Usefull Info about Fast Occlusion and Culling

[katoun]

Please read this page is very nice and usefull:
http://www.gamasutra.com/features/20020 ... ik_pfv.htm

[Electron]

Cool. I definitely think someone should work on implementing this. Perhaps I will when I get the time (though if I do it I'll probably do it for Lightfeather). My portal and pvs culling systems made me fairly confident about being able to have large indoor levels at decent speeds, but I hadn't thought much about outdoor ones. I have read about occlusion volumes before, but never in detail about how to implement them. The article says htey should be placed in a 3d package or level editor though. With some culling methods, such as portals, that is really the only way, but I think occlussion volumes could be generated automatically, though admittedly a CLOD system would probably be needed to do it. Also note that there are some hardware occlussion tests possible on most gpus (radeon 8500 and up, gforce 3 (I think)and up). I forget the exact code needed but it involves taking the aabb of an object ot be rendered and testing (but not actually writing) the zbuffer with it. If the zbuffer is modified, then render the actual object. If its not, then the object is occluded. I've never actually implemented this method though and I don't know exactly how fast it is.

[katoun]

As I might say, I think the cost for procesing the ocluders is a lot smaler than the cost of rendering the unecesary poligons and this only for outdoor scenes so the efficiency of this method is pozitive and it's limit is not 0 or near 0.