Visualizing tracked motion

Now that we understand how to track motion and have a service in place, let's see how we can put this service to use and visualize the tracked data in our AR app. Open up the spawn-at-surface.html page in a text editor and follow the given steps:

1. Find that last line of code we added in the last exercise and delete it:

firebase.database().ref('pose/' + 1).set({x: 12,y: 1,z : 0});  //delete me

2. Replace that line with the following code:

var idx = 1;
setInterval(function(){
 idx = idx + 1;
 if(camera){
  camera.updateProjectionMatrix();
  var pos = camera.position;
  var rot = camera.rotation;
  firebase.database().ref('pose/' + idx).set({x: pos.x,y: pos.y,z : pos.z, roll: rot._z, pitch: rot._x, yaw: rot._y });
 }  }, 1000);

3. The first line in the preceding snippet is setting an index or count variable. Then, we use the setInterval function to set up a repeating timer that calls the anonymous function every second (1000 milliseconds). We do this so that we only track movement...