{

Sint16 initial_value; /* Initial axis state */

Sint16 value; /* Current axis state */

Sint16 zero; /* Zero point on the axis (-32768 for triggers) */

SDL_bool has_initial_value; /* Whether we've seen a value on the axis yet */

SDL_bool sent_initial_value; /* Whether we've sent the initial axis value */

{

SDL_JoystickID instance_id; /* Device instance, monotonically increasing from 0 */

char *name; /* Joystick name - system dependent */

SDL_JoystickGUID guid; /* Joystick guid */

int userid; /* XInput user index, if any */

int naxes; /* Number of axis controls on the joystick */

SDL_JoystickAxisInfo *axes;

int nhats; /* Number of hats on the joystick */

Uint8 *hats; /* Current hat states */

int nballs; /* Number of trackballs on the joystick */

struct balldelta {

int dx;

int dy;

} *balls; /* Current ball motion deltas */

int nbuttons; /* Number of buttons on the joystick */

Uint8 *buttons; /* Current button states */

SDL_bool attached;

SDL_bool is_game_controller;

SDL_bool delayed_guide_button; /* SDL_TRUE if this device has the guide button event delayed */

SDL_bool force_recentering; /* SDL_TRUE if this device needs to have its state reset to 0 */

SDL_JoystickPowerLevel epowerlevel; /* power level of this joystick, SDL_JOYSTICK_POWER_UNKNOWN if not supported */

struct _SDL_JoystickDriver *driver;

struct joystick_hwdata *hwdata; /* Driver dependent information */

int ref_count; /* Reference count for multiple opens */

struct _SDL_Joystick *next; /* pointer to next joystick we have allocated */

{

/* Function to scan the system for joysticks.

* Joystick 0 should be the system default joystick.

* This function should return 0, or -1 on an unrecoverable error.

*/

int (*Init)(void);

/* Function to return the number of joystick devices plugged in right now */

int (*GetCount)(void);

/* Function to cause any queued joystick insertions to be processed */

void (*Detect)(void);

/* Function to get the device-dependent name of a joystick */

const char *(*GetDeviceName)(int device_index);

/* Function to return the stable GUID for a plugged in device */

SDL_JoystickGUID (*GetDeviceGUID)(int device_index);

/* Function to get the current instance id of the joystick located at device_index */

SDL_JoystickID (*GetDeviceInstanceID)(int device_index);

/* Function to open a joystick for use.

The joystick to open is specified by the device index.

This should fill the nbuttons and naxes fields of the joystick structure.

It returns 0, or -1 if there is an error.

*/

int (*Open)(SDL_Joystick * joystick, int device_index);

/* Rumble functionality */

int (*Rumble)(SDL_Joystick * joystick, Uint16 low_frequency_rumble, Uint16 high_frequency_rumble, Uint32 duration_ms);

/* Function to update the state of a joystick - called as a device poll.

* This function shouldn't update the joystick structure directly,

* but instead should call SDL_PrivateJoystick*() to deliver events

* and update joystick device state.

*/

void (*Update)(SDL_Joystick * joystick);

/* Function to close a joystick after use */

void (*Close)(SDL_Joystick * joystick);

/* Function to perform any system-specific joystick related cleanup */

void (*Quit)(void);