WGL_ARB_buffer_region2? - vendors please comment

a simple question for the hardware vendors who are members of ARB:

what is the possibility (or difficulty) of adding a function such as wglSaveSubBufferRegionARB that can take a portion of the frame buffer and save it to a sub-region of an EXISTING buffer region object?

right now, you can save a portion of the frame buffer to an object, and restore whole or parts of the object back to the frame buffer, but there is no way to “update” an existing object (this is analagous to the behavior of glTexImage and glTexSubImage).

this means there is no way to do an incremental update of a buffer region. it seems like a logical feature to have, especially considering similar behavior exists in wglRestoreBufferRegionARB.

to get this behavior, i will have to resort to skillfull manipulation of pixel buffers, instead of the more elegant buffer region.