Drawing with OpenGL from other application


I have an OpenGL application which draws a 3d world and I’m looking for a way to draw some 2d pictures and strings above this 3d world. The OpenGL application has been developed by a company and I can’t modify it.
There are programs like Fraps which are able to show the frame rate within the rendering window, so there must be a way, but unfortunately I don’t know how.

Can you help me or give me useful links?
Greets, idontwantaname

hehe someone wants a better hud ? :smiley:

can I ask what sort of application is it ?

you need to code (or find some source of) a GL dll wrapper, named opengl32.dll, sitting on the same directory as the GL app .exe, and recode the swapbuffers to do your drawings right before the real swap.

No, I don’t need a better hud :wink:

I’m working at a research company which owns a driving simulator. Unfortunately there are some missing features we would need, e.g. displaying a string within the simulation.

Can this wrapper dll just have this one specific method or do I need to wrap every OpenGL procedure and function?

Greets, idontwantaname

This is a Windows application right ?
Some tools able to intercept transparently opengl calls :

No idea if a full wrap is needed or not…