Ray Tracing from the Ground Up

Chapter 17

Ambient Occlusion

Image courtesy of Mark Howard, Stanford bunny model courtesy of Greg Turk and the Stanford University Graphics Laboratory

Objectives

By the end of this chapter, you should:

• understand how ambient occlusion is computed;
• know how to set up a local orthonormal basis at a hit point;
• have implemented ambient occlusion as a light shader;
• understand some of the limitations of the sampling techniques discussed in Chapter 5.

In Chapter 14, ambient illumination was a constant term throughout a scene. As a result, the surface of any object that only received ambient illumination was rendered with a constant color. Ambient ...