swift - 围绕非 .anchorPoint 的内部点旋转 SkSpriteNode

Question

所以我使用此代码顺时针或逆时针旋转对象。

    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {

    let touch = touches.first 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 == .none) {
        setupRotationWith(direction: newRotationDirection)
        currentRotationDirection = newRotationDirection
    }
}



func reverseRotation(){
    let oldRotateAction = ship.actionForKey("rotate")
    let newRotateAction = SKAction.reversedAction(oldRotateAction!)
    ship.runAction(newRotateAction(), withKey: "rotate")
}



func stopRotation(){
    ship.removeActionForKey("rotate")
}



func setupRotationWith(direction direction: rotationDirection){
    let angle : CGFloat = (direction == .clockwise) ? CGFloat(M_PI) : -CGFloat(M_PI)
    let rotate = SKAction.rotateByAngle(angle, duration: 2)
    let repeatAction = SKAction.repeatActionForever(rotate)
    ship.runAction(repeatAction, withKey: "rotate")
}

我的问题是，这会围绕 SKSpriteNode 的 anchor 创建顺时针或逆时针旋转。

但是，我希望该对象绕 SKSprite 内部的另一个点旋转(类似于 Sprite 图像底部向上 4/5 的位置)。我假设我不能使用通过 CGPointMake 定义的设定点，因为我希望 Sprite 在屏幕上独立移动，但这行不通？

有人有什么建议吗？

Answer 1

您是否尝试过将 Sprite 的 anchorPoint 属性设置为您希望 Sprite 围绕其旋转的点？

ship.anchorPoint = CGPoint(x: 0, y: 4/5)

这是您要找的吗？