Book Image

OpenGL 4.0 Shading Language Cookbook

Book Image

OpenGL 4.0 Shading Language Cookbook

Overview of this book

The 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 4.0, the language has been further refined to provide programmers with greater flexibility, and additional features have been added such as an entirely new stage called the tessellation shader. The OpenGL Shading Language 4.0 Cookbook provides easy-to-follow examples that first walk you through the theory and background behind each technique then go on to provide and explain the GLSL and OpenGL code needed to implement it. Beginning level through to advanced techniques are presented including topics such as texturing, screen-space techniques, lighting, shading, tessellation shaders, geometry shaders, and shadows. The OpenGL Shading Language 4.0 Cookbook is a practical guide that takes you from the basics of programming with GLSL 4.0 and OpenGL 4.0, through basic lighting and shading techniques, to more advanced techniques and effects. It presents techniques for producing basic lighting and shading effects; 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, shadowing, tessellation and geometry shaders, noise, and animation. The OpenGL Shading Language 4.0 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 (16 chapters)
OpenGL 4.0 Shading Language Cookbook
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Simulating fire with particles


To create an effect that roughly simulates fire, we only need to make a few changes to our basic particle system. Since fire is a substance that is only slightly affected by gravity, we don't worry about a downward gravitational acceleration. In fact, we'll actually use a slight upwards acceleration to make the particles spread out near the top of the flame. We'll also spread out the initial positions of the particles so that the base of the flame is not just a single point. Of course, we'll need to use a particle texture that has the red and orange colors associated with flame.

The following image shows an example of the running particle system:

The texture that was used for the particles looks like a light "smudge" of the flame's colors. It is not shown here because it would not be very visible in print.

Getting ready

Start with the basic particle system presented in the recipe Creating a particle system using transform feedback.

Set the uniform variable Accel...