
> Am 19.10.2015 um 23:44 schrieb Marek Olšák:
>> On Mon, Oct 19, 2015 at 11:31 PM, Roland Scheidegger <sroland at vmware.com> wrote:
>>> Yes, but I still don't see much change from getting this information
>>> from the property rather than how tgsi_scan does it now, which is by
>>> just using the usage mask from the output declaration. So the writes
>>> shouldn't have to be analyzed.
>>> (There's also a slight change in patch 4/4, namely these outputs
>>> absolutely must be in order (xyzw) now as usage mask is determined
>>> solely by the number of values. That might already have been the case at
>>> least for some drivers and is probably ok for other state trackers too,
>>> it wasn't in the docs however.)
>>
>> DCL OUT[1..2], ARRAY(1), CLIPDIST
>>
>> CLIPDIST became an array declaration recently, so the usage mask isn't
>> useful unless it's extended to 8 bits.
> Oh, when and how did that happen? I totally can't find such a change
> (hence my confusion). The docs don't really reflect that neither.
> But I agree if that's the case then indeed this change looks good.
> Albeit I don't think everybody could deal with clipdist being an array
> suddenly now...

There was a change required for proper indirect addressing that
changed all inputs and outputs to array declarations for all variables
that were arrays in GLSL.

If PIPE_SHADER_CAP_TGSI_ANY_INOUT_DECL_RANGE == 0, tgsi/ureg unwinds
all incoming in/out arrays into simple declarations.

So it's optional until all drivers support that cap.

Marek