[Mesa-dev] [PATCH 1/7] gallium: try to cleanup a bit of the format mess created with pipe-video merge

[Roland Scheidegger]

Am 01.09.2011 17:23, schrieb Younes Manton:
> On Thu, Sep 1, 2011 at 11:08 AM, Christoph Bumiller
> <e0425955 at student.tuwien.ac.at> wrote:
>> On 01.09.2011 17:02, Younes Manton wrote:
>>> On Thu, Sep 1, 2011 at 10:56 AM, Michel Dänzer <michel at daenzer.net> wrote:
>>>> On Don, 2011-09-01 at 15:50 +0200, Christian König wrote:
>>>>> Start with correctly defining IA44 and AI44 formats.
>>>>>
>>>>> Signed-off-by: Christian König <deathsimple at vodafone.de>
>>>>> ---
>>>>>  src/gallium/auxiliary/util/u_format.csv   |    6 +++-
>>>>>  src/gallium/auxiliary/util/u_format_yuv.c |   38 ---------------------------
>>>>>  src/gallium/auxiliary/util/u_format_yuv.h |   40 -----------------------------
>>>>>  3 files changed, 4 insertions(+), 80 deletions(-)
>>>>>
>>>>> diff --git a/src/gallium/auxiliary/util/u_format.csv b/src/gallium/auxiliary/util/u_format.csv
>>>>> index a3d2aae..b1a85a5 100644
>>>>> --- a/src/gallium/auxiliary/util/u_format.csv
>>>>> +++ b/src/gallium/auxiliary/util/u_format.csv
>>>>> @@ -265,5 +265,7 @@ PIPE_FORMAT_YV16                  , other, 1, 1, x8  , x8  , x8  , x8  , xyzw, y
>>>>>  PIPE_FORMAT_IYUV                  , other, 1, 1, x8  , x8  , x8  , x8  , xyzw, yuv
>>>>>  PIPE_FORMAT_NV12                  , other, 1, 1, x8  , x8  , x8  , x8  , xyzw, yuv
>>>>>  PIPE_FORMAT_NV21                  , other, 1, 1, x8  , x8  , x8  , x8  , xyzw, yuv
>>>>> -PIPE_FORMAT_IA44                  , other, 1, 1, x8  , x8  , x8  , x8  , xyzw, yuv
>>>>> -PIPE_FORMAT_AI44                  , other, 1, 1, x8  , x8  , x8  , x8  , xyzw, yuv
>>>>> +
>>>>> +# Indexed with Alpha
>>>>> +PIPE_FORMAT_IA44                  , plain, 1, 1, un4 , un4 ,     ,     , y00x, rgb
>>>>> +PIPE_FORMAT_AI44                  , plain, 1, 1, un4 , un4 ,     ,     , x00y, rgb
>>>> I think the 'I' stands for 'intensity', not 'indexed'? Same issue in
>>>> patch 4.
>>>>
>>>> I didn't notice any other issues in the patches.
>>> It's an index actually, 4 bits, into a 16-entry palette.
>> I'm curious, where is this palette ? I don't see it in the gallium
>> interface ...
>>
>> And if you have to explicitly look it up in the shader, then this is
>> just R4_UINT_A4_UNORM (or even just R4A4_UNORM).
>>
>> For me, "indexed" implies that the texture unit performs the lookup
>> implicitly.
> 
> The palette is currently an explicit lookup in the shader, but it
> doesn't have to be, depending on what your hardware can do (for both
> shader decoding and HW decoders). Anyway, we used to alias some of
> these video formats to existing formats where they matched, but when
> merging pipe-video to master there was concern among some that it
> wasn't the right thing to do.

I think the concern was that you have different formats using the same
identifier and just treating them differently depending on some magic
(i.e. the context they are used). So you have some RGB format and just
when it's used in some video context you suddenly decide it's actually
yuv data.
But if some formats really are the same, there's no reason to have
different identifiers.

Roland