swift - 请帮助我了解 UITouch (SpriteKit)

Question

我想从左侧和右侧创建一个节点，当我触摸它们时，小鸟会飞向左侧或右侧。

1. 首先我创建了一个鸟节点

2. 然后，我创建了测试节点

   var groundleft = SKSpriteNode()
   groundleft.position = CGPoint(x: 0, y: 50)
   groundleft.size = CGSize(width: 500, height: 100)
   groundleft.color = UIColor(red: 7, green: 5, blue: 7, alpha: 20)
   
   
   groundleft.physicsBody = SKPhysicsBody(rectangleOfSize:    CGSizeMake(self.size.width, 100))
   groundleft.physicsBody?.dynamic = false
   groundleft.zPosition = 0.5
   
   groundleft.name = "toleft"
   

3. 然后我实现了touchesBegan

   override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
   
   
   let touch = touches.first as! UITouch
   let touchLocation = touch.locationInNode(self)
   let touchedNode = self.nodeAtPoint(touchLocation)
   
   if(touchedNode.name == "toleft"){
   
       bird.physicsBody?.velocity = CGVectorMake(0, 0)
       bird.physicsBody?.applyImpulse(CGVectorMake(-10, 100))
   
     }
   }
   

为什么不起作用？？

Answer 1

您遇到问题的原因是物理主体的动态属性设置为 false。

您需要设置

groundleft.physicsBody?.dynamic = true //Or remove this line, as dynamic is true by default

您可以阅读有关动态属性的更多信息here 。如文档中所示:

The default value is YES. If the value is NO, the physics body ignores all forces and impulses applied to it. This property is ignored on edge-based bodies; they are automatically static.

您可能已将dynamic 设置为 false，因为节点可能会由于物理世界的重力而掉落。为了解决这个问题，您可以设置物理主体的 affectedByGravity 属性，或者完全更改场景的物理世界的 gravity 属性。