clipka <ano### [at] anonymousorg> wrote:
> The attached image (1) shows the effect of interpolation on images; from
> left to right:
>
> - "interpolate 0", i.e. no interpolation
> - "interpolate 2", i.e. bilinear
> - "interpolate 3" (currently not supported)
> - "interpolate 4", i.e. normalized distance
>
> In all cases, the black dot is exactly at the center.
>
> As can quite easily be seen, when interpolation is activated the image
> appears slightly shifted to the bottom-right, in the order of magnitude
> of half a pixel.
>
> Normally I'd just fix that offset, but it has probably been there since
> eons - and changing it might actually break a few scenes that have
> deliberately worked around this issue (I have at least once designed
> such a scene).
>
> How do you feel about it?
>
> My personal vote would be to fix it nonetheless, to end up like shown in
> the attached image (2). (And yes, that's bicubic interpolation you see
> in the "interpolate 3" field.)

I've got code to correct for this in my DF3 Proximity macros - the same problem
affects voxels with interpolation. I can change my macros if you change POV, but
is there a way to query a specific sub-version of POV? Can I query if I'm
running beta 37 vs beta 38?

Also - are you sure its a bug? I managed to convince myself that it's the
correct behavior if the pixel's value is defined for the pixels coordinate (e.g.
<0,0>, <1,4> or <1023,1023>) rather than half a pixel across (e.g. <0.5,0.5>,
<1.5,4.5> or <1023.5,1023.5>). Does that make sense?

Cheers,
Edouard.

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