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 noise texture using GLM

To create a texture for use as a source of noise, we need some way to generate noise values. Implementing a proper noise generator from scratch can be a fairly daunting task. Luckily, GLM provides some functions for noise generation that are straightforward and easy to use.

In this recipe, we'll use GLM to generate a 2D texture of noise values created using a Perlin noise generator. GLM can generate 2D, 3D, and 4D Perlin noise via the function glm::perlin.

It is common practice to use Perlin noise by summing the values of the noise function with increasing frequencies and decreasing amplitudes. Each frequency is commonly referred to as an octave (double the frequency). For example, in the following image, we show the results of the 2D Perlin noise function sampled at four different octaves. The sampling frequencies increase from left to right. The leftmost image is the function sampled at our base frequency, and each image to the right shows the function...