Principles of Digital Image Synthesis

Inspiration begins with imagination and the spirit to create. Then comes the need to communicate, to share an idea or thought. Grab a pencil and you can make it real: a picture, abstraction made concrete, ideas preserved in time. Our hearts and minds are moved to tell stories, to teach what we think and feel to others and learn the same from them.

Of all the visual media, computer graphics is one of the newest. The computer is a powerful amplifier-it can take terse descriptions of the world and create pictures of that world, using any rules you choose. If we choose the classical rules of light, then we can make pictures that can pass for photographs; other rules explore other ways of seeing.

I couldn’t find a book that presented image synthesis as a complete and integrated field of study, encompassing all of the topics I just mentioned. But I love to write. And so this book was born.

The big idea in this book is to lay out the rules that tell a computer how to take 3D shapes and lights and create a picture-one that would pass for a photograph of that scene if it existed. So our driving problem is the simulation of Nature’s illumination of a scene, the capturing of that illumination on film, and its presentation to an observer. Sometimes we bypass the film idea and just imagine an observer in the scene. We often make it easy and pretend the observer has only one eye, so we can ask, ‘Given this scene, what picture do I show to the observer to make her think that she’s viewing the real scene?’ We use all the disciplines I listed earlier to answer this question, since our goal is not merely to create an image, but to create a perceptual response in the viewer.

This book is not about how to write specific programs, or how to implement particular algorithms. The history of computer graphics is like any discipline of thought: tried-and-true ideas are constantly challenged by new ideas, and sometimes the older ones, once seemingly invulnerable, are found somehow deficient and fade away. So it is with rendering algorithms; our marketplace of ideas is a noisy and bustling place right now.

To design and implement a computer system for creating synthetic digital images for people to view, you need to understand the physics of the world you are simulating, the appropriate methods for simulating those physics in the computer, and the nature of the human visual system that ultimately interprets the image.