Preface
The OpenGL Shading Language (GLSL) Version 4.0 brings unprecedented power and flexibility to programmers interested in creating modern, interactive, graphical programs. It allows us to harness the power of modern Graphics Processing Units (GPUs) in a straightforward way by providing a simple, yet powerful, language and API.
The OpenGL 4.0 Shading Language Cookbook will provide easy-to-follow examples that start by walking you through the theory and background behind each technique. It then goes on to provide and explain the GLSL and OpenGL code needed to implement them. Beginning through to advanced techniques are presented, including topics such as texturing, screen-space techniques, lighting, shading, tessellation shaders, geometry shaders, and shadows.
What this book covers
Chapter 1, Getting Started with GLSL 4.0, provides tips and tricks for setting up your OpenGL development environment to take advantage of the latest OpenGL and GLSL language features. It also teaches the basic techniques for communicating with shader programs.
Chapter 2, The Basics of GLSL Shaders, provides examples of basic shading techniques such as diffuse shading, two-sided shading, and flat shading. It also discuses an example of a new 4.0 language feature: subroutines.
Chapter 3, Lighting and Shading Effects and Optimizations, provides examples of more complex lighting and shading such as multiple lights, per-fragment shading, spotlights, cartoon shading, and fog. It moves further to explain how to gain a slight increase in execution speed by using the halfway vector or a directional light source.
Chapter 4, Using Textures, provides a variety of examples illustrating how textures can be used in GLSL shaders. It also explores examples involving simple 2D textures, multiple textures, normal maps, alpha maps, cube maps, and projected textures. It also discusses how to render to a texture using framebuffer objects.
Chapter 5, Image Processing and Screen Space Techniques, discusses various techniques to apply post-processing effects such as bloom, blur, and edge detection. It also discusses an example of a very popular rendering technique known as deferred shading.
Chapter 6, Using Geometry and Tessellation Shaders, provides a series of examples to introduce you to the new and powerful segments of the shader pipeline. It provides some examples of geometry shaders, and discusses how to use tessellation shaders to dynamically render geometry at different levels of detail.
Chapter 7, Shadows, provides several recipes surrounding the shadow-mapping algorithm. It also discusses some basic and advanced techniques for producing shadows, focusing mainly on texture-based shadow maps.
Chapter 8, Using Noise in Shaders, provides recipes that demonstrate how to make use of a pre-computed noise texture to create a variety of effects. The first two recipes demonstrate how to generate a noise texture using the free, open-source library libnoise. Then, it moves on to explain several examples that use noise textures to produce natural and artificial effects such as wood grain, clouds, electrical interference, splattering, and erosion.
Chapter 9, Animation and Particles, discusses several examples of animation within shaders, focusing mostly on particle systems. It also provides an example illustrating how to use OpenGL's transform feedback functionality within a particle system. The last two recipes in the chapter demonstrate some particle systems for simulating complex real systems, such as smoke and fire.
What you need for this book
You will need familiarity with OpenGL programming, along with an understanding of the typical 3D coordinate systems, projections, and transformations.
Who this book is for
This book is for OpenGL programmers who would like to take advantage of the modern features of GLSL 4.0 to create real-time, three-dimensional graphics. It can also be useful for experienced GLSL programmers who are looking to implement the techniques that are presented here.
Conventions
In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.
Code words in text are shown as follows: "The ambient component is computed and stored in the variable named ambient".
A block of code is set as follows:
#version 400
in vec3 LightIntensity;
layout( location = 0 ) out vec4 FragColor;
void main() {
FragColor = vec4(LightIntensity, 1.0);
}When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:
QGLFormat format;
format.setVersion(4,0);
format.setProfile(QGLFormat::CoreProfile);
QGLWidget *myWidget = new QGLWidget(format);New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "The four corners of the quad are given by: e0 – ext, e0 – n – ext, e1 + ext, and e1 –n + ext as shown in the preceding diagram".
Note
Warnings or important notes appear in a box like this.
Tip
Tips and tricks appear like this.
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