ios - SKSpriteNode 减慢但不应该

Question

我试图让我的“词”在屏幕上 float ；恒定速度，无冲击，无重力，无摩擦。一切正常，除了这个词变慢了。

造词代码:

func createWordNode (word: String, atPos: CGPoint) -> SKSpriteNode {

    let doneSize = CGSize(width: 50, height: 50)

    let wordSprite = SKSpriteNode()
    wordSprite.size = CGSize(width: doneSize.width * CGFloat(word.len()), height: doneSize.height)
    wordSprite.position = atPos
    wordSprite.blendMode = .replace
    wordSprite.zPosition = zlvlBG + 1

    let ltrs = Array(word.uppercased().characters)

    for i in 0 ... ltrs.count - 1 {

        let done = SKSpriteNode(imageNamed: "LetterTiles/Tile" + String(ltrs[i]) + ".png")
        done.size = doneSize
        done.position = CGPoint(x: doneSize.width * CGFloat(Double(i) - 1.5), y: 0)
        done.blendMode = .replace
        done.zPosition = zlvlBG + 1

        wordSprite.addChild(done)

    }

    wordSprite.physicsBody?.restitution = 1
    wordSprite.physicsBody?.friction = 0
    wordSprite.physicsBody?.linearDamping = 0
    wordSprite.physicsBody?.angularDamping = 0
    wordSprite.physicsBody?.mass = 2000

    wordSprite.physicsBody = SKPhysicsBody(rectangleOf: wordSprite.size)
    wordSprite.physicsBody?.collisionBitMask = 0
    wordSprite.physicsBody?.contactTestBitMask = 0
    wordSprite.physicsBody?.categoryBitMask = categoryWords
    wordSprite.physicsBody?.fieldBitMask = 0

    wordSprite.physicsBody?.isDynamic = true
    wordSprite.physicsBody?.affectedByGravity = false
    wordSprite.physicsBody?.allowsRotation = false

    var velocity = CGVector()
    velocity.dx = 100
    velocity.dy = 0
    wordSprite.physicsBody?.velocity = velocity
    wordSprite.physicsBody?.applyImpulse(velocity)

    wordSprite.name = "Word:" + word


    return wordSprite
}

我这样调用函数:

addChild (createWordNode(word: "Done", atPos: CGPoint(x:-500, y:450)))

知道为什么 word 变慢了吗？ 谢谢。

Answer 1

看起来您正在创建一个不需要在物理模拟中的对象。因此，您可能需要重新考虑简单地删除与物理相关的代码并手动更新节点 position。

也就是说，如果您希望此节点保留在物理模拟中。在开始尝试修改属性之前，您需要将 SKPhysicsBody 添加到 SKSpriteNode。例如

wordSprite.physicsBody = SKPhysicsBody(rectangleOf: wordSprite.size)
wordSprite.physicsBody?.restitution = 1
wordSprite.physicsBody?.friction = 0
wordSprite.physicsBody?.linearDamping = 0
wordSprite.physicsBody?.angularDamping = 0
wordSprite.physicsBody?.mass = 2000