format: add compressed formats directly by testing extensions
If a layout is usef for more texture formats than are defined in
just one extension, then this could lead to enabling compressed
formats that are actually not supported.
Do some cleanups too:
* Add the readback flag when on OpenGL because we have
glGetCompressedTexImage,
* remove special handling for VIRGL_FORMAT_ETC1_RGB8 because it
is actually not listed in the format tables,
* don't advertice ETC2 formats on OpenGL, because here
CopyImageSubData doesn't support copying these formats, so
let the guest handle these formats with the software fallback.
Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/1008>
3 files changed
