swift - Swift SKShapeNode shapeWithSplinePoints

Question

我正在尝试为要遵循的节点创建 CGPath，但是当我尝试使用 SKShapeNode 中定义的动作和常量从 608_hd_best_practices_for_building_spritekit_games 滑动时，我得到错误Extra argument 'count' in call。有什么想法吗？

import SpriteKit

class GameScene: SKScene {
    var groundNode: SKSpriteNode? = SKSpriteNode()
    var path = [CGPoint]()

    override func didMoveToView(view: SKView) {
        groundNode = childNodeWithName("ground") as? SKSpriteNode
    }

    override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
        path = [CGPoint]()
    }

    override func touchesMoved(touches: NSSet, withEvent event: UIEvent) {
        var newPoint = touches.anyObject()?.locationInNode(groundNode)
        path.append(newPoint!)
    }

    override func touchesEnded(touches: NSSet, withEvent event: UIEvent) {
        let sprite = SKSpriteNode(imageNamed:"Spaceship")

        sprite.xScale = 0.25
        sprite.yScale = 0.25
        sprite.position = path.first!

        groundNode?.addChild(sprite)

        // TODO: this currently isnt working
        let count = path.count
        // CGPathRef p = [SKShapeNode shapeWithSplinePoints:points]
        let p: CGPathRef = SKShapeNode(splinePoints: path, count: count)

        let speed:CGFloat = 1.0

        let action = SKAction.followPath(p, speed: speed)
        sprite.runAction(action)
    }

    override func update(currentTime: CFTimeInterval) {
        /* Called before each frame is rendered */
    }
}

Answer 1

init(splinePoints:count:)将一个UnsafeMutablePointer<CGPoint>（即一个CGPoints 的 C 数组）和一个无符号整数作为其参数。它还返回一个SKShapeNode对象而不是CGPathRef. 尝试以下...

let p = SKShapeNode(splinePoints: &path, count: UInt(count))

编辑：也进行以下更改

let speed:CGFloat = 1.0

let action = SKAction.followPath(p.path, speed: speed)
sprite.runAction(action)