> For the complete documentation index, see [llms.txt](https://multiset.gitbook.io/multiset/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://multiset.gitbook.io/multiset/web-sdk/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. The adapter manages `renderer.xr` itself, so you do not need to enable it. | | `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` | 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` | Start the AR session. Must be called from a user gesture handler. | | `stopSession()` | `void` | Stop the active session | | `localizeFrame()` | `Promise` | Capture and localize one frame | | `trackObjects()` | `Promise` | 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 | ### Events and Scene Access The `onLocalizationSuccess` and `onXRFrame` options are single-slot: setting one replaces it. Use the listeners below when more than one part of your app needs to react. Anything layered on the adapter, including [MapSpace](/multiset/web-sdk/webxr-sdk/api-reference/mapspace.md) and [Navigation](/multiset/web-sdk/webxr-sdk/features/navigation.md), uses them, so they compose. Every `add*Listener` **returns its own unsubscribe function**, which is usually easier than keeping a reference for the matching `remove*Listener`. | Method | Returns | Description | | -------------------------------- | --------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------- | | `addLocalizationListener(fn)` | `() => void` | `fn(result, worldFromMap)` after every successful localization | | `removeLocalizationListener(fn)` | `void` | Unsubscribe. Equivalent to calling the returned function. | | `addSessionStartListener(fn)` | `() => void` | Fires when the AR session starts | | `removeSessionStartListener(fn)` | `void` | Unsubscribe | | `addSessionEndListener(fn)` | `() => void` | Fires when the AR session ends | | `removeSessionEndListener(fn)` | `void` | Unsubscribe | | `addFrameListener(fn)` | `() => void` | `fn(event)` every XR frame, after camera matrices are synced and before the scene renders, so anything you move lands in the same frame | | `removeFrameListener(fn)` | `void` | Unsubscribe | | `waitForLocalization()` | `Promise` | Resolves immediately if the current session has already localized, otherwise on the next success. Never rejects. | | `getLastLocalization()` | `ILocalizationSnapshot \| null` | The current session's most recent result and its `worldFromMap`. Cleared when the session ends, so a stale pose can never be replayed into a new session. | | `getScene()` | `THREE.Scene` | The active scene | | `getCamera()` | `THREE.Camera` | The XR-driven camera | `waitForLocalization()` replaces the usual "do this once we are localized" callback plumbing: ```typescript await adapter.waitForLocalization(); // the map frame is positioned; safe to read poses or start navigation ``` {% hint style="warning" %} Read the camera pose with `camera.getWorldPosition(target)` or `camera.matrixWorld`, never `camera.position`. During a session the adapter writes `matrixWorld` directly and leaves `position` and `quaternion` untouched, so reading `position` returns a stale value. {% endhint %} ### IVpsAdapter Both adapters satisfy the same `IVpsAdapter` contract, so a feature written against it works on either one and on any future adapter. ```typescript import type { IVpsAdapter } from '@multisetai/vps/three'; function attachMyFeature(adapter: IVpsAdapter) { return adapter.addLocalizationListener((result, worldFromMap) => { // ... }); } ``` They satisfy it **structurally**, so neither declares `implements`. A compile-time guard in each entry point fails the build if one drifts from the interface. `ILocalizationSnapshot` is `{ result: ILocalizeAndMapDetails; worldFromMap: THREE.Matrix4 }`. ### 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); } ``` --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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