Book Image

GLSL Essentials

By : Jacobo Rodriguez
Book Image

GLSL Essentials

By: Jacobo Rodriguez

Overview of this book

Shader programming has been the largest revolution in graphics programming. OpenGL Shading Language (abbreviated: GLSL or GLslang), is a high-level shading language based on the syntax of the C programming language.With GLSL you can execute code on your GPU (aka graphics card). More sophisticated effects can be achieved with this technique.Therefore, knowing how OpenGL works and how each shader type interacts with each other, as well as how they are integrated into the system, is imperative for graphic programmers. This knowledge is crucial in order to be familiar with the mechanisms for rendering 3D objects. GLSL Essentials is the only book on the market that teaches you about shaders from the very beginning. It shows you how graphics programming has evolved, in order to understand why you need each stage in the Graphics Rendering Pipeline, and how to manage it in a simple but concise way. This book explains how shaders work in a step-by-step manner, with an explanation of how they interact with the application assets at each stage. This book will take you through the graphics pipeline and will describe each section in an interactive and clear way. You will learn how the OpenGL state machine works and all its relevant stages. Vertex shaders, fragment shaders, and geometry shaders will be covered, as well some use cases and an introduction to the math needed for lighting algorithms or transforms. Generic GPU programming (GPGPU) will also be covered. After reading GLSL Essentials you will be ready to generate any rendering effect you need.
Table of Contents (13 chapters)

Chapter 2. GLSL Basics

OpenGL Shading Language is based on ANSI C. Many features of the C programming language have been incorporated to GLSL, while the ones that go against performance or language simplicity have been removed.

All GLSL shader types (vertex, fragment, geometry, and compute) use the same language, so you will benefit a lot from this chapter. All you will learn in this chapter will serve for every following chapter. In this chapter you will learn the basics of the language and the common elements between each shader type. Specifically, we will talk about the following topics:

  • Language basics

  • Shader input/ouput variables

Because GLSL is very close to the C language, I won't expose a complete and exhaustive list of each language element. I'll focus only on the differences between GLSL and C, and the biggest difference of them all, which will definitely lighten up a lot of readers, is that GLSL does not have pointers.