Keeping an Object from moving beyond a certain point - ios

Question

Im am making a game in sprite kit that requires the user to move the player across the x axis to catch things. I am trying to make it impossible for the player to move off the screen because that looks bad. I have tried to do this with an if statement saying if it moves past a certain point teleport it back to the correct point but am not sure how to do this. That might be the right way to do this but i'm not sure. Please tell / show me what I should do to make this work. I will post the code below.
import SpriteKit
struct physicsCatagory {
static let person : UInt32 = 0x1 << 1
static let Ice : UInt32 = 0x1 << 2
static let IceTwo : UInt32 = 0x1 << 3
static let IceThree : UInt32 = 0x1 << 4
static let Score : UInt32 = 0x1 << 5
}
class GameScene: SKScene, SKPhysicsContactDelegate {
var timeOfLastSpawn: CFTimeInterval = 0.0
var timePerSpawn: CFTimeInterval = 1.2
var scorenumber = Int()
var lifenumber = Int()
var SpeedNumber : Double = 0.5
var person = SKSpriteNode(imageNamed: "Person1")
let Score = SKSpriteNode()
var ScoreLable = SKLabelNode()
let BackGround = SKSpriteNode (imageNamed: "BackGround")
override func didMoveToView(view: SKView) {
self.scene?.backgroundColor = UIColor.blueColor()
physicsWorld.contactDelegate = self
self.scene?.size = CGSize(width: 640, height: 1136)
lifenumber = 0
SpeedNumber = 1
BackGround.size = CGSize(width: self.frame.width, height: self.frame.height)
BackGround.position = CGPointMake(self.size.width / 2, self.size.height / 2)
BackGround.zPosition = -5
self.addChild(BackGround)
Score.size = CGSize(width: 648, height: 1)
Score.position = CGPoint(x: 320, y: -90)
Score.physicsBody = SKPhysicsBody(rectangleOfSize: Score.size)
Score.physicsBody?.affectedByGravity = false
Score.physicsBody?.dynamic = false
Score.physicsBody?.categoryBitMask = physicsCatagory.Score
Score.physicsBody?.collisionBitMask = 0
Score.physicsBody?.contactTestBitMask = physicsCatagory.IceThree
Score.color = SKColor.blueColor()
self.addChild(Score)
person.zPosition = 1
person.position = CGPointMake(self.size.width/2, self.size.height/10)
person.setScale(0.32)
person.physicsBody = SKPhysicsBody (rectangleOfSize: CGSize(width: 40, height: 50))
person.physicsBody?.affectedByGravity = false
person.physicsBody?.categoryBitMask = physicsCatagory.person
person.physicsBody?.contactTestBitMask = physicsCatagory.Ice
person.physicsBody?.collisionBitMask = physicsCatagory.Ice
person.physicsBody?.dynamic = false
ScoreLable = SKLabelNode(fontNamed: "Zapfino")
ScoreLable.position = CGPoint(x: self.frame.width / 2, y: 1000)
ScoreLable.text = "\(scorenumber)"
ScoreLable.fontColor = UIColor.yellowColor()
ScoreLable.fontSize = 100
ScoreLable.fontName = "Zapfino "
self.addChild(ScoreLable)
self.addChild(person)
}
func didBeginContact(contact: SKPhysicsContact) {
let firstBody = contact.bodyA
let secondBody = contact.bodyB
if firstBody.categoryBitMask == physicsCatagory.person && secondBody.categoryBitMask == physicsCatagory.IceThree || firstBody.categoryBitMask == physicsCatagory.IceThree && secondBody.categoryBitMask == physicsCatagory.person{
scorenumber++
if scorenumber == 20 {
timePerSpawn = 1.0
}
if scorenumber == 40{
timePerSpawn = 0.89
}
if scorenumber == 60{
timePerSpawn = 0.6
}
if scorenumber == 80{
timePerSpawn = 0.5
}
if scorenumber == 100{
timePerSpawn = 0.4
}
if scorenumber == 120{
timePerSpawn = 0.3
}
ScoreLable.text = "\(scorenumber)"
CollisionWithPerson(firstBody.node as! SKSpriteNode, Person: secondBody.node as! SKSpriteNode)
}
if firstBody.categoryBitMask == physicsCatagory.Score && secondBody.categoryBitMask == physicsCatagory.IceThree ||
firstBody.categoryBitMask == physicsCatagory.IceThree && secondBody.categoryBitMask == physicsCatagory.Score{
lifenumber++
if lifenumber == 1{
//person.texture
person.texture = SKTexture (imageNamed: "Flower#2")
}
if lifenumber == 2{
person.texture = SKTexture (imageNamed: "Flower #3")
}
if lifenumber == 3{
self.view?.presentScene(EndScene())
}
}
}
func CollisionWithPerson (Ice: SKSpriteNode, Person: SKSpriteNode){
Person.removeFromParent()
}
func spawnThirdIce(){
var Ice = SKSpriteNode(imageNamed: "Ice")
Ice.zPosition = 2
Ice.setScale(0.9)
Ice.physicsBody = SKPhysicsBody(rectangleOfSize: Ice.size)
Ice.physicsBody?.categoryBitMask = physicsCatagory.IceThree
Ice.physicsBody?.contactTestBitMask = physicsCatagory.person | physicsCatagory.Score
Ice.physicsBody?.affectedByGravity = false
Ice.physicsBody?.dynamic = true
let MinValue = self.size.width / 8
let MaxValue = self.size.width - 20
let SpawnPoint = UInt32(MaxValue - MinValue)
Ice.position = CGPoint(x: CGFloat(arc4random_uniform(SpawnPoint)), y: self.size.height)
self.addChild(Ice)
let action = SKAction.moveToY(-85, duration: 2.0)
let actionDone = SKAction.removeFromParent()
Ice.runAction(SKAction.sequence([action,actionDone]))
}
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
}
override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
for touch: AnyObject in touches {
let location = touch.locationInNode(self)
let previousTouch = touch.previousLocationInNode(self)
let ammountDragged = location.x - previousTouch.x
person.position.x += ammountDragged
}
}
override func update(currentTime: CFTimeInterval) {
/* Called before each frame is rendered */
if (currentTime - timeOfLastSpawn > timePerSpawn) {
spawnThirdIce()
self.timeOfLastSpawn = currentTime
}
}
}

Answer 1

You might do something like:
if node.position.x > scene.width {
node.position.x = scene.width
}
if node.position.x < 0 {
node.position.x = 0
}