4faeb12731
If an update (new frame) had been scheduled already before `_clutter_stage_cogl_presented` was called then that means it was scheduled for the wrong time. Because the `last_presentation_time` has changed since then. And using an `update_time` based on an outdated presentation time results in scheduling frames too early, filling the buffer queue (triple buffering or worse) and high visual latency. So if we do receive a presentation event when an update is already scheduled, remember to reschedule the update based on the newer `last_presentation_time`. This way we avoid overfilling the buffer queue and limit ourselves to double buffering for less visible lag. Closes: https://gitlab.gnome.org/GNOME/mutter/issues/334 Prerequisite: https://gitlab.gnome.org/GNOME/mutter/merge_requests/520 https://gitlab.gnome.org/GNOME/mutter/merge_requests/281
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 af 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.
The coding style used is primarily the GNU flavor of the GNOME coding
style
with some minor additions such as preferring stdint.h types over GLib
fundamental types, and a soft 80 character line limit. However, in general,
look at the file you're editing for inspiration.
Commit messages should follow the GNOME commit message guidelines. We require an URL to either an issue or a merge request in each commit.
License
Mutter is distributed under the terms of the GNU General Public License, version 2 or later. See the COPYING file for detalis.