触摸开始时尝试旋转鸟，触摸结束时向下旋转（SceneKit）

Question

当我触摸屏幕时，鸟儿以正确的角度向上旋转，但一旦触摸结束就停留在那里。

我游戏中的墙壁已停止产卵了！？

这是我的代码，如果有人能看到我做错了什么让我知道：D。 非常感激。谢谢

  override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {


    if gameStarted == false{

        gameStarted = true

        bird.physicsBody?.affectedByGravity = true



        let spawn = SKAction.run({
            () in

            self.createWalls()

        })
        let delay = SKAction.wait(forDuration: 2.0)
        let spawnDelay = SKAction.sequence([delay, spawn])
        let spawnDelayForever = SKAction.repeatForever(spawnDelay)
        self.run(spawnDelayForever)


        let distance = CGFloat(self.frame.width + wallPair.frame.width)
        let movePipes = SKAction.moveBy(x: -distance - 50, y: 0, duration: TimeInterval( 0.01 * distance))
        let removePipes = SKAction.removeFromParent()
        moveAndRemove = SKAction.sequence([movePipes,removePipes])

        bird.physicsBody?.velocity = CGVector(dx: 0, dy: 0)
        bird.physicsBody?.applyImpulse(CGVector(dx: 0, dy: 35))

        let rotateUp = SKAction.rotate(byAngle: 0.2, duration: 0)
        bird.run(rotateUp)


    }
    else{

        if died == true{

        }
        else{
            bird.physicsBody?.velocity = CGVector(dx: 0, dy: 0)
            bird.physicsBody?.applyImpulse(CGVector(dx: 0, dy: 35))



        }
    }

    for touch in touches{

        let location = touch.location(in: self)

        if died == true{

            if restartButton.contains(location){
                restartScene()
            }
        }
    }



override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {


    if gameStarted == false{
        gameStarted = true

        bird.physicsBody?.affectedByGravity = true

        let rotateDown = SKAction.rotate(byAngle: -0.2, duration: 0)
        bird.run(rotateDown)

    }
}