This adds support for OpenGL to the GDK Windows backend using the WGL API
calls, which enables programs that uses the GTK+ GLArea widgets to work on
Windows as well.
This also adds a simple utility function to query for the version of OpenGL
that is supported by the Windows system, like the one provided by the X11
backend.
Many thanks to Alex (and Emmanuele, who started the OpenGL integration in
GTK+) who offered advice and help along the way, as well as the X11 and
Wayland backend for this work to refer to and to model upon.
https://bugzilla.gnome.org/show_bug.cgi?id=740795
As the alignments, strides and image formats may be different across
platforms, make the texture upload a vfunc to allow backends to override
the GL commands for uploading textures for the software implementation for
gdk_gl_texture_from_surface(), if necessary.
Suggested by Alex to avoid copying non-trivial portions of code which would
then add maintainenace burden.
https://bugzilla.gnome.org/show_bug.cgi?id=740795
We can't combine multiple draws into one for the software fallback,
because each quad has a different texture. And we generally don't
want to make a larger single texture because then we would have
to upload more data.
The ICCCM says:
If the specified property is None , the requestor is an obsolete client.
Owners are encouraged to support these clients by using the specified
target atom as the property name to be used for the reply.
Lets do that, instead of crashing.
https://bugzilla.gnome.org/show_bug.cgi?id=740613
NULL-plus-something could be seen by the compiler to attempt to do
arithmetic with void *, which is a GCCism. Instead, do the math normally
and cast the results as a void *.
https://bugzilla.gnome.org/show_bug.cgi?id=740605
Use xdg_surface_set_window_geometry() to tell the compositor about the
shadow widths, this makes some gnome-shell/mutter features (edge resistance,
frames around windows in the overview, side maximization, ...) work alright
with GTK+.
In order to add this, some other places in gdkwindow-wayland had to gain
some knowledge about margins:
- xdg_surface_configure() now syncs the shadow after applying the state,
and gdk_wayland_window_set_shadow_width() possibly reconfigures the
window in order to preserve window geometry. This is necessary to keep
shadows in sync with state/geometry changes, as this does not happen
all at once.
- xdg_popups relative to an xdg_surface are shown relative to buffer
coordinates, so the left/top margins must be added there.
https://bugzilla.gnome.org/show_bug.cgi?id=736742
This requires us to use GL_TRIANGLES and six verts per quad instead
of four, which makes me think it might not be worth it on
well-optimized GL drivers. However, from talking to some driver
developers about it, the GL_TRIANGLES should be faster, since this
means that there's one giant contiguous buffer instead of many small
buffers.
If we were really rendering a lot of quads, I'd use an element buffer
and GL_PRIMITIVE_RESTART, but we're really not ever rendering that
many quads, and the setup cost for that would just be too annoying.
It's unused. At the same time, rename "begin_paint_region" to
"begin_paint". This will help us clean up how GDK painting works
in the future to allow more creative use of double-buffering.
This is needed in the edge case where the X11 backend rounded the actual
size, and the GL flipping really needs the correct window height to
do proper Y coordinate flipping.
https://bugzilla.gnome.org/show_bug.cgi?id=739750
This is required for the X backend GL integration. If the
window has a height that is not a multiple of the window scale
we can't properly do the y coordinate flipping that GL needs.
Other backends can ignore this and use the default implementation.
https://bugzilla.gnome.org/show_bug.cgi?id=739750
Rather than just rounding down the position *and* the size separately
we correctly calculate a rectangle in scaled window coords that fully
covers the real window size. This really only makes a difference
when the window size/position isn't a multiple of the window scale.
https://bugzilla.gnome.org/show_bug.cgi?id=739750
Keep track of the exact size of X windows in underlying pixels; we
generally use the scaled size instead, but to properly handle the GL
viewport for windows that aren't a multiple of window_scale,
we need to know the real size.
https://bugzilla.gnome.org/show_bug.cgi?id=739750
Although we specify a resize increment to try and get a size that is
a multiple of the window scale, maximization typically wins
over the resize increment, so the window might be odd sized.
Round *up* in this case, rather than down, since it's better to
truncate a line or two at the bottom and right of the window rather
than have a line or two that we don't know what to do with.
https://bugzilla.gnome.org/show_bug.cgi?id=739750
