AR/VR/XR TechnologyAR/VR/XR 기술

현실 ───────────────────────────── 가상
   │  AR (증강현실) │ MR (혼합현실) │ VR (가상현실) │

   AR: 현실 위에 2D/3D 오버레이 (포켓몬GO, ARKit)
   MR: 가상 객체가 현실과 물리적으로 상호작용 (HoloLens)
   VR: 완전한 가상 몰입 환경 (Meta Quest, PS VR2)
   XR: AR+MR+VR 통합 개념

import ARKit
import RealityKit

class ARViewController: UIViewController {
    @IBOutlet var arView: ARView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // 평면 감지 AR 세션
        let config = ARWorldTrackingConfiguration()
        config.planeDetection = [.horizontal, .vertical]
        config.environmentTexturing = .automatic
        arView.session.run(config)

        // 탭으로 3D 객체 배치
        let tapGesture = UITapGestureRecognizer(
            target: self, action: #selector(handleTap))
        arView.addGestureRecognizer(tapGesture)
    }

    @objc func handleTap(_ recognizer: UITapGestureRecognizer) {
        let location = recognizer.location(in: arView)
        let results = arView.raycast(
            from: location, allowing: .estimatedPlane, alignment: .horizontal)

        if let result = results.first {
            let anchor = AnchorEntity(world: result.worldTransform)
            let box = ModelEntity(mesh: .generateBox(size: 0.1),
                                  materials: [SimpleMaterial(color: .blue, isMetallic: true)])
            anchor.addChild(box)
            arView.scene.addAnchor(anchor)
        }
    }
}

// WebXR Device API
async function startVR() {
    if (!navigator.xr) return;
    const session = await navigator.xr.requestSession('immersive-vr',
        { requiredFeatures: ['local-floor', 'bounded-floor'] });

    const referenceSpace = await session.requestReferenceSpace('local-floor');
    const glLayer = new XRWebGLLayer(session, gl);
    session.updateRenderState({ baseLayer: glLayer });

    session.requestAnimationFrame(onXRFrame);
}

function onXRFrame(time, frame) {
    const pose = frame.getViewerPose(referenceSpace);
    for (const view of pose.views) {
        // view.projectionMatrix, view.transform으로 렌더링
        renderEye(view);
    }
    session.requestAnimationFrame(onXRFrame);
}