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.
This is a multi-part fix, and is the 2nd attempt at a fix for Bug 5034. Here
are the problems being addressed:
1. On macOS 10.14.x and earlier, trying to call IOHIDDeviceUnscheduleFromRunLoop
without a prior, paired call to IOHIDDeviceScheduleWithRunLoop, appears to
lead to a crash. A per-device flag has been added to make sure that these
calls are paired.
2. DARWIN_JoystickDetect was free'ing its SDL_joystick's hwdata field
(via FreeDevice) without setting it to NULL, and DARWIN_JoystickRumble wasn't
checking for a NULL hwdata. FreeDevice will now set hwdata to NULL and
DARWIN_JoystickRumble will check for a NULL hwdata.
This fixes a crash whereby SDL could crash on macOS/Darwin, if and when a
USB game controller gets unplugged. SDL was not retaining a reference
to the controller's OS/IOKit-provided 'device object', and was capable
of trying to use it, after a device was hot-unplugged.
Added the functions SDL_JoystickFromPlayerIndex(), SDL_JoystickSetPlayerIndex(), SDL_GameControllerFromPlayerIndex(), and SDL_GameControllerSetPlayerIndex()
The code is now reliant on SDL_PrivateJoystickAdded() and SDL_PrivateJoystickRemoved() being called correctly when devices are added or removed on Windows
Firmware revision 3.1.1221.0 changes the mapping of the Xbox One S
controller in Bluetooth mode. Aside from changing the layout of
other buttons, this revision also changes the triggers to act as
Accelerator and Brake axes from the simulation controls page.
The Darwin sysjoystick code didn't previously map anything at these
axes, making it impossible to detect input on these two buttons.
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.
I don't know if any joysticks report those usages for any buttons in practice, but other prominent Mac gaming software exposes them, so we might as well too.
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().
Ethan Lee
Sam Lantinga
Ryan C. Gordon
David Ludwig
Misty De Meo
Philipp Wiesemann
Alex Szpakowski