Path: chuka.playstation.co.uk!news From: daniel@reichardt.ch (Daniel Hartmeier) Newsgroups: scee.yaroze.programming.3d_graphics Subject: Re: 3d world clipping Date: Fri, 20 Nov 1998 15:50:50 GMT Organization: Reichardt Informatik AG Lines: 49 Message-ID: <36558cfa.19293212@news.playstation.co.uk> References: <36552f4a.6753350@news.playstation.co.uk> <733kaq$ekm2@chuka.playstation.co.uk> NNTP-Posting-Host: empty241.magnet.ch Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Newsreader: Forte Agent 1.5/32.451 On Fri, 20 Nov 1998 11:33:25 -0000, "Peter Dollochan" wrote: > Ok here is what I'm doing at the mo' with a city project I'm doing > The objects are depth cued for starters ie they are only inserted > into the scene depending on overall distance from the camera > at the same time as you've already calculated the distance I store > 2 or 3 objects TMD's so the actual model displayed is depth cued > as well, the closer the more complex etc. If I understand you correctly, you are describing a way to use several versions of the same model (with different complexity) depending on the distance to the camera. This is something I will have to do also, but my first question is, how can I determine efficiently whether an object is visible at all, whether it lies within the visible part of my world. For instance, my camera is at 0,0,0, looking into direction 1,1,0 with a certain projection distance (or zoom factor). Now, I have an object at -1,1,0 with a bounding sphere of radius 0.25. How do I best calculate, whether it is (partially) visible. I _do_ know the maths involved, I just don't know what optimizations I should make, in order to do it in reasonable time. What data structures are used, what lists do I maintain, etc. > I messed around with only displaying objects depending on camera rotation > but whether it was my code (prolly) or just not fast enough by comparison > to the psx just drawing the lot is something you should muck around with > I didnt find it faster (but then I'm not an authority on the subject :-) > Books - look out for L.Ameeraal author...(i think i spelt it right) and the > old fav foley and van dam but its to much work for my money ;-) > or maybe just a good maths book from your local library that you > can just forget to take back 'GRIN' I checked on Amazon and CLBooks today, but most of the 3d graphics related books cover the low-level algorithms, which the PlayStation already does on its own. What I need is advice on a little more abstract level. > (just confused myself but hoping it helps a little:-) "Confidence is the feeling that you have before you understand the situation." :-) Regards, -- Daniel Hartmeier PGP 6A3A7409 ICQ# 12742482 "The woods are lovely, dark and deep. But I have promises to keep, And lines to code before I sleep, And lines to code before I sleep."