Alain wrote:
> Nathan Kopp nous apporta ses lumieres en ce 2007/12/12 20:01:
>> stbenge wrote:
>>> Hi,
>>>
>>> Can anyone tell me if there is a way to achieve additive transparency 
>>> for images? I'd like to update my 'luminous bloom' file, since the 
>>> current version tends to bleed dark colors as well as light ones.
>>>
>>> A media box works, but it is much too slow. I wish there was an 
>>> 'addition' pigment to complement the average pigment.
>>>
>>> Sam
>>
>> Try this:
>>
>>   image_map {
>>     ...
>>     transmit all 0.5
>>   }
>>
>>   finish {
>>     ambient 2.0
>>     refraction 2.0
>>   }
>>
>> The "transmit 0.5" and "refraction 2.0" work together to give you 100% 
>> transmittance.  The remaining 50% (left over from the transmit) 
>> combines with "ambient 2.0" to give 100% illumination.
>>
>> -Nathan
> Please note that refraction in the finish block is deprecated and may no 
> longer be supported in future versions. It should be moved to the 
> interior block.


True.  But until then, this little hack works great.  :-)

Note that the version of "refraction" found in the interior block (the 
"correct" place) does not support this hack.

-Nathan

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