SceneKit技术问题：如何将ARSCNView视频流设为SCNGeometry纹理

你的代码存在几个核心问题，导致飞船无法显示AR视频流：

• 创建了ARSCNView但未将其添加到视图层级，也没有启动AR会话，摄像头视频流根本没有开始采集
• 当前代码使用普通SCNView而非ARSCNView，无法获取AR摄像头的实时视频源
• 直接赋值arView.scene.background.contents无效，未初始化的ARView背景内容为空，材质因此显示白色

1. 替换视图类型为ARSCNView #

将控制器根视图改为ARSCNView，确保能获取AR摄像头流。

2. 正确初始化并启动AR会话 #

将ARSCNView添加到视图层级，配置并启动AR世界跟踪会话。

3. 正确绑定AR视频流到材质 #

直接将ARSCNView作为材质的diffuse.contents，利用其自带的摄像头画面输出能力。

import UIKit
import SceneKit
import ARKit

class GameViewController: UIViewController, ARSCNViewDelegate {

    private var arView: ARSCNView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 初始化ARSCNView并设置为根视图
        arView = ARSCNView(frame: view.bounds)
        arView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        view.addSubview(arView)
        
        // 配置并启动AR会话
        let configuration = ARWorldTrackingConfiguration()
        arView.session.run(configuration)
        arView.delegate = self
        
        // 加载场景
        let scene = SCNScene(named: "art.scnassets/ship.scn")!
        arView.scene = scene
        
        // 移除自定义相机，使用ARSCNView内置的AR相机
        scene.rootNode.childNodes.filter { $0.camera != nil }.forEach { $0.removeFromParentNode() }
        
        // 添加灯光（保留原有逻辑）
        let lightNode = SCNNode()
        lightNode.light = SCNLight()
        lightNode.light!.type = .omni
        lightNode.position = SCNVector3(x: 0, y: 10, z: 10)
        scene.rootNode.addChildNode(lightNode)
        
        let ambientLightNode = SCNNode()
        ambientLightNode.light = SCNLight()
        ambientLightNode.light!.type = .ambient
        ambientLightNode.light!.color = UIColor.darkGray
        scene.rootNode.addChildNode(ambientLightNode)
        
        // 获取飞船节点并绑定AR视频流材质
        if let ship = scene.rootNode.childNode(withName: "shipMesh", recursively: true),
           let material = ship.geometry?.firstMaterial {
            material.diffuse.contents = arView
            material.lightingModel = .constant
        }
        
        // 配置视图属性
        arView.allowsCameraControl = true
        arView.showsStatistics = true
        arView.backgroundColor = .black
        
        // 添加点击手势
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap(_:)))
        arView.addGestureRecognizer(tapGesture)
    }
    
    @objc
    func handleTap(_ gestureRecognize: UIGestureRecognizer) {
        let p = gestureRecognize.location(in: arView)
        let hitResults = arView.hitTest(p, options: [:])
        
        guard let result = hitResults.first,
              let material = result.node.geometry?.firstMaterial else { return }
        
        SCNTransaction.begin()
        SCNTransaction.animationDuration = 0.5
        
        SCNTransaction.completionBlock = {
            SCNTransaction.begin()
            SCNTransaction.animationDuration = 0.5
            material.emission.contents = UIColor.black
            SCNTransaction.commit()
        }
        
        material.emission.contents = UIColor.red
        SCNTransaction.commit()
    }
    
    override var shouldAutorotate: Bool { true }
    override var prefersStatusBarHidden: Bool { true }
    
    override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
        UIDevice.current.userInterfaceIdiom == .phone ? .allButUpsideDown : .all
    }
}

• 替换视图为ARSCNView：确保能获取AR摄像头实时视频流，同时将其添加到视图层级并启动会话
• 移除自定义相机：ARSCNView自带AR相机，无需手动添加静态相机节点，避免视角冲突
• 绑定ARView到材质：直接将arView作为材质内容，ARSCNView会自动将摄像头画面作为纹理输出
• 启动AR会话：通过ARWorldTrackingConfiguration启动世界跟踪，确保摄像头开始采集画面

内容的提问来源于stack exchange，提问作者Mane Manero