Simplex Noise generator

SimplexNoise.cs

/// <summary>
/// from http://stephencarmody.wikispaces.com/Simplex+Noise
/// 
/// blind conversion to C#... let's see what blows up.
/// 
/// NOT THREADSAFE
/// </summary>
public static class SimplexNoise
{
    private const float onethird = 0.333333333f;
    private const float onesixth = 0.166666667f;
    private static int[] T = { 0x15, 0x38, 0x32, 0x2c, 0x0d, 0x13, 0x07, 0x2a };

    private static float u, v, w, s;
    private static int i, j, k;
    private static int[] A = { 0, 0, 0 };

    public static float[,] Noise(int width, int height, float x, float y, float z, bool normalize = false)
    {
        Random rand = new Random();
        float[,] map = new float[width, height];
        float zOffset = rand.Next() * 0.001f;

        float min = 100;
        float max = -100;

        //sampling the noise
        for (int xx = 0; xx < width; xx++)
        {
            for (int yy = 0; yy < height; yy++)
            {
                map[xx, yy] = Noise(xx * x, yy * y, z);
                if (map[xx, yy] > max)
                    max = map[xx, yy];
                if (map[xx, yy] < min)
                    min = map[xx, yy];
            }
        }

        if (normalize)
        {
            //normalizing
            for (int xx = 0; xx < width; xx++)
            {
                for (int yy = 0; yy < height; yy++)
                {
                    map[xx, yy] = (map[xx, yy] - min) / (max - min);
                }
            }
        }

        return map;
    }

    public static float Noise(float x, float y, float z)
    {

        // Skew input space to relative coordinate in simplex cell
        s = (x + y + z) * onethird;
        i = fastfloor(x + s);
        j = fastfloor(y + s);
        k = fastfloor(z + s);

        // Unskew cell origin back to (x, y , z) space
        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;

        // For 3D case, the simplex shape is a slightly irregular tetrahedron.
        // Determine which simplex we're in
        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 K(hi) + K(3 - hi - lo) + K(lo) + K(0);
    }

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

    private static float K(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 b = h & 3;
        float p = b == 1 ? x : b == 2 ? y : z;
        float q = b == 1 ? y : b == 2 ? z : x;
        float r = b == 1 ? z : b == 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 + (b == 0 ? q + r : b2 == 0 ? q : r));
    }

    private static 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);
    }

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

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

}