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

Rendering shadows with shadow maps

One of the most common and popular techniques for producing shadows is called shadow mapping. In its basic form, the algorithm involves two passes. In the first pass, the scene is rendered from the point of view of the light source. The depth information from this pass is saved into a texture called the shadow map. This map will help provide information about the visibility of objects from the light's perspective. In other words, the shadow map stores the distance (actually the pseudo-depth) from the light to whatever the light can see. Anything that is closer to the light than the corresponding depth stored in the map is lit; anything else must be in shadow.

In the second pass, the scene is rendered normally, but each fragment's depth (from the light's perspective) is first tested against the shadow map to determine whether or not the fragment is in shadow. The fragment is then shaded differently depending on the result of this test. If the fragment is...