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

Applying an edge detection filter


Edge detection is an image processing technique that identifies regions where there is a significant change in the brightness of the image. It provides a way to detect the boundaries of objects and changes in the topology of the surface. It has applications in the field of computer vision, image processing, image analysis, and image pattern recognition. It can also be used to create some visually interesting effects. For example, it can make a 3D scene look similar to a 2D pencil sketch, as shown in the following image. To create this image, a teapot and torus were rendered normally, and then an edge detection filter was applied in a second pass:

The edge detection filter that we'll use here involves the use of a convolution filter, or convolution kernel (also called a filter kernel). A convolution filter is a matrix that defines how to transform a pixel by replacing it with the sum of the products between the values of nearby pixels and a set of pre-determined...