Multithreaded Rendering on OpenGL

I have a multithreaded application, in which I'm trying to render with different threads.

DON'T!!!

You will gain nothing from trying to multithread your renderer. Basically you're running into one large race condition and the driver will just be busy synchronizing the threads to somehow make sense of it.

To gain best rendering performance keep all OpenGL operations to only one thread. All parallelization happens for free on the GPU.

I suggest to read the following wiki article from the OpenGL Consortium.

In simple words, it depends a lot on what you mean for multi threading in regards to OpenGl, if you have one thread doing the rendering part and one (or more) doing other jobs (i.e. AI, Physics, game logic etc) it is a perfectly right.

If you wish to have multiple threads messing up with OpenGL, you cannot, or better, you could but it will really give you more troubles than advantages.

Try to read the following FAQ on parallel OpenGL usage to have a better idea on this concept:

http://www.equalizergraphics.com/documentation/parallelOpenGLFAQ.html

In some cases it may make sense to use multiple rendering contexts in different threads. I have used such a design to load image data from filesystem and push this data into a texture.