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
Contributors
Preface
Index

Using per-fragment shading for improved realism


When the shading equation is evaluated within the vertex shader (as we have done in previous recipes), we end up with a color associated with each vertex. That color is then interpolated across the face, and the fragment shader assigns that interpolated color to the output fragment. As mentioned previously, this technique is called Gouraud shading. Gouraud shading (like all shading techniques) is an approximation, and can lead to some less than desirable results when, for example, the reflection characteristics at the vertices have little resemblance to those in the center of the polygon. For example, a bright specular highlight may reside in the center of a polygon but not at its vertices. Simply evaluating the shading equation at the vertices would prevent the specular highlight from appearing in the rendered result. Other undesirable artifacts, such as edges of polygons, may also appear when Gouraud shading is used, due to the fact that...