The book covers all you need to know to write opengl shaders. There are a number of examples covered, with source both in the book and available for download. The writing is understandable and comprehensive, if ponderous.

My only complaint is the encyclopedic nature of the book. Tons of man page like reference material in the back and throughout.

It lacks the inspiration of a book like Frank Luna's DirectX, where he develops techniques like normal mapping, cascaded shadow maps, etc.. with all the relevant math details.



But, if you have those details, this book has everything you need to implement them in GLSL. So a good buy.