我正在为我的应用程序使用ARKit,我尝试从我的web服务器(URL)动态加载.scn文件
这是我的代码的一部分
let urlString = "https://da5645f1.ngrok.io/mug.scn"
let url = URL.init(string: urlString)
let request = URLRequest(url: url!)
let session = URLSession.shared
let downloadTask = session.downloadTask(with: request,completionHandler: { (location:URL?,response:URLResponse?,error:Error?)
-> Void in
print("location:\(String(describing: location))")
let locationPath = location!.path
let documents:String = NSHomeDirectory() + "/Documents/mug.scn"
ls = NSHomeDirectory() + "/Documents"
let fileManager = FileManager.default
if (fileManager.fileExists(atPath: documents)){
try! fileManager.removeItem(atPath: documents)
}
try! fileManager.moveItem(atPath: locationPath,toPath: documents)
print("new location:\(documents)")
let node = SCNNode()
let scene = SCNScene(named:"mug.scn",inDirectory: ls)
let nodess = scene?.rootNode.childNode(withName: "Mug",recursively: true)
node.addChildNode(nodess!)
let nodeArray = scene!.rootNode.childNodes
for childNode in nodeArray {
node.addChildNode(childNode as SCNNode)
}
self.addChildNode(node)
self.modelLoaded = true
})
downloadTask.resume()
NSLog的：
location:Optional(file:///private/var/mobile/Containers/Data/Application/A1B996D7-ABE9-4000-91DB-2370076198D5/tmp/CFNetworkDownload_duDlwf.tmp) new location:/var/mobile/Containers/Data/Application/A1B996D7-ABE9-4000-91DB-2370076198D5/Documents/mug.scn
.scn文件下载与上面提到的(新位置)文件路径..但当我尝试在SCNScene中使用此下载文件
let scene = SCNScene(named:"mug.scn",inDirectory: ls)
总是场景值为零.
错误
Thread 4: Fatal error: Unexpectedly found nil while unwrapping an Optional value
如何解决这个问题.谢谢
解决方法
关于init？(named：String),文档说：
Loads a scene from a file with the specified name in the app’s main bundle
因为您在主包中没有这样的文件(来自下载),您可以尝试使用以下构造函数：
init(url: URL,options: [SCNSceneSource.LoadingOption : Any]? = nil)
所以你的代码可能是：
do {
let documents = "yourValidPath"
let scene = try SCNScene(url: URL(fileURLWithPath: documents),options: nil)
} catch {}
