Ray Tracing from the Ground Up

Chapter 6

Mapping Samples to a Disk

Objectives

By the end of this chapter you should:

• understand the requirements for a good mapping technique from a square to a disk;
• understand how the concentric map is implemented.

We require sample points distributed on a unit disk for the simulation of depth of field with a circular camera lens in Chapter 10 and for shading with disk lights in Chapter 18. As we can already generate samples on a unit square, it’s natural to generate these as before and then map them to a unit disk. Although a number of techniques can be used for this task, some are better than others.

The basic requirement for a good mapping ...