xcode - 快速生成节点无限

Question

我试图让我的节点在屏幕上移动并在计时器上无限生成。我也想同时在屏幕上显示多个节点。这是迄今为止我的稳定代码。我尝试了多种不同的方法，要么卡住，要么崩溃。

 let bunnyTexture = SKTexture(imageNamed: "oval 1.png")
    bunny = SKSpriteNode(texture: bunnyTexture)
    bunny.position = CGPoint(x: (size.width / 3), y: 750 + bunny.frame.height)
    self.addChild(bunny)
    bunny.physicsBody = SKPhysicsBody(circleOfRadius: bunnyTexture.size().height/2)
    bunny.physicsBody!.dynamic = true
    let spawnBunny = SKAction.moveByX(0, y: -self.frame.size.height, duration: 4)
    let despawnBunny = SKAction.removeFromParent()
    let spawnNdespawn2 = SKAction.sequence([spawnBunny, despawnBunny])
    bunny.runAction(spawnNdespawn2)

    let gobblinTexture = SKTexture(imageNamed: "oval 2.png")
    gobblin = SKSpriteNode(texture: gobblinTexture)
    gobblin.position = CGPoint(x: 150 + gobblin.frame.width, y: (size.height / 3))
    self.addChild(gobblin)
    let randomGob = arc4random() % UInt32(self.frame.size.height / 2)
    let spawnGob = SKAction.moveByX(+self.frame.size.width, y: 0, duration: 4)
    let despawnGob = SKAction.removeFromParent()
    let spawnNdespawn = SKAction.sequence([spawnGob, despawnGob])
    gobblin.runAction(spawnNdespawn)

    let ground = SKNode()
    ground.position = CGPointMake(0, 0)
    ground.physicsBody = SKPhysicsBody(rectangleOfSize: CGSizeMake(self.frame.size.width, -50))
    ground.physicsBody!.dynamic = false
    self.addChild(ground)

Answer 1

您可以使用SKAction.waitForDuration(interval)创建循环计时器。

使用新函数loopAction扩展SKNode。这需要一个 SKAction 、一个 NSTimeInterval 和一个 () -> Bool 函数。

SKAction 是在每个时间间隔执行的函数。() -> Bool 函数将用于停止否则的无限循环。

请记住，这会捕获 SKNode 和 SKAction。在循环停止之前，两者都不会释放。

可以创建一个带有标志 (Bool) 的对象来保存所有这些信息，并在需要停止时将标志设置为 false。我只是更喜欢这种方式。

LoopActionManager 是如何实现loopAction 的示例。您需要一个 SKNode 和一个 SKAction。您不是在 SKNode 上调用 runAction，而是调用 loopAction 并传递间隔和控制何时停止的函数。 您可以将此代码放置在您有权访问相关节点的位置。

停止函数也可以作为尾随闭包实现

将代码粘贴到 Playground 中以查看其工作原理。

import UIKit
import SpriteKit
import XCPlayground



extension SKNode {

    func loopAction(action:SKAction,interval:NSTimeInterval,continueLoop:() -> Bool) {

        guard continueLoop() else { return }

        runAction(SKAction.waitForDuration(interval)) {

            if continueLoop() {
                self.runAction(action)
                self.loopAction(action, interval: interval, continueLoop: continueLoop)
            }
        }
    }
}

// example
class LoopActionManager {

    let node = SKSpriteNode(color: UIColor.whiteColor(), size: CGSize(width: 20, height: 20))
    let action = SKAction.moveBy(CGVector(dx: 10,dy: 0), duration: 0.5)

    func continueMoveLoop() -> Bool {
        return (node.position.x + node.size.width) < node.scene?.size.width
    }

    func start() {
        node.loopAction(action, interval: 1, continueLoop: continueMoveLoop)
    }

}

let view = SKView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
let scene = SKScene(size: view.frame.size)
view.presentScene(scene)

let example = LoopActionManager()
scene.addChild(example.node)
example.start()



XCPlaygroundPage.currentPage.liveView = view

<小时/>

正如下面的评论中所述，也可以使用repeatAction。您可以使用static func 扩展SKAction，以根据要重复的操作和间隔生成repeatAction。与第一个解决方案相比，这个解决方案更简单并且更符合SDK。您确实会丢失每个间隔的完成处理程序。

import UIKit
import SpriteKit
import XCPlayground


extension SKAction {

    static func repeatAction(action:SKAction,interval:NSTimeInterval) -> SKAction {

        // diff between interval and action.duration will be the wait time. This makes interval the interval between action starts. Max of 0 and diff to make sure it isn't smaller than 0
        let waitAction = SKAction.waitForDuration(max(0,interval - action.duration))
        let sequenceAction = SKAction.sequence([waitAction,action])
        let repeatAction = SKAction.repeatActionForever(sequenceAction)

        return repeatAction

    }
}


let view = SKView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
let scene = SKScene(size: view.frame.size)
view.presentScene(scene)

let node = SKSpriteNode(color: UIColor.whiteColor(), size: CGSize(width: 20, height: 20))
let action = SKAction.moveBy(CGVector(dx: 10,dy: 0), duration: 0.5)

scene.addChild(node)
node.runAction(SKAction.repeatAction(action, interval: 1.0))



XCPlaygroundPage.currentPage.liveView = view