Summary:
So far SharingPlatformContext was only used if the OpenGL context
supports EGL_KHR_surfaceless_context. If not supported, KWin tried to
create a context through the Wayland API. Unfortunately on hwcomposer
platform this results in a crash as libhybris only supports the init
of EGLDisplay for one native platform.
This change tries to also use the SharingPlatformContext if there is
an OpenGL context in general. It reuses the native EGLSurface created
for the compositing scene and makes its own OpenGL context current on
that surface, too. As KWin creates an FBO, it never renders to it, so
it shouldn't matter at all.
In order to prevent EGL_BAD_MATCH errors when making Qt's OpenGL context
current also the EGLConfig from the scene is used to create the context.
Test Plan: Tested on Nexus5 with qtvirtualkeyboard in KWin
Reviewers: #kwin, #plasma_on_wayland
Subscribers: plasma-devel, kwin
Tags: #plasma_on_wayland, #kwin
Differential Revision: https://phabricator.kde.org/D2231
This introduces an own QPA plugin for KWin. QtWayland's plugin is not
a good solution for KWin as QtWayland is meant for Wayland clients and
not for a Wayland server. Given that it makes more sense to have a very
minimal QPA plugin which supports the use cases we actually have.
With our own QPA plugin we should be able to improve the following
areas:
* no need to create Wayland server before QApplication
* Qt::BypassWindowManagerHint can be supported
* no workaround for creating OpenGL context in main thread
* sharing OpenGL context with Qt
* OpenGL context for Qt on libhybris backend
The plugin supports so far the following features:
* creating a QPlatformWindow using KWayland::Client (ShellSurface)
* creating a QPlatformBackingStore using a ShmPool
* creating a QPlatformOpenGLContext with Wayland::EGL
* or creating a QPlatformOpenGLContext which shares with KWin's scene
* creating a QPlatformScreen for each KWayland::Client::Output
* QPlatformNativeInterface compatible to QtWayland
