Why is my player not moving in SpriteKit when tilting? - ios

Question

I am trying to using the option of tilting the screen to move my player. So i followed the instructions of Ray Wenderlich and his space invaders tutorial. I just can't seem to figure out why my player is not moving from left to right when tilting the screen.
Please have a look at it to help me out.
import SpriteKit
import CoreMotion
enum BodyType: UInt32 {
case player = 2
case enemy = 3
}
let motionManager = CMMotionManager()
class GameScene: SKScene, SKPhysicsContactDelegate {
let points = SKLabelNode(text: "0")
let gamePlayerSize = CGSize(width: 30, height: 16)
let gamePlayerName = "gameplayer"
override func didMove(to view: SKView) {
//SET UP FRAME
physicsBody = SKPhysicsBody(edgeLoopFrom: frame)
//SETTING UP Player
func setupPlayer() {
// 1
let player = makePlayer()
// 2
player.position = CGPoint(x: 240, y: 28)
addChild(player)
}
func makePlayer() -> SKNode {
let player = SKSpriteNode(imageNamed: "block")
player.name = gamePlayerName
// 1
player.physicsBody = SKPhysicsBody(rectangleOf: player.frame.size)
// 2
player.physicsBody!.isDynamic = true
// 3
player.physicsBody!.affectedByGravity = false
// 4
player.physicsBody!.mass = 0.02
return player
}
setupPlayer()
motionManager.startAccelerometerUpdates()
//score label
let points = SKLabelNode(text: "0")
points.position = CGPoint(x: 280, y: 510)
points.fontColor = UIColor.black
points.fontSize = 50
addChild(points)
// setting border around game
let borderBody = SKPhysicsBody(edgeLoopFrom: self.frame)
borderBody.friction = 0
self.physicsBody = borderBody
//ENEMY SETTINGS START
//repeat enemy spawning
run(SKAction.repeatForever(
SKAction.sequence([
SKAction.run(spawnEnemy),
SKAction.wait(forDuration: 1.0)])))
}
//Enemy settings
func random() -> CGFloat {
return CGFloat(Float(arc4random()) / 0xFFFFFFFF)
}
func random(min: CGFloat, max: CGFloat) -> CGFloat {
return random() * (max - min) + min
}
//spawn enemies
func spawnEnemy() {
// 2
let enemy = SKSpriteNode(imageNamed: "ball")
// 3
enemy.name = "enemy"
// 4
enemy.position = CGPoint(x: frame.size.width * random(min: 0, max: 1), y: frame.size.height + enemy.size.height/2)
// 5
addChild(enemy)
enemy.run(
SKAction.moveBy(x: 0.0 , y: -size.height - enemy.size.height,
duration: TimeInterval(random(min: 1, max: 2))))
//ENEMY SETTINGS END
func processUserMotion(forUpdate currentTime: CFTimeInterval) {
// 1
if let player = childNode(withName: gamePlayerName) as? SKSpriteNode {
// 2
if let data = motionManager.accelerometerData {
// 3
if fabs(data.acceleration.x) > 0.2 {
// 4 How do you move the ship?
player.physicsBody!.applyForce(CGVector(dx: 40 * CGFloat(data.acceleration.x), dy: 0))
}
}
}
}
func update(_ currentTime: TimeInterval) {
processUserMotion(forUpdate: currentTime)
}
} }

Answer 1

Have you nested your methods by accident? Looking at your code it seems so.
Did you check if the motion code is actually called?
Something like this should work
class GameScene: SKScene {
let motionManager = CMMotionManager()
override func didMove(to view: SKView) {
// setup player etc
motionManager.startAccelerometerUpdates()
}
func update(_ currentTime: TimeInterval) {
processUserMotion(forUpdate: currentTime)
}
}
Also as a tip, I would use optionals (?) when using your physics body instead of force unwrapping them (!). If it becomes nil at one point
you will crash when force unwrapping.
e.g
player.physicsBody?.affectedByGravity = false
Hope this helps