如何使用 arc4random 从数组中选择随机 SKShapeNode?
How to choose a random SKShapeNode from an array using arc4random?
我正在尝试使用 sprite kit 和 swift 制作我的第一个应用程序。我创建了一个数组并用两个形状节点填充它(如下所示。
//name the properties for enemy 1
enemy1 = SKShapeNode (rectOfSize: CGSize(width: rectWidth/10, height: rectHeight/10))
enemy1.position = first
enemy1.fillColor = UIColor.blackColor()
enemy1.physicsBody = SKPhysicsBody(rectangleOfSize: CGSize(width: rectWidth, height: rectHeight))
enemy1.physicsBody?.dynamic = true
enemy1.physicsBody?.affectedByGravity = false
//name the properties for enemy 2
enemy2 = SKShapeNode (rectOfSize: CGSize(width: rectWidth/10, height: rectHeight/10))
enemy2.position = second
enemy2.fillColor = UIColor.blackColor()
enemy2.physicsBody = SKPhysicsBody(rectangleOfSize: CGSize(width: rectWidth, height: rectHeight))
enemy2.physicsBody?.dynamic = true
enemy2.physicsBody?.affectedByGravity = false
//populate the arrays
arrayOfEnemies1.addObject(enemy1)
arrayOfEnemies1.addObject(enemy2)
假设我想每 2 秒将这些节点之一随机添加到场景中。我知道使用 arc4random,但我不确定该怎么做。任何帮助将不胜感激。谢谢!
您可以创建一个扩展并获得这样的随机数组元素:
extension Array {
func randomElement() -> T {
let index = Int(arc4random_uniform(UInt32(self.count)))
return self[index]
}
}
像那样:
var randomElement = arrayOfEnemies1.randomElement()
我正在尝试使用 sprite kit 和 swift 制作我的第一个应用程序。我创建了一个数组并用两个形状节点填充它(如下所示。
//name the properties for enemy 1
enemy1 = SKShapeNode (rectOfSize: CGSize(width: rectWidth/10, height: rectHeight/10))
enemy1.position = first
enemy1.fillColor = UIColor.blackColor()
enemy1.physicsBody = SKPhysicsBody(rectangleOfSize: CGSize(width: rectWidth, height: rectHeight))
enemy1.physicsBody?.dynamic = true
enemy1.physicsBody?.affectedByGravity = false
//name the properties for enemy 2
enemy2 = SKShapeNode (rectOfSize: CGSize(width: rectWidth/10, height: rectHeight/10))
enemy2.position = second
enemy2.fillColor = UIColor.blackColor()
enemy2.physicsBody = SKPhysicsBody(rectangleOfSize: CGSize(width: rectWidth, height: rectHeight))
enemy2.physicsBody?.dynamic = true
enemy2.physicsBody?.affectedByGravity = false
//populate the arrays
arrayOfEnemies1.addObject(enemy1)
arrayOfEnemies1.addObject(enemy2)
假设我想每 2 秒将这些节点之一随机添加到场景中。我知道使用 arc4random,但我不确定该怎么做。任何帮助将不胜感激。谢谢!
您可以创建一个扩展并获得这样的随机数组元素:
extension Array {
func randomElement() -> T {
let index = Int(arc4random_uniform(UInt32(self.count)))
return self[index]
}
}
像那样:
var randomElement = arrayOfEnemies1.randomElement()