3-run-render-loop-xr-session.js

//L135-146,onSessionStarted内
session.requestReferenceSpace('viewer').then((refSpace) => {
  xrViewerSpace = refSpace;
  session.requestHitTestSource({ space: xrViewerSpace }).then((hitTestSource) => {
    xrHitTestSource = hitTestSource; //hit testの要求
  });
});
session.requestReferenceSpace('local').then((refSpace) => {
  xrRefSpace = refSpace;
  session.requestAnimationFrame(onXRFrame); //Render loop処理のコール
});