The egl wayland backend registers for the callback for a rendered frame.
This allows to throttle KWin's compositor so that we don't render frames
which wouldn't end up on the screen.
For this the Scene provides a method to query whether the last frame got
rendered. By default this returns true in all backends. The Egl Wayland
backend returns true or false depending on whether the callback for the
last frame was recieved.
In case the last frame has not been renderd when performCompositing is
tried to be called, the method returns just like in the case when the
overlay window is not visible. Once the frame callback has been recieved
performCompositing is invoked again.
The backend gets created by Workspace, but only if the environment
variable WAYLAND_DISPLAY is set.
Because of that the egl wayland backend does no longer create the
backend, but uses the already created one.
The functionality to create the connection to a Wayland compositor and
creating a fullscreen surface is moved into wayland_backend.(h|cpp). The
wl_egl_window for the surface is moved into the EglWaylandBackend to have
the actual WaylandBackend free from Egl. This will allow in future to
implement other compositing backends for Wayland which do not use egl.
This means that egl is no longer a build requirement for the wayland
related functionality.
* Find Wayland was missing in CMakeLists.txt
* Wayland Backend is adjusted for new virtual methods (makeCurrent, doneCurrent)
* Buffer Age is implemented
With QtQuick2 KWin is no longer the only one having an OpenGL context
thus we need to ensure that our context is current. If not it results in
highly interesting crashes when our code is executed on the QtQuick
context.
The context is made current before we swap and before we start to render
a frame. During rendering a frame it's not made current again based on
the assumption that while we render there is no interference. If this
assumption doesn't hold, we need a more sophisticated solution at the
moment it seems to fix the crashes.
Nicely integrates Qt's event loop with the Wayland event handling.
We still need to dispatch pending events before calling eglSwapBuffers as
that call might block.
Tracking cursor changes in X11. Whenever the cursor image changes, the
image is read and a wl_buffer is created with the content of the X11
cursor. This buffer is attached to a surface used as a cursor image.
As a memory pool for the cursor buffers a temporary file is created and
mmapped.
All created cursors are cached but not yet removed from the cache. Some
cleanup code would be useful also to ensure that our shared memory pool
doesn't overflow.
Rudimentary support for input events. Events from Wayland are forwarded
to X's root window using the XTest extension.
Currently supported:
* left/middle/right mouse button
* keyboard events
Not supported:
* additional mouse buttons
* mouse wheel
* touch events
Obviously this is a rather huge hack and is only intended till we have
XWayland support and proper input redirection inside KWin.
This backend is able to composite on a Wayland surface instead of an X11
overlay window. It can be considered as a prototype for a Wayland session
compositor.
For texture from X11 pixmap the backend uses XShm. This is far from
optimal, but the KHR_image_pixmap extension is not available in Mesa's
Wayland backend. It's a temporary solution till we have XWayland and
texture from Wayland buffer.
To use this backend one needs to specify the environment variable
KWIN_OPENGL_INTERFACE with "egl_wayland". In future KWin should probably
use this backend if the Wayland display env variable is defined.
To use this setup:
1. Have a normal X-Server running on e.g. VT7
2. Start Weston on VT1
3. Start a terminal on Weston
4. start KWin with:
DISPLAY=:0 KWIN_OPENGL_INTERFACE=egl_wayland kwin --replace &
This should map a Wayland surface to Weston showing the content of the X
setup. At the moment it's not yet possible to interact with the surface
as input events are not yet recieved in the backend.
There are still a lot of limitations as documented in the code.
