POV-Ray : Newsgroups : povray.newusers : UV texture scale center : Re: UV texture scale center Server Time
30 Apr 2024 22:04:41 EDT (-0400)
  Re: UV texture scale center  
From: clipka
Date: 24 Jan 2015 15:19:31
Message: <54c3fe53$1@news.povray.org>
Am 24.01.2015 um 15:30 schrieb clipka:

>> map_type 0  interpolate 2 } translate <0.25,0,-1> scale <1.5,1,1>]
>
>                                          ^^^^^^^^^^^
> Beware - you're moving the texture here, not just scaling it!
>
> Note again that scaling /always/ has its origin at <0,0,0>; if you do
> this /after/ translation, it's no longer the <0,0> of the image, but
> rather its <-0.25,0>. To scale from the /image's/ <0,0>, you need to
> scale first, and only then translate; you'll probably need to fix the
> translation vector though:
>
>      scale <1.5,1,1> translate <1.5,1,1>*<0.25,0,-1>

I think I wrote nonsense here: Translating after scaling, but with the 
scaling factor applied to the translation, has /exactly/ the same effect 
as your translating before scaling.

The proper question here would be, why is there a translate in there at 
all, and exactly what effect is it supposed to have?


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