Vbl sync for non gl games

Hi, I’m trying to portably get vbl syncing in my non 3d non gl SDL-game.
I saw SDL_OPENGLBLIT and though “wa-hey, shortcut!”, or-ed it into
the video flags, set SDL_GL_SWAP_CONTROL to 1 and added an
SDL_GL_SwapBuffers after SDL_UpdateRect(scrn, 0, 0, 0, 0).
All was good with syncing, except the play area had been shifted to the
bottom of the screen and a bit to the left.

The play area’s pretty small (512x342) and so under osx fullscreen
it gets letterboxed (however under xp on the same machine there
exists a 512x342 mode, beats me).

Is there some magical incantation I’m forgetting to invoke? Do I need
to set the rest of the gl attributes, even if I don’t ever directly call any
texture upload functions?

This was on an intel mac with the binary release 1.2.10 and 1.2.11.
Haven’t tried windows yet.

felix: lightweight threads, HOFs and game scripting.
svn co https://svn.sourceforge.net/svnroot/felix/felix/trunk felix