Game/src/PerlinNoise.php

<?php

namespace Ardent\Game;

class PerlinNoise
{

    private array $p;
    private float $seed;
    private int $_default_size = 64;

    public function __construct(?int $seed = null)
    {
        //Initialize the permutation array.
        $this->p = [];
        $permutation = [
            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,
        ];

        //Populate it
        for ($i = 0; $i < 256; $i++) {
            $this->p[256 + $i] = $this->p[$i] = $permutation[$i];
        }

        //And set the seed
        if ($seed === null) {
            $seed = time();
        }

        srand($seed);
        $this->seed = rand(0, 1000000);
    }

    function noise($x, $y, $z, $size = NULL): float|int
    {
        if ($size == NULL) $size = $this->_default_size;

        //Set the initial value and initial size
        $value = 0.0;
        $initialSize = $size;

        //Add finer and finer hues of smoothed noise together
        while ($size >= 1) {

            $value += $this->smoothNoise($x / $size, $y / $size, $z / $size) * $size;
            $size /= 2.0;

        }

        //Return the result over the initial size
        return $value / $initialSize;

    }

    //This function determines what cube the point passed resides in
    //and determines its value.
    function smoothNoise(float $x, float $y, float $z): float
    {
        //Offset each coordinate by the seed value
        $x += $this->seed;
        $y += $this->seed;
        $z += $this->seed;

        $orig_x = $x;
        $orig_y = $y;
        $orig_z = $z;

        $X1 = (int)floor($x) & 255;                  // FIND UNIT CUBE THAT
        $Y1 = (int)floor($y) & 255;                  // CONTAINS POINT.
        $Z1 = (int)floor($z) & 255;
        $x -= floor($x);                                // FIND RELATIVE X,Y,Z
        $y -= floor($y);                                // OF POINT IN CUBE.
        $z -= floor($z);
        $u = $this->fade($x);                                // COMPUTE FADE CURVES
        $v = $this->fade($y);                                // FOR EACH OF X,Y,Z.
        $w = $this->fade($z);

        $A = $this->p[$X1] + $Y1;
        $AA = $this->p[$A] + $Z1;
        $AB = $this->p[$A + 1] + $Z1;      // HASH COORDINATES OF
        $B = $this->p[$X1 + 1] + $Y1;
        $BA = $this->p[$B] + $Z1;
        $BB = $this->p[$B + 1] + $Z1;      // THE 8 CUBE CORNERS,

        //Interpolate between the 8 points determined
        return $this->lerp($w, $this->lerp($v, $this->lerp($u, $this->grad($this->p[$AA], $x, $y, $z),  // AND ADD
            $this->grad($this->p[$BA], $x - 1, $y, $z)), // BLENDED
            $this->lerp($u, $this->grad($this->p[$AB], $x, $y - 1, $z),  // RESULTS
                $this->grad($this->p[$BB], $x - 1, $y - 1, $z))),// FROM  8
            $this->lerp($v, $this->lerp($u, $this->grad($this->p[$AA + 1], $x, $y, $z - 1),  // CORNERS
                $this->grad($this->p[$BA + 1], $x - 1, $y, $z - 1)), // OF CUBE
                $this->lerp($u, $this->grad($this->p[$AB + 1], $x, $y - 1, $z - 1),
                    $this->grad($this->p[$BB + 1], $x - 1, $y - 1, $z - 1))));
    }

    function fade(float $t): float
    {
        return $t * $t * $t * (($t * (($t * 6) - 15)) + 10);
    }

    function lerp(float $t, float $a, float $b): float
    {
        //Make a weighted interpolation between points
        return $a + $t * ($b - $a);
    }

    function grad($hash, float $x, float $y, float $z): float
    {
        $h = $hash & 15;                      // CONVERT LO 4 BITS OF HASH CODE
        $u = $h < 8 ? $x : $y;                 // INTO 12 GRADIENT DIRECTIONS.
        $v = $h < 4 ? $y : ($h == 12 || $h == 14 ? $x : $z);

        return (($h & 1) == 0 ? $u : -$u) + (($h & 2) == 0 ? $v : -$v);
    }

    //This function I've added. It creates one dimension of noise.
    function random1D(float $x, ?int $size = null): float
    {
        if ($size === NULL) {
            $size = $this->_default_size;
        }

        $x += $this->seed;

        $value = 0.0;
        $initialSize = $size;

        while ($size >= 1) {
            $value += $this->smoothNoise($x * 3 / $size, 100 / $size, 100 / $size);
            $size--;
        }

        if ($value < -1) $value = -1;
        if ($value > 1) $value = 1;

        return $value;
    }

    function random2D(float $x, float $y, ?int $size = null, float $multiplier = 1.0): float
    {
        if ($size === NULL) {
            $size = $this->_default_size;
        }

        $x += $this->seed;
        $y += $this->seed;

        $value = 0.0;
        $initialSize = $size;

        while ($size >= 1) {
            $value += $this->smoothNoise($x / $size, $y / $size, 100 / $size);
            $size--;
        }

//        $value /= 2.0;

        return $this->sigmoid($value * $multiplier);
    }

    private function sigmoid(float $t): float
    {
        return 2.0 / (1.0 + exp(-$t)) - 1.0;
    }
}