为什么 SCNNode 会“摇晃"?什么时候掉到 SCNPlane 上? [英] Why is SCNNode "jiggling" when dropped onto SCNPlane?
问题描述
我有一个 SCNPlane，当检测到水平表面有足够的区域时，它会添加到场景中.根据放置的地板/桌子，飞机似乎被放置在正确的位置.问题是当我将一个 SCNNode(无论是盒子、金字塔、3D 模型等)放到飞机上时，它最终会找到一个着陆点，99% 的人开始疯狂地摇晃.很少有它只是降落而根本没有移动.我也认为这可能是由于节点掉落并降落在平面表面下方.它既不是顶部"也不是低于"平面.可能是因为节点在两个级别之间摇摇欲坠，所以它吓坏了?
I have a SCNPlane that is added to the scene when a sufficient area is detected for a horizontal surface. The plane appears to be placed in a correct spot, according to the floor/table it's being placed on. The problem is when I drop a SCNNode(this has been consistent whether it was a box, pyramid, 3D-model, etc.) onto the plane, it will eventually find a spot to land and 99% start jiggling all crazy. Very few times has it just landed and not moved at all. I also think this may be cause by the node being dropped and landing slightly below the plane surface. It is not "on top" neither "below" the plane. Maybe the node is freaking out because it's kind of teetering between both levels?
这是正在发生的事情的视频，您可以在开头看到盒子在飞机的下方和上方，橙色盒子在与深蓝色盒子碰撞时确实停止了，但确实回到了它的摇晃方式当绿色框最后与它碰撞时:
Here is a video of what's going on, you can see at the beginning that the box is below and above the plane and the orange box does stop when it collides with the dark blue box, but does go back to its jiggling ways when the green box collides with it at the end:
代码位于 github
我也会展示一些嵌入代码的相关部分:
I will also show some of the relevant parts embedded in code:
我只是创建了一个 Plane 类以在需要时添加到场景中
I just create a Plane class to add to the scene when I need to
class Plane: SCNNode {
var anchor :ARPlaneAnchor
var planeGeometry :SCNPlane!
init(anchor :ARPlaneAnchor) {
self.anchor = anchor
super.init()
setup()
}
func update(anchor: ARPlaneAnchor) {
self.planeGeometry.width = CGFloat(anchor.extent.x)
self.planeGeometry.height = CGFloat(anchor.extent.z)
self.position = SCNVector3Make(anchor.center.x, 0, anchor.center.z)
let planeNode = self.childNodes.first!
planeNode.physicsBody = SCNPhysicsBody(type: .static, shape: SCNPhysicsShape(geometry: self.planeGeometry, options: nil))
}
private func setup() {
//plane dimensions
self.planeGeometry = SCNPlane(width: CGFloat(self.anchor.extent.x), height: CGFloat(self.anchor.extent.z))
//plane material
let material = SCNMaterial()
material.diffuse.contents = UIImage(named: "tronGrid.png")
self.planeGeometry.materials = [material]
//plane geometry and physics
let planeNode = SCNNode(geometry: self.planeGeometry)
planeNode.physicsBody = SCNPhysicsBody(type: .static, shape: SCNPhysicsShape(geometry: self.planeGeometry, options: nil))
planeNode.physicsBody?.categoryBitMask = BodyType.plane.rawValue
planeNode.position = SCNVector3Make(anchor.center.x, 0, anchor.center.z)
planeNode.transform = SCNMatrix4MakeRotation(Float(-Double.pi / 2.0), 1, 0, 0)
//add plane node
self.addChildNode(planeNode)
}
这是视图控制器
enum BodyType: Int {
case box = 1
case pyramid = 2
case plane = 3
}
class ViewController: UIViewController, ARSCNViewDelegate, SCNPhysicsContactDelegate {
//outlets
@IBOutlet var sceneView: ARSCNView!
//globals
var planes = [Plane]()
var boxes = [SCNNode]()
//life cycle
override func viewDidLoad() {
super.viewDidLoad()
//set sceneView's frame
self.sceneView = ARSCNView(frame: self.view.frame)
//add debugging option for sceneView (show x, y , z coords)
self.sceneView.debugOptions = [ARSCNDebugOptions.showFeaturePoints, ARSCNDebugOptions.showWorldOrigin]
//give lighting to the scene
self.sceneView.autoenablesDefaultLighting = true
//add subview to scene
self.view.addSubview(self.sceneView)
// Set the view's delegate
sceneView.delegate = self
//subscribe to physics contact delegate
self.sceneView.scene.physicsWorld.contactDelegate = self
//show statistics such as fps and timing information
sceneView.showsStatistics = true
//create new scene
let scene = SCNScene()
//set scene to view
sceneView.scene = scene
//setup recognizer to add scooter to scene
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(tapped))
sceneView.addGestureRecognizer(tapGestureRecognizer)
}
//MARK: helper funcs
@objc func tapped(recognizer: UIGestureRecognizer) {
let scnView = recognizer.view as! ARSCNView
let touchLocation = recognizer.location(in: scnView)
let touch = scnView.hitTest(touchLocation, types: .existingPlaneUsingExtent)
//take action if user touches box
if !touch.isEmpty {
guard let hitResult = touch.first else { return }
addBox(hitResult: hitResult)
}
}
private func addBox(hitResult: ARHitTestResult) {
let boxGeometry = SCNBox(width: 0.1,
height: 0.1,
length: 0.1,
chamferRadius: 0)
let material = SCNMaterial()
material.diffuse.contents = UIColor(red: .random(),
green: .random(),
blue: .random(),
alpha: 1.0)
boxGeometry.materials = [material]
let boxNode = SCNNode(geometry: boxGeometry)
//adding physics body, a box already has a shape, so nil is fine
boxNode.physicsBody = SCNPhysicsBody(type: .dynamic, shape: nil)
//set bitMask on boxNode, enabling objects with diff categoryBitMasks to collide w/ each other
boxNode.physicsBody?.categoryBitMask = BodyType.plane.rawValue | BodyType.box.rawValue
boxNode.position = SCNVector3(hitResult.worldTransform.columns.3.x,
hitResult.worldTransform.columns.3.y + 0.3,
hitResult.worldTransform.columns.3.z)
self.sceneView.scene.rootNode.addChildNode(boxNode)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
let configuration = ARWorldTrackingConfiguration()
configuration.planeDetection = .horizontal
//track objects in ARWorld and start session
sceneView.session.run(configuration)
}
//MARK: - ARSCNViewDelegate
func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
//if no anchor found, don't render anything!
if !(anchor is ARPlaneAnchor) {
return
}
DispatchQueue.main.async {
//add plane to scene
let plane = Plane(anchor: anchor as! ARPlaneAnchor)
self.planes.append(plane)
node.addChildNode(plane)
//add initial scene object
let pyramidGeometry = SCNPyramid(width: CGFloat(plane.planeGeometry.width / 8), height: plane.planeGeometry.height / 8, length: plane.planeGeometry.height / 8)
pyramidGeometry.firstMaterial?.diffuse.contents = UIColor.white
let pyramidNode = SCNNode(geometry: pyramidGeometry)
pyramidNode.name = "pyramid"
pyramidNode.physicsBody = SCNPhysicsBody(type: .dynamic, shape: nil)
pyramidNode.physicsBody?.categoryBitMask = BodyType.pyramid.rawValue | BodyType.plane.rawValue
pyramidNode.physicsBody?.contactTestBitMask = BodyType.box.rawValue
pyramidNode.position = SCNVector3(-(plane.planeGeometry.width) / 3, 0, plane.planeGeometry.height / 3)
node.addChildNode(pyramidNode)
}
}
func renderer(_ renderer: SCNSceneRenderer, didUpdate node: SCNNode, for anchor: ARAnchor) {
let plane = self.planes.filter {
plane in return plane.anchor.identifier == anchor.identifier
}.first
if plane == nil {
return
}
plane?.update(anchor: anchor as! ARPlaneAnchor)
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
//pause session
sceneView.session.pause()
}
}
推荐答案
我想我遵循了相同的教程.我也有同样的结果.原因是因为当立方体从更高的地方落下时，它会加速，并没有准确地击中平面而是通过了.如果将立方体缩小到1 毫米"，您可以看到盒子完全穿过平面并继续落在平面下方.
您可以尝试从离平面较近的地方放下立方体，盒子掉落较慢，并且不会发生这种摇晃".或者您可以尝试使用高度较小的盒子而不是平面.
I think i followed the same tutorial. I also had same result. Reason is because when the cube drops from higher place, it accelerates and doesnot exactly hit on the plane but passes through. If you scale down the cube to '1 mm' you can see box completely passes through plane and continue falling below plane.
You can try droping cube from nearer to the plane, box drops slower and this 'jiggling' will not occur. Or you can try with box with small height instead of plane.
这篇关于为什么 SCNNode 会“摇晃"?什么时候掉到 SCNPlane 上?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
