Find angle between anchored node and current position of camera in arcore

Question

I want to show, say andy once arcore tracking started and plan is discovered. After I anchored the node somewhere nearby and then i move away from andy.

I have an arrow at the bottom of the screen I want to rotate/point the arrow as i move away my camera such that the arrow always point to the anchored node.

I have done remaining thing but not able to find the angle to which i need to keep rotating the arrow image so that it always point towards anchored node.

I am using sceneform framework, arcore sdk in android studio.

Answer 1

Following is the code I used to achieve what was intended :

 Vector3 cameraPosition = arSceneView.getScene().getCamera().getWorldPosition();
 Vector3 catPosition = catNode.getWorldPosition();
 Vector3 direction = Vector3.subtract(cameraPosition, catPosition);
 Quaternion lookRotation = Quaternion.lookRotation(direction, Vector3.up());
 catNode.setWorldRotation(lookRotation);