Book Image

OpenGL 4 Shading Language Cookbook - Third Edition

By : David Wolff
Book Image

OpenGL 4 Shading Language Cookbook - Third Edition

By: David Wolff

Overview of this book

OpenGL 4 Shading Language Cookbook, Third Edition provides easy-to-follow recipes that first walk you through the theory and background behind each technique, and then proceed to showcase and explain the GLSL and OpenGL code needed to implement them. The book begins by familiarizing you with beginner-level topics such as compiling and linking shader programs, saving and loading shader binaries (including SPIR-V), and using an OpenGL function loader library. We then proceed to cover basic lighting and shading effects. After that, you'll learn to use textures, produce shadows, and use geometry and tessellation shaders. Topics such as particle systems, screen-space ambient occlusion, deferred rendering, depth-based tessellation, and physically based rendering will help you tackle advanced topics. OpenGL 4 Shading Language Cookbook, Third Edition also covers advanced topics such as shadow techniques (including the two of the most common techniques: shadow maps and shadow volumes). You will learn how to use noise in shaders and how to use compute shaders. The book 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)
Title Page
Packt Upsell

Simulating smoke with particles

Smoke is characterized by many small particles that float away from the source, and spread out as they move through the air. We can simulate the floatation effect with particles by using a small upwards acceleration (or constant velocity), but simulating the diffusion of each small smoke particle might be too expensive. Instead, we can simulate the diffusion of many small particles by making our simulated particles change their size (grow) over time.

The following image shows an example of the results:

The texture for each particle is a very light smudge of grey or black color.

To make the particles grow over time, we'll simply increase the size of our quads.

Getting ready

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

  1. Set the uniform variable Accel to a small upward value like (0.0, 0.1, 0.0).
  2. Set the ParticleLifetimeuniform variable to about 10 seconds.
  3. Create and load a texture for the particles...