elite-dangerous-control-panel-2.cpp

// Global variable to hold the flags from the game state.
#define NO_FLAGS 0
unsigned long currentFlags = NO_FLAGS;

// Each button press will last about 100ms.
#define BUTTON_HOLD_TIME 100

struct Toggleswitch {
  byte currState;            // State of the physical switch.
  byte lastState;            // Last known state of the physical switch.
  byte buttonState;          // Whether the joystick button is pressed.
  byte joyButton;            // Which joystick button the switch belongs to.
  unsigned long releaseTime; // The time after which to stop pressing the button.
  long flag;                 // The flag assigned to this switch.

  // Must have a default constructor in order to use these in an array.
  Toggleswitch() {}

  // Constructor supports an initial state.
  Toggleswitch(byte _state, byte _button, long _flag) {
    currState = _state;
    lastState = _state;
    buttonState = BUTTON_RELEASED;
    joyButton = _button;
    releaseTime = 0L;
    flag = _flag;
  }

  // Is the game in the same state as the switch?
  bool isInSync() {
    // Always treat as in sync if there's no flag info.
    if (currentFlags == NO_FLAGS) {
      return true;
    }

    bool buttonPressed = lastState == BUTTON_PRESSED;
    bool flagSet = currentFlags & flag;

    // Need to account for the rollover of the millis() value.
    // In that case this value will be huge, which is fine, as it
    // will just try to sync up a little early.
    unsigned long timeSinceReleased = abs(signed(releaseTime - millis()));

	// Always assume things are in sync for a while after the button is pressed
    // to give the game time to catch up.
    return timeSinceReleased < BUTTON_SYNC_TIME || buttonPressed == flagSet;
  }

  // This will be called periodically for the switch to take care of its own updates.
  void update() {
  	// If the switch is flipped, or the game comes out of sync, trigger a button press.
    if (currState != lastState || !isInSync()) {
      lastState = currState;
      buttonState = BUTTON_PRESSED;
      Joystick.button(joyButton, true);
      releaseTime = millis() + BUTTON_HOLD_TIME;
    }
    
    // If the button is pressed and it's time to release it, release it.
    else if (buttonState == BUTTON_PRESSED && millis() >= releaseTime) {
      buttonState = BUTTON_RELEASED;
      Joystick.button(joyButton, false);
    }
  }
};