Can I use OpenFrameworks on OS X without having to use XCode?

Xcode internally uses gcc/llvm. in fact from the command line you can cd into a directory that contains an openFrameworks project and just type xcodebuild. but this won't allow you to edit the project file and add new source code, etc.

the Linux makefiles could be adapted to work on OSX as well. they already contain a lot of the information necessary about finding the correct source files, library paths etc. however Linux allows us to install many more components as shared system libraries, while on OSX we link most of the libs statically, so a number of extra library paths would need to be added. probably the biggest gotcha is that everything has to be compiled 32 bit, which means passing -arch i386 everywhere, so you can't just install dependant libs using Homebrew or MacPorts. we are in the process of transitioning to 64 bit but there are still some QuickTime calls that require us to stick with 32 bit, mainly around accessing legacy video capture devices that a lot of us still use for computer vision.

like @cdelacroix points out, we only maintain Xcode project files on OSX. this is mainly due to the lack of a decent alternative. there is a version of Code::Blocks for OSX but it is not very well supported, has some issues with native gui rendering and tends to lag behind the other platforms. Xcode is also the easiest way to install a toolchain on OSX so for most users installing Xcode is necessary.

if you do get a makefile based build system working, and would be interested in maintaining it medium to long term, please consider contributing it to the GitHub repository, it would be gladly accepted.

As of March 2013, openFrameworks has official makefile support for compiling the library itself. However, at the time of this writing, the changes haven't yet been merged into the stable release. You'll need to clone the Git repository and switch to the development branch.

git clone https://github.com/openframeworks/openFrameworkscd openFrameworks && git checkout developcd libs/openFrameworksCompiled/projectmake

As far as I can tell, we still need to use the unofficial solutions for compiling apps against the library.

You need Xcode, or at least a set of compilers (more information is available here), but otherwise, no, you can edit/work with the code in whatever editor or environment you want.