The Linux OpenGL ABI does not guarantee that glXSwapIntervalEXT will be
exported statically from any library, and indeed on some systems this
function does not link at load time, e.g. with amdgpu-pro. All other
GLX functions that we use are from GLX 1.0, which is guaranteed to be
exported statically.
This commit solves this issue by using glXGetProcAddressARB to load the
function. Note that only the ARB version of glXGetProcAddress is
guaranteed to exist by the Linux OpenGL ABI, which is why we must use
it.
External events like launching other applications can cause latency
spikes while X11 initializes the application, we should only start
adjusting our delay if we see excessive skips over a 1s period.
Invalidating the entire window on an Expose event causes poor WM
performance when dragging the window around. Instead flag to redraw and
wait for the expose events to stop for 100ms before doing it.
X11 needs to calibrate to get the best possible latency, as such it
needs the scene to render so that the render time of the scene can be
accounted for in the delay calculation.
XPresent doesn't give us the time before presentation, but the time just
after. This code calculates and calibrates a delay to sleep for before
signaling the wait event for render when using jitRender
The imgui overlay requires input even if the display is not captured and
operating in raw mode. XInput2 correctly only sends
XI_Press/ReleaseButton events if the device has not been captured, as
such it's safe to handle both raw and non raw buttons events at the same
time.
This commit creates a new utility library, eglutil.h, which contains code
to detect and use EGL_KHR_swap_buffers_with_damage or its EXT equivalent.
This logic used to be duplicated between the X11 and Wayland display servers,
which is not ideal.
Drawing to the front buffer directly requires special handling to
prevent seeing the draw progress (avoiding glClear, etc) and as a result
the output is quite bad unless a compositor is running. Also vsync if
enabled will not function without double buffering enabled.
As OpenGL is the legacy fallback, there are no plans to implement clean
front buffer draw support, so just enable double buffering.
The incorrect spelling, NETWM_BYPASS_COMPOSITOR, somehow worked in the
past, but it appears to not work right now. Corrgan on Discord reported
the issue and confirmed that changing the spelling allowed the compositor
to be bypassed and the client to update faster than 60 Hz on his mixed
refresh rate setup.
Instead of damaging the entire surface when rendering a cursor move,
we can use the EGL_KHR_swap_buffers_with_damage extension to only
damage the part of the window covered by the cursor. This should
reduce the cursor movement latency on Wayland.
We previously used strstr, which can be prone to false positives when
the name of one extension is a substring of another extension.
This commit creates the helper function util_hasGLExt, which asserts
that the substring found in extension list is bounded by either spaces
or the beginning/end of the string.
Using util_cursorToInt messes with the error tracking for normal movements,
and is not necessary since we are computing an absolute position on the
client window.
Instead, we should pass doubles directly to display servers and let them
decide how to best handle them. For example, XIWarpPointer accepts doubles
directly.
Currently, (un)grabPointer is used both for tracking/confining the mouse
in normal mode, as well as entering/exiting capture mode. This makes it
impossible to use separate cursor logic for capture mode, which is needed
to deal with overlapping windows for the Wayland backend.
This commit creates separate (un)capturePointer for entering/exiting
capture mode. There should be no behaviour changes.
This adds a new method to the display server interface to allow the
application to notify the ds when there is a guest cursor position
update along with the translated local guest cursor position. This makes
it possible for the display server to keep the local cursor position in
sync with the guest cursor so that window leave events can be detected
when the cursor would move into an overlapping window.
Wayland currently just has a stub for this, and the X11 implementation
still needs some minor tweaking.
Due to the logic in the event loop property events may get filtered out
that were clipboard related. This changes ensures the clipboard event
handler code gets to run first avoiding this issue.
If the window manager does not support the motif hints then fallback to
creating a utility window, do not do both. A utility window is a
sub-optimal fallback as it may prevent the application being shown in
the taskbar or as a running application as has been reported on KDE.
Using the first two valuators present in the event is incorrect. Events
with only one valuator set, such as those sent by the Xorg evdev driver
when the mouse moved along one axis only, were being discarded. On the
other hand, mice with multiple scroll wheels may be able to emit events
with two scroll wheel valuators set.
The XInput2 specification is light on details, but "Rel X" and "Rel Y"
appear to be the de facto standard names for the motion valuators. If
valuators with those labels are not found, fall back to using valuators
with numbers 0 and 1.
