Dri2 buffer format

[Russell Shaw]

On 09/11/10 04:53, Jerome Glisse wrote:
> On Mon, Nov 8, 2010 at 10:52 AM, Russell Shaw<rjshaw at netspace.net.au>  wrote:
>> Hi,
>> How should the "format" of a DRI2 buffer be determined?
>>
>>
>> http://www.x.org/releases/current/doc/dri2proto/dri2proto.txt
>>
>> DRI2ATTACH_FORMAT { attachment: CARD32
>>             format:     CARD32 }
>>
>>     The DRI2ATTACH_FORMAT describes an attachment and the associated
>>     format.  'attachment' describes the attachment point for the buffer,
>>     'format' describes an opaque, device-dependent format for the buffer.
>>
>>
>
> As the spec says, it's opaque and only the driver understand it, intel,
> radeon, nouveau all use different things i think. DRI2 is meant to be
> use btw different driver of same hw which should all understand each
> others.

If it's opaque, how does one know what bytes are red/green/blue so that
you can draw a line in the right colour?