> that maps OpenGL primitives onto SQL result sets

Here is a set of vertices, now draw me a 2d image that represents the 3d scene those vertices represent from a certain viewpoint.

It boggles my mind that this logic can be twisted into running arbitrary SQL logic. Does it actually do something as magic as overlying SQL set logic onto a graphics scene...where the results of the SQL query are equivalent to the set of vertices that are calculated to not be visible when rendering the scene? Amazing stuff.