The clear background is the most useful, and the old behaviour can
be achieved by filling the entire viewport with a white paint.ColorOp.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
The CPU fallback of the compute renderer needs ReadPixels data in OpenGL
format (origin at bottom left). Unfortunately, the OpenGL driver
automatically mirrors images in the Y-axis to match the top left origin
image.RGBA.
Remove the mirroring from the driver and introduce a DownloadImage to
restore the old behaviour.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
There are no longer any importers of package backend outside of
gioui.org/gpu. Move it internally, and rename it to the slightly more
specific "driver" while we're at it.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Elias Naur