Since the haptic subsystem is usually initialized after the joystick subsystem,
the initial calls to HapticMaybeAddDevice() from inside SDL_JoystickInit() will
arrive too early to be handled by the haptic subsystem. We need to add those
haptic devices for those already present joysticks ourselves.
The joystick subsystem has complex precedence logic to deal multiple competing
backends like XInput, RawInput, and WGI. Let it fire the MaybeAdd callbacks
for joystick devices, since it knows which backend will end up managing them.
This resolves a situation where the RawInput joystick backend would take
control of an XInput device but the XInput haptic backend would still create
a haptic device. Since the XInput joystick backend didn't own the underlying
joystick device, we'd end up with an orphaned haptic device that didn't work
with SDL_HapticOpenFromJoystick() on the associated joystick device.
- Do not call IDirectInputDevice8_QueryInterface(device, &IID_IDirectInputDevice8,...) on DIRECTINPUTDEVICE8 device
- Get joystick VendorID and ProductID via IDirectInputDevice8_GetProperty(.., DIPROP_VIDPID, ..) call instead of messing with DIDEVICEINSTANCE.guidProduct
- Normalize HID device interface path to upper case for stable operation of XInput check
- Remove useless RawInput calls in SDL_IsXInputDevice() - just check for "IG_" string in HID device interface path that we already have
There shouldn't be any observable behavior changes.
meyraud705
I see how the documentation is confusing. I think that the choice of the axis is an implementation detail. The documentation should state the goal of this value, so I propose this wording:
"Use this value to play an effect on the steering wheel axis. This provides
better compatibility across platforms and devices as SDL will guess the
correct axis."
Value could even be renamed 'SDL_HAPTIC_STEERING_AXIS'.
For Linux, sending an effect on the X axis with a Logitech wheel works. Others brands don't have driver for Linux as far as I know.
Mathieu Laurendeau
Consider a device supporting effects on multiple axes.
There's currently no way to play effects against a single-axis direction.
A device supporting effects against X and Y may not allow to play effects with a two-axis direction coordinate, even if one of the coordinates is null.
My current (ugly) work around for this is to add a direction type SDL_HAPTIC_X_FORCE to play effects against a X-axis only direction (patch attached).
This issue impacted two GIMX users using the following wheels:
- Leo Bodnar SimSteering force feedback wheel
- Accuforce direct drive wheel
Playing constant/spring/damper effects against a X-axis direction worked well for the first wheel, but not for the second one.
A better strategy seems to play the effects against the first axis reported by the DirectInput enumeration.
This strategy also works with Logitech wheels (at least the DFGT).
It's been more than a year that I have the latest patch (playing effects against the first axis only) in the GIMX software. It's being used by thousands of people, mostly for adapting their FFB wheel to the PS4. I had no report that proves this strategy to be wrong.
Joe Thompson
With Direct Input device (MOMO Steering Wheel w/FF)
with SDL 2.0.3,
SDL_HapticOpenFromJoystick() would fail. (Can't set exclusive mode)
Now with 2.0.4 rc1,
SDL_HapticOpenFromJoystick() succeeds but the the returned SDL_Haptic* cannot be used. Calls to SDL_HapticNewEffect() fail with "Haptic error Unable to create effect"
If SDL_HapticOpen() is used instead of HapticOpenFromJoystick(), the device is usable. Calls to HapticNewEffect() succeed with the exact same parameters as the previous failing call.
I have attached a proposed patch for this issue.
When using SDL_HapticOpenFromJoystick(), the original code did not (re)enumerate the axes. This returned a new haptic device with 0 axes. Later, when a new effect is created, SDL_SYS_SetDirection() would set the flags to include DIEFF_SPHERICAL, regardless of what the caller actually set. (see Line 566 in SDL_dinputhaptic.c). This would cause the SDL_HapticNewEffect() to fail (or interpret the coordinates incorreclty.)
The patch moves the call to IDirectInputDevice8_EnumObjects() outside of the if() block so that the axes are (re)enumerated for the new haptic device.
Note: For steering wheels it is common for the joystick to have multiple axes (ie steering, throttle, brake), but the haptic portion of the joystick usually only applies to steering.
This allows us to set an explicit stack size (overriding the system default
and the global hint an app might have set), and remove all the macro salsa
for dealing with _beginthreadex and such, as internal threads always set those
to NULL anyhow.
I've taken some guesses on reasonable (and tiny!) stack sizes for our
internal threads, but some of these might turn out to be too small in
practice and need an increase. Most of them are simple functions, though.
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().
pionere
Sam Lantinga
Cameron Gutman
Dimitriy Ryazantcev
stfx
Ryan C. Gordon
Philipp Wiesemann