如何使用swift在sprite kit中旋转sprite

Question

嗨我的问题是关于两个精灵的旋转.当我触摸屏幕的右半部分时,旋转开始并移动sprite2和sprite3.如果我触摸屏幕的左半部分,旋转会停止,因为速度 - 速度= 0.如果我再次触摸左半部分,旋转开始.

但是,如果我触摸与当前旋转方向相对应的屏幕的一半,则速度会重复.我希望能够改变旋转方向,但速度保持不变.

视频演示了这个问题:http://youtu.be/HxLwl1QZiNM

import SpriteKit

class GameScene: SKScene {
    let sprite = SKSpriteNode(imageNamed:"bWhite")
    let sprite2 = SKSpriteNode(imageNamed:"bBlue")
    let sprite3 = SKSpriteNode(imageNamed:"bRed")
    let circle = SKSpriteNode(imageNamed:"bCircle")       

    override func didMoveToView(view: SKView) {
        /* Setup your scene here */
        backColor = SKColor(red: 0, green: 0, blue: 0, alpha: 1)
        self.backgroundColor = backColor

        sprite.setScale(1.25)
        sprite2.setScale(1)
        sprite3.setScale(1)
        sprite.position = CGPointMake(self.frame.size.width/2, (self.frame.size.height/2)-200);
        circle.position = CGPointMake(self.frame.size.width/2, (self.frame.size.height/2)-200);
        sprite3.zRotation = 172.77
        sprite2.anchorPoint = CGPointMake(-1.10, 0.5);
        sprite3.anchorPoint = CGPointMake(-1.10, 0.5);

        self.addChild(sprite)
        self.addChild(circle)
        sprite.addChild(sprite2)
        sprite.addChild(sprite3)
    }

override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
        /* Called when a touch begins */
        for touch: AnyObject in touches {
            let location = touch.locationInNode(self)

            let action = SKAction.rotateByAngle(CGFloat(M_PI), duration:1)
            let action2 = SKAction.rotateByAngle(CGFloat(-M_PI), duration:1)

            if (location.x > self.frame.size.width / 2)
            {
                sprite2.runAction(SKAction.repeatActionForever(action2))
                sprite3.runAction(SKAction.repeatActionForever(action2))
            } else {
                sprite2.runAction(SKAction.repeatActionForever(action))
                sprite3.runAction(SKAction.repeatActionForever(action))
            }     
        }
    }

Answer 1

好的,拿三个.我不是100%确定旋转何时应该结束的具体细节等等,但所有的部分都应该使用下面的代码.它会:

• 基于第一次触摸的位置顺时针或逆时针开始旋转
• 如果用户再次触摸同一方向,则停止旋转

• 如果用户触摸屏幕的另一半,则切换旋转

    import SpriteKit  
  
    enum rotationDirection{
         case clockwise
         case counterClockwise
         case none
     } 
  
    class GameScene: SKScene {
      var currentRotationDirection = rotationDirection.none
      let sprite = SKSpriteNode(color: UIColor.yellowColor(), size: CGSizeMake(100, 100))
  
      override func didMoveToView(view: SKView) {
        sprite.physicsBody = SKPhysicsBody(rectangleOfSize: sprite.size)
        sprite.physicsBody.affectedByGravity = false
        sprite.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
        self.addChild(sprite)
      }
  
      override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
        let touch : UITouch = touches.anyObject() as UITouch
        let touchPosition = touch.locationInNode(self)
        let newRotationDirection : rotationDirection = touchPosition.x < CGRectGetMidX(self.frame) ? .clockwise : .counterClockwise
  
        if currentRotationDirection != newRotationDirection && currentRotationDirection != .none{
          reverseRotation()
          currentRotationDirection = newRotationDirection
        } else if currentRotationDirection == newRotationDirection{
          stopRotation()
          currentRotationDirection = .none
        } else if (currentRotationDirection == .none){
        setupRotationWith(direction: newRotationDirection)
        currentRotationDirection = newRotationDirection
        }
      }
  
      func reverseRotation(){
        let oldRotateAction = sprite.actionForKey("rotate")
        let newRotateAction = SKAction.reversedAction(oldRotateAction)
        sprite.runAction(newRotateAction(), withKey: "rotate")
      }
  
      func stopRotation(){
        sprite.removeActionForKey("rotate")
      }
  
      func setupRotationWith(#direction: rotationDirection){
        let angle : Float = (direction == .clockwise) ? Float(M_PI) : -Float(M_PI)
        let rotate = SKAction.rotateByAngle(angle, duration: 1)
        let repeatAction = SKAction.repeatActionForever(rotate)
        sprite.runAction(repeatAction, withKey: "rotate")
      }
    }
  

编辑:更改示例以满足问题中的特定需求.代码格式化的东西很奇怪,不太确定那里发生了什么.