Makelangelo-software

package com.marginallyclever.convenience.noise;

import com.marginallyclever.convenience.helpers.MathHelper;

/**
 * JAVA REFERENCE IMPLEMENTATION OF IMPROVED NOISE - COPYRIGHT 2002 KEN PERLIN.
 * @author ken perlin
 * @since 2002
 */
public class PerlinNoise implements Noise {
    final int [] p = new int[512];
    final int [] 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
    };

    public PerlinNoise() {
        for (int i=0; i < 256 ; i++) {
            p[256+i] = p[i] = permutation[i];
        }
    }

    /**
     * 1D Perlin noise.
     * @param x
     * @return value from -1 to 1.
     */
    @Override
    public double noise(double x) {
        return noise(x,0,0);
    }

    /**
     * 2D Perlin noise.
     * @param x
     * @param y
     * @return value from -1 to 1.
     */
    @Override
    public double noise(double x, double y) {
        return noise(x,y,0);
    }

    /**
     * 3D Perlin noise.
     * @param x
     * @param y
     * @param z
     * @return value from -1 to 1.
     */
    @Override
    public double noise(double x, double y, double z) {
        int X = (int)Math.floor(x) & 255,  // FIND UNIT CUBE THAT CONTAINS POINT.
                Y = (int)Math.floor(y) & 255,
                Z = (int)Math.floor(z) & 255;
        x -= Math.floor(x);  // FIND RELATIVE X,Y,Z OF POINT IN CUBE.
        y -= Math.floor(y);
        z -= Math.floor(z);
        double u = fade(x),  // COMPUTE FADE CURVES FOR EACH OF X,Y,Z.
               v = fade(y),
               w = fade(z);
        // HASH COORDINATES OF THE 8 CUBE CORNERS,
        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;

        // AND ADD BLENDED RESULTS FROM  8 CORNERS OF CUBE
        return MathHelper.lerp(w,
                MathHelper.lerp(v,
                        MathHelper.lerp(u, grad(p[AA  ], x  , y  , z   ),
                                           grad(p[BA  ], x-1, y  , z   )),
                        MathHelper.lerp(u, grad(p[AB  ], x  , y-1, z   ),
                                           grad(p[BB  ], x-1, y-1, z   ))),
                MathHelper.lerp(v,
                        MathHelper.lerp(u, grad(p[AA+1], x  , y  , z-1 ),
                                           grad(p[BA+1], x-1, y  , z-1 )),
                        MathHelper.lerp(u, grad(p[AB+1], x  , y-1, z-1 ),
                                           grad(p[BB+1], x-1, y-1, z-1 ))));
    }

    private double fade(double t) {
        return t * t * t * (t * (t * 6 - 15) + 10);
    }

    private double grad(int hash, double x, double y, double z) {
        int h = hash & 15;  // CONVERT LO 4 BITS OF HASH CODE INTO 12 GRADIENT DIRECTIONS.
        double u = h<8 ? x : y,
               v = h<4 ? y : h==12||h==14 ? x : z;
        return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
    }

    @Override
    public void setSeed(int seed) {
        // not used
    }
}