ARKit – 如何实现 SCNRenderer().audioListener？

Question

我正在尝试在我的应用程序中实现这个新的位置音频。

我用一个 tapGesture 在我的场景中插入一个 Drone，然后我将 sound.mp3 附加到它上面

    func tapToPlace(node: SCNNode, recognizer: UITapGestureRecognizer, view : ARSCNView){
        debugPrint("tap")
        if gameState == .placeObject {
                DispatchQueue.global().async {
                    let tapedScreen = recognizer.location(in: view)
                    guard let query = view.raycastQuery(from: tapedScreen, allowing: .existingPlaneGeometry, alignment: .horizontal) else {return}
                    let result = view.session.raycast(query).first
                    
                    guard let worldTransform = result?.worldTransform else {return}// simd_Float4x4
                    let newNode = node.clone() // duplicate the node create at app start up
                    newNode.position = SCNVector3(worldTransform.columns.3.x, worldTransform.columns.3.y, worldTransform.columns.3.z) // place it at position tapped
                    
                    // set up position audio
                    let audio = SCNAudioSource(fileNamed: "sound.mp3")! // add audio file
                    audio.loops = true
                    audio.volume = 0.3
                    audio.rate = 0.1
                    audio.isPositional = true
                    audio.shouldStream = false
                    audio.load()
                    let player = SCNAudioPlayer(source: audio)
                    newNode.addAudioPlayer(player)
                    
                    view.scene.rootNode.addChildNode(newNode)
                    
                }
            
        }
    }

阅读苹果文档看起来需要实现这个audioListner: SCNnode

我该怎么做？

我尝试了以下方法：

我得到了相机的当前位置。

func trackCameraLocation(arView: ARSCNView) -> simd_float4x4 {
            var cameraloc : simd_float4x4!
            if let camera = arView.session.currentFrame?.camera.transform {
                cameraloc = camera
            }
            return cameraloc
        }

我用这个里面的方法做update frame，为了得到准确的用户位置。

func session(_ session: ARSession, didUpdate frame: ARFrame) {
            cameraLocation = trackCameraLocation(arView: sceneView)
        }

一旦我有了相机位置，在方法 didAdd 节点内我尝试设置 audioListner..

func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
            let cameraNode = SCNNode()
            cameraNode.position = SCNVector3(cameraLocation.columns.3.x, cameraLocation.columns.3.y, cameraLocation.columns.3.z)
            
            renderer.audioListener = cameraNode
        }

但是.. 没有任何效果.. 听不到任何声音.. 我只看到我的无人机在我家的地板上保持沉默。

寻求一些帮助或解释如何实现这个新的 ARKit 未来。

提前感谢您的帮助。

我放音频文件的地方：

Answer 1

试试这个解决方案。它适用于 VR 应用和 AR 应用。

import SceneKit

extension ViewController: SCNSceneRendererDelegate {

    func renderer(_ renderer: SCNSceneRenderer, 
           updateAtTime time: TimeInterval) {

        listener.position.z = -20  // change listener's position here
        renderer.audioListener = self.listener
    }
}

...

class ViewController: UIViewController {
    
    let scene = SCNScene()
    let audioNode = SCNNode()
    let listener = SCNNode()

    override func viewDidLoad() {
        super.viewDidLoad()    
        let sceneView = self.view as! SCNView
        sceneView.scene = self.scene
        sceneView.backgroundColor = .black
        sceneView.delegate = self
        
        let node = SCNNode()
        node.geometry = SCNSphere(radius: 0.05)
        node.position = SCNVector3(0,0,-2)
        self.scene.rootNode.addChildNode(node)
        
        let path = Bundle.main.path(forResource: "art.scnassets/audio",
                                         ofType: "mp3")      // MONO AUDIO
        let url = URL(fileURLWithPath: path!)
        let source = SCNAudioSource(url: url)!
        source.isPositional = true
        source.shouldStream = false
        source.load()
        let player = SCNAudioPlayer(source: source)                 
        node.addChildNode(audioNode)
        
        // THE LOCATION OF THIS LINE IS IMPORTANT
        audioNode.addAudioPlayer(player)
        audioNode.addChildNode(self.listener)
    }
}