POV-Ray : Newsgroups : povray.beta-test : Granite and noise gen 3 bug? Server Time
2 Nov 2024 17:20:46 EDT (-0400)
  Granite and noise gen 3 bug? (Message 1 to 3 of 3)  
From: Redbeard (MDJohnson)
Subject: Granite and noise gen 3 bug?
Date: 14 Oct 2001 12:21:27
Message: <3bc9bb87$1@news.povray.org>
I know the noise generator has been changed to remove plateaus.  However, as the
following shows, it doesn't appear to generate a full range of values (from
0-1).  I appologize if this has been mentioned and discussed already.  If so,
point me to the right spot.

If noise_generator 3 is used, the following is solid red rendered at 800x600.  I
would expect that some white (even if just flecks) would be visible, considering
it is set to 30% red.  Using noise_generator 1 works as expected.  Noise
generator 2 yields the same results as 3.

// Complete scene
sphere
{
  z * 3, 1
  pigment
  {
    granite
    #declare P = 0.7;
    color_map { [P rgb x][P rgb 1] }
    noise_generator 3
  }
  finish { ambient 1 }
}


Thanks POV-Team!
Michael
--
camera{location<8,20>look_at<6,0,4>}light_source{<8,8>rgb 1}difference{union{
#macro M(D,J)#local R=asc(substr(D,J,1))-32;<div(R,10)*2,mod(R,10)>#end#macro
E(D,B,R)prism{-D,4+D,R#local C=1;#while(C<R+1)M(B,C)#local C=C+1;#end}#end E(
0," (2:FPKAD80* U_dZU"18)sphere{2,2}#macro T(N)cylinder{<9,-N,3><9,4+N,3>3-N}
#end T(0)}T(2)E(1"45LNXUK4"8)pigment{rgb x+y/2}}//(c)2001 MDJohnson(Redbeard)


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From: Redbeard (MDJohnson)
Subject: Re: Granite and noise gen 3 bug?
Date: 14 Oct 2001 12:23:16
Message: <3bc9bbf4$1@news.povray.org>
Forgot to mention:
POV-Ray 3.5b6, PIII 733 160MB and Athlon 700 192MB, both Win98SE

Michael


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From: Warp
Subject: Re: Granite and noise gen 3 bug?
Date: 14 Oct 2001 13:04:53
Message: <3bc9c5b4@news.povray.org>
Somehow I have the feeling that the granite pattern was developed to use
the original noise generator function in such a way that it wouldn't suffer
from clamping (ie. the plateaus). However now that the new noise doesn't
suffer from the over-exaggeration problem, the values are too small for
the granite pattern, which hasn't been fixed for the new noise function.

  On the other hand, I don't know if it would be a good idea to "fix" the
granite pattern because it could then work wrongly with noise_generator 1.

  Perhaps it could be a good idea to make the granite pattern to use
noise_generator 1 by default (you could then change it in the usualy way
if you want it to use another generator).

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -


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