Here's an IRC dump that hopefully explains the issue this fixes:
> I'm debugging something odd where, for a libre game,
unvanquished.net (a FPS), relative mouse input in fullscreen is
buggy
> it's like, working mostly ok, but it has a weird
performance/cleanup bug
> after some time in relative mouse input mode, some time as low
as 15s, usually more, the SDL sends A LOT of relative mouse
input per frame
> almost all of which have xrel==0 && yrel==0
> by A LOT, I mean that after ~1min, it's usually in the
thousands per frame
> each frame, a while ( SDL_PollEvent( &e)) loop reads the
inputs, but it seems SDL is not clearing the list.
> one way to clear the list is to open the in-game console or
menu, which switches the input mode to absolute, then close it
which gets a working relative input mode (for some time at least)
> I've shown the issue to be present with SDL2.0.20 but not with
2.0.14 on my system
> some other players on Arch Linux (SDL2.0.20) report a possibly
related issue, where some keys seem to be pressed at random
> I've did some bisection on SDL master, and I've found that
there are actually two commits involved, one breaking it
totally (no input at all), and one fixing it partially (with
the problem described above)
First related commit that breaks it totally:
commit 82793ac279
Author: Sam Lantinga <slouken@libsdl.org>
Date: Thu Oct 14 14:26:21 2021 -0700
Fixed mouse warping while in relative mode
We should get a mouse event with an absolute position and no relative motion and shouldn't change the OS cursor position at all
Second related commit, that halfway fixes it:
commit 31f8c3ef44
Author: Sam Lantinga <slouken@libsdl.org>
Date: Thu Jan 6 11:27:44 2022 -0800
Fixed event pump starvation if the application frequently pushes its own events
Reverting the first commit did fix the issue for me, but would
probably reintroduce the bug it was fixing(?). This patch should
fix it for everyone hopefully.
https://github.com/DaemonEngine/Daemon/issues/600 is the upstream
bug, and contains some early investigation.
According to MSDN, we can also get SIZE_MAXHIDE and SIZE_MAXSHOW,
based on state changes to other windows. It's not clear under
what circumstances this will happen (I saw some docs indicating
it may require multiple application windows), but it doesn't seem
right to treat them as RESTORED.
- no need to keep the error in a static variable
- always print the error code
- reduce the required stack-size
- reduce the number of snprintf calls (and code size)
* Fixes for IME Composition Truncation + Addition of SDL_ClearComposition, SDL_IsTextInputShown
* Fixed: Documentation and code style issues raised during code review.
The name that the Raw Input joystick driver pulls from the HID stack comes
from USB string descriptors contained on the device. For official wireless
receivers, this always contains "Xbox 360 Wireless Receiver for Windows"
which matches the friendly name that WGI provides.
3rd party Xbox 360 wireless receivers may have different strings in their
USB string descriptors (one uses "XBOX 360 For Windows" instead). This
fails to match WGI's name and causes Raw Input and WGI to both report the
same gamepad.
Since wireless Xbox 360 controllers seem to have a consistent VID/PID
regardless of the adapter enumerating them, we can also match on that to
catch these.
The duplicate case reported to me was:
Controller (XBOX 360 For Windows) - 030000005e040000a102000000007200
Xbox 360 Wireless Receiver for Windows - 030000005e0400000000000000007701
Sam Lantinga