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

Simulating a spotlight


The fixed function pipeline had the ability to define light sources as spotlights. In such a configuration, the light source was considered to be one that only radiated light within a cone, the apex of which was located at the light source. Additionally, the light was attenuated so that it was maximal along the axis of the cone and decreased toward the outside edges. This allowed us to create light sources that had a similar visual effect to a real spotlight.

The following screenshot shows a teapot and a torus rendered with a single spotlight. Note the slight decrease in the intensity of the spotlight from the center toward the outside edge:

In this recipe, we'll use a shader to implement a spotlight effect, similar to that produced by the fixed-function pipeline:

The spotlight's cone is defined by a spotlight direction (d, in the preceding image), a cutoff angle (c, in the preceding image), and a position (P, in the preceding image). The intensity of the spotlight is...