ABSTRACT
This chapter highlights one of the many advantages that ray tracing has over other graphics algorithms. It presents two nonlinear projections: a fisheye projection and a spherical panoramic projection. These both allow us to render the whole scene that surrounds the eye point, a feat that's not possible with perspective or orthographic projections. The chapter provides an understanding of how two types of nonlinear projections are implemented in ray tracing. A fisheye projection uses a view volume that's an infinite circular cone with apex at the eye point and centered on the view direction. A fisheye projection differs from this in two ways. First, only pixels in a circular disk centered on the window have rays associated with them. Second, the field of view is independent of the location and size of the window. A spherical panoramic projection is similar to a fisheye projection, but it has one major difference.
