Path: chuka.playstation.co.uk!news From: Craig Graham Newsgroups: scee.yaroze.mydemos Subject: Re: Demo competition Date: Wed, 30 Sep 1998 12:35:27 +0100 Organization: PlayStation Net Yaroze (SCEE) Lines: 32 Message-ID: <3612177F.E71390C9@hinge.mistral.co.uk> References: <360D2E59.C32F9DA@scee.sony.co.uk> <36120183.343164DA@scee.sony.co.uk> NNTP-Posting-Host: d2-s3-97-telehouse.mistral.co.uk Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.05 [en] (Win95; I) James Russell wrote: > > > o Bump-mapping (shaddup your face, Colin H! :O) > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > What does this mean?!? I know real time bump mapping would be tricky > > on a piss poor 30 MIPS processor, but do-able. Does Colin have some > > tips, using the GTE or something? > > Actually, Colin thought up a way of doing it using an 8 bit CLUT animation and practically zero CPU > time, but neither of us have got around to implementing it - my claims of "I'll have it done > tonight" have caused him to give me a bit of stick, and now he's accusing me of 'sub-contracting' > the problem. Bump mapping is very rarely done in the 'realistic' way that a raytracer might do it > (i.e. calculating the normals and perturbing them, etc). If you check the sources available, you'll > probably find that a few clever applications of semi-trans textures would give an identical effect. Demo style cheat for this one.... 1) Load multiple pre-modified copies of the clut (how many depends on how realistic you want it to be). You'll want to write a quick routine to calculate these from the bump map texture for the main texture.... 2A) Modify the CBA of the Bump mapped polygons to point to a clut using indexed from one component of the objects work matrix multiplied by the polygons face normal vector. 2B) Cheat a bit, only rotate around one axis and index the CLUT directly from the rotation. I assume that's how you were gonna do it James? Maybe not, but if you're only trying to get the effect in a demo (not a game), then you can afford to waste loads of VRAM space to get the effect..... > == James_Russell@scee.sony.co.uk +44 (171) 447-1626 Craig.