Book Image

OpenGL 4 Shading Language Cookbook - Second Edition

By : David Wolff
Book Image

OpenGL 4 Shading Language Cookbook - Second Edition

By: David Wolff

Overview of this book

OpenGL Shading Language (GLSL) is a programming language used for customizing parts of the OpenGL graphics pipeline that were formerly fixed-function, and are executed directly on the GPU. It provides programmers with unprecedented flexibility for implementing effects and optimizations utilizing the power of modern GPUs. With Version 4, the language has been further refined to provide programmers with greater power and flexibility, with new stages such as tessellation and compute. OpenGL 4 Shading Language Cookbook provides easy-to-follow examples that first walk you through the theory and background behind each technique, and then go on to provide and explain the GLSL and OpenGL code needed to implement it. Beginner level through to advanced techniques are presented including topics such as texturing, screen-space techniques, lighting, shading, tessellation shaders, geometry shaders, compute shaders, and shadows. OpenGL Shading Language 4 Cookbook is a practical guide that takes you from the fundamentals of programming with modern GLSL and OpenGL, through to advanced techniques. The recipes build upon each other and take you quickly from novice to advanced level code. You'll see essential lighting and shading techniques; examples that demonstrate how to make use of textures for a wide variety of effects and as part of other techniques; examples of screen-space techniques including HDR rendering, bloom, and blur; shadowing techniques; tessellation, geometry, and compute shaders; how to use noise effectively; and animation with particle systems. OpenGL Shading Language 4 Cookbook 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)
OpenGL 4 Shading Language Cookbook Second Edition
About the Author
About the Reviewers

Creating a fractal texture using the compute shader

We'll wrap up this chapter with an example that makes use of the compute shader to produce an image of a fractal. We'll use the classic Mandelbrot set.

The Mandelbrot set is based on iterations of the following complex polynomial:

Where z and c are a complex numbers. Starting with the value z = 0 + 0i, we apply the iteration repeatedly until a maximum number of iterations is reached or the value of z exceeds a specified maximum. For a given value of c, if the iteration remains stable (z doesn't increase above the maximum) the point is inside the Mandelbrot set and we color the position corresponding to c black. Otherwise, we color the point based on the number of iterations it took for the value to exceed the maximum.

In the following figure, the image of the Mandelbrot set is applied as a texture to a cube:

We'll use the compute shader to evaluate the Mandelbrot set. Since this is another image-based technique, we'll use a two-dimensional...