POV-Ray : Newsgroups : povray.programming : Att variable in lighting.cpp : Re: Att variable in lighting.cpp Server Time
18 May 2024 08:42:44 EDT (-0400)
  Re: Att variable in lighting.cpp  
From: Le Forgeron
Date: 7 Dec 2005 10:11:58
Message: <4396fbbe$1@news.povray.org>
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Jing Li wrote:
> Could you tell me what kind of attenuation of Att is, such as Light-source
> attenusation or Atmospheric attenuation, and where the original formula
> comes from?

1. Learn to quote, please.
2. Read your own text...
 the function is compute_lighted_texture, so what do you believe is
happening there ?
Att is a scalar coefficient used to dim the texture... now consider what
pFilter and pTransmit might reference, and try to draw the relevant curves.
Then look where Att is used (just a few lines after the one you cited)

the only caveat I would have about the filter mechanism is that a
texture which filter must have the same reflecting color... that's part
of the used data-design, and it is not always practical.

> Thorsten Froehlich <tho### [at] trfde> wrote:
> 
>>Jing Li wrote:
>>
>>>What is the meaning of the Att variable in method "compute_lighted_texture"?
>>>It is computed
>>>using the fomula
>>>Att = (1.0 - (LayCol[pFILTER]*max3(LayCol[0],LayCol[1],LayCol[2]) +
>>>LayCol[pTRANSM]));
>>
>>Attenuation.
>>
>> Thorsten



- --
Eifersucht ist die Leidenschaft, die mit Eifer sucht, was Leiden schafft.
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