Let’s continue making our images more realistic; in this chapter, we’ll examine how to add lights to the scene and how to illuminate the objects it contains. First, let’s look at a bit of terminology.
Shading vs. Illumination
The title of this chapter is “Shading,” not “Illumination”; these are two different but closely related concepts. Illumination refers to the math and algorithms necessary to compute the effect of light on a single point in the scene; shading deals with techniques that extend the effect of light on a discrete set of points to entire objects.
In Chapter 3, we looked at all we need to know about illumination. We can ...