ios - SKAction.rotate 未在 SKCameraNode 上运行

Question

所以实际的 SKCameraNode 工作正常，因为我让它跟随另一个节点并且工作正常。但是当我尝试使用 SKAction 旋转相机时，它不会旋转。但是，当我尝试设置它的 zRotation 时，它工作正常。我真的不明白为什么。

这里是一些摘录。

import SpriteKit

class Field:SKScene {
  let screen = UIScreen.main.bounds
  var cam = SKCameraNode()
  var ball:SKShapeNode = SKShapeNode()

  override func didMove(to view: SKView) {
    // ball init and other stuff
    scene!.camera = cam
  }

  func followBall() {
    cam.position.x = ball.position.x
    cam.position.y = ball.position.y+100
  }

  override func update(_ currentTime: TimeInterval) {
    followBall()
  }

  override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    for touch in touches {
      let location = touch.location(in: self.cam)
      if(location.x < screen.width/2) {
        cam.run(SKAction.rotate(toAngle: .pi/8, duration: 0.2))
      } else if (location.x > screen.width/2) {
        cam.run(SKAction.rotate(toAngle: -.pi/8, duration: 0.2))
      }
    }
  }

  override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    cam.run(SKAction.rotate(toAngle: 0, duration: 0.2))
  }
}

Answer 1

cam 未添加到场景中 @0x141E 提供了答案。