Question

我有一个运行中的简单HTTP服务器，我试图从我的本地服务器中获取此Scenekit，但它向我显示NIL错误或错误加载场景。我不明白如何从我的简单本地主机加载此模型。如何配置我的代码，以便能够从远程或本地服务器获取任何Scenekit。

预先感谢

  do {
                let shipScene = try SCNScene(url: URL(fileURLWithPath: "http://localhost:8080/chair.scn") , options: nil)



            // Set the scene to the view
            sceneView.scene = shipScene
            let shipNode = shipScene.rootNode.childNodes.first!
            shipNode.position = SCNVector3Zero
            shipNode.position.z = 0.15
            shipNode.position.y = 0
            shipNode.position.x = 0
            let action = SCNAction.repeatForever(SCNAction.rotate(by: .pi, around: SCNVector3(0, 1, 0), duration: 5))
            shipNode.runAction(action)
            planeNode.addChildNode(shipNode)
            node.addChildNode(planeNode)

        } catch {
            print("ERROR loading scene")
        }

Answer 1

正如@Prashant所说，在使用它之前，您需要先下载模型。

因此，您需要做的第一件事就是创建一个URLSession来下载文件，例如：

/// Downloads An SCNFile From A Remote URL
func downloadSceneTask(){

        //1. Get The URL Of The SCN File
        guard let url = URL(string: "http://localhost:8080/chair.scn") else { return }

        //2. Create The Download Session
        let downloadSession = URLSession(configuration: URLSession.shared.configuration, delegate: self, delegateQueue: nil)

        //3. Create The Download Task & Run It
        let downloadTask = downloadSession.downloadTask(with: url)
        downloadTask.resume()      
    }

 }

然后我们将参考URLSessionDownloadDelegate，例如：

class ViewController: UIViewController, URLSessionDownloadDelegate { }

现在我们已将代表连接起来，我们需要使用以下callback将下载的文件复制到设备的Documents Directory：

func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didFinishDownloadingTo location: URL) {

    //1. Create The Filename
    let fileURL = getDocumentsDirectory().appendingPathComponent("chair.scn")

    //2. Copy It To The Documents Directory
    do {
        try FileManager.default.copyItem(at: location, to: fileURL)

        print("Successfuly Saved File \(fileURL)")

        //3. Load The Model
        loadModel()

    } catch {

        print("Error Saving: \(error)")
    }

}

请注意，在函数中，我正在使用以下帮助程序方法来获取文档目录：

/// Returns The Documents Directory
///
/// - Returns: URL
func getDocumentsDirectory() -> URL {

let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
let documentsDirectory = paths[0]
return documentsDirectory

}

一旦文件被下载并复制到整个文件中，我们将像这样调用loadModel function（3）：

/// Loads The SCNFile From The Documents Directory
func loadModel(){

    //1. Get The Path Of The Downloaded File
    let downloadedScenePath = getDocumentsDirectory().appendingPathComponent("chair.scn")

    do {

        //2. Load The Scene Remembering The Init Takes ONLY A Local URL
        let modelScene =  try SCNScene(url: downloadedScenePath, options: nil)

        //3. Create A Node To Hold All The Content
        let modelHolderNode = SCNNode()

        //4. Get All The Nodes From The SCNFile
        let nodeArray = modelScene.rootNode.childNodes

        //5. Add Them To The Holder Node
        for childNode in nodeArray {
            modelHolderNode.addChildNode(childNode as SCNNode)
        }

        //6. Set The Position
        modelHolderNode.position = SCNVector3(0, 0, -1.5)

        //7. Add It To The Scene
        self.augmentedRealityView?.scene.rootNode.addChildNode(modelHolderNode)


    } catch  {
        print("Error Loading Scene")
    }

}

希望有帮助...

从URL Xcode快速加载3d资产

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