> For the complete documentation index, see [llms.txt](https://docs.multiset.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.multiset.ai/webxr-sdk/api-reference/threeadapter.md).

# ThreeAdapter

```typescript
import { ThreeAdapter } from '@multisetai/vps/three';
```

Integrates `XRSessionManager` with a Three.js scene. Runs the XR render loop, synchronizes the camera each frame, downloads the map mesh on successful localization, and provides a `worldFromMap` matrix for content placement.

### Constructor

```typescript
new ThreeAdapter(options: IThreeAdapterOptions)
```

### Options

| Parameter               | Type                                                                    | Default  | Description                                                                     |
| ----------------------- | ----------------------------------------------------------------------- | -------- | ------------------------------------------------------------------------------- |
| `session`               | `XRSessionManager`                                                      | Required | Session manager                                                                 |
| `renderer`              | `THREE.WebGLRenderer`                                                   | Required | Three.js renderer with `xr.enabled = true`                                      |
| `scene`                 | `THREE.Scene`                                                           | Required | Three.js scene                                                                  |
| `camera`                | `THREE.PerspectiveCamera`                                               | Required | Three.js camera                                                                 |
| `showMesh`              | `boolean`                                                               | `false`  | Download and add the map mesh to the scene after localization                   |
| `showGizmo`             | `boolean`                                                               | `true`   | Show a transform gizmo at the map origin after localization                     |
| `showObjectMeshes`      | `boolean`                                                               | `false`  | Download and display 3D outline meshes for detected objects                     |
| `useDefaultButton`      | `boolean`                                                               | `true`   | Mount the built-in START AR / STOP AR button                                    |
| `buttonContainer`       | `HTMLElement`                                                           | —        | Element to append the button to. Defaults to `overlayRoot` or `document.body`.  |
| `onButtonCreated`       | `(button: HTMLButtonElement) => void`                                   | —        | Called when the button is created                                               |
| `onXRFrame`             | `(event: IXRFrameEvent) => void`                                        | —        | Called every XR frame after camera sync, before rendering                       |
| `onLocalizationSuccess` | `(result: ILocalizeAndMapDetails, worldFromMap: THREE.Matrix4) => void` | —        | Called after successful localization                                            |
| `onObjectMeshLoaded`    | `(objectCode: string) => void`                                          | —        | Called when an object mesh finishes loading. Requires `showObjectMeshes: true`. |

### Static Methods

| Method                       | Returns            | Description                                |
| ---------------------------- | ------------------ | ------------------------------------------ |
| `ThreeAdapter.isSupported()` | `Promise<boolean>` | Check if the browser supports immersive-ar |

### Instance Methods

| Method                         | Returns                                    | Description                                                            |
| ------------------------------ | ------------------------------------------ | ---------------------------------------------------------------------- |
| `initialize(buttonContainer?)` | `HTMLButtonElement \| null`                | Start the preview loop, attach resize handler, and mount the AR button |
| `startSession()`               | `Promise<void>`                            | Start the AR session. Must be called from a user gesture handler.      |
| `stopSession()`                | `void`                                     | Stop the active session                                                |
| `localizeFrame()`              | `Promise<ILocalizeAndMapDetails \| null>`  | Capture and localize one frame                                         |
| `trackObjects()`               | `Promise<IObjectTrackingResponse \| null>` | Capture and run object detection                                       |
| `isActive()`                   | `boolean`                                  | Whether an AR session is running                                       |
| `clearObjectMeshes()`          | `void`                                     | Remove all loaded object meshes from the scene                         |
| `dispose()`                    | `void`                                     | End session, remove listeners, release resources                       |

### Properties

| Property       | Type      | Description                                     |
| -------------- | --------- | ----------------------------------------------- |
| `isLocalizing` | `boolean` | Whether localization or tracking is in progress |

### The `worldFromMap` Matrix

`onLocalizationSuccess` receives a `THREE.Matrix4` that converts map-local coordinates to Three.js world space. Use it to place objects at known positions within the map.

```typescript
onLocalizationSuccess: (result, worldFromMap) => {
  // Place an object at map-local position (x=1, y=0, z=-2)
  const position = new THREE.Vector3(1, 0, -2);
  position.applyMatrix4(worldFromMap);
  myObject.position.copy(position);

  // Or apply the full transform to a group of objects
  const group = new THREE.Group();
  group.applyMatrix4(worldFromMap);
  scene.add(group);
}
```


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