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

Parallax mapping

Normal maps are a great way to introduce surface detail without adding additional geometry.  However, they have some limitations. For example, normal maps do not provide parallax effects as the viewer's position changes and they don't support self-occlusion.  Parallax mapping is a technique, originally introduced in 2001, that uses modification of texture coordinates based on a height map to simulate parallax and self-occlusion effects.  It requires both a normal map and a height map.  A height map (also called a bump map) is a grayscale image where each texel has a single scalar value representing the height of the surface at the texel. We can consider any height between 0 and 1 as the true surface, and then use the value in the height map as an offset from there. In this recipe, we'll use a value of 1.0 as the true surface, so a height map value of 0.0 is a distance of 1.0below the true surface (see the following images).

To simulate parallax, we want to offset the texture...