我想要一个
SKSpriteNode
保持在屏幕上移动,并永远随着边缘反弹。所以我设置了边缘的物理特性:
let borderBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
borderBody.friction = 0
self.physicsBody = borderBody
physicsWorld.gravity = CGVectorMake(0, 0)
然后是精灵的物理:
ball.position = CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame))
ball.size = CGSizeMake(30, 30)
ball.physicsBody = SKPhysicsBody(circleOfRadius: ball.size.width/2)
ball.physicsBody?.allowsRotation = false
ball.physicsBody?.restitution = 1.0
ball.physicsBody?.linearDamping = 0.0
ball.physicsBody?.friction = 0.0
ball.physicsBody?.applyImpulse(CGVectorMake(10, -10))
self.addChild(ball)
问题是,精灵无论如何都不会受到物理的影响,而是停留在屏幕的中央。我做错了什么?