With the new compositing scheduling, we want the screen to be redrawn as
close as possible to the next vblank. Furthermore, compositing is no
longer driven by a timer. This change removes the NoSwapEncourage swap
strategy as it doesn't make sense now, in addition to that it just does
not work on Wayland.
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.
EGL for X and EGL for Wayland backends are quite different. The main
motivation behind this change is to prepare the EGL backends for
monitoring vblank events. Things work quite differently depending on
if the EGL backend renders onto a toplevel window or overlay window.
The compositing timing algorithm assumes that glXSwapBuffers() and
eglSwapBuffers() block. While this was true long time ago with NVIDIA
drivers, nowadays, it's not the case. The NVIDIA driver queues
several buffers in advance and if the application runs out of them,
it will block. With Mesa driver, swapping buffer was never blocking.
This change makes the render backends swap buffers right after ending
a compositing cycle. This may potentially block, but it shouldn't be
an issue with modern drivers. In case it gets proven, we can move
glXSwapBuffers() and eglSwapBuffers() in a separate thread.
Note that this change breaks the compositing timing algorithm, but
it's already sort of broken with Mesa drivers.
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.
In order to allow per screen rendering, we need the Compositor to be
able to drive rendering on each screen. Currently, it's not possible
because Scene::paint() paints all screen.
With this change, the Compositor will be able to ask the Scene to paint
only a screen with the specific id.
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:
Compositing in X11 was done time shifted, meaning that we paint first, then
wait one vblank interval length and present on prepareRenderingFrame the
previous paint result. This is supposed to make sure we don't miss the vblank
and in case of block till retrace be able to continue issuing commands and
only shortly before next vblank present.
This is counter-intuitiv, not how we do it on Wayland or even on MESA with X.
The reason seems to be that the GLX backend was in the beginning written
against Nvidia proprietary driver which needed this but nowadays even this
driver defaults to non-blocking behavior on buffer swap.
Therefore remove this legacy anomaly fully and directly present after paint.
We then wait one refresh cycle and in the future can optimize this by delaying
the paint and present till shortly before vsync.
Test Plan: kwin_x11 tested on i915 and Nvidia proprietary driver.
Reviewers: #kwin
Subscribers: zzag, alexeymin, kwin
Tags: #kwin
Maniphest Tasks: T11071
Differential Revision: https://phabricator.kde.org/D23514
Summary:
Selecting not to vsync does not make sense for an X11 compositor. In the end
we want clients to be able to present async if they want to but the compositor
is supposed to send swaps with vsync to the XServer in order to not generate
tearing artifacts.
There was also a detection logic which did some questionable things in case
vsync was not available. I don't think this is necessary at all since we can
just always run a timer to present with or without vsync.
Test Plan: kwin_x11 tested on i915.
Reviewers: #kwin, zzag
Subscribers: zzag, kwin
Tags: #kwin
Maniphest Tasks: T11071
Differential Revision: https://phabricator.kde.org/D23511
Summary:
It is not clear what the advantage of triple buffering is for KWin. An X11
compositor is meant to swap buffers once every monitor cycle. For that triple
buffering is not necessary.
The functionality is not maintained, does not reliably work as displayed by
the existence of an environment variable to force some behavior, pollutes
our code and every compositing-related problem that might be mitigated with
triple buffering should find a simpler and more fitting solution with other
means.
There is one caveat which is if we shall block for retrace. We set it
currently according to the result of the swap profiler and in the most common
case with double buffering it is set to true. But on Nvidia systems this might
be actual the wrong behavior. Instead of trying to work around this ignore
the issue for now and move the overall architecture to something less complex
by presenting after paint how we do it in the Wayland DRM backend and with
double buffering on GLX (although this is at the moment also borken because
we actually present then twice).
Test Plan: kwin_x11 tested on i915.
Reviewers: #kwin, zzag
Reviewed By: #kwin, zzag
Subscribers: zzag, fredrik, kwin
Tags: #kwin
Maniphest Tasks: T11071
Differential Revision: https://phabricator.kde.org/D23504
We have lots of inconsistency at the moment in CMakeLists.txt files. Most
of it is due to kwin being a very old project. This change hopefully fixes
all of it.
Summary:
This patch is a first take at splitting up of the Compositor class into
Wayland and X11 child classes.
In this first patch we mostly deal with setup and teardown procedures.
A future goal is to further differentiate the compositing part itself too.
Test Plan: Manually X from VT and Wayland nested. Autotests pass.
Reviewers: #kwin
Subscribers: sbergeron, anthonyfieroni, zzag, kwin
Tags: #kwin
Maniphest Tasks: T11071
Differential Revision: https://phabricator.kde.org/D22195
Summary:
So far we were following a bit unique and rare doxygen comment style:
/**
* Contents of the comment.
**/
Doxygen comments with this style look balanced and neat, but many people
that contribute to KWin don't follow this style. Instead, they prefer
more traditional doxygen comment style, i.e.
/**
* Contents of the comment.
*/
Reviewing such changes has been a bit frustrating for me (so selfish!)
and for other contributors.
This change switches doxygen comment style in KWin to a more traditional
style. The main reason for doing this is to make code review process easier
for new contributors as well us.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D22812
Summary:
Currently code base of kwin can be viewed as two pieces. One is very
ancient, and the other one is more modern, which uses new C++ features.
The main problem with the ancient code is that it was written before
C++11 era. So, no override or final keywords, lambdas, etc.
Quite recently, KDE compiler settings were changed to show a warning if
a virtual method has missing override keyword. As you might have already
guessed, this fired back at us because of that ancient code. We had
about 500 new compiler warnings.
A "solution" was proposed to that problem - disable -Wno-suggest-override
and the other similar warning for clang. It's hard to call a solution
because those warnings are disabled not only for the old code, but also
for new. This is not what we want!
The main argument for not actually fixing the problem was that git
history will be screwed as well because of human factor. While good git
history is a very important thing, we should not go crazy about it and
block every change that somehow alters git history. git blame allows to
specify starting revision for a reason.
The other argument (human factor) can be easily solved by using tools
such as clang-tidy. clang-tidy is a clang-based linter for C++. It can
be used for various things, e.g. fixing coding style(e.g. add missing
braces to if statements, readability-braces-around-statements check),
or in our case add missing override keywords.
Test Plan: Compiles.
Reviewers: #kwin, davidedmundson
Reviewed By: #kwin, davidedmundson
Subscribers: davidedmundson, apol, romangg, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D22371
Summary:
QRegion::rects was deprecated in Qt 5.11. It is advised to use begin()
and end() methods instead.
Reviewers: #kwin, romangg
Reviewed By: #kwin, romangg
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D22353
Summary:
This change inits XInput extension, listens for touch events and
forwards them to our platform API. Thus touch events are forwarded on a
nested wayland session on X11.
Please note that I only tested this change on Xwayland.
Test Plan: Run nested kwin_wayland with two outputs and looked into debug console
Reviewers: #kwin
Subscribers: kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D17369
Summary:
Unfortunately a rather large change which required more refactoring than
initially expected. The main problem was that some parts needed to go
into platformsupport so that the platform plugins can link them. Due to
the rather monolithic nature of scene_opengl.h a few changes were
required:
* SceneOpenGL::Texture -> SceneOpenGLTexture
* SceneOpenGL::TexturePrivate -> SceneOpenGLTexturePrivate
* texture based code into dedicated files
* SwapProfiler code into dedicated files
* SwapProfiler only used in x11 variants
* Safety checks for OpenGL scene moved into the new plugin
* signal declared in SceneOpenGL moved to Scene, so that we don't need
to include SceneOpenGL in composite
Test Plan: Nested OpenGL compositor works
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7740
Summary:
The overlay window is only needed for the X11 based compositors. Given
that it is better suited in the X11 platform. Unfortunately it is not
possible to completely move it into the platform plugin as it is still
referenced in KWin core (e.g. SceneXRender). Due to that the
OverlayWindow in KWin core is turned into a pure virtual class with the
implementation being moved into the plugin.
The platform API gains a new virtual factory method which is only
implemented in the X11 platform.
Test Plan: Compiles
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D7193
Summary:
Instead of having the egl extensions in the global kwinglutils lib it
becomes private to the AbstractEglBackend. Just like on glx the
glxextensions are moved into the platform.
The extensions are queried from initEglAPI, that is as early as possible
after initializing the EGLDisplay. This ensures that any implementing
subclass can access the extensions early enough.
As a note: the EglOnXBackend had a potentially wrong sequence for
initializing the buffer age extension. It is now moved to the correct
place where the result is needed for the first time.
From the global API eglExtensions are removed from hasGLExtension and
the eglExtensions function is dropped. As by that initEGL did not do
anything it is also dropped.
Test Plan:
Tested nested kwin on Wayland, still works, extensions shown
in debug console
Reviewers: #kwin, #plasma
Subscribers: plasma-devel, kwin
Tags: #kwin
Differential Revision: https://phabricator.kde.org/D3396
Summary:
And finally nothing inside libkwineffects, libkwinglutils,
libkwinxrenderutils and kwineffect and kwin core uses KWin::display.
We are finally XLib free!
This change drops KWin::display and removes the include to QX11Info from
kwinglobals.h. And the libraries no longer need to link X11Extras. Due
to that removal a few seeming unrelated changes are required to add the
include where needed and linkage to X11Extras.
The biggest change is to x11 platform plugin which still needs the
display and caches it in the Platform and passes it to various places in
a way that the code doesn't need to be adjusted.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D3337
Summary:
KWin needs to support restarting the OpenGL compositor in case of a
graphics reset event.
On Wayland the tricky part is that the applications should not notice
this. Most importantly KWin cannot just destroy the EGLDisplay and create
a new one. But this is how a restart works: the complete compositor gets
torn down and recreated - including the EGLDisplay.
This change moves ownership of the EGLDisplay to the Platform.
The AbstractEglBackend subclasses query the Platform whether there is
already an EGLDisplay. Only if there is no EGLDisplay the EGLDisplay is
created and only if no EGLDisplay is registered with Wayland the bind
is performed.
Another change is regarding the destruction: the AbstractEglDisplay does
no longer unbind the Wayland display and does no longer destroy the
EGLDisplay. The EGLDisplay is destroyed by the Platform - so very late
on application exit. The Wayland display is unbound when the Compositor
terminates.
Test Plan:
Limited testing with the added auto-test. This one needs to
be extended to fully verify that OpenGL applications continue to work.
But this requires build.kde.org to support OpenGL on Wayland.
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D2202
Some error conditions did not have a warning, so all we got is
"Could not initialize rendering context". Which is not helpful to
figure out what is going wrong.
Summary:
To use eglCreateImageKhr for an X11 pixmap we need an EGLDisplay created
for the same XDisplay as the X11 pixmap. This means if we created an
EGLDisplay for a GBM device, we are not allowed to load a texture from
the X11 pixmap and can result in a crash in the driver.
Similar in the nested X11 setup the EGLDisplay is created for the
rendering window, but the X11 pixmaps are from the Xwayland server KWin
started. They don't belong to the same windowing system.
This change addresses this problem by moving the loading of X11 pixmaps
from AbstractEglTexture to EglTexture of the EglOnX11Backend. Thus for
any usage on a non X11 platform we cannot hit the code path any more.
In addition the nested X11 platform can indicate that it doesn't support
it and thus also doesn't go through the code path.
Test Plan: Tested standalone and nested X11 platform
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D1857
Summary:
The EglOnXBackend is no longer needed in the core. It's only needed by
the two x11 platform plugins. To best share it, it's moved into a common
directory and compiled into a static library which in turn is linked by
the two plugins.
Reviewers: #plasma
Subscribers: plasma-devel
Projects: #plasma
Differential Revision: https://phabricator.kde.org/D1413
