您可以更轻松地创建一种基于给定矩形生成随机点的方法。或在给定矩形内生成精灵的方法,如下所示:
import SpriteKit
class GameScene: SKScene {
let rect = CGRect(x: 90, y: 360, width: 200, height: 200)
override func didMoveToView(view: SKView) {
let debug = SKSpriteNode(color: SKColor.redColor(), size: rect.size)
debug.alpha = 0.2
debug.position = rect.origin
let origin = SKSpriteNode(color: SKColor.redColor(), size:CGSize(width: 5, height:5))
debug.addChild(origin)
self.addChild(debug)
}
override func touchesBegan(touches: NSSet, withEvent event: UIEvent) {
let sprite = spawnSpriteAtRandomPositionWithinRect(rect)
self.addChild(sprite)
println("Sprite spawned at position x,y( \(sprite.position.x), \(sprite.position.y))")
}
func randomBetweenNumbers(firstNum: CGFloat, secondNum: CGFloat) -> CGFloat{
return CGFloat(arc4random()) / CGFloat(UINT32_MAX) * abs(firstNum - secondNum) + min(firstNum, secondNum)
}
func spawnSpriteAtRandomPositionWithinRect(rectangle:CGRect)->SKSpriteNode{
let x = randomBetweenNumbers(rectangle.origin.x - rectangle.size.width / 2.0 , secondNum: rectangle.origin.x + rectangle.size.width/2.0)
let y = randomBetweenNumbers(rectangle.origin.y - rectangle.size.height / 2.0 , secondNum: rectangle.origin.y + rectangle.size.height/2.0)
let sprite = SKSpriteNode(color: SKColor.greenColor(), size:CGSize(width: 30, height: 30))
sprite.position = CGPoint(x: x, y: y)
return sprite
}
}
实际上不需要名为debug的Sprite ,但它可以直观地显示给定的矩形。