C++

As mentioned in a previous post, openFrameworks is written in the C++ programming language. Even if you are not fluent in C++, there are several resources online for free. If you follow the setup instructions in openframeworks.cc, you'll find that they recommend installing Code::Blocks.

Code::Blocks is a cross-platform IDE (integrated development environment) that supports GCC and MSVC. User friendly, the software is easy to use and allows development for DirectX, OpenGL, and MATLAB on your Windows, Mac, or Linux PC. You may start playing with openFrameworks by following this link and follow this guide to set up your IDE.

As mentioned before, there are several resources online for C++ tutorials.

For those who like to read.
For those who like to watch.