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Simplex Noise with Easier Variable Names

a guest May 22nd, 2013 120 Never
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  1. // Wip of my renaming of the variable names in the simplex noise program into something more intelligible
  2.  
  3. using UnityEngine;
  4. using System.Collections;
  5.  
  6. public class Noise : MonoBehaviour {
  7.        
  8.         float persistance, frequency, amplitude;
  9.         int octaves, randomseed;
  10.        
  11.         public Noise() {
  12.                 persistance = 0f;
  13.                 frequency = 0f;
  14.                 amplitude = 0f;
  15.                 octaves = 0;
  16.                 randomseed = 0;
  17.         }
  18.        
  19.         public Noise(float _persistance, float _frequency, float _amplitude, int _octaves, int _randomseed) {
  20.                 persistance = _persistance;
  21.                 frequency = _frequency;
  22.                 amplitude = _amplitude;
  23.                 octaves = _octaves;
  24.                 randomseed = 2 + _randomseed * randomseed;
  25.         }
  26.        
  27.         public void Set(float _persistance, float _frequency, float _amplitude, int _octaves, int _randomseed) {
  28.                 persistance = _persistance;
  29.                 frequency = _frequency;
  30.                 amplitude = _amplitude;
  31.                 octaves = _octaves;
  32.                 randomseed = 2 + _randomseed * randomseed;
  33.         }
  34.        
  35. //      public float GetHeight(float x, float y) {
  36. //              //
  37. //      }
  38. //     
  39. //      public float Total(float i, float j) {
  40. //              //Properties of one octave (changing each loop)
  41. //              float t = 0.0f;
  42. //              float _amplitude = 1f;
  43. //              double freq = frequency;
  44. //             
  45. //              for(int k = 0; k < octaves; k++) {
  46. //                      t += (j + freq + randomseed     );
  47. //              }
  48. //      }
  49. //                             
  50. //      public float GetValue(float x, float y) {
  51. //                     
  52. //              int Xint = (int)x;
  53. //              int Yint = (int)y;
  54. //              float Xfrac = x - Xint;
  55. //              float Yfrac = y - Yint;
  56. //             
  57. //              // noise values
  58. //             
  59. //      }
  60.        
  61.        
  62.         public static float Generate(float x, float y) {
  63.                
  64.                 // Pre-computed skew factors
  65.                 const float skew = 0.366025403f; // skew = 0.5*(sqrt(3.0)-1.0)
  66.         const float unskew = 0.211324865f; // unskew = (3.0-Math.sqrt(3.0))/6.0
  67.                
  68.                 // Noise Contribution from the three corners (N dimensions)
  69.                 float noise0, noise1, noise2;
  70.                
  71.                 // Skew the input space along the main diagonal
  72.             float skewFactor = (x + y) * skew; // Hairy factor for 2D
  73.         int simplexCell_i = FastFloor(x + skewFactor);
  74.         int simplexCell_j = FastFloor(y + skewFactor);
  75.                
  76.                 // Align hypercube to grid by unskewing the cell origin back to (x, y) space
  77.                 float unskewFactor = (float)(simplexCell_i + simplexCell_j) * unskew;
  78.         float unskewed_x = simplexCell_i - unskewFactor;
  79.         float unskewed_y = simplexCell_j - unskewFactor;
  80.                
  81.                 // Get distances from the cell origin
  82.         float x_distance0 = x - unskewed_x;
  83.         float y_distance0 = y - unskewed_y;
  84.  
  85.         // Determine which simplex we are in within the equilateral triangle.
  86.                
  87.         int i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords
  88.        
  89.                 // lower triangle, XY order: (0,0)->(1,0)->(1,1)
  90.                 if(x_distance0 > y_distance0) {
  91.                         i1 = 1;
  92.                         j1 = 0;
  93.                 }
  94.                 // upper triangle, YX order: (0,0)->(0,1)->(1,1)
  95.                 else {
  96.                         i1 = 0;
  97.                         j1 = 1;
  98.                 }    
  99.  
  100.         // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
  101.         // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
  102.         // c = (3-sqrt(3))/6
  103.  
  104.         float x1 = x_distance0 - i1 + unskew; // Offsets for middle corner in (x,y) unskewed coords
  105.         float y1 = y_distance0 - j1 + unskew;
  106.         float x2 = x_distance0 - 1.0f + 2.0f * unskew; // Offsets for last corner in (x,y) unskewed coords
  107.         float y2 = y_distance0 - 1.0f + 2.0f * unskew;
  108.  
  109.         // Wrap the integer indices at 256, to avoid indexing perm[] out of bounds
  110.         int ii = simplexCell_i % 256;
  111.         int jj = simplexCell_j % 256;
  112.  
  113.         // Calculate the contribution from the three corners
  114.                
  115.                 // Corner one
  116.         float t0 = 0.5f - x_distance0*x_distance0-y_distance0*y_distance0;
  117.         if(t0 < 0.0f) noise0 = 0.0f;
  118.         else {
  119.             t0 *= t0;
  120.             noise0 = t0 * t0 * grad(perm[ii+perm[jj]], x_distance0, y_distance0);
  121.         }
  122.  
  123.                 // Corner two
  124.         float t1 = 0.5f - x1*x1-y1*y1;
  125.         if(t1 < 0.0f) noise1 = 0.0f;
  126.         else {
  127.             t1 *= t1;
  128.             noise1 = t1 * t1 * grad(perm[ii+i1+perm[jj+j1]], x1, y1);
  129.         }
  130.                
  131.                 // Corner three
  132.         float t2 = 0.5f - x2*x2-y2*y2;
  133.         if(t2 < 0.0f) noise2 = 0.0f;
  134.         else {
  135.             t2 *= t2;
  136.             noise2 = t2 * t2 * grad(perm[ii+1+perm[jj+1]], x2, y2);
  137.         }
  138.  
  139.         // Add contributions from each corner to get the final noise value.
  140.         // The result is scaled to return values in the interval [-1,1].
  141.         return 40.0f * (noise0 + noise1 + noise2); // TODO: The scale factor is preliminary!= (x + y) * skew;
  142.         }
  143.        
  144.         private static byte[] perm = new byte[512] { 151,160,137,91,90,15,
  145.               131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
  146.               190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
  147.               88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
  148.               77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
  149.               102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
  150.               135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
  151.               5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
  152.               223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
  153.               129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
  154.               251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
  155.               49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
  156.               138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180,
  157.               151,160,137,91,90,15,
  158.               131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
  159.               190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
  160.               88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
  161.               77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
  162.               102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
  163.               135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
  164.               5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
  165.               223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
  166.               129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
  167.               251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
  168.               49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
  169.               138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
  170.             };
  171.        
  172.         private static int FastFloor(float x)
  173.     {
  174.             return (x > 0) ? ((int)x) : (((int)x) - 1);
  175.         }
  176.        
  177.         private static float grad( int hash, float x, float y )
  178.     {
  179.                 int h = hash & 7;      // Convert low 3 bits of hash code
  180.                 float u = h<4 ? x : y;  // into 8 simple gradient directions,
  181.                 float v = h<4 ? y : x;  // and compute the dot product with (x,y).
  182.                
  183.                 return ((h&1) != 0 ? -u : u) + ((h&2) != 0 ? -2.0f*v : 2.0f*v);
  184.     }
  185. }
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