Book Image

OpenGL 4 Shading Language Cookbook - Third Edition

By : David Wolff
Book Image

OpenGL 4 Shading Language Cookbook - Third Edition

By: David Wolff

Overview of this book

OpenGL 4 Shading Language Cookbook, Third Edition provides easy-to-follow recipes that first walk you through the theory and background behind each technique, and then proceed to showcase and explain the GLSL and OpenGL code needed to implement them. The book begins by familiarizing you with beginner-level topics such as compiling and linking shader programs, saving and loading shader binaries (including SPIR-V), and using an OpenGL function loader library. We then proceed to cover basic lighting and shading effects. After that, you'll learn to use textures, produce shadows, and use geometry and tessellation shaders. Topics such as particle systems, screen-space ambient occlusion, deferred rendering, depth-based tessellation, and physically based rendering will help you tackle advanced topics. OpenGL 4 Shading Language Cookbook, Third Edition also covers advanced topics such as shadow techniques (including the two of the most common techniques: shadow maps and shadow volumes). You will learn how to use noise in shaders and how to use compute shaders. The book provides examples of modern shading techniques that can be used as a starting point for programmers to expand upon to produce modern, interactive, 3D computer-graphics applications.
Table of Contents (17 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Sending data to a shader using uniform variables


Vertex attributes offer one avenue for providing input to shaders; a second technique is uniform variables. Uniform variables are intended to be used for data that may change relatively infrequently compared to per-vertex attributes. In fact, it is simply not possible to set per-vertex attributes with uniform variables. For example, uniform variables are well-suited to the matrices used for modeling, viewing, and projective transformations.

Within a shader, uniform variables are read-only. Their values can only be changed from outside the shader, via the OpenGL API. However, they can be initialized within the shader by assigning them to a constant value along with the declaration.

Uniform variables can appear in any shader within a shader program, and are always used as input variables. They can be declared in one or more shaders within a program, but if a variable with a given name is declared in more than one shader, its type must be the same...