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

Point sprites with the geometry shader

Point sprites are simple quads (usually texture mapped) that are aligned such that they are always facing the camera. They are very useful for particle systems in 3D (refer to Chapter 9, Using Noise in Shaders) or 2D games. The point sprites are specified by the OpenGL application as single-point primitives, via the GL_POINTS rendering mode. This simplifies the process, because the quad itself and the texture coordinates for the quad are determined automatically. The OpenGL side of the application can effectively treat them as point primitives, avoiding the need to compute the positions of the quad vertices.

The following image shows a group of point sprites. Each sprite is rendered as a point primitive. The quad and texture coordinates are generated automatically (within the geometry shader) and aligned to face the camera:

OpenGL already has built-in support for point sprites in the GL_POINTS rendering mode. When rendering point primitives using this...