POV-Ray : Newsgroups : povray.beta-test : Severe Lightbug, probably concerned with Macros... (long post) : Re: Severe Lightbug, probably concerned with Macros... (long post) Server Time
15 Aug 2022 14:29:55 EDT (-0400)
  Re: Severe Lightbug, probably concerned with Macros... (long post)  
From: Mike Williams
Date: 22 Jan 2002 04:23:17
Message: <HJJGdDAg7ST8EwQc@econym.demon.co.uk>
I confirm that there is some sort of a problem with the lighting.

I've stripped down the scene to about the minimum that reproduces the
problem, and it turns out it can be reproduced without macros. The key
factor is probably the two rotated turbulence warps in the normal. 

Change the amount of rotation in either of the "rotate"s and the
lighting changes.

Remove the second warp turbulence and the problem goes away.

Increase the height of the light_source and the effect is reduced.

The problem does not occur in POV 3.1g.

global_settings{assumed_gamma 1 ambient_light <0,0,0>}

#declare Wood =
  pigment{rgb <.95,.65,0>}
    warp{turbulence 1} rotate x*90
    warp{turbulence 1}
 rotate y*220

light_source{<0,0.05,0> rgb 1}

camera{location <.15,.15,-.05> look_at <0,0,0>}

cylinder {0,0.05*y,0.01 
 texture {Wood}
 translate <0,0,0.09>}

plane{y*1,0 pigment{rgb y}}

Mike Williams
Gentleman of Leisure

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