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

Shading with a directional light source


A core component of a shading equation is the vector that points from the surface location toward the light source (s, in previous examples). For lights that are extremely far away, there is very little variation in this vector over the surface of an object. In fact, for very distant light sources, the vector is essentially the same for all points on a surface (another way of thinking about this is that the light rays are nearly parallel). Such a model would be appropriate for a distant, but powerful, light source such as the sun. Such a light source is commonly called a directional light source because it does not have a specific position, only a direction.

 

Note

Of course, we are ignoring the fact that, in reality, the intensity of the light decreases with the square of the distance from the source. However, it is not uncommon to ignore this aspect for directional light sources.

If we are using a directional light source, the direction toward the source...