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From http://www.povray.org/download/3.5-bugs.php
http://news.povray.org/3bb4cf08@news.povray.org
<QUOTE>
// camera in front of box:
camera {location -2.5*z look_at 0}
// light_source behind box:
light_source {1000*z, color 1}
background {color <0.6,0.8,1.0>}
box {
<-1,-1,0>, <1,1,0>
</QUOTE>
I think this is a case of the 'coincident surfaces problem'.
It suffices to thicken a little the box and the highlights
are no more visible.
Massimo
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> I think this is a case of the 'coincident surfaces problem'.
> It suffices to thicken a little the box and the highlights
> are no more visible.
Put the camera inside the box, where obviously no light can reach, and
you'll still see the problem. It is a legitimate bug, although using a flat
box probably wasn't the best way to report it.
Its sister bug is the "shadow line artifact" bug. They're both caused by
similar flaws in the same algorithm.
- Slime
[ http://www.slimeland.com/ ]
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Slime <slm### [at] slimeland com> wrote:
> Put the camera inside the box, where obviously no light can reach, and
> you'll still see the problem. It is a legitimate bug, although using a flat
> box probably wasn't the best way to report it.
> Its sister bug is the "shadow line artifact" bug. They're both caused by
> similar flaws in the same algorithm.
I'm not very comfortable about using the word "bug" in this particular
case.
Your last definition, "flaw in the algorithm" is a much better expression
IMHO.
As I define it, a bug is either a programming mistake, or an implementation
mistake. That is, a bug is always a mistake made by the programmer.
These artifacts are not mistakes. They are flaws in the algorithms. The
implementations of the algorithms work exactly as supposed to. The flaws
are known (the programmers probably weren't aware of these flaws when
they coded the algorithms, but they didn't make any *mistake* per se when
coding).
There are ways to overcome these flaws and limitations, but I wouldn't
call that "bug fixing". I would call it "improving the algorithm".
--
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -
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