Sprite kit SpriteKit：将船顺时针旋转一圈

在SpriteKit中，我想定位一个宇宙飞船sprite，以便：

（a） 顺时针或逆时针旋转

（b） 精灵旋转，它的鼻子总是指向中心，不管它在圆上的什么位置

目前我有以下输出：

我的理想输出如图所示

我的代码如下：

类游戏场景：SKScene{

lazy var circleNode:SKShapeNode = {
    var circle = SKShapeNode(circleOfRadius: 200)
    circle.position = CGPoint(x: frame.midX, y: frame.midY)
    circle.strokeColor = SKColor.purple
    circle.lineWidth = 10.0
    circle.glowWidth = 2.0
    circle.physicsBody?.isDynamic = false
    return circle
}()

lazy var shipNode: SKSpriteNode = {
    var sprite = SKSpriteNode(imageNamed: "ship")
    sprite.position = CGPoint(x: circleNode.frame.minX, y: circleNode.frame.minY)
    sprite.xScale = 2
    sprite.yScale = 2
    sprite.zPosition = 1
    return sprite
}()

class func newGameScene() -> GameScene {
    // Load 'GameScene.sks' as an SKScene.
    guard let scene = SKScene(fileNamed: "GameScene") as? GameScene else {
        print("Failed to load GameScene.sks")
        abort()
    }

    // Set the scale mode to scale to fit the window
    scene.scaleMode = .aspectFill

    return scene
}    

func setUpScene() {
    self.addChild(circleNode)
    self.addChild(shipNode)
}

override func didMove(to view: SKView) {
    self.setUpScene()
}

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {

    let touch = touches.first
    if let location = touch?.location(in: self){
        if location.x > shipNode.position.x {
            let moveToRight = SKAction.moveBy(x: 1, y: 0, duration: 5)
            let forever = SKAction.repeatForever(moveToRight)
            shipNode.run(forever, withKey: "move")
        }else{
            let moveToLeft = SKAction.moveBy(x: -1, y: 0, duration: 5)
            let forever = SKAction.repeatForever(moveToLeft)
            shipNode.run(forever, withKey: "move")
        }
    }

}

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    shipNode.removeAction(forKey: "move")
}

但这里的问题是，它是围绕着路径自身设置动画的，这不是我想要的。相反，只有用户触摸才能使飞船顺时针或逆时针移动

我如何确保：

（a） 精灵坐在圆形的小路上 （b） 精灵的鼻子总是指向圆心

---

非常感谢

您可以通过将船舶添加到集装箱（一个

SKNode

），将船舶定位在圆上的一个点上（零度），将船舶指向圆的中心，然后旋转集装箱来实现这一点。下面是一个示例

let sprite = SKSpriteNode(imageNamed:"your_ship_name")
let container = SKNode()

override func didMove(to view:SKView) {
    let numRotations:CGFloat = 100
    let circleRadius:CGFloat = 200

    addChild(container)
    // Rotate so the ship initially points to the center
    sprite.zRotation = CGFloat.pi/2
    sprite.position = CGPoint(x: circleRadius, y: 0)
    container.addChild(sprite)

    let rotate = SKAction.rotate(byAngle: 2 * CGFloat.pi * numRotations, duration: 5 * TimeInterval(numRotations))

    container.run(rotate.reversed())
}

---

听起来不错，我稍后会试试。非常感谢这个答案，简单、优雅，绝对不需要过多的计算。您好0x141E您的解决方案效果很好。飞船现在坐在圆圈上，绕着圆圈移动，并指向屏幕的中心！非常感谢！

let sprite = SKSpriteNode(imageNamed:"your_ship_name")
let container = SKNode()

override func didMove(to view:SKView) {
    let numRotations:CGFloat = 100
    let circleRadius:CGFloat = 200

    addChild(container)
    // Rotate so the ship initially points to the center
    sprite.zRotation = CGFloat.pi/2
    sprite.position = CGPoint(x: circleRadius, y: 0)
    container.addChild(sprite)

    let rotate = SKAction.rotate(byAngle: 2 * CGFloat.pi * numRotations, duration: 5 * TimeInterval(numRotations))

    container.run(rotate.reversed())
}