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Re: on portals...
Posted By: Loren Petrich <>Date: 10/16/00 11:56 p.m.

In Response To: Re: on portals... (ydnar)

[on lightmapping usually being a preprocessing operation...]
> there have been realtime games (or perhaps just demos) with
> per-frame raytracing. they have been with simple models, and
> rendering a low-resolution framebuffer, however.

That's because it's computationally expensive -- one has to do a lot of hit testing to find out what is in the way. However, the usual sorts of fast 3D rendering can be interpreted as a limited sort of ray tracing -- ray tracing that ignores everything but the surface currently being rendered.

> the term 'raycast' is a throwback to pseudo-3d engines (wolf,
> doom, marathon) as a visibility determination algorithm.
> marathon, for instance, was a 'pure' portal engine in the sense
> mentioned in this thread.

Having had to wrestle with the Marathon engine's visibility code, I note that you are completely correct. Every wall between two map polygons is treated as a portal.

And I make that comment because I've had to make two sorts of changes to it:

* Increase the visibility range from half size to the full size of the world geometry.

* Replace fixed-size arrays with variable-sized arrays.

* Do some sorting by polygon of the visibility-tree nodes. This required making each node a member of two trees, a polygon one and a visibility one.

> ydnar

Nice to see you back.

Message Index


Matt's Halo Update 10/13/00Matt 10/13/00 7:45 p.m.
     Re: Matt's Halo Update 10/13/00Jex 10/13/00 7:56 p.m.
           Break the Berlin Wall!Redox 10/14/00 1:07 a.m.
                 Re: Break the Berlin Wall!Luke 10/14/00 1:49 a.m.
     Re: Matt's Halo Update 10/13/00Tom Bombadil 10/13/00 9:50 p.m.
           Do you have a problem with your name? ntCyberBob =PN= 10/14/00 2:46 a.m.
                 Who is this Tom guy?Myrch 10/14/00 11:02 a.m.
                       The guy you share an email addy with. ntCyberBob =PN= 10/14/00 3:21 p.m.
                       Re: Who is this Tom guy?instigator 10/15/00 12:08 a.m.
                             Re: Who is this Tom guy?Myrchlamydia 10/15/00 9:53 p.m.
                                   Re: Who is this Tom guy?instigator 10/15/00 10:09 p.m.
                                   Re: Who is this Tom guy?SiliconDream =PN= 10/16/00 4:05 p.m.
                                         Re: Who is this Tom guy?Myrchlamydia 10/16/00 10:05 p.m.
                                   Re: Who is this Tom guy?Baggataway 10/17/00 2:24 a.m.
     Sacré bléu!Pierre LaCoucatine 10/14/00 2:04 a.m.
           Distressing, very distressing. (nt)carb 10/14/00 3:10 p.m.
     Re: Matt's Halo Update 10/13/00Dan Rudolph 10/14/00 8:48 a.m.
     Re: Matt's Halo Update 10/13/00[OF/CO] hYlAnDeR 10/14/00 10:46 a.m.
     im glad to hear about the insides![[[willhaven]]] 10/14/00 3:27 p.m.
           Re: im glad to hear about the insides!mattD 10/14/00 6:37 p.m.
                 Re: im glad to hear about the insides!Nights 10/14/00 8:40 p.m.
                       Re: im glad to hear about the insides!mattD 10/14/00 9:48 p.m.
                             on portals...[[[willhaven]]] 10/16/00 3:27 a.m.
                                   Re: on portals...Dan Rudolph 10/16/00 9:02 a.m.
                                         Re: on portals...ydnar 10/16/00 1:23 p.m.
                                               Totally OTLouis Wu 10/16/00 1:50 p.m.
                                                     :) n/tydnar 10/16/00 2:28 p.m.
                                               Re: on portals...Loren Petrich 10/16/00 11:56 p.m.
                                         Re: on portals...[[[willhaven]]] 10/17/00 6:26 p.m.
                                   Re: on portals...Mark Levin 10/16/00 9:16 a.m.
     Re: Any Chance of getting some screenies?Massa 10/14/00 4:39 p.m.
           Re: Any Chance of getting some screenies?StarHawk*IG* 10/16/00 1:54 p.m.
     Re: Matt's Halo Update 10/13/00Judge 10/16/00 1:40 p.m.
           Re: Matt's Halo Update 10/13/00Smokey 10/16/00 1:52 p.m.
           Re: Matt's Halo Update 10/13/00Judge 10/16/00 1:55 p.m.
           Re: Matt's Halo Update 10/13/00Matt 10/16/00 4:31 p.m.
     mHalo Mods on Xbox?ZeroRage 10/16/00 3:32 p.m.
           nope.....JuJu 10/20/00 11:32 p.m.
     Xbox VS PCDevil Warrior 10/16/00 7:39 p.m.
           Re: Xbox VS PCDan Rudolph 10/16/00 9:46 p.m.
                 Re: Xbox VS PCCreedoG 10/16/00 10:03 p.m.
                       Re: Xbox VS PClummie 10/16/00 10:50 p.m.
                             Re: Xbox VS PCDan Rudolph 10/16/00 11:15 p.m.
                       Re: Xbox VS PCjon 10/17/00 1:29 p.m.
           Re: Xbox VS PCScorpion 10/16/00 9:58 p.m.
           Ahemmattd 10/16/00 10:10 p.m.
                 Re: AhemDan Rudolph 10/16/00 11:16 p.m.
                 This differences in speed, its a trade offFieldcar 10/16/00 11:30 p.m.
                       Re: This differences in speed, its a trade offspitfire 10/18/00 11:35 a.m.
                             Re: This differences in speed, its a trade offDan Rudolph 10/18/00 2:03 p.m.
           Re: Xbox VS PCPlaton 10/17/00 3:00 a.m.
                 Re: Xbox VS PCturkey3 10/17/00 10:47 a.m.
                       Re: Xbox VS PCqirex 10/17/00 7:08 p.m.
     Happy Birthday afterwards, ChuckyHonK_DICE 10/17/00 2:06 a.m.
     Release dates!!!!!!bungiefanfromwayback 10/17/00 1:52 p.m.
           Re: Release dates!!!!!!mattd 10/17/00 2:23 p.m.
           Um, noMark Levin 10/17/00 3:42 p.m.
                 Um, could you be more vague?Pumpkinhead 10/17/00 10:45 p.m.
     Re: Matt's Halo Update 10/13/00Pumpkinhead 10/17/00 11:07 p.m.
           Re: Matt's Halo Update 10/13/00Louis Wu 10/18/00 9:20 a.m.
                 Re: Matt's Halo Update 10/13/00Pumpkinhead 10/18/00 4:44 p.m.

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