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Wayland documentation: further details about throttling window redraws

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ManoloFLTK 2024-05-22 13:13:29 +02:00
parent df3c875453
commit 614d551d05
1 changed files with 9 additions and 6 deletions
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documentation/src/wayland.dox
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@ -650,9 +650,8 @@ changed and needs being committed. This variable is turned \c true every time a
graphics operation changes the buffer content and turned \c false when the
buffer gets committed.
This procedure ensures that FLTK never changes the surface's Wayland buffer
while it's being used by the compositor and never calls \c wl_surface_commit()
before Wayland gets ready for a new commit because
This procedure ensures that FLTK never calls \c wl_surface_commit()
before the compositor becomes ready for a new commit because
\c Fl_Wayland_Window_Driver::flush() calls
\c Fl_Wayland_Graphics_Driver::buffer_commit() only if \c frame_cb is NULL.
If it's not NULL, the exact content of function \c surface_frame_done() :
@ -667,9 +666,8 @@ static void surface_frame_done(void *data, struct wl_callback *cb, uint32_t time
}
\endcode
has the effect that when the mapping operation eventually completes, Wayland runs
\c surface_frame_done(), which calls anew
\c Fl_Wayland_Graphics_Driver::buffer_commit() if the buffer's
\c draw_buffer_needs_commit member is true. The net result is that the screen
\c surface_frame_done(), which, if the buffer's \c draw_buffer_needs_commit member is true,
calls \c Fl_Wayland_Graphics_Driver::buffer_commit() anew. The net result is that the screen
shows the most recent surface content.
This synchronization mechanism is also used when performing an interactive window resize
@ -1242,6 +1240,11 @@ Wayland uses <a href=https://www.khronos.org/api/egl>EGL™</a> to interface Ope
native platform window system. OpenGL-using FLTK apps are therefore linked to \c libwayland-egl.so and
\c libEGL.so in addition to \c libGL.so and \c libGLU.so.
EGL completely hides the \c wl_buffer objects it uses to draw to GL windows.
The \ref wld_buffer structure and the 'buffer factory' described previously are not used for
\c Fl_Gl_Window's : the \c buffer member of an \c Fl_Gl_Window's \ref wld_window structure is
always NULL.
EGL is initialized calling member function \c Fl_Wayland_Gl_Window_Driver::init()
once, the first time the \c Fl_Wayland_Gl_Window_Driver c'tor runs. That is done
with calls to <tt>eglGetDisplay(), eglInitialize()</tt>, and \c eglBindAPI().