Tidied comments. Reinstated root tracker's position.

plugin/src/main/cpp/extensions/openxr_fb_body_tracking_extension_wrapper.cpp

@@ -307,29 +307,28 @@ void OpenXRFbBodyTrackingExtensionWrapper::_on_process() {
 	// If the location data is good then we need to apply some corrections
 	// before handing the data back to Godot. These include:
 	//
-	// - The Root joint carries no data, so instead place it on the ground
+	// - The Root joint carries no useful orientation data, so instead align it
 	//   under the hips pointing forwards.
 	//
 	// - Adjusting the left and right shoulder back so they are aligned
 	//   with how models are designed, rather than the Meta positions of
 	//   the tips of the clavicles.
 	if (locations.isActive) {
-		// Construct a root under the hips pointing forwards
-		// IE, +z aligns with hips & user's real-world forward.
-		// (Remaining, however, on the XRorigin / Global XZ plane; root's basis rotated around Y to fit)
+		// Align root under the hips pointing 'forwards'
+		// IE, +z aligns with hips & user's real-world [upper-body] forward.
+		// (Remaining, however, parallel to the XRorigin / Global XZ plane; root's basis rotated around Y to fit)
 
 		// Get the hips transform
 		Transform3D hips = xr_body_tracker->get_joint_transform(XRBodyTracker::JOINT_HIPS);
 		Vector3 root_y = Vector3(0.0, 1.0, 0.0);
 		Vector3 hips_left = hips.basis.get_column(Vector3::AXIS_X);
-		// flatten hips' left (x basis) on to real-world / global ground plane. Normalize.
 		Vector3 root_x = (hips_left.slide(Vector3(0.0, 1.0, 0.0))).normalized();
 		Vector3 root_z = root_x.cross(root_y);
-		// flatten hips' origin on to ground plane.
-		Vector3 root_o = hips.origin.slide(Vector3(0.0, 1.0, 0.0));
-		// set the actual root transform
+		Vector3 root_o = xr_body_tracker->get_joint_transform(XRBodyTracker::JOINT_ROOT).origin;
 		Transform3D root = Transform3D(root_x, root_y, root_z, root_o).orthonormalized();
 		xr_body_tracker->set_joint_transform(XRBodyTracker::JOINT_ROOT, root);
+		// Set tracker pose, velocities, confidence.
+		xr_body_tracker->set_pose("default", root, Vector3(), Vector3(), XRPose::XR_TRACKING_CONFIDENCE_HIGH);
 
 		// Distance in meters to push the shoulder joints back from the
 		// clavicle-position to be in-line with the upper arm joints as
@@ -350,9 +349,6 @@ void OpenXRFbBodyTrackingExtensionWrapper::_on_process() {
 		right_shoulder.origin += shoulder_offset;
 		xr_body_tracker->set_joint_transform(XRBodyTracker::JOINT_RIGHT_SHOULDER, right_shoulder);
 
-		// Set tracker pose, velocities, confidence.
-		// Good to go.
-		xr_body_tracker->set_pose("default", root, Vector3(), Vector3(), XRPose::XR_TRACKING_CONFIDENCE_HIGH);
 	}
 
 	// Register the XRBodyTracker if necessary