XRSession: requestHitTestSourceForTransientInput() method
=========================================================

**Experimental:** **This is an experimental technology**  
Check the Browser compatibility table carefully before using this in production.

 The **`requestHitTestSourceForTransientInput()`** method of the
 `XRSession` interface returns a `Promise` that resolves with an `XRTransientInputHitTestSource` object that can be passed to `XRFrame.getHitTestResultsForTransientInput()`.

Syntax
------


```js
requestHitTestSourceForTransientInput(options)
```

### Parameters

`options`

An object containing configuration options, specifically:

`profile`

A string specifying the input profile name of the transient input source that will be used to compute hit test results.

`entityTypes` Optional

An `Array` specifying the types of entities to be used for hit test source creation. If no entity type is specified, the array defaults to a single element with the `plane` type. Possible types:

* `point`: Compute hit test results based on characteristic points detected.
* `plane`: Compute hit test results based on real-world planes detected.
* `mesh`: Compute hit test results based on meshes detected.

`offsetRay` Optional

The `XRRay` object that will be used to perform hit test. If no `XRRay` object has been provided, a new `XRRay` object is constructed without any parameters.


### Return value

A `Promise` that resolves with an `XRTransientInputHitTestSource` object.

### Exceptions

 Rather than throwing true exceptions, `requestHitTestSourceForTransientInput()` rejects the
 returned promise with a `DOMException`, specifically, one of the following:

`NotSupportedError` `DOMException`

Thrown if `hit-test` is not an enabled feature in `XRSystem.requestSession()`.

`InvalidStateError` `DOMException`

Thrown if the session has already ended.

`NotAllowedError` `DOMException`

Thrown if there is an unreasonable amount of requests. Some user agents might limit usage for privacy reasons.

Examples
--------

### Requesting a transient hit test source

To request a hit test source, start an `XRSession` with the `hit-test` session feature enabled. Next, configure the hit test source and store it for later use in the frame loop and call `XRFrame.getHitTestResultsForTransientInput()` to obtain the result.


```js
const xrSession = navigator.xr.requestSession("immersive-ar", {
  requiredFeatures: ["local", "hit-test"],
});

let transientHitTestSource = null;

xrSession
  .requestHitTestSourceForTransientInput({
    profile: "generic-touchscreen",
    offsetRay: new XRRay(),
  })
  .then((touchScreenHitTestSource) => {
    transientHitTestSource = touchScreenHitTestSource;
  });

// frame loop
function onXRFrame(time, xrFrame) {
  let hitTestResults = xrFrame.getHitTestResultsForTransientInput(
    transientHitTestSource,
  );

  // do things with the transient hit test results
}
```

Specifications
--------------

| Specification |
| --- |
| WebXR Hit Test Module # dom-xrsession-requesthittestsourcefortransientinput |

Browser compatibility
---------------------

BCD tables only load in the browser with JavaScript enabled. Enable JavaScript to view data.

See also
--------

* `XRSession.requestHitTestSource()`