BSP trees and OGL's default rendering

What’s the basic difference between what a BSP tree does and what OGL’s default depth sorting does? Right now I can give OGL a bunch of polys and it can render them all in the correct order of depth and the image looks fine.

I noticed the rendering is much slower than say, the Quake3 engine. I hear a BSP tree would speed this up, so is a BSP tree more than just a way to sort polygons?


use of bs-partitioning to raster your
geometry in back-to-front (or such) order doesn’t speed up your performance much, althought you can disable z-buffer.

but, the main benefits comes from speed of collision detection and efficient geometry clippings.