threejs-materials

## When to use this skill

**ALWAYS use this skill when the user mentions:**

- Choosing among built-in mesh materials, map slots (albedo, normal, roughness, metalness, ao, emissive), `envMap`
- Transparency sorting issues, `alphaTest`, `depthWrite`, blending modes, side/double-sided rendering
- `ShaderMaterial` / `RawShaderMaterial` uniforms, includes, and compatibility with lights pipeline
- Line, points, sprite materials for vector overlays and particles

**IMPORTANT: classic materials vs node-tsl**

| Need | Skill |
|------|--------|
| Standard PBR with maps, physical clearcoat/sheen | **threejs-materials** |
| TSL nodes, `NodeMaterial`, WebGPU-first shading, compute-style graph | **threejs-node-tsl** |
| Migrating ShaderMaterial → TSL | **threejs-node-tsl** (conceptual), keep ShaderMaterial here until cutover |

**Trigger phrases include:**

- "MeshStandardMaterial", "MeshPhysicalMaterial", "ShaderMaterial", "transparent", "alphaTest"
- "PBR", "物理材质", "透明", "自定义着色器"

## How to use this skill

1. **Select class** by lighting model: `MeshBasic` (unlit), Lambert/Phong (legacy lit), Standard/Physical (PBR).
2. **Assign maps** and ensure **color space** correctness for albedo vs data maps (link threejs-textures).
3. **Environment**: set `envMap` from cube or equirect; align `metalness`/`roughness`; consider `MeshPhysicalMaterial` for transmission/IOR when needed.
4. **Transparency**: order objects or use `alphaTest`/`depthWrite` trade-offs; mention sorting limitations.
5. **ShaderMaterial**: minimize re-lit work unless intentional; document required lights and `lights: true` flag behavior per version docs.
6. **Performance**: share materials across meshes; avoid cloning per frame.
7. **Skinning/morph**: set `skinning`/`morphTargets` where applicable—mesh side in **threejs-objects**.

### Example: Transparency with alphaTest vs depthWrite

```javascript
// Option A: alphaTest — hard cutoff, no sorting issues
const matA = new THREE.MeshStandardMaterial({
  map: texture, alphaMap: alphaTexture,
  alphaTest: 0.5, transparent: true
});

// Option B: depthWrite false — soft transparency, needs manual sorting
const matB = new THREE.MeshStandardMaterial({
  map: texture, transparent: true, opacity: 0.6,
  depthWrite: false // prevents depth-fighting but requires back-to-front sorting
});
```

See [examples/workflow-pbr-transparent.md](examples/workflow-pbr-transparent.md).

## Doc map (official)

| Docs section | Representative links |
|--------------|----------------------|
| Materials (core) | https://threejs.org/docs/Material.html |
| PBR | https://threejs.org/docs/MeshStandardMaterial.html |
| Physical | https://threejs.org/docs/MeshPhysicalMaterial.html |
| Custom GLSL | https://threejs.org/docs/ShaderMaterial.html |

## Scope

- **In scope:** Non-Node materials listed under Core **Materials** in docs (except `*NodeMaterial`).
- **Out of scope:** Full Nodes catalog (threejs-node-tsl); post pass materials inside composer (threejs-postprocessing).

## Common pitfalls and best practices

- Wrong normal map `normalMapType` or tangent space breaks lighting; verify geometry has tangents or use appropriate mode.
- Premultiplied alpha vs straight alpha mismatches cause fringe halos on foliage.
- `MeshPhysicalMaterial` `transmission` needs thickness and good env—combine with **threejs-textures** / PMREM.
- Too many unique materials hurts sorting and batching—merge where possible.

## Documentation and version

PBR and `ShaderMaterial` behavior track the [Materials](https://threejs.org/docs/#Materials) section in [three.js docs](https://threejs.org/docs/). Color management and default `envMap` handling changed in modern releases—always pair material answers with renderer/output settings from **threejs-renderers** when colors look wrong.

## Agent response checklist

When answering under this skill, prefer responses that:

1. Link `MeshStandardMaterial`, `MeshPhysicalMaterial`, or `ShaderMaterial` pages as appropriate.
2. Force a clear choice vs **threejs-node-tsl** when the user asks for “shaders” or “nodes”.
3. Separate map **roles** (albedo vs roughness vs normal) and `colorSpace` expectations with **threejs-textures**.
4. Call out transparency and `depthWrite` trade-offs for sorted rendering.
5. Note that `*NodeMaterial` types belong to the node skill, not this one.

## References

- https://threejs.org/docs/#Materials
- https://threejs.org/docs/MeshStandardMaterial.html
- https://threejs.org/docs/MeshPhysicalMaterial.html
- https://threejs.org/docs/ShaderMaterial.html

## Keywords

**English:** meshstandardmaterial, meshphysicalmaterial, shadermaterial, pbr, transparency, envmap, materials, three.js

**中文：** 材质、PBR、MeshStandardMaterial、物理材质、透明、环境贴图、ShaderMaterial、three.js