src/haptic/darwin/SDL_syshaptic.c

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 2008 Edgar Simo

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#ifdef SDL_HAPTIC_IOKIT

#include "SDL_haptic.h"
#include "../SDL_syshaptic.h"
#include "SDL_joystick.h"
#include "../../joystick/SDL_sysjoystick.h"     /* For the real SDL_Joystick */
#include "../../joystick/darwin/SDL_sysjoystick_c.h"    /* For joystick hwdata */

#include <IOKit/IOKitLib.h>
#include <IOKit/hid/IOHIDKeys.h>
#include <IOKit/hid/IOHIDUsageTables.h>
#include <ForceFeedback/ForceFeedback.h>
#include <ForceFeedback/ForceFeedbackConstants.h>

#ifndef IO_OBJECT_NULL
#define IO_OBJECT_NULL	((io_service_t)0)
#endif

#define MAX_HAPTICS  32


/*
 * List of available haptic devices.
 */
static struct
{
    char name[256];             /* Name of the device. */

    io_service_t dev;           /* Node we use to create the device. */
    SDL_Haptic *haptic;         /* Haptic currently assosciated with it. */

    /* Usage pages for determining if it's a mouse or not. */
    long usage;
    long usagePage;
} SDL_hapticlist[MAX_HAPTICS];


/*
 * Haptic system hardware data.
 */
struct haptic_hwdata
{
    FFDeviceObjectReference device;     /* Hardware device. */
    UInt8 axes[3];
};


/*
 * Haptic system effect data.
 */
struct haptic_hweffect
{
    FFEffectObjectReference ref;        /* Reference. */
    struct FFEFFECT effect;     /* Hardware effect. */
};

/*
 * Prototypes.
 */
static void SDL_SYS_HapticFreeFFEFFECT(FFEFFECT * effect, int type);
static int HIDGetDeviceProduct(io_service_t dev, char *name);


/* 
 * Like strerror but for force feedback errors.
 */
static const char *
FFStrError(HRESULT err)
{
    switch (err) {
    case FFERR_DEVICEFULL:
        return "device full";
        /* This should be valid, but for some reason isn't defined... */
        /*case FFERR_DEVICENOTREG:
           return "device not registered"; */
    case FFERR_DEVICEPAUSED:
        return "device paused";
    case FFERR_DEVICERELEASED:
        return "device released";
    case FFERR_EFFECTPLAYING:
        return "effect playing";
    case FFERR_EFFECTTYPEMISMATCH:
        return "effect type mismatch";
    case FFERR_EFFECTTYPENOTSUPPORTED:
        return "effect type not supported";
    case FFERR_GENERIC:
        return "undetermined error";
    case FFERR_HASEFFECTS:
        return "device has effects";
    case FFERR_INCOMPLETEEFFECT:
        return "incomplete effect";
    case FFERR_INTERNAL:
        return "internal fault";
    case FFERR_INVALIDDOWNLOADID:
        return "invalid download id";
    case FFERR_INVALIDPARAM:
        return "invalid parameter";
    case FFERR_MOREDATA:
        return "more data";
    case FFERR_NOINTERFACE:
        return "interface not supported";
    case FFERR_NOTDOWNLOADED:
        return "effect is not downloaded";
    case FFERR_NOTINITIALIZED:
        return "object has not been initialized";
    case FFERR_OUTOFMEMORY:
        return "out of memory";
    case FFERR_UNPLUGGED:
        return "device is unplugged";
    case FFERR_UNSUPPORTED:
        return "function call unsupported";
    case FFERR_UNSUPPORTEDAXIS:
        return "axis unsupported";

    default:
        return "unknown error";
    }
}


/*
 * Initializes the haptic subsystem.
 */
int
SDL_SYS_HapticInit(void)
{
    int numhaptics;
    IOReturn result;
    io_iterator_t iter;
    CFDictionaryRef match;
    io_service_t device;
    CFMutableDictionaryRef hidProperties;
    CFTypeRef refCF;

    /* Clear all the memory. */
    SDL_memset(SDL_hapticlist, 0, sizeof(SDL_hapticlist));

    /* Get HID devices. */
    match = IOServiceMatching(kIOHIDDeviceKey);
    if (match == NULL) {
        SDL_SetError("Haptic: Failed to get IOServiceMatching.");
        return -1;
    }

    /* Now search I/O Registry for matching devices. */
    result = IOServiceGetMatchingServices(kIOMasterPortDefault, match, &iter);
    if (result != kIOReturnSuccess) {
        SDL_SetError("Haptic: Couldn't create a HID object iterator.");
        return -1;
    }
    /* IOServiceGetMatchingServices consumes dictionary. */

    if (!IOIteratorIsValid(iter)) {     /* No iterator. */
        numhaptics = 0;
        return 0;
    }

    numhaptics = 0;
    while ((device = IOIteratorNext(iter)) != IO_OBJECT_NULL) {

        /* Check for force feedback. */
        if (FFIsForceFeedback(device) == FF_OK) {

            /* Set basic device data. */
            HIDGetDeviceProduct(device, SDL_hapticlist[numhaptics].name);
            SDL_hapticlist[numhaptics].dev = device;
            SDL_hapticlist[numhaptics].haptic = NULL;

            /* Set usage pages. */
            hidProperties = 0;
            refCF = 0;
            result = IORegistryEntryCreateCFProperties(device,
                                                       &hidProperties,
                                                       kCFAllocatorDefault,
                                                       kNilOptions);
            if ((result == KERN_SUCCESS) && hidProperties) {
                refCF =
                    CFDictionaryGetValue(hidProperties,
                                         CFSTR(kIOHIDPrimaryUsagePageKey));
                if (refCF) {
                    if (!CFNumberGetValue(refCF, kCFNumberLongType,
                                          &SDL_hapticlist[numhaptics].
                                          usagePage))
                        SDL_SetError
                            ("Haptic: Recieving device's usage page.");
                    refCF =
                        CFDictionaryGetValue(hidProperties,
                                             CFSTR(kIOHIDPrimaryUsageKey));
                    if (refCF) {
                        if (!CFNumberGetValue(refCF, kCFNumberLongType,
                                              &SDL_hapticlist[numhaptics].
                                              usage))
                            SDL_SetError("Haptic: Recieving device's usage.");
                    }
                }
                CFRelease(hidProperties);
            }

            /* Device has been added. */
            numhaptics++;
        } else {                /* Free the unused device. */
            IOObjectRelease(device);
        }

        /* Reached haptic limit. */
        if (numhaptics >= MAX_HAPTICS)
            break;
    }
    IOObjectRelease(iter);

    return numhaptics;
}


/*
 * Return the name of a haptic device, does not need to be opened.
 */
const char *
SDL_SYS_HapticName(int index)
{
    return SDL_hapticlist[index].name;
}

/*
 * Gets the device's product name.
 */
static int
HIDGetDeviceProduct(io_service_t dev, char *name)
{
    CFMutableDictionaryRef hidProperties, usbProperties;
    io_registry_entry_t parent1, parent2;
    kern_return_t ret;

    hidProperties = usbProperties = 0;

    ret = IORegistryEntryCreateCFProperties(dev, &hidProperties,
                                            kCFAllocatorDefault, kNilOptions);
    if ((ret != KERN_SUCCESS) || !hidProperties) {
        SDL_SetError("Haptic: Unable to create CFProperties.");
        return -1;
    }

    /* Mac OS X currently is not mirroring all USB properties to HID page so need to look at USB device page also
     * get dictionary for usb properties: step up two levels and get CF dictionary for USB properties
     */
    if ((KERN_SUCCESS ==
         IORegistryEntryGetParentEntry(dev, kIOServicePlane, &parent1))
        && (KERN_SUCCESS ==
            IORegistryEntryGetParentEntry(parent1, kIOServicePlane, &parent2))
        && (KERN_SUCCESS ==
            IORegistryEntryCreateCFProperties(parent2, &usbProperties,
                                              kCFAllocatorDefault,
                                              kNilOptions))) {
        if (usbProperties) {
            CFTypeRef refCF = 0;
            /* get device info
             * try hid dictionary first, if fail then go to usb dictionary
             */


            /* Get product name */
            refCF =
                CFDictionaryGetValue(hidProperties, CFSTR(kIOHIDProductKey));
            if (!refCF)
                refCF =
                    CFDictionaryGetValue(usbProperties,
                                         CFSTR("USB Product Name"));
            if (refCF) {
                if (!CFStringGetCString(refCF, name, 256,
                                        CFStringGetSystemEncoding())) {
                    SDL_SetError
                        ("Haptic: CFStringGetCString error retrieving pDevice->product.");
                    return -1;
                }
            }

            CFRelease(usbProperties);
        } else {
            SDL_SetError
                ("Haptic: IORegistryEntryCreateCFProperties failed to create usbProperties.");
            return -1;
        }

        /* Release stuff. */
        if (kIOReturnSuccess != IOObjectRelease(parent2)) {
            SDL_SetError("Haptic: IOObjectRelease error with parent2.");
        }
        if (kIOReturnSuccess != IOObjectRelease(parent1)) {
            SDL_SetError("Haptic: IOObjectRelease error with parent1.");
        }
    } else {
        SDL_SetError("Haptic: Error getting registry entries.");
        return -1;
    }

    return 0;
}


#define FF_TEST(ff, s) \
if (features.supportedEffects & (ff)) supported |= (s)
/*
 * Gets supported features.
 */
static unsigned int
GetSupportedFeatures(SDL_Haptic * haptic)
{
    HRESULT ret;
    FFDeviceObjectReference device;
    FFCAPABILITIES features;
    unsigned int supported;
    Uint32 val;

    device = haptic->hwdata->device;

    ret = FFDeviceGetForceFeedbackCapabilities(device, &features);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Unable to get device's supported features.");
        return -1;
    }

    supported = 0;

    /* Get maximum effects. */
    haptic->neffects = features.storageCapacity;
    haptic->nplaying = features.playbackCapacity;

    /* Test for effects. */
    FF_TEST(FFCAP_ET_CONSTANTFORCE, SDL_HAPTIC_CONSTANT);
    FF_TEST(FFCAP_ET_RAMPFORCE, SDL_HAPTIC_RAMP);
    FF_TEST(FFCAP_ET_SQUARE, SDL_HAPTIC_SQUARE);
    FF_TEST(FFCAP_ET_SINE, SDL_HAPTIC_SINE);
    FF_TEST(FFCAP_ET_TRIANGLE, SDL_HAPTIC_TRIANGLE);
    FF_TEST(FFCAP_ET_SAWTOOTHUP, SDL_HAPTIC_SAWTOOTHUP);
    FF_TEST(FFCAP_ET_SAWTOOTHDOWN, SDL_HAPTIC_SAWTOOTHDOWN);
    FF_TEST(FFCAP_ET_SPRING, SDL_HAPTIC_SPRING);
    FF_TEST(FFCAP_ET_DAMPER, SDL_HAPTIC_DAMPER);
    FF_TEST(FFCAP_ET_INERTIA, SDL_HAPTIC_INERTIA);
    FF_TEST(FFCAP_ET_FRICTION, SDL_HAPTIC_FRICTION);
    FF_TEST(FFCAP_ET_CUSTOMFORCE, SDL_HAPTIC_CUSTOM);

    /* Check if supports gain. */
    ret = FFDeviceGetForceFeedbackProperty(device, FFPROP_FFGAIN,
                                           &val, sizeof(val));
    if (ret == FF_OK)
        supported |= SDL_HAPTIC_GAIN;
    else if (ret != FFERR_UNSUPPORTED) {
        SDL_SetError("Haptic: Unable to get if device supports gain: %s.",
                     FFStrError(ret));
        return -1;
    }

    /* Checks if supports autocenter. */
    ret = FFDeviceGetForceFeedbackProperty(device, FFPROP_AUTOCENTER,
                                           &val, sizeof(val));
    if (ret == FF_OK)
        supported |= SDL_HAPTIC_AUTOCENTER;
    else if (ret != FFERR_UNSUPPORTED) {
        SDL_SetError
            ("Haptic: Unable to get if device supports autocenter: %s.",
             FFStrError(ret));
        return -1;
    }

    /* Check for axes, we have an artificial limit on axes */
    haptic->naxes = ((features.numFfAxes) > 3) ? 3 : features.numFfAxes;
    /* Actually store the axes we want to use */
    SDL_memcpy(haptic->hwdata->axes, features.ffAxes,
               haptic->naxes * sizeof(Uint8));

    /* Always supported features. */
    supported |= SDL_HAPTIC_STATUS | SDL_HAPTIC_PAUSE;

    haptic->supported = supported;
    return 0;;
}


/*
 * Opens the haptic device from the file descriptor.
 */
static int
SDL_SYS_HapticOpenFromService(SDL_Haptic * haptic, io_service_t service)
{
    HRESULT ret;
    int ret2;

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

    /* Open the device */
    ret = FFCreateDevice(service, &haptic->hwdata->device);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Unable to create device from service: %s.",
                     FFStrError(ret));
        goto creat_err;
    }

    /* Get supported features. */
    ret2 = GetSupportedFeatures(haptic);
    if (haptic->supported < 0) {
        goto open_err;
    }


    /* Reset and then enable actuators. */
    ret = FFDeviceSendForceFeedbackCommand(haptic->hwdata->device,
                                           FFSFFC_RESET);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Unable to reset device: %s.", FFStrError(ret));
        goto open_err;
    }
    ret = FFDeviceSendForceFeedbackCommand(haptic->hwdata->device,
                                           FFSFFC_SETACTUATORSON);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Unable to enable actuators: %s.",
                     FFStrError(ret));
        goto open_err;
    }


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

    return 0;

    /* Error handling */
  open_err:
    FFReleaseDevice(haptic->hwdata->device);
  creat_err:
    if (haptic->hwdata != NULL) {
        free(haptic->hwdata);
        haptic->hwdata = NULL;
    }
    return -1;

}


/*
 * Opens a haptic device for usage.
 */
int
SDL_SYS_HapticOpen(SDL_Haptic * haptic)
{
    return SDL_SYS_HapticOpenFromService(haptic,
                                         SDL_hapticlist[haptic->index].dev);
}


/*
 * Opens a haptic device from first mouse it finds for usage.
 */
int
SDL_SYS_HapticMouse(void)
{
    int i;

    for (i = 0; i < SDL_numhaptics; i++) {
        if ((SDL_hapticlist[i].usagePage == kHIDPage_GenericDesktop) &&
            (SDL_hapticlist[i].usage == kHIDUsage_GD_Mouse))
            return i;
    }

    return -1;
}


/*
 * Checks to see if a joystick has haptic features.
 */
int
SDL_SYS_JoystickIsHaptic(SDL_Joystick * joystick)
{
    if (joystick->hwdata->ffservice != 0)
        return SDL_TRUE;
    return SDL_FALSE;
}


/*
 * Checks to see if the haptic device and joystick and in reality the same.
 */
int
SDL_SYS_JoystickSameHaptic(SDL_Haptic * haptic, SDL_Joystick * joystick)
{
    if (IOObjectIsEqualTo((io_object_t) haptic->hwdata->device,
                          joystick->hwdata->ffservice))
        return 1;
    return 0;
}


/*
 * Opens a SDL_Haptic from a SDL_Joystick.
 */
int
SDL_SYS_HapticOpenFromJoystick(SDL_Haptic * haptic, SDL_Joystick * joystick)
{
    return SDL_SYS_HapticOpenFromService(haptic, joystick->hwdata->ffservice);
}


/*
 * 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 */
        FFReleaseDevice(haptic->hwdata->device);

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


/* 
 * Clean up after system specific haptic stuff
 */
void
SDL_SYS_HapticQuit(void)
{
    int i;

    for (i = 0; i < SDL_numhaptics; i++) {
        /* Opened and not closed haptics are leaked, this is on purpose.
         * Close your haptic devices after usage. */

        /* Free the io_service_t */
        IOObjectRelease(SDL_hapticlist[i].dev);
    }
}


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

    dwTriggerButton = FFEB_NOTRIGGER;

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

    return dwTriggerButton;
}


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

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

    /* Has axes. */
    rglDir = SDL_malloc(sizeof(LONG) * naxes);
    if (rglDir == NULL) {
        SDL_OutOfMemory();
        return -1;
    }
    SDL_memset(rglDir, 0, sizeof(LONG) * naxes);
    effect->rglDirection = rglDir;

    switch (dir->type) {
    case SDL_HAPTIC_POLAR:
        effect->dwFlags |= FFEFF_POLAR;
        rglDir[0] = dir->dir[0];
        return 0;
    case SDL_HAPTIC_CARTESIAN:
        effect->dwFlags |= FFEFF_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 |= FFEFF_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:
        SDL_SetError("Haptic: Unknown direction type.");
        return -1;
    }
}


/* Clamps and converts. */
#define CCONVERT(x)   (((x) > 0x7FFF) ? 10000 : ((x)*10000) / 0x7FFF)
/* Just converts. */
#define CONVERT(x)    (((x)*10000) / 0x7FFF)
/*
 * Creates the FFEFFECT from a SDL_HapticEffect.
 */
static int
SDL_SYS_ToFFEFFECT(SDL_Haptic * haptic, FFEFFECT * dest,
                   SDL_HapticEffect * src)
{
    int i;
    FFCONSTANTFORCE *constant;
    FFPERIODIC *periodic;
    FFCONDITION *condition;     /* Actually an array of conditions - one per axis. */
    FFRAMPFORCE *ramp;
    FFCUSTOMFORCE *custom;
    FFENVELOPE *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(FFEFFECT));
    dest->dwSize = sizeof(FFEFFECT);    /* Set the structure size. */
    dest->dwSamplePeriod = 0;   /* Not used by us. */
    dest->dwGain = 10000;       /* Gain is set globally, not locally. */
    dest->dwFlags = FFEFF_OBJECTOFFSETS;        /* Seems obligatory. */

    /* Envelope. */
    envelope = SDL_malloc(sizeof(FFENVELOPE));
    if (envelope == NULL) {
        SDL_OutOfMemory();
        return -1;
    }
    SDL_memset(envelope, 0, sizeof(FFENVELOPE));
    dest->lpEnvelope = envelope;
    envelope->dwSize = sizeof(FFENVELOPE);      /* Always should be this. */

    /* Axes. */
    dest->cAxes = haptic->naxes;
    if (dest->cAxes > 0) {
        axes = SDL_malloc(sizeof(DWORD) * dest->cAxes);
        if (axes == NULL) {
            SDL_OutOfMemory();
            return -1;
        }
        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(FFCONSTANTFORCE));
        if (constant == NULL) {
            SDL_OutOfMemory();
            return -1;
        }
        SDL_memset(constant, 0, sizeof(FFCONSTANTFORCE));

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

        /* Generics */
        dest->dwDuration = hap_constant->length * 1000; /* In microseconds. */
        dest->dwTriggerButton = FFGetTriggerButton(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(envelope);
            dest->lpEnvelope = NULL;
        } else {
            envelope->dwAttackLevel = CCONVERT(hap_constant->attack_level);
            envelope->dwAttackTime = hap_constant->attack_length * 1000;
            envelope->dwFadeLevel = CCONVERT(hap_constant->fade_level);
            envelope->dwFadeTime = hap_constant->fade_length * 1000;
        }

        break;

    case SDL_HAPTIC_SINE:
    case SDL_HAPTIC_SQUARE:
    case SDL_HAPTIC_TRIANGLE:
    case SDL_HAPTIC_SAWTOOTHUP:
    case SDL_HAPTIC_SAWTOOTHDOWN:
        hap_periodic = &src->periodic;
        periodic = SDL_malloc(sizeof(FFPERIODIC));
        if (periodic == NULL) {
            SDL_OutOfMemory();
            return -1;
        }
        SDL_memset(periodic, 0, sizeof(FFPERIODIC));

        /* 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(FFPERIODIC);
        dest->lpvTypeSpecificParams = periodic;

        /* Generics */
        dest->dwDuration = hap_periodic->length * 1000; /* In microseconds. */
        dest->dwTriggerButton = FFGetTriggerButton(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(envelope);
            dest->lpEnvelope = NULL;
        } else {
            envelope->dwAttackLevel = CCONVERT(hap_periodic->attack_level);
            envelope->dwAttackTime = hap_periodic->attack_length * 1000;
            envelope->dwFadeLevel = CCONVERT(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(FFCONDITION) * dest->cAxes);
        if (condition == NULL) {
            SDL_OutOfMemory();
            return -1;
        }
        SDL_memset(condition, 0, sizeof(FFCONDITION));

        /* Specifics */
        for (i = 0; i < 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 =
                CCONVERT(hap_condition->right_sat[i]);
            condition[i].dwNegativeSaturation =
                CCONVERT(hap_condition->left_sat[i]);
            condition[i].lDeadBand = CCONVERT(hap_condition->deadband[i]);
        }
        dest->cbTypeSpecificParams = sizeof(FFCONDITION) * dest->cAxes;
        dest->lpvTypeSpecificParams = condition;

        /* Generics */
        dest->dwDuration = hap_condition->length * 1000;        /* In microseconds. */
        dest->dwTriggerButton = FFGetTriggerButton(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(FFRAMPFORCE));
        if (ramp == NULL) {
            SDL_OutOfMemory();
            return -1;
        }
        SDL_memset(ramp, 0, sizeof(FFRAMPFORCE));

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

        /* Generics */
        dest->dwDuration = hap_ramp->length * 1000;     /* In microseconds. */
        dest->dwTriggerButton = FFGetTriggerButton(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(envelope);
            dest->lpEnvelope = NULL;
        } else {
            envelope->dwAttackLevel = CCONVERT(hap_ramp->attack_level);
            envelope->dwAttackTime = hap_ramp->attack_length * 1000;
            envelope->dwFadeLevel = CCONVERT(hap_ramp->fade_level);
            envelope->dwFadeTime = hap_ramp->fade_length * 1000;
        }

        break;

    case SDL_HAPTIC_CUSTOM:
        hap_custom = &src->custom;
        custom = SDL_malloc(sizeof(FFCUSTOMFORCE));
        if (custom == NULL) {
            SDL_OutOfMemory();
            return -1;
        }
        SDL_memset(custom, 0, sizeof(FFCUSTOMFORCE));

        /* 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] = CCONVERT(hap_custom->data[i]);
        }
        dest->cbTypeSpecificParams = sizeof(FFCUSTOMFORCE);
        dest->lpvTypeSpecificParams = custom;

        /* Generics */
        dest->dwDuration = hap_custom->length * 1000;   /* In microseconds. */
        dest->dwTriggerButton = FFGetTriggerButton(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(envelope);
            dest->lpEnvelope = NULL;
        } else {
            envelope->dwAttackLevel = CCONVERT(hap_custom->attack_level);
            envelope->dwAttackTime = hap_custom->attack_length * 1000;
            envelope->dwFadeLevel = CCONVERT(hap_custom->fade_level);
            envelope->dwFadeTime = hap_custom->fade_length * 1000;
        }

        break;


    default:
        SDL_SetError("Haptic: Unknown effect type.");
        return -1;
    }

    return 0;
}


/*
 * Frees an FFEFFECT allocated by SDL_SYS_ToFFEFFECT.
 */
static void
SDL_SYS_HapticFreeFFEFFECT(FFEFFECT * effect, int type)
{
    FFCUSTOMFORCE *custom;

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


/*
 * Gets the effect type from the generic SDL haptic effect wrapper.
 */
CFUUIDRef
SDL_SYS_HapticEffectType(Uint16 type)
{
    switch (type) {
    case SDL_HAPTIC_CONSTANT:
        return kFFEffectType_ConstantForce_ID;

    case SDL_HAPTIC_RAMP:
        return kFFEffectType_RampForce_ID;

    case SDL_HAPTIC_SQUARE:
        return kFFEffectType_Square_ID;

    case SDL_HAPTIC_SINE:
        return kFFEffectType_Sine_ID;

    case SDL_HAPTIC_TRIANGLE:
        return kFFEffectType_Triangle_ID;

    case SDL_HAPTIC_SAWTOOTHUP:
        return kFFEffectType_SawtoothUp_ID;

    case SDL_HAPTIC_SAWTOOTHDOWN:
        return kFFEffectType_SawtoothDown_ID;

    case SDL_HAPTIC_SPRING:
        return kFFEffectType_Spring_ID;

    case SDL_HAPTIC_DAMPER:
        return kFFEffectType_Damper_ID;

    case SDL_HAPTIC_INERTIA:
        return kFFEffectType_Inertia_ID;

    case SDL_HAPTIC_FRICTION:
        return kFFEffectType_Friction_ID;

    case SDL_HAPTIC_CUSTOM:
        return kFFEffectType_CustomForce_ID;

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


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

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

    /* Get the type. */
    type = SDL_SYS_HapticEffectType(base->type);
    if (type == NULL) {
        goto err_hweffect;
    }

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

    /* Create the actual effect. */
    ret = FFDeviceCreateEffect(haptic->hwdata->device, type,
                               &effect->hweffect->effect,
                               &effect->hweffect->ref);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Unable to create effect: %s.", FFStrError(ret));
        goto err_effectdone;
    }

    return 0;

  err_effectdone:
    SDL_SYS_HapticFreeFFEFFECT(&effect->hweffect->effect, base->type);
  err_hweffect:
    if (effect->hweffect != NULL) {
        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;
    FFEffectParameterFlag flags;
    FFEFFECT temp;

    /* Get the effect. */
    SDL_memset(&temp, 0, sizeof(FFEFFECT));
    if (SDL_SYS_ToFFEFFECT(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 = FFEP_DIRECTION |
        FFEP_DURATION |
        FFEP_ENVELOPE |
        FFEP_STARTDELAY |
        FFEP_TRIGGERBUTTON |
        FFEP_TRIGGERREPEATINTERVAL | FFEP_TYPESPECIFICPARAMS;

    /* Create the actual effect. */
    ret = FFEffectSetParameters(effect->hweffect->ref, &temp, flags);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Unable to update effect: %s.", FFStrError(ret));
        goto err_update;
    }

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

    return 0;

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


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

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

    /* Run the effect. */
    ret = FFEffectStart(effect->hweffect->ref, iter, 0);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Unable to run the effect: %s.",
                     FFStrError(ret));
        return -1;
    }

    return 0;
}


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

    ret = FFEffectStop(effect->hweffect->ref);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Unable to stop the effect: %s.",
                     FFStrError(ret));
        return -1;
    }

    return 0;
}


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

    ret =
        FFDeviceReleaseEffect(haptic->hwdata->device, effect->hweffect->ref);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Error removing the effect from the device: %s.",
                     FFStrError(ret));
    }
    SDL_SYS_HapticFreeFFEFFECT(&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;
    FFEffectStatusFlag status;

    ret = FFEffectGetEffectStatus(effect->hweffect->ref, &status);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Unable to get effect status: %s.",
                     FFStrError(ret));
        return -1;
    }

    if (status == 0)
        return SDL_FALSE;
    return SDL_TRUE;            /* Assume it's playing or emulated. */
}


/*
 * Sets the gain.
 */
int
SDL_SYS_HapticSetGain(SDL_Haptic * haptic, int gain)
{
    HRESULT ret;
    Uint32 val;

    val = gain * 100;           /* Mac OS X uses 0 to 10,000 */
    ret =
        FFDeviceSetForceFeedbackProperty(haptic->hwdata->device,
                                         FFPROP_FFGAIN, &val);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Error setting gain: %s.", FFStrError(ret));
        return -1;
    }

    return 0;
}


/*
 * Sets the autocentering.
 */
int
SDL_SYS_HapticSetAutocenter(SDL_Haptic * haptic, int autocenter)
{
    HRESULT ret;
    Uint32 val;

    /* Mac OS X only has 0 (off) and 1 (on) */
    if (autocenter == 0)
        val = 0;
    else
        val = 1;

    ret = FFDeviceSetForceFeedbackProperty(haptic->hwdata->device,
                                           FFPROP_AUTOCENTER, &val);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Error setting autocenter: %s.",
                     FFStrError(ret));
        return -1;
    }

    return 0;
}


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

    ret = FFDeviceSendForceFeedbackCommand(haptic->hwdata->device,
                                           FFSFFC_PAUSE);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Error pausing device: %s.", FFStrError(ret));
        return -1;
    }

    return 0;
}


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

    ret = FFDeviceSendForceFeedbackCommand(haptic->hwdata->device,
                                           FFSFFC_CONTINUE);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Error pausing device: %s.", FFStrError(ret));
        return -1;
    }

    return 0;
}


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

    ret = FFDeviceSendForceFeedbackCommand(haptic->hwdata->device,
                                           FFSFFC_STOPALL);
    if (ret != FF_OK) {
        SDL_SetError("Haptic: Error stopping device: %s.", FFStrError(ret));
        return -1;
    }

    return 0;
}


#endif /* SDL_HAPTIC_IOKIT */