Unable to set HapticDirection.dir

[theGeekPirate]

dir is unexported (https://github.com/veandco/go-sdl2/blob/master/sdl/haptic.go#L46) and has no methods to set it with, so we're currently unable to use it.

https://wiki.libsdl.org/SDL_HapticDirection

[malashin]

Hey @theGeekPirate, Dir is exported now. Thank you for your feedback.

I am wondering if anyone has actually used the bindings for haptics. Either I am missing something or there is no way to actually create/update the HapticEffect. I had to update the C pointer for this to work:

err := sdl.Init(sdl.INIT_EVERYTHING)
if err != nil {
	panic(err)
}

joy := sdl.JoystickOpen(0)
defer joy.Close()

h, err := sdl.HapticOpenFromJoystick(joy)
defer h.Close()

e := sdl.HapticConstant{
	Type:      sdl.HAPTIC_CONSTANT,
	Direction: sdl.HapticDirection{Type: sdl.HAPTIC_CARTESIAN, Dir: [3]int32{-1, 0}},
	Length:    1000,
	Level:     32767,
}

he := sdl.HapticEffect{}
*((*sdl.HapticConstant)(unsafe.Pointer(&he[0]))) = e

id, err := h.NewEffect(&he)
if err != nil {
	panic(err)
}
defer h.DestroyEffect(id)

h.RunEffect(id, 1)

time.Sleep(2 * time.Second)

We should probably make functions to update HapticEffect with actual effects or think of some other way of creating them in the first place.

This one might be redundant in that case, not sure what it is used for:

func (he HapticEffect) SetType(typ uint16) {}

[theGeekPirate]

From both my PS3 and XB One controllers using your code:

panic: Haptic: Effect not supported by haptic device.

Tried changing the Type just in case, but to no avail.

My original goal was to have the left/right sides rumble independently.

Have you been able to get it working with an sdl.GameController?

[theGeekPirate]

I should probably mention that a regular sdl.Haptic.RumblePlay() does work on both controllers (I'm on Linux).

[malashin]

@theGeekPirate ye, the first thing I tested on was Xbox One Gamepad.

Most of the gamepads don't support complex effects, the only thing they can run is
https://wiki.libsdl.org/SDL_HapticLeftRight

In my case it's just low and high frequency motors, nothing directional.

err := sdl.Init(sdl.INIT_EVERYTHING)
if err != nil {
	panic(err)
}

joy := sdl.JoystickOpen(0)
defer joy.Close()

h, err := sdl.HapticOpenFromJoystick(joy)
defer h.Close()


// Test low frequency motor.
e := sdl.HapticLeftRight{Type: sdl.HAPTIC_LEFTRIGHT,
	Length:         3000,
	LargeMagnitude: 32767,
	SmallMagnitude: 0,
}

he := sdl.HapticEffect{}
*((*sdl.HapticLeftRight)(unsafe.Pointer(&he[0]))) = e

id, err := h.NewEffect(&he)
if err != nil {
	panic(err)
}
h.RunEffect(id, 1)

time.Sleep(3 * time.Second)
h.DestroyEffect(id)


// Test high frequency motor.
e = sdl.HapticLeftRight{Type: sdl.HAPTIC_LEFTRIGHT,
	Length:         3000,
	LargeMagnitude: 0,
	SmallMagnitude: 32767,
}
*((*sdl.HapticLeftRight)(unsafe.Pointer(&he[0]))) = e

id, err = h.NewEffect(&he)
if err != nil {
	panic(err)
}
defer h.DestroyEffect(id)
h.RunEffect(id, 1)

time.Sleep(3 * time.Second)

This is what rumble does in SDL sources:

/* Most things can use SINE, but XInput only has LEFTRIGHT. */

if (haptic->supported & SDL_HAPTIC_SINE) {
    efx->type = SDL_HAPTIC_SINE;
    efx->periodic.period = 1000;
    efx->periodic.magnitude = 0x4000;
    efx->periodic.length = 5000;
    efx->periodic.attack_length = 0;
    efx->periodic.fade_length = 0;
} else if (haptic->supported & SDL_HAPTIC_LEFTRIGHT) {  /* XInput? */
    efx->type = SDL_HAPTIC_LEFTRIGHT;
    efx->leftright.length = 5000;
    efx->leftright.large_magnitude = 0x4000;
    efx->leftright.small_magnitude = 0x4000;
} else {
    return SDL_SetError("Device doesn't support rumble");
}

Directional effects work on Logitech G27 Racing Wheel.

[theGeekPirate]

Interesting, I wonder if your first example doesn't work because SDL2 is detecting it as an XInput device instead of an XB One controller.

Thanks for pasting working examples, made testing much easier!

Out of curiosity, which OS are you running?

[theGeekPirate]

Also, is there any reason you use sdl.Joystick instead of an sdl.GameController?

Best practice, or preference?

[malashin]

@theGeekPirate

Interesting, I wonder if your first example doesn't work because SDL2 is detecting it as an XInput device instead of an XB One controller.

As far as I remember is that if you open it as gamepad instead of joystick it will recognize it as Xbox One Contoller. But the example doesn't work because the gamepad doesn't support those effects. XInput is Microsofts API for Xbox Controller, and many other gamepads use it now, instead of legacy DirectInput.

[theGeekPirate]

Oh neat, thanks for the information! FWIW, using sdl.GameController still returns the Name as XInput Controller.

[malashin]

@theGeekPirate

Also, is there any reason you use the sdl.Joystick instead of an sdl.GameController?

The first example was used to test directional effects and since they don't work with gamepads I had to use joystick.

Joysticks are all the peripheral devices like wheels, joysticks, pedals, gamepads. GameController is still a joystick but have different functions and you might not find needed one in GameController methods. You are better off opening it as a GameController and returning sdl.Joystick with this function if needed:

// Joystick returns the Joystick ID from a Game Controller. The game controller builds on the Joystick API, but to be able to use the Joystick's functions with a gamepad, you need to use this first to get the joystick object.
// (https://wiki.libsdl.org/SDL_GameControllerGetJoystick)
func (ctrl *GameController) Joystick() *Joystick {}

HapticOpenFromJoystick() was used in the examples, but there is no equivalent of it for GameControllers. Also I did not need any GameController methods, so it was not opened as one.

// HapticOpenFromJoystick opens a haptic device for use from a joystick device.
// (https://wiki.libsdl.org/SDL_HapticOpenFromJoystick)
func HapticOpenFromJoystick(joy *Joystick) (*Haptic, error) {}

[malashin]

@theGeekPirate
There is no need for sdl.HapticEffect{} now, pass pointer to sdl.HapticLeftRight{} instead of it.

Check #316 for details.