Camera Ray Perturbation

### 6.4.4 Camera Ray Perturbation

The optional `normal` may be used to assign a normal pattern to the camera. For example:

     camera{
       location Here
       look_at There
       normal { bumps 0.5 }
     }

All camera rays will be perturbed using this pattern. The image will be distorted as though you were looking through bumpy glass or seeing a reflection off of a bumpy surface. This lets you create special effects. See the animated scene `camera2.pov` for an example. See "Normal" for information on normal patterns.