POV-Ray : Newsgroups : povray.beta-test : Heightfield bug (most probably an inverted normals problem) : Re: More info Server Time
2 Dec 2023 13:45:04 EST (-0500)
  Re: More info  
From: Warp
Date: 22 Jan 2002 12:21:40
Message: <3c4d9fa4@news.povray.org>
Warp <war### [at] tagpovrayorg> wrote:
:   However, I understand that removing this inversion could actually break
: something else which currently works.

  By the way, it occurred to me what would this seriously break: If we are
looking at an object surface from one side and a light source is illuminating
the object on the other side, this normal inversion takes care that we see
a shadowed surface, not an illuminated surface. If the normal was not inverted,
then the surface would work like it was double-illuminated all the time if
the unmodified normal points at the light source and it wouldn't be illuminated
at all (no matter where you look at it) if the unmodified normal points away
from the light source.

  What a dilemma!

#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -

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