[Mesa-dev] [PATCH 1/1] Adjust MESA_FORMAT color component ordering to match API docs

[Michel Dänzer]

On Don, 2013-12-19 at 13:56 -0800, Mark Mueller wrote:
> Adjust MESA_FORMAT color component ordering to match API docs, driver
> specific formats (e.g. PIPE_FORMATs),

Actually, there are a couple of examples of other format definitions
which match the Mesa formats before your change but no longer after it,
e.g. in the DRI and i915, nouveau and radeon driver code.

Changing the Mesa format definitions will be confusing for people
switching between branches with and without your change.

Also, because these Mesa formats are defined as packed values, you're
essentially changing the notation from big endian (aka human readable)
to little endian. It's unfortunate that the packed PIPE_FORMATs are
named in little endian order, that's a concession we had to make when
adding them.

Overall, I'm afraid this change doesn't look very good at all to me. At
the very least though, you'd also have to change the order of component
sizes for formats such as MESA_FORMAT_BGRA2101010_UNORM or
MESA_FORMAT_BGRA1555_UNORM, otherwise they're just plain wrong.


> and actual use on common platforms.

What does that mean?


> Remove comments giving MESA_FORMAT color packings, some of which are
> misleading.

Which ones are misleading, and how?


> diff --git a/src/mesa/main/formats.h b/src/mesa/main/formats.h
> index 94fc7a0..f224ed5 100644
> --- a/src/mesa/main/formats.h
> +++ b/src/mesa/main/formats.h
> @@ -62,67 +62,68 @@ typedef enum
>     MESA_FORMAT_NONE = 0,
>  
>     /** 
> -    * \name Basic hardware formats
> +    * \name Basic API user space data formats

All of Mesa is in user space. :)

> +    * Please refer to API documentation for more information on format
> +    * packing
>      */

What API documentation?


-- 
Earthling Michel Dänzer            |                  http://www.amd.com
Libre software enthusiast          |                Mesa and X developer