使用SKCropNode（）的SKNode（）的淡出操作（）兒童

Question

我有一個SKNode（），它有SKCropNode（）子元素。我能夠運行所有類型的動作來旋轉和縮放我的SKNode（），但是當我想要使用任何類型的淡入淡出操作時，結果總是爲alpha 1或alpha 0。沒有任何淡入淡出的方式。

通過用SKShapeNode（）替換SKCropNode（）淡出操作正常工作。

誰能告訴我爲什麼？是不是可以淡化蒙面節點？

import SpriteKit 

class GameScene: SKScene { 

let player = SKNode() 
let playerSize = CGFloat(50) 
let playerCrop = SKCropNode() 
let playerMask = SKSpriteNode(color: SKColor.blackColor(), size: CGSizeMake(CGFloat(100), CGFloat(100))) 
let playerCircle = SKShapeNode(circleOfRadius: CGFloat(100)) 

let playerCenterMask = SKShapeNode(circleOfRadius: CGFloat(100)) 
let playerCenterCrop = SKCropNode() 

override func didMoveToView(view: SKView) { 

    backgroundColor = SKColor.blackColor() 

    player.position = CGPoint(x:CGRectGetMidX(self.frame), y:CGRectGetMidY(self.frame)) 
    player.alpha = 0 
    addChild(player) 

    playerCenterMask.lineWidth = 20   
    playerCenterCrop.maskNode = playerCenterMask 

    playerMask.position.x = -playerSize 
    playerMask.position.y = playerSize 
    playerCircle.lineWidth = 0 
    playerCircle.fillColor = SKColor.redColor() 
    playerCrop.addChild(playerCircle) 
    playerCrop.maskNode = playerMask 

    playerCenterCrop.addChild(playerCrop) 
    player.addChild(playerCenterCrop) 

    // Animations 
    let playerScale = SKAction.scaleTo(2.0, duration: 5) 
    let playerFadeIn = SKAction.fadeInWithDuration(5) 
    let playerAnimation = SKAction.group([playerScale,playerFadeIn]) 

    player.runAction(playerAnimation, completion: {}) 

} 

} 

Answer 1

作爲評價提到： SKCropNode使用阿爾法< 0.5至不畫。 > = 0.5來繪製，並且你不能設置混合模式，所以它可能在做源混合模式。這意味着它覆蓋了alpha。後來的孩子們混合在一起。

玩家上下文被創建，它在給定的alpha處繪製，然後繪製SKCropNode，覆蓋alpha而不是混合。

對您的孩子運行淡入淡出，而不是您的父母，以獲得您正在查找的結果。

這裏是你的源看起來像一個變化：

import SpriteKit 

class GameScene: SKScene { 

    let player = SKNode() 
    let playerSize = CGFloat(50) 
    let playerCrop = SKCropNode() 
    let playerMask = SKSpriteNode(color: SKColor.blackColor(), size: CGSizeMake(CGFloat(100), CGFloat(100))) 
    let playerCircle = SKShapeNode(circleOfRadius: CGFloat(100)) 

    let playerCenterMask = SKShapeNode(circleOfRadius: CGFloat(100)) 
    let playerCenterCrop = SKCropNode() 

    override func didMoveToView(view: SKView) { 

     backgroundColor = SKColor.blackColor() 

     player.position = CGPoint(x:CGRectGetMidX(self.frame), y:CGRectGetMidY(self.frame)) 
     player.alpha = 1 
     addChild(player) 
     playerCircle.alpha = 0 
     playerCenterMask.lineWidth = 20 
     playerCenterCrop.maskNode = playerCenterMask 

     playerMask.position.x = -playerSize 
     playerMask.position.y = playerSize 
     playerCircle.lineWidth = 0 
     playerCircle.fillColor = SKColor.redColor() 
     playerCrop.addChild(playerCircle) 
     playerCrop.maskNode = playerMask 
     playerCenterCrop.addChild(playerCrop) 
     player.addChild(playerCenterCrop) 

     // Animations 
     let playerScale = SKAction.scaleTo(2.0, duration: 5) 
     let playerFadeIn = SKAction.fadeInWithDuration(5) 
     let playerAnimation = playerScale 

     player.runAction(playerAnimation, completion: {}) 
     playerCircle.runAction(playerFadeIn, completion: {}) 

    } 

}