ios - LinearGravityField() 不影响场景 SceneKit 中的物理体

Question

我正在尝试使用 SCNPhysicsField.linearGravityField 对象仅影响场景中的特定对象。问题是，我似乎无法让它影响任何事情。以下是我的 Swift 代码示例:

let downGravityCatagory = 1 << 0
let fieldDown = SCNPhysicsField.linearGravityField()
let fieldUp = SCNPhysicsField.linearGravityField()
let fieldNode = SCNNode()

let sceneView = view as! SCNView
sceneView.scene = scene
sceneView.scene!.physicsWorld.gravity = SCNVector3(x: 0, y: 0, z: 0)

fieldDown.categoryBitMask = downGravityCatagory
fieldDown.active = true
fieldDown.strength = 3
fieldNode.physicsField = fieldDown
scene.rootNode.addChildNode(fieldNode)

var dice = SCNNode()
//I then attach geometry here
dice.physicsBody = SCNPhysicsBody(type: SCNPhysicsBodyType.Dynamic, shape: SCNPhysicsShape(geometry: dice.geometry!, options: nil))
dice.physicsBody?.categoryBitMask = downGravityCatagory
scene.rootNode.addChildNode(dice)

尽管物理体被分配了与重力场相同的类别BitMask，但它们只是以零重力漂浮在那里，仅受物理世界重力的影响。

Answer 1

在节点上设置“downGravityCatagory”位掩码:

dice.categoryBitMask = downGravityCatagory;

物理的categoryBitMask仅用于物理碰撞。