bsp-trees..... what are they used for? since i''m using opengl i have a hardwareaccellerated z-buffer... why shold i need bsp-trees? There are obviously something good about them since quake 3 uses them for there maps.. Can someone please educate me in this subject... // Thanx in advance, Ankan

If I were you, I would check back through previous threads. This topic has been discussed extensively with links and more. There is also a bsp faq at Gamedev.net . Hope this helps.

-Andreas

Think about it this way. When you are using a z-buffer you are still transforming and drawing all of the polygons in your scene.

If you use a BSP tree to cull (remove) all of the polys that cannot possibly be viewed then you will cut down on the amount of transformations that need to be performed and your program will run faster.

The z-buffer merely makes sure that those polygons are drawn in the correct order. It does not determine which ones should be drawn. For more info on BSP trees I recommend Michael Abrash''s Graphics Programming Black Book. There is a section on BSP trees and insights on how he and Carmack solved various problems relating to Quake.

I hope this helps.

Robert McHugh