All you see is the color defined for the object as if it were lighted from all directions uniformly. The colors you calculate become the color of the objects in the image module. Do not use an Image module. Throughout this exercise, leave the viewing distance at infinity, that is, leave the Camera module perspective flag at 0. Make an interactor to choose which model you are using.
All surfaces get more shiny at high angle of incidence.
Modify the specular term to simulate this effect. Below is an example of what the modified program might generate. The specular reflection on the vertical plane is releatively diffuse because the angle of incidence is near zero. The light shown is a omnidirectional light. The definition of the reflection vector, R , is given on page 19 of Watt.