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
Contributors
Preface
Index

Creating a particle system using transform feedback


Transform feedback provides a way to capture the output of the vertex (or geometry) shader to a buffer for use in subsequent passes. Originally introduced into OpenGL with version 3.0, this feature is particularly well-suited for particle systems, because among other things, it enables us to do discrete simulations. We can update a particle's position within the vertex shader and render that updated position in a subsequent pass (or the same pass). Then the updated positions can be used in the same way as input to the next frame of animation.

In this example, we'll implement the same particle system from the previous recipe (Creating a particle fountain), this time making use of transform feedback. Instead of using an equation that describes the particle's motion for all time, we'll update the particle positions incrementally, solving the equations of motion based on the forces involved at the time each frame is rendered.

A common technique...