This is because we keep track of the top-left corner of the cursor, not
the location of the hotspot. When the cursor shape changes, the hotspot
location may also change. When it does, the position of the top-left
corner changes and requires an update.
In the case that we do not have the current cursor position, which
happens on startup, we do not generate this update.
We are forced to use accelerated movement in regular mode as that is how the
host machine cursor moves and we want the cursors to line up (since Wayland
cannot do warps). To avoid a change in sensitivity when toggling capture
mode on/off, we should use accelerated deltas for capture mode as well,
unless the user explicitly asks for raw input with input:rawMouse.
NvFBC is unable to capture certain applications that bypasses the DWM
compositor, for example, Firefox playing video in full screen. This
has been a known issue for a long time with Nvidia's ShadowPlay, see:
* https://www.nvidia.com/en-us/geforce/forums/geforce-experience/14/233709/
* https://crbug.com/609857
Nvidia won't fix this, but there are workarounds. For example, we
create a transparent 1x1 layered window, which forces desktop composition
to be enabled.
Note that SetLayeredWindowAttributes also supports alpha-based transparency,
but setting transparency to 0 will cause DWM to skip composition. We could
use a transparency of 1, but this ruins the image by the slightest bit,
which is unacceptable. Therefore, we must use chroma key-based
transparency, which tricks DWM into compositing despite being fully
transparent.
It does not make sense to accumulate fractional error in non-capture mode
as you know exactly where the cursor is supposed to be, at least on Wayland.
On Wayland, we base movements on the current guest position and desired
target position, and the accumulated errors only skew our movements.
Build failed with _FORTIFY_SOURCE enabled because the compiler couldn't
ensure the switch statements didn't hit the default arm and thus wouldn't
define the variables. Adding a statically failing assert makes sure that
all code paths either define the variables or fail early.
$ cd client
$ env CFLAGS='-O1 -D_FORTIFY_SOURCE=1' cmake -B build/
$ make -C build
[...]
client/renderers/EGL/egl.c: In function ‘egl_calc_mouse_size’:
client/renderers/EGL/egl.c:299:36: error: ‘h’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
299 | (this->mouseHeight * (1.0f / h)) * this->scaleY
| ~~~~~~^~~~
