XRPose is a WebXR API interface representing a position and orientation in the 3D space, relative to the
XRSpace within which it resides. The
XRSpace—which is either an
XRReferenceSpace or an
XRBoundedReferenceSpace—defines the coordinate system used for the pose and, in the case of an
XRViewerPose, its underlying views.
To obtain the
XRPose for the
XRSpace used as the local coordinate system of an object, call
XRFrame.getPose(), specifying that local
XRSpace and the space to which you wish to convert:
thePose = xrFrame.getPose(localSpace, baseSpace);
The pose for a viewer (or camera) is represented by the
XRViewerPose subclass of
XRPose. This is obtained using
XRFrame.getViewerPose() instead of
getPose(), specifying a reference space which has been adjusted to position and orient the node to provide the desired viewing position and angle:
viewerPose = xrFrame.getViewerPose(adjReferenceSpace);
adjReferenceSpace is a reference space which has been updated using the base frame of reference for the frame and any adjustments needed to position the viewer based on movement or rotation which is being supplied from a source other than the XR device, such as keyboard or mouse inputs.
See the article Movement, orientation, and motion for further details and an example with thorough explanations of what's going on.