Similar to what has been done recently for DESKTOP_AUTOSTART_ID [1],
we need to get rid of this call to g_unsetenv() in the displays'
backends for X11 and Wayland, so that it's guarantee to happen any
thread is created, while still being accessible when needed.
Let's stash the value of this environment variable when loading the
GDK library, and provide a private method so that it can be retrieved
from the displays' backend when implementing gdk_display_make_default().
[1] https://gitlab.gnome.org/GNOME/gtk/commit/22269902
Closes: https://gitlab.gnome.org/GNOME/gtk/issues/979
We can't really support these on e.g. wayland anyway, and we're trying
to get rid of subwindow at totally in the long term, so lets drop this.
It allows us to drop a lot of complexity.
Adds the gdk_display_ref_vulkan() and gdk_display_unref_vulkan()
functions which setup/tear down VUlkan support for the display.
Nothing is using those functions yet.
Even when the program itself calls gdk_set_program_class(). There's
currently no way for this function to be called without breaking gdk's
--class command line option, because you cannot call it before
gtk_init().
https://bugzilla.gnome.org/show_bug.cgi?id=747634
The current way of exposing GDK API that should be considered internal
to GTK+ is to append a 'libgtk_only' suffix to the function name; this
is not really safe.
GLib has been using a slightly different approach: a private table of
function pointers, and a macro that allows accessing the desired symbol
inside that vtable.
We can copy the approach, and deprecate the 'libgtk_only' symbols in
lieu of outright removal.
https://bugzilla.gnome.org/show_bug.cgi?id=739781
This moves the GDK_ALWAYS_USE_GL env var to GDK_GL=always.
It also changes GDK_DEBUG=nogl to GDK_GL=disable, as GDK_DEBUG
is really only about debug loggin.
It also adds some completely new flags:
software-draw-gl:
Always use software fallback for drawing gl content to a cairo_t.
This disables the fastpaths that exist for drawing directly to
a window and instead reads back the pixels into a cairo image
surface.
software-draw-surface:
Always use software fallback for drawing cairo surfaces onto a
gl-using window. This disables e.g. texture-from-pixmap on X11.
software-draw:
Enables both the above.
This is mostly useful for fallback testing.
I suppose if people want finer grained GL ability testing, they can use
Mesa environment variables to tune things.
This adds the new type GdkGLContext that wraps an OpenGL context for a
particular native window. It also adds support for the gdk paint
machinery to use OpenGL to draw everything. As soon as anyone creates
a GL context for a native window we create a "paint context" for that
GdkWindow and switch to using GL for painting it.
This commit contains only an implementation for X11 (using GLX).
The way painting works is that all client gl contexts draw into
offscreen buffers rather than directly to the back buffer, and the
way something gets onto the window is by using gdk_cairo_draw_from_gl()
to draw part of that buffer onto the draw cairo context.
As a fallback (if we're doing redirected drawing or some effect like a
cairo_push_group()) we read back the gl buffer into memory and composite
using cairo. This means that GL rendering works in all cases, including
rendering to a PDF. However, this is not particularly fast.
In the *typical* case, where we're drawing directly to the window in
the regular paint loop we hit the fast path. The fast path uses opengl
to draw the buffer to the window back buffer, either by blitting or
texturing. Then we track the region that was drawn, and when the draw
ends we paint the normal cairo surface to the window (using
texture-from-pixmap in the X11 case, or texture from cairo image
otherwise) in the regions where there is no gl painted.
There are some complexities wrt layering of gl and cairo areas though:
* We track via gdk_window_mark_paint_from_clip() whenever gtk is
painting over a region we previously rendered with opengl
(flushed_region). This area (needs_blend_region) is blended
rather than copied at the end of the frame.
* If we're drawing a gl texture with alpha we first copy the current
cairo_surface inside the target region to the back buffer before
we blend over it.
These two operations allow us full stacking of transparent gl and cairo
regions.
Since GLib ≥ 2.41, attempting to release an unlocked mutex will abort(),
as it happens on most systems already.
Given the lack of proper documentation on how to use GDK with threads,
there is code in the wild that does:
gdk_threads_init ();
gdk_init ();
...
gtk_main ();
instead of the idiomatically correct:
gdk_threads_init ();
gdk_threads_enter ();
gtk_init ();
...
gtk_main ();
...
gdk_threads_leave ();
Which means that gtk_main() will try to release the GDK lock, and thus
trigger an error from GLib.
we cannot really fix all the wrong code everywhere, and since it does
not cost us anything, we can work around the issue inside GDK itself, by
trying to acquire the GDK lock inside gdk_threads_leave() with
trylock().
https://bugzilla.gnome.org/show_bug.cgi?id=735428
