POV-Ray : Newsgroups : povray.text.scene-files : parallel looks_like test scene : Re: parallel looks_like test scene Server Time
24 Feb 2024 17:21:41 EST (-0500)
  Re: parallel looks_like test scene  
From: clipka
Date: 12 Sep 2016 11:59:16
Message: <57d6d0d4$1@news.povray.org>
Am 12.09.2016 um 16:42 schrieb Mike Horvath:
> In this test scene the light source is stuck at the horizon when it
> should be up in the sky.

But the looks_like object is translated perfectly fine.

What you see is the highlight remaining unchanged; but the highlight
doesn't show where the light source's nominal position is -- it shows
the direction the light is coming from.

And that direction is unchanged: With a parallel light source, the
direction of all light rays depends only on the /relative/ location of
two points: The light source's nominal center and the point_at
parameter. But transformations act on both these points (I've just
checked the code), so a translation operation changes only the absolute
location of the points, not their relative location to one another. And
thus the light direction remains unimpressed.

(BTW, point_at defaults to <0,0,1>.)

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