Lutz-Peter Hooge nous apporta ses lumieres ainsi en ce 04/08/2004 
04:26... :

>Rick Measham <nomail@nomail> wrote:
>  
>
>>The ceiling in my office is white. And when it's light outside it looks
>>white (radiosity aside). However when I turn the light on and I look
>>directly at the light, the ceiling looks dark. I'm guessing this is because
>>my eyes are dilating due to the large amount of light pouring in.
>>
>>In POV-Ray, is it possible to automate this?
>>    
>>
>
>IMHO it is not possible to automate it inside of Povray, since when it is
>is tracing Pixel (1,1) is does not yet know what brightness the rest of the 
>picture will have, so it can't compensate for it at this point.
>
>So you will have to do this manually (most practical for still images),
>or with postprocessing.
>
>For postprocessing, a version of Povray that doesn't clip colors and outputs
>to a high dynamic format range format obviously would be optimal, but I don't
>know if such a version is available.
>
>Lutz-Peter
>  
>
If outputing to PNG or PPM, you can set the bit-per-chanel to anything 
from 5 to 16 (default is 8). If you use, say, 10 bits and divide all 
your lights by 4 (or divide the diffuse and ambient values by 4), you 
can simulate a higher dinamic range. If doing this, be sure to lower the 
asc_bailout acordingly.

Alain

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