double-buffering with buffer_region extension

OpenGL OpenGL: Basic Coding
1

I’m a bit unclear on the use of wglCreateBufferRegion with double buffering. It works the way I expect when I stick to the front buffer, but it doesn’t work when I try to save/restore the contents of the back buffer.

This works:

  1. CreateBufferRegion with WGL_FRONT_COLOR_BUFFER_BIT_ARB
  2. Draw the scene to the back buffer, swap buffers, and then SaveBufferRegion
  3. RestoreBufferRegion brings back my scene

This doesn’t work:
1)CreateBufferRegion with WGL_BACK_COLOR_BUFFER_BIT_ARB
2) Draw my scene to the back buffer and then, without swapping buffers call SaveBufferRegion.
3) Call RestoreBufferRegion and then swap buffers. Scene doesn’t update.

If a region was created for the back buffer, shouldn’t restore put it back into the back buffer?