anchor.diff:  
   [TIP]
   ====
  -“Does that CollisionShape make me look fat? If you ever get confusing physics behaviour, remember to have a look at the collision shapes. Add the following line after the bulletAppState initialization to make the shapes visible:
  +"`Does that CollisionShape make me look fat?`" If you ever get confusing physics behaviour, remember to have a look at the collision shapes. Add the following line after the bulletAppState initialization to make the shapes visible:
   
   [source,java]
   ----
  
positive.code: 
  === 3. setWalkDirection()
  
  Previously in the `onAction()` method, you have collected the info in which direction the user wants to go in terms of “forward or “left. In the update loop, you repeatedly poll the current rotation of the camera. You calculate the actual vectors to which “forward or “left corresponds in the coordinate system.
  
  This last and most important code snippet goes into the `simpleUpdate()` method.
  
  
negative.code: ----
  
  .  You set the background color to light blue, since this is a scene with a sky.
  .  You repurpose the default camera control "`flyCam`" as first-person camera and set its speed.
  .  The auxiliary method `setUpLights()` adds your light sources.
  .  The auxiliary method `setUpKeys()` configures input mappings–we will look at it later.
  
  