CODEWITHSUNDEEP
iosswiftsprite-kitskphysicsbody
Dyldo42
Dyldo42

Reputation: 2348

Angular damping being applied to SpriteKit nodes despite setting value to zero

I have implemented a simple pendulum in SpriteKit that I want to continue swinging forever. I've set the angularDamping of all of my physics bodies to 0, but the pendulum still slows down (eventually coming to a complete stop). Here's my code:

// In viewDidLoad

scene = SKScene(size: view.bounds.size)
scene.backgroundColor = .white

let anchor = SKShapeNode(circleOfRadius: 10)
anchor.physicsBody = .init(circleOfRadius: 10)
anchor.position = .init(x: scene.size.width / 2, y: scene.size.height / 2)
anchor.physicsBody!.isDynamic = false
anchor.physicsBody!.angularDamping = 0
scene.addChild(anchor)

let length: CGFloat = 100

let ball = SKShapeNode(circleOfRadius: 5)
ball.physicsBody = .init(circleOfRadius: 5)
ball.physicsBody!.angularDamping = 0
ball.position = .init(x: length, y: 0)
anchor.addChild(ball)

let jointPath = CGMutablePath()
jointPath.move(to: .zero)
jointPath.addLine(to: .init(x: length, y: 0))

let joint = SKShapeNode(path: jointPath)
joint.strokeColor = .black
joint.lineWidth = 5
joint.position = anchor.convert(.zero, to: ball)
ball.addChild(joint)

let pin = SKPhysicsJointPin.joint(
    withBodyA: anchor.physicsBody!,
    bodyB: ball.physicsBody!,
    anchor: scene.convert(.zero, from: anchor)
)
pin.frictionTorque = 0
scene.physicsWorld.add(pin)

let skView = SKView(frame: view.bounds)
skView.presentScene(scene)
view.addSubview(skView)

I've tried setting other friction-related values, e.g: frictionTorque on the SKPhysicsJointPin, but nothing has worked.

Upvotes: 0

Views: 45

Answers (0)

Related Questions