static SInt32
GetHIDScaledCalibratedState(recDevice * pDevice, recElement * pElement, SInt32 min, SInt32 max)
{
const float deviceScale = max - min;
const float readScale = pElement->maxReport - pElement->minReport;
const SInt32 value = GetHIDElementState(pDevice, pElement);
if (readScale == 0) {
return value; /* no scaling at all */
}
return ((value - pElement->minReport) * deviceScale / readScale) + min;
}
static SDL_bool
GetHIDScaledCalibratedState(recDevice * pDevice, recElement * pElement, SInt32 min, SInt32 max, SInt32 *pValue)
{
const float deviceScale = max - min;
const float readScale = pElement->maxReport - pElement->minReport;
int returnValue = SDL_FALSE;
if (GetHIDElementState(pDevice, pElement, pValue))
{
if (readScale == 0) {
returnValue = SDL_TRUE; /* no scaling at all */
}
else
{
*pValue = ((*pValue - pElement->minReport) * deviceScale / readScale) + min;
returnValue = SDL_TRUE;
}
}
return returnValue;
}
/* 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
SDL_SYS_JoystickUpdate(SDL_Joystick * joystick)
{
recDevice *device = joystick->hwdata;
recElement *element;
SInt32 value, range;
int i;
if (!device) {
return;
}
if (device->removed) { /* device was unplugged; ignore it. */
joystick->closed = 1;
joystick->uncentered = 1;
joystick->hwdata = NULL;
return;
}
element = device->firstAxis;
i = 0;
while (element) {
value = GetHIDScaledCalibratedState(device, element, -32768, 32767);
if (value != joystick->axes[i]) {
SDL_PrivateJoystickAxis(joystick, i, value);
}
element = element->pNext;
++i;
}
element = device->firstButton;
i = 0;
while (element) {
value = GetHIDElementState(device, element);
if (value > 1) { /* handle pressure-sensitive buttons */
value = 1;
}
if (value != joystick->buttons[i]) {
SDL_PrivateJoystickButton(joystick, i, value);
}
element = element->pNext;
++i;
}
element = device->firstHat;
i = 0;
while (element) {
Uint8 pos = 0;
range = (element->max - element->min + 1);
value = GetHIDElementState(device, element) - element->min;
if (range == 4) { /* 4 position hatswitch - scale up value */
value *= 2;
} else if (range != 8) { /* Neither a 4 nor 8 positions - fall back to default position (centered) */
value = -1;
}
switch (value) {
case 0:
pos = SDL_HAT_UP;
break;
case 1:
pos = SDL_HAT_RIGHTUP;
break;
case 2:
pos = SDL_HAT_RIGHT;
break;
case 3:
pos = SDL_HAT_RIGHTDOWN;
break;
case 4:
pos = SDL_HAT_DOWN;
break;
case 5:
pos = SDL_HAT_LEFTDOWN;
break;
case 6:
pos = SDL_HAT_LEFT;
break;
case 7:
pos = SDL_HAT_LEFTUP;
break;
default:
/* Every other value is mapped to center. We do that because some
* joysticks use 8 and some 15 for this value, and apparently
* there are even more variants out there - so we try to be generous.
*/
pos = SDL_HAT_CENTERED;
break;
}
if (pos != joystick->hats[i]) {
SDL_PrivateJoystickHat(joystick, i, pos);
}
element = element->pNext;
++i;
}
}
