WebXR Spatial Computing Expert (VR, AR & MR)

English | Bahasa Indonesia

---

<a name="english"></a>

English

Orchestration & Integration

Connects and orchestrates with relevant domain skills:

• web-3d-graphics-expert — WebGPU/WebGL 3D scene rendering, lighting, and model optimization.
• web-game-engine-expert — Spatial physics, grabbing interactions, and fixed-timestep motion.
• apple-ecosystem-expert — Apple Vision Pro visionOS Safari WebXR features and spatial guidelines.
• glsl-shader-expert — Passthrough blending and spatial holographic shaders.
• ui-ux-pro-max — Spatial UI design patterns, world-space HUDs, and gesture-driven navigation.
• anti-slop — Anti-slop spatial ergonomics, zero nauseating jitter, and crisp readable 3D typography.
• performance-web-vitals — Maintaining rock-solid 72/90/120 FPS to prevent simulator sickness.

Description

Production-grade guidance for architecting immersive Virtual Reality (VR), Mixed Reality (MR), and Augmented Reality (AR) in the browser via the WebXR Device API. Covers modern head-mounted displays (Meta Quest 3/3S, Apple Vision Pro) and mobile AR, focusing on Babylon.js and Three.js with @react-three/xr.

Trigger Conditions

Activate this skill when the user is:

• Developing spatial computing web applications or immersive web experiences.
• Setting up WebXR sessions (immersive-vr, immersive-ar).
• Implementing Hand Tracking (joint poses, pinch gestures) or spatial controller interactions.
• Adding Mixed Reality passthrough or depth sensing.
• Implementing AR Hit-Testing to snap 3D models onto real-world planes (floors, walls, tabletops).
• Optimizing XR framerates (fixed foveated rendering) to eliminate motion sickness.

---

Key Capabilities & Headset Targets (2026)

Target Platform	Session Mode	Key Features
Meta Quest 3 / 3S	immersive-vr, immersive-ar	Full-color stereo passthrough, high-precision hand tracking, fixed foveation levels 0-3.
Apple Vision Pro (visionOS)	immersive-vr, immersive-ar	Eye-gaze + pinch interaction, 90/120Hz display refresh, strict privacy hand tracking.
Mobile AR (Android / iOS WebKit)	immersive-ar	Surface hit-testing, ambient light estimation, instant plane detection.

---

1. Babylon.js WebXR Setup (Gold Standard)

Babylon.js provides the most comprehensive out-of-the-box WebXR implementation with integrated teleportation, controller profiles, hand tracking, and hit-testing:

import {
  Scene,
  Vector3,
  MeshBuilder,
  WebXRFeatureName,
  WebXRDefaultExperience,
  IWebXRHitResult
} from '@babylonjs/core';

export async function initBabylonWebXR(scene: Scene) {
  // 1. Initialize Default WebXR Experience with AR + VR fallbacks
  const xr: WebXRDefaultExperience = await scene.createDefaultXRExperienceAsync({
    uiOptions: {
      sessionMode: 'immersive-ar',
      referenceSpaceType: 'local-floor'
    },
    optionalFeatures: ['hit-test', 'hand-tracking', 'anchors', 'plane-detection', 'mesh-detection']
  });

  const fm = xr.baseExperience.featuresManager;

  // 2. Fixed Foveated Rendering: 20-30% GPU saving on Quest 3 / Vision Pro
  fm.enableFeature(WebXRFeatureName.FOVEATION, 'latest', {
    foveationLevel: 2
  });

  // 3. Hand Tracking with Joint & Pinch Detection
  const handTracking = fm.enableFeature(WebXRFeatureName.HAND_TRACKING, 'latest', {
    xrInput: xr.input,
    jointMeshes: {
      invisible: false,
      scaleFactor: 1
    }
  });

  // 4. Real-World Surface Hit-Testing & Reticle Placement
  const marker = MeshBuilder.CreateTorus('reticle', { diameter: 0.15, thickness: 0.02 }, scene);
  marker.isVisible = false;
  marker.rotation.x = Math.PI / 2;

  const hitTest = fm.enableFeature(WebXRFeatureName.HIT_TESTING, 'latest', {
    testOnPointerDownOnly: false
  });

  hitTest.onHitTestResultObservable.add((results: IWebXRHitResult[]) => {
    if (results.length > 0) {
      marker.isVisible = true;
      results[0].transformationMatrix.decompose(
        marker.scaling,
        marker.rotationQuaternion!,
        marker.position
      );
    } else {
      marker.isVisible = false;
    }
  });

  // 5. Spawn object on user tap/pinch
  scene.onPointerDown = () => {
    if (marker.isVisible) {
      const box = MeshBuilder.CreateBox('placedBox', { size: 0.2 }, scene);
      box.position.copyFrom(marker.position);
    }
  };

  return { xr, handTracking, hitTest };
}

---

2. React Three Fiber Setup (@react-three/xr)

import { Canvas } from '@react-three/fiber';
import { XR, createXRStore, Hands, Controllers } from '@react-three/xr';

const store = createXRStore({
  foveation: 1,
  handTracking: true
});

export function SpatialApp() {
  return (
    <>
      <button className="xr-btn" onClick={() => store.enterAR()}>
        Enter Mixed Reality
      </button>
      <Canvas>
        <XR store={store}>
          <ambientLight intensity={0.8} />
          <directionalLight position={[5, 10, 5]} />
          <Controllers />
          <Hands />
          {/* Spatial 3D Objects */}
          <mesh position={[0, 1.2, -1]}>
            <boxGeometry args={[0.3, 0.3, 0.3]} />
            <meshStandardMaterial color="royalblue" />
          </mesh>
        </XR>
      </Canvas>
    </>
  );
}

---

Best Practices for Spatial Performance

1. Rock-Solid Framerates: VR requires stable 72, 90, or 120 FPS. Any frame drop causes instant vestibular nausea.
2. Fixed Foveated Rendering (FFR): Reduces fragment shader resolution in the user's peripheral vision, freeing substantial GPU overhead.
3. No 2D DOM Overlays in VR: Standard HTML elements cannot render inside an immersive session. Render spatial 3D UI panels using world-space 3D meshes or canvas textures.

Sovereign Execution, Token Efficiency & Invariants

Dimension	Sovereign Mandate & Deterministic Contract
Frontier Model Cascade	Medium / High (GPT-5.6 Sol Medium, Gemini 4 Argon, Claude Sonnet 5.5 High, Grok 4.7 High Fast)
Availability Fallback	Gemini 4 Argon/Pro -> Gemini 3.8 Flash; Claude Opus 5.5 -> Claude Opus 4.6 (Zero unhandled missing-model errors)
KV-Cache & Token Protocol	Pin static instructions & schemas at prompt prefix (kv-cache-prefix-optimizer); pass surgical CONTEXT_MAP.md slices (<250 tokens/call) during Swarm Fan-Out
SaaT CLI & MCP Dispatch	CLI: vibes skill exec webxr-ar-vr-expert <audit|eval|verify|generate|blueprint> / MCP: vibes_skill_dispatch, vibes_ast_query, vibes_compile_cache, vibes_optimize_budget, vibes_verify_gate
NFR & Anti-Slop Invariants	P99 API Gateway Latency < 85ms, OpenAPI 3.1 / TypeSpec strict schema parity, RFC 9457 Problem Details error contracts, Idempotency-Key enforcement; 100% complete zero-placeholder output verified via node scripts/check-anti-slop.js --strict

---

---

<a name="bahasa-indonesia"></a>

Bahasa Indonesia

Integrasi Orkestrasi

Terhubung dan mengorkestrasi skill domain yang relevan:

• web-3d-graphics-expert — Rendering scene 3D WebGPU/WebGL, pencahayaan, dan optimasi model.
• web-game-engine-expert — Fisika spasial, interaksi menggenggam objek, dan pergerakan fixed-timestep.
• apple-ecosystem-expert — Fitur WebXR Safari di Apple Vision Pro visionOS dan pedoman spasial.
• glsl-shader-expert — Shader hologram dan blending passthrough AR.
• ui-ux-pro-max — Pola desain UI spasial, HUD world-space, dan navigasi berbasis gestur.
• anti-slop — Ergonomi spasial anti-slop, nol getaran pemicu mual, dan tipografi 3D yang tajam.
• performance-web-vitals — Menjaga kestabilan 72/90/120 FPS demi mencegah motion sickness.

Deskripsi

Panduan produksi untuk membangun aplikasi spasial imersif Virtual Reality (VR), Mixed Reality (MR), dan Augmented Reality (AR) di browser melalui WebXR Device API. Mencakup headset modern (Meta Quest 3/3S, Apple Vision Pro) serta perangkat mobile AR.

Kondisi Pemicu

Aktifkan skill ini ketika pengguna:

• Mengembangkan aplikasi web Spatial Computing (VR/AR/MR).
• Menginisialisasi sesi WebXR (immersive-vr, immersive-ar).
• Mengimplementasikan Hand Tracking (pelacakan sendi tangan, gerakan cubit/pinch) atau kontroler spasial.
• Mengaktifkan Passthrough warna Mixed Reality.
• Menggunakan AR Hit-Testing untuk menempatkan objek 3D di lantai atau meja fisik.
• Mengoptimalkan performa VR dengan Fixed Foveated Rendering (FFR).

---

Panduan Inti Pengembangan Spasial

1. Stabilitas Frame Rate Mutlak:
   • Targetkan 72–90 FPS tanpa toleransi stutter. Pada kacamata VR, keterlambatan frame (latency hitch) langsung memicu rasa mual (motion sickness).
2. Fixed Foveated Rendering (FFR):
   • Aktifkan fitur foveation pada Meta Quest untuk menurunkan resolusi tepi lensa (periferi mata), menghemat 20-30% daya GPU.
3. Antarmuka 3D Spasial (Bukan HTML DOM):
   • Elemen HTML standar tidak dapat ditampilkan di dalam sesi imersif. Buat UI berupa panel 3D melayang (world-space meshes).
4. Hit-Testing untuk AR:
   • Manfaatkan Hit-Test API bawaan WebXR untuk mendeteksi bidang nyata permukaan meja atau lantai secara instan sebelum meletakkan objek 3D.
5. Implementasi Lengkap Babylon.js WebXR (AR/VR/MR):

   import { Scene, MeshBuilder, WebXRFeatureName, WebXRDefaultExperience, IWebXRHitResult } from '@babylonjs/core';
   
   export async function inisialisasiBabylonWebXR(scene: Scene) {
     const xr: WebXRDefaultExperience = await scene.createDefaultXRExperienceAsync({
       uiOptions: { sessionMode: 'immersive-ar', referenceSpaceType: 'local-floor' },
       optionalFeatures: ['hit-test', 'hand-tracking', 'plane-detection', 'mesh-detection']
     });
   
     const fm = xr.baseExperience.featuresManager;
     fm.enableFeature(WebXRFeatureName.FOVEATION, 'latest', { foveationLevel: 2 });
     fm.enableFeature(WebXRFeatureName.HAND_TRACKING, 'latest', { xrInput: xr.input });
   
     const reticle = MeshBuilder.CreateTorus('reticle', { diameter: 0.15, thickness: 0.02 }, scene);
     reticle.isVisible = false;
     reticle.rotation.x = Math.PI / 2;
   
     const hitTest = fm.enableFeature(WebXRFeatureName.HIT_TESTING, 'latest', { testOnPointerDownOnly: false });
     hitTest.onHitTestResultObservable.add((results: IWebXRHitResult[]) => {
       if (results.length > 0) {
         reticle.isVisible = true;
         results[0].transformationMatrix.decompose(reticle.scaling, reticle.rotationQuaternion!, reticle.position);
       } else {
         reticle.isVisible = false;
       }
     });
   
     return { xr, hitTest };
   }
   

Matriks Eksekusi Berdaulat, Efisiensi Token & Invarian

Dimensi	Mandat Berdaulat & Kontrak Deterministik
Kaskade Model Frontier	Medium / High (GPT-5.6 Sol Medium, Gemini 4 Argon, Claude Sonnet 5.5 High, Grok 4.7 High Fast)
Invarian Fallback Ketersediaan	Gemini 4 Argon/Pro -> Gemini 3.8 Flash; Claude Opus 5.5 -> Claude Opus 4.6 (Bebas gagal saat model belum tersedia/kuota penuh)
Protokol Hemat Token & KV-Cache	Kunci instruksi & skema statis di prefix awal (kv-cache-prefix-optimizer); kirim potongan CONTEXT_MAP.md (<250 token/panggilan) saat Fan-Out
Eksekusi SaaT CLI & MCP	CLI: vibes skill exec webxr-ar-vr-expert <audit|eval|verify|generate|blueprint> / MCP: vibes_skill_dispatch, vibes_ast_query, vibes_compile_cache, vibes_optimize_budget, vibes_verify_gate
Invarian NFR & Anti-Slop	Latensi P99 API < 85ms, paritas skema ketat OpenAPI 3.1 / TypeSpec, kontrak error RFC 9457 Problem Details, penegakan Idempotency-Key; kode 100% tuntas tanpa placeholder diverifikasi melalui node scripts/check-anti-slop.js --strict