检查节点是否在屏幕外

Question

我的屏幕上有一个节点随陀螺仪移动。但我不能将它的位置限制在屏幕上，我试过了，但它只对底部和顶部有效：

override func update(currentTime: CFTimeInterval){

     ...

     if sprite.position.x <= sprite.frame.width / 2 {
          print("out on the left of the screen")
     }
     if sprite.position.x >= self.frame.width - sprite.frame.width / 2 {
          print("out on the right of the screen")
     }
     if sprite.position.y <= sprite.frame.height / 2 {
          print("out on the top of the screen")
          //worked
     }
     if sprite.position.y <= self.frame.height - sprite.frame.height / 2 {
          print("out on the bottom of the screen")
          //worked
     }

}

Answer 1

override func update(currentTime: CFTimeInterval){

 ...

 if sprite.position.x <= 0 {
      print("out on the left of the screen")
 }
 if sprite.position.x >= self.size.width {
      print("out on the right of the screen")
 }
 if sprite.position.y <= sprite.frame.height / 2 {
      print("out on the top of the screen")
      //worked
 }
 if sprite.position.y <= self.frame.height - sprite.frame.height / 2 {
      print("out on the bottom of the screen")
      //worked
 }

}

要检测精灵是否向左离开屏幕，您将精灵 x 坐标与 x=0 进行比较，并查看精灵是否向右离开屏幕，您可以与场景宽度。

Answer 2

既然你想阻止精灵离开屏幕，我建议你使用 Sprite Kit 的物理引擎。

首先，给你的精灵添加一个SKPhysicsBody，例如：

sprite.physicsBody = SKPhysicsBody(rectangleOfSize: sprite.size)

其次，需要在场景中添加物理体，例如：

override func didMoveToView(view: SKView) {
    super.didMoveToView(view)
    self.physicsBody = SKPhysicsBody(edgeLoopFromRect: view.bounds)
}

最后，既然你想禁用重力，你可以只为 sprite:

禁用它

sprite.physicsBody!.affectedByGravity = false
// force unwrapping here is okay because we're SURE sprite has a physics body.

或者，禁用场景中所有内容的重力：

self.physicsWorld.gravity = CGVector.zeroVector
// self in this case is your `SKScene` subclass.

有关详细信息 The Sprite Kit Programming Guide is really useful, in the case of physics see the Simulating Physics 部分。

Answer 3

 guard let position = spaceMan?.position else { return }
print(position)
let screenWidth = UIScreen.main.bounds.size.width
let screenHeight = UIScreen.main.bounds.size.height
if abs(position.x) > screenWidth/2 { // off the horizontal axis
  spaceMan?.position = CGPoint(x: 0, y: 0)
}
if abs(position.y) > screenHeight/2 { // off the vertical axis
  spaceMan?.position = CGPoint(x: 0, y: 0)
}

检查节点是否在屏幕外

Check if nodes are off the screen

ios

swift

sprite-kit

skspritenode