8d179c078d
COGL_PIXEL_FORMAT_ABGR_2101010 is defined to mean the 2 A bits are placed in a 32 bit unsigned integer on the bits with highest significance, followed by B on the following 10 bits, and so on, until R on the 10 least significant bits. UNSIGNED_INT_2_10_10_10_REV_EXT is defined to represent color channels as ``` 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ------------------------------------------------------------------------------------- | a | b | g | r | ------------------------------------------------------------------------------------- ``` As can be seen, this matches COGL_PIXEL_FORMAT_ABGR_2101010, meaning that's the format we can directly read and write. In Cogl, when finding the GL formats, we get the tuple with the GL format given the format we pass, but we also get returned "required format" (CoglPixelFormat). This required format represents the format that is required when reading actual pixels from GLES. In GLES, the above mentioned format is the only one supported by the EXT_texture_type_2_10_10_10_REV extension, thus for other types, we need to do the CPU side conversion ourselves. To achieve this, correctly return COGL_PIXEL_FORMAT_ABGR_2101010 as the required format. The internal format should also be GL_RGB10_A2, not GL_RGBA. Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2461>
Mutter
Mutter is a Wayland display server and X11 window manager and compositor library.
When used as a Wayland display server, it runs on top of KMS and libinput. It implements the compositor side of the Wayland core protocol as well as various protocol extensions. It also has functionality related to running X11 applications using Xwayland.
When used on top of Xorg it acts as a X11 window manager and compositing manager.
It contains functionality related to, among other things, window management, window compositing, focus tracking, workspace management, keybindings and monitor configuration.
Internally it uses a fork of Cogl, a hardware acceleration abstraction library used to simplify usage of OpenGL pipelines, as well as a fork of Clutter, a scene graph and user interface toolkit.
Mutter is used by, for example, GNOME Shell, the GNOME core user interface, and by Gala, elementary OS's window manager. It can also be run standalone, using the command "mutter", but just running plain mutter is only intended for debugging purposes.
Contributing
To contribute, open merge requests at https://gitlab.gnome.org/GNOME/mutter.
It can be useful to look at the documentation available at the Wiki.
The API documentation is available at:
- Meta: https://gnome.pages.gitlab.gnome.org/mutter/meta/
- Clutter: https://gnome.pages.gitlab.gnome.org/mutter/clutter/
- Cally: https://gnome.pages.gitlab.gnome.org/mutter/cally/
- Cogl: https://gnome.pages.gitlab.gnome.org/mutter/cogl/
- CoglPango: https://gnome.pages.gitlab.gnome.org/mutter/cogl-pango/
Coding style and conventions
See HACKING.md.
Git messages
Commit messages should follow the GNOME commit message
guidelines. We require an URL
to either an issue or a merge request in each commit. Try to always prefix
commit subjects with a relevant topic, such as compositor: or
clutter/actor:, and it's always better to write too much in the commit
message body than too little.
Default branch
The default development branch is main. If you still have a local
checkout under the old name, use:
git checkout master
git branch -m master main
git fetch
git branch --unset-upstream
git branch -u origin/main
git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/main
License
Mutter is distributed under the terms of the GNU General Public License, version 2 or later. See the COPYING file for detalis.