2nd/10_Wiki/Topics/Domain_Programming/DevOps_and_Security/Alternative Realities.md

id, title, category, status, canonical_id, aliases, duplicate_of, source_trust_level, confidence_score, verification_status, tags, raw_sources, last_reinforced, github_commit, tech_stack

id	title	category	status	canonical_id	aliases	duplicate_of	source_trust_level	confidence_score	verification_status	tags	raw_sources	last_reinforced	github_commit	tech_stack
wiki-2026-0508-alternative-realities	Alternative Realities	10_Wiki/Topics	verified	self	XR Mixed Reality MR/AR/VR Spectrum	none	A	0.9	applied	xr vr ar mr immersive		2026-05-10	applied	language framework TypeScript WebXR/Three.js/Unity

Alternative Realities

매 한 줄

"매 reality 는 spectrum 위 한 점이다.". Milgram 1994 RV continuum 부터 modern XR (Apple Vision Pro M5, Quest 4, Snap Spectacles 6) 까지, alternative realities 는 physical reality 를 augment / replace / blend 하는 매 mediated environment 의 총칭. 2026 의 mainstream 은 passthrough MR + hand tracking + neural input.

매 핵심

매 Reality-Virtuality Continuum

• VR (Virtual Reality): 매 100% synthetic — Quest 4, Vision Pro fully-immersive mode.
• AR (Augmented Reality): 매 real + overlay — phone AR, Snap Spectacles, HoloLens.
• MR (Mixed Reality): 매 real + virtual interact — Vision Pro passthrough, Quest 4 color passthrough.
• XR (Extended Reality): 매 umbrella term — VR/AR/MR all-inclusive.

매 Tech Stack 2026

• Display: micro-OLED 4K/eye, varifocal, foveated rendering.
• Tracking: inside-out 6DoF, eye tracking, hand tracking 26-joint, body pose.
• Input: pinch + gaze (Vision Pro), neural EMG (Meta wristband 2026), voice (Whisper-on-device).
• Compute: Apple M5/Snapdragon XR3 — 매 on-device transformer inference.

매 응용

1. Productivity: Vision Pro virtual displays, Immersed VR coding.
2. Training: surgical sim, military, industrial maintenance.
3. Therapy: VR exposure (PTSD, phobia), pain distraction.
4. Social: Horizon Worlds, VRChat, Rec Room.
5. Industrial Twin: AR overlay on factory equipment.

💻 패턴

WebXR session bootstrap

// Modern WebXR (2026) — immersive-ar with hand tracking
const xr = navigator.xr;
if (await xr.isSessionSupported('immersive-ar')) {
  const session = await xr.requestSession('immersive-ar', {
    requiredFeatures: ['hand-tracking', 'hit-test'],
    optionalFeatures: ['anchors', 'plane-detection', 'mesh-detection'],
  });
  session.addEventListener('end', cleanup);
  await renderer.xr.setSession(session);
}

Hand-tracking pinch gesture

function onXRFrame(time: number, frame: XRFrame) {
  const refSpace = renderer.xr.getReferenceSpace();
  for (const inputSource of frame.session.inputSources) {
    if (!inputSource.hand) continue;
    const thumb = frame.getJointPose(inputSource.hand.get('thumb-tip'), refSpace);
    const index = frame.getJointPose(inputSource.hand.get('index-finger-tip'), refSpace);
    const dist = vec3.distance(thumb.transform.position, index.transform.position);
    if (dist < 0.02) emit('pinch', inputSource.handedness);
  }
}

Passthrough + virtual content (Three.js)

renderer.xr.enabled = true;
renderer.setClearAlpha(0); // 매 transparent — passthrough shows through
scene.background = null;
// 매 virtual cube anchored to detected plane
const anchor = await frame.createAnchor(planePose.transform, refSpace);
scene.add(makeCubeAtAnchor(anchor));

Foveated rendering hint

const layer = xr.glLayer;
layer.fixedFoveation = 0.7; // 매 0=off, 1=max — 매 30% GPU savings

Eye-tracked gaze input

session.requestReferenceSpace('viewer').then(viewerSpace => {
  // 매 Vision Pro / Quest Pro — gaze ray from eye
  const gazePose = frame.getPose(viewerSpace, refSpace);
  raycaster.set(gazePose.transform.position, gazeDirection);
});

매 결정 기준

상황	Approach
Web 배포	WebXR + Three.js
Native iOS	RealityKit + ARKit
Native Android	ARCore + Sceneform/Filament
Cross-platform native	Unity XR / Unreal
Enterprise 산업	Vision Pro / HoloLens 2

기본값: 매 WebXR 시도 → 부족시 native.

🔗 Graph

• 부모: VR 엑서게임 (VR Exergaming) · HMD(Head-Mounted Display) 기반 엑서게임 환경
• 변형: Digital Twins · Digital Twins
• 응용: Beat Saber 엑서게임 연구(Beat Saber Exergaming Study) · Remote-Rehabilitation
• Adjacent: Visual-Effects-VFX

🤖 LLM 활용

언제: XR scene authoring, gesture pattern matching, accessibility caption generation. 언제 X: 매 real-time inner loop (latency budget 11ms) 에서 cloud LLM 호출.

❌ 안티패턴

• VR 멀미 무시: 매 locomotion = teleport/snap-turn 권장. Smooth locomotion 은 매 opt-in.
• 60fps 미만: 매 90fps 미만 = motion sickness. 매 budget 11ms.
• Untracked controllers: 매 always handle controller-lost 이벤트.
• Single-eye render: 매 stereo render 필수 — single-eye 는 depth 깨짐.

🧪 검증 / 중복

• Verified: Milgram & Kishino 1994; W3C WebXR Device API 2024; Apple visionOS 3 docs.
• 신뢰도 A.

🕓 Changelog

날짜	변경
2026-05-08	Phase 1
2026-05-10	Manual cleanup — XR continuum + 2026 stack + WebXR patterns