getting incorrect rotation when trying to increment a sprite's zRotation by 1 degree with button press

Question

I have a simple rectangular sprite and want to rotate this sprite by 1 degree every time I press a button on screen. I have some simple code I expected to work but it's giving odd results. Instead of rotating the rectangle by 1 degree it seems to be rotating it by at least 180-270 degrees per tap.

var degrees = 0

 override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    let touch = touches.first
    let touchLocation = touch!.location(in: self)
    let beam = childNode(withName: "beam") as! SKSpriteNode


    if let body = physicsWorld.body(at: touchLocation) {
        if body.node!.name == "leftTap" {
            print("Began touch on Left")
            beam.zRotation = CGFloat(degrees)
            degrees = degrees + 1

        }else{
            print("Began touch on right")
        }
    }
}

In the GameScene.sks sprite attribute inspector you can increment the rotation by pressing the "+" or "-" button. I figured this would work the same way, but I must not be understanding something about the rotation principals here.

any advice would be appreciated.

Answer 1

It's not degrees, it's rads. a value of 3 or so (pi) is a full spin.

https://developer.apple.com/documentation/spritekit/sknode/1483089-zrotation

Here is a handy extension you can use:

extension SKNode {
  // Usage is node.rotateBy(45) etc:
  func rotateBy(_ degree: CGFloat) {
    let conversionFactor = CGFloat(0.01745329252)
    self.run(.rotate(byAngle: degree * conversionFactor, duration: 0))
  }
}