Web Game Engine Expert (Physics & ECS)

English | Bahasa Indonesia

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English

Orchestration & Integration

Connects and orchestrates with relevant domain skills like brainstorming, zero-to-prod-orchestrator, and project-context-mapper to ensure cohesive execution.

Description

Production-grade guidance for building highly interactive 3D simulations and web games. Focuses on integrating modern WebAssembly-based Physics Engines (Havok, Rapier, Cannon-es) and structuring application state using the Entity Component System (ECS) pattern (e.g., bitECS, Miniplex).

Trigger Conditions

Activate this skill when the user is:

• Adding physics (gravity, collisions, rigid bodies) to a 3D scene (Three.js/Babylon.js).
• Dealing with performance issues in web games with thousands of objects.
• Structuring a complex game or simulation architecture.
• Using @dimforge/rapier3d, havok, or cannon-es.

Core Concepts

1. Physics Engine Integration

Avoid calculating collisions manually in JavaScript. Use a dedicated physics engine.

• Babylon.js + Havok: Babylon.js natively supports Havok Physics (the same engine used in AAA titles like Zelda BotW).
• Three.js / React Three Fiber + Rapier: Use @react-three/rapier for seamless integration in R3F. It is written in Rust and compiled to WebAssembly.

// React Three Fiber + Rapier Example
import { Physics, RigidBody } from '@react-three/rapier';

function GameScene() {
  return (
    <Physics gravity={[0, -9.81, 0]}>
      {/* Falling Object */}
      <RigidBody colliders="box" position={[0, 10, 0]}>
        <mesh>
          <boxGeometry />
          <meshStandardMaterial color="hotpink" />
        </mesh>
      </RigidBody>

      {/* Static Floor */}
      <RigidBody type="fixed" colliders="cuboid">
        <mesh position={[0, -1, 0]}>
          <boxGeometry args={[10, 1, 10]} />
          <meshStandardMaterial color="gray" />
        </mesh>
      </RigidBody>
    </Physics>
  );
}

2. Entity Component System (ECS)

Traditional Object-Oriented Programming (OOP) can cause performance bottlenecks in games due to poor cache locality. ECS stores data in contiguous memory arrays (Components) and processes them in tight loops (Systems).

• Use bitECS for extreme performance (uses TypedArrays).
• Use Miniplex for an easier, developer-friendly React integration.

Best Practices

• Decouple Logic from Rendering: The physics engine should update at a fixed timestep (e.g., 60Hz), while rendering should happen at the screen's refresh rate (e.g., 144Hz) using interpolation to prevent stuttering.
• Use Simple Colliders: Never use complex mesh colliders (Convex/Trimesh) for moving objects unless absolutely necessary. Use primitives (Spheres, Boxes, Capsules).

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Integration with Other Skills (MANDATORY)

This skill works best when combined with:

• web-3d-graphics-expert — For the visual rendering of the physics world.
• webxr-ar-vr-expert — For adding grabbable physics objects in VR space.
• realtime-collaboration-expert — For synchronizing physics state across multiple players using WebRTC.

Referenced By Orchestrators (MANDATORY)

• brainstorming — Add to "3D & Graphics" or "Game Development".
• zero-to-prod-orchestrator — Phase 5 (Frontend / Simulation).

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Bahasa Indonesia

Integrasi Orkestrasi

Terhubung dan mengorkestrasi skill domain yang relevan seperti brainstorming, zero-to-prod-orchestrator, dan project-context-mapper untuk memastikan eksekusi yang kohesif.

Deskripsi

Panduan pengembangan game dan simulasi 3D di web. Mencakup integrasi Physics Engine berbasis WebAssembly (Rapier, Havok, Cannon) dan arsitektur Entity Component System (ECS).

Kondisi Pemicu

• Saat menambahkan gravitasi, tabrakan (collision), atau benda padat (rigid body) ke dalam aplikasi 3D.
• Saat membuat game web yang membutuhkan performa tinggi dengan ribuan entitas.

Panduan Singkat

• Pilih Mesin Fisika: Gunakan Havok jika menggunakan Babylon.js. Gunakan Rapier (@react-three/rapier) jika menggunakan Three.js/R3F.
• Gunakan Collider Sederhana: Untuk objek bergerak, selalu gunakan primitive colliders (Kotak, Bola, Kapsul) alih-alih mesh collider agar perhitungan CPU/WASM tetap ringan.
• Pola ECS (Entity Component System): Untuk game kompleks, pisahkan logika dan data menggunakan arsitektur ECS (seperti miniplex atau bitECS) untuk memaksimalkan performa cache memori.