Question

以下代码会导致rotateLayer物理机构在几秒钟后从屏幕上掉下来。然而，评论圈子物理主体会在屏幕上保留rotateLayer。是否无法将物理主体添加到节点，然后旋转父节点？从概念上讲，目标是围绕固定点as described here旋转圆，但是将物理主体附加到圆上，同时还通过角速度控制旋转，而不是zRotation。

let size = CGSize(width: 10, height: 250)
rotateLayer = SKNode()
gameLayer.addChild(rotateLayer)

let circleSize = CGSize(width: 10, height: 10)
let circle = SKSpriteNode(color: SKColor.whiteColor(), size: circleSize)
circle.position = CGPoint(x: 0, y: size.height/2 + circleSize.height/2)
circle.physicsBody = SKPhysicsBody(rectangleOfSize: circleSize)
circle.physicsBody?.affectedByGravity = false
circle.physicsBody?.friction = 0
circle.physicsBody?.linearDamping = 0
circle.physicsBody?.angularDamping = 0
circle.physicsBody?.collisionBitMask = 0
circle.physicsBody?.dynamic = false

rotateLayer.addChild(circle)

rotateLayer.physicsBody = SKPhysicsBody(rectangleOfSize: size)
rotateLayer.physicsBody?.affectedByGravity = false
rotateLayer.physicsBody?.friction = 0
rotateLayer.physicsBody?.linearDamping = 0
rotateLayer.physicsBody?.angularDamping = 0
rotateLayer.physicsBody?.angularVelocity = -3.0

Answer 1

添加rotateLayer.collisionBitMask = 0解决了问题。不知道为什么。

SpriteKit：添加另一个物理体时，旋转SKNode会从屏幕上掉下来

1 个答案: