CODEWITHSUNDEEP
iosxcodeswiftswift2
CodeCake
CodeCake

Reputation: 59

applyImpulse on SKSpriteNode in touchesBegan not working

I'm kinda new to Swift. I have this problem, where the SpriteNode "Ball" is not reacting to applyImpulse command in touchesBegan-method. The overall physicsBody works totally fine, gravity, restitution etc. But nothing is happening, when I use applyImpulse. Here's the code:

var ball = SKSpriteNode()

 override func didMoveToView(view: SKView) {
    /* Setup your scene here */

    self.physicsWorld.gravity = CGVectorMake(0.0, -9.81)


    // Add the ball

    ball = SKSpriteNode(imageNamed: "Ball")
    ball.setScale(2.0)
    ball.position = CGPointMake(self.frame.size.width / 2, self.frame.size.height / 2)
    ball.zPosition = 100.0

    // Physics of the ball
    ball.physicsBody = SKPhysicsBody(circleOfRadius: ball.frame.size.height / 2)
    ball.physicsBody?.allowsRotation = true
    ball.physicsBody?.dynamic = true
    ball.physicsBody?.usesPreciseCollisionDetection = true
    ball.physicsBody?.mass = 2.0
    ball.physicsBody?.restitution = 0.8
    ball.physicsBody?.velocity = CGVectorMake(0.0, 5.0)

    self.addChild(ball)

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
   /* Called when a touch begins */

    self.ball.physicsBody?.applyImpulse(CGVectorMake(0.0, 5.0))



}

Please help me :)

Obviously I have a ground too, this is just the relevant code.

Upvotes: 2

Views: 169

Answers (1)

Alexey Pichukov
Alexey Pichukov

Reputation: 3405

You create local object ball with this line of code:

let ball = SKSpriteNode(imageNamed: "Ball")

inside didMoveToView method. It created and placed to scene with self.addChild(ball). But in this line of code: 

self.ball.physicsBody?.applyImpulse(CGVectorMake(0.0, 5.0))

you call physicsBody?.applyImpulse(CGVectorMake(0.0, 5.0)) from other ball object which is not represented in the code that you posted here. And this object is not the same object you created in didMoveToView method.

You need to init your global for this function ball object in your didMoveToVeiw:

ball = SKSpriteNode(imageNamed: "Ball")

without let keyword

Upvotes: 1

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