How to use OpenGL ES sharegroup to share a render buffer for screen mirroring on the iPad?

Question

I'm trying to do screen mirroring on the iPad with OpenGL 1.1. I've got to the point of setting up the external window and view. I'm using OpenGL on the first screen, and I've read that I can setup a shared render buffer, but since I'm somewhat of an OpenGL beginner I'm having some trouble getting something up and running that can share a render buffer.

I've got as far as setting up two separate contexts and rendering different things to both, but of course I would like to share the render buffer for the sake of efficiency. The Apple documentation explains how I would set up a share group object and initialize a shared context, but I would like to also know how I would go about setting up and sharing a render buffer so that the external screen can just draw this render buffer to it's frame buffer.

The eventual goal is to do the screen mirroring as efficiently as possible, so any advice on the matter would be most appreciated.

Answer 1

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I think this topic in the cocos2d forums would be a good read for you! ( Scroll down to the last posts ).

Maybe you're not using Cocos2d at all, but the information there is quite valuable, and there's some code too.

Good luck!