The OpenGL Shading Language (GLSL) is now a fundamental and critical part of programming with OpenGL. It provides us with unprecedented flexibility and power by making the formerly fixed-function graphics pipeline programmable. With GLSL, we can leverage the Graphics Processing Unit (GPU) to implement advanced and sophisticated rendering techniques and even do arbitrary computation. With GLSL 4.x, programmers can do more with the GPU than ever before thanks to shader stages such as tessellation shaders and compute shaders.

In this book, we cover the full spectrum of GLSL programming. Starting with the basics of shading with the vertex and fragment shaders, we take you from simple to advanced techniques. From textures, shadows, and image processing, to noise and particle systems, we cover practical examples to give you the tools you need to leverage GLSL in your projects. We also cover how to use geometry shaders, tessellation shaders, and the recent addition to GLSL: compute shaders. With these, you can make use of the GPU for a variety of tasks that go beyond just shading. With geometry and tessellation shaders, we can create additional geometry or modify geometry, and with compute shaders we can do arbitrary computation on the GPU.

For those new to GLSL, it's best to read this book in order, starting with Chapter 1, Getting Started with GLSL. The recipes will walk you through from basic through to advanced techniques. For someone who is more experienced with GLSL, you might find it better to pick out specific recipes and jump directly there. Most recipes are self-contained, but some may refer to other recipes. The introduction to each chapter provides important general information about the topic, so you might want to read through that as well.

GLSL 4.x makes programming with OpenGL even more rewarding and fun. I sincerely hope that you find this book to be useful and that you use these recipes as a starting point in your own projects. I hope that you find programming in OpenGL and GLSL as enjoyable as I do, and that these techniques inspire you to create beautiful graphics.