4.7. Further Information
The built-in variables defined in this chapter are used in various examples throughout this book. The OpenGL Shading Language specification and the OpenGL specification can be consulted for additional details. The OpenGL books referenced at the conclusion of Chapter 1 can also be consulted for a better understanding of the OpenGL state that is referenced through built-in variables. Parts of the paper Integrating the OpenGL Shading Language by Barthold Lichtenbelt have been adapted for inclusion in this book.