我的初始管道与以下管道不同

Question

我正在制作一个游戏，假设球经过一些管道，当玩家接触到管道时，游戏停止。有点像飞扬的鸟。我唯一的问题是初始管道阻塞了整个屏幕，而其余的管道则按照我的要求放置和随机化。这怎么可能？

这是球类：

window.setTimeout()

这是随机类：

import SpriteKit

struct ColliderType {
static let Ball: UInt32 = 1
static let Pipes: UInt32 = 2
static let Score: UInt32 = 3
}

class Ball: SKSpriteNode {

func initialize() {
    self.name = "Ball"
    self.zPosition = 1
    self.anchorPoint = CGPoint(x: 0.5, y: 0.5)
    self.physicsBody = SKPhysicsBody(circleOfRadius: self.size.height / 
2)
    self.setScale(0.7)
    self.physicsBody?.affectedByGravity = false
    self.physicsBody?.categoryBitMask = ColliderType.Ball
    self.physicsBody?.collisionBitMask = ColliderType.Pipes
    self.physicsBody?.contactTestBitMask = ColliderType.Pipes | 
ColliderType.Score
}
}

这是GameplayScene：

import Foundation
import CoreGraphics

public extension CGFloat {

public static func randomBetweenNumbers(firstNum: CGFloat, secondNum: 
CGFloat) -> CGFloat {

    return CGFloat(arc4random()) / CGFloat(UINT32_MAX) * abs(firstNum - 
secondNum) + firstNum

}


}