Book Image

Mastering openFrameworks: Creative Coding Demystified

By : Denis Perevalov
Book Image

Mastering openFrameworks: Creative Coding Demystified

By: Denis Perevalov

Overview of this book

openFrameworks is a powerful programming toolkit and library designed to assist the creative process through simplicity and intuitiveness. It's a very handy software library written in C++ to reduce the software development process, helping you to kick-start creative coding. With the help of C++ and shaders support, openFrameworks allows for the processing of all kinds of media information with your custom-developed algorithms at the lowest possible level, with the fastest speed. "Mastering openFrameworks: Creative Coding Demystified" will introduce you to a world of creative coding projects, including interactive installations, audio-visual, and sound art projects. You will learn how to make your own projects using openFrameworks. This book focuses on low-level data processing, which allows you to create really unique and cutting-edge installations and projects. "Mastering openFrameworks: Creative Coding Demystified" provides a complete introduction to openFrameworks, including installation, core capabilities, and addons. Advanced topics like shaders, computer vision, and depth cameras are also covered. We start off by discussing the basic topics such as image and video loading, rendering and processing, playing sound samples, and synthesizing new sounds. We then move on to cover 3D graphics, computer vision, and depth cameras. You will also learn a number of advanced topics such as video mapping, interactive floors and walls, video morphing, networking, and using geometry shaders. You will learn everything you need to know in order to create your own projects; create projects of all levels, ranging from simple creative-code experiments, to big interactive systems consisting of a number of computers, depth cameras, and projectors.
Table of Contents (22 chapters)
Mastering openFrameworks: Creative Coding Demystified
About the Author
About the Reviewers

Creating video effects with fragment shaders

In this section, we will extend the knowledge of shaders and will see how to pass parameters from your C++ code, how to use Perlin noise, and how to process several images. The examples will be about the fragment shaders, but all the principles extend to the vertex and geometry shaders.

Passing a float parameter to a shader

In order to make the shader interactive, we need a way to pass in it some parameters, such as time, mouse position, and some arrays. To add a parameter, you need to add its declaration in the shader's code using the uniform keyword. For example, to declare the time parameter, use the following line:

uniform float time;

To specify the parameter's value in openFrameworks, you need to add the following line after the shader.enable() calling:

shader.setUniform1f( "time", time );

The 1f suffix in the setUniform1f() function name means that you pass one float value to the shader. The first parameter "time" indicates the parameter name...