Jan Bujak
I wrote a new driver for my gamepad on Linux. I'd like SDL to support it out-of-box, as currently it just treats it as a generic joystick instead of a gamepad. From what I can see the only way to do that is to either 1) pick one of the already supported controllers' PID, VID and button layouts and have my driver send that (effectively lying that it's something else), or 2) submit a preconfigured, hardcoded mapping to SDL.
Both of those, in my opinion, are silly when we already have the Linux Gamepad Specification which standarizes this:
https://www.kernel.org/doc/html/v4.15/input/gamepad.html
Unfortunately SDL doesn't make use of it currently. So I've took it upon myself to add it; patch is in the attachments.
Basically what the patch does is that if SDL finds no built-it controller mappings for a given joystick it then asks the joystick backend to autodetect it, and that uses the relevant evdev bits to figure out which button/axis is which. (See the specs for more details.)
With this patch applied my own driver for my controller works out-of-box with SDL with no extra configuration and is correctly recognized as a gamepad; this is also going to be the case for any other driver which follows the Linux Gamepad Specification.
Added the functions SDL_JoystickFromPlayerIndex(), SDL_JoystickSetPlayerIndex(), SDL_GameControllerFromPlayerIndex(), and SDL_GameControllerSetPlayerIndex()
daniel.c.sinclair
Hi, this patch breaks dpad/hat input on my PS4 controller. The attached patch restores functionality. Calling SDL_PrivateJoystickHat() at the end of BSD_JoystickUpdate was setting the hat state to zero on every kind of input, instead of just the HUG_DPAD events.
Thomas Frohwein
Hi,
If a gamepad lists the Dpad as 4 buttons (Dpad Up,Down, Left, Right) like with the Xbox 360 gamepad / XInput report descriptor used by OpenBSD (https://github.com/openbsd/src/blob/master/sys/dev/usb/uhid_rdesc.h#L184), this is not recognized by the SDL BSD backend and no hat or any other listing for the D-pad exists, e.g. in sdl2-jstest (https://gitlab.com/sdl-jstest/sdl-jstest).
The attached diff fixes this and makes the D-pad on my Xbox 360 and Logitech F310 controllers usable. It adds a hat to nhats when usage HUG_DPAD_UP is found, reads the state of the D-pad buttons into array dpad[], and turns the value of dpad[] into an SDL hat direction (dpad_to_sdl()).
Tested and works with Xbox 360 controller and Logitech F310 in XInput mode. Software-side tested with sdl2-jstest and Owlboy where this worked without problems or regressions.
I don't know if this would be applicable to other *BSDs and don't have an install to test it with, therefore wrapped it in __OpenBSD__ ifdefs.
Thanks,
thfr
src/vendor/SDL2/src/joystick/bsd/SDL_sysjoystick.c:353:5: error:
ISO C90 forbids mixed declarations and code [-Werror=declaration-after-statement]
reported by 'bch' at https://discourse.libsdl.org/t/25231
The code is now reliant on SDL_PrivateJoystickAdded() and SDL_PrivateJoystickRemoved() being called correctly when devices are added or removed on Windows
Fixed a case where partial trigger pull could be bound to another button
There is a fundamental problem not resolved by this commit:
Some controllers have axes (triggers, pedals, etc.) that don't start at zero, but we're guaranteed that if we get a value that it's correct. For these controllers, the current code works, where we take the first value we get and use that as the zero point and generate axis motion starting from that point on.
Other controllers have digital axes (D-pad) that assume a zero starting point, and the first value we get is the min or max axis value when the D-pad is moved. For these controllers, the current code thinks that the zero point is the axis value after the D-pad motion and this doesn't work.
My hypothesis is that the first class of devices is more common and that we should solve for that, and add an exception to SDL_JoystickAxesCenteredAtZero() as needed for the second class of devices.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
