Realistic Image Synthesis Using Photon Mapping
A practical guide to photon mapping, this book provides both the theory and the insight necessary to implement photon mapping and simulate all types of direct and indirect illumination efficiently.
TABLE OF CONTENTS Realistic Image Synthesis Using Photon Mapping
Chapter 2: Fundamentals of Global Illumination
Understanding the nature of light and how it scatters in the environment is essential to correctly simulate global illumination. After all, global illumination algorithms are trying to mimic the behavior of light in a model. This chapter is divided into three parts: the first part gives an overview of the physical nature of light and the terminology used to describe it. The second part deals with the interaction of light and surfaces and the terminology used. Finally, the third part introduces the rendering equation the fundamental equation that all global illumination algorithms strive to solve.
2.1 The Nature of Light
The nature of light is complicated and still not completely understood. Many theories have been proposed through the ages to describe the physical properties of light. The Greeks around 350 B.C. believed that light was emanating from the eyes and touching the objects that we see. This theory was not seriously attacked until Alhazen (A.D. 956 1038) described how light traveled in straight lines and was reflected by a mirror. He used a camera obscura (a pinhole camera) as a model for the eye. The next two breakthroughs in the understanding of light were reached by Christiaan Huygens (1629 1695) and Isaac Newton (1642 1727). Huygens described how light can be understood as a wave motion and how this could be used to explain the laws of reflection and refraction. Newton demonstrated how white light is made of colored light that can be separated out (and combined again) using a prism. Newton, however, used...
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