New OpenGL Slide Transition: Tiled Flipping

Behold the new OpenGL Slide Transition! Tile Flipping! The transition splits the slide into an n by m field of rectangles, and then flips each rectangle over to reveal the the entering slide on the back side! TA-DA!
My Aspect ratio problems have been fixed, but it's a little bit too hack (clamp all animations to the portion of the screen the entering and leaving slides will occupy) so I'll be fixing that this week to allow for future transition authors to draw the slide zooming around the entire window (as long as it hopefully ends up where the entering slide should be).
If you'd like to find out how much difficulty (or lack there-of) I had adding a 3d transition system to Impress, come to my Case Study presentation at OOoCon2007 entitled: 3D Slideshow Transitions: Adding OpenGL-Accelerated Transitional Effects For Impress.
And without further ado. PICTURES!