Book Image

OpenGL 4 Shading Language Cookbook - Second Edition

By : David Wolff
Book Image

OpenGL 4 Shading Language Cookbook - Second Edition

By: David Wolff

Overview of this book

OpenGL Shading Language (GLSL) is a programming language used for customizing parts of the OpenGL graphics pipeline that were formerly fixed-function, and are executed directly on the GPU. It provides programmers with unprecedented flexibility for implementing effects and optimizations utilizing the power of modern GPUs. With Version 4, the language has been further refined to provide programmers with greater power and flexibility, with new stages such as tessellation and compute. OpenGL 4 Shading Language Cookbook provides easy-to-follow examples that first walk you through the theory and background behind each technique, and then go on to provide and explain the GLSL and OpenGL code needed to implement it. Beginner level through to advanced techniques are presented including topics such as texturing, screen-space techniques, lighting, shading, tessellation shaders, geometry shaders, compute shaders, and shadows. OpenGL Shading Language 4 Cookbook is a practical guide that takes you from the fundamentals of programming with modern GLSL and OpenGL, through to advanced techniques. The recipes build upon each other and take you quickly from novice to advanced level code. You'll see essential lighting and shading techniques; examples that demonstrate how to make use of textures for a wide variety of effects and as part of other techniques; examples of screen-space techniques including HDR rendering, bloom, and blur; shadowing techniques; tessellation, geometry, and compute shaders; how to use noise effectively; and animation with particle systems. OpenGL Shading Language 4 Cookbook 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)
OpenGL 4 Shading Language Cookbook Second Edition
About the Author
About the Reviewers

Implementing diffuse, per-vertex shading with a single point light source

One of the simplest shading techniques is to assume that the surface exhibits purely diffuse reflection. That is to say that the surface is one that appears to scatter light in all directions equally, regardless of direction. Incoming light strikes the surface and penetrates slightly before being re-radiated in all directions. Of course, the incoming light interacts with the surface before it is scattered, causing some wavelengths to be fully or partially absorbed and others to be scattered. A typical example of a diffuse surface is a surface that has been painted with a matte paint. The surface has a dull look with no shine at all.

The following screenshot shows a torus rendered with diffuse shading:

The mathematical model for diffuse reflection involves two vectors: the direction from the surface point to the light source (s), and the normal vector at the surface point (n). The vectors are represented in the following...