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

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 diagram illustrates our virtual log. It is aligned with the 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 a 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...