111 lines
3.0 KiB
Markdown
111 lines
3.0 KiB
Markdown
# Example: Three.js App
|
|
|
|

|
|
|
|
Interactive 3D scene renderer using Three.js. Demonstrates streaming code preview and full MCP App integration.
|
|
|
|
## Features
|
|
|
|
- **Interactive 3D Rendering**: Execute JavaScript code to create and animate Three.js scenes
|
|
- **Streaming Preview**: See the scene build in real-time as code is being written
|
|
- **Built-in Helpers**: Pre-configured `OrbitControls`, post-processing effects (bloom), and render passes
|
|
- **Documentation Tool**: `learn_threejs` provides API docs and code examples on demand
|
|
|
|
## Running
|
|
|
|
1. Install dependencies:
|
|
|
|
```bash
|
|
npm install
|
|
```
|
|
|
|
2. Build and start the server:
|
|
|
|
```bash
|
|
npm run start:http # for Streamable HTTP transport
|
|
# OR
|
|
npm run start:stdio # for stdio transport
|
|
```
|
|
|
|
3. View using the [`basic-host`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-host) example or another MCP Apps-compatible host.
|
|
|
|
### Tool Input
|
|
|
|
To test the example, copy the contents of [`test-input.json`](test-input.json) into the tool input field in `basic-host`.
|
|
|
|
The test input creates a simple scene with a rotating cube:
|
|
|
|
```javascript
|
|
const scene = new THREE.Scene();
|
|
const camera = new THREE.PerspectiveCamera(60, width / height, 0.1, 100);
|
|
camera.position.set(2, 2, 2);
|
|
|
|
const renderer = new THREE.WebGLRenderer({ canvas, antialias: true });
|
|
renderer.setSize(width, height);
|
|
renderer.shadowMap.enabled = true;
|
|
|
|
const cube = new THREE.Mesh(
|
|
new THREE.BoxGeometry(),
|
|
new THREE.MeshStandardMaterial({ color: 0x00ff88 }),
|
|
);
|
|
cube.castShadow = true;
|
|
cube.position.y = 0.5;
|
|
scene.add(cube);
|
|
|
|
const floor = new THREE.Mesh(
|
|
new THREE.PlaneGeometry(5, 5),
|
|
new THREE.MeshStandardMaterial({ color: 0x222233 }),
|
|
);
|
|
floor.rotation.x = -Math.PI / 2;
|
|
floor.receiveShadow = true;
|
|
scene.add(floor);
|
|
|
|
const light = new THREE.DirectionalLight(0xffffff, 2);
|
|
light.position.set(3, 5, 3);
|
|
light.castShadow = true;
|
|
scene.add(light);
|
|
scene.add(new THREE.AmbientLight(0x404040));
|
|
|
|
function animate() {
|
|
requestAnimationFrame(animate);
|
|
cube.rotation.y += 0.01;
|
|
renderer.render(scene, camera);
|
|
}
|
|
animate();
|
|
```
|
|
|
|
#### Available Three.js Globals
|
|
|
|
When writing custom code, these globals are available:
|
|
|
|
```javascript
|
|
THREE; // Three.js library
|
|
canvas; // Pre-created canvas element
|
|
width; // Canvas width
|
|
height; // Canvas height
|
|
OrbitControls; // Camera controls
|
|
EffectComposer; // Post-processing composer
|
|
RenderPass; // Render pass
|
|
UnrealBloomPass; // Bloom effect
|
|
```
|
|
|
|
## Architecture
|
|
|
|
### Server (`server.ts`)
|
|
|
|
Exposes two tools:
|
|
|
|
- `show_threejs_scene` - Renders a 3D scene from JavaScript code
|
|
- `learn_threejs` - Returns documentation and code examples for Three.js APIs
|
|
|
|
Supports Streamable HTTP and stdio transports.
|
|
|
|
### App (`src/threejs-app.tsx`)
|
|
|
|
React component that:
|
|
|
|
- Receives tool inputs via the MCP App SDK
|
|
- Displays streaming preview from `toolInputsPartial.code` as code arrives
|
|
- Executes final code from `toolInputs.code` when complete
|
|
- Renders to a pre-created canvas with configurable height
|