goldberg_emulator/controller/gamepad.c
2020-01-19 01:34:52 -05:00

739 lines
20 KiB
C

/**
* Gamepad Input Library
* Sean Middleditch
* Copyright (C) 2010 Sean Middleditch
* LICENSE: MIT/X
*/
#include <math.h>
#include <string.h>
#include <errno.h>
#include <malloc.h>
#define GAMEPAD_EXPORT 1
#include "gamepad.h"
/* Platform-specific includes */
#if defined(_WIN32)
# define WIN32_LEAN_AND_MEAN 1
# undef UNICODE
# include "windows.h"
# include "xinput.h"
# pragma comment(lib, "XINPUT9_1_0.lib")
#elif defined(__linux__)
# include <linux/joystick.h>
# include <stdio.h>
# include <fcntl.h>
# include <unistd.h>
# include <dirent.h>
# include <sys/stat.h>
# include <time.h>
#else
# error "Unknown platform in gamepad.c"
#endif
#define BUTTON_TO_FLAG(b) (1 << (b))
/* Axis information */
typedef struct GAMEPAD_AXIS GAMEPAD_AXIS;
struct GAMEPAD_AXIS {
int x, y;
float nx, ny;
float length;
float angle;
GAMEPAD_STICKDIR dirLast, dirCurrent;
};
/* Trigger value information */
typedef struct GAMEPAD_TRIGINFO GAMEPAD_TRIGINFO;
struct GAMEPAD_TRIGINFO {
int value;
float length;
GAMEPAD_BOOL pressedLast, pressedCurrent;
};
/* Structure for state of a particular gamepad */
typedef struct GAMEPAD_STATE GAMEPAD_STATE;
struct GAMEPAD_STATE {
GAMEPAD_AXIS stick[STICK_COUNT];
GAMEPAD_TRIGINFO trigger[TRIGGER_COUNT];
int bLast, bCurrent, flags;
#if defined(__linux__)
char* device;
int fd;
int effect;
double axis_min[ABS_MAX];
double axis_max[ABS_MAX];
#endif
};
/* State of the four gamepads */
static GAMEPAD_STATE STATE[4];
/* Note whether a gamepad is currently connected */
#define FLAG_CONNECTED (1<<0)
#define FLAG_RUMBLE (1<<1)
/* Prototypes for utility functions */
static void GamepadResetState (GAMEPAD_DEVICE gamepad);
static void GamepadUpdateCommon (void);
static void GamepadUpdateDevice (GAMEPAD_DEVICE gamepad);
static void GamepadUpdateStick (GAMEPAD_AXIS* axis, float deadzone);
static void GamepadUpdateTrigger (GAMEPAD_TRIGINFO* trig);
/* Various values of PI */
#define PI_1_4 0.78539816339744f
#define PI_1_2 1.57079632679489f
#define PI_3_4 2.35619449019234f
#define PI 3.14159265358979f
/* Platform-specific implementation code */
#if defined(_WIN32)
void GamepadInit(void) {
int i;
for (i = 0; i != GAMEPAD_COUNT; ++i) {
STATE[i].flags = 0;
}
}
void GamepadUpdate(void) {
GamepadUpdateCommon();
}
static void GamepadUpdateDevice(GAMEPAD_DEVICE gamepad) {
XINPUT_STATE xs;
if (XInputGetState(gamepad, &xs) == 0) {
/* reset if the device was not already connected */
if ((STATE[gamepad].flags & FLAG_CONNECTED) == 0) {
GamepadResetState(gamepad);
}
/* mark that we are connected w/ rumble support */
STATE[gamepad].flags |= FLAG_CONNECTED|FLAG_RUMBLE;
/* update state */
STATE[gamepad].bCurrent = xs.Gamepad.wButtons;
STATE[gamepad].trigger[TRIGGER_LEFT].value = xs.Gamepad.bLeftTrigger;
STATE[gamepad].trigger[TRIGGER_RIGHT].value = xs.Gamepad.bRightTrigger;
STATE[gamepad].stick[STICK_LEFT].x = xs.Gamepad.sThumbLX;
STATE[gamepad].stick[STICK_LEFT].y = xs.Gamepad.sThumbLY;
STATE[gamepad].stick[STICK_RIGHT].x = xs.Gamepad.sThumbRX;
STATE[gamepad].stick[STICK_RIGHT].y = xs.Gamepad.sThumbRY;
} else {
/* disconnected */
STATE[gamepad].flags &= ~FLAG_CONNECTED;
}
}
void GamepadShutdown(void) {
/* no Win32 shutdown required */
}
void GamepadSetRumble(GAMEPAD_DEVICE gamepad, float left, float right, unsigned int rumble_length_ms) {
//TODO: rumble_length_ms
if ((STATE[gamepad].flags & FLAG_RUMBLE) != 0) {
XINPUT_VIBRATION vib;
ZeroMemory(&vib, sizeof(vib));
vib.wLeftMotorSpeed = (WORD)(left * 65535);
vib.wRightMotorSpeed = (WORD)(right * 65535);
XInputSetState(gamepad, &vib);
}
}
#elif defined(__linux__)
#define test_bit(nr, addr) \
(((1UL << ((nr) % (sizeof(long) * 8))) & ((addr)[(nr) / (sizeof(long) * 8)])) != 0)
#define NBITS(x) ((((x)-1)/(sizeof(long) * 8))+1)
static int IsGamepad(int fd, char *namebuf, const size_t namebuflen)
{
struct input_id inpid;
//uint16_t *guid16 = (uint16_t *)guid->data;
/* When udev is enabled we only get joystick devices here, so there's no need to test them */
unsigned long evbit[NBITS(EV_MAX)] = { 0 };
unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
unsigned long absbit[NBITS(ABS_MAX)] = { 0 };
if ((ioctl(fd, EVIOCGBIT(0, sizeof(evbit)), evbit) < 0) ||
(ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) < 0) ||
(ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) < 0)) {
return (0);
}
if (!(test_bit(EV_KEY, evbit) && test_bit(EV_ABS, evbit) &&
test_bit(ABS_X, absbit) && test_bit(ABS_Y, absbit))) {
return 0;
}
if (ioctl(fd, EVIOCGNAME(namebuflen), namebuf) < 0) {
return 0;
}
if (ioctl(fd, EVIOCGID, &inpid) < 0) {
return 0;
}
//printf("Joystick: %s, bustype = %d, vendor = 0x%.4x, product = 0x%.4x, version = %d\n", namebuf, inpid.bustype, inpid.vendor, inpid.product, inpid.version);
//memset(guid->data, 0, sizeof(guid->data));
/* We only need 16 bits for each of these; space them out to fill 128. */
/* Byteswap so devices get same GUID on little/big endian platforms. */
/*
*guid16++ = SDL_SwapLE16(inpid.bustype);
*guid16++ = 0;
if (inpid.vendor && inpid.product) {
*guid16++ = SDL_SwapLE16(inpid.vendor);
*guid16++ = 0;
*guid16++ = SDL_SwapLE16(inpid.product);
*guid16++ = 0;
*guid16++ = SDL_SwapLE16(inpid.version);
*guid16++ = 0;
} else {
strlcpy((char*)guid16, namebuf, sizeof(guid->data) - 4);
}
if (SDL_ShouldIgnoreJoystick(namebuf, *guid)) {
return 0;
}
*/
return 1;
}
static void GamepadAddDevice(const char* devPath);
static void GamepadRemoveDevice(const char* devPath);
static void GamepadDetect()
{
DIR *folder;
struct dirent *dent;
folder = opendir("/dev/input");
if (folder) {
while ((dent = readdir(folder))) {
int len = strlen(dent->d_name);
if (len > 5 && strncmp(dent->d_name, "event", 5) == 0) {
char path[PATH_MAX];
snprintf(path, sizeof(path), "/dev/input/%s", dent->d_name);
GamepadAddDevice(path);
}
}
closedir(folder);
}
for (int i = 0; i != GAMEPAD_COUNT; ++i) {
if ((STATE[i].flags & FLAG_CONNECTED) && STATE[i].device) {
struct stat sb;
//printf("%s\n", STATE[i].device);
if (stat(STATE[i].device, &sb) == -1) {
GamepadRemoveDevice(STATE[i].device);
}
}
}
}
/* Helper to add a new device */
static void GamepadAddDevice(const char* devPath) {
int i;
/* try to find a free controller */
for (i = 0; i != GAMEPAD_COUNT; ++i) {
if ((STATE[i].flags & FLAG_CONNECTED) == 0) {
break;
}
if (STATE[i].device && strcmp(devPath, STATE[i].device) == 0) {
return;
}
}
if (i == GAMEPAD_COUNT) {
return;
}
int fd = open(devPath, O_RDWR, 0);
if (fd < 0) return;
char namebuf[128];
int is_gamepad = IsGamepad(fd, namebuf, sizeof (namebuf));
if (!is_gamepad) {
close(fd);
return;
}
/* copy the device path */
STATE[i].device = strdup(devPath);
if (STATE[i].device == NULL) {
return;
}
/* reset device state */
GamepadResetState((GAMEPAD_DEVICE)i);
fcntl(fd, F_SETFL, O_NONBLOCK);
STATE[i].fd = fd;
STATE[i].flags |= FLAG_CONNECTED;
int controller = i;
{
int i, t;
unsigned long keybit[NBITS(KEY_MAX)] = { 0 };
unsigned long absbit[NBITS(ABS_MAX)] = { 0 };
unsigned long relbit[NBITS(REL_MAX)] = { 0 };
unsigned long ffbit[NBITS(FF_MAX)] = { 0 };
/* See if this device uses the new unified event API */
if ((ioctl(fd, EVIOCGBIT(EV_KEY, sizeof(keybit)), keybit) >= 0) &&
(ioctl(fd, EVIOCGBIT(EV_ABS, sizeof(absbit)), absbit) >= 0) &&
(ioctl(fd, EVIOCGBIT(EV_REL, sizeof(relbit)), relbit) >= 0)) {
/* Get the number of buttons, axes, and other thingamajigs */
for (i = BTN_JOYSTICK; i < KEY_MAX; ++i) {
if (test_bit(i, keybit)) {
//printf("Joystick has button: 0x%x\n", i);
}
}
for (i = 0; i < BTN_JOYSTICK; ++i) {
if (test_bit(i, keybit)) {
//printf("Joystick has button: 0x%x\n", i);
}
}
for (i = 0; i < ABS_MAX; ++i) {
/* Skip hats */
if (i == ABS_HAT0X) {
i = ABS_HAT3Y;
continue;
}
if (test_bit(i, absbit)) {
struct input_absinfo absinfo;
if (ioctl(fd, EVIOCGABS(i), &absinfo) < 0) {
continue;
}
/*
printf("Joystick has absolute axis: 0x%.2x\n", i);
printf("Values = { %d, %d, %d, %d, %d }\n",
absinfo.value, absinfo.minimum, absinfo.maximum,
absinfo.fuzz, absinfo.flat);
*/
STATE[controller].axis_min[i] = absinfo.minimum;
STATE[controller].axis_max[i] = absinfo.maximum;
}
}
for (i = ABS_HAT0X; i <= ABS_HAT3Y; i += 2) {
if (test_bit(i, absbit) || test_bit(i + 1, absbit)) {
struct input_absinfo absinfo;
int hat_index = (i - ABS_HAT0X) / 2;
if (ioctl(fd, EVIOCGABS(i), &absinfo) < 0) {
continue;
}
/*
printf("Joystick has hat %d\n", hat_index);
printf("Values = { %d, %d, %d, %d, %d }\n",
absinfo.value, absinfo.minimum, absinfo.maximum,
absinfo.fuzz, absinfo.flat);
*/
//joystick->hwdata->hats_indices[joystick->nhats++] = hat_index;
}
}
if (test_bit(REL_X, relbit) || test_bit(REL_Y, relbit)) {
//++joystick->nballs;
}
}
if (ioctl(fd, EVIOCGBIT(EV_FF, sizeof(ffbit)), ffbit) >= 0) {
if (test_bit(FF_RUMBLE, ffbit)) {
STATE[controller].flags |= FLAG_RUMBLE;
}
if (test_bit(FF_SINE, ffbit)) {
//printf("sine\n");
}
}
}
}
/* Helper to remove a device */
static void GamepadRemoveDevice(const char* devPath) {
int i;
for (i = 0; i != GAMEPAD_COUNT; ++i) {
if (STATE[i].device != NULL && strcmp(STATE[i].device, devPath) == 0) {
if (STATE[i].fd != -1) {
close(STATE[i].fd);
STATE[i].fd = -1;
}
free(STATE[i].device);
STATE[i].device = 0;
STATE[i].flags = 0;
break;
}
}
}
void GamepadInit(void) {
struct udev_list_entry* devices;
struct udev_list_entry* item;
struct udev_enumerate* enu;
int i;
/* initialize connection state */
for (i = 0; i != GAMEPAD_COUNT; ++i) {
STATE[i].flags = 0;
STATE[i].fd = STATE[i].effect = -1;
}
GamepadDetect();
}
void GamepadUpdate(void) {
static unsigned long last = 0;
unsigned long cur = time(NULL);
if (last + 2 < cur) {
GamepadDetect();
last = cur;
}
GamepadUpdateCommon();
}
static int adjust_values_trigger(double min, double max, double value)
{
return (((value + (0 - min)) / (max - min)) * 255.0);
}
static int adjust_values_stick(double min, double max, double value)
{
return (((value + (0 - min)) / (max - min)) * (65535.0)) - 32768.0;
}
static void GamepadUpdateDevice(GAMEPAD_DEVICE gamepad) {
if (STATE[gamepad].flags & FLAG_CONNECTED) {
struct input_event events[32];
int i, len;
int code;
while ((len = read(STATE[gamepad].fd, events, (sizeof events))) > 0) {
len /= sizeof(events[0]);
for (i = 0; i < len; ++i) {
int button = 0;
code = events[i].code;
switch (events[i].type) {
case EV_KEY:
//printf("EV_KEY %i\n", code);
switch (code) {
case BTN_SOUTH: button = BUTTON_A; break;
case BTN_EAST: button = BUTTON_B; break;
case BTN_NORTH: button = BUTTON_X; break;
case BTN_WEST: button = BUTTON_Y; break;
case BTN_TL: button = BUTTON_LEFT_SHOULDER; break;
case BTN_TR: button = BUTTON_RIGHT_SHOULDER; break;
case BTN_SELECT: button = BUTTON_BACK; break;
case BTN_START: button = BUTTON_START; break;
case BTN_MODE: button = 0; break; /* XBOX button */
case BTN_THUMBL: button = BUTTON_LEFT_THUMB; break;
case BTN_THUMBR: button = BUTTON_RIGHT_THUMB; break;
default: button = 0; break;
}
if (events[i].value) {
STATE[gamepad].bCurrent |= BUTTON_TO_FLAG(button);
} else {
STATE[gamepad].bCurrent &= ~BUTTON_TO_FLAG(button);
}
break;
case EV_ABS:
switch (code) {
case ABS_HAT0X:
case ABS_HAT0Y:
case ABS_HAT1X:
case ABS_HAT1Y:
case ABS_HAT2X:
case ABS_HAT2Y:
case ABS_HAT3X:
case ABS_HAT3Y:
//code -= ABS_HAT0X;
//printf("ABS_HAT %i\n", code);
switch(code) {
case ABS_HAT0X:
if (events[i].value < 0) {
STATE[gamepad].bCurrent |= BUTTON_TO_FLAG(BUTTON_DPAD_LEFT);
STATE[gamepad].bCurrent &= ~BUTTON_TO_FLAG(BUTTON_DPAD_RIGHT);
} else if (events[i].value > 0) {
STATE[gamepad].bCurrent |= BUTTON_TO_FLAG(BUTTON_DPAD_RIGHT);
STATE[gamepad].bCurrent &= ~BUTTON_TO_FLAG(BUTTON_DPAD_LEFT);
} else {
STATE[gamepad].bCurrent &= ~BUTTON_TO_FLAG(BUTTON_DPAD_LEFT) & ~BUTTON_TO_FLAG(BUTTON_DPAD_RIGHT);
}
break;
case ABS_HAT0Y:
if (events[i].value < 0) {
STATE[gamepad].bCurrent |= BUTTON_TO_FLAG(BUTTON_DPAD_UP);
STATE[gamepad].bCurrent &= ~BUTTON_TO_FLAG(BUTTON_DPAD_DOWN);
} else if (events[i].value > 0) {
STATE[gamepad].bCurrent |= BUTTON_TO_FLAG(BUTTON_DPAD_DOWN);
STATE[gamepad].bCurrent &= ~BUTTON_TO_FLAG(BUTTON_DPAD_UP);
} else {
STATE[gamepad].bCurrent &= ~BUTTON_TO_FLAG(BUTTON_DPAD_UP) & ~BUTTON_TO_FLAG(BUTTON_DPAD_DOWN);
}
break;
}
break;
default:
//printf("EV_ABS %i %i\n", code, events[i].value);
if (code == ABS_Z || code == ABS_RZ) {
int value = adjust_values_trigger(STATE[gamepad].axis_min[code], STATE[gamepad].axis_max[code], events[i].value);
switch(code) {
case ABS_Z : STATE[gamepad].trigger[TRIGGER_LEFT].value = value; break;
case ABS_RZ: STATE[gamepad].trigger[TRIGGER_RIGHT].value = value; break;
}
} else {
int value = adjust_values_stick(STATE[gamepad].axis_min[code], STATE[gamepad].axis_max[code], events[i].value);
switch(code) {
case ABS_X : STATE[gamepad].stick[STICK_LEFT].x = value; break;
case ABS_Y : STATE[gamepad].stick[STICK_LEFT].y = -value; break;
case ABS_RX: STATE[gamepad].stick[STICK_RIGHT].x = value; break;
case ABS_RY: STATE[gamepad].stick[STICK_RIGHT].y = -value; break;
}
}
break;
}
break;
case EV_REL:
switch (code) {
case REL_X:
case REL_Y:
code -= REL_X;
//printf("EV_REL %i %i\n", code, events[i].value);
break;
default:
break;
}
break;
case EV_SYN:
switch (code) {
case SYN_DROPPED :
//printf("Event SYN_DROPPED detected\n");
break;
default:
break;
}
default:
break;
}
}
}
}
}
void GamepadShutdown(void) {
int i;
/* cleanup devices */
for (i = 0; i != GAMEPAD_COUNT; ++i) {
if (STATE[i].device != NULL) {
free(STATE[i].device);
}
if (STATE[i].fd != -1) {
close(STATE[i].fd);
}
}
}
void GamepadSetRumble(GAMEPAD_DEVICE gamepad, float left, float right, unsigned int rumble_length_ms) {
if (STATE[gamepad].fd != -1) {
struct input_event play;
struct ff_effect ff;
/* define an effect for this rumble setting */
ff.type = FF_RUMBLE;
ff.id = STATE[gamepad].effect;
ff.u.rumble.strong_magnitude = (unsigned short)(left * 65535);
ff.u.rumble.weak_magnitude = (unsigned short)(right * 65535);
ff.replay.length = rumble_length_ms;
ff.replay.delay = 0;
/* upload the effect */
if (ioctl(STATE[gamepad].fd, EVIOCSFF, &ff) != -1) {
STATE[gamepad].effect = ff.id;
}
/* play the effect */
play.type = EV_FF;
play.code = STATE[gamepad].effect;
play.value = 1;
write(STATE[gamepad].fd, (const void*)&play, sizeof(play));
}
}
#else /* !defined(_WIN32) && !defined(__linux__) */
# error "Unknown platform in gamepad.c"
#endif /* end of platform implementations */
GAMEPAD_BOOL GamepadIsConnected(GAMEPAD_DEVICE device) {
return (STATE[device].flags & FLAG_CONNECTED) != 0 ? GAMEPAD_TRUE : GAMEPAD_FALSE;
}
GAMEPAD_BOOL GamepadButtonDown(GAMEPAD_DEVICE device, GAMEPAD_BUTTON button) {
return (STATE[device].bCurrent & BUTTON_TO_FLAG(button)) != 0 ? GAMEPAD_TRUE : GAMEPAD_FALSE;
}
GAMEPAD_BOOL GamepadButtonTriggered(GAMEPAD_DEVICE device, GAMEPAD_BUTTON button) {
return ((STATE[device].bLast & BUTTON_TO_FLAG(button)) == 0 &&
(STATE[device].bCurrent & BUTTON_TO_FLAG(button)) != 0) ? GAMEPAD_TRUE : GAMEPAD_FALSE;
}
GAMEPAD_BOOL GamepadButtonReleased(GAMEPAD_DEVICE device, GAMEPAD_BUTTON button) {
return ((STATE[device].bCurrent & BUTTON_TO_FLAG(button)) == 0 &&
(STATE[device].bLast & BUTTON_TO_FLAG(button)) != 0) ? GAMEPAD_TRUE : GAMEPAD_FALSE;
}
int GamepadTriggerValue(GAMEPAD_DEVICE device, GAMEPAD_TRIGGER trigger) {
return STATE[device].trigger[trigger].value;
}
float GamepadTriggerLength(GAMEPAD_DEVICE device, GAMEPAD_TRIGGER trigger) {
return STATE[device].trigger[trigger].length;
}
GAMEPAD_BOOL GamepadTriggerDown(GAMEPAD_DEVICE device, GAMEPAD_TRIGGER trigger) {
return STATE[device].trigger[trigger].pressedCurrent;
}
GAMEPAD_BOOL GamepadTriggerTriggered(GAMEPAD_DEVICE device, GAMEPAD_TRIGGER trigger) {
return (STATE[device].trigger[trigger].pressedCurrent &&
!STATE[device].trigger[trigger].pressedLast) ? GAMEPAD_TRUE : GAMEPAD_FALSE;
}
GAMEPAD_BOOL GamepadTriggerReleased(GAMEPAD_DEVICE device, GAMEPAD_TRIGGER trigger) {
return (!STATE[device].trigger[trigger].pressedCurrent &&
STATE[device].trigger[trigger].pressedLast) ? GAMEPAD_TRUE : GAMEPAD_FALSE;
}
void GamepadStickXY(GAMEPAD_DEVICE device, GAMEPAD_STICK stick, int *outX, int *outY) {
*outX = STATE[device].stick[stick].x;
*outY = STATE[device].stick[stick].y;
}
float GamepadStickLength(GAMEPAD_DEVICE device, GAMEPAD_STICK stick) {
return STATE[device].stick[stick].length;
}
void GamepadStickNormXY(GAMEPAD_DEVICE device, GAMEPAD_STICK stick, float *outX, float *outY) {
*outX = STATE[device].stick[stick].nx;
*outY = STATE[device].stick[stick].ny;
}
float GamepadStickAngle(GAMEPAD_DEVICE device, GAMEPAD_STICK stick) {
return STATE[device].stick[stick].angle;
}
GAMEPAD_STICKDIR GamepadStickDir(GAMEPAD_DEVICE device, GAMEPAD_STICK stick) {
return STATE[device].stick[stick].dirCurrent;
}
GAMEPAD_BOOL GamepadStickDirTriggered(GAMEPAD_DEVICE device, GAMEPAD_STICK stick, GAMEPAD_STICKDIR dir) {
return (STATE[device].stick[stick].dirCurrent == dir &&
STATE[device].stick[stick].dirCurrent != STATE[device].stick[stick].dirLast) ? GAMEPAD_TRUE : GAMEPAD_FALSE;
}
/* initialize common gamepad state */
static void GamepadResetState(GAMEPAD_DEVICE gamepad) {
memset(STATE[gamepad].stick, 0, sizeof(STATE[gamepad].stick));
memset(STATE[gamepad].trigger, 0, sizeof(STATE[gamepad].trigger));
STATE[gamepad].bLast = STATE[gamepad].bCurrent = 0;
}
/* Update individual sticks */
static void GamepadUpdateCommon(void) {
int i;
for (i = 0; i != GAMEPAD_COUNT; ++i) {
/* store previous button state */
STATE[i].bLast = STATE[i].bCurrent;
/* per-platform update routines */
GamepadUpdateDevice((GAMEPAD_DEVICE)i);
/* calculate refined stick and trigger values */
if ((STATE[i].flags & FLAG_CONNECTED) != 0) {
GamepadUpdateStick(&STATE[i].stick[STICK_LEFT], GAMEPAD_DEADZONE_LEFT_STICK);
GamepadUpdateStick(&STATE[i].stick[STICK_RIGHT], GAMEPAD_DEADZONE_RIGHT_STICK);
GamepadUpdateTrigger(&STATE[i].trigger[TRIGGER_LEFT]);
GamepadUpdateTrigger(&STATE[i].trigger[TRIGGER_RIGHT]);
}
}
}
/* Update stick info */
static void GamepadUpdateStick(GAMEPAD_AXIS* axis, float deadzone) {
// determine magnitude of stick
axis->length = sqrtf((float)(axis->x*axis->x) + (float)(axis->y*axis->y));
if (axis->length > deadzone) {
// clamp length to maximum value
if (axis->length > 32767.0f) {
axis->length = 32767.0f;
}
// normalized X and Y values
axis->nx = axis->x / axis->length;
axis->ny = axis->y / axis->length;
//fix special case
if (axis->nx < -1.0) axis->nx = -1.0;
if (axis->ny < -1.0) axis->ny = -1.0;
// adjust length for deadzone and find normalized length
axis->length -= deadzone;
axis->length /= (32767.0f - deadzone);
// find angle of stick in radians
axis->angle = atan2f((float)axis->y, (float)axis->x);
} else {
axis->x = axis->y = 0;
axis->nx = axis->ny = 0.0f;
axis->length = axis->angle = 0.0f;
}
/* update the stick direction */
axis->dirLast = axis->dirCurrent;
axis->dirCurrent = STICKDIR_CENTER;
/* check direction to see if it's non-centered */
if (axis->length != 0.f) {
if (axis->angle >= PI_1_4 && axis->angle < PI_3_4) {
axis->dirCurrent = STICKDIR_UP;
} else if (axis->angle >= -PI_3_4 && axis->angle < -PI_1_4) {
axis->dirCurrent = STICKDIR_DOWN;
} else if (axis->angle >= PI_3_4 || axis->angle < -PI_3_4) {
axis->dirCurrent = STICKDIR_LEFT;
} else /* if (axis->angle < PI_1_4 && axis->angle >= -PI_1_4) */ {
axis->dirCurrent = STICKDIR_RIGHT;
}
}
}
/* Update trigger info */
static void GamepadUpdateTrigger(GAMEPAD_TRIGINFO* trig) {
trig->pressedLast = trig->pressedCurrent;
if (trig->value > GAMEPAD_DEADZONE_TRIGGER) {
trig->length = ((trig->value - GAMEPAD_DEADZONE_TRIGGER) / (255.0f - GAMEPAD_DEADZONE_TRIGGER));
trig->pressedCurrent = GAMEPAD_TRUE;
} else {
trig->value = 0;
trig->length = 0.0f;
trig->pressedCurrent = GAMEPAD_FALSE;
}
}