Re: How to determine maximum frame buffer size?

I'm not sure if there's anything beyond GL_MAX_VIEWPORT_DIMS available (a
lot of help I'm sure).

I suspect the reason that using the limits returned by that is giving you
problems is down to simple lack of memory. With a 4096x4096 buffer you're
talking 16MB for each byte of framebuffer. If you've got a 32bit (RGBA)
colour buffer, that's 4bytes, multiply that by two if you're double buffered
(that's 8) and then perhaps another 2-4 for depth buffer and stencil buffer