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
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Creating a wood-grain effect


To create the look of wood, we can start by creating a virtual "log", with perfectly cylindrical growth rings. Then we'll take a slice of the log, and perturb the growth rings using noise from our noise texture.

The following image illustrates our virtual "log". It is aligned with the y-axis, and extends infinitely in all directions. The growth rings are aligned with integer distances from the y-axis. Each ring is given a darker color with lighter color in between rings. Each growth ring spans a narrow distance around the integer distances.

To take a "slice", we'll simply define a 2D region of the log's space based on the texture coordinates. Initially, the texture coordinates define a square region, with coordinates ranging from zero to one. We'll assume that the region is aligned with the x-y plane, so that the s coordinate corresponds to x, the t coordinate corresponds to y, and the value of z is zero. We can then transform this region in any way that suits...