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

Screen space ambient occlusion

Ambient occlusion is a rendering technique that is based on the assumption that a surface receives uniform illumination from all directions. Some surface positions will receive less light than others due to objects nearby that occlude some of the light. If a surface point has a lot of local geometry nearby, some of this ambient illumination will be blocked causing the point to be darker.



An example of this is shown in the following image (generated using Blender):  

This image is rendered using ambient occlusion only, without light sources. Note how the result looks like shadows in areas that have local geometry occluding the ambient illumination. The result is quite pleasing to the eye and adds a significant amount of realism to an image.

Ambient occlusion is calculated by testing the visibility of a surface point from the upper hemisphere centered at the surface point. Consider the two points A and B in the following diagram:

Point A is near a corner of the...