# `react-doctor/three-no-material-recompile-in-animation-loop`

Material recompiled inside animation loop

- **Category:** Performance
- **Severity:** error
- **Source:** oxlint-plugin-react-doctor
- **Framework:** global
- **Enabled when:** three

## Validate the diagnostic

Confirm the reported code matches this rule before you edit it.

Confirm the reported code matches `react-doctor/three-no-material-recompile-in-animation-loop`. Compare it with the Before example and verify the same API, framework, and execution context. Treat it as a false positive only when one of those conditions differs.

## Compare the code

The corrected pattern shows a focused way to address the diagnostic.

### Reported pattern

```ts
import { useEffect } from "react";
import { MeshStandardMaterial, WebGLRenderer } from "three";
const material = new MeshStandardMaterial();
const renderer = new WebGLRenderer();
const Scene = () => {
  useEffect(() => {
    renderer.setAnimationLoop(() => {
      material.defines.USE_FOG = fog.enabled;
      material.needsUpdate = true;
      renderer.render(scene, camera);
    });
    return () => renderer.setAnimationLoop(null);
  }, [camera, fog.enabled, scene]);
  return null;
};
```

### Corrected pattern

```ts
import { useEffect } from "react";
import { MeshStandardMaterial, WebGLRenderer } from "three";
const material = new MeshStandardMaterial();
const renderer = new WebGLRenderer();
const Scene = () => {
  useEffect(() => {
    material.defines.USE_FOG = fog.enabled;
    material.needsUpdate = true;
    renderer.setAnimationLoop(() => renderer.render(scene, camera));
    return () => renderer.setAnimationLoop(null);
  }, [camera, fog.enabled, scene]);
  return null;
};
```

## How to fix

Use the corrected pattern as a reference. Preserve behavior that the rule does not require you to change.

### Copyable fix prompt

Copy this self-contained prompt into your coding agent after you confirm the diagnostic.

````text
Fix every confirmed `react-doctor/three-no-material-recompile-in-animation-loop` diagnostic in the current repository.

Required change:
- Change material defines or features outside the animation loop and set needsUpdate only when the compiled program must change.

Reference transformation:

Before:
```ts
import { useEffect } from "react";
import { MeshStandardMaterial, WebGLRenderer } from "three";
const material = new MeshStandardMaterial();
const renderer = new WebGLRenderer();
const Scene = () => {
  useEffect(() => {
    renderer.setAnimationLoop(() => {
      material.defines.USE_FOG = fog.enabled;
      material.needsUpdate = true;
      renderer.render(scene, camera);
    });
    return () => renderer.setAnimationLoop(null);
  }, [camera, fog.enabled, scene]);
  return null;
};
```

After:
```ts
import { useEffect } from "react";
import { MeshStandardMaterial, WebGLRenderer } from "three";
const material = new MeshStandardMaterial();
const renderer = new WebGLRenderer();
const Scene = () => {
  useEffect(() => {
    material.defines.USE_FOG = fog.enabled;
    material.needsUpdate = true;
    renderer.setAnimationLoop(() => renderer.render(scene, camera));
    return () => renderer.setAnimationLoop(null);
  }, [camera, fog.enabled, scene]);
  return null;
};
```

Constraints:
- Confirm the reported code matches the Before pattern.
- Make the smallest change that fixes the root cause.
- Preserve behavior and interfaces unrelated to this diagnostic.
- Reuse existing project components, utilities, and conventions.
- Do not introduce render-phase side effects, render-phase state updates, or Hooks rule violations.
- Preserve resource ownership and cleanup. Do not move work into a hotter render or frame path.
- Adapt identifiers and framework details instead of copying blindly.
- Do not disable the rule or suppress matching code.
- Confirm this rule is enabled for the project: `three`.

Verification:
- Run focused tests for the changed behavior.
- Run React Doctor and confirm this diagnostic no longer appears.
- Report the files changed and any checks you could not run.
````