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

Simulating refraction with cube maps


Objects that are transparent cause the light rays that pass through them to bend slightly at the interface between the object and the surrounding environment. This effect is called refraction. When rendering transparent objects, we simulate that effect by using an environment map and mapping the environment onto the object is such a way as to mimic the way that light would pass through the object. In other words, we can trace the rays from the viewer, through the object (bending in the process), and along to the environment. Then, we can use that ray intersection as the color for the object.

As in the previous recipe, we'll do this using a cube map for the environment. We'll trace rays from the viewer position, through the object, and finally intersect with the cube map.

The process of refraction is described by Snell's law, which defines the relationship between the angle of incidence and the angle of refraction:

Snell's law describes the angle of incidence...