This logs to a tracefs filesystem which can be viewed in tools such as
gpuvis to see precise timings of activities in relation to other trace
markers in X or graphic drivers.
This patch is loosely based on D23114. Though modified with thread
safety, support for string building, and a RAII pattern for durations.
Ultimately that expanded it somewhat.
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.
At the moment, the Screens class is convoluted with ifdefs because of
MockScreens.
The goal of this change is to reduce the number of usages of the
MockScreens class so it is possible to get rid of the ifdefs.
Since the Screens class is a convenience wrapper around AbstractOutput
objects that come from the Platform, it should not be platform-specific.
By dropping createScreens(), output-related code becomes simpler.
This change introduces a new component - ColorManager that is
responsible for color management stuff.
At the moment, it's very naive. It is useful only for updating gamma
ramps. But in the future, it will be extended with more CMS-related
features.
The ColorManager depends on lcms2 library. This is an optional
dependency. If lcms2 is not installed, the color manager won't be built.
This also fixes the issue where colord and nightcolor overwrite each
other's gamma ramps. With this change, the ColorManager will resolve the
conflict between two.
Effects are given the interval between two consecutive frames. The main
flaw of this approach is that if the Compositor transitions from the idle
state to "active" state, i.e. when there is something to repaint,
effects may see a very large interval between the last painted frame and
the current. In order to address this issue, the Scene invalidates the
timer that is used to measure time between consecutive frames before the
Compositor is about to become idle.
While this works perfectly fine with Xinerama-style rendering, with per
screen rendering, determining whether the compositor is about to idle is
rather a tedious task mostly because a single output can't be used for
the test.
Furthermore, since the Compositor schedules pointless repaints just to
ensure that it's idle, it might take several attempts to figure out
whether the scene timer must be invalidated if you use (true) per screen
rendering.
Ideally, all effects should use a timeline helper that is aware of the
underlying render loop and its timings. However, this option is off the
table because it will involve a lot of work to implement it.
Alternative and much simpler option is to pass the expected presentation
time to effects rather than time between consecutive frames. This means
that effects are responsible for determining how much animation timelines
have to be advanced. Typically, an effect would have to store the
presentation timestamp provided in either prePaint{Screen,Window} and
use it in the subsequent prePaint{Screen,Window} call to estimate the
amount of time passed between the next and the last frames.
Unfortunately, this is an API incompatible change. However, it shouldn't
take a lot of work to port third-party binary effects, which don't use the
AnimationEffect class, to the new API. On the bright side, we no longer
need to be concerned about the Compositor getting idle.
We do still try to determine whether the Compositor is about to idle,
primarily, because the OpenGL render backend swaps buffers on present,
but that will change with the ongoing compositing timing rework.
There were multiple other cases of placing the mouse between screens at
the start of tests. It seems to be all copy paste.
Only maximise and pointerConstraints were failing before this, but we
may as well fix all of them.
Night Color adjusts the color temperature based on the current time in
your location. It's not a generic color correction module per se.
We need a central component that can be used by both night color and
colord integration to tweak gamma ramps and which will be able to
resolve conflicts between the two. The Night Color manager cannot be
such a thing because of its very specific usecase.
This change converts Night Color into a plugin to prepare some space for
such a component.
The tricky part is that the dbus api of Night Color has "ColorCorrect"
in its name. I'm afraid we cannot do that much about it without breaking
API compatibility.
A plugin may need to access kwinApp() or kwinApp()->platform() during
tear down, but the problem is that plugins are destroyed after the
kwinApp() object. The plugin manager must be destroyed explicitly while
the application is still valid to ensure that no crash will occur
during compositor teardown.
xdgshell allows clients to specify which output should we fill on
set_fullscreen. This change takes this request into consideration
instead of ignoring it.
The scripting api is not suitable for implementing all features that
should not be implemented in libkwin. For example, the krunner
integration or screencasting are the things that don't belong to be
compiled right into kwin and yet we don't have any other choice.
This change introduces a quick and dirty plugin infrastructure that
can be used to implement things such as colord integration, krunner
integration, etc.
Without the KWindowSystem integration plugin, Wayland experience will be
negatively affected because windows created by kwin itself won't behave
as desired. Therefore it makes little sense to load this plugin at runtime.
QTRY_COMPARE doesn't work well with how we do our wayland event
dispatching.
We know the client hasn't processed any events yet, so we can safely do
a normal wait.
On wayland, we know we're always going to load our internal QPA. Instead
of shipping a plugin and loading it dynamically we can use Qt static
plugins.
This should result in slightly faster load times, but also reduce the
number of moving pieces for kwin.
This also prevents anyone outside kwin loading our QPA which wouldn't
have made any sense and just crashed.
A window id generated by WaylandServer may reference an X11 window
with the same id, which can result in undefined behavior.
The main reason why we needed windowId() was because of the task
switcher. However, since tabbox uses internal ids now, the window id
property can be dropped.
On Wayland, a surface must be displayed the same way no matter how the
attached buffer is transformed. In order to guarantee that, we build the
surface-to-buffer matrix, which is used to compute the texture coords.
The surface-to-buffer matrix represents an affine transformation. Thus,
performing linear interpolation between texture coordinates won't end up
in corrupted rendered results. This is the main assumption that we make
during generation of contents window quads. After creating a sub-quad,
the new quad's texture coordinates are computed by interpolating between
the source quad's texture coords.
However, WindowQuad::makeSubQuad() makes a concrete assumption about the
order of texture coords, which might be false if the attached wayland
buffer is rotated 90 or 270 degrees.
This issue went unnoticed after merging the viewporter patches because
the developer who was working on it had been using primarily nested
kwin_wayland for testing purposes. And it appears like kwin schedules
full screen repaints even though it supports buffer age. It still needs
some investigation why that happens.
BUG: 428003
