Volume Number: 15 (1999)
Issue Number: 9
Column Tag: Reviews

Interactive Computer Graphics

by Doug Whitmore, Santa Cruz, CA

A top-down approach with OpenGL

This article reviews the book Interactive Computer Graphics: A top-down approach with OpenGL by Edward Angel. Interactive Computer Graphics was published by Addison-Wesley in 1997. The publisher indicates that a second edition will be available sometime around September of 1999.

Interactive Computer Graphics is a book for those wanting to learn computer graphics using OpenGL. A discussion of what this book is necessarily starts with a discussion of what this book is not. Unlike OpenGL Programming Guide [Neider 1996](hereafter referred to as the "Red Book"), Interactive Computer Graphics is not a comprehensive guide to programming OpenGL. It is also not a "how to program" book. This book assumes a solid knowledge of C and at least an exposure to basic linear algebra, although it does offer some background math training for those who need a brush up. At the end of the article I will offer some suggestions for supplemental reading for those who need it.

As for what this book is, it is a guide to learning computer graphics, and to teach the concepts, it uses OpenGL as its graphics API. The author believes that to learn graphics programming, you must start out writing programs and continue to do so throughout the entire learning process. Which is why, unlike most textbooks on graphics programming, this one has you writing programs from Chapter 2, all the way through the final chapter. This book also offers end of chapter exercises that are very challenging and interesting. The exercises seem to be designed to force you not only to learn the material, but to enable you to make leaps of understanding. If you complete two or three of the exercises in each chapter, you will have a deep understanding of computer graphics programming by the time you reach chapter 6.

Interactive Computer Graphics is 10 chapters and 3 appendices long. All of the source code for the chapter programs are in Appendix A and are available for download via ftp. The author intended for this book to be a text for a typical semester long computer graphics course for advanced undergraduates or first year graduate students. I believe that it would be useful to those with a good background in programming and basic linear algebra and trigonometry. The book does not assume too much about the math skills of the reader and offers much of the basic skills needed in math.

Getting The Basics

The first chapter of the book is devoted to the obligatory coverage of the history of computer graphics as well as the formation of images on the computer screen. Chapter 2, Graphics Programming, introduces OpenGL and 2D graphics programming. It also begins the discussion of GLUT (OpenGL Utility Toolkit), a platform independent windowing toolkit that is available with any implementation of OpenGL. This chapter also has the distinction of being the first graphics book to so succinctly go through the basics of primitive types, color models, and computer representation of text. A fresh surprise for those of us who were forced to suffer through many chapters of such topics in other books.

Chapter 3, Input and Interaction, is where the book gets the word "interactive" in its title. This chapter is a great introduction to user input and interaction, an important part of modern computer graphics. For those not familiar with event based gui programming, this chapter offers a good introduction. Readers with experience in Mac gui programming will find themselves skimming through large parts of this chapter.

Chapter 4, Geometric Objects and Transformations, will have many readers scrambling for their old linear algebra textbook. Though the chapter offers some math background, those unsure of their math skills would do well to grab a book to bone up on matrix math and trigonometry.

Chapter 5, Viewing, takes readers through the difficult process of learning viewing and perspective transformations. This very difficult subject is presented clearly, with excellent diagrams throughout. It saves the harshness of calculating transforms until the later chapter on implementation. This could be seen as a fault, except that it keeps the reader moving forward in writing programs that implement the viewing models. This defers the detailed understanding until the reader has had a chance to get comfortable with using the viewing models. As a TA for a computer graphics course, this has proved to be much less painful for students, as they understood the viewing transformations well before they were asked to implement them.

Chapter 6, Shading, delves into great detail about light and material interactions. This is different from the other chapters and quite puzzling as many implementation details of the former topics are left to Chapter 7. However, light and shading is a very important part of computer graphics, and it is good to see it given a thorough treatment, even if overly thorough.

The Extras

The final four chapters represent everything beyond the basics. Chapter 7, Implementation, revisits the ugly details that had been glossed over in the earlier chapters. When you have reached this chapter in the book, you have enough to comfortably go your own way and create the next great graphics intensive program. However, if you are one of those that wants to know the hows and whys, chapter 7 will give them to you. From graphics pipeline to clipping and even low level algorithms, it is all in here.

Chapter 8, Working with Models, covers every facet of modeling. With sections on hierarchic, recursive/fractal, physical and parametric modeling, the subject is covered thoroughly, if not as exhaustively as it could have been.

Chapter 9, Curves and Surfaces, gives a person comfortable with their math skills the foundation for interesting modeling techniques. If your math skills are a little rusty, expect to be lost for most of the chapter. On the opposite side, if you are looking for a thorough reference on all curves and surfaces, you will need to look to another book.

Chapter 10, Discrete Techniques, is where everything else that doesn't fit in anywhere else goes. With topics as diverse as texture mapping, anti-aliasing and the other buffers in OpenGL. In "classical" computer graphics, texture mapping isn't given much air time, and the same is true in this book. In today's world, texture mapping is as fundamental to realism as lighting, I would have preferred to see texture mapping handled in one of the earlier chapters. The section on alias effects is the best treatment of the subject that I have seen in any book. It doesn't get caught up in the misguided notion of aliasing as simple "jaggies" on text.

Conclusion

Interactive Computer Graphics: a top-down approach is an excellent book for learning computer graphics programming with OpenGL. The emphasis on programming practice is evident in the examples in the book as well as in the end of chapter assignments that are all very challenging. The first six chapters covering the basics are the ticket you need to start programming non-trivial applications using OpenGL. The final four chapters are a good introduction to some of the more advanced concepts in programming, but tend to lack completeness.

For many people first learning OpenGL, the Red Book is what is recommended to them. However, the Red Book assumes that you already have a certain amount of graphics programming knowledge. Interactive Computer Graphics teaches you that and more. I recommend having both books, as the Red Book is an exhaustive overview of programming with OpenGL, and this book is a great introduction to graphics programming.

Supplemental Books and References

As promised, here is a list of books to act as supplements as well as references.

• Angel, Edward. Interactive Computer Graphics: a top-down approach with OpenGL. Addison-Wesley, 1997.
• Egerton, P. A. and W. S. Hall. Computer Graphics: Mathematical First Steps Prentice Hall 1998. (A great book on basic math for computer graphics for those not feeling confident in their math skills.)
• Foley, James D., Andries van Dam, Steven K. Feiner John F. Hughes and Richard L. Phillips. Computer Graphics, Principles and Practice, Second Edition. Addison-Wesley, 1995. (An encyclopedic reference on computer graphics... the bible of computer graphics.)
• Nieder, Jackie, Tom Davis and Mason Woo. The OpenGL Programming Guide, Second Edition. Addison-Wesley, 1996. (The Red Book.)
• Rogers, David F. and J. Alan Adams. Mathematical Elements for Computer Graphics, Second Edition. McGraw Hill, 1990.

Doug Whitmore (aka Good Doug) is studying for his graduate degree at UC Santa Cruz, where he is currently TA for the Computer Graphics course. He still has no idea of what he wants to be when he grows up, so if you have any ideas, email him at whitmore@cse.ucsc.edu or visit him on the web at http://www.cse.ucsc.edu/~whitmore/