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

Animating a surface with vertex displacement

A straightforward way to leverage shaders for animation is to simply transform the vertices within the vertex shader based on some time-dependent function. The OpenGL application supplies static geometry, and the vertex shader modifies the geometry using the current time (supplied as a uniform variable). This moves the computation of the vertex position from the CPU to the GPU, and leverages whatever parallelism the graphics driver makes available.

In this example, we'll create a waving surface by transforming the vertices of a tessellated quad based on a sine wave. We'll send down the pipeline a set of triangles that make up a flat surface in the x-z plane. In the vertex shader we'll transform the y-coordinate of each vertex based on a time-dependent sine function, and compute the normal vector of the transformed vertex. The following image shows the desired result. (You'll have to imagine that the waves are travelling across the surface from...