DirectX 2002: Vertex and Pixel Shaders (Wordware Game Developer's Library) [Illustrated] [Paperback]

ShaderX2 is broken in to two volumes, with this volume intended as an introduction to shader related topics to prepare the reader for the other volume, or for other shader books. It fills that role fairly well, though it does have a few shortcomings that keep it from being a great book.

The book starts off with an extensive, well-written introduction to HLSL that most beginners to the language will find quite helpful. This is followed by a handy introduction to Shader Model 3.0, which explains the changes that have been made since 2.0, and the practical applications of these changes and additions.

The next several chapters are devoted to implementing "foundational" techniques using shaders. The first covers several lighting and shading techniques, providing sample shader implementations in HLSL and assembly. Most of the shaders come in multiple versions for the various shader models, which is useful for supporting these techniques on a wide range of platforms, as well as in understanding the capability differences between each model.

The next chapter covers five different fog effects using HLSL shaders. Then there are two chapters on shadows, one on shadow mapping and the other on shadow volumes. The latter weighs in at over 80 pages, providing in-depth coverage of the theory behind the technique.

Next up is a tutorial for using the shader development environment RenderMonkey. The usefulness of this chapter is marred by the fact that the current version of RenderMonkey has undergone some interface changes such that the text is now out of synch with the tool, making it a bit more difficult to follow along. Still, if you can work through this, the chapter will help you quickly get up and running with RenderMonkey.

The last chapter of the book is about creating shader-friendly models. This chapter seems out of place since it's written more for artists than programmers (who are clearly the audience for the rest of the book), and the chapter is too brief and vague to be of much value.

If you're new to shaders and HLSL, you'll likely find this book useful, though it's a little expensive for a small book (I imagine the color plates contribute to this). If the shadow and fog chapters had been moved to the other ShaderX2 book, and the final chapter had been dropped, I think that they could have reduced the price considerably and made the book more focused, turning it into a great value. As it is, though, it's still a good book that many people will benefit from.

So let's focus on the good.

First, it gives a fair intro to HLSL and shader assembly language. That seems hard to come by. Microsoft's documentation, in web-entangled form, is hardly a tutorial. Vendor documentation mostly points to MS standards, but those are hard for us mere peons to acquire in any intelligible form. This isn't a langauge ref book, but will do until I see a real one.

Second, it gives a good bunch of tips'n'tricks, with lots of listings for illumination models, shadows, and fog. The careful reader will look into the references, the places where new knowledge makes its debut, and will be stronger for it. There's also a chapter that devotes itself to v1 vs. v2. vs v3 compatibility and more. Compatibility is the pits - if you've never dealt with it, your career is probably happy and probably very young.

I was looking for something a little different, though. I just wanted the HLSL and assembly references, with versions, with complete syntax and semantics. This gives enough info for me to guess my way through a lot of it, but really does leave me guessing. For example, p.47 talks about the "_bx2" modifier. It shows three different ways to coax the compiler into emitting that suffix. After about ten minutes of looking at source and asm code, I finally figured out what _bx2 meant - something the authors neglected to tell me.

Shader programming is still a [forgive the phrase] dark art. This book offers a few chants and incantations, but does not make it a science. Still, it's the most coherent reference I've seen, and I'm sticking with it.

If you know nothing about the High-Level Shader Language (HLSL), then the information you need is in this book. Unfortunately, it's not a particularly well-written book. It's not horrible either, but it could have used better organization and clearer writing. For example, the "Introduction to the DirectX HLSL" chapter never gives an overall picture of how vertex and pixel shaders interact, and how data flows between them and the hardware. The author jumps right into to discussing shader syntax. Then, when he's barely explained enough to see what's going on, he jumps into a section on optimization, then a section on compatibility details between various shader levels, then he abruptly starts talking about code sequences that generate "_bx2" modifiers, without any set-up or real explanation of why. I realize that each chapter is written by a different person, but all of this random gear-shifting is in the same chapter.

As in any book with many contributors, the quality varies. The chapter on shadow volumes is detailed and useful. But overall I wish there had been emphasis on clear and succinct presentation, and not just what seems to be a stream-of-consciousness approach to covering a huge amount of information.