gcc -Wimplicit-fallthrough only detects comments if they are immediately
preceded before the next label. Braces stops it from recognizing the
fallthrough comment.
This makes it a compile-time error to call a function that semantically
takes no parameters with a nonzero number of arguments.
Previously, such code would still compile, but risk blowing up the stack
if a compiler chose to use something other than caller-cleanup calling
conventions.
eglSwapBuffers is allowed to block when called with a nonzero interval
parameter. On Wayland, Mesa will block until a frame callback arrives.
If an application is not visible, a compositor is free to not schedule
frame callbacks (in order to save CPU time rendering something that is
entirely invisible).
Currently, starting Looking Glass from a terminal, hiding it
entirely, and sending ^C will cause Looking Glass to hang joining the
render thread until the window is made visible again.
Calling eglDestroySurface is insufficient to unblock eglSwapBuffers, as
it attempts to grab the same underlying mutex.
Instead, this commit makes it so that we pass a 0 interval to
eglSwapBuffers when running on Wayland, such that we don't block waiting
for a frame callback. This is not entirely ideal as it *does* mean
Looking Glass submits buffers while hidden, but it seems better than
hanging on exit.
It also forces opengl:vsync and egl:vsync flags to off when running on
Wayland, as they are meaningless there.
Note: This only works with the KVMFR kernel module in a VM->VM
configuration. If this causes issues it can be disabled with the new
option `app:allowDMA`
This changes the method of the memory copy from the host application to
the guest. Instead of performing a full copy from the capture device
into shared memory, and then flagging the new frame, we instead set a
write pointer, flag the client that there is a new frame and then copy
in chunks of 1024 bytes until the entire frame is copied. The client
upon seeing the new frame flag begins to poll at high frequency the
write pointer and upon each update copies as much as it can into the
texture.
This should improve latency but also slightly increase CPU usage on the
client due to the high frequency polling.
