openFrameworks, "libraries," and openGL calls

Can anyone help me decipher this post made by a Ridiculous Fishing developer ? I want to make my own sequel just for personal use. He says:

It was made with openFrameworks and a custom library for spritesheet rendering. I think the biggest tool I have is a very tiny library I wrote about 2 years ago with some help from my friend Ramsey Nasser. It’s opensource here: ( although the docs aren’t great. I use OpenFrameworks for all of the ease of getting setup in xcode and some of the event structure, but all of my openGL calls go through that custom library. It handles spritesheets (and on the fly created sprite sheets), rotation, batching, layers, antialiased shape and line drawing, etc. It’s how we managed to have RF run so well even on super old devices.

I now know what Xcode is since the 7-day program has explained it, but is openFraneworks a different version of Swift ? I want to use the same exact tools this developer used.

Thanks in advance !