[SDL] off-screen buffer for openGL in SDL?

[PRESTON,JOSEPH S]

Hi, sorry if this question is answered somewhere in the 
documentation, but I've looked and so far haven't found anything.

I need to create an off-screen buffer for openGL that is 
(slightly) larger than the window I'm drawing--I'm doing some 
image warping, and will be using the larger image as a texture, 
doing some warping, and drawing it to the main window.  Using 
double-buffering, though, I can only draw an image as large as the 
current window size.  I need something similar to a pbuffer in 
wgl, and was wondering if SDL supports something like this (I've 
been using GLUT until now, and it doesn't seem to).  I can create 
a SDL_Surface, but I don't see a way to initialize this for openGL 
drawing or set it as the current buffer to draw to.  Thanks.

-Sam Preston