It's the 10 bit equivalent to NV12 and uses the same layout as P016, i.e.
16 bit components with the lowest 6 bits set to 0 (padding), allowing us
to use 16 bit "subformats".
Thus adding support is quite trivial as we can reuse the NV12 shader.
The format is widely supported in decoding and display hardware (on Intel
since Kaby Lake), as well as modern codecs (AV1, VP9, HEVC) and has
visible quality advantages over NV12.
Note that the additional colors are lost if composited to a 8 bit RGB
framebuffer. Switching between direct scanout and compositing can thus
cause quality differences. This is no new phenomena, however, as the
same is the case already for e.g. GL clients using 10 bit formats -
including video players.
Also note that P012 and P016 could trivially added as well - it's not
done here as they are uncommen and thus hard to test.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3244>
These shaders can be used for similar formats with other component
sizes since the values are represented as floats. So whether the source
value was stored in 8bit, 10bit or 16bit doesn't matter - the driver
will covert it for us.
Thus use a Weston-inspired, more general naming scheme.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3244>
These snippets are retrieved anew every time a window is resized. But
callers never modify them, they're effectively read-only so cache them
at the place of creation.
This is required to convince the pipeline hash that each reuse of the
same snippet really is the same snippet and so the pipeline is unchanged.
`CoglPipelineSnippetList` only does shallow comparisons and there's no
need right now to reimplement it as a deep comparison.
This eliminates the log message:
> Over 50 separate %s have been generated which is very unusual,
> so something is probably wrong!
which isn't actually a leak but more a warning about wasting time.
Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/6958
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3224>
In future commits, we want to be able to handle more complex textures,
such as video frames which are encoded in a YUV-pixel format and have
multiple planes (which each map to a separate texture).
To accomplish this, we introduce a new object `MetaMultiTexture`: this
object can deal with more complex formats by handling multiple
`CoglTexture`s.
It supports shaders for pixel format conversion from YUV to RGBA, as
well as blending. While custom bleding is currently only required for
YUV formats, we also implement it for RGB ones. This allows us to
simplify code in other places and will be needed in the future once
we want to support blending between different color spaces.
Co-Authored-By: Robert Mader <robert.mader@collabora.com>
Co-Authored-By: Sebastian Wick <sebastian.wick@redhat.com>
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2191>
