files/en-us/web/api/xrview/isfirstpersonobserver/index.md
{{APIRef("WebXR Device API")}}{{SeeCompatTable}}{{SecureContext_Header}}
The {{domxref("XRView")}} interface's read-only isFirstPersonObserver property is a boolean indicating if the XRView is a first-person observer view.
To create video recordings of AR device cameras, you can't simply use one of the rendered eyes, as there often will be a physical offset. Some devices expose a secondary view, the first-person observer view, which has an eye of none.
To receive a first-person observer view, you need to enable the "secondary-views" feature descriptor explicitly (typically as an optional feature). See {{domxref("XRSystem.requestSession()")}} for details.
The isFirstPersonObserver property then allows you to check which secondary view is a first-person observer view.
// Make sure to enable "secondary-view"
navigator.xr
.requestSession("immersive-ar", {
optionalFeatures: ["secondary-views"],
})
.then((session) => {
// …
session.requestAnimationFrame((frame) => {
const views = frame.getViewerPose(space);
// Make sure to iterate over all views
for (const view of views) {
if (view.isFirstPersonObserver) {
renderFPO();
} else {
render();
}
}
});
});
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