phaser4-rex-plugins/plugins/utils/math/noise/Simplex1.js

Plugins of phaser4

//https://github.com/SRombauts/SimplexNoise/blob/master/src/SimplexNoise.cpp    
const 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];
// global

class Noise {
    constructor() {
        this.perm = new Uint8Array(256);
    }

    setSeed(seed) {
        if (seed > 0 && seed < 1) {
            // Scale the seed out
            seed *= 65536;
        }

        seed = Math.floor(seed);
        if (seed < 256) {
            seed |= seed << 8;
        }

        var v;
        for (var i = 0; i < 256; i++) {
            if (i & 1) {
                v = p[i] ^ (seed & 255);
            }
            else {
                v = p[i] ^ ((seed >> 8) & 255);
            }

            this.perm[i] = v;
        }
    }

    hash(i) {
        return this.perm[i & 255];
    }

    simplex1(x) {
        var n0, n1;   // Noise contributions from the two "corners"

        // No need to skew the input space in 1D

        // Corners coordinates (nearest integer values):
        var i0 = Math.floor(x);
        var i1 = i0 + 1.0;
        // Distances to corners (between 0 and 1):
        var x0 = x - i0;
        var x1 = x0 - 1.0;

        // Calculate the contribution from the first corner
        var t0 = 1.0 - x0 * x0;
        //  if(t0 < 0.0f) t0 = 0.0f; // not possible
        t0 *= t0;
        n0 = t0 * t0 * gradP(this.hash(i0), x0);  // TODO

        // Calculate the contribution from the second corner
        var t1 = 1.0 - x1 * x1;
        //  if(t1 < 0.0f) t1 = 0.0f; // not possible
        t1 *= t1;
        n1 = t1 * t1 * gradP(this.hash(i1), x1); // TODO

        // The maximum value of this noise is 8*(3/4)^4 = 2.53125
        // A factor of 0.395 scales to fit exactly within [-1,1]
        // 0.9395123193338055 ~ -0.99984375
        return 0.395 * (n0 + n1);
    };
}

var gradP = function (hash, x) {
    var h = hash & 0x0F;        // Convert low 4 bits of hash code
    var grad = 1 + (h & 7);    // Gradient value 1.0, 2.0, ..., 8.0
    if ((h & 8) !== 0) grad = -grad; // Set a random sign for the gradient
    //  float grad = gradients1D[h];    // NOTE : Test of Gradient look-up table instead of the above
    return (grad * x);              // Multiply the gradient with the distance
};

export default Noise;