I've been looking around for a way to add an offset to the way the accelerometer tracks movement of the player in my game. In my game, you control the player character by tilting the phone forwards and backwards. This is translated by the accelerometer to x and y coordinates on screen. unfortunately, this means in order to stop the character from constantly being at the bottom of the screen, you have to hold the phone flat. Which isn't very comfortable for players.
So I'm trying to implement a way that whatever the angle of the phone is at when they start a game session, that is the default angle and then the tilt is determined by the delta of that angle rather than the raw data which would be against 0,0 I guess...
here is my attempt at figuring it out:
func instantiateAcceleration() {
if motionManager.accelerometerAvailable{
let queue = NSOperationQueue()
motionManager.startAccelerometerUpdatesToQueue(queue) { data, error in
let currentX = self.player.position.x
let currentY = self.player.position.y
if(!self.hasCapturedOffset){
/* So the first time we enter this loop. we'll cature the offset */
self.offsetY = data!.acceleration.y;
self.offsetX = data!.acceleration.x;
print("captured offset : x - \(self.offsetX) y - \(self.offsetY)")
self.hasCapturedOffset = true;
}
/* x coords */
if data!.acceleration.y < (0 - self.offsetY) {
self.destX = currentX + CGFloat(data!.acceleration.y * 100)
}
else if data!.acceleration.y > (0 + self.offsetY) {
self.destX = currentX + CGFloat(data!.acceleration.y * 100)
}
/* y coords */
if data!.acceleration.x > (0.1 - self.offsetX){
self.destY = currentY - CGFloat(data!.acceleration.x * 100)
}
else if data!.acceleration.x < (0.1 + self.offsetX) {
self.destY = currentY - CGFloat(data!.acceleration.x * 100)
}
/* keep it in bounds */
if(self.destY > self.size.height){
self.destY = self.size.height;
}else if(self.destY < 0){
self.destY = 0;
}
if(self.destX > self.size.width){
self.destX = self.size.width;
}else if(self.destX < 0){
self.destX = 0;
}
}
} else {
print("Accelerometer is not available")
}
}
that above func is called on the viewDidLoad and the self.DestX, self.DestY are used for updating the player in the update method:
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
/* Accelerometer data */
let action = SKAction.moveTo(CGPoint(x:destX, y:destY), duration: 0.1)
self.player.runAction(action)
}
I would really like to learn how to do this properly, I'm aware there are definitely some maths behind this is that I'm not familiar with. If somebody could point me in the right direction, I would really appreciate it :)
