POV-Ray : Newsgroups : povray.advanced-users : What do vista and light buffers do? Server Time
30 Jul 2024 04:21:35 EDT (-0400)
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From: Ron Parker
Subject: Re: What do vista and light buffers do?
Date: 31 Aug 2000 12:28:07
Message: <slrn8qt2me.2jb.ron.parker@fwi.com>
On Thu, 31 Aug 2000 09:17:50 +0300, Peter Popov wrote:
>On 30 Aug 2000 23:55:38 -0400, ron### [at] povrayorg (Ron Parker)
>wrote:
>
>>>: The vista buffer is a 2-d representation of the locations of the objects in 
>>>: the scene, as seen from the camera.
>>>
>>>  How does povray determine those 2D areas?
>>
>>By projecting the bounding boxes onto a sphere, I suspect.  I've never looked.
>
>That's one way to put it but maybe it only stores the bounding box
>vertices in spherical coordinates with respect to every light source?

I fail to see a difference between what I said and what you said.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.


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From: Ron Parker
Subject: Re: What do vista and light buffers do?
Date: 31 Aug 2000 12:44:06
Message: <slrn8qt3kd.2jb.ron.parker@fwi.com>
On 31 Aug 2000 12:28:07 -0400, Ron Parker wrote:
>On Thu, 31 Aug 2000 09:17:50 +0300, Peter Popov wrote:
>>On 30 Aug 2000 23:55:38 -0400, ron### [at] povrayorg (Ron Parker)
>>wrote:
>>
>>>>: The vista buffer is a 2-d representation of the locations of the objects in 
>>>>: the scene, as seen from the camera.
>>>>
>>>>  How does povray determine those 2D areas?
>>>
>>>By projecting the bounding boxes onto a sphere, I suspect.  I've never looked.

I was wrong.  It projects the bounding boxes onto the faces of a box.  I 
suspect it's done this way because planar polygons are easier to deal with.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.


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From: Tony[B]
Subject: Re: What do vista and light buffers do?
Date: 31 Aug 2000 17:20:54
Message: <39aecc36@news.povray.org>
> (as in my unique IRTC entry 2 years ago:
> http://oz.irtc.org/ftp/pub/stills/1998-08-31/afterain.jpg


Hey, that's really beautiful... got the source code? :)


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From: Nicolas Calimet
Subject: Re: What do vista and light buffers do?
Date: 1 Sep 2000 04:13:12
Message: <39AF678D.7A745AB3@free.fr>
> Hey, that's really beautiful... got the source code? :)

	Thanks ;-)
	Source code is given on the IRTC website (www.irtc.org)
if you look to the July-August 1998 results for still images;
alternatively you can get the .zip directly from here:

http://oz.irtc.org/ftp/pub/stills/1998-08-31/afterain.zip

	Beware that it needed more than 4 days to render on a
fast machine at that time (was a Digital Alpha) because of the
atmosphere effect combined to focal blur. I didn't tried to
render it again, but it should be at least as long on a PC
PIII/500. Could be a little faster if using +ul switch to turn
on light buffers, but then it requires about 250 MB of memory :-)
	For more details:

http://oz.irtc.org/ftp/pub/stills/1998-08-31/afterain.txt


*** Nicolas Calimet
*** http://pov4grasp.free.fr


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From: Peter Popov
Subject: Re: What do vista and light buffers do?
Date: 2 Sep 2000 04:26:44
Message: <aqluqsk1rpk1j3s80lpabonrojiv792op0@4ax.com>
On 31 Aug 2000 12:28:07 -0400, ron### [at] povrayorg (Ron Parker)
wrote:

>>>By projecting the bounding boxes onto a sphere, I suspect.  I've never looked.
>>
>>That's one way to put it but maybe it only stores the bounding box
>>vertices in spherical coordinates with respect to every light source?
>
>I fail to see a difference between what I said and what you said.

There might be none, it's just that when I read "projected onto
something" I still see that something as an object in 3D and thus the
points on it have 3D coordinates. Technically, though, you're right,
there's no difference, it's just the way it sounds.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] usanet
TAG      e-mail : pet### [at] tagpovrayorg


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