At the moment, our frame scheduling infrastructure is still heavily
based on Xinerama-style rendering. Specifically, we assume that painting
is driven by a single timer, etc.
This change introduces a new type - RenderLoop. Its main purpose is to
drive compositing on a specific output, or in case of X11, on the
overlay window.
With RenderLoop, compositing is synchronized to vblank events. It
exposes the last and the next estimated presentation timestamp. The
expected presentation timestamp can be used by effects to ensure that
animations are synchronized with the upcoming vblank event.
On Wayland, every outputs has its own render loop. On X11, per screen
rendering is not possible, therefore the platform exposes the render
loop for the overlay window. Ideally, the Scene has to expose the
RenderLoop, but as the first step towards better compositing scheduling
it's good as is for the time being.
The RenderLoop tries to minimize the latency by delaying compositing as
close as possible to the next vblank event. One tricky thing about it is
that if compositing is too close to the next vblank event, animations
may become a little bit choppy. However, increasing the latency reduces
the choppiness.
Given that, there is no any "silver bullet" solution for the choppiness
issue, a new option has been added in the Compositing KCM to specify the
amount of latency. By default, it's "Medium," but if a user is not
satisfied with the upstream default, they can tweak it.
Currently, the OpenGLBackend and the QPainterBackend have hooks to
indicate the start and the end of compositing cycle, but in both cases,
the hooks have different names. This change fixes that inconsistency.
The main advantage of SPDX license identifiers over the traditional
license headers is that it's more difficult to overlook inappropriate
licenses for kwin, for example GPL 3. We also don't have to copy a
lot of boilerplate text.
In order to create this change, I ran licensedigger -r -c from the
toplevel source directory.
Summary:
This patch rewrites large parts of the Wayland platform plugin, in order to
facilitate the testing of multi output behavior in nested KWin sessions.
For that a new class WaylandOutput is introduced, which is based on
AbstractOutput and by that shares functionality with our virtual and DRM
platform plugins.
The EGL/GBM and QPainter backends have been remodelled after the DRM one,
sharing similiarities there as well now.
Pointer grabbing has been rewritten to support multiple outputs, now using
pointer locking instead of confining and drawing in this case onto a sub-
surface, which get dynamically recreated in between the different output
surfaces while the cursor is being moved.
Window resizing is possible if host supports xdg-shell, but currently the
mode size does not yet fill the new window size.
The number of outputs can be set by command line argument `--output-count`,
scaling is also supported by setting the argument `--scale`.
Further steps could be:
* Enabling automatic fill of resized windows via Wayland mode change
* Multiple diverging initial sizes and scale factors for mulitple outputs
**Watch it in action:** https://youtu.be/FYItn1jvkbI
Test Plan: Tested it in live session.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, zzag, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D18465
Summary:
Source code reorganization:
The base class AbstractBackend got renamed to Platform, thus the
"backends" are "platforms" now. As they are plugins they should go
together with other KWin plugins which are nowadays in the folder
plugins.
So new location is plugins/platforms/
Reviewers: #plasma, sebas
Subscribers: plasma-devel
Projects: #plasma
Differential Revision: https://phabricator.kde.org/D1353
2016-04-12 08:01:27 +02:00
Renamed from backends/wayland/scene_qpainter_wayland_backend.cpp (Browse further)
