[Mesa-dev] [PATCH 1/2] mesa: Add gl_formats to cover all GLUser provided format/type combinations

[Marek Olšák]

On Sat, Nov 23, 2013 at 10:23 PM, Mark Mueller <markkmueller at gmail.com> wrote:
>
>
>
> On Sat, Nov 23, 2013 at 2:26 AM, Marek Olšák <maraeo at gmail.com> wrote:
>>
>> If there is actually hardware support, it's okay to add those formats.
>> See comments below.
>>
>> On Sat, Nov 23, 2013 at 3:59 AM, Mark Mueller <markkmueller at gmail.com>
>> wrote:
>> > How about let's forget the whole concept of GPU loading for a moment as
>> > that
>> > is only clouding the issue. As you said: "the mesa_* formats have one
>> > purpose: to be used as OpenGL textures...." When I read the OGL spec for
>> > glTexImage2D it lists GL_BGR as a format. Yet looking at mesa_* formats
>> > there is only one BGR format represented: MESA_FORMAT_BGR888. There are
>> > 8
>> > other valid OGL BGR textures that don't have MESA_FORMATs while all of
>> > the
>> > RGBs ones _are_ all there? ie. these are the OGL BGR formats that are
>> > missing:
>> >
>> >    MESA_FORMAT_BGR_INT8,
>> >    MESA_FORMAT_BGR_UINT8,
>> >    MESA_FORMAT_BGR_INT16,
>> >    MESA_FORMAT_BGR_UINT16,
>> >    MESA_FORMAT_BGR_FLOAT16,
>> >    MESA_FORMAT_BGR_INT32,
>> >    MESA_FORMAT_BGR_UINT32,
>> >    MESA_FORMAT_BGR_FLOAT32
>>
>> Our hardware doesn't support these formats, because they are not
>> aligned to a power-of-two number of components. If your hardware can
>> do them, it's okay to add them.
>>
>> >
>> > There are also RGB, RGBA, and BGRA formats missing. Completeness seems
>> > like
>> > justification enough for their inclusion:
>> >
>> >    /* Red Green Blue */
>> >    MESA_FORMAT_RGB233_REV,
>>
>> Same as above. Also please don't use _REV, use BGR332 instead.
>
>
> Definitely better.
>
>>
>>
>> >    MESA_FORMAT_RGB101111_REV,
>>
>> This format doesn't exist. I don't think you can specify it in glTexImage.
>
>
> The proposed new RGB ones are based on this statement in the spec:
> "GL_INVALID_OPERATION is generated if type is one of GL_UNSIGNED_BYTE_3_3_2,
> GL_UNSIGNED_BYTE_2_3_3_REV, GL_UNSIGNED_SHORT_5_6_5,
> GL_UNSIGNED_SHORT_5_6_5_REV, or GL_UNSIGNED_INT_10F_11F_11F_REV, and format
> is not GL_RGB."

Please read the spec carefully.

1) UNSIGNED_BYTE_3_3_2 is RGB332, and UNSIGNED_BYTE_2_3_3_REV is
BGR233. R has always 3 bits.

2) UNSIGNED_INT_10F_11F_11F_REV is already equivalent to
MESA_FORMAT_R11_G11_B10_FLOAT. The non-float version you want to add
doesn't exist.

>
>
>>
>>
>> >
>> >    /* Red Green Blue Alpha */
>> >    MESA_FORMAT_RGBA1010102,
>>
>> This one might be useful.
>>
>> >    MESA_FORMAT_RGBA2101010_REV,
>>
>> I don't think you can have R with 2 bits.
>>
>> >    MESA_FORMAT_RGBA5999_REV,
>>
>> This format doesn't exist either.
>>
>> >    MESA_FORMAT_RGBA4444,
>> >    MESA_FORMAT_RGBA4444_REV,
>>
>> These might be useful.
>>
>> >    MESA_FORMAT_RGBA1555_REV,
>>
>> I don't think you can have R with 1 bit.
>>
>> >
>> >    /* Blue Green Red Alpha */
>> >    MESA_FORMAT_BGRA_INT8,
>> >    MESA_FORMAT_BGRA_INT8_REV,
>> >    MESA_FORMAT_BGRA_UINT8,
>> >    MESA_FORMAT_BGRA_INT16,
>> >    MESA_FORMAT_BGRA_UINT16,
>> >    MESA_FORMAT_BGRA_FLOAT16,
>> >    MESA_FORMAT_BGRA_INT32,
>> >    MESA_FORMAT_BGRA_UINT32,
>> >    MESA_FORMAT_BGRA_FLOAT32,
>> >    MESA_FORMAT_BGRA4444,
>> >    MESA_FORMAT_BGRA4444_REV,
>> >    MESA_FORMAT_BGRA5551,
>>
>> All these look good.
>>
>> >    MESA_FORMAT_BGRA1555_REV,
>>
>> I don't think you can have B with 1 bit.
>>
>> >    MESA_FORMAT_BGRA1010102,
>>
>> This one looks good.
>>
>> >    MESA_FORMAT_BGRA2101010_REV,
>>
>> I don't think you can have B with 2 bits.
>>
>> >    MESA_FORMAT_BGRA5999_REV,
>>
>> This one doesn't exist either and cannot be specified by TexImage.
>
>
> BGRAs and RGBAs were based on this from the spec:
> "GL_INVALID_OPERATION is generated if type is one of
> GL_UNSIGNED_SHORT_4_4_4_4, GL_UNSIGNED_SHORT_4_4_4_4_REV,
> GL_UNSIGNED_SHORT_5_5_5_1, GL_UNSIGNED_SHORT_1_5_5_5_REV,
> GL_UNSIGNED_INT_8_8_8_8, GL_UNSIGNED_INT_8_8_8_8_REV,
> GL_UNSIGNED_INT_10_10_10_2, GL_UNSIGNED_INT_2_10_10_10_REV, or
> GL_UNSIGNED_INT_5_9_9_9_REV, and format is neither GL_RGBA nor GL_BGRA."

Nowhere can I see that B has 1 or 2 bits. Also the occurence of
GL_UNSIGNED_INT_5_9_9_9_REV seems to be a spec bug, because it should
be GL_RGB (the 5 bits contain a shared exponent).

Marek