[weston] gl-renderer: add support of WL_SHM_FORMAT_YUV420

[Daniel Stone]

Hi Vincent,

On 4 August 2016 at 14:35, Vincent Abriou <vincent.abriou at st.com> wrote:
> This patch allow weston to accept WL_SHM_FORMAT_YUV420 buffers.
>
> In a gstreamer pipeline, the support of the WL_SHM_FORMAT_YUV420 by
> weston avoid pixel conversion between software decoders and waylandsink.
> Indeed, software decoders output I420 (YUV420 planar) that willYou
> match with WL_SHM_FORMAT_YUV420.

Thanks for the patch. It would be nice if wl_shm used the same FourCC
codes as wl_drm though, i.e. this would be I420 rather than YUV420.

You could save yourself some pain by unconditionally initialising
hsub/vsub/offset rather than in every format code though, and also
perhaps just flatten hsub/vsub into a single field, given that I don't
expect we'd support asymmetric subsampling through SHM any time soon.

You should also trim the 'Change-Id' line from your patch, as we don't
use Gerrit upstream.

Aside from that, looks good to me.

Cheers,
Daniel