OpenGL without GUI

I would like to create a command line tool that uses an OpenGL Context to render using Framebuffer objects (FBO) then pulls the data from the frame buffer and saves it to an image file.

There’s not much in the way of tutorials for such a thing although I imagine it should be a simple enough operation.

basically, I have a background image I want to bring in, render my geometry on top of that and then spit out the final render into an image file.

Could someone point me in the right direction?

p.s. not sure if it matters but I’m using GNUstep

I can not be more precise, but apparently you need to create a hidden window in order to create a valid OpenGL context. Then you can do your FBO stuff.

The hidden window creation is OS dependent, so it is related to X11 in your case.

I guess there was off-screen Mesa or such that can do GL off-screen. But I’m now really unsure about that.

Otherwise what you can do is trying to never map the window on the desktop. Really unsure if it will work neither.