threejs-builder

تایید شده

Create simple, performant Three.js web apps/scenes (JS/TS, ES modules): scene/camera/renderer setup, lighting, geometries, materials, animation loop, resizing, OrbitControls, GLTF/GLB loading, and practical performance guardrails.

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نصب مهارت

مهارت‌ها کدهای شخص ثالث از مخازن عمومی GitHub هستند. SkillHub الگوهای مخرب شناخته‌شده را اسکن می‌کند اما نمی‌تواند امنیت را تضمین کند. قبل از نصب، کد منبع را بررسی کنید.

نصب سراسری (سطح کاربر):

npx skillhub install chongdashu/threejs-capacitor-ios-game/threejs-builder

نصب در پروژه فعلی:

npx skillhub install chongdashu/threejs-capacitor-ios-game/threejs-builder --project

مسیر پیشنهادی: ~/.claude/skills/threejs-builder/

محتوای SKILL.md

---
name: threejs-builder
description: "Create simple, performant Three.js web apps/scenes (JS/TS, ES modules): scene/camera/renderer setup, lighting, geometries, materials, animation loop, resizing, OrbitControls, GLTF/GLB loading, and practical performance guardrails."
metadata:
  short-description: "Build modern Three.js scenes."
---

# Three.js Builder

A focused skill for creating small, performant Three.js web applications using modern ES module patterns.

## Philosophy: The Scene Graph Mental Model

Three.js is built on the **scene graph**—a hierarchical tree of objects where parent transformations affect children. Understanding this mental model is the fastest path to reliable 3D scenes.

**Before creating a Three.js app, ask**:
- What is the **core visual element**? (geometry, shape, model)
- What **interaction** does the user need? (none, orbit controls, custom input)
- What **performance** constraints exist? (mobile, desktop, WebGL capabilities)
- What **animation** brings it to life? (rotation, movement, transitions)

**Core principles**:

1. **Scene Graph First**: Everything added to `scene` renders. Use `Group` for hierarchical transforms.
2. **Primitives as Building Blocks**: Built-in geometries (Box, Sphere, Torus) cover 80% of simple use cases.
3. **Animation as Transformation**: Change position/rotation/scale over time using `requestAnimationFrame` or `renderer.setAnimationLoop`.
4. **Performance Through Simplicity**: Fewer objects, fewer draw calls, reusable geometries/materials.

---

## Quick Start: Essential Setup

**Prefer npm + bundler in real repos** (Vite/React/etc.): `npm i three` and import from `three` and `three/addons/...`. Use CDN snippets only for truly single-file demos.

### Minimal HTML Template (CDN)

```html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Three.js App</title>
    <style>
        * { margin: 0; padding: 0; box-sizing: border-box; }
        body { overflow: hidden; background: #000; }
        canvas { display: block; }
    </style>
</head>
<body>
    <script type="module">
        import * as THREE from 'https://unpkg.com/[email protected]/build/three.module.js';

        // Scene setup
        const scene = new THREE.Scene();
        const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
        const renderer = new THREE.WebGLRenderer({ antialias: true });

        renderer.setSize(window.innerWidth, window.innerHeight);
        renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
        document.body.appendChild(renderer.domElement);

        // Your 3D content here
        // ...

        camera.position.z = 5;

        // Animation loop
        renderer.setAnimationLoop(() => {
            renderer.render(scene, camera);
        });

        // Handle resize
        window.addEventListener('resize', () => {
            camera.aspect = window.innerWidth / window.innerHeight;
            camera.updateProjectionMatrix();
            renderer.setSize(window.innerWidth, window.innerHeight);
        });
    </script>
</body>
</html>
```

---

## Geometries

Built-in primitives cover most simple app needs. Use `BufferGeometry` only for custom shapes.

**Common primitives**:
- `BoxGeometry(width, height, depth)` - cubes, boxes
- `SphereGeometry(radius, widthSegments, heightSegments)` - balls, planets
- `CylinderGeometry(radiusTop, radiusBottom, height)` - tubes, cylinders
- `TorusGeometry(radius, tube)` - donuts, rings
- `PlaneGeometry(width, height)` - floors, walls, backgrounds
- `ConeGeometry(radius, height)` - spikes, cones
- `IcosahedronGeometry(radius, detail)` - low-poly spheres (detail=0)

**Usage**:
```javascript
const geometry = new THREE.BoxGeometry(1, 1, 1);
const material = new THREE.MeshStandardMaterial({ color: 0x44aa88 });
const mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);
```

---

## Materials

Choose material based on lighting needs and visual style.

**Material selection guide**:
- `MeshBasicMaterial` - No lighting, flat colors. Use for: UI, wireframes, unlit effects
- `MeshStandardMaterial` - PBR lighting. Default for realistic surfaces
- `MeshPhysicalMaterial` - Advanced PBR with clearcoat, transmission. Glass, water
- `MeshNormalMaterial` - Debug, rainbow colors based on normals
- `MeshPhongMaterial` - Legacy, shininess control. Faster than Standard

**Common material properties**:
```javascript
{
    color: 0x44aa88,           // Hex color
    roughness: 0.5,            // 0=glossy, 1=matte (Standard/Physical)
    metalness: 0.0,            // 0=non-metal, 1=metal (Standard/Physical)
    emissive: 0x000000,        // Self-illumination color
    wireframe: false,          // Show edges only
    transparent: false,        // Enable transparency
    opacity: 1.0,              // 0=invisible, 1=opaque (needs transparent:true)
    side: THREE.FrontSide      // FrontSide, BackSide, DoubleSide
}
```

---

## Lighting

No light = black screen (except BasicMaterial/NormalMaterial).

**Light types**:
- `AmbientLight(intensity)` - Base illumination everywhere. Use 0.3-0.5
- `DirectionalLight(color, intensity)` - Sun-like, parallel rays. Cast shadows
- `PointLight(color, intensity, distance)` - Light bulb, emits in all directions
- `SpotLight(color, intensity, angle, penumbra)` - Flashlight, cone of light

**Typical lighting setup**:
```javascript
const ambientLight = new THREE.AmbientLight(0xffffff, 0.4);
scene.add(ambientLight);

const mainLight = new THREE.DirectionalLight(0xffffff, 1);
mainLight.position.set(5, 10, 7);
scene.add(mainLight);

const fillLight = new THREE.DirectionalLight(0x88ccff, 0.5);
fillLight.position.set(-5, 0, -5);
scene.add(fillLight);
```

**Shadows** (advanced, use when needed):
```javascript
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap;

mainLight.castShadow = true;
mainLight.shadow.mapSize.width = 2048;
mainLight.shadow.mapSize.height = 2048;

mesh.castShadow = true;
mesh.receiveShadow = true;
```

---

## Animation

Transform objects over time using the animation loop.

**Animation patterns**:

1. **Continuous rotation**:
```javascript
renderer.setAnimationLoop((time) => {
    mesh.rotation.x = time * 0.001;
    mesh.rotation.y = time * 0.0005;
    renderer.render(scene, camera);
});
```

2. **Wave/bobbing motion**:
```javascript
renderer.setAnimationLoop((time) => {
    mesh.position.y = Math.sin(time * 0.002) * 0.5;
    renderer.render(scene, camera);
});
```

3. **Mouse interaction**:
```javascript
const mouse = new THREE.Vector2();

window.addEventListener('mousemove', (event) => {
    mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
    mouse.y = -(event.clientY / window.innerHeight) * 2 + 1;
});

renderer.setAnimationLoop(() => {
    mesh.rotation.x = mouse.y * 0.5;
    mesh.rotation.y = mouse.x * 0.5;
    renderer.render(scene, camera);
});
```

---

## Camera Controls

Import OrbitControls from examples for interactive camera movement.

**Bundler (npm) import**:
```javascript
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
```

**CDN import**:
```html
<script type="module">
    import * as THREE from 'https://unpkg.com/[email protected]/build/three.module.js';
    import { OrbitControls } from 'https://unpkg.com/[email protected]/examples/jsm/controls/OrbitControls.js';

    // ... scene setup ...

    const controls = new OrbitControls(camera, renderer.domElement);
    controls.enableDamping = true;
    controls.dampingFactor = 0.05;

    renderer.setAnimationLoop(() => {
        controls.update();
        renderer.render(scene, camera);
    });
</script>
```

---

## Common Scene Patterns

### Rotating Cube (Hello World)
```javascript
const geometry = new THREE.BoxGeometry(1, 1, 1);
const material = new THREE.MeshStandardMaterial({ color: 0x00ff88 });
const cube = new THREE.Mesh(geometry, material);
scene.add(cube);

renderer.setAnimationLoop((time) => {
    cube.rotation.x = time * 0.001;
    cube.rotation.y = time * 0.001;
    renderer.render(scene, camera);
});
```

### Floating Particle Field
```javascript
const particleCount = 1000;
const geometry = new THREE.BufferGeometry();
const positions = new Float32Array(particleCount * 3);

for (let i = 0; i < particleCount * 3; i += 3) {
    positions[i] = (Math.random() - 0.5) * 50;
    positions[i + 1] = (Math.random() - 0.5) * 50;
    positions[i + 2] = (Math.random() - 0.5) * 50;
}

geometry.setAttribute('position', new THREE.BufferAttribute(positions, 3));
const material = new THREE.PointsMaterial({ color: 0xffffff, size: 0.1 });
const particles = new THREE.Points(geometry, material);
scene.add(particles);
```

### Animated Background with Foreground Object
```javascript
// Background grid
const gridHelper = new THREE.GridHelper(50, 50, 0x444444, 0x222222);
scene.add(gridHelper);

// Foreground object
const mainGeometry = new THREE.IcosahedronGeometry(1, 0);
const mainMaterial = new THREE.MeshStandardMaterial({
    color: 0xff6600,
    flatShading: true
});
const mainMesh = new THREE.Mesh(mainGeometry, mainMaterial);
scene.add(mainMesh);
```

---

## Colors

Three.js uses hexadecimal color format: `0xRRGGBB`

Common hex colors:
- Black: `0x000000`, White: `0xffffff`
- Red: `0xff0000`, Green: `0x00ff00`, Blue: `0x0000ff`
- Cyan: `0x00ffff`, Magenta: `0xff00ff`, Yellow: `0xffff00`
- Orange: `0xff8800`, Purple: `0x8800ff`, Pink: `0xff0088`

---

## Anti-Patterns to Avoid

### Basic Setup Mistakes

❌ **Not importing OrbitControls from correct path**
Why bad: Controls won't load, `THREE.OrbitControls` is undefined in modern Three.js
Better: Use `import { OrbitControls } from 'three/addons/controls/OrbitControls.js'` or the correct CDN `examples/jsm` path

❌ **Forgetting to add object to scene**
Why bad: Object won't render, silent failure
Better: Always call `scene.add(object)` after creating meshes/lights

❌ **Using old `requestAnimationFrame` pattern instead of `setAnimationLoop`**
Why bad: More verbose, doesn't handle XR/WebXR automatically
Better: `renderer.setAnimationLoop((time) => { ... })`

### Performance Issues

❌ **Creating new geometries in animation loop**
Why bad: Massive memory allocation, frame rate collapse
Better: Create geometry once, reuse it. Transform only position/rotation/scale

❌ **Using too many segments on primitives**
Why bad: Unnecessary vertices, GPU overhead
Better: Default segments are usually fine. `SphereGeometry(1, 32, 16)` not `SphereGeometry(1, 128, 64)`

❌ **Not setting pixelRatio cap**
Why bad: 4K/5K displays run at full resolution, poor performance
Better: `Math.min(window.devicePixelRatio, 2)`

### Code Organization

❌ **Everything in one giant function**
Why bad: Hard to modify, hard to debug
Better: Separate setup into functions: `createScene()`, `createLights()`, `createMeshes()`

❌ **Hardcoding all values**
Why bad: Difficult to tweak and experiment
Better: Define constants at top: `const CONFIG = { color: 0x00ff88, speed: 0.001 }`

---

## Variation Guidance

**IMPORTANT**: Each Three.js app should feel unique and context-appropriate.

**Vary by scenario**:
- **Portfolio/showcase**: Elegant, smooth animations, muted colors
- **Game/interactive**: Bright colors, snappy controls, particle effects
- **Data visualization**: Clean lines, grid helpers, clear labels
- **Background effect**: Subtle, slow movement, dark/gradient backgrounds
- **Product viewer**: Realistic lighting, PBR materials, smooth orbit

**Vary visual elements**:
- **Geometry choice**: Not everything needs to be a cube. Explore spheres, tori, icosahedra
- **Material style**: Mix flat shaded, glossy, metallic, wireframe
- **Color palettes**: Use complementary, analogous, or monochromatic schemes
- **Animation style**: Rotation, oscillation, wave motion, mouse tracking

**Avoid converging on**:
- Default green cube as first example every time
- Same camera angle (front-facing, z=5)
- Identical lighting setup (always directional light at 1,1,1)

---

## Remember

**Three.js is a tool for interactive 3D on the web.**

Effective Three.js apps:
- Start with the scene graph mental model
- Use primitives as building blocks
- Keep animations simple and performant
- Vary visual style based on purpose
- Import from modern ES module paths

**Modern Three.js (r150+) uses ES modules from `three` package or CDN.** CommonJS patterns and global `THREE` variable are legacy.

For advanced topics (GLTF models, shaders, post-processing), see references/advanced-topics.md.

**Codex is capable of creating elegant, performant 3D web experiences. These patterns guide the way—they don't limit the result.**

For game development (state machines, screen effects, animation switching, parallax), see references/game-patterns.md.