Allows callers to properly reference count the buffers used for
rendering.
Fixes a redraw race in glimagesink where the previous buffer
(the one used for redraw operations) is freed as soon as the next
buffer is uploaded.
1. glimagesink uploads in _prepare() to texture n
1.1 glupload holds buffer n
2. glimagesink _render()s texture n
3. glimagesink uploads texture n+1
3.1 glupload free previous buffer which deletes texture n
3.2 glupload holds buffer n+1
4. glwindow resize/expose
5. glimagesink redraws with texture n
The race is that the buffer n (the one used for redrawing) is freed as soon as
the buffer n+1 arrives. There could be any amount of time and number of
redraws between this event and when buffer n+1 is actually rendered and thus
replaces buffer n as the redraw source.
https://bugzilla.gnome.org/show_bug.cgi?id=736740
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)
EGL_CONTEXT_FLAGS_KHR and EGL_CONTEXT_OPENGL_DEBUG_BIT_KHR
don't exist in the Android NDK. Wrap their usage in an #ifdef
EGL_KHR_create_context to fix the build there.
The text for EGL_KHR_create_context added the possiblity for ES
contexts to ask for a debug context however that has not been
fully realized by all implementations. Fallback to a non-debug
context when the implementation errors.
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
Certain elements expect that there be a certain number of lines
that they can write into. e.g. for odd heights, I420, YV12, NV12,
NV21 (and others) Y lines are expected to have exactly twice the
number of U/UV lines.
https://bugzilla.gnome.org/show_bug.cgi?id=733717
We cannot do it as the winsys may crash if we initialize too late.
Example, GLX contexts with Intel drivers:
Intel requires the X Display to be the same in order to share GL
resources across GL contexts. These GL contexts are generally
accessed from different threads. Without winsys support it is
nearly impossible to guarentee that concurrent access will not
occur. This concurrent access could result in crashes or abortion
by the winsys (xcb).
https://bugzilla.gnome.org/show_bug.cgi?id=731525
