POV-Ray : Newsgroups : povray.general : image_map & interpolate ? : Re: image_map & interpolate ? Server Time
9 Dec 2021 09:04:23 EST (-0500)
  Re: image_map & interpolate ?  
From: William F Pokorny
Date: 21 Nov 2021 09:07:11
Message: <619a528f$1@news.povray.org>
On 11/21/21 7:50 AM, tth wrote:
> 
> Hello.
> 
> I'm looking at interpolate in the wiki, and I've not found the
> option for "no interpolate", is there a reason for that ?
> 
> https://wiki.povray.org/content/Reference:Bitmap_Modifiers
> 
> I'm trying to map a low-res picture as pixel-art.
> 
> 
> tTh
> 

Hi.

IIRC, With official POV-Ray versions, to get no interpolation - with 
image maps - the only way is to not use the interpolate keyword. The 
parser doesn't allow 'interpolate 0' with image maps though this is the 
no interpolation value internally.

POV-Ray is set up inconsistently with respect to the interpolate 
keyword. It sometimes supports a '0' no interpolation mode (ie density 
files) and other places not. The differences in specification method are 
for no reasons I can see(1).

Bill P.

(1) - My playpen povr branch supports 'interpolate 0' for no 
interpolation everywhere.

Aside: There is often good reason to turn off interpolation. Performance 
in development renders and where the image maps are already larger than 
the as rendered resolution being others. In not always supporting a no 
interpolation mode 'value', POV-Ray makes switching between no 
interpolation and interpolation awkward.


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