ARKit 3 + SceneKit で People Occlusion を実現する

import UIKit
import SceneKit
import ARKit

class ViewController: UIViewController, ARSCNViewDelegate {

    @IBOutlet var sceneView: ARSCNView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Set the view's delegate
        sceneView.delegate = self

        // Show statistics such as fps and timing information
        sceneView.showsStatistics = true

        // シーンを生成
        let scene = SCNScene()

        // Set the scene to the view
        sceneView.scene = scene

    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        // Create a session configuration
        let configuration = ARWorldTrackingConfiguration()

        // 環境マッピングを有効にする
        configuration.environmentTexturing = .automatic

        // People Occlusion が使える端末か判定
        var message:String;
        if ARWorldTrackingConfiguration.supportsFrameSemantics(.personSegmentationWithDepth) {
            // People Occlusion を使用する
            configuration.frameSemantics = .personSegmentationWithDepth
            message = "Ok! This device supports people occulusion."
        } else {
            message = "No! This device don't support people occulusion."
        }
        print("\(message)")

        // 表示するテキストを用意
        let depth:CGFloat = 0.2 // テキストの厚さ0.2m
        let text = SCNText(string: message, extrusionDepth: depth)
        text.font = UIFont.systemFont(ofSize: 1.0)

        // テキストの色と質感を用意
        let m1 = SCNMaterial()
        m1.diffuse.contents = UIColor.red // 前面に赤色
        // 鏡面反射感を出す
        m1.lightingModel = .physicallyBased
        m1.metalness.contents = 1.0
        m1.metalness.intensity = 1.0
        m1.roughness.intensity = 0.0
        // back material
        let m2 = SCNMaterial()
        m2.diffuse.contents = UIColor.green // 背面に緑色
        m2.lightingModel = .physicallyBased
        m2.metalness.contents = 1.0
        m2.metalness.intensity = 1.0
        m2.roughness.intensity = 0.0
        // extruded sides material
        let m3 = SCNMaterial()
        m3.diffuse.contents = UIColor.blue // 側面に青色
        m3.lightingModel = .physicallyBased
        m3.metalness.contents = 1.0
        m3.metalness.intensity = 1.0
        m3.roughness.intensity = 0.0
        text.materials = [m1, m2, m3] // テキストの色と質感をセット

        // テキストノード作成して、配置する場所を決める
        let textNode = SCNNode(geometry: text)
        textNode.position = SCNVector3(-0.5, -1.5, -0.5)

        // AR空間にテキストノードを追加
        sceneView.scene.rootNode.addChildNode(textNode)

        // Run the view's session
        sceneView.session.run(configuration)
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)

        // Pause the view's session
        sceneView.session.pause()
    }
}