it used to place zeroes between the sign and the number. (space-padding
from within SDL_PrintString() seems OK: spaces are added before sign.)
also fixed the maxlen handling if the number has a sign.
Sylvain
Patch a few warnings when using:
-Wmissing-prototypes -Wdocumentation -Wdocumentation-unknown-command
They are automatically enabled with -Wall
- remove force-enabling of pad_zeroes for %u for compatibility
(was added in https://hg.libsdl.org/SDL/rev/701f4a25df89)
- ignore pad_zeroes for %s and %S
- ignore pad_zeroes for %d, %i and %u if a precision is given
Alexei
On WM_WINDOWPOSCHANGED event, WIN_UpdateClipCursor() is called. SDL_WINDOW_INPUT_FOCUS is set even when the mouse pointer is not inside the SDL window and therefore ClipCursor(&rect) is called. When dragging the window and rect.bottom=800 (i.e. the bottom edge of the screen) the SDL window is clipped to the bottom of the screen and it is not possible to move it back to the center of the screen.
Anthony @ POW Games
SDL_CreateTextureFromSurface makes an internal call to SDL_GetColorKey which can return an error and spams the error log with "Surface doesn't have a colorkey" even though the original function didn't return an error.
src/joystick/hidapi/SDL_hidapijoystick.c: In function 'HIDAPI_InitializeDiscovery':
src/joystick/hidapi/SDL_hidapijoystick.c:281: error: 'true' undeclared (first use in this function)
src/joystick/hidapi/SDL_hidapijoystick.c:281: error: (Each undeclared identifier is reported only once
src/joystick/hidapi/SDL_hidapijoystick.c:281: error: for each function it appears in.)
src/joystick/hidapi/SDL_hidapijoystick.c: In function 'HIDAPI_UpdateDiscovery':
src/joystick/hidapi/SDL_hidapijoystick.c:339: error: 'true' undeclared (first use in this function)
src/joystick/hidapi/SDL_hidapijoystick.c:341: error: ISO C90 forbids mixed declarations and code
The previous code attempted to use set_buffer_size / set_period_size
discretely, favoring the parameters which generated a buffer size that was
exactly 2x the requested buffer size. This solution ultimately prioritizes
only the buffer size, which comes at a large performance cost on some machines
where this results in an excessive number of periods. In my case, for a 4096
sample buffer, this configured the device to use 37 periods with a period size
of 221 samples and a buffer size of 8192 samples. With 37 periods, the SDL
Audio thread was consuming 25% of the CPU.
This code has been refactored to use set_period_size and set_buffer_size
together. set_period_size is called first to attempt to set the period to
exactly match the requested buffer size, and set_buffer_size is called second
to further refine the parameters to attempt to use only 2 periods. The
fundamental change here is that the period size / count won't go to extreme
values if the buffer size can't be exactly matched, the buffer size should
instead just increase to the next closest multiple of the target period size
that is supported. After changing this, for a 4096 sample buffer, the device
is configured to use 3 periods with a period size of 4096 samples and a buffer
size of 12288 samples. With only 3 periods, the SDL Audio thread doesn't even
show up when profiling.
Fixes Bugzilla #4156.
"Applications (such as SDL's testgesture) do "event.tfinger.x * window_width"
to find window coord. Currently the X11 XInput2 backend expects application
to do "event.tfinger.x * (window_width-1)" instead.
X11 XInput2 touch events are normalized so x is 1.0 at "width - 1" but other
SDL backends appear to have x be 1.0 at "width". Same issue for touch event
y with regards to height."
Fixes Bugzilla #4183.
If we change the current context behind the app's back, those tracking
the current context to minimize context changes are going to get
confused.
This brings the EGL backend in line with the GLX one.
Fixes Bugzilla #4199.
This was reproducible by running an SDL app on the console from an ssh login. In this case the terminal wasn't owned by the user running the app, so we were using the default keymap, which didn't have state transitions defined for ctrl and alt, so once we entered that state keypresses would no longer transition out of that state, nor would they generate text.
As a workaround, we'll just reset to the default shift state if that happens, which means we'll get text for keys pressed while ctrl is held down, but I don't think that's a big problem.
Note that in this case we also can't mute the keyboard, so the keypresses go to the console, which probably isn't what you want...
SDL_ExitProcess(), SDL_AbortAssertion() and SDLTest_BailOut().
(Commit 303c1e0fb0cf for bug #4100 removed SDL_NORETURN from
SDL_ExitProcess() and SDL_AbortAssertion() in order to avoid
warnings from windows builds, but that's temporary I guess..)
These are entirely untested
Several USB ids refer to multiple packaged products. In those cases I tried to use the most common name, or a general name (e.g. PS3 Controller), or a completely generic name (e.g. USB gamepad) if it wasn't clear what type of controller it was.
Patches welcome!
Expand SDLActivity::SDLSurface::surfaceChanged() callback to grab the panel width and height at the same time and pass that along to the native code. Only works on API 17+. Duplicates surface dimensions whenever it fails.
Add Android_DeviceWidth/Android_DeviceHeight globals to native code.
Disambiguate Android_ScreenWidth/Android_ScreenHeight -> Android_SurfaceWidth/Android_SurfaceHeight
Use device width/height for all display mode settings.
This means we have to consider SDL_WINDOW_MINIMIZED a window creation flag, but on non-windows platforms we just remove it and let the normal FinishWindowCreation re-apply and do the minimize as I have no idea what is right on them or if anything should change.
CR: Phil
Martin ?irokov
Launching an SDL application with SDL_AUDIODRIVER=jack, and then calling SDL_OpenAudioDevice() with whatever parameters fails with an error like this one:
SDL_OpenAudioDevice: Couldn't connect JACK ports: SDL:sdl_jack_output_0 => system:midi_playback_1
This happens because JACK_OpenDevice in src/audio/jack/SDL_jackaudio.c blindly tries to connect to all input ports without checking whether they are for audio or midi.
The fix is to check port types and ignore all non audio ports. Also I removed devports field from struct SDL_PrivateAudioData, because it's never really used and removing unused ports from it would be PITA.
Jona
The following explains why this bug was happening:
This crash was caused because the audio session was being set as active [session setActive:YES error:&err] when the audio device was actually being CLOSED. Certain cases the audio session being set to active would fail and the method would return right away. Because of the way the error was handled we never removed the SDLInterruptionListener thus leaking it. Later when an interruption was received the THIS_ object would contain a pointer to an already released device causing the crash.
The fix:
When only one device remained open and it was being closed we needed to set the audio session as NOT active and completely ignore the returned error to successfully release the SDLInterruptionListener. I think the user assumed that the open_playback_devices and open_capture_devices would equal 0 when all of them where closed but the truth is that at the end of the closing process that the open devices count is decremented.
(It gets upset at the -2147483648, thinking this should be an unsigned value
because 2147483648 is too large for an int32, so the negative sign upsets the
compiler.)
The concern is that a massive int sample, like 0x7FFFFFFF, won't fit in a
float32, which doesn't have enough bits to hold a whole number this large,
just to divide it to get a value between 0 and 1.
Previously we would convert to double, to get more bits, do the division, and
cast back to a float, but this is expensive.
Casting to double is more accurate, but it's 2x to 3x slower. Shifting out
the least significant byte of an int32, so it'll definitely fit in a float,
and dividing by 0x7FFFFF is still accurate to about 5 decimal places, and the
difference doesn't appear to be perceptable.
Fixes problems launching Firewatch on Linux (which statically links SDL but
also dynamically loads a system-wide copy from a plugin shared library) with
a newer SDL build.
The change makes sure that SDL_vsnprintf() nul terminates if it is
using _vsnprintf() for the job.
I made this patch for Watcom, whose _vsnprintf() doesn't guarantee
nul termination. The preprocessor check can be extended to windows
in general too, if required.
Closes bug #3769.
Daniel Gibson
Sorry, but it seems like Microsoft didn't fix the issue properly.
I just updated my Win10 machine, it now is Version 1803, Build 17134.1
I tested with SDL2 2.0.7 (my workaround was released with 2.0.8) and still got
lots of events that directly undid the prior "real" events - just like before.
(See simple testcase in attachement)
By default it sets SDL_HINT_MOUSE_RELATIVE_MODE_WARP - which triggered (and on my machine still triggers) the buggy behavior. You can start it with -raw, then it'll not set that hint and the events will be as expected.
The easiest way to see the difference is looking at the window title, which shows accumulated X and Y values: If you just move your mouse to the right, in -raw mode the number just increases. In non-raw mode (using mouse warping) it stays around 0.
I also had a WinAPI-only testcase: https://gist.github.com/DanielGibson/b5b033c67b9137f0280af9fc53352c68
It just calls SetCursorPos(320,240); on each WM_MOUSEMOVE event, and it also
logs all those events to a mouseevents.log textfile.
This log indeed looks a bit different since the latest Win10 update: It seems like all those events with x=320 y=240 do arrive - but only after I stopped moving the mouse - even though the cursor seems to be moved back every frame (or so).
So moving the mouse to the right gives X coordinates like
330, 325, 333, 340, 330, ...
and then when stopping movement I get lots of events with X coordinate 320
Olli-Samuli Lehmus
If one creates a window with the SDL_WINDOW_FULLSCREEN_DESKTOP flag, and creates a render target with SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "linear"), and afterwards sets SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "nearest"), after minimizing the window, the scale quality hint is lost on the render target. Textures however do keep their interpolation modes.
Christian Herzig
pthread_mutex_trylock() and by the way, pthread_mutex_lock() do not set errno.
Pthread-methods directly return error code as int. See related man-pages for
details.
Michael Sartain
This is a quick pass at adding Linux RealtimeKit thread priority support to SDL.
It allows me to bump the thread priority to high without root privileges or setting any caps, etc.
rtkit readme here:
http://git.0pointer.net/rtkit.git/tree/README
Simon Hug
I just wanted to fix a simple compiler warning in SDL_ShowMessageBox on Windows (which Sam fixed recently) and ended up finding some issues.
Attached patch fixes these issues:
- Because Windows only reports the lower 16 bits of the control identifier that was pushed, the button IDs used by SDL (C type int, most likely 32 bits) can get cut off.
- The documentation states (somewhat ambiguously) that the button ID will be -1 if the dialog was closed, but the current code sets 0. For SDL 2.1, I think this should be a return code of SDL_ShowMessageBox itself. That will free up the button ID and it seems a more appropriate place for signaling this event.
- Ampersands in controls will create mnemonics on Windows (underlined letters that, if combined with the Alt key, will push the button). I was thinking of adding a hint or flag to let the users enable it, but that might have unexpected results.
- When the size of the text gets calculated, it doesn't use the same parameters as the static control. This can cut off text or wrap it weirdly.
- On Windows, the Tab key is used to switch between control groups and sometimes between buttons in dialogs. This didn't seem to work correctly.
Attached patch also adds:
- Icons. Just the system ones that can be loaded with the ordinals IDI_ERROR, IDI_WARNING and IDI_INFORMATION.
- A button limit of 2^16 - 101.
- Some more specific error messages, but they never reach the user because how SDL_ShowMessageBox handles them if an implementation returns with an error.
This is commented out in SDLActivity.java, with the note #CURSORIMPLEENTATION because it requires API 24, which is higher than the minimum required SDK
Ozkan Sezer
The following patch defines _WIN32_WINNT_WIN7 if it is not already
defined in core/windows/SDL_windows.c, similar to what is already
there for _WIN32_WINNT_VISTA.
Eric Wasylishen
This bug was reintroduced by https://hg.libsdl.org/SDL/rev/fcf24b38a28a
The steps to reproduce are the same: run the "testrelative" SDL demo with "--info all",
connect a USB mouse with a scroll wheel, and roll the scroll wheel one "notch". You'll get log output like:
testdraw2[1644:67222] INFO: SDL EVENT: Mouse: wheel scrolled 0 in x and 0 in y (reversed: 1) in window 1
As far as I can tell macOS doesn't have an API for getting the number of "wheel notches"; I get a deltaY of 0.100006 for one "notch", and it's heavily accelerated (if you roll the wheel quickly you'll get large deltas). So NSEvent's deltaY is only meant to be used for scrolling a scroll view, with the given distance in points, not something like selecting an item in a game.
Here's a temporary patch that at restores the foor/ceil in Cocoa_HandleMouseWheel.
Not ideal, but at least it restores the ability to scroll one notch of a mousewheel.
Ozkan Sezer 2018-03-02 20:02:37 UTC
http://hg.libsdl.org/SDL/rev/d702b0c54e52 resulted in an error and
two warnings when compiled with mingw.
1. Error from SDL_windowstaskdialog.h:
In file included from src/video/windows/SDL_windowsmessagebox.c:29:0:
src/video/windows/SDL_windowstaskdialog.h:23:54: error: expected ')' before 'HWND'
This is fixed by removing unnecessary annotations:
2. Warning from SDL_assert.c:
src/SDL_assert.c: In function 'SDL_ExitProcess':
src/SDL_assert.c:138:1: warning: 'noreturn' function does return
Indeed ExitProcess() is prototyped with DECLSPEC_NORETURN, but
TerminateProcess() is not. This can be rectified by adding an
exit() call in there. Do NOTE, however, that requires building
with a libc:
3. Warning from SDL_windowsmessagebox.c:
src/video/windows/SDL_windowsmessagebox.c: In function 'WIN_ShowMessageBox':
src/video/windows/SDL_windowsmessagebox.c:513:9: warning: 'nCancelButton' may be used uninitialized in this function
My lazy solution was manually initializing nCancelButton to 0.
This lets the message box have an icon. Unless the app has opted-in to using
the v6 common controls, though, this will fall back to the usual SDL message
boxes.
"What I have done is use TerminateProcess rather than ExitProcess.
ExitProcess will cause Microsoft's leak detection to continue, TerminateProcess
won't. It is also technically wrong to use ExitProcess in the case of aborting
the application.
Jack Powell
Twitter @jack9267"
This tries to load vulkan.framework or libvulkan.1.dylib before MoltenVK.framework
or libMoltenVK.dylib. In the previous version, layers would not work for applications
run-time loading the default library.
Manuel Sabogal
If SDL is compiled with the Audio subsystem disabled there are some undefined references to the functions ANDROIDAUDIO_ResumeDevices and ANDROIDAUDIO_PauseDevices in the file src/video/android/SDL_androidevents.c.
With the previous change, I get:
1> Creating library C:\projects\SDL\VisualC\Win32\Debug\SDL2.lib and object C:\projects\SDL\VisualC\Win32\Debug\SDL2.exp
1>LINK : error LNK2001: unresolved external symbol __DllMainCRTStartup@12
Andreas Falkenhahn
In src/SDL.c there is this code:
_DllMainCRTStartup(HANDLE hModule,
...
The comment says that this is needed on Watcom C for some reason but why is it included then when building with Visual C as well? Shouldn't it be only included when compiling on Watcom C then?
I'm asking because this code caused me a lot of headaches because I'm building a DLL that contains SDL and I link using /MT and the _DllMainCRTStartup() symbol obviously led to lots of trouble but it wasn't clear to me where the problem was because all I got from the linker was:
LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup
So I had to got through each and every object to see what the culprit was. See here for the full story:
https://stackoverflow.com/questions/25067151/lnk2019-unresolved-external-symbol-main-referenced-in-function-tmaincrtstar/48177067#48177067
So if it isn't necessary on Visual C, please just leave that symbol out on Visual C so that it no longer leads to any trouble. Thanks.
Most pthread functions return 0 on success and non-zero on error, but those
errors might be positive or negative, so checking for return values in the
Unix style, where errors are less than zero, is a bug.
Fixes Bugzilla #4039.
Callum McGing
This patch allows the user to disable the behaviour that blocks the compositor through a new hint: SDL_VIDEO_X11_NET_WM_BYPASS_COMPOSITOR. This allows tools or other windowed applications to behave properly under KWin.
cjacker
After updating from 2.0.5 to 2.0.7, Ibus not work anymore(fcitx still works).
Compare with 2.0.5, there are two issues in SDL_ibus.c.
1, SetupConnection always return SDL_FALSE in 2.0.7.
2, 'SetCapabilities' method should be called on 'ibus_conn'.
Patch attached.
Alexander Larsson
dbus_shutdown() is a debug feature which closes all global resources in the dbus library. Calling this should be done by the app, not a library, because if there are multiple users of dbus in the process then SDL could shut it down even though another part is using it.
For example, i had an issue with this in mGBA, which uses both Qt and SDL, both using libdbus. I had a session bus, but no system bus (this was in a flatpak sandbox), and when SDL_DBus_Init() failed to init the system bus it called dbus_shudown() and continued on. This caused issues for Qt when running due to its session bus connections having disappeared beneath it.
"*(void**)pfn = LoadAddress()" would cast the NULL pointer in pfn to a
void**, and then dereference it, which wasn't what we wanted. Replaced with
a clearer cast operation.
Viacheslav Slavinsky
SDL_rpivideo driver has 60 frames per second hardcoded in it, this is a problem for games that need to keep pace using VSYNC. I believe that I have found a solution to this. It is based on code in tvservice.c in rpi userland:
a1b89e91f3/host_applications/linux/apps/tvservice/tvservice.c (L433)
ayer.3d
I have a DualShock 4 v2 controller with a GUID that's not in the database. There is an existing GUID that is almost identical, with the only difference that I can tell being the reported version string (mine being 8001, database is 8100).
Existing GUID: 050000004c050000cc09000000810000
New GUID: 050000004c050000cc09000001800000
When connected via USB, the GUID matches an existing entry: 030000004c050000cc09000011810000
This is meant to be the desktop-enhanced version of wl_shell. Right now we
just match what the existing wl_shell code does, but there are other areas of
functionality available to us now, that we can fill in later.
This uses the "unstable" API, since this is what ships in Ubuntu 17.10 (as
part of Wayland 1.10), but Wayland 1.12 promotes this to stable with extremely
minor changes. We will add support for the stable version when it makes sense
to do so.
This variable can be set to the following values:
"0" - The indicator bar is not hidden (default for windowed applications)
"1" - The indicator bar is hidden and is shown when the screen is touched (useful for movie playback applications)
"2" - The indicator bar is dim and the first swipe makes it visible and the second swipe performs the "home" action (default for fullscreen applications)
SDL now builds with gcc 7.2 with the following command line options:
-Wall -pedantic-errors -Wno-deprecated-declarations -Wno-overlength-strings --std=c99
Anthony
This worked in 2.0.5 as normal, but stopped working in 2.0.7. The monitor's resolution doesn't change, a window is created in full screen mode at the virtual desktop resolution instead.
The EGL_GL_COLORSPACE_KHR is an attribute for eglCreate*Surface.
As written in EGL_KHR_gl_colorspace documentation:
Accepted as an attribute name by eglCreateWindowSurface,
eglCreatePbufferSurface and eglCreatePixmapSurface
EGL_GL_COLORSPACE_KHR 0x309D
(...)
A future SDL release will change the borderless window to act more like a normal window that happens to have no chrome, to support windows that draw their own chrome. In the meantime, those applications should set the "SDL_BORDERLESS_WINDOWED_STYLE" hint.
Ismael Ferreras Morezuelas (Swyter)
As a new year gift I have implemented the Windows version of SDL_GetWindowBordersSize(). I needed it for auto-selecting a cozy window size for the game I'm currently working on and noticed that it only worked under X11, so I thought it could be a good excuse to contribute back more stuff. The Mercurial patch is attached as a .diff file. Let me know what you think.
Happy 2018 to all the SDL2 devs and users!
--
PS: Keep in mind that Windows 10 includes the 8px invisible grip borders as part of the frame. There's a way of detecting if Aero/DWM is being used and ask only for the visible rect, but I believe that GetWindowRect() is doing that for a reason and working as intended, so I haven't changed it. (See [2])
References:
[1]: http://www.firststeps.ru/mfc/winapi/r.php?72
[2]: https://stackoverflow.com/a/34143777/674685
[3]: https://stackoverflow.com/a/431548/674685
[4]: https://wiki.libsdl.org/SDL_GetWindowBordersSize
- Use a single buffer for various non-changing constants accessed by the GPU, instead of multiple buffers.
- Do the half-pixel offset for points and lines using a transform matrix so we don't need a malloc when rendering.
- Don't add a half-pixel offset for other primitives and textures. This matches D3D and GL render behaviour.
- Remove the half-texel texture coordinate offset since it's not needed now that there's no more half-pixel position offset when rendering a texture.
- Don't try to set texture usage on iOS 8 since it doesn't exist there.
"GetVersionExA is deprecated in windows 8.1 and above's SDK, causing a warning
when building against the win10 SDK. Attached patch cleans up the usage for a
warning-free build.
GetVersionExA was being used to test to see if SDL was running on win9x or
winnt. A quick chat with Ryan on twitter suggested that SDL doesn't
officially support win9x anymore, so the call to this can be outright removed.
As an aside, replacing the call to GetVersionExA with VerifyVersionInfoA (the
recommended path) would have been pointless, as VerifyVersionInfoA only
supports VER_PLATFORM_WIN32_NT and doesn't officially support any other value
for dwPlatformId currently. (And it's probable that win9x SDKs didn't have
VerifyVersionInfo* in them anyway.)"
Fixes Bugzilla #4019.
Laurent Merckx
I have a problem with the SDL_ShowCursor method on Raspberry.
Depending on the context, my application hides or show the mouse cursor with SDL_ShowCursor.
But when calling SDL_ShowCursor(true), the cursor is displayed at 0,0 (and not at last position).
After debugging sources by myself, it seems that the problem is in SDL_rpimouse.c - RPI_ShowCursor:
vc_dispmanx_rect_set( &dst_rect, 0, 0, curdata->w, curdata->h);
should be
vc_dispmanx_rect_set( &dst_rect, mouse->x, mouse->y, curdata->w, curdata->h);
For me, it solves the problem.
tomwardio
HAVE_POLL is correctly defined in SDL_config.h when running configure. However, in the only place where it's used, it's undefined at the start of the file.
Dominik Reichardt
As discussed in 2012 the iOS onscreen keyboard hides when you hit RETURN (see https://discourse.libsdl.org/t/on-screen-keyboard-change/19216).
IMO this is a bad idea to not be able to influence this behavior and just recently this was fixed for Android by adding the hint SDL_HINT_ANDROID_RETURN_HIDES_IME in changeset 11768 6ce3bb5e38a5.
Eric wing
There is a tiny bug in the new overscan code for the SDL_renderer.
In SDL_renderer.c, line 1265, the if check for SDL_strcasecmp with "direct3d" needs to be inverted.
Instead of:
if(SDL_strcasecmp("direct3d", SDL_GetCurrentVideoDriver())) {
It should be:
if(0 == SDL_strcasecmp("direct3d", SDL_GetCurrentVideoDriver())) {
This bug causes the "overscan" mode to pretty much be completely ignored in all cases and all things remain letterboxed (as before the feature).
Elis?e Maurer
The attached minimal program sets the SDL_HINT_MOUSE_RELATIVE_MODE_WARP to 1, enables relative mouse mode then logs all SDL_MOUSEMOTION xrel values as they happen.
When moving the mouse exclusively to the right:
* On a Windows 10 installation before Fall Creators update (for instance, Version 10.0.15063 Build 15063), only positive values are reported, as expected
* On a Windows 10 installation after Fall Creators update (for instance, Version 10.0.16299 Update 16299), a mix of positive and negative values are reported.
3 different people have reproduced this bug and have confirmed it started to happen after the Fall Creators update was installed. It happens with SDL 2.0.7 as well as latest default branch as of today.
It seems like some obscure (maybe unintended) Windows behavior change? Haven't been able to pin it down more yet.
(To force-upgrade a Windows installation to the Fall Creators update, you can use the update assistant at https://www.microsoft.com/en-us/software-download/windows10)
Eric Wasylishen
Broken GetCursorPos / SetCursorPos based games on Win 10 fall creators are not limited to SDL.. I just tested winquake.exe (original 1997 exe) and it now has "jumps" in the mouse input if you try to look around in a circle. It uses GetCursorPos/SetCursorPos by default. Switching WinQuake to use directinput (-dinput flag) seems to get rid of the jumps.
Daniel Gibson
A friend tested on Win10 1607 (which is before the Fall Creators Update) and the the bug doesn't occur there, so the regression that SetCursorPos() doesn't reliably generate mouse events was indeed introduced with that update.
I even reproduced it in a minimal WinAPI-only application (https://gist.github.com/DanielGibson/b5b033c67b9137f0280af9fc53352c68), the weird thing is that if you don't do anything each "frame" (i.e. the mainloop only polls the events and does nothing else), there are a lot of mouse events with the coordinates you passed to SetCursorPos(), but when sleeping for 10ms in each iteration of the mainloop, those events basically don't happen anymore. Which is bad, because in games the each iteration of the mainloop usually takes 16ms..
I have a patch now that I find acceptable.
It checks for the windows version with RtlGetVersion() (https://msdn.microsoft.com/en-us/library/windows/hardware/ff561910.aspx) and only if it's >= Win10 build 16299, enables the workaround.
All code is in video/windows/SDL_windowsevents.c
and the workaround is, that for each WM_MOUSEMOVE event, "if(isWin10FCUorNewer && mouseID != SDL_TOUCH_MOUSEID && mouse->relative_mode_warp)", an addition mouse move event is generated with the coordinates of the center of the screen
(SDL_SendMouseMotion(data->window, mouseID, 0, center_x, center_y);) - which is exactly what would happen if windows generated those reliably itself.
This will cause SDL_PrivateSendMouseMotion() to set mouse->last_x = center_x; and mouse->last_y = center_y; so the next mouse relative mouse event will be calculated correctly.
If Microsoft ever fixes this bug, the IsWin10FCUorNewer() function would have to
be adjusted to also check for a maximum version, so the workaround is then disabled again.
Ethan Lee
Sam Lantinga
Alex Szpakowski
Ryan C. Gordon
Ozkan Sezer
Anthony Pesch
Tomeu Vizoso
Mark Callow
Ozkan Sezer
Brandon Schaefer
Guillermo A. Amaral
Dawid Gan
John Bartholomew
Marius Gripsgard