[Mesa-dev] confusions about new MESA_FORMAT_xxx convention

[Brian Paul]

On 03/03/2014 08:32 AM, Chia-I Wu wrote:
> Hi list,
>
>  From formats.h, we have
>
> /* Type P formats */          /* msb <------ TEXEL BITS -----------> lsb */
>                                /* ---- ---- ---- ---- ---- ---- ---- ---- */
> MESA_FORMAT_A8B8G8R8_UNORM,   /* AAAA AAAA BBBB BBBB GGGG GGGG RRRR RRRR */
>
> But in format_unpack.c, MESA_FORMAT_A8B8G8R8_UNORM is unpacked with
> unpack_RGBA8888, which has
>
> dst[i][RCOMP] = UBYTE_TO_FLOAT( (s[i] >> 24)        );
> dst[i][GCOMP] = UBYTE_TO_FLOAT( (s[i] >> 16) & 0xff );
> dst[i][BCOMP] = UBYTE_TO_FLOAT( (s[i] >>  8) & 0xff );
> dst[i][ACOMP] = UBYTE_TO_FLOAT( (s[i]      ) & 0xff );
>
> I am confused whether R should be at MSB, as the code does, or A
> should be at MSB, as the comment says.
>
> The format is mapped to PIPE_FORMAT_ABGR8888_UNORM, which suggests we
> have the right code but wrong comment.
>

I posted a patch last week which fixes the comments to make them agree 
with the code.  Still waiting for R-b.

-Brian