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Forked from jstanden/gist:1489447
Created March 23, 2019 21:19
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Revisions

  1. @jstanden jstanden revised this gist Sep 6, 2016. No changes.
  2. @jstanden jstanden created this gist Dec 17, 2011.
    129 changes: 129 additions & 0 deletions gistfile1.cs
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,129 @@
    using UnityEngine;
    using System.Collections;

    public class SimplexNoiseGenerator {
    private int[] A = new int[3];
    private float s, u, v, w;
    private int i, j, k;
    private float onethird = 0.333333333f;
    private float onesixth = 0.166666667f;
    private int[] T;

    public SimplexNoiseGenerator() {
    if (T == null) {
    System.Random rand = new System.Random();
    T = new int[8];
    for (int q = 0; q < 8; q++)
    T[q] = rand.Next();
    }
    }

    public SimplexNoiseGenerator(string seed) {
    T = new int[8];
    string[] seed_parts = seed.Split(new char[] {' '});

    for(int q = 0; q < 8; q++) {
    int b;
    try {
    b = int.Parse(seed_parts[q]);
    } catch {
    b = 0x0;
    }
    T[q] = b;
    }
    }

    public SimplexNoiseGenerator(int[] seed) { // {0x16, 0x38, 0x32, 0x2c, 0x0d, 0x13, 0x07, 0x2a}
    T = seed;
    }

    public string GetSeed() {
    string seed = "";

    for(int q=0; q < 8; q++) {
    seed += T[q].ToString();
    if(q < 7)
    seed += " ";
    }

    return seed;
    }

    public float coherentNoise(float x, float y, float z, int octaves=1, int multiplier = 25, float amplitude = 0.5f, float lacunarity = 2, float persistence = 0.9f) {
    Vector3 v3 = new Vector3(x,y,z)/multiplier;
    float val = 0;
    for (int n = 0; n < octaves; n++) {
    val += noise(v3.x,v3.y,v3.z) * amplitude;
    v3 *= lacunarity;
    amplitude *= persistence;
    }
    return val;
    }

    public int getDensity(Vector3 loc) {
    float val = coherentNoise(loc.x, loc.y, loc.z);
    return (int)Mathf.Lerp(0,255,val);
    }

    // Simplex Noise Generator
    public float noise(float x, float y, float z) {
    s = (x + y + z) * onethird;
    i = fastfloor(x + s);
    j = fastfloor(y + s);
    k = fastfloor(z + s);

    s = (i + j + k) * onesixth;
    u = x - i + s;
    v = y - j + s;
    w = z - k + s;

    A[0] = 0; A[1] = 0; A[2] = 0;

    int hi = u >= w ? u >= v ? 0 : 1 : v >= w ? 1 : 2;
    int lo = u < w ? u < v ? 0 : 1 : v < w ? 1 : 2;

    return kay(hi) + kay(3 - hi - lo) + kay(lo) + kay(0);
    }

    float kay(int a) {
    s = (A[0] + A[1] + A[2]) * onesixth;
    float x = u - A[0] + s;
    float y = v - A[1] + s;
    float z = w - A[2] + s;
    float t = 0.6f - x * x - y * y - z * z;
    int h = shuffle(i + A[0], j + A[1], k + A[2]);
    A[a]++;
    if (t < 0) return 0;
    int b5 = h >> 5 & 1;
    int b4 = h >> 4 & 1;
    int b3 = h >> 3 & 1;
    int b2 = h >> 2 & 1;
    int b1 = h & 3;

    float p = b1 == 1 ? x : b1 == 2 ? y : z;
    float q = b1 == 1 ? y : b1 == 2 ? z : x;
    float r = b1 == 1 ? z : b1 == 2 ? x : y;

    p = b5 == b3 ? -p : p;
    q = b5 == b4 ? -q : q;
    r = b5 != (b4 ^ b3) ? -r : r;
    t *= t;
    return 8 * t * t * (p + (b1 == 0 ? q + r : b2 == 0 ? q : r));
    }

    int shuffle(int i, int j, int k) {
    return b(i, j, k, 0) + b(j, k, i, 1) + b(k, i, j, 2) + b(i, j, k, 3) + b(j, k, i, 4) + b(k, i, j, 5) + b(i, j, k, 6) + b(j, k, i, 7);
    }

    int b(int i, int j, int k, int B) {
    return T[b(i, B) << 2 | b(j, B) << 1 | b(k, B)];
    }

    int b(int N, int B) {
    return N >> B & 1;
    }

    int fastfloor(float n) {
    return n > 0 ? (int)n : (int)n - 1;
    }
    }