In this chapter you will get acquainted with openFrameworks, learn its specifics and cases when you should use it. Also you will study how to install openFrameworks, run its examples, and make your first openFrameworks project:
- Installing openFrameworks and running your first example
- File structure of a project
- Code structure of a project
- Creating a first project – the Pendulum example
- Running the book's examples
openFrameworks is an open source C++ toolkit for creative coding. It was initially released by Zachary Lieberman in 2005. Today openFrameworks is one of the main creative coding platforms, which is actively developed by Zachary Lieberman, Theodore Watson, and Arturo Castro with help from the openFrameworks community.
The toolkit is indebted to two significant precursors: the Processing development environment, created by Casey Reas, Ben Fry, and the Processing community; and the ACU Toolkit, a privately distributed C++ library developed by Ben Fry and others in the MIT Media Lab's Aesthetics and Computation Group.
openFrameworks' website is http://openframeworks.cc. It contains latest downloads, documentation, tutorials, and forums.
The main purpose of openFrameworks is to provide users with an easy access to multimedia, computer vision, networking, and other capabilities in C++ by gluing many open libraries into one package. Namely, it acts as a wrapper for libraries such as OpenGL, FreeImage, and OpenCV. The term wrapper means that openFrameworks provides you with new functions and classes, and gives hints on a project structure, but does not limit you. Namely, you can still use all of the C++ capabilities, and directly call functions from all of the linked libraries without using the wrapper's classes.
openFrameworks is cross-platform compatible with Windows, Mac OS X, Linux, iOS, and Android as the supported platforms. It means that if you develop a project for one of the platforms, you can copy the source files and compile the project for any other platform from the list. In the book we will cover developing a project for Windows, Mac OS X, and Linux only. Though many of the examples considered will work on mobile platforms too.
There are many great projects made with openFrameworks. Here are a few "classical" ones:
- Funky Forest by Emily Gobeille and Theodore Watson, 2007 – the interactive forest installation
- Body Paint by Mehmet Akten, 2009 – drawing on the wall by moving the user's body
- Hand from Above by Chris O'Shea, 2009 – outdoor installation working on a big billboard and interacting with pedestrians
openFrameworks has the following architectural specifics:
- Its core is based around multimedia, including 2D and 3D graphics, images, video, and sound. So openFrameworks is especially appropriate for developing multimedia projects working in real-time environments.
- It works using C++ language, which implies that the code is compiled into native machine instructions and hence works very fast. So it lets you create computing-intensive, ground-breaking projects, using the top capabilities of modern computing technologies.
Such specifics determine cases when you should and should not use openFrameworks for a project development.
You definitely can employ openFrameworks when:
- You need to make a creative coding project, such as an interactive audio-visual installation or performance, which works with multimedia in a nontrivial and custom way. Namely, such a project would render a custom particle system, apply effects such as video morphing and slit-scan, or even perform data transcoding.
- You need to create a project, which performs intensive data analysis, for example, analyzing data from depth cameras.
Maybe you should not use openFrameworks when:
- The project is centered on working with visual controls such as buttons, checkboxes, lists, and sliders. In this case the better option is in using developing platforms like QT, Cocoa, or .Net.
- The project does not use multimedia or intensive computations a lot. For example, if you just want to send simple commands to a robot, it is definitely simpler to use Processing.
Tip
Though openFrameworks is an open source project, currently you can use it for developing commercial projects (see details in the openFrameworks license at http://www.openframeworks.cc/about/license.html). To protect the project's content, to add licensing, and to create an installer, you should use special additional software. Note that all of this software is included in iOS and Android development kits, so commercial developing for mobile platforms is quite easy.