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 particle system using instanced particles

To give more geometric detail to each particle in a particle system, we can make use of OpenGL's support for instanced rendering. Instanced rendering is a convenient and efficient way to draw several copies of a particular object. OpenGL provides support for instanced rendering through the functions glDrawArraysInstanced and glDrawElementsInstanced.

In this example, we'll modify the particle system introduced in the previous recipes. Rather than using point sprites, we'll render a more complex object in the place of each particle. The following image shows an example where each particle is rendered as a shaded torus.

Using instanced rendering is simply a matter of calling one of the instanced draw functions, providing the number of instances to draw. However, there is some subtlety to the way that we provide vertex attributes to the shader. If all particles were drawn with exactly the same attributes, it would be simple to draw, but would...