Using g_thread_join() in _finalize() handlers may result in a deadlock
joining the current thread when the last reference is held by a signal
handler.
e.g.:
error 'Resource deadlock avoided' during 'pthread_join (pt->system_thread, NULL)'
The backtrace looks like this:
[...]
g_thread_join ()
gst_gl_window_finalize ()
gst_gl_window_x11_finalize ()
g_object_unref ()
g_value_unset ()
g_signal_emit_valist ()
g_signal_emit ()
gst_gl_window_send_mouse_event ()
gst_gl_window_mouse_event_cb ()
g_main_dispatch ()
[..]
g_main_loop_run ()
gst_gl_window_navigation_thread ()
g_thread_proxy ()
start_thread ()
clone ()
Makes infinitely more sense and implementation were expecting that behaviour
anyway and would enter a resize, draw, resize, draw, ... cycle instead of only
resizing once.
Don't create many short lived locks/conds in gst_gl_window_send_message. This is
a micro optimization to save a bunch of pthread_* calls which are expensive on
OSX/iOS and possibly other platforms.
Useful when gst_gl_window.c::gst_gl_window_new is not used.
This is the case when using a custom GstGLWindow.
(ex: GstGLWindowGPUProcess from Chromium)
Exposing the navigation thread's main context, GSourceFuncs and structs called
key_event and mouse_event is exposing a bit too much of the internals. Let's
just go with two functions to asynchronously send navigation events on the
window with the same API as the synchronous ones.
- glimagesink needs to be able to resize the viewport on aspect ratio
changes resulting from either caps changes or 3d output mode changes.
- Performing a glViewport outside the GstGLWindow::resize callback
will not have the winsys' stack of viewports required to correctly
place the output frame.
Provide a function to request a resize on the next draw event from the
winsys.
Also track size changes inside the base GstGLWindow class rather
than in each subclass.
https://bugzilla.gnome.org/show_bug.cgi?id=755111
When setting a new window handle, we need to ensure all implementations
will detect the change.
For that we deactivate the context before setting the window handle, then
reactivate the context
https://bugzilla.gnome.org/show_bug.cgi?id=745090
Depending on the platform, it was only ever implemented to 1) set a
default surface size, 2) resize based on the video frame or 3) nothing.
Instead, provide a set_preferred_size () that elements/applications
can use to request a certain size which may be ignored for
videooverlay/other cases.
This thread dispatches navigation events. It is needed to avoid deadlocks
between window backend threads that emit navigation events (e.g. X11/GMainLoop
thread) and consumers of navigation events such as glimagesink, see
https://bugzilla.gnome.org/show_bug.cgi?id=733661
GstGlWindow_x11 thread is changed to invoke the navigation thread for navigation
dispatching, instead of emiting the event itself. Othe backends beside X11 do
not dispatch navigation events yet, but should use this thread when dispatching
these events in the future.
The navigation thread is currently part of GstGLWindow and not implemented in
separate subclasses / backends. This will be needed in the future.
gst_gl_window_x11_get_surface_dimensions is also changed to use a cached value
of the window's width, height. These values are now retrieved in the X11
thread, function gst_gl_window_x11_handle_event. This change is needed because
otherwise the XGetWindowAttributes gets called from the navigation thread,
leading to xlib aborting due to multithreaded access (if XInitThreads is not
called before, as is the case for gst-launch)
If window is resized, GstStructure pointer values have to be rescaled to
original geometry. A get_surface_dimensions GLWindow class method is added for
this purpose and used in the navigation send_event function.
https://bugzilla.gnome.org/show_bug.cgi?id=703486
Effective for the case where we have a platform that does not
require a native window. We require a mainloop to run the GL
commands which is currently operated by GstGLWindow.
GstGLDisplayX11 holds the display connection and name. Each thread requires
it's own X11 Display connection (initialised from name) due to the fact that
we do not want to call XInitThreads(). Doing so would result in segfaults
when integrating with GUI toolkits Gtk, Qt, etc.
The Display connection is for OpenGL platforms where a constant display is
required in order to share contexts (egl). In the case of a wrapped context
(added later), we do not have GstGLWindow to retreive the display from so a
'master' connection is used instead.
