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)

Execution model


In the case of different shader types, the Rendering Pipeline decided how and when they had to be invoked. Since the Rendering Pipeline stopped working, we had to take care of its jobs—synchronization, thread management, and so on.

Anticipate a single computer shader execution. Computer shaders' terminology defines this as a work item. These work items cannot be invoked independently; they are separated in groups. A work group encapsulates an arbitrary number of work items, which is specified by the programmer but limited by the hardware capabilities. Work groups run all their items in a parallel way—more or less synchronized. Also, items inside a group can share memory and synchronization mechanisms. All work groups must have the same number of work items and each work group is executed independently from the others, totally isolated, and in an unspecified order.

Furthermore, work groups are grouped by dimensions. We can choose to arrange them in one, two, or three dimensions...