我有一个移动精灵的应用程序。一旦我滑动\触摸精灵 - 它就会消失。我还做的是，在精灵消失的位置，我产生了一个Smoke粒子发射器。但它一直在“运行”，而我希望它“淡出”......分散..所以现在它对我有用的方式是我产生的是一个出生率= 100并且一旦新的精灵添加到屏幕上（添加每半秒一次）我将它的出生率改为0.
它确实产生了一种效果......我想要的是什么，但它已经被摧毁而且不理想。
我可以以某种方式将发射器设置在位置，并从那一刻开始使其在给定时间内“消失”吗？例如，在1秒内将它的出生率从100减少到0，但异步！
代码是这样的：
GameScene.swift
class GameScene: SKScene,SKPhysicsContactDelegate {
var spriteSmoke = SKEmitterNode(fileNamed: "GoneSpriteSmoke")
override func didMoveToView(view: SKView) {
spriteSmoke.position = CGPointMake(-100, -100)
self.addChild(spriteSmoke)
spriteSmoke.targetNode = self
}
override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent)
{
let touch = touches.first as! UITouch
let location = touch.locationInNode(self)
//i have a sprite name check implemented to remove correct sprites.
if let theName = self.nodeAtPoint(location).name {
if theName == task.lowercaseString {
//sprite has to be removed
//spawn smoke on it's place
spriteSmoke.particleBirthRate = 200
spriteSmoke.position = location
self.removeChildrenInArray([self.nodeAtPoint(location)])
}
}
}
func addFood() {
//this func is called from another routine, every .5 sec.
//SETTING UP THE SPRITE HERE
//position, scale and so on...
//adding new sprite to the scene
addChild(food)
//setting the existing SMOKE emmiter to the 0 BR to simulate it's fading away.
//Since this func is called each 0.5 sec, it works OK-iiissshhhhh if in those 0.5 sec any smoke emitter was places.
spriteSmoke.particleBirthRate = 0
}