src/haptic/windows/SDL_syshaptic.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "../../SDL_internal.h"

#ifdef SDL_HAPTIC_DINPUT

#include "SDL_assert.h"
#include "SDL_thread.h"
#include "SDL_mutex.h"
#include "SDL_timer.h"
#include "SDL_hints.h"
#include "SDL_haptic.h"
#include "../SDL_syshaptic.h"
#include "SDL_joystick.h"
#include "../../joystick/SDL_sysjoystick.h"     /* For the real SDL_Joystick */
#include "../../joystick/windows/SDL_dxjoystick_c.h"      /* For joystick hwdata */

#include "SDL_syshaptic_c.h"

/*
 * List of available haptic devices.
 */
typedef struct SDL_hapticlist_item
{
    DIDEVICEINSTANCE instance;
    char *name;
    SDL_Haptic *haptic;
    DIDEVCAPS capabilities;
    Uint8 bXInputHaptic; /* Supports force feedback via XInput. */
    Uint8 userid; /* XInput userid index for this joystick */
    struct SDL_hapticlist_item *next;
} SDL_hapticlist_item;


/*
 * Haptic system hardware data.
 */
struct haptic_hwdata
{
    LPDIRECTINPUTDEVICE8 device;
    DWORD axes[3];              /* Axes to use. */
    SDL_bool is_joystick;       /* Device is loaded as joystick. */
    Uint8 bXInputHaptic; /* Supports force feedback via XInput. */
    Uint8 userid; /* XInput userid index for this joystick */
    SDL_Thread *thread;
    SDL_mutex *mutex;
    volatile Uint32 stopTicks;
    volatile int stopThread;
};


/*
 * Haptic system effect data.
 */
struct haptic_hweffect
{
    DIEFFECT effect;
    LPDIRECTINPUTEFFECT ref;
    XINPUT_VIBRATION vibration;
};


/*
 * Internal stuff.
 */
static SDL_bool coinitialized = SDL_FALSE;
static LPDIRECTINPUT8 dinput = NULL;
static SDL_bool loaded_xinput = SDL_FALSE;
static SDL_hapticlist_item *SDL_hapticlist = NULL;
static SDL_hapticlist_item *SDL_hapticlist_tail = NULL;
static int numhaptics = 0;

/*
 * External stuff.
 */
extern HWND SDL_HelperWindow;


/*
 * Prototypes.
 */
static int DI_SetError(const char *str, HRESULT err);
static int DI_GUIDIsSame(const GUID * a, const GUID * b);
static int SDL_SYS_HapticOpenFromInstance(SDL_Haptic * haptic,
                                          DIDEVICEINSTANCE instance);
static int SDL_SYS_HapticOpenFromDevice8(SDL_Haptic * haptic,
                                         LPDIRECTINPUTDEVICE8 device8,
                                         SDL_bool is_joystick);
static int SDL_SYS_HapticOpenFromXInput(SDL_Haptic * haptic, const Uint8 userid);
static DWORD DIGetTriggerButton(Uint16 button);
static int SDL_SYS_SetDirection(DIEFFECT * effect, SDL_HapticDirection * dir,
                                int naxes);
static int SDL_SYS_ToDIEFFECT(SDL_Haptic * haptic, DIEFFECT * dest,
                              SDL_HapticEffect * src);
static void SDL_SYS_HapticFreeDIEFFECT(DIEFFECT * effect, int type);
static REFGUID SDL_SYS_HapticEffectType(SDL_HapticEffect * effect);
static int SDLCALL SDL_RunXInputHaptic(void *arg);

/* Callbacks. */
static BOOL CALLBACK EnumHapticsCallback(const DIDEVICEINSTANCE *
                                         pdidInstance, VOID * pContext);
static BOOL CALLBACK DI_EffectCallback(LPCDIEFFECTINFO pei, LPVOID pv);


/*
 * Like SDL_SetError but for DX error codes.
 */
static int
DI_SetError(const char *str, HRESULT err)
{
    /*
       SDL_SetError("Haptic: %s - %s: %s", str,
       DXGetErrorString8A(err), DXGetErrorDescription8A(err));
     */
    return SDL_SetError("Haptic error %s", str);
}


/*
 * Checks to see if two GUID are the same.
 */
static int
DI_GUIDIsSame(const GUID * a, const GUID * b)
{
    return (SDL_memcmp(a, b, sizeof (GUID)) == 0);
}


/*
 * Initializes the haptic subsystem.
 */
int
SDL_SYS_HapticInit(void)
{
    const char *env = SDL_GetHint(SDL_HINT_XINPUT_ENABLED);
    HRESULT ret;
    HINSTANCE instance;

    if (dinput != NULL) {       /* Already open. */
        return SDL_SetError("Haptic: SubSystem already open.");
    }

    ret = WIN_CoInitialize();
    if (FAILED(ret)) {
        return DI_SetError("Coinitialize", ret);
    }

    coinitialized = SDL_TRUE;

    ret = CoCreateInstance(&CLSID_DirectInput8, NULL, CLSCTX_INPROC_SERVER,
                           &IID_IDirectInput8, (LPVOID) & dinput);
    if (FAILED(ret)) {
        SDL_SYS_HapticQuit();
        return DI_SetError("CoCreateInstance", ret);
    }

    /* Because we used CoCreateInstance, we need to Initialize it, first. */
    instance = GetModuleHandle(NULL);
    if (instance == NULL) {
        SDL_SYS_HapticQuit();
        return SDL_SetError("GetModuleHandle() failed with error code %d.",
                            GetLastError());
    }
    ret = IDirectInput8_Initialize(dinput, instance, DIRECTINPUT_VERSION);
    if (FAILED(ret)) {
        SDL_SYS_HapticQuit();
        return DI_SetError("Initializing DirectInput device", ret);
    }

    /* Look for haptic devices. */
    ret = IDirectInput8_EnumDevices(dinput,
                                   0,
                                   EnumHapticsCallback,
                                   NULL,
                                   DIEDFL_FORCEFEEDBACK |
                                   DIEDFL_ATTACHEDONLY);
    if (FAILED(ret)) {
        SDL_SYS_HapticQuit();
        return DI_SetError("Enumerating DirectInput devices", ret);
    }

    if (!env || SDL_atoi(env)) {
        loaded_xinput = (WIN_LoadXInputDLL() == 0);
    }

    if (loaded_xinput) {
        DWORD i;
        for (i = 0; i < SDL_XINPUT_MAX_DEVICES; i++) {
            XInputHaptic_MaybeAddDevice(i);
        }
    }

    return numhaptics;
}


int
DirectInputHaptic_MaybeAddDevice(const DIDEVICEINSTANCE * pdidInstance)
{
    HRESULT ret;
    LPDIRECTINPUTDEVICE8 device;
    const DWORD needflags = DIDC_ATTACHED | DIDC_FORCEFEEDBACK;
    DIDEVCAPS capabilities;
    SDL_hapticlist_item *item = NULL;

    if (dinput == NULL) {
        return -1;  /* not initialized. We'll pick these up on enumeration if we init later. */
    }

    /* Make sure we don't already have it */
    for (item = SDL_hapticlist; item; item = item->next) {
        if ( (!item->bXInputHaptic) && (SDL_memcmp(&item->instance, pdidInstance, sizeof (*pdidInstance)) == 0) ) {
            return -1;  /* Already added */
        }
    }

    /* Open the device */
    ret = IDirectInput8_CreateDevice(dinput, &pdidInstance->guidInstance, &device, NULL);
    if (FAILED(ret)) {
        /* DI_SetError("Creating DirectInput device",ret); */
        return -1;
    }

    /* Get capabilities. */
    SDL_zero(capabilities);
    capabilities.dwSize = sizeof (DIDEVCAPS);
    ret = IDirectInputDevice8_GetCapabilities(device, &capabilities);
    IDirectInputDevice8_Release(device);
    if (FAILED(ret)) {
        /* DI_SetError("Getting device capabilities",ret); */
        return -1;
    }

    if ((capabilities.dwFlags & needflags) != needflags) {
        return -1;  /* not a device we can use. */
    }

    item = (SDL_hapticlist_item *)SDL_calloc(1, sizeof(SDL_hapticlist_item));
    if (item == NULL) {
        return SDL_OutOfMemory();
    }

    item->name = WIN_StringToUTF8(pdidInstance->tszProductName);
    if (!item->name) {
        SDL_free(item);
        return -1;
    }

    /* Copy the instance over, useful for creating devices. */
    SDL_memcpy(&item->instance, pdidInstance, sizeof (DIDEVICEINSTANCE));
    SDL_memcpy(&item->capabilities, &capabilities, sizeof (capabilities));

    if (SDL_hapticlist_tail == NULL) {
        SDL_hapticlist = SDL_hapticlist_tail = item;
    } else {
        SDL_hapticlist_tail->next = item;
        SDL_hapticlist_tail = item;
    }

    /* Device has been added. */
    ++numhaptics;

    return numhaptics;
}


int
DirectInputHaptic_MaybeRemoveDevice(const DIDEVICEINSTANCE * pdidInstance)
{
    SDL_hapticlist_item *item;
    SDL_hapticlist_item *prev = NULL;

    if (dinput == NULL) {
        return -1;  /* not initialized, ignore this. */
    }

    for (item = SDL_hapticlist; item != NULL; item = item->next) {
        if ( (!item->bXInputHaptic) && (SDL_memcmp(&item->instance, pdidInstance, sizeof (*pdidInstance)) == 0) ) {
            /* found it, remove it. */
            const int retval = item->haptic ? item->haptic->index : -1;
            if (prev != NULL) {
                prev->next = item->next;
            } else {
                SDL_assert(SDL_hapticlist == item);
                SDL_hapticlist = item->next;
            }
            if (item == SDL_hapticlist_tail) {
                SDL_hapticlist_tail = prev;
            }
            --numhaptics;
            /* !!! TODO: Send a haptic remove event? */
            SDL_free(item);
            return retval;
        }
        prev = item;
    }

    return -1;
}


int
XInputHaptic_MaybeAddDevice(const DWORD dwUserid)
{
    const Uint8 userid = (Uint8) dwUserid;
    SDL_hapticlist_item *item;
    XINPUT_VIBRATION state;

    if ((!loaded_xinput) || (dwUserid >= SDL_XINPUT_MAX_DEVICES)) {
        return -1;
    }

    /* Make sure we don't already have it */
    for (item = SDL_hapticlist; item; item = item->next) {
        if ((item->bXInputHaptic) && (item->userid == userid)) {
            return -1;  /* Already added */
        }
    }

    SDL_zero(state);
    if (XINPUTSETSTATE(dwUserid, &state) != ERROR_SUCCESS) {
        return -1;  /* no force feedback on this device. */
    }

    item = (SDL_hapticlist_item *)SDL_malloc( sizeof(SDL_hapticlist_item));
    if (item == NULL) {
        return SDL_OutOfMemory();
    }

    SDL_zerop(item);

    /* !!! FIXME: I'm not bothering to query for a real name right now (can we even?) */
    {
        char buf[64];
        SDL_snprintf(buf, sizeof (buf), "XInput Controller #%u", (unsigned int) (userid+1));
        item->name = SDL_strdup(buf);
    }

    if (!item->name) {
        SDL_free(item);
        return -1;
    }

    /* Copy the instance over, useful for creating devices. */
    item->bXInputHaptic = 1;
    item->userid = userid;

    if (SDL_hapticlist_tail == NULL) {
        SDL_hapticlist = SDL_hapticlist_tail = item;
    } else {
        SDL_hapticlist_tail->next = item;
        SDL_hapticlist_tail = item;
    }

    /* Device has been added. */
    ++numhaptics;

    return numhaptics;
}


int
XInputHaptic_MaybeRemoveDevice(const DWORD dwUserid)
{
    const Uint8 userid = (Uint8) dwUserid;
    SDL_hapticlist_item *item;
    SDL_hapticlist_item *prev = NULL;

    if ((!loaded_xinput) || (dwUserid >= SDL_XINPUT_MAX_DEVICES)) {
        return -1;
    }

    for (item = SDL_hapticlist; item != NULL; item = item->next) {
        if ((item->bXInputHaptic) && (item->userid == userid)) {
            /* found it, remove it. */
            const int retval = item->haptic ? item->haptic->index : -1;
            if (prev != NULL) {
                prev->next = item->next;
            } else {
                SDL_assert(SDL_hapticlist == item);
                SDL_hapticlist = item->next;
            }
            if (item == SDL_hapticlist_tail) {
                SDL_hapticlist_tail = prev;
            }
            --numhaptics;
            /* !!! TODO: Send a haptic remove event? */
            SDL_free(item);
            return retval;
        }
        prev = item;
    }

    return -1;
}


/*
 * Callback to find the haptic devices.
 */
static BOOL CALLBACK
EnumHapticsCallback(const DIDEVICEINSTANCE * pdidInstance, VOID * pContext)
{
    (void) pContext;
    DirectInputHaptic_MaybeAddDevice(pdidInstance);
    return DIENUM_CONTINUE;  /* continue enumerating */
}


int
SDL_SYS_NumHaptics()
{
    return numhaptics;
}

static SDL_hapticlist_item *
HapticByDevIndex(int device_index)
{
    SDL_hapticlist_item *item = SDL_hapticlist;

    if ((device_index < 0) || (device_index >= numhaptics)) {
        return NULL;
    }

    while (device_index > 0) {
        SDL_assert(item != NULL);
        --device_index;
        item = item->next;
    }

    return item;
}

/*
 * Return the name of a haptic device, does not need to be opened.
 */
const char *
SDL_SYS_HapticName(int index)
{
    SDL_hapticlist_item *item = HapticByDevIndex(index);
    return item->name;
}


/*
 * Callback to get all supported effects.
 */
#define EFFECT_TEST(e,s)               \
if (DI_GUIDIsSame(&pei->guid, &(e)))   \
   haptic->supported |= (s)
static BOOL CALLBACK
DI_EffectCallback(LPCDIEFFECTINFO pei, LPVOID pv)
{
    /* Prepare the haptic device. */
    SDL_Haptic *haptic = (SDL_Haptic *) pv;

    /* Get supported. */
    EFFECT_TEST(GUID_Spring, SDL_HAPTIC_SPRING);
    EFFECT_TEST(GUID_Damper, SDL_HAPTIC_DAMPER);
    EFFECT_TEST(GUID_Inertia, SDL_HAPTIC_INERTIA);
    EFFECT_TEST(GUID_Friction, SDL_HAPTIC_FRICTION);
    EFFECT_TEST(GUID_ConstantForce, SDL_HAPTIC_CONSTANT);
    EFFECT_TEST(GUID_CustomForce, SDL_HAPTIC_CUSTOM);
    EFFECT_TEST(GUID_Sine, SDL_HAPTIC_SINE);
    /* !!! FIXME: put this back when we have more bits in 2.1 */
    /* EFFECT_TEST(GUID_Square, SDL_HAPTIC_SQUARE); */
    EFFECT_TEST(GUID_Triangle, SDL_HAPTIC_TRIANGLE);
    EFFECT_TEST(GUID_SawtoothUp, SDL_HAPTIC_SAWTOOTHUP);
    EFFECT_TEST(GUID_SawtoothDown, SDL_HAPTIC_SAWTOOTHDOWN);
    EFFECT_TEST(GUID_RampForce, SDL_HAPTIC_RAMP);

    /* Check for more. */
    return DIENUM_CONTINUE;
}


/*
 * Callback to get supported axes.
 */
static BOOL CALLBACK
DI_DeviceObjectCallback(LPCDIDEVICEOBJECTINSTANCE dev, LPVOID pvRef)
{
    SDL_Haptic *haptic = (SDL_Haptic *) pvRef;

    if ((dev->dwType & DIDFT_AXIS) && (dev->dwFlags & DIDOI_FFACTUATOR)) {
        const GUID *guid = &dev->guidType;
        DWORD offset = 0;
        if (DI_GUIDIsSame(guid, &GUID_XAxis)) {
            offset = DIJOFS_X;
        } else if (DI_GUIDIsSame(guid, &GUID_YAxis)) {
            offset = DIJOFS_Y;
        } else if (DI_GUIDIsSame(guid, &GUID_ZAxis)) {
            offset = DIJOFS_Z;
        } else if (DI_GUIDIsSame(guid, &GUID_RxAxis)) {
            offset = DIJOFS_RX;
        } else if (DI_GUIDIsSame(guid, &GUID_RyAxis)) {
            offset = DIJOFS_RY;
        } else if (DI_GUIDIsSame(guid, &GUID_RzAxis)) {
            offset = DIJOFS_RZ;
        } else {
            return DIENUM_CONTINUE;   /* can't use this, go on. */
        }

        haptic->hwdata->axes[haptic->naxes] = offset;
        haptic->naxes++;

        /* Currently using the artificial limit of 3 axes. */
        if (haptic->naxes >= 3) {
            return DIENUM_STOP;
        }
    }

    return DIENUM_CONTINUE;
}


/*
 * Opens the haptic device from the file descriptor.
 *
 *    Steps:
 *       - Open temporary DirectInputDevice interface.
 *       - Create DirectInputDevice8 interface.
 *       - Release DirectInputDevice interface.
 *       - Call SDL_SYS_HapticOpenFromDevice8
 */
static int
SDL_SYS_HapticOpenFromInstance(SDL_Haptic * haptic, DIDEVICEINSTANCE instance)
{
    HRESULT ret;
    int ret2;
    LPDIRECTINPUTDEVICE8 device;
    LPDIRECTINPUTDEVICE8 device8;

    /* Open the device */
    ret = IDirectInput8_CreateDevice(dinput, &instance.guidInstance,
                                    &device, NULL);
    if (FAILED(ret)) {
        DI_SetError("Creating DirectInput device", ret);
        return -1;
    }

    /* Now get the IDirectInputDevice8 interface, instead. */
    ret = IDirectInputDevice8_QueryInterface(device,
                                            &IID_IDirectInputDevice8,
                                            (LPVOID *) &device8);
    /* Done with the temporary one now. */
    IDirectInputDevice8_Release(device);
    if (FAILED(ret)) {
        DI_SetError("Querying DirectInput interface", ret);
        return -1;
    }

    ret2 = SDL_SYS_HapticOpenFromDevice8(haptic, device8, SDL_FALSE);
    if (ret2 < 0) {
        IDirectInputDevice8_Release(device8);
        return -1;
    }

    return 0;
}

static int
SDL_SYS_HapticOpenFromXInput(SDL_Haptic *haptic, const Uint8 userid)
{
    char threadName[32];
    XINPUT_VIBRATION vibration = { 0, 0 };  /* stop any current vibration */
    XINPUTSETSTATE(userid, &vibration);

    haptic->supported = SDL_HAPTIC_LEFTRIGHT;

    haptic->neffects = 1;
    haptic->nplaying = 1;

    /* Prepare effects memory. */
    haptic->effects = (struct haptic_effect *)
        SDL_malloc(sizeof(struct haptic_effect) * haptic->neffects);
    if (haptic->effects == NULL) {
        return SDL_OutOfMemory();
    }
    /* Clear the memory */
    SDL_memset(haptic->effects, 0,
               sizeof(struct haptic_effect) * haptic->neffects);

    haptic->hwdata = (struct haptic_hwdata *) SDL_malloc(sizeof(*haptic->hwdata));
    if (haptic->hwdata == NULL) {
        SDL_free(haptic->effects);
        haptic->effects = NULL;
        return SDL_OutOfMemory();
    }
    SDL_memset(haptic->hwdata, 0, sizeof(*haptic->hwdata));

    haptic->hwdata->bXInputHaptic = 1;
    haptic->hwdata->userid = userid;

    haptic->hwdata->mutex = SDL_CreateMutex();
    if (haptic->hwdata->mutex == NULL) {
        SDL_free(haptic->effects);
        SDL_free(haptic->hwdata);
        haptic->effects = NULL;
        return SDL_SetError("Couldn't create XInput haptic mutex");
    }

    SDL_snprintf(threadName, sizeof (threadName), "SDLXInputDev%d", (int) userid);

#if defined(__WIN32__) && !defined(HAVE_LIBC)  /* !!! FIXME: this is nasty. */
    #undef SDL_CreateThread
    #if SDL_DYNAMIC_API
    haptic->hwdata->thread = SDL_CreateThread_REAL(SDL_RunXInputHaptic, threadName, haptic->hwdata, NULL, NULL);
    #else
    haptic->hwdata->thread = SDL_CreateThread(SDL_RunXInputHaptic, threadName, haptic->hwdata, NULL, NULL);
    #endif
#else
    haptic->hwdata->thread = SDL_CreateThread(SDL_RunXInputHaptic, threadName, haptic->hwdata);
#endif
    if (haptic->hwdata->thread == NULL) {
        SDL_DestroyMutex(haptic->hwdata->mutex);
        SDL_free(haptic->effects);
        SDL_free(haptic->hwdata);
        haptic->effects = NULL;
        return SDL_SetError("Couldn't create XInput haptic thread");
    }

    return 0;
 }

/*
 * Opens the haptic device from the file descriptor.
 *
 *    Steps:
 *       - Set cooperative level.
 *       - Set data format.
 *       - Acquire exclusiveness.
 *       - Reset actuators.
 *       - Get supported features.
 */
static int
SDL_SYS_HapticOpenFromDevice8(SDL_Haptic * haptic,
                              LPDIRECTINPUTDEVICE8 device8, SDL_bool is_joystick)
{
    HRESULT ret;
    DIPROPDWORD dipdw;

    /* Allocate the hwdata */
    haptic->hwdata = (struct haptic_hwdata *)SDL_malloc(sizeof(*haptic->hwdata));
    if (haptic->hwdata == NULL) {
        return SDL_OutOfMemory();
    }
    SDL_memset(haptic->hwdata, 0, sizeof(*haptic->hwdata));

    /* We'll use the device8 from now on. */
    haptic->hwdata->device = device8;
    haptic->hwdata->is_joystick = is_joystick;

    /* !!! FIXME: opening a haptic device here first will make an attempt to
       !!! FIXME:  SDL_JoystickOpen() that same device fail later, since we
       !!! FIXME:  have it open in exclusive mode. But this will allow
       !!! FIXME:  SDL_JoystickOpen() followed by SDL_HapticOpenFromJoystick()
       !!! FIXME:  to work, and that's probably the common case. Still,
       !!! FIXME:  ideally, We need to unify the opening code. */

    if (!is_joystick) {  /* if is_joystick, we already set this up elsewhere. */
        /* Grab it exclusively to use force feedback stuff. */
        ret = IDirectInputDevice8_SetCooperativeLevel(haptic->hwdata->device,
                                                      SDL_HelperWindow,
                                                      DISCL_EXCLUSIVE |
                                                      DISCL_BACKGROUND);
        if (FAILED(ret)) {
            DI_SetError("Setting cooperative level to exclusive", ret);
            goto acquire_err;
        }

        /* Set data format. */
        ret = IDirectInputDevice8_SetDataFormat(haptic->hwdata->device,
                                                &c_dfDIJoystick2);
        if (FAILED(ret)) {
            DI_SetError("Setting data format", ret);
            goto acquire_err;
        }

        /* Get number of axes. */
        ret = IDirectInputDevice8_EnumObjects(haptic->hwdata->device,
                                              DI_DeviceObjectCallback,
                                              haptic, DIDFT_AXIS);
        if (FAILED(ret)) {
            DI_SetError("Getting device axes", ret);
            goto acquire_err;
        }

        /* Acquire the device. */
        ret = IDirectInputDevice8_Acquire(haptic->hwdata->device);
        if (FAILED(ret)) {
            DI_SetError("Acquiring DirectInput device", ret);
            goto acquire_err;
        }
    }

    /* Reset all actuators - just in case. */
    ret = IDirectInputDevice8_SendForceFeedbackCommand(haptic->hwdata->device,
                                                       DISFFC_RESET);
    if (FAILED(ret)) {
        DI_SetError("Resetting device", ret);
        goto acquire_err;
    }

    /* Enabling actuators. */
    ret = IDirectInputDevice8_SendForceFeedbackCommand(haptic->hwdata->device,
                                                       DISFFC_SETACTUATORSON);
    if (FAILED(ret)) {
        DI_SetError("Enabling actuators", ret);
        goto acquire_err;
    }

    /* Get supported effects. */
    ret = IDirectInputDevice8_EnumEffects(haptic->hwdata->device,
                                          DI_EffectCallback, haptic,
                                          DIEFT_ALL);
    if (FAILED(ret)) {
        DI_SetError("Enumerating supported effects", ret);
        goto acquire_err;
    }
    if (haptic->supported == 0) {       /* Error since device supports nothing. */
        SDL_SetError("Haptic: Internal error on finding supported effects.");
        goto acquire_err;
    }

    /* Check autogain and autocenter. */
    dipdw.diph.dwSize = sizeof(DIPROPDWORD);
    dipdw.diph.dwHeaderSize = sizeof(DIPROPHEADER);
    dipdw.diph.dwObj = 0;
    dipdw.diph.dwHow = DIPH_DEVICE;
    dipdw.dwData = 10000;
    ret = IDirectInputDevice8_SetProperty(haptic->hwdata->device,
                                          DIPROP_FFGAIN, &dipdw.diph);
    if (!FAILED(ret)) {         /* Gain is supported. */
        haptic->supported |= SDL_HAPTIC_GAIN;
    }
    dipdw.diph.dwObj = 0;
    dipdw.diph.dwHow = DIPH_DEVICE;
    dipdw.dwData = DIPROPAUTOCENTER_OFF;
    ret = IDirectInputDevice8_SetProperty(haptic->hwdata->device,
                                          DIPROP_AUTOCENTER, &dipdw.diph);
    if (!FAILED(ret)) {         /* Autocenter is supported. */
        haptic->supported |= SDL_HAPTIC_AUTOCENTER;
    }

    /* Status is always supported. */
    haptic->supported |= SDL_HAPTIC_STATUS | SDL_HAPTIC_PAUSE;

    /* Check maximum effects. */
    haptic->neffects = 128;     /* This is not actually supported as thus under windows,
                                   there is no way to tell the number of EFFECTS that a
                                   device can hold, so we'll just use a "random" number
                                   instead and put warnings in SDL_haptic.h */
    haptic->nplaying = 128;     /* Even more impossible to get this then neffects. */

    /* Prepare effects memory. */
    haptic->effects = (struct haptic_effect *)
        SDL_malloc(sizeof(struct haptic_effect) * haptic->neffects);
    if (haptic->effects == NULL) {
        SDL_OutOfMemory();
        goto acquire_err;
    }
    /* Clear the memory */
    SDL_memset(haptic->effects, 0,
               sizeof(struct haptic_effect) * haptic->neffects);

    return 0;

    /* Error handling */
  acquire_err:
    IDirectInputDevice8_Unacquire(haptic->hwdata->device);
    return -1;

}


/*
 * Opens a haptic device for usage.
 */
int
SDL_SYS_HapticOpen(SDL_Haptic * haptic)
{
    SDL_hapticlist_item *item = HapticByDevIndex(haptic->index);
    return (item->bXInputHaptic) ? SDL_SYS_HapticOpenFromXInput(haptic, item->userid) : SDL_SYS_HapticOpenFromInstance(haptic, item->instance);
}


/*
 * Opens a haptic device from first mouse it finds for usage.
 */
int
SDL_SYS_HapticMouse(void)
{
    SDL_hapticlist_item *item;
    int index = 0;

    /* Grab the first mouse haptic device we find. */
    for (item = SDL_hapticlist; item != NULL; item = item->next) {
        SDL_assert(index >= 0);
        if (item->capabilities.dwDevType == DI8DEVCLASS_POINTER ) {
            return index;
        }
        ++index;
    }

    return -1;
}


/*
 * Checks to see if a joystick has haptic features.
 */
int
SDL_SYS_JoystickIsHaptic(SDL_Joystick * joystick)
{
    const struct joystick_hwdata *hwdata = joystick->hwdata;
    return ( (hwdata->bXInputHaptic) ||
             ((hwdata->Capabilities.dwFlags & DIDC_FORCEFEEDBACK) != 0) );
}


/*
 * Checks to see if the haptic device and joystick are in reality the same.
 */
int
SDL_SYS_JoystickSameHaptic(SDL_Haptic * haptic, SDL_Joystick * joystick)
{
    if (joystick->hwdata->bXInputHaptic != haptic->hwdata->bXInputHaptic) {
        return 0;  /* one is XInput, one is not; not the same device. */
    } else if (joystick->hwdata->bXInputHaptic) {  /* XInput */
        return (haptic->hwdata->userid == joystick->hwdata->userid);
    } else {  /* DirectInput */
        HRESULT ret;
        DIDEVICEINSTANCE hap_instance, joy_instance;

        hap_instance.dwSize = sizeof(DIDEVICEINSTANCE);
        joy_instance.dwSize = sizeof(DIDEVICEINSTANCE);

        /* Get the device instances. */
        ret = IDirectInputDevice8_GetDeviceInfo(haptic->hwdata->device,
                                            &hap_instance);
        if (FAILED(ret)) {
            return 0;
        }
        ret = IDirectInputDevice8_GetDeviceInfo(joystick->hwdata->InputDevice,
                                                &joy_instance);
        if (FAILED(ret)) {
            return 0;
        }

        if (DI_GUIDIsSame(&hap_instance.guidInstance, &joy_instance.guidInstance))
            return 1;
    }

    return 0;
}


/*
 * Opens a SDL_Haptic from a SDL_Joystick.
 */
int
SDL_SYS_HapticOpenFromJoystick(SDL_Haptic * haptic, SDL_Joystick * joystick)
{
    SDL_hapticlist_item *item;
    int index = 0;

    /* Since it comes from a joystick we have to try to match it with a haptic device on our haptic list. */
    if (joystick->hwdata->bXInputDevice) {
        const Uint8 userid = joystick->hwdata->userid;
        for (item = SDL_hapticlist; item != NULL; item = item->next) {
            if ((item->bXInputHaptic) && (item->userid == userid)) {
                SDL_assert(joystick->hwdata->bXInputHaptic);
                haptic->index = index;
                return SDL_SYS_HapticOpenFromXInput(haptic, userid);
            }
            ++index;
        }
    } else {
        HRESULT idret;
        DIDEVICEINSTANCE joy_instance;

        joy_instance.dwSize = sizeof(DIDEVICEINSTANCE);
        idret = IDirectInputDevice8_GetDeviceInfo(joystick->hwdata->InputDevice, &joy_instance);
        if (FAILED(idret)) {
            return -1;
        }

        for (item = SDL_hapticlist; item != NULL; item = item->next) {
            if (DI_GUIDIsSame(&item->instance.guidInstance, &joy_instance.guidInstance)) {
                haptic->index = index;
                return SDL_SYS_HapticOpenFromDevice8(haptic, joystick->hwdata->InputDevice, SDL_TRUE);
            }
            ++index;
        }
    }

    /* No match to our haptic list */
    return -1;
}


/*
 * Closes the haptic device.
 */
void
SDL_SYS_HapticClose(SDL_Haptic * haptic)
{
    if (haptic->hwdata) {

        /* Free effects. */
        SDL_free(haptic->effects);
        haptic->effects = NULL;
        haptic->neffects = 0;

        /* Clean up */
        if (haptic->hwdata->bXInputHaptic) {
            haptic->hwdata->stopThread = 1;
            SDL_WaitThread(haptic->hwdata->thread, NULL);
            SDL_DestroyMutex(haptic->hwdata->mutex);
        } else {
            IDirectInputDevice8_Unacquire(haptic->hwdata->device);
            /* Only release if isn't grabbed by a joystick. */
            if (haptic->hwdata->is_joystick == 0) {
                IDirectInputDevice8_Release(haptic->hwdata->device);
            }
        }

        /* Free */
        SDL_free(haptic->hwdata);
        haptic->hwdata = NULL;
    }
}


/*
 * Clean up after system specific haptic stuff
 */
void
SDL_SYS_HapticQuit(void)
{
    SDL_hapticlist_item *item;
    SDL_hapticlist_item *next = NULL;
    SDL_Haptic *hapticitem = NULL;

    extern SDL_Haptic *SDL_haptics;
    for (hapticitem = SDL_haptics; hapticitem; hapticitem = hapticitem->next) {
        if ((hapticitem->hwdata->bXInputHaptic) && (hapticitem->hwdata->thread)) {
            /* we _have_ to stop the thread before we free the XInput DLL! */
            hapticitem->hwdata->stopThread = 1;
            SDL_WaitThread(hapticitem->hwdata->thread, NULL);
            hapticitem->hwdata->thread = NULL;
        }
    }

    for (item = SDL_hapticlist; item; item = next) {
        /* Opened and not closed haptics are leaked, this is on purpose.
         * Close your haptic devices after usage. */
        /* !!! FIXME: (...is leaking on purpose a good idea?) */
        next = item->next;
        SDL_free(item->name);
        SDL_free(item);
    }

    if (loaded_xinput) {
        WIN_UnloadXInputDLL();
        loaded_xinput = SDL_FALSE;
    }

    if (dinput != NULL) {
        IDirectInput8_Release(dinput);
        dinput = NULL;
    }

    if (coinitialized) {
        WIN_CoUninitialize();
        coinitialized = SDL_FALSE;
    }
}


/*
 * Converts an SDL trigger button to an DIEFFECT trigger button.
 */
static DWORD
DIGetTriggerButton(Uint16 button)
{
    DWORD dwTriggerButton;

    dwTriggerButton = DIEB_NOTRIGGER;

    if (button != 0) {
        dwTriggerButton = DIJOFS_BUTTON(button - 1);
    }

    return dwTriggerButton;
}


/*
 * Sets the direction.
 */
static int
SDL_SYS_SetDirection(DIEFFECT * effect, SDL_HapticDirection * dir, int naxes)
{
    LONG *rglDir;

    /* Handle no axes a part. */
    if (naxes == 0) {
        effect->dwFlags |= DIEFF_SPHERICAL;     /* Set as default. */
        effect->rglDirection = NULL;
        return 0;
    }

    /* Has axes. */
    rglDir = SDL_malloc(sizeof(LONG) * naxes);
    if (rglDir == NULL) {
        return SDL_OutOfMemory();
    }
    SDL_memset(rglDir, 0, sizeof(LONG) * naxes);
    effect->rglDirection = rglDir;

    switch (dir->type) {
    case SDL_HAPTIC_POLAR:
        effect->dwFlags |= DIEFF_POLAR;
        rglDir[0] = dir->dir[0];
        return 0;
    case SDL_HAPTIC_CARTESIAN:
        effect->dwFlags |= DIEFF_CARTESIAN;
        rglDir[0] = dir->dir[0];
        if (naxes > 1)
            rglDir[1] = dir->dir[1];
        if (naxes > 2)
            rglDir[2] = dir->dir[2];
        return 0;
    case SDL_HAPTIC_SPHERICAL:
        effect->dwFlags |= DIEFF_SPHERICAL;
        rglDir[0] = dir->dir[0];
        if (naxes > 1)
            rglDir[1] = dir->dir[1];
        if (naxes > 2)
            rglDir[2] = dir->dir[2];
        return 0;

    default:
        return SDL_SetError("Haptic: Unknown direction type.");
    }
}

#define CONVERT(x)   (((x) > 0x7FFF) ? 10000 : ((x)*10000) / 0x7FFF)
/*
 * Creates the DIEFFECT from a SDL_HapticEffect.
 */
static int
SDL_SYS_ToDIEFFECT(SDL_Haptic * haptic, DIEFFECT * dest,
                   SDL_HapticEffect * src)
{
    int i;
    DICONSTANTFORCE *constant;
    DIPERIODIC *periodic;
    DICONDITION *condition;     /* Actually an array of conditions - one per axis. */
    DIRAMPFORCE *ramp;
    DICUSTOMFORCE *custom;
    DIENVELOPE *envelope;
    SDL_HapticConstant *hap_constant;
    SDL_HapticPeriodic *hap_periodic;
    SDL_HapticCondition *hap_condition;
    SDL_HapticRamp *hap_ramp;
    SDL_HapticCustom *hap_custom;
    DWORD *axes;

    /* Set global stuff. */
    SDL_memset(dest, 0, sizeof(DIEFFECT));
    dest->dwSize = sizeof(DIEFFECT);    /* Set the structure size. */
    dest->dwSamplePeriod = 0;   /* Not used by us. */
    dest->dwGain = 10000;       /* Gain is set globally, not locally. */
    dest->dwFlags = DIEFF_OBJECTOFFSETS;        /* Seems obligatory. */

    /* Envelope. */
    envelope = SDL_malloc(sizeof(DIENVELOPE));
    if (envelope == NULL) {
        return SDL_OutOfMemory();
    }
    SDL_memset(envelope, 0, sizeof(DIENVELOPE));
    dest->lpEnvelope = envelope;
    envelope->dwSize = sizeof(DIENVELOPE);      /* Always should be this. */

    /* Axes. */
    dest->cAxes = haptic->naxes;
    if (dest->cAxes > 0) {
        axes = SDL_malloc(sizeof(DWORD) * dest->cAxes);
        if (axes == NULL) {
            return SDL_OutOfMemory();
        }
        axes[0] = haptic->hwdata->axes[0];      /* Always at least one axis. */
        if (dest->cAxes > 1) {
            axes[1] = haptic->hwdata->axes[1];
        }
        if (dest->cAxes > 2) {
            axes[2] = haptic->hwdata->axes[2];
        }
        dest->rgdwAxes = axes;
    }


    /* The big type handling switch, even bigger then Linux's version. */
    switch (src->type) {
    case SDL_HAPTIC_CONSTANT:
        hap_constant = &src->constant;
        constant = SDL_malloc(sizeof(DICONSTANTFORCE));
        if (constant == NULL) {
            return SDL_OutOfMemory();
        }
        SDL_memset(constant, 0, sizeof(DICONSTANTFORCE));

        /* Specifics */
        constant->lMagnitude = CONVERT(hap_constant->level);
        dest->cbTypeSpecificParams = sizeof(DICONSTANTFORCE);
        dest->lpvTypeSpecificParams = constant;

        /* Generics */
        dest->dwDuration = hap_constant->length * 1000; /* In microseconds. */
        dest->dwTriggerButton = DIGetTriggerButton(hap_constant->button);
        dest->dwTriggerRepeatInterval = hap_constant->interval;
        dest->dwStartDelay = hap_constant->delay * 1000;        /* In microseconds. */

        /* Direction. */
        if (SDL_SYS_SetDirection(dest, &hap_constant->direction, dest->cAxes)
            < 0) {
            return -1;
        }

        /* Envelope */
        if ((hap_constant->attack_length == 0)
            && (hap_constant->fade_length == 0)) {
            SDL_free(dest->lpEnvelope);
            dest->lpEnvelope = NULL;
        } else {
            envelope->dwAttackLevel = CONVERT(hap_constant->attack_level);
            envelope->dwAttackTime = hap_constant->attack_length * 1000;
            envelope->dwFadeLevel = CONVERT(hap_constant->fade_level);
            envelope->dwFadeTime = hap_constant->fade_length * 1000;
        }

        break;

    case SDL_HAPTIC_SINE:
    /* !!! FIXME: put this back when we have more bits in 2.1 */
    /* case SDL_HAPTIC_SQUARE: */
    case SDL_HAPTIC_TRIANGLE:
    case SDL_HAPTIC_SAWTOOTHUP:
    case SDL_HAPTIC_SAWTOOTHDOWN:
        hap_periodic = &src->periodic;
        periodic = SDL_malloc(sizeof(DIPERIODIC));
        if (periodic == NULL) {
            return SDL_OutOfMemory();
        }
        SDL_memset(periodic, 0, sizeof(DIPERIODIC));

        /* Specifics */
        periodic->dwMagnitude = CONVERT(hap_periodic->magnitude);
        periodic->lOffset = CONVERT(hap_periodic->offset);
        periodic->dwPhase = hap_periodic->phase;
        periodic->dwPeriod = hap_periodic->period * 1000;
        dest->cbTypeSpecificParams = sizeof(DIPERIODIC);
        dest->lpvTypeSpecificParams = periodic;

        /* Generics */
        dest->dwDuration = hap_periodic->length * 1000; /* In microseconds. */
        dest->dwTriggerButton = DIGetTriggerButton(hap_periodic->button);
        dest->dwTriggerRepeatInterval = hap_periodic->interval;
        dest->dwStartDelay = hap_periodic->delay * 1000;        /* In microseconds. */

        /* Direction. */
        if (SDL_SYS_SetDirection(dest, &hap_periodic->direction, dest->cAxes)
            < 0) {
            return -1;
        }

        /* Envelope */
        if ((hap_periodic->attack_length == 0)
            && (hap_periodic->fade_length == 0)) {
            SDL_free(dest->lpEnvelope);
            dest->lpEnvelope = NULL;
        } else {
            envelope->dwAttackLevel = CONVERT(hap_periodic->attack_level);
            envelope->dwAttackTime = hap_periodic->attack_length * 1000;
            envelope->dwFadeLevel = CONVERT(hap_periodic->fade_level);
            envelope->dwFadeTime = hap_periodic->fade_length * 1000;
        }

        break;

    case SDL_HAPTIC_SPRING:
    case SDL_HAPTIC_DAMPER:
    case SDL_HAPTIC_INERTIA:
    case SDL_HAPTIC_FRICTION:
        hap_condition = &src->condition;
        condition = SDL_malloc(sizeof(DICONDITION) * dest->cAxes);
        if (condition == NULL) {
            return SDL_OutOfMemory();
        }
        SDL_memset(condition, 0, sizeof(DICONDITION));

        /* Specifics */
        for (i = 0; i < (int) dest->cAxes; i++) {
            condition[i].lOffset = CONVERT(hap_condition->center[i]);
            condition[i].lPositiveCoefficient =
                CONVERT(hap_condition->right_coeff[i]);
            condition[i].lNegativeCoefficient =
                CONVERT(hap_condition->left_coeff[i]);
            condition[i].dwPositiveSaturation =
                CONVERT(hap_condition->right_sat[i]);
            condition[i].dwNegativeSaturation =
                CONVERT(hap_condition->left_sat[i]);
            condition[i].lDeadBand = CONVERT(hap_condition->deadband[i]);
        }
        dest->cbTypeSpecificParams = sizeof(DICONDITION) * dest->cAxes;
        dest->lpvTypeSpecificParams = condition;

        /* Generics */
        dest->dwDuration = hap_condition->length * 1000;        /* In microseconds. */
        dest->dwTriggerButton = DIGetTriggerButton(hap_condition->button);
        dest->dwTriggerRepeatInterval = hap_condition->interval;
        dest->dwStartDelay = hap_condition->delay * 1000;       /* In microseconds. */

        /* Direction. */
        if (SDL_SYS_SetDirection(dest, &hap_condition->direction, dest->cAxes)
            < 0) {
            return -1;
        }

        /* Envelope - Not actually supported by most CONDITION implementations. */
        SDL_free(dest->lpEnvelope);
        dest->lpEnvelope = NULL;

        break;

    case SDL_HAPTIC_RAMP:
        hap_ramp = &src->ramp;
        ramp = SDL_malloc(sizeof(DIRAMPFORCE));
        if (ramp == NULL) {
            return SDL_OutOfMemory();
        }
        SDL_memset(ramp, 0, sizeof(DIRAMPFORCE));

        /* Specifics */
        ramp->lStart = CONVERT(hap_ramp->start);
        ramp->lEnd = CONVERT(hap_ramp->end);
        dest->cbTypeSpecificParams = sizeof(DIRAMPFORCE);
        dest->lpvTypeSpecificParams = ramp;

        /* Generics */
        dest->dwDuration = hap_ramp->length * 1000;     /* In microseconds. */
        dest->dwTriggerButton = DIGetTriggerButton(hap_ramp->button);
        dest->dwTriggerRepeatInterval = hap_ramp->interval;
        dest->dwStartDelay = hap_ramp->delay * 1000;    /* In microseconds. */

        /* Direction. */
        if (SDL_SYS_SetDirection(dest, &hap_ramp->direction, dest->cAxes) < 0) {
            return -1;
        }

        /* Envelope */
        if ((hap_ramp->attack_length == 0) && (hap_ramp->fade_length == 0)) {
            SDL_free(dest->lpEnvelope);
            dest->lpEnvelope = NULL;
        } else {
            envelope->dwAttackLevel = CONVERT(hap_ramp->attack_level);
            envelope->dwAttackTime = hap_ramp->attack_length * 1000;
            envelope->dwFadeLevel = CONVERT(hap_ramp->fade_level);
            envelope->dwFadeTime = hap_ramp->fade_length * 1000;
        }

        break;

    case SDL_HAPTIC_CUSTOM:
        hap_custom = &src->custom;
        custom = SDL_malloc(sizeof(DICUSTOMFORCE));
        if (custom == NULL) {
            return SDL_OutOfMemory();
        }
        SDL_memset(custom, 0, sizeof(DICUSTOMFORCE));

        /* Specifics */
        custom->cChannels = hap_custom->channels;
        custom->dwSamplePeriod = hap_custom->period * 1000;
        custom->cSamples = hap_custom->samples;
        custom->rglForceData =
            SDL_malloc(sizeof(LONG) * custom->cSamples * custom->cChannels);
        for (i = 0; i < hap_custom->samples * hap_custom->channels; i++) {      /* Copy data. */
            custom->rglForceData[i] = CONVERT(hap_custom->data[i]);
        }
        dest->cbTypeSpecificParams = sizeof(DICUSTOMFORCE);
        dest->lpvTypeSpecificParams = custom;

        /* Generics */
        dest->dwDuration = hap_custom->length * 1000;   /* In microseconds. */
        dest->dwTriggerButton = DIGetTriggerButton(hap_custom->button);
        dest->dwTriggerRepeatInterval = hap_custom->interval;
        dest->dwStartDelay = hap_custom->delay * 1000;  /* In microseconds. */

        /* Direction. */
        if (SDL_SYS_SetDirection(dest, &hap_custom->direction, dest->cAxes) <
            0) {
            return -1;
        }

        /* Envelope */
        if ((hap_custom->attack_length == 0)
            && (hap_custom->fade_length == 0)) {
            SDL_free(dest->lpEnvelope);
            dest->lpEnvelope = NULL;
        } else {
            envelope->dwAttackLevel = CONVERT(hap_custom->attack_level);
            envelope->dwAttackTime = hap_custom->attack_length * 1000;
            envelope->dwFadeLevel = CONVERT(hap_custom->fade_level);
            envelope->dwFadeTime = hap_custom->fade_length * 1000;
        }

        break;


    default:
        return SDL_SetError("Haptic: Unknown effect type.");
    }

    return 0;
}


/*
 * Frees an DIEFFECT allocated by SDL_SYS_ToDIEFFECT.
 */
static void
SDL_SYS_HapticFreeDIEFFECT(DIEFFECT * effect, int type)
{
    DICUSTOMFORCE *custom;

    SDL_free(effect->lpEnvelope);
    effect->lpEnvelope = NULL;
    SDL_free(effect->rgdwAxes);
    effect->rgdwAxes = NULL;
    if (effect->lpvTypeSpecificParams != NULL) {
        if (type == SDL_HAPTIC_CUSTOM) {        /* Must free the custom data. */
            custom = (DICUSTOMFORCE *) effect->lpvTypeSpecificParams;
            SDL_free(custom->rglForceData);
            custom->rglForceData = NULL;
        }
        SDL_free(effect->lpvTypeSpecificParams);
        effect->lpvTypeSpecificParams = NULL;
    }
    SDL_free(effect->rglDirection);
    effect->rglDirection = NULL;
}


/*
 * Gets the effect type from the generic SDL haptic effect wrapper.
 */
static REFGUID
SDL_SYS_HapticEffectType(SDL_HapticEffect * effect)
{
    switch (effect->type) {
    case SDL_HAPTIC_CONSTANT:
        return &GUID_ConstantForce;

    case SDL_HAPTIC_RAMP:
        return &GUID_RampForce;

    /* !!! FIXME: put this back when we have more bits in 2.1 */
    /* case SDL_HAPTIC_SQUARE:
        return &GUID_Square; */

    case SDL_HAPTIC_SINE:
        return &GUID_Sine;

    case SDL_HAPTIC_TRIANGLE:
        return &GUID_Triangle;

    case SDL_HAPTIC_SAWTOOTHUP:
        return &GUID_SawtoothUp;

    case SDL_HAPTIC_SAWTOOTHDOWN:
        return &GUID_SawtoothDown;

    case SDL_HAPTIC_SPRING:
        return &GUID_Spring;

    case SDL_HAPTIC_DAMPER:
        return &GUID_Damper;

    case SDL_HAPTIC_INERTIA:
        return &GUID_Inertia;

    case SDL_HAPTIC_FRICTION:
        return &GUID_Friction;

    case SDL_HAPTIC_CUSTOM:
        return &GUID_CustomForce;

    default:
        return NULL;
    }
}


/*
 * Creates a new haptic effect.
 */
int
SDL_SYS_HapticNewEffect(SDL_Haptic * haptic, struct haptic_effect *effect,
                        SDL_HapticEffect * base)
{
    HRESULT ret;
    REFGUID type = SDL_SYS_HapticEffectType(base);

    if ((type == NULL) && (!haptic->hwdata->bXInputHaptic)) {
        SDL_SetError("Haptic: Unknown effect type.");
        goto err_hweffect;
    }

    /* Alloc the effect. */
    effect->hweffect = (struct haptic_hweffect *)
        SDL_malloc(sizeof(struct haptic_hweffect));
    if (effect->hweffect == NULL) {
        SDL_OutOfMemory();
        goto err_hweffect;
    }

    SDL_zerop(effect->hweffect);

    if (haptic->hwdata->bXInputHaptic) {
        SDL_assert(base->type == SDL_HAPTIC_LEFTRIGHT);  /* should catch this at higher level */
        return SDL_SYS_HapticUpdateEffect(haptic, effect, base);
    }

    /* Get the effect. */
    if (SDL_SYS_ToDIEFFECT(haptic, &effect->hweffect->effect, base) < 0) {
        goto err_effectdone;
    }

    /* Create the actual effect. */
    ret = IDirectInputDevice8_CreateEffect(haptic->hwdata->device, type,
                                           &effect->hweffect->effect,
                                           &effect->hweffect->ref, NULL);
    if (FAILED(ret)) {
        DI_SetError("Unable to create effect", ret);
        goto err_effectdone;
    }

    return 0;

  err_effectdone:
    SDL_SYS_HapticFreeDIEFFECT(&effect->hweffect->effect, base->type);
  err_hweffect:
    SDL_free(effect->hweffect);
    effect->hweffect = NULL;
    return -1;
}


/*
 * Updates an effect.
 */
int
SDL_SYS_HapticUpdateEffect(SDL_Haptic * haptic,
                           struct haptic_effect *effect,
                           SDL_HapticEffect * data)
{
    HRESULT ret;
    DWORD flags;
    DIEFFECT temp;

    if (haptic->hwdata->bXInputHaptic) {
        XINPUT_VIBRATION *vib = &effect->hweffect->vibration;
        SDL_assert(data->type == SDL_HAPTIC_LEFTRIGHT);
        vib->wLeftMotorSpeed = data->leftright.large_magnitude;
        vib->wRightMotorSpeed = data->leftright.small_magnitude;
        SDL_LockMutex(haptic->hwdata->mutex);
        if (haptic->hwdata->stopTicks) {  /* running right now? Update it. */
            XINPUTSETSTATE(haptic->hwdata->userid, vib);
        }
        SDL_UnlockMutex(haptic->hwdata->mutex);
        return 0;
    }

    /* Get the effect. */
    SDL_memset(&temp, 0, sizeof(DIEFFECT));
    if (SDL_SYS_ToDIEFFECT(haptic, &temp, data) < 0) {
        goto err_update;
    }

    /* Set the flags.  Might be worthwhile to diff temp with loaded effect and
     *  only change those parameters. */
    flags = DIEP_DIRECTION |
        DIEP_DURATION |
        DIEP_ENVELOPE |
        DIEP_STARTDELAY |
        DIEP_TRIGGERBUTTON |
        DIEP_TRIGGERREPEATINTERVAL | DIEP_TYPESPECIFICPARAMS;

    /* Create the actual effect. */
    ret =
        IDirectInputEffect_SetParameters(effect->hweffect->ref, &temp, flags);
    if (FAILED(ret)) {
        DI_SetError("Unable to update effect", ret);
        goto err_update;
    }

    /* Copy it over. */
    SDL_SYS_HapticFreeDIEFFECT(&effect->hweffect->effect, data->type);
    SDL_memcpy(&effect->hweffect->effect, &temp, sizeof(DIEFFECT));

    return 0;

  err_update:
    SDL_SYS_HapticFreeDIEFFECT(&temp, data->type);
    return -1;
}


/*
 * Runs an effect.
 */
int
SDL_SYS_HapticRunEffect(SDL_Haptic * haptic, struct haptic_effect *effect,
                        Uint32 iterations)
{
    HRESULT ret;
    DWORD iter;

    if (haptic->hwdata->bXInputHaptic) {
        XINPUT_VIBRATION *vib = &effect->hweffect->vibration;
        SDL_assert(effect->effect.type == SDL_HAPTIC_LEFTRIGHT);  /* should catch this at higher level */
        SDL_LockMutex(haptic->hwdata->mutex);
        if(effect->effect.leftright.length == SDL_HAPTIC_INFINITY || iterations == SDL_HAPTIC_INFINITY) {
            haptic->hwdata->stopTicks = SDL_HAPTIC_INFINITY;
        } else if ((!effect->effect.leftright.length) || (!iterations)) {
            /* do nothing. Effect runs for zero milliseconds. */
        } else {
            haptic->hwdata->stopTicks = SDL_GetTicks() + (effect->effect.leftright.length * iterations);
            if ((haptic->hwdata->stopTicks == SDL_HAPTIC_INFINITY) || (haptic->hwdata->stopTicks == 0)) {
                haptic->hwdata->stopTicks = 1;  /* fix edge cases. */
            }
        }
        SDL_UnlockMutex(haptic->hwdata->mutex);
        return (XINPUTSETSTATE(haptic->hwdata->userid, vib) == ERROR_SUCCESS) ? 0 : -1;
    }

    /* Check if it's infinite. */
    if (iterations == SDL_HAPTIC_INFINITY) {
        iter = INFINITE;
    } else
        iter = iterations;

    /* Run the effect. */
    ret = IDirectInputEffect_Start(effect->hweffect->ref, iter, 0);
    if (FAILED(ret)) {
        return DI_SetError("Running the effect", ret);
    }

    return 0;
}


/*
 * Stops an effect.
 */
int
SDL_SYS_HapticStopEffect(SDL_Haptic * haptic, struct haptic_effect *effect)
{
    HRESULT ret;

    if (haptic->hwdata->bXInputHaptic) {
        XINPUT_VIBRATION vibration = { 0, 0 };
        SDL_LockMutex(haptic->hwdata->mutex);
        haptic->hwdata->stopTicks = 0;
        SDL_UnlockMutex(haptic->hwdata->mutex);
        return (XINPUTSETSTATE(haptic->hwdata->userid, &vibration) == ERROR_SUCCESS) ? 0 : -1;
    }

    ret = IDirectInputEffect_Stop(effect->hweffect->ref);
    if (FAILED(ret)) {
        return DI_SetError("Unable to stop effect", ret);
    }

    return 0;
}


/*
 * Frees the effect.
 */
void
SDL_SYS_HapticDestroyEffect(SDL_Haptic * haptic, struct haptic_effect *effect)
{
    HRESULT ret;

    if (haptic->hwdata->bXInputHaptic) {
        SDL_SYS_HapticStopEffect(haptic, effect);
    } else {
        ret = IDirectInputEffect_Unload(effect->hweffect->ref);
        if (FAILED(ret)) {
            DI_SetError("Removing effect from the device", ret);
        }
        SDL_SYS_HapticFreeDIEFFECT(&effect->hweffect->effect,
                                   effect->effect.type);
    }
    SDL_free(effect->hweffect);
    effect->hweffect = NULL;
}


/*
 * Gets the status of a haptic effect.
 */
int
SDL_SYS_HapticGetEffectStatus(SDL_Haptic * haptic,
                              struct haptic_effect *effect)
{
    HRESULT ret;
    DWORD status;

    ret = IDirectInputEffect_GetEffectStatus(effect->hweffect->ref, &status);
    if (FAILED(ret)) {
        return DI_SetError("Getting effect status", ret);
    }

    if (status == 0)
        return SDL_FALSE;
    return SDL_TRUE;
}


/*
 * Sets the gain.
 */
int
SDL_SYS_HapticSetGain(SDL_Haptic * haptic, int gain)
{
    HRESULT ret;
    DIPROPDWORD dipdw;

    /* Create the weird structure thingy. */
    dipdw.diph.dwSize = sizeof(DIPROPDWORD);
    dipdw.diph.dwHeaderSize = sizeof(DIPROPHEADER);
    dipdw.diph.dwObj = 0;
    dipdw.diph.dwHow = DIPH_DEVICE;
    dipdw.dwData = gain * 100;  /* 0 to 10,000 */

    /* Try to set the autocenter. */
    ret = IDirectInputDevice8_SetProperty(haptic->hwdata->device,
                                          DIPROP_FFGAIN, &dipdw.diph);
    if (FAILED(ret)) {
        return DI_SetError("Setting gain", ret);
    }

    return 0;
}


/*
 * Sets the autocentering.
 */
int
SDL_SYS_HapticSetAutocenter(SDL_Haptic * haptic, int autocenter)
{
    HRESULT ret;
    DIPROPDWORD dipdw;

    /* Create the weird structure thingy. */
    dipdw.diph.dwSize = sizeof(DIPROPDWORD);
    dipdw.diph.dwHeaderSize = sizeof(DIPROPHEADER);
    dipdw.diph.dwObj = 0;
    dipdw.diph.dwHow = DIPH_DEVICE;
    dipdw.dwData = (autocenter == 0) ? DIPROPAUTOCENTER_OFF :
        DIPROPAUTOCENTER_ON;

    /* Try to set the autocenter. */
    ret = IDirectInputDevice8_SetProperty(haptic->hwdata->device,
                                          DIPROP_AUTOCENTER, &dipdw.diph);
    if (FAILED(ret)) {
        return DI_SetError("Setting autocenter", ret);
    }

    return 0;
}


/*
 * Pauses the device.
 */
int
SDL_SYS_HapticPause(SDL_Haptic * haptic)
{
    HRESULT ret;

    /* Pause the device. */
    ret = IDirectInputDevice8_SendForceFeedbackCommand(haptic->hwdata->device,
                                                       DISFFC_PAUSE);
    if (FAILED(ret)) {
        return DI_SetError("Pausing the device", ret);
    }

    return 0;
}


/*
 * Pauses the device.
 */
int
SDL_SYS_HapticUnpause(SDL_Haptic * haptic)
{
    HRESULT ret;

    /* Unpause the device. */
    ret = IDirectInputDevice8_SendForceFeedbackCommand(haptic->hwdata->device,
                                                       DISFFC_CONTINUE);
    if (FAILED(ret)) {
        return DI_SetError("Pausing the device", ret);
    }

    return 0;
}


/*
 * Stops all the playing effects on the device.
 */
int
SDL_SYS_HapticStopAll(SDL_Haptic * haptic)
{
    HRESULT ret;

    if (haptic->hwdata->bXInputHaptic) {
        XINPUT_VIBRATION vibration = { 0, 0 };
        SDL_LockMutex(haptic->hwdata->mutex);
        haptic->hwdata->stopTicks = 0;
        SDL_UnlockMutex(haptic->hwdata->mutex);
        return (XINPUTSETSTATE(haptic->hwdata->userid, &vibration) == ERROR_SUCCESS) ? 0 : -1;
    }

    /* Try to stop the effects. */
    ret = IDirectInputDevice8_SendForceFeedbackCommand(haptic->hwdata->device,
                                                       DISFFC_STOPALL);
    if (FAILED(ret)) {
        return DI_SetError("Stopping the device", ret);
    }

    return 0;
}


/* !!! FIXME: this is a hack, remove this later. */
/* Since XInput doesn't offer a way to vibrate for X time, we hook into
 *  SDL_PumpEvents() to check if it's time to stop vibrating with some
 *  frequency.
 * In practice, this works for 99% of use cases. But in an ideal world,
 *  we do this in a separate thread so that:
 *    - we aren't bound to when the app chooses to pump the event queue.
 *    - we aren't adding more polling to the event queue
 *    - we can emulate all the haptic effects correctly (start on a delay,
 *      mix multiple effects, etc).
 *
 * Mostly, this is here to get rumbling to work, and all the other features
 *  are absent in the XInput path for now.  :(
 */
static int SDLCALL
SDL_RunXInputHaptic(void *arg)
{
    struct haptic_hwdata *hwdata = (struct haptic_hwdata *) arg;

    while (!hwdata->stopThread) {
        SDL_Delay(50);
        SDL_LockMutex(hwdata->mutex);
        /* If we're currently running and need to stop... */
        if (hwdata->stopTicks) {
            if ((hwdata->stopTicks != SDL_HAPTIC_INFINITY) && SDL_TICKS_PASSED(SDL_GetTicks(), hwdata->stopTicks)) {
                XINPUT_VIBRATION vibration = { 0, 0 };
                hwdata->stopTicks = 0;
                XINPUTSETSTATE(hwdata->userid, &vibration);
            }
        }
        SDL_UnlockMutex(hwdata->mutex);
    }

    return 0;
}

#endif /* SDL_HAPTIC_DINPUT */

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