three.js/examples/js/vr/HelioWebXRPolyfill.js

if ('xr' in navigator && /(Helio)/g.test(navigator.userAgent)) {

	console.log('Helio WebXR Polyfill', navigator.xr);

	// WebXRManager - XR.supportSession() Polyfill - WebVR.js line 147

	if ('supportsSession' in navigator.xr === false) navigator.xr.supportsSession = navigator.xr.supportsSessionMode;

	if ('requestSession' in navigator.xr) {

		const tempRequestSession = navigator.xr.requestSession.bind(navigator.xr);

		navigator.xr.requestSession = function (sessionType) {

			return new Promise((resolve, reject) => {
				tempRequestSession({
						mode: sessionType
					})
					.then(function (session) {

						// WebXRManager - xrFrame.getPose() Polyfill - line 279

						const tempRequestAnimationFrame = session.requestAnimationFrame.bind(session);

						session.requestAnimationFrame = function (callback) {

							return tempRequestAnimationFrame(function (time, frame) {

								// WebXRManager - xrFrame.getViewerPose() Polyfill - line 279
								// Transforms view.viewMatrix to view.transform.inverse.matrix

								const tempGetViewerPose = frame.getViewerPose.bind(frame);

								frame.getViewerPose = function (referenceSpace) {

									const pose = tempGetViewerPose(referenceSpace);

									pose.views.forEach(function (view) {

										view.transform = {
											inverse: {
												matrix: view.viewMatrix
											}
										}

									})

									return pose;

								}

								// WebXRManager - xrFrame.getPose() Polyfill - line 259

								frame.getPose = function (targetRaySpace, referenceSpace) {

									const inputPose = frame.getInputPose(targetRaySpace, referenceSpace);

									inputPose.transform = {
										matrix: inputPose.targetRay.transformMatrix
									}

									return inputPose;

								}

								callback(time, frame)

							})

						}

						// WebXRManager - xrFrame.getPose( inputSource.targetRaySpace, referenceSpace) Polyfill - line 279

						const tempGetInputSources = session.getInputSources.bind(session);

						session.getInputSources = function () {

							const res = tempGetInputSources();

							res.forEach(xrInputSource => {

								Object.defineProperty(xrInputSource, 'targetRaySpace', {
									get: function () {
										return xrInputSource
									},
								})

							})

							return res;
						}

						// WebXRManager - xrSession.getInputSources() Polyfill Line 132 - 136

						session.inputSources = Object.defineProperty(session, 'inputSources', {
							get: session.getInputSources
						});

						// WebXRManager - xrSession.updateRenderState() Polyfill Line 129

						session.updateRenderState = function ({
							baseLayer
						}) {

							session.baseLayer = baseLayer;

							// WebXRManager - xrSession.renderState.baseLayer Polyfill Line 219

							session.renderState = {
								baseLayer: baseLayer,
							}

						}

						// WebXRManager - xrSession.requestReferenceSpace() Polyfill Line 130

						const temp = session.requestReferenceSpace.bind(session);

						session.requestReferenceSpace = function () {

							return temp({
								type: 'stationary',
								subtype: 'floor-level'
							})

						}

						resolve(session);

					})
					.catch(function (error) {
						return reject(error);
					})
			})

		}

	}

}