Anthony Pesch
I was looking into my own input bug and noticed an issue in the HIDAPI code while looking over it. I don't have a controller that goes down this path to test and try to provoke the issue, but it looks pretty straight forward.
The memmove to shift the joystick id array on disconnect isn't scaling the size by sizeof(SDL_JoystickID), likely corrupting the ids on disconnect.
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.
* 8BitDo N30 Pro 2
* 8BitDo SN30 Gamepad
* 8BitDo SN30 Pro+
* 8BitDo Zero 2
* SZMY-POWER PC Gamepad
* ThrustMaster eSwap PRO Controller
* ZEROPLUS P4 Wired Gamepad
In additional, all 8BitDo controllers use SDL_HINT_GAMECONTROLLER_USE_BUTTON_LABELS to have the correct mapping based on user preferences.
The joystick layer can't necessarily give us perfect centering, but we know
that the game controller level has logical absolute idle positions that have
nothing to do with the physical device.
So send game controller events to make it look like the device is completely
untouched before sending the final removal event.
This driver supports the Razer Atrox Arcade Stick
Some of the quirks of this driver, inherent in Windows Gaming Input:
* There will never appear to be controllers connected at startup. You must support hot-plugging in order to see these controllers.
* You can't read the state of the guide button
* You can't get controller events in the background
meyraud705
On line 220 of SDL_hidapi_xbox360.c https://hg.libsdl.org/SDL/file/4608f0e6e8e3/src/joystick/hidapi/SDL_hidapi_xbox360.c#l220
if (!XINPUTGETSTATE(user_index, &xinput_state[user_index].state) == ERROR_SUCCESS) {
logical not is only applied to the left hand side of this comparison.
I think you mean:
if (XINPUTGETSTATE(user_index, &xinput_state[user_index].state) != ERROR_SUCCESS) {
bluenaxela+sdl
I've noticed that the Switch Pro Controller hidapi driver does not report battery levels when connected via Bluetooth, despite having code for setting joystick->epowerlevel.
This is caused by the driver always using k_eSwitchInputReportIDs_SimpleControllerState via Bluetooth. Using that mode means that the state reports you get back from the controller do not include battery state. Not using the full controller state over Bluetooth effectively makes this driver's support for setting joystick->epowerlevel entirely pointless, only ever reporting SDL_JOYSTICK_POWER_WIRED.
Is there a reason this was set to only use SimpleControllerState via Bluetooth?
I've attached a patch I'm using to allow getting battery level for the Switch Pro Controller.
A couple notes about this patch:
1) It changes LoadStickCalibration to accept the input_mode that is selected, because that's really what should determine what is used for stick extents, since stick extents differ between the modes.
2) In my patch I only use FullControllerState when the vid/pid matches the official Switch Pro Controller, as a cautionary measure in case some third-party controllers have problems with FullControllerState mode via Bluetooth (I noticed a HORI Wireless Switch Pad I had seemed to not read controller calibration correctly for stick extents. Maybe it's calibration data was uninitialized on account of having never been used with a Switch? I'm unsure, though if that guess is right maybe SDL2 should be detecting an uninitiated calibration state and using some sensible defaults)
bluenaxela+sdl
The HORI Wireless Switch Pad does not properly connect via bluetooth. I did some debugging and found that the code that tries to control the Home LED causes this controller to disconnect.
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.
Jimb Esser
Add new RawInput controller API, and improved correlation with XInput/WGI
Reorder joystick init so drivers can ask the others if they handle a device reliably
Do not poll disconnected XInput devices (major perf issue)
Fix various cases where incorrect correlation could happen
Simple mechanism for propagating unhandled Guide button presses even before guaranteed correlation
Correlate by axis motion as well as button presses
Fix failing to zero other trigger
Fix SDL_HINT_JOYSTICK_HIDAPI not working if set before calling SDL_Init()
Add missing device to device names
Disable RawInput if we have a mismatch of XInput-capable but not RawInput-capable devices
Updated to SDL 2.0.13 code with the following notes:
New HID driver: xbox360w - no idea what that is, hopefully urelated
SDL_hidapijoystick.c had been refactored to couple data handling logic with device opening logic and device lists caused some problems, yields slightly uglier integration than previously when the 360 HID device driver was just handling the data.
SDL_hidapijoystick.c now often pulls the device off of the joystick_hwdata structure for some rumble logic, but it appears that code path is never reached, so probably not a problem.
Looks like joystick_hwdata was refactored to not include a mutex in other drivers, maintainers may want to do the same refactor here if that's useful for some reason.
Something changed in how devices get names, so getting generic names.
Had to fix a (new?) bug where removing an XInput controller caused existing controllers (that moved to a new XInput index) to get identified as 0x045e/0x02fd ("it's probably Bluetooth" in code), rendering the existing HIDAPI_IsDevicePresent and new RAWINPUT_IsDevicePresent unreliable.
Jimb Esser
Add new RawInput controller API, and improved correlation with XInput/WGI
Reorder joystick init so drivers can ask the others if they handle a device reliably
Do not poll disconnected XInput devices (major perf issue)
Fix various cases where incorrect correlation could happen
Simple mechanism for propagating unhandled Guide button presses even before guaranteed correlation
Correlate by axis motion as well as button presses
Fix failing to zero other trigger
Fix SDL_HINT_JOYSTICK_HIDAPI not working if set before calling SDL_Init()
Add missing device to device names
Disable RawInput if we have a mismatch of XInput-capable but not RawInput-capable devices
Updated to SDL 2.0.13 code with the following notes:
New HID driver: xbox360w - no idea what that is, hopefully urelated
SDL_hidapijoystick.c had been refactored to couple data handling logic with device opening logic and device lists caused some problems, yields slightly uglier integration than previously when the 360 HID device driver was just handling the data.
SDL_hidapijoystick.c now often pulls the device off of the joystick_hwdata structure for some rumble logic, but it appears that code path is never reached, so probably not a problem.
Looks like joystick_hwdata was refactored to not include a mutex in other drivers, maintainers may want to do the same refactor here if that's useful for some reason.
Something changed in how devices get names, so getting generic names.
Had to fix a (new?) bug where removing an XInput controller caused existing controllers (that moved to a new XInput index) to get identified as 0x045e/0x02fd ("it's probably Bluetooth" in code), rendering the existing HIDAPI_IsDevicePresent and new RAWINPUT_IsDevicePresent unreliable.
Malte Kie?ling
I get a build error in SDL_sysjoystick.c:74 for the merged patch, but its nothing to sweat about, just -Werror=declaration-after-statement doing its usual stuff.
David Ludwig
I have created a new driver for SDL's Joystick and Game-Controller subsystem: a Virtual driver. This driver allows one to create a software-based joystick, which to SDL applications will look and react like a real joystick, but whose state can be set programmatically. A primary use case for this is to help enable developers to add touch-screen joysticks to their apps.
The driver comes with a set of new, public APIs, with functions to attach and detach joysticks, set virtual-joystick state, and to determine if a joystick is a virtual-one.
Use of virtual joysticks goes as such:
1. Attach one or more virtual joysticks by calling SDL_JoystickAttachVirtual. If successful, this returns the virtual-device's joystick-index.
2. Open the virtual joysticks (using indicies returned by SDL_JoystickAttachVirtual).
3. Call any of the SDL_JoystickSetVirtual* functions when joystick-state changes. Please note that virtual-joystick state will only get applied on the next call to SDL_JoystickUpdate, or when pumping or polling for SDL events (via SDL_PumpEvents or SDL_PollEvent).
Here is a listing of the new, public APIs, at present and subject to change:
------------------------------------------------------------
/**
* Attaches a new virtual joystick.
* Returns the joystick's device index, or -1 if an error occurred.
*/
extern DECLSPEC int SDLCALL SDL_JoystickAttachVirtual(SDL_JoystickType type, int naxes, int nballs, int nbuttons, int nhats);
/**
* Detaches a virtual joystick
* Returns 0 on success, or -1 if an error occurred.
*/
extern DECLSPEC int SDLCALL SDL_JoystickDetachVirtual(int device_index);
/**
* Indicates whether or not a virtual-joystick is at a given device index.
*/
extern DECLSPEC SDL_bool SDLCALL SDL_JoystickIsVirtual(int device_index);
/**
* Set values on an opened, virtual-joystick's controls.
* Returns 0 on success, -1 on error.
*/
extern DECLSPEC int SDLCALL SDL_JoystickSetVirtualAxis(SDL_Joystick * joystick, int axis, Sint16 value);
extern DECLSPEC int SDLCALL SDL_JoystickSetVirtualBall(SDL_Joystick * joystick, int ball, Sint16 xrel, Sint16 yrel);
extern DECLSPEC int SDLCALL SDL_JoystickSetVirtualButton(SDL_Joystick * joystick, int button, Uint8 value);
extern DECLSPEC int SDLCALL SDL_JoystickSetVirtualHat(SDL_Joystick * joystick, int hat, Uint8 value);
------------------------------------------------------------
Miscellaneous notes on the initial patch, which are also subject to change:
1. no test code is present in SDL, yet. This should, perhaps, change. Initial development was done with an ImGui-based app, which potentially is too thick for use in SDL-official. If tests are to be added, what kind of tests? Automated? Graphical?
2. virtual game controllers can be created by calling SDL_JoystickAttachVirtual with a joystick-type of SDL_JOYSTICK_TYPE_GAME_CONTROLLER, with naxes (num axes) set to SDL_CONTROLLER_AXIS_MAX, and with nbuttons (num buttons) set to SDL_CONTROLLER_BUTTON_MAX. When updating their state, values of type SDL_GameControllerAxis or SDL_GameControllerButton can be casted to an int and used for the control-index (in calls to SDL_JoystickSetVirtual* functions).
3. virtual joysticks' guids are mostly all-zeros with the exception of the last two bytes, the first of which is a 'v', to indicate that the guid is a virtual one, and the second of which is a SDL_JoystickType that has been converted into a Uint8.
4. virtual joysticks are ONLY turned into virtual game-controllers if and when their joystick-type is set to SDL_JOYSTICK_TYPE_GAMECONTROLLER. This is controlled by having SDL's default list of game-controllers have a single entry for a virtual game controller (of guid, "00000000000000000000000000007601", which is subject to the guid-encoding described above).
5. regarding having to call SDL_JoystickUpdate, either directly or indirectly via SDL_PumpEvents or SDL_PollEvents, before new virtual-joystick state becomes active (as specified via SDL_JoystickSetVirtual* function-calls), this was done to match behavior found in SDL's other joystick drivers, almost all of which will only update SDL-state during SDL_JoystickUpdate.
6. the initial patch is based off of SDL 2.0.12
7. the virtual joystick subsystem is disabled by default. It should be possible to enable it by building with SDL_JOYSTICK_VIRTUAL=1
Questions, comments, suggestions, or bug reports very welcome!
Ethan Lee
Basically replicating the solution of the Switch Controller's button label issue. Physical layout should take priority unless it's explicitly requested by the user or application!
Prior to this fix, we would hit the existing_instance >= 0 case and move the joystick
again to a different index than the one requested by the caller. It also breaks the assumption
that a SDL_JoystickID is only present in SDL_joystick_players at one location.
Sam Lantinga
Kai Krakow
stfx
Ryan C. Gordon
Cameron Gutman
Brendan Shanks
Jimb Esser
David Ludwig