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.
This function can be used to find the GdkDevice wrapping
an XInput2 device ID. For core devices, the Virtual Core
Pointer/Keyboard IDs (2/3) may be used.
This function can be used to find out the XInput2 device ID
behind a GdkDevice, mostly useful when you need to interact
with say Clutter, or raw libXi calls.
Move everything dealing with compound text to be X11 specific
Only gdk_text_property_to_utf8_list and gdk_utf8_to_string_target
are kept across backends, so add vfuncs for these.
Also, remove the non-multihead-safe variants of all these.
Moving the direct-access redefinitions of various macros
to gdkprivate-x11.h and use that header throughout in x11/.
Also remove a workaround for a long-fixed X server bug.
The X11 backend exports a number of symbols which are _-prefixed
(so don't become part of the gdk api), but are not named in a
way to prevent accidental clashes between backends.
The one API change here is that the gdk_xid_table functions
have been removed - they did not server an purpose, since the
xid table only stores windows anyway, and we already have a
lookup-by-xid function for windows.
Also add a priv pointer to GdkVisual and use it for the GdkVisualPrivate
structure. Then Make GdkVisualPrivate actually private to
gdkvisual-x11.c and make other callers use proper function calls to
access it.
* add per-display gdk_x11_display_error_trap_push()
(X11-specific because gdk_error_trap_push() probably
should have been)
* make gdk_error_trap_push() handle only GDK displays
not displays opened without a GDK wrapper
* make gdk_error_trap_pop() and gdk_x11_display_error_trap_pop()
automatically sync only if needed, so manual gdk_flush() is not
required
* add gdk_error_trap_pop_ignored() which just asynchronously
ignores errors, so never needs to sync
* add G_GNUC_WARN_UNUSED_RESULT to plain pop(), because
if you use plain pop() and don't need the return value,
the async gdk_error_trap_pop_ignored() should be used
instead. This results in lots of warnings to clean
up in a later patch.
The main objective here was to avoid the need to sync just
to ignore an error. Now, syncing is automatic, and only
happens when we need to know the error code.
https://bugzilla.gnome.org/show_bug.cgi?id=629608
This was the last exported variable; it wasn't multihead safe,
and there's easy replacement with gdk_display_get_default().
Also drop the GDK_DISPLAY() macro which was just a wrapper around
the variable.
