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

Structure of a shader's code

The shader's text is a C++ file and contains the void main() function. This function works on GPU and is called once for processing every object (vertex, primitive, or pixel, depending on the shader's type). The main() function has no parameters. All the necessary parameters such as coordinates, colors, and textures are held by built-in GLSL variables such as gl_Color and gl_Position. Also, you can use your own custom parameters passed from your CPU code, such as float time (see the Passing a float parameter to a shader section).

The simplest code for the fragment shader will look as follows:

#version 120
void main() {
  gl_FragColor = vec4( 1.0, 0.0, 0.0, 1.0 );

This shader will render everything in the red color. Namely, if you enable the shader and then draw lines, images, and any other objects, then OpenGL will call the shader's main() function for each drawn pixel, and the shader will set the pixel color to red. Let's study the shader's code in detail.