SDL/src/haptic/SDL_haptic.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2025 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"

#include "SDL_syshaptic.h"
#ifdef SDL_JOYSTICK_HIDAPI
#include "hidapi/SDL_hidapihaptic.h"
#endif
#include "SDL_haptic_c.h"
#include "../joystick/SDL_joystick_c.h" // For SDL_IsJoystickValid
#include "../SDL_hints_c.h"

typedef struct SDL_Haptic_VIDPID_Naxes {
    Uint16 vid;
    Uint16 pid;
    Uint16 naxes;
} SDL_Haptic_VIDPID_Naxes;

static void SDL_Haptic_Load_Axes_List(SDL_Haptic_VIDPID_Naxes **entries, int *num_entries)
{
    SDL_Haptic_VIDPID_Naxes entry;
    const char *spot;
    int length = 0;

    spot = SDL_GetHint(SDL_HINT_JOYSTICK_HAPTIC_AXES);
    if (!spot)
        return;

    while (SDL_sscanf(spot, "0x%hx/0x%hx/%hu%n", &entry.vid, &entry.pid, &entry.naxes, &length) == 3) {
        SDL_assert(length > 0);
        spot += length;
        length = 0;

        if ((*num_entries % 8) == 0) {
            int new_max = *num_entries + 8;
            SDL_Haptic_VIDPID_Naxes *new_entries =
                (SDL_Haptic_VIDPID_Naxes *)SDL_realloc(*entries, new_max * sizeof(**entries));

            // Out of memory, go with what we have already
            if (!new_entries)
                break;

            *entries = new_entries;
        }
        (*entries)[(*num_entries)++] = entry;

        if (spot[0] == ',')
            spot++;
    }
}

// /* Return -1 if not found */
static int SDL_Haptic_Naxes_List_Index(struct SDL_Haptic_VIDPID_Naxes *entries, int num_entries, Uint16 vid, Uint16 pid)
{
    if (!entries)
        return -1;

    int i;
    for (i = 0; i < num_entries; ++i) {
        if (entries[i].vid == vid && entries[i].pid == pid)
            return i;
    }

    return -1;
}

// Check if device needs a custom number of naxes
static int SDL_Haptic_Get_Naxes(Uint16 vid, Uint16 pid)
{
    int num_entries = 0, index = 0, naxes = -1;
    SDL_Haptic_VIDPID_Naxes *naxes_list = NULL;

    SDL_Haptic_Load_Axes_List(&naxes_list, &num_entries);
    if (!num_entries || !naxes_list)
        return -1;

    // Perform "wildcard" pass
    index = SDL_Haptic_Naxes_List_Index(naxes_list, num_entries, 0xffff, 0xffff);
    if (index >= 0)
        naxes = naxes_list[index].naxes;

    index = SDL_Haptic_Naxes_List_Index(naxes_list, num_entries, vid, pid);
    if (index >= 0)
        naxes = naxes_list[index].naxes;

    SDL_free(naxes_list);
    return naxes;
}

static SDL_Haptic *SDL_haptics = NULL;

#define CHECK_HAPTIC_MAGIC(haptic, result)                  \
    if (!SDL_ObjectValid(haptic, SDL_OBJECT_TYPE_HAPTIC)) { \
        SDL_InvalidParamError("haptic");                    \
        return result;                                      \
    }

bool SDL_InitHaptics(void)
{
    if (!SDL_SYS_HapticInit()) {
        return false;
    }
    #ifdef SDL_JOYSTICK_HIDAPI
    if (!SDL_HIDAPI_HapticInit()) {
        SDL_SYS_HapticQuit();
        return false;
    }
    #endif

    return true;
}

static bool SDL_GetHapticIndex(SDL_HapticID instance_id, int *driver_index)
{
    int num_haptics, device_index;

    if (instance_id > 0) {
        num_haptics = SDL_SYS_NumHaptics();
        for (device_index = 0; device_index < num_haptics; ++device_index) {
            SDL_HapticID haptic_id = SDL_SYS_HapticInstanceID(device_index);
            if (haptic_id == instance_id) {
                *driver_index = device_index;
                return true;
            }
        }
    }

    SDL_SetError("Haptic device %" SDL_PRIu32 " not found", instance_id);
    return false;
}

SDL_HapticID *SDL_GetHaptics(int *count)
{
    int device_index;
    int haptic_index = 0, num_haptics = 0;
    SDL_HapticID *haptics;

    num_haptics = SDL_SYS_NumHaptics();

    haptics = (SDL_HapticID *)SDL_malloc((num_haptics + 1) * sizeof(*haptics));
    if (haptics) {
        if (count) {
            *count = num_haptics;
        }

        for (device_index = 0; device_index < num_haptics; ++device_index) {
            haptics[haptic_index] = SDL_SYS_HapticInstanceID(device_index);
            SDL_assert(haptics[haptic_index] > 0);
            ++haptic_index;
        }
        haptics[haptic_index] = 0;
    } else {
        if (count) {
            *count = 0;
        }
    }

    return haptics;
}

const char *SDL_GetHapticNameForID(SDL_HapticID instance_id)
{
    int device_index;
    const char *name = NULL;

    if (SDL_GetHapticIndex(instance_id, &device_index)) {
        name = SDL_GetPersistentString(SDL_SYS_HapticName(device_index));
    }
    return name;
}

SDL_Haptic *SDL_OpenHaptic(SDL_HapticID instance_id)
{
    SDL_Haptic *haptic;
    SDL_Haptic *hapticlist;
    const char *name;
    int device_index = 0;

    if (!SDL_GetHapticIndex(instance_id, &device_index)) {
        return NULL;
    }

    hapticlist = SDL_haptics;
    /* If the haptic device is already open, return it
     * it is important that we have a single haptic device for each instance id
     */
    while (hapticlist) {
        if (instance_id == hapticlist->instance_id) {
            haptic = hapticlist;
            ++haptic->ref_count;
            return haptic;
        }
        hapticlist = hapticlist->next;
    }

    // Create the haptic device
    haptic = (SDL_Haptic *)SDL_calloc(1, sizeof(*haptic));
    if (!haptic) {
        return NULL;
    }

    // Initialize the haptic device
    haptic->instance_id = instance_id;
    haptic->rumble_id = -1;
    if (!SDL_SYS_HapticOpen(haptic)) {
        SDL_SetObjectValid(haptic, SDL_OBJECT_TYPE_HAPTIC, false);
        SDL_free(haptic);
        return NULL;
    }

    if (!haptic->name) {
        name = SDL_SYS_HapticName(device_index);
        if (name) {
            haptic->name = SDL_strdup(name);
        }
    }

    // Add haptic to list
    ++haptic->ref_count;
    // Link the haptic in the list
    haptic->next = SDL_haptics;
    SDL_haptics = haptic;

    SDL_SetObjectValid(haptic, SDL_OBJECT_TYPE_HAPTIC, true);

    // Disable autocenter and set gain to max.
    if (haptic->supported & SDL_HAPTIC_GAIN) {
        SDL_SetHapticGain(haptic, 100);
    }
    if (haptic->supported & SDL_HAPTIC_AUTOCENTER) {
        SDL_SetHapticAutocenter(haptic, 0);
    }

    return haptic;
}

SDL_Haptic *SDL_GetHapticFromID(SDL_HapticID instance_id)
{
    SDL_Haptic *haptic;

    for (haptic = SDL_haptics; haptic; haptic = haptic->next) {
        if (instance_id == haptic->instance_id) {
            break;
        }
    }
    return haptic;
}

SDL_HapticID SDL_GetHapticID(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, 0);

    return haptic->instance_id;
}

const char *SDL_GetHapticName(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, NULL);

    return SDL_GetPersistentString(haptic->name);
}

bool SDL_IsMouseHaptic(void)
{
    if (SDL_SYS_HapticMouse() < 0) {
        return false;
    }
    return true;
}

SDL_Haptic *SDL_OpenHapticFromMouse(void)
{
    int device_index;

    device_index = SDL_SYS_HapticMouse();

    if (device_index < 0) {
        SDL_SetError("Haptic: Mouse isn't a haptic device.");
        return NULL;
    }

    return SDL_OpenHaptic(device_index);
}

bool SDL_IsJoystickHaptic(SDL_Joystick *joystick)
{
    bool result = false;

    SDL_LockJoysticks();
    {
        // Must be a valid joystick
        if (SDL_IsJoystickValid(joystick) &&
            !SDL_IsGamepad(SDL_GetJoystickID(joystick))) {
            #ifdef SDL_JOYSTICK_HIDAPI
            result = SDL_SYS_JoystickIsHaptic(joystick) || SDL_HIDAPI_JoystickIsHaptic(joystick);
            #else
            result = SDL_SYS_JoystickIsHaptic(joystick);
            #endif
        }
    }
    SDL_UnlockJoysticks();

    return result;
}

SDL_Haptic *SDL_OpenHapticFromJoystick(SDL_Joystick *joystick)
{
    SDL_Haptic *haptic;
    SDL_Haptic *hapticlist;

    SDL_LockJoysticks();
    {
        // Joystick must be valid and haptic
        if (!SDL_IsJoystickHaptic(joystick)) {
            SDL_SetError("Haptic: Joystick isn't a haptic device.");
            SDL_UnlockJoysticks();
            return NULL;
        }

        hapticlist = SDL_haptics;
        // Check to see if joystick's haptic is already open
        while (hapticlist) {
            #ifdef SDL_JOYSTICK_HIDAPI
            if (SDL_SYS_JoystickSameHaptic(hapticlist, joystick) || SDL_HIDAPI_JoystickSameHaptic(hapticlist, joystick)) {
            #else
            if (SDL_SYS_JoystickSameHaptic(hapticlist, joystick)) {
            #endif
                haptic = hapticlist;
                ++haptic->ref_count;
                SDL_UnlockJoysticks();
                return haptic;
            }
            hapticlist = hapticlist->next;
        }

        // Create the haptic device
        haptic = (SDL_Haptic *)SDL_calloc(1, sizeof(*haptic));
        if (!haptic) {
            SDL_UnlockJoysticks();
            return NULL;
        }

        /* Initialize the haptic device
         * This function should fill in the instance ID and name.
         */
        SDL_SetObjectValid(haptic, SDL_OBJECT_TYPE_HAPTIC, true);
        haptic->rumble_id = -1;
        #ifdef SDL_JOYSTICK_HIDAPI
        if (SDL_HIDAPI_JoystickIsHaptic(joystick)) {
            if (!SDL_HIDAPI_HapticOpenFromJoystick(haptic, joystick)) {
                SDL_SetError("Haptic: SDL_HIDAPI_HapticOpenFromJoystick failed.");
                SDL_free(haptic);
                SDL_UnlockJoysticks();
                return NULL;
            }
        } else
        #endif
        if (!SDL_SYS_HapticOpenFromJoystick(haptic, joystick)) {
            SDL_SetError("Haptic: SDL_SYS_HapticOpenFromJoystick failed.");
            SDL_SetObjectValid(haptic, SDL_OBJECT_TYPE_HAPTIC, false);
            SDL_free(haptic);
            SDL_UnlockJoysticks();
            return NULL;
        }
        SDL_assert(haptic->instance_id != 0);
    }
    SDL_UnlockJoysticks();

    // Check if custom number of haptic axes was defined
    Uint16 vid = SDL_GetJoystickVendor(joystick);
    Uint16 pid = SDL_GetJoystickProduct(joystick);
    int general_axes = SDL_GetNumJoystickAxes(joystick);

    int naxes = SDL_Haptic_Get_Naxes(vid, pid);
    if (naxes > 0)
        haptic->naxes = naxes;

    // Limit to the actual number of axes found on the device
    if (general_axes >= 0 && naxes > general_axes)
        haptic->naxes = general_axes;

    // Add haptic to list
    ++haptic->ref_count;
    // Link the haptic in the list
    haptic->next = SDL_haptics;
    SDL_haptics = haptic;

    SDL_SetObjectValid(haptic, SDL_OBJECT_TYPE_HAPTIC, true);

    // Disable autocenter and set gain to max.
    if (haptic->supported & SDL_HAPTIC_GAIN) {
        SDL_SetHapticGain(haptic, 100);
    }
    if (haptic->supported & SDL_HAPTIC_AUTOCENTER) {
        SDL_SetHapticAutocenter(haptic, 0);
    }

    return haptic;
}

void SDL_CloseHaptic(SDL_Haptic *haptic)
{
    SDL_HapticEffectID i;
    SDL_Haptic *hapticlist;
    SDL_Haptic *hapticlistprev;

    CHECK_HAPTIC_MAGIC(haptic,);

    // Check if it's still in use
    if (--haptic->ref_count > 0) {
        return;
    }

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        SDL_HIDAPI_HapticClose(haptic);
    } else
    #endif
    {
        // Close it, properly removing effects if needed
        for (i = 0; i < haptic->neffects; i++) {
            if (haptic->effects[i].hweffect != NULL) {
                SDL_DestroyHapticEffect(haptic, i);
            }
        }
        SDL_SYS_HapticClose(haptic);
    }
    SDL_SetObjectValid(haptic, SDL_OBJECT_TYPE_HAPTIC, false);

    // Remove from the list
    hapticlist = SDL_haptics;
    hapticlistprev = NULL;
    while (hapticlist) {
        if (haptic == hapticlist) {
            if (hapticlistprev) {
                // unlink this entry
                hapticlistprev->next = hapticlist->next;
            } else {
                SDL_haptics = haptic->next;
            }

            break;
        }
        hapticlistprev = hapticlist;
        hapticlist = hapticlist->next;
    }

    // Free the data associated with this device
    SDL_free(haptic->name);
    SDL_free(haptic);
}

void SDL_QuitHaptics(void)
{
    while (SDL_haptics) {
        SDL_CloseHaptic(SDL_haptics);
    }

    #ifdef SDL_JOYSTICK_HIDAPI
    SDL_HIDAPI_HapticQuit();
    #endif
    SDL_SYS_HapticQuit();
}

int SDL_GetMaxHapticEffects(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, -1);

    return haptic->neffects;
}

int SDL_GetMaxHapticEffectsPlaying(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, -1);

    return haptic->nplaying;
}

Uint32 SDL_GetHapticFeatures(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, 0);

    return haptic->supported;
}

int SDL_GetNumHapticAxes(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, -1);

    return haptic->naxes;
}

bool SDL_HapticEffectSupported(SDL_Haptic *haptic, const SDL_HapticEffect *effect)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    if (!effect) {
        return false;
    }

    if ((haptic->supported & effect->type) != 0) {
        return true;
    }
    return false;
}

SDL_HapticEffectID SDL_CreateHapticEffect(SDL_Haptic *haptic, const SDL_HapticEffect *effect)
{
    SDL_HapticEffectID i;

    CHECK_HAPTIC_MAGIC(haptic, -1);

    if (!effect) {
        SDL_InvalidParamError("effect");
        return -1;
    }

    // Check to see if effect is supported
    if (SDL_HapticEffectSupported(haptic, effect) == false) {
        SDL_SetError("Haptic: Effect not supported by haptic device.");
        return -1;
    }

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticNewEffect(haptic, effect);
    }
    #endif

    // See if there's a free slot
    for (i = 0; i < haptic->neffects; i++) {
        if (haptic->effects[i].hweffect == NULL) {

            // Now let the backend create the real effect
            if (!SDL_SYS_HapticNewEffect(haptic, &haptic->effects[i], effect)) {
                return -1; // Backend failed to create effect
            }

            SDL_memcpy(&haptic->effects[i].effect, effect,
                       sizeof(SDL_HapticEffect));
            return i;
        }
    }

    SDL_SetError("Haptic: Device has no free space left.");
    return -1;
}

static bool ValidEffect(SDL_Haptic *haptic, SDL_HapticEffectID effect)
{
    if ((effect < 0) || (effect >= haptic->neffects)) {
        SDL_SetError("Haptic: Invalid effect identifier.");
        return false;
    }
    return true;
}

bool SDL_UpdateHapticEffect(SDL_Haptic *haptic, SDL_HapticEffectID effect, const SDL_HapticEffect *data)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticUpdateEffect(haptic, effect, data);
    }
    #endif

    if (!ValidEffect(haptic, effect)) {
        return false;
    }

    if (!data) {
        return SDL_InvalidParamError("data");
    }

    // Can't change type dynamically.
    if (data->type != haptic->effects[effect].effect.type) {
        return SDL_SetError("Haptic: Updating effect type is illegal.");
    }

    // Updates the effect
    if (!SDL_SYS_HapticUpdateEffect(haptic, &haptic->effects[effect], data)) {
        return false;
    }

    SDL_memcpy(&haptic->effects[effect].effect, data,
               sizeof(SDL_HapticEffect));
    return true;
}

bool SDL_RunHapticEffect(SDL_Haptic *haptic, SDL_HapticEffectID effect, Uint32 iterations)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticRunEffect(haptic, effect, iterations);
    }
    #endif

    if (!ValidEffect(haptic, effect)) {
        return false;
    }

    // Run the effect
    if (!SDL_SYS_HapticRunEffect(haptic, &haptic->effects[effect], iterations)) {
        return false;
    }

    return true;
}

bool SDL_StopHapticEffect(SDL_Haptic *haptic, SDL_HapticEffectID effect)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticStopEffect(haptic, effect);
    }
    #endif

    if (!ValidEffect(haptic, effect)) {
        return false;
    }

    // Stop the effect
    if (!SDL_SYS_HapticStopEffect(haptic, &haptic->effects[effect])) {
        return false;
    }

    return true;
}

void SDL_DestroyHapticEffect(SDL_Haptic *haptic, SDL_HapticEffectID effect)
{
    CHECK_HAPTIC_MAGIC(haptic,);

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        SDL_HIDAPI_HapticDestroyEffect(haptic, effect);
        return;
    }
    #endif

    if (!ValidEffect(haptic, effect)) {
        return;
    }

    // Not allocated
    if (haptic->effects[effect].hweffect == NULL) {
        return;
    }

    SDL_SYS_HapticDestroyEffect(haptic, &haptic->effects[effect]);
}

bool SDL_GetHapticEffectStatus(SDL_Haptic *haptic, SDL_HapticEffectID effect)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticGetEffectStatus(haptic, effect);
    }
    #endif

    if (!ValidEffect(haptic, effect)) {
        return false;
    }

    if (!(haptic->supported & SDL_HAPTIC_STATUS)) {
        return SDL_SetError("Haptic: Device does not support status queries.");
    }

    SDL_ClearError();

    return (SDL_SYS_HapticGetEffectStatus(haptic, &haptic->effects[effect]) > 0);
}

bool SDL_SetHapticGain(SDL_Haptic *haptic, int gain)
{
    const char *env;
    int real_gain, max_gain;

    CHECK_HAPTIC_MAGIC(haptic, false);

    if (!(haptic->supported & SDL_HAPTIC_GAIN)) {
        return SDL_SetError("Haptic: Device does not support setting gain.");
    }

    if ((gain < 0) || (gain > 100)) {
        return SDL_SetError("Haptic: Gain must be between 0 and 100.");
    }

    // The user can use an environment variable to override the max gain.
    env = SDL_getenv("SDL_HAPTIC_GAIN_MAX");
    if (env) {
        max_gain = SDL_atoi(env);

        // Check for sanity.
        if (max_gain < 0) {
            max_gain = 0;
        } else if (max_gain > 100) {
            max_gain = 100;
        }

        // We'll scale it linearly with SDL_HAPTIC_GAIN_MAX
        real_gain = (gain * max_gain) / 100;
    } else {
        real_gain = gain;
    }

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticSetGain(haptic, real_gain);
    }
    #endif

    return SDL_SYS_HapticSetGain(haptic, real_gain);
}

bool SDL_SetHapticAutocenter(SDL_Haptic *haptic, int autocenter)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    if (!(haptic->supported & SDL_HAPTIC_AUTOCENTER)) {
        return SDL_SetError("Haptic: Device does not support setting autocenter.");
    }

    if ((autocenter < 0) || (autocenter > 100)) {
        return SDL_SetError("Haptic: Autocenter must be between 0 and 100.");
    }

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticSetAutocenter(haptic, autocenter);
    }
    #endif

    return SDL_SYS_HapticSetAutocenter(haptic, autocenter);
}

bool SDL_PauseHaptic(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    if (!(haptic->supported & SDL_HAPTIC_PAUSE)) {
        return SDL_SetError("Haptic: Device does not support setting pausing.");
    }

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticPause(haptic);
    }
    #endif

    return SDL_SYS_HapticPause(haptic);
}

bool SDL_ResumeHaptic(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    if (!(haptic->supported & SDL_HAPTIC_PAUSE)) {
        return true; // Not going to be paused, so we pretend it's unpaused.
    }

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticResume(haptic);
    }
    #endif

    return SDL_SYS_HapticResume(haptic);
}

bool SDL_StopHapticEffects(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    #ifdef SDL_JOYSTICK_HIDAPI
    if (SDL_HIDAPI_HapticIsHidapi(haptic)) {
        return SDL_HIDAPI_HapticStopAll(haptic);
    }
    #endif

    return SDL_SYS_HapticStopAll(haptic);
}

bool SDL_HapticRumbleSupported(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    // Most things can use SINE, but XInput only has LEFTRIGHT.
    return (haptic->supported & (SDL_HAPTIC_SINE | SDL_HAPTIC_LEFTRIGHT)) != 0;
}

bool SDL_InitHapticRumble(SDL_Haptic *haptic)
{
    SDL_HapticEffect *efx = &haptic->rumble_effect;

    CHECK_HAPTIC_MAGIC(haptic, false);

    // Already allocated.
    if (haptic->rumble_id >= 0) {
        return true;
    }

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

    haptic->rumble_id = SDL_CreateHapticEffect(haptic, &haptic->rumble_effect);
    if (haptic->rumble_id >= 0) {
        return true;
    }
    return false;
}

bool SDL_PlayHapticRumble(SDL_Haptic *haptic, float strength, Uint32 length)
{
    SDL_HapticEffect *efx;
    Sint16 magnitude;

    CHECK_HAPTIC_MAGIC(haptic, false);

    if (haptic->rumble_id < 0) {
        return SDL_SetError("Haptic: Rumble effect not initialized on haptic device");
    }

    // Clamp strength.
    if (strength > 1.0f) {
        strength = 1.0f;
    } else if (strength < 0.0f) {
        strength = 0.0f;
    }
    magnitude = (Sint16)(32767.0f * strength);

    efx = &haptic->rumble_effect;
    if (efx->type == SDL_HAPTIC_SINE) {
        efx->periodic.magnitude = magnitude;
        efx->periodic.length = length;
    } else if (efx->type == SDL_HAPTIC_LEFTRIGHT) {
        efx->leftright.small_magnitude = efx->leftright.large_magnitude = magnitude;
        efx->leftright.length = length;
    } else {
        SDL_assert(!"This should have been caught elsewhere");
    }

    if (!SDL_UpdateHapticEffect(haptic, haptic->rumble_id, &haptic->rumble_effect)) {
        return false;
    }

    return SDL_RunHapticEffect(haptic, haptic->rumble_id, 1);
}

bool SDL_StopHapticRumble(SDL_Haptic *haptic)
{
    CHECK_HAPTIC_MAGIC(haptic, false);

    if (haptic->rumble_id < 0) {
        return SDL_SetError("Haptic: Rumble effect not initialized on haptic device");
    }

    return SDL_StopHapticEffect(haptic, haptic->rumble_id);
}