New ambient mode

[kaka/cakelight.git] / src / kaka / cakelight / util / SimplexNoise3D.java

package kaka.cakelight.util;

import java.util.Random;

import static java.lang.Math.*;

public class SimplexNoise3D {
    private final byte[] ptab = new byte[256];
    private final double[][] gtab = {
            { 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},
    };

    public SimplexNoise3D(Random rnd) {
        for(int i = 0; i < 256; i++)
            ptab[i] = (byte)i;
        for(int i = 0; i < 256; i++) {
            int r = rnd.nextInt(256);
            byte t = ptab[i]; ptab[i] = ptab[r]; ptab[r] = t;
        }
    }

    public SimplexNoise3D(long seed) {
        this(new Random(seed));
    }

    public SimplexNoise3D() {
        this(new Random());
    }

    public double get(double r, double x, double y, double z) {
        x /= r; y /= r; z /= r;

        double i, j, k;
        {
            double s = (x + y + z) / 3;
            i = floor(x + s);
            j = floor(y + s);
            k = floor(z + s);
        }

        double dx, dy, dz;
        {
            double s = (i + j + k) / 6;
            dx = x - (i - s);
            dy = y - (j - s);
            dz = z - (k - s);
        }

        int i1, j1, k1, i2, j2, k2;
        if((dx >= dy) && (dy >= dz)) {
            i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 1; k2 = 0;
        } else if((dx >= dz) && (dz >= dy)) {
            i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 0; k2 = 1;
        } else if((dz >= dx) && (dx >= dy)) {
            i1 = 0; j1 = 0; k1 = 1; i2 = 1; j2 = 0; k2 = 1;
        } else if((dz >= dy) && (dy >= dx)) {
            i1 = 0; j1 = 0; k1 = 1; i2 = 0; j2 = 1; k2 = 1;
        } else if((dy >= dz) && (dz >= dx)) {
            i1 = 0; j1 = 1; k1 = 0; i2 = 0; j2 = 1; k2 = 1;
        } else /* if((dy >= dx) && (dx >= dz)) */ {
            i1 = 0; j1 = 1; k1 = 0; i2 = 1; j2 = 1; k2 = 0;
        }

        double x1 = dx - i1 + (1.0 / 6.0), y1 = dy - j1 + (1.0 / 6.0), z1 = dz - k1 + (1.0 / 6.0);
        double x2 = dx - i2 + (1.0 / 3.0), y2 = dy - j2 + (1.0 / 3.0), z2 = dz - k2 + (1.0 / 3.0);
        double x3 = dx - 0.5, y3 = dy - 0.5, z3 = dz - 0.5;

        int ip = (int)i, jp = (int)j, kp = (int)k;
        double[] g0 = gtab[((int)ptab[(int)(ip      + ptab[(int)(jp      + ptab[(int)kp        & 0xff]) & 0xff]) & 0xff] & 0xff) % 12];
        double[] g1 = gtab[((int)ptab[(int)(ip + i1 + ptab[(int)(jp + j1 + ptab[(int)(kp + k1) & 0xff]) & 0xff]) & 0xff] & 0xff) % 12];
        double[] g2 = gtab[((int)ptab[(int)(ip + i2 + ptab[(int)(jp + j2 + ptab[(int)(kp + k2) & 0xff]) & 0xff]) & 0xff] & 0xff) % 12];
        double[] g3 = gtab[((int)ptab[(int)(ip +  1 + ptab[(int)(jp +  1 + ptab[(int)(kp +  1) & 0xff]) & 0xff]) & 0xff] & 0xff) % 12];

        double n0 = 0.6 - (dx * dx) - (dy * dy) - (dz * dz);
        double n1 = 0.6 - (x1 * x1) - (y1 * y1) - (z1 * z1);
        double n2 = 0.6 - (x2 * x2) - (y2 * y2) - (z2 * z2);
        double n3 = 0.6 - (x3 * x3) - (y3 * y3) - (z3 * z3);

        double v = 0.0;
        if(n0 > 0) v += n0 * n0 * n0 * n0 * ((g0[0] * dx) + (g0[1] * dy) + (g0[2] * dz));
        if(n1 > 0) v += n1 * n1 * n1 * n1 * ((g1[0] * x1) + (g1[1] * y1) + (g1[2] * z1));
        if(n2 > 0) v += n2 * n2 * n2 * n2 * ((g2[0] * x2) + (g2[1] * y2) + (g2[2] * z2));
        if(n3 > 0) v += n3 * n3 * n3 * n3 * ((g3[0] * x3) + (g3[1] * y3) + (g3[2] * z3));

        return(min(max(v * 32, -1.0), 1.0));
    }

    public double getr(double lo, double hi, double r, double x, double y, double z) {
        return((((get(r, x, y, z) * 0.5) + 0.5) * (hi - lo)) + lo);
    }

    public int geti(int lo, int hi, double r, double x, double y, double z) {
        return(min((int)(((get(r, x, y, z) * 0.5) + 0.5) * (hi - lo)), (int)((hi - lo) - 1)) + lo);
    }
}