Overlay frame buffer use

Can anyone point me toward any examples or reference books that cover use of the overlay frame buffer in X-Windows?

I’m porting some IrisGL code that used:
“drawmode(OVERDRAW)” and “drawmode(NORMALDRAW)”.

I’m doing fine drawing in the normal framebuffer using glXChooseVisual. Reading that man page, it looks as if GLX_LEVEL specifies which buffer you want to draw to. But I’m just guessing when it comes to how to use that visual to connect a different context to my window.

Thanks,
-ed

One last plea… Anyone know anything about this?
Thanks!

Dear

If you are working on SGI machines, your don’t need to search anywhere.All SGI versions, with IRIX o/s comes with an insight Online Tutorials. Just Type insight in the command prompt. You can find rich materials on IRIXGL Poring

Thanks
Rajesh.R
IRIS,CAIR, Bangalore
(rajeshr@cair.res.in)