Path: chuka.playstation.co.uk!news From: Toby Hutton Newsgroups: scee.yaroze.programming.3d_graphics Subject: Re: creation of tmds Date: 30 Jun 1998 11:27:27 +1000 Organization: PlayStation Net Yaroze (SCEE) Lines: 25 Sender: thutton@TECH10 Message-ID: References: <354f8520.24963808@www.netyaroze-europe.com> <35527A2E.72F907B4@home.com> <6n904u$4sn1@scea> NNTP-Posting-Host: 203.103.154.235 X-Newsreader: Gnus v5.3/Emacs 19.34 jamin1@psu.edu (Jamin Frederick) writes: > > In this code and others I've seen, it looks like the TMD coordinate system is > the same as RSD coordinate system, i.e., 1000.0 TMD == 1000.0 RSD, etc. Now > are the TMD coord numbers converted to fixed point (12-bit) when it is given > to the playstation? I mean, do we have to mess around with fixed point at > all, or do we just use the system of RSD and TMD (assuming they're the same), > with vertices usually in the range of +-500.0 to +- 2000.0 or so? B/c there > are only 3 integer bits for 12-bit fixed point, meaning you can only get at > most 7.something? I was under the impression that fixed-point is used only for the normals in a TMD file. Vertices are 16 bit ints. You also need to keep in mind that the coordinate space is 32 bit, but the viewing space is only 16 bit. ie. An object can sit anywhere between -2 billion and +2 billion (I assume, haven't tried it) but if the object is more than 32k away from the view point, you won't see it. That's a reason why you shouldn't make your models too big (I saw this was a question in your FAQ). -- Toby.