pj5085
I added some printf to verify the math being done. Of the three joysticks I have, it works correctly for at least two, and seems to work correctly for the third. I say "seems to" because, for the third joystick, the values never go through the AxisCorrect function, and thus never hit my printf statements, even though they did in the version I wrote my patch against. I'm not sure what's going on there, but it at least seems to be working correctly in as much as I can tell.
I note this result in particular, for an SNES Gamepad (min=0, max=255):
Joystick value 0 becomes -32768
Joystick value 127 becomes 0
Joystick value 255 becomes 32767
Without the code that forces a zero point, the 127 input value would become -129, so I think you see why I added that code to turn it into zero. However, I think Kai Krakow has a point about how SDL shouldn't assume that there should be a center.
Obviously in the majority of cases there actually should be a center, and the code that turns that 127 into an actual 0 is creating only a 0.2% error over 0.4% of this joystick's range. However, what if there is an axis that is some kind of special control, like a 4-position switch, and, for whatever reason, the joystick reports it as an axis with 4 possible values, 0 to 3? In that case, mutilating the two center values to the same value is much more of an error and and turns that 4-position switch into a 3-position switch. If any joystick does this with a 2-position switch, then this code would render that control entirely useless as it would report the same value with the switch in either position. Obviously the code could require that there be at least N possible values, to guess whether something is a proper axis or just some kind of switch, but the choice of N would be arbitrary and that's ugly.
I guess the real problem here is that my gamepad is just kind of broken. It should be reporting a range of -1 to +1 since that's what it actually does. Also, as Kai Krakow points out, it's probably not SDL's place to fix broken hardware. I'll add that, if SDL does fix broken hardware, it should probably actually know that it's broken rather than be merely guessing that it is.
So, to the extent that SDL is able to do stuff like this, perhaps it's something better left for the user to configure in some kind of config file.
configure output is practically unchanged. there are still lots of
AC_TRY_COMPILE/AC_TRY_LINK replacements needed to really eliminate
the warnings, but that's for another time.
pj5085
It occurred to me that my simple patch that comments out a few lines of code does not correctly remove the dead zone since the calculation presumably assumes the dead zone has been cut out of the range. Then, while looking into how to make it output the correct range of values, I realized SDL wasn't returning the correct range of values to begin with.
This line of code was already present:
printf("Values = { %d, %d, %d, %d, %d }\n", absinfo.value, absinfo.minimum, absinfo.maximum, absinfo.fuzz, absinfo.flat);
For my joystick this yeilds:
Values = { 0, -127, 127, 0, 15 }
Then this code calculates the coefficients:
In SDL1:
joystick->hwdata->abs_correct[i].coef[0] = (absinfo.maximum + absinfo.minimum) / 2 - absinfo.flat;
joystick->hwdata->abs_correct[i].coef[1] = (absinfo.maximum + absinfo.minimum) / 2 + absinfo.flat;
t = ((absinfo.maximum - absinfo.minimum) / 2 - 2 * absinfo.flat);
if ( t != 0 ) {
joystick->hwdata->abs_correct[i].coef[2] = (1 << 29) / t;
} else {
joystick->hwdata->abs_correct[i].coef[2] = 0;
}
In SDL2:
joystick->hwdata->abs_correct[i].coef[0] = (absinfo.maximum + absinfo.minimum) - 2 * absinfo.flat;
joystick->hwdata->abs_correct[i].coef[1] = (absinfo.maximum + absinfo.minimum) + 2 * absinfo.flat;
t = ((absinfo.maximum - absinfo.minimum) - 4 * absinfo.flat);
if (t != 0) {
joystick->hwdata->abs_correct[i].coef[2] = (1 << 28) / t;
} else {
joystick->hwdata->abs_correct[i].coef[2] = 0;
}
Neither calculates the correct coefficients for the code in the AxisCorrect function.
In SDL1:
if ( value > correct->coef[0] ) {
if ( value < correct->coef[1] ) {
return 0;
}
value -= correct->coef[1];
} else {
value -= correct->coef[0];
}
value *= correct->coef[2];
value >>= 14;
In SDL2:
value *= 2;
if (value > correct->coef[0]) {
if (value < correct->coef[1]) {
return 0;
}
value -= correct->coef[1];
} else {
value -= correct->coef[0];
}
In SDL1, the calculated coefficients are coef[0]=15, coef[1]=-15 and coef[2]=5534751. So with a full-scale input of 127, it calculates an output value of 37835, which is considerably out of range.
In SDL2, the calculated coefficients are coef[0]=30, coef[1]=-30, and coef[2]=1383687. So with a full-scale input of 127, it calculates the same output value of 37835.
I tested it with the 3 joysticks I have, and it produces out-of-range values for all of them.
Anyway, since dead zones are garbage, I just deleted all of that junk and wrote some code that takes the absinfo.minimum and absinfo.maximum values and uses them to scale the axis range to -32767 through +32767.
I also made it detect when a range doesn't have an integer center point, e.g. the center of -128 to + 127 is -0.5. In such cases, if either value to the side of the center is provided, it zeros it, but it otherwise doesn't implement any kind of dead zone. This seemed important with my gamepad which provides only the values of 0, 127, and 255, since without this hack it would never be centered.
Also, the previous minimum output value was -32768, but as that creates an output range that has no true center, I changed the minimum value to -32767.
I tested it with the 3 joystick devices I have and it seems to create correct values for all of them.
Added a hint to control whether a separate thread should be used for joystick events.
This is off by default because dispatching messages in other threads appears to cause problems on some versions of Windows.
- SDL_video.c (SDL_ShowMessageBox): replace messageboxdata, set title
or message field to "" if either of them is NULL.
- SDL_video.c (SDL_ShowSimpleMessageBox): set title or message to ""
if either of them is NULL for EMSCRIPTEN builds.
- SDL_bmessagebox.cc: add empty string check along with NULL check for
title and message fields.
- SDL_windowsmessagebox.c (AddDialogString): remove NULL string check
- SDL_windowsmessagebox.c (AddDialogControl): add empty string check
along with the NULL check.
- SDL_x11messagebox.c: revert commit 677c4cd68069
- SDL_os2messagebox.c: revert commit 2c2a489d76e7
- test/testmessage.c: Add NULL title and NULL message tests.
Joel Linn
TLDR; https://godbolt.org/z/43fd8G
Let's deduce this from C++ reference code:
https://docs.microsoft.com/en-us/cpp/cppcx/wrl/how-to-activate-and-use-a-windows-runtime-component-using-wrl?view=msvc-160
At the bottom of the page there is this snippet:
```
int wmain()
{
/* ... more code ... */
// Get the domain part of the URI.
HString domainName;
hr = uri->get_Domain(domainName.GetAddressOf());
if (FAILED(hr))
{
return PrintError(__LINE__, hr);
}
// Print the domain name and return.
wprintf_s(L"Domain name: %s\n", domainName.GetRawBuffer(nullptr));
// All smart pointers and RAII objects go out of scope here.
}
```
`HString` is defined in `corewrappers.h` and the call chain for the destructor is:
`~HString() -> Release() -> ::WindowsDeleteString()`
QED
Sven-Hendrik Haase
In CMake I currently have trouble activating hidapi support as libusb-1.0 isn't ever correctly detected as it's searched for by the wrong name.
configure.ac correctly does this:
PKG_CHECK_MODULES([LIBUSB], [libusb-1.0], have_libusb=yes, have_libusb=no)
However, sdlchecks.cmake does this:
pkg_check_modules(LIBUSB libusb)
but it needs to be:
pkg_check_modules(LIBUSB libusb-1.0)
Vincent Hamm
Xcode11 and ios13 added support for metal simulator.
Here is a quick and dirty patch to enable it. Pretty early and only tested on a few samples for now. Required mostly to enable metal support on correct version of ios, generate simulator compatible shaders and enforce buffer alignments on simulator (same as osx).
Sebastian Vargas Vargas
Running CMake configure from a Windows Subsystem for Linux using Visual Studio Code Remote doesn't generate the header file with the current source revision, it throws "/home/sebva/SDL/build-scripts/updaterev.sh: 13: cannot create /mnt/c/Users/sebva/.vscode/extensions/ms-vscode-remote.remote-wsl-0.44.4/include/SDL_revision.h.new: Directory nonexistent".
If we fail to connect to the the pa server, we have an assigned context
and mainloop that isn't connected. So, when PULSEAUDIO_pa_context_disconnect
is called, pa asserts and crashes the application.
Assertion 'pa_atomic_load(&(c)->_ref) >= 1' failed at pulse/context.c:1055, function pa_context_disconnect(). Aborting.
Joel Linn
Eliminate additional heap allocation for short-lived HSTRINGs.
Uses `WindowsCreateStringReference()` to disable reference counting and memory management by the Window Runtime.
Tom Seddon
2nd time lucky, perhaps. patch 2 applies to current HEAD at time of writing - 4eb049c9bb1ca94efe3c40b57beda3169984d0cb from https://github.com/SDL-mirror/SDL.
This basically goes back to what was there originally, but now manually adding "-x objective-c" to the clang command line rather than "-ObjC". clang is then invoked without the "-x c" that was causing the problem, the snippet builds, and Metal is detected. (I had a quick trawl through the cmake code, but I couldn't see where this is handled.)
I was moved to try this after finding SDL's own CHECK_OBJC_SOURCE_COMPILES macro, and noting what it does: 4eb049c9bb/cmake/macros.cmake (L67)
An alternative fix of course would be to use CHECK_OBJC_SOURCE_COMPILES instead of cmake's check_objc_source_compiles - but that had the same problem of getting confused by "return 0;". (Maybe that's because it's a macro? I'll defer to a cmake expert on this one.)
I decided in the end to err on the side of leaving things looking basically the same as they were before my first patch.
Ivan Mogilko
With SDL 2.0.12 under MS Windows, if the window is partially offscreen calling SDL_SetWindowGrab(w, SDL_TRUE) works, but subsequent call to SDL_SetWindowGrab(w, SDL_FALSE) does not work.
I tested this in both real program, and a small test app, where unlocking cursor worked perfectly while window is fully in desktop bounds, but did not work if it was at least few pixels outside.
For the reference, following code is enough to reproduce the issue:
#include <windows.h>
#include <SDL.h>
int WinMain(
HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nShowCmd)
{
SDL_Init(SDL_INIT_VIDEO);
SDL_Window* w = SDL_CreateWindow("", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 400, 0);
bool grabbed = false;
bool want_quit = false;
while (!want_quit)
{
SDL_Event event;
while (SDL_PollEvent(&event))
{
switch (event.type)
{
case SDL_QUIT: want_quit = true; break;
case SDL_KEYDOWN:
if (event.key.keysym.scancode == SDL_SCANCODE_SPACE)
{
SDL_SetWindowGrab(w, static_cast<SDL_bool>(!grabbed));
grabbed = !grabbed;
}
}
}
}
SDL_DestroyWindow(w);
SDL_Quit();
return 0;
}
Mathieu Eyraud
SDL dynamically loads libusb but does not check the return value of 'SDL_LoadFunction'.
Also libusb is loaded and initialized several time because 'SDL_hidapi_wasinit' is never set to true.
I made a patch if you want to test:
- check that 'hid_init' is called once and only once,
- check return value of 'hid_init',
- check return value of 'SDL_LoadFunction',
- check return value of 'SDL_malloc',
- add some debug logging.
Sam Lantinga
Ozkan Sezer
Alistair Leslie-Hughes
Alice Rowan
Mikhail Paulyshka