POV-Ray : Newsgroups : povray.binaries.animations : radiosity in animation-- a partial solution to 'flicker' : Re: radiosity in animation-- a partial solution to 'flicker' Server Time
23 Oct 2021 22:10:56 EDT (-0400)
  Re: radiosity in animation-- a partial solution to 'flicker'  
From: William F Pokorny
Date: 4 Dec 2020 09:51:50
Message: <5fca4d06$1@news.povray.org>
On 12/4/20 9:06 AM, Kenneth wrote:
> "Mr" <nomail@nomail> wrote:
> 
...
> 
> C1 6.40944 0 10.2727 7ffe7f 0.5393 0.5634 0.6627 0.0673439 2.02194 13b2aa
> C1 5.07783 0 9.9777 7ffe7f 0.2932 0.2820 0.3779 0.0626854 19990.9 94c3e8
> C2 4.67263 2.28262 10.8619 fd7f6d 0.2772 0.0367 0.0002 0.123517 2.80274 c81887
> C1 5.22191 0 9.92912 7ffe7f 0.3809 0.2062 0.1807 0.0629131 2.52627 63f2ae
> C1 5.40516 0 9.95757 7ffe7f 0.5724 0.6442 0.7586 0.0635047 19991.6 90cde2
> C1 5.59453 0 9.99461 7ffe7f 0.4496 0.4617 0.5039 0.0641466 1.52217 33bfce
> 
> ......etc. etc. Each line starts with C1 or C2. (And there's no obvious 'order'
> to
> the entries.) I have no idea what the data actually means.
> 

I dug up the source code not too long ago and made these notes:

---
C seems to stand for color. (There are other unused classifications)
The number after the D is depth. I've only ever seen 1 or 2 - maybe if
recursion depth increased?

The next three float values are the location.

The text string in position 5 is the normal encoded for +-(2 byte 
value/254) it looked.

Positions 6,7 and 8 are the three color channel values at the point.

In field 9 we have the harmonic mean. The inverse of the mean of the 
inverses of distances to all samples used to set a point's "radiosity 
view." This read as a double (long float) but later used in calculations 
as a float.

In field 10 the nearest sample distance found is recorded.

Field 11, like the normal field, is a string representing 3 x,y,z values 
pointing, roughly in the direction where the nearest distance sample was 
taken.

---
The floats are all read/scanned as doubles, but the file representation 
seems to be float. The internal usage in calculations is sometimes 
(always?) cast to float. Expect this means not too much difference 
between binary file encoding (as doubles) and current text encoding. 
However, if internally stored as all doubles and all only used as floats 
- the internal representation could probably be better?

FWIW.

... Yeah, hacking the radiosity file for effects is not something I 
recall anyone doing. It could be interesting. Color shifts. By global 
locations increase or decrease intensities. Insertion of samples by 
interpolation from existing ones? Completely contrived radiosity files
with gradients or whatever...

Aside: I suspect, there are some similarities to the saved photons file, 
but I've not gotten to even a first look at it...

Bill P.


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