Path: chuka.playstation.co.uk!news From: "Tyrone McAuley" Newsgroups: scee.yaroze.programming.3d_graphics Subject: Re: Point light sources Date: 2 Aug 1997 11:11:56 GMT Organization: PlayStation Net Yaroze (SCEE) Lines: 59 Message-ID: <01bc9f36$66022c00$ce3261cb@beast> References: <01bc9297$19d2e5a0$733261cb@beast> <33CDFDB1.66D7@interactive.sony.com> <01bc981d$7d0849e0$903261cb@beast> <33DF0559.64BEAFB5@micronetics.com> NNTP-Posting-Host: d3-u14.wgtn.clear.net.nz X-Newsreader: Microsoft Internet News 4.70.1155 Jim wrote in article <33DF0559.64BEAFB5@micronetics.com>... > Tyrone McAuley wrote: > > > > > > So we simulate point light sources by manipulating the normals of objects > > in > > relation to a parallel light source which is pretending to be a point light > > source. > > (I guess thats what you mean). > > > > This is an idea I was toying around with last night, after deciding that > the light model in gslib is pretty much useless. I want to light up a > rather small area of a map, for an explosion, gun fire, etc.. > > Presently the way I think its going to go is to just point the polygon > normals around the explosion towards the lightsource vector, the normal > should just be the inversion of the light vector. It should brighten > the ajoining polys quite neatly. Fortunately the tmd normal data is not > used for culling. > > You have any pratical experiance with this on the Yaroze? Ideas? > Is there an easier way to just illuminate a small section of a model? > > Cheers > JiM > We haven't really set about implementing it (too many other things to do at the moment), but we have been talking about it (we will do it eventually). You have the right idea, but remember that because we don't have access to the hardware you will have to set up a dummy flat light to actually light the polys and therefore need to do an extra transformation on your normals in relation to this light. Unfortunately this technique will not let you mix flat and point light sources. You should be able to get some nice effects with a combination of ambience, fogging, and point light sourcing though. We haven't come up with an alternative way of getting this effect yet. Perhaps you could look at hacking the TMD structure or lighting model or something (not easy without more hardware knowledge though). Let me know how you get on. Mario Prodigy Design Ltd