ios - 将一个 Sprite 保留在屏幕内，但让其他 Sprite 离开

Question

我正在制作一款游戏，用户可以移动宇宙飞船并发射子弹。我想让用户无法将宇宙飞船移出屏幕，但是当子弹发射时，他们可以离开屏幕。我怎样才能做到这一点？我在下面附上了一张截图。

 override func didMoveToView(view: SKView) {



    let borderBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
    self.physicsBody = borderBody
    borderBody.friction = 0
    borderBody.restitution = 0

    Bullet.hidden = true


    buttonDirUp.position = CGPoint(x: -200, y: -50)
    buttonDirUp.setScale(2.0)
    self.addChild(buttonDirUp)

    ship.setScale(0.33)
    shootButton.setScale(0.7)

    buttonDirLeft.position = CGPoint(x: -250, y: -100)
    buttonDirLeft.setScale(2.0)
    self.addChild(buttonDirLeft)

    buttonDirDown.position = CGPoint(x: -200, y: -150)
    buttonDirDown.setScale(2.0)
    self.addChild(buttonDirDown)

    buttonDirRight.position = CGPoint(x: -150, y: -100)
    buttonDirRight.setScale(2.0)
    self.addChild(buttonDirRight)

    self.view?.multipleTouchEnabled = true

    self.backgroundColor = SKColor.blackColor()

    self.anchorPoint = CGPointMake(0.5, 0.5)

    self.addChild(base)
    base.position = CGPointMake(200, -100)

    self.addChild(ball)
    ball.position = base.position

    self.addChild(ship)
    ship.position = CGPoint(x: self.frame.midX, y: self.frame.midY)

    self.addChild(shootButton)
    shootButton.position = CGPoint(x: self.frame.midX, y: -100)

    ball.zPosition = 1
    base.zPosition = 0

    ball.alpha = 0.4
    shootButton.alpha = 0.4
    base.alpha = 0.4
    buttonDirRight.alpha = 0.4
    buttonDirLeft.alpha = 0.4
    buttonDirUp.alpha = 0.4
    buttonDirDown.alpha = 0.4

}

Screenshot

Answer 1

您只需在 View 周边设置节点，然后使用 spaceship 的碰撞位掩码并将其设置为等于您为周边建立的所有节点。

spaceShip.physicsBody?.collisionBitMask = PhysicsCategory.firstNode | PhysicsCategory.secondNode | PhysicsCategory.thirdNode | PhysicsCategory.fourthNode