RE: [Algorithms] I hate mirrors...
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From: Chris B. (BUNGIE) <cbu...@mi...> - 2002-09-20 21:09:04
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You are correct that the adjusted near clip plane technique breaks down when the view direction is nearly perpendicular to the plane of the mirror. But we've found that you can hack around it to produce a clip plane which is good enough to be usable. The trick is to rotate the plane of the mirror as the camera's incident angle approaches zero, so that the incident angle never goes below some amount. Unfortunately this means that you can never get the nice Taj-Mahal-reflected-in-the-pool visuals, for which you would presumably need to create a different kind of mirror. The other problem is that we never effectively used this technique in Halo because we ran out of time. There *are* mirrors, but they're not in glaringly obvious places and 99% percent of people will miss them. Oh well. If anyone did actually notice them, I'd appreciate a little-r reply. :) -- Chris Butcher Rendering & Simulation Lead Halo 2 | Bungie Studios bu...@bu... =20 -----Original Message----- From: Wesley Hunt [mailto:hu...@cs...]=20 Sent: Friday, September 20, 2002 11:57 To: gda...@li... Subject: Re: [Algorithms] I hate mirrors... ----- Original Message ----- From: "Mat Noguchi" <mat...@mi...> To: "Tom Forsyth" <to...@mu...>; <gda...@li...> Sent: Friday, September 20, 2002 1:25 PM Subject: RE: [Algorithms] I hate mirrors... > With proper culling, the bits farther away shouldn't draw. > I don't think this works. like mentioned earlier, you really need an interval ztest for this to work, where one is the plane of the mirror, and the other is the current zvalue. > Of course, it's infinitely easier to just adjust the near clip plane to > lie along the mirror (along with the far clip to be parallel to that). > I've played around with this method, but I couldn't get it to work right when your view direction faces away from the plane of the mirror. If you think about what this techniue does, you can't skew the near plane enough if your view direction is not facing towards the mirror by some amount. Has anyone found a solution for this? -Wes |