POV-Ray : Newsgroups : povray.general : Bug in pseudo random? (gif 716b+) : Bug in pseudo random? (gif 716b+) Server Time
12 Aug 2024 13:19:03 EDT (-0400)
  Bug in pseudo random? (gif 716b+)  
From: Spider
Date: 2 Feb 1999 11:18:38
Message: <36B7240F.665C19A0@bahnhof.se>
Well, I was playing around in pov, using rand() and seed() functions
when I found this little effect after using it a bit.

The original idea was to ues the Superpatch in a few aspects(place a lot
of sphres and use bouded_by from a text object, and thus get text made
out of bubbles, generally.) when this effetc appeared, I made some
changes, and switched to normal pov to see if it was still there. Sure
it was.

Well, this is the code for the scene :

camera { location<0,0,-10> look_at<0,0,0> }
light_source { <-50,150,-50> color rgb 1 }
light_source { <+50,150,-50> color rgb 1 }

union {
  #local Min = <0,-0.0286, 0>+0.1;
  #local Max = <10,1.6721,4.6715>-0.1;
  #local S = <seed(1), seed(2), seed(3)>;
  #local R = seed(4);
  #local N = 0;
  #while(N<10000)
    sphere {
      Min+(<rand(S.x),rand(S.y),rand(S.z)>*Max)
      (rand(R)*0.07)+0.03
    }
    #local N=N+1;
  #end
  translate -5*x
  pigment {colour rgb 1 }
  finish {ambient .8}
} 
At first I thought it was the #local S = <seed(1), seed(2), seed(3)>;
line that was in error, but no. This worked with other numbers, so the
error is in seed(1) seed(2) seed(3) generation. 

I just wonder if there is a limitation in the seed() function causing it
not to work with theese small numbers ???

If i used a a larger set of numbers, 666, 1999, 2010 3010 and so, it
worked nicely, but not here.

Attached is a .gif of the image, 2 colours.
I'm sorry about the image, but I thought it was small enough to be
attached here. *smile*

//Spider


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