Path: utzoo!utgpu!water!watmath!clyde!bellcore!tness7!tness1!sugar!peter From: peter@sugar.uu.net (Peter da Silva) Newsgroups: comp.sys.amiga.tech Subject: Re: IFF form for 2D drawings (again) Message-ID: <2435@sugar.uu.net> Date: 11 Aug 88 01:48:33 GMT References: <11640003@hpfcdc.HP.COM> <11640004@hpfcdc.HP.COM> Organization: Sugar Land Unix - Houston, TX Lines: 16 In article ... cunniff@hpfcdc.HP.COM (Ross Cunniff) writes: > Actually, every object *is* rotatable; simply rotate the actual points > of the data. ... My rationale for precomputing the rotation is that > it is faster to render objects whose position and rotation are precomputed > rather than rotating and traslating them on the fly... That's fine for a rendering standard. I thought, though, that you were working on a data transmission standard. For that, the rotation angle is important. Why? Floating point operations are not commutative. The rotated points for the rectangle will be off by a small amount, whereas the unrotated rectangle may be exact. If it's stored and transmitted in an exact format, then errors will not accumulate as the iterations progress. -- Peter da Silva `-_-' peter@sugar.uu.net Have you hugged U your wolf today?