SDL 2.0: Create window in main thread, but do all rendering in separate one

I have an app which runs on Mac/iOS/Windows that is structured this way (all GL in a rendering thread), but I don't use SDL.

I just took a look at SDL's Cocoa_GL_CreateContext (called by SDL_GL_CreateContext on OS X) and it makes calls that I make from my main thread to set up the context.

So, if you hit any problems, try creating the GL context in the main thread and then pass that off to the rendering thread (instead of creating the GL context in the rendering thread).

OpenGL and multithreading are basically enemies : only one thread can 'own the render context' at any given moment - yes, you can switch the GL render context whenever threads switch, but think of the cost, and also consider that, from one OEM driver to the next, it's not well supported and likely to work for some people and not others.The only logical (and sane) alternative, is to keep all your OpenGL calls to one thread (note: there are exceptions, there are things that any thread can call in gl, relating to streaming data, without them needing to own render context).Unfortunately, we can't simply pass the GL context around threads as suggested, we must call (w)glMakeCurrent, which tells GL "this caller thread now owns you", but fails to tell other threads that...