POV-Ray : Newsgroups : povray.text.scene-files : Help needed with Noise Function! Server Time
1 Nov 2024 07:25:17 EDT (-0400)
  Help needed with Noise Function! (Message 1 to 2 of 2)  
From: Lonnie Ezell
Subject: Help needed with Noise Function!
Date: 9 Jan 2001 00:22:05
Message: <3a5a9ffd@news.povray.org>
I originally posted this in povray.advanced-users, and they suggested I post
it here.

I have what I believe is a working 2D Perlin Noise macro. Eventually I hope
to have 1D, 2D, 3D & 4D macros. After solving a number of small bugs in the
script when I try to use it, POV crashes on me. I've tried reinstalling and
the same results.

Could someone look it over for me to see if you can spot what's wrong.

Thanks,
Lonnie


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Attachments:
Download '8DInterp.inc.txt' (3 KB) Download '8D_noise.inc.txt' (6 KB) Download 'noise.pov.txt' (1 KB)

From: Tor Olav Kristensen
Subject: Re: Help needed with Noise Function!
Date: 18 Jan 2001 20:48:43
Message: <3A679CD3.CB5F8C27@online.no>
Lonnie Ezell wrote:
> 
> I originally posted this in povray.advanced-users, and they suggested I post
> it here.
> 
> I have what I believe is a working 2D Perlin Noise macro. Eventually I hope
> to have 1D, 2D, 3D & 4D macros. After solving a number of small bugs in the
> script when I try to use it, POV crashes on me. I've tried reinstalling and
> the same results.
> 
> Could someone look it over for me to see if you can spot what's wrong.

See code below and my comments in povray.advanced-users

-- 
Best regards,

Tor Olav

mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html


// ===== 1 ======= 2 ======= 3 ======= 4 ======= 5 ======= 6 ======= 7

#version 3.1;

#include "colors.inc"

// ===== 1 ======= 2 ======= 3 ======= 4 ======= 5 ======= 6 ======= 7

#macro LinearInterpolate(A, B, M_x)

  (A*(1 - M_x) + B*M_x)

#end // macro LinearInterpolate



#macro CosineInterpolate(A, B, M_x)

  LinearInterpolate(A, B, (1 - cos(M_x*pi))/2)

#end // macro CosineInterpolate



#macro CubicInterpolate(V0, V1, V2, V3, M_x)

  #local P = V3 - V2 - V0 + V1;
  #local Q = V0 - V1 - P;
  #local R = V2 - V0;
  #local S = V1; 
  
  (P*pow(M_x, 3) + Q*pow(M_x, 2) + R*M_x + S)

#end // macro CubicInterpolate
                 

	                                      
#macro NOISE_Init(N, SeedArray)

  #local NrOfOctaves = dimension_size(SeedArray, 1);
  #declare SeedArray[0] = seed(N);
  #local I = 1;
  #while (I < NrOfOctaves)
    #declare SeedArray[I] = seed(N*I*pow(I + 1, 2)/(I + 2));
    #local I = I + 1;
  #end

#end // macro NOISE_Init



// This macro should be rewritten
#macro NOISE_Rand_2D(M_x, M_y, Octave, SeedArray)

  (rand(SeedArray[Octave])*M_x + rand(SeedArray[Octave])*M_y)/2

#end // macro NOISE_Rand_2D


	                                      
#macro NOISE_Smooth_2D(M_x, M_y, Octave, SeedArray)

  #local Corners =
    NOISE_Rand_2D(M_x - 1, M_y - 1, Octave, SeedArray) +
    NOISE_Rand_2D(M_x + 1, M_y - 1, Octave, SeedArray) +
    NOISE_Rand_2D(M_x - 1, M_y + 1, Octave, SeedArray) +
    NOISE_Rand_2D(M_x + 1, M_y + 1, Octave, SeedArray);
  #local Sides =
    NOISE_Rand_2D(M_x - 1, M_y,     Octave, SeedArray) + 
    NOISE_Rand_2D(M_x + 1, M_y,     Octave, SeedArray) +
    NOISE_Rand_2D(M_x,     M_y - 1, Octave, SeedArray) +
    NOISE_Rand_2D(M_x,     M_y + 1, Octave, SeedArray);
  #local Center =
    NOISE_Rand_2D(M_x,     M_y,     Octave, SeedArray);
                              
  (Corners/16 + Sides/8 + Center/4)

#end // macro NOISE_Smooth_2D



#macro NOISE_Interp_2D(M_x, M_y, Octave, SeedArray)

  #local Int_x  = int(M_x);
  #local Frac_x = M_x - Int_x;
  #local Int_y  = int(M_y);
  #local Frac_y = M_y - Int_y;
   
  #local V1 = NOISE_Smooth_2D(Int_x,     Int_y,     Octave, SeedArray);
  #local V2 = NOISE_Smooth_2D(Int_x + 1, Int_y,     Octave, SeedArray);
  #local V3 = NOISE_Smooth_2D(Int_x,     Int_y + 1, Octave, SeedArray);
  #local V4 = NOISE_Smooth_2D(Int_x + 1, Int_y + 1, Octave, SeedArray);
   
  #local I1 = CosineInterpolate(V1, V2, Frac_x);
  #local I2 = CosineInterpolate(V3, V4, Frac_x);
   
  CosineInterpolate(I1, I2, Frac_y)

#end // macro NOISE_Interp_2D



#macro NOISE_Noise_2D(M_x, M_y, Persist, SeedArray)

  #local NrOfOctaves = dimension_size(SeedArray, 1);
  #local Total = 0;
  #local I = 0;
  #while(I < NrOfOctaves)
    #local Freq = pow(2, I);
    #local Ampl = pow(Persist, I);  
    #local Total = 
      Total + Ampl*NOISE_Interp_2D(M_x*Freq, M_y*Freq, I, SeedArray);
    #local I = I + 1;
  #end    
   
  Total   

#end // macro NOISE_Noise_2D

// ===== 1 ======= 2 ======= 3 ======= 4 ======= 5 ======= 6 ======= 7

#declare NOISE_Octaves = 2;
#declare NOISE_Persistence = 0.5;
#declare AnyNumber = 12345;

// ===== 1 ======= 2 ======= 3 ======= 4 ======= 5 ======= 6 ======= 7

#declare NOISE_SeedArray = array[NOISE_Octaves]

NOISE_Init(AnyNumber, NOISE_SeedArray)

#declare Xnr = 10;
#declare Znr = 10;

union {
  #declare I = 0;
  #while (I < Xnr)
    #declare J = 0;
    #while (J < Znr)
      #declare Perlin = 
        NOISE_Noise_2D(I, J, NOISE_Persistence, NOISE_SeedArray);
      box {
        -<1, 1, 1>/2,
         <1, 1, 1>/2
        pigment { color <0, Perlin, 0> }
        translate <I, 0, J>
      }
      #declare J = J + 1;
    #end // while         
    #declare I = I + 1;
  #end // while
  translate (<1, 0, 1> - <Xnr, 0, Znr>)/2
}


light_source {
  <0, 60, 0>
  color White
}                             


camera {
  location <0, 15, 0>
  look_at <0, 0, 0>
}                     

// ===== 1 ======= 2 ======= 3 ======= 4 ======= 5 ======= 6 ======= 7


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