package org.sunflow.math;

/**
 * Noise function from Ken Perlin. Additional routines are provided to emulate
 * standard Renderman calls. This code was adapted mainly from the mrclasses
 * package by Gonzalo Garramuno (http://sourceforge.net/projects/mrclasses/).
 * 
 * @link http://mrl.nyu.edu/~perlin/noise/
 */
public final class PerlinScalar {
    private static final float[] G1 = { -1, 1 };
    private static final float[][] G2 = { { 1, 0 }, { -1, 0 }, { 0, 1 },
            { 0, -1 } };
    private static final float[][] G3 = { { 1, 1, 0 }, { -1, 1, 0 },
            { 1, -1, 0 }, { -1, -1, 0 }, { 1, 0, 1 }, { -1, 0, 1 },
            { 1, 0, -1 }, { -1, 0, -1 }, { 0, 1, 1 }, { 0, -1, 1 },
            { 0, 1, -1 }, { 0, -1, -1 }, { 1, 1, 0 }, { -1, 1, 0 },
            { 0, -1, 1 }, { 0, -1, -1 } };
    private static final float[][] G4 = { { -1, -1, -1, 0 }, { -1, -1, 1, 0 },
            { -1, 1, -1, 0 }, { -1, 1, 1, 0 }, { 1, -1, -1, 0 },
            { 1, -1, 1, 0 }, { 1, 1, -1, 0 }, { 1, 1, 1, 0 },
            { -1, -1, 0, -1 }, { -1, 1, 0, -1 }, { 1, -1, 0, -1 },
            { 1, 1, 0, -1 }, { -1, -1, 0, 1 }, { -1, 1, 0, 1 },
            { 1, -1, 0, 1 }, { 1, 1, 0, 1 }, { -1, 0, -1, -1 },
            { 1, 0, -1, -1 }, { -1, 0, -1, 1 }, { 1, 0, -1, 1 },
            { -1, 0, 1, -1 }, { 1, 0, 1, -1 }, { -1, 0, 1, 1 }, { 1, 0, 1, 1 },
            { 0, -1, -1, -1 }, { 0, -1, -1, 1 }, { 0, -1, 1, -1 },
            { 0, -1, 1, 1 }, { 0, 1, -1, -1 }, { 0, 1, -1, 1 },
            { 0, 1, 1, -1 }, { 0, 1, 1, 1 } };
    private static final int[] p = { 151, 160, 137, 91, 90, 15, 131, 13, 201,
            95, 96, 53, 194, 233, 7, 225, 140, 36, 103, 30, 69, 142, 8, 99, 37,
            240, 21, 10, 23, 190, 6, 148, 247, 120, 234, 75, 0, 26, 197, 62,
            94, 252, 219, 203, 117, 35, 11, 32, 57, 177, 33, 88, 237, 149, 56,
            87, 174, 20, 125, 136, 171, 168, 68, 175, 74, 165, 71, 134, 139,
            48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122, 60, 211, 133,
            230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54, 65, 25,
            63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169, 200,
            196, 135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3,
            64, 52, 217, 226, 250, 124, 123, 5, 202, 38, 147, 118, 126, 255,
            82, 85, 212, 207, 206, 59, 227, 47, 16, 58, 17, 182, 189, 28, 42,
            223, 183, 170, 213, 119, 248, 152, 2, 44, 154, 163, 70, 221, 153,
            101, 155, 167, 43, 172, 9, 129, 22, 39, 253, 19, 98, 108, 110, 79,
            113, 224, 232, 178, 185, 112, 104, 218, 246, 97, 228, 251, 34, 242,
            193, 238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235, 249,
            14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157, 184, 84, 204,
            176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93, 222,
            114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180,
            151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7,
            225, 140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6,
            148, 247, 120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35,
            11, 32, 57, 177, 33, 88, 237, 149, 56, 87, 174, 20, 125, 136, 171,
            168, 68, 175, 74, 165, 71, 134, 139, 48, 27, 166, 77, 146, 158,
            231, 83, 111, 229, 122, 60, 211, 133, 230, 220, 105, 92, 41, 55,
            46, 245, 40, 244, 102, 143, 54, 65, 25, 63, 161, 1, 216, 80, 73,
            209, 76, 132, 187, 208, 89, 18, 169, 200, 196, 135, 130, 116, 188,
            159, 86, 164, 100, 109, 198, 173, 186, 3, 64, 52, 217, 226, 250,
            124, 123, 5, 202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206,
            59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213, 119,
            248, 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9,
            129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185,
            112, 104, 218, 246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12,
            191, 179, 162, 241, 81, 51, 145, 235, 249, 14, 239, 107, 49, 192,
            214, 31, 181, 199, 106, 157, 184, 84, 204, 176, 115, 121, 50, 45,
            127, 4, 150, 254, 138, 236, 205, 93, 222, 114, 67, 29, 24, 72, 243,
            141, 128, 195, 78, 66, 215, 61, 156, 180 };

    public static final float snoise(float x) {
        int xf = (int) Math.floor(x);
        int X = xf & 255;
        x -= xf;
        float u = fade(x);
        int A = p[X], B = p[X + 1];
        return lerp(u, grad(p[A], x), grad(p[B], x - 1));
    }

    public static final float snoise(float x, float y) {
        int xf = (int) Math.floor(x);
        int yf = (int) Math.floor(y);
        int X = xf & 255;
        int Y = yf & 255;
        x -= xf;
        y -= yf;
        float u = fade(x);
        float v = fade(y);
        int A = p[X] + Y, B = p[X + 1] + Y;
        return lerp(v, lerp(u, grad(p[A], x, y), grad(p[B], x - 1, y)), lerp(u, grad(p[A + 1], x, y - 1), grad(p[B + 1], x - 1, y - 1)));
    }

    public static final float snoise(float x, float y, float z) {
        int xf = (int) Math.floor(x);
        int yf = (int) Math.floor(y);
        int zf = (int) Math.floor(z);
        int X = xf & 255;
        int Y = yf & 255;
        int Z = zf & 255;
        x -= xf;
        y -= yf;
        z -= zf;
        float u = fade(x);
        float v = fade(y);
        float w = fade(z);
        int A = p[X] + Y, AA = p[A] + Z, AB = p[A + 1] + Z, B = p[X + 1] + Y, BA = p[B] + Z, BB = p[B + 1] + Z;
        return lerp(w, lerp(v, lerp(u, grad(p[AA], x, y, z), grad(p[BA], x - 1, y, z)), lerp(u, grad(p[AB], x, y - 1, z), grad(p[BB], x - 1, y - 1, z))), lerp(v, lerp(u, grad(p[AA + 1], x, y, z - 1), grad(p[BA + 1], x - 1, y, z - 1)), lerp(u, grad(p[AB + 1], x, y - 1, z - 1), grad(p[BB + 1], x - 1, y - 1, z - 1))));
    }

    public static final float snoise(float x, float y, float z, float w) {
        int xf = (int) Math.floor(x);
        int yf = (int) Math.floor(y);
        int zf = (int) Math.floor(z);
        int wf = (int) Math.floor(w);
        int X = xf & 255;
        int Y = yf & 255;
        int Z = zf & 255;
        int W = wf & 255;
        x -= xf;
        y -= yf;
        z -= zf;
        w -= wf;
        float u = fade(x);
        float v = fade(y);
        float t = fade(z);
        float s = fade(w);
        int A = p[X] + Y, AA = p[A] + Z, AB = p[A + 1] + Z, B = p[X + 1] + Y, BA = p[B] + Z, BB = p[B + 1] + Z, AAA = p[AA] + W, AAB = p[AA + 1] + W, ABA = p[AB] + W, ABB = p[AB + 1] + W, BAA = p[BA] + W, BAB = p[BA + 1] + W, BBA = p[BB] + W, BBB = p[BB + 1] + W;
        return lerp(s, lerp(t, lerp(v, lerp(u, grad(p[AAA], x, y, z, w), grad(p[BAA], x - 1, y, z, w)), lerp(u, grad(p[ABA], x, y - 1, z, w), grad(p[BBA], x - 1, y - 1, z, w))), lerp(v, lerp(u, grad(p[AAB], x, y, z - 1, w), grad(p[BAB], x - 1, y, z - 1, w)), lerp(u, grad(p[ABB], x, y - 1, z - 1, w), grad(p[BBB], x - 1, y - 1, z - 1, w)))), lerp(t, lerp(v, lerp(u, grad(p[AAA + 1], x, y, z, w - 1), grad(p[BAA + 1], x - 1, y, z, w - 1)), lerp(u, grad(p[ABA + 1], x, y - 1, z, w - 1), grad(p[BBA + 1], x - 1, y - 1, z, w - 1))), lerp(v, lerp(u, grad(p[AAB + 1], x, y, z - 1, w - 1), grad(p[BAB + 1], x - 1, y, z - 1, w - 1)), lerp(u, grad(p[ABB + 1], x, y - 1, z - 1, w - 1), grad(p[BBB + 1], x - 1, y - 1, z - 1, w - 1)))));
    }

    public static final float snoise(Point2 p) {
        return snoise(p.x, p.y);
    }

    public static final float snoise(Point3 p) {
        return snoise(p.x, p.y, p.z);
    }

    public static final float snoise(Point3 p, float t) {
        return snoise(p.x, p.y, p.z, t);
    }

    public static final float noise(float x) {
        return 0.5f + 0.5f * snoise(x);
    }

    public static final float noise(float x, float y) {
        return 0.5f + 0.5f * snoise(x, y);
    }

    public static final float noise(float x, float y, float z) {
        return 0.5f + 0.5f * snoise(x, y, z);
    }

    public static final float noise(float x, float y, float z, float t) {
        return 0.5f + 0.5f * snoise(x, y, z, t);
    }

    public static final float noise(Point2 p) {
        return 0.5f + 0.5f * snoise(p.x, p.y);
    }

    public static final float noise(Point3 p) {
        return 0.5f + 0.5f * snoise(p.x, p.y, p.z);
    }

    public static final float noise(Point3 p, float t) {
        return 0.5f + 0.5f * snoise(p.x, p.y, p.z, t);
    }