UNDEFINED when used as source layout means that the contents of
the underlying memory becomes undefined. This isn't what we want
here: we don't want to mutate the imported pixel data.
The Vulkan spec isn't really clear what the proper value should be
here, but after discussing with driver developers [1] it seems like
UNDEFINED isn't the right one. The recommendation is to use GENERAL
instead.
[1]: https://github.com/ValveSoftware/gamescope/issues/356
(cherry picked from commit 2c4d3ad12d)
Pre-multipled sRGB values need to be un-multiplied before conversion
to linear and then re-multiplied after. Compare shaders/texture.frag.
This fixes an issue in labwc where titlebar corners (rendered as
ARGB textures) did not match the rest of the titlebar (rendered as
a solid wlr_scene_rect).
If the compositor were to try to handle a GPU reset within the lost
signal (by recreating the renderer) we should avoid referencing renderer
resources after the lost signal. This prevents use after free for such
compositors.
