swift - 蛇在垂直方 block 中移动

Question

我正在尝试使用 SpriteKit 制作蛇游戏(就像旧诺基亚手机中的游戏)。问题是，当蛇的方向改变时，蛇在一个静止的垂直 block 中移动，并没有得到 L 形(如图所示)。为了进入上下文，我有一个名为 SKDSpriteNode 的类，它与 SKSpriteNode 相同，但有一个额外的 direction 属性； Snake 类有 direction 和 length 属性。有一个 snakeBody 属性，类型为 [SKDSpriteNode]，包含蛇体的节点。

蛇的方向在游戏开始时分配给.up，然后由用户的滑动分配。顺便说一句，changeDirection 方法在蛇的方向改变时被调用(使用 didSet)。这是代码和图片:

extension ClassicLevelScene {

func startGame() { snake.direction = .up; moveSnake() }

func checkPlacement(for node: SKDSpriteNode) -> SKAction {
    return SKAction.run({
        if !(node.isInsideFrame(of: self)) { self.gameOver() }
    })
}

func getMovement(for node: SKDSpriteNode) -> (once: SKAction, repetitive: SKAction) {
    let movement = SKAction.move(by: node.direction.getVector(withIntensity: movementSpeed), duration: 0.5)
    let moveAction = SKAction.sequence([movement, checkPlacement(for: node)])
    let repetitiveMoveAction = SKAction.repeatForever(moveAction)
    return (moveAction, repetitiveMoveAction)
}

func moveSnake() {
    for node in snakeBody { 
        node.removeAllActions()
        node.run(getMovement(for: node).1) 
    }
}

func moveOnce() {
    for node in snakeBody { 
        node.removeAllActions()
        node.run(getMovement(for: node).0) 
    }
}

func changeDirection() {
    for i in 0..<snake.length {
        if i == 0 {
            snakeBody[i].direction = snake.direction
            snakeBody[i].run(SKAction.move(by: snakeBody[i].direction.getVector(withIntensity: movementSpeed), duration: 0.5))
        } else {
            snakeBody[i].direction = snakeBody[i-1].direction
            snakeBody[i].run(SKAction.move(to: snakeBody[i-1].oldPosition, duration: 0.5))
        }
    }
}

Answer 1

我需要发布一个答案来向您展示代码，但您应该只移动头部，让尾部拖在后面。现在有更好的方法可以做到这一点，但是为了简化您已经编写的代码，它应该是这样的

extension ClassicLevelScene {

    func startGame() { snake.direction = .up; moveSnake() }

    func checkPlacement(for node: SKSpriteNode) -> SKAction {
        return SKAction.run({
            if !(node.isInsideFrame(of: self)) { self.gameOver() }
        })
    }

    func getMovement(for node: SKDSpriteNode) -> (once: SKAction, repetitive: SKAction) {
        let movement = SKAction.move(by: node.direction.getVector(withIntensity: movementSpeed), duration: 0.5)
        let moveTail = SKAction.run({self.moveTail()})
        let moveAction = SKAction.sequence([movement, moveTail,checkPlacement(for: node)])
        let repetitiveMoveAction = SKAction.repeatForever(moveAction)
        return (moveAction, repetitiveMoveAction)
    }

    func moveTail()
    {
        for i in 1..<snake.length {
                snakeBody[i].direction = snakeBody[i-1].direction
                snakeBody[i].position = snakeBody[i-1].oldPosition
        }
    }

    func moveSnake() {
        let head = snakeBody[0] { 
            head.removeAllActions()
            head.run(getMovement(for: head).1) 
        }
    }

    func moveOnce() {
        let head = snakeBody[0] { 
            head.removeAllActions()
            head.run(getMovement(for: head).0) 
        }
    }

    func changeDirection() {
            let head = snakeBody[0] { 
            head.removeAllActions()
            head.direction = snake.direction
            head.run(SKAction.move(by:  head.direction.getVector(withIntensity: movementSpeed), duration: 0.5))
    }
}