Remove all the roadblocks we've put up to keep implicit modifiers
out. Our importing code already handles them as a signal that says
'No modifiers, please!'. Now we just hope for the best and pass
things along.
This is necessary since some drivers won't produce any explicit
modifiers.
We were confusingly printing "supported format" for dmabuf formats
that we end up not adding to our list of supported formats. Don't
do that, it is confusing. At the same time, we shuold print out
the linear formats we support via mmap.
Add an implementation of GdkDmabufDownloader that uses
gsk_renderer_render_texture + GL texture download.
Since gsk isn't threadsafe, we do the download in the main thread,
taking care to not disturb the current GL context of whatever is
going on there at the time.
And since gsk renderers are expensive to create, we cache it
in the display.
Note that gsk does not yet have any special support for
dmabuf textures, so for now, they will always get downloaded
and then reuploaded as GL textures.
Trying to use it is a programming error, applications should have code
that uses real modifiers.
Also add a check to the formatsbuilder so our code doesn't include the
invalid modifier by accident.
We don't really know how to deal with it, so better force applications
to figure out what to do.
When adding the formats of a downloader, allow them to return FALSE to
mean "This method is not supported", which is a useful way to opt out
when checking GL or Vulkan extensions and finding out that the desired
one isn't supported.
This seems to be what everyone does, so we should do it, too.
Previously it was assumed that an fd of -1 would mean reusing the
previous fd with a different offset, but that seems to be uncommon.
We did have 4 ordering variations of ARGB straight,
but only 3 premultiplied. Add the missing one.
Update all the places where we switch over memory formats.
1. Split out the download function from the mmap'ing of the plane(s)
2. Make the code mmap() all the planes
3. Determine size using lseek() as documented by libdrm, instead of
trying to guess it from the format.
4. Fix some bugs, like switcheroos of width and height
Tries to sanitize the dmabuf to conform to the values expected
by Vulkan/EGL which should also be the values expected by
Wayland compositors
We put these sanitized values into the GdkDmabufTexture, by
sanitizing the input from GdkDmabufTextureBuilder, which are
controlled by the callers.
Things we do here:
1. Disallow any dmabuf format that we do not know.
1. Treat the INVALID modifier the same as LINEAR.
2. Ignore all other modifiers.
3. Try and fix various inconsistencies between V4L and Mesa,
like NV12.
*** WARNING ***
This function is not absolutely perfect, you do not have a
perfect dmabuf afterwards.
In particular, it doesn't check sizes.
Vertex arrays are available in GL and in GLES >= 3.
We don't check for the GLES extension that provided
vertex arrays in older GLES, since that requires
using different API.
This api avoids version checks all over the place.
