The requestHitTestSource() method of the XRSession interface returns a Promise that resolves with an XRHitTestSource object that can be passed to XRFrame.getHitTestResults().

options

An object containing configuration options, specifically:

space

The XRSpace that will be tracked by the hit test source.

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.

A Promise that resolves with an XRHitTestSource object.

Rather than throwing true exceptions, requestHitTestSource() 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.

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.getHitTestResults() to obtain the result.

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

let hitTestSource = null;

xrSession
  .requestHitTestSource({
    space: viewerSpace, // obtained from xrSession.requestReferenceSpace("viewer");
    offsetRay: new XRRay({ y: 0.5 }),
  })
  .then((viewerHitTestSource) => {
    hitTestSource = viewerHitTestSource;
  });

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

  // do things with the hit test results
}

• XRSession.requestHitTestSourceForTransientInput()