我略微修改了Apple's example关于识别ARKit 1.5中的图像,以便每次识别图像时都会在其前面显示一些文本几何体。
不幸的是我发现当按下StatusView视图中的重置按钮时,我的文本几何体不会被删除,而只会在场景的新中心周围重新定位。
相反,如果我按下后退按钮(因为我将主视图控制器嵌入导航控制器中以便通过按钮启动AR会话而不是像示例中那样自动启动AR会话),然后再次启动会话,然后一切都正确消失。
分析代码我可以确认重置按钮和来自ViewController的来回触发相同的功能如下
func resetTracking() {
guard let referenceImages = loadImageReferences() else {
fatalError("Missing expected asset catalog resources.")
}
let configuration = ARWorldTrackingConfiguration()
configuration.detectionImages = referenceImages
configuration.planeDetection = [.horizontal, .vertical]
session.run(configuration, options: [.resetTracking, .removeExistingAnchors])
statusViewController.scheduleMessage("Look around to detect images", inSeconds: 7.5, messageType: .contentPlacement)
}
正如我所提到的,此函数在ViewController的ViewDidLoad
方法中调用
override func viewDidLoad() {
super.viewDidLoad()
sceneView.delegate = self
sceneView.session.delegate = self
// debug scene to see feature points and world's origin ARSCNDebugOptions.showFeaturePoints,
self.sceneView.debugOptions = [ARSCNDebugOptions.showWorldOrigin]
// Hook up status view controller callback(s).
statusViewController.restartExperienceHandler = { [unowned self] in
self.restartExperience()
}
}
func restartExperience() {
guard isRestartAvailable else { return }
isRestartAvailable = false
statusViewController.cancelAllScheduledMessages()
resetTracking()
// Disable restart for a while in order to give the session time to restart.
DispatchQueue.main.asyncAfter(deadline: .now() + 5.0) {
self.isRestartAvailable = true
}
}
并按下StatusViewController中的重置按钮。
@IBAction private func restartExperience(_ sender: UIButton) {
restartExperienceHandler()
}
var restartExperienceHandler: () -> Void = {}
为了进一步参考,我创建了如下文字
func createBillboardText(text: String, position: SCNNode, width: CGFloat, height: CGFloat){
let newText = splitString(every: 10, string: text)
let textGeometry = SCNText(string: newText, extrusionDepth: 1.0)
textGeometry.firstMaterial!.diffuse.contents = UIColor.red
let textNode = SCNNode(geometry: textGeometry)
// Update object's pivot to its center
// https://stackoverflow.com/questions/44828764/arkit-placing-an-scntext-at-a-particular-point-in-front-of-the-camera
let (min, max) = textGeometry.boundingBox
let dx = min.x + 0.5 * (max.x - min.x)
let dy = min.y + 0.5 * (max.y - min.y)
let dz = min.z + 0.5 * (max.z - min.z)
textNode.pivot = SCNMatrix4MakeTranslation(dx, dy, dz)
textNode.scale = SCNVector3(0.005, 0.005, 0.005)
let plane = SCNPlane(width: width, height: height)
let blueMaterial = SCNMaterial()
blueMaterial.diffuse.contents = UIColor.blue
blueMaterial.transparency = 0
plane.firstMaterial = blueMaterial
let parentNode = SCNNode(geometry: plane) // this node will hold our text node
let yFreeConstraint = SCNBillboardConstraint()
yFreeConstraint.freeAxes = [.Y] // optionally
parentNode.constraints = [yFreeConstraint] // apply the constraint to the parent node
parentNode.addChildNode(textNode)
position.addChildNode(parentNode)
sceneView.autoenablesDefaultLighting = true
}
在func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor)
方法中调用self.createBillboardText(text: message, position: node, width: referenceImage.physicalSize.width, height: referenceImage.physicalSize.height )
我还找到this thread,但我不知道如何在场景中调用该函数。
答案 0 :(得分:2)
我相信您要处理删除SCNNodes
的方式是在resetFunction
中调用以下函数:
self.augmentedRealityView.scene.rootNode.enumerateChildNodes { (existingNode, _) in
existingNode.removeFromParentNode()
}
其中augmentedRealityView
指的是ARSCNView
。
您还可以将特定节点存储在[SCNNode]
数组中,然后遍历它们以删除它们,例如:
for addedNode in nodesAdded{
addedNode.removeFromParentNode()
}
希望它有所帮助...
答案 1 :(得分:1)
如果要删除所有节点,请使用以下命令:
self.sceneView.scene.rootNode.enumerateChildNodes { (node, stop) in
node.removeFromParentNode()
}
现在,如果要删除特定节点,请使用以下命令:
self.sceneView.scene.rootNode.enumerateChildNodes { (node, stop) in
if node.name == "textNode" {
node.removeFromParentNode()
}
}
这些也适用于SCNNode
,而不仅仅是ARSCNView
,这意味着您可以将子节点循环到SCNNode
,而不仅仅是来自场景rootNode
这是我在项目中使用的代码。在这里,我首先删除节点上的所有childNodes
,然后删除SCNNode
本身。然后我继续暂停会话,这将结束它。我运行新会话,最后将worldOrigin重置为当前摄像机位置。如果应用程序的启动角度关闭,形状可能会出错。
sceneView.scene.rootNode.enumerateHierarchy { (node, stop) in
node.childNodes.forEach({
$0.removeFromParentNode()
})
node.removeFromParentNode()
}
sceneView.session.pause()
sceneView.session.run(configuration, options: .resetTracking)
sceneView.session.setWorldOrigin(relativeTransform: matrix)