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

Drawing a wireframe on top of a shaded mesh


The preceding recipe demonstrated the use of a geometry shader to produce a different variety of primitives than it received. Geometry shaders can also be used to provide additional information to later stages. They are quite well-suited to doing so because they have access to all of the vertices of the primitive at once, and can do computations based on the entire primitive rather than a single vertex.

This example involves a geometry shader that does not modify the triangle at all. It essentially passes the primitive along unchanged. However, it computes additional information about the triangle that will be used by the fragment shader to highlight the edges of the polygon. The basic idea here is to draw the edges of each polygon directly on top of the shaded mesh.

The following image shows an example of this technique. The mesh edges are drawn on top of the shaded surface by using information computed within the geometry shader:

There are many...