org.bukkit.util.noise.SimplexNoiseGenerator Maven / Gradle / Ivy
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package org.bukkit.util.noise;
import org.bukkit.World;
import java.util.Random;
/**
* Generates simplex-based noise.
*
* This is a modified version of the freely published version in the paper by
* Stefan Gustavson at
*
* http://staffwww.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
*/
public class SimplexNoiseGenerator extends PerlinNoiseGenerator {
protected static final double SQRT_3 = Math.sqrt(3);
protected static final double SQRT_5 = Math.sqrt(5);
protected static final double F2 = 0.5 * (SQRT_3 - 1);
protected static final double G2 = (3 - SQRT_3) / 6;
protected static final double G22 = G2 * 2.0 - 1;
protected static final double F3 = 1.0 / 3.0;
protected static final double G3 = 1.0 / 6.0;
protected static final double F4 = (SQRT_5 - 1.0) / 4.0;
protected static final double G4 = (5.0 - SQRT_5) / 20.0;
protected static final double G42 = G4 * 2.0;
protected static final double G43 = G4 * 3.0;
protected static final double G44 = G4 * 4.0 - 1.0;
protected static final int[][] grad4 = {{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},
{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, 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, 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}};
protected static final int[][] simplex = {
{0, 1, 2, 3}, {0, 1, 3, 2}, {0, 0, 0, 0}, {0, 2, 3, 1}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {1, 2, 3, 0},
{0, 2, 1, 3}, {0, 0, 0, 0}, {0, 3, 1, 2}, {0, 3, 2, 1}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {1, 3, 2, 0},
{0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0},
{1, 2, 0, 3}, {0, 0, 0, 0}, {1, 3, 0, 2}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {2, 3, 0, 1}, {2, 3, 1, 0},
{1, 0, 2, 3}, {1, 0, 3, 2}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {2, 0, 3, 1}, {0, 0, 0, 0}, {2, 1, 3, 0},
{0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0},
{2, 0, 1, 3}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {3, 0, 1, 2}, {3, 0, 2, 1}, {0, 0, 0, 0}, {3, 1, 2, 0},
{2, 1, 0, 3}, {0, 0, 0, 0}, {0, 0, 0, 0}, {0, 0, 0, 0}, {3, 1, 0, 2}, {0, 0, 0, 0}, {3, 2, 0, 1}, {3, 2, 1, 0}};
private static final SimplexNoiseGenerator instance = new SimplexNoiseGenerator();
protected static double offsetW;
protected SimplexNoiseGenerator() {
super();
}
/**
* Creates a seeded simplex noise generator for the given world
*
* @param world World to construct this generator for
*/
public SimplexNoiseGenerator(World world) {
this(new Random(world.getSeed()));
}
/**
* Creates a seeded simplex noise generator for the given seed
*
* @param seed Seed to construct this generator for
*/
public SimplexNoiseGenerator(long seed) {
this(new Random(seed));
}
/**
* Creates a seeded simplex noise generator with the given Random
*
* @param rand Random to construct with
*/
public SimplexNoiseGenerator(Random rand) {
super(rand);
offsetW = rand.nextDouble() * 256;
}
protected static double dot(int[] g, double x, double y) {
return g[0] * x + g[1] * y;
}
protected static double dot(int[] g, double x, double y, double z) {
return g[0] * x + g[1] * y + g[2] * z;
}
protected static double dot(int[] g, double x, double y, double z, double w) {
return g[0] * x + g[1] * y + g[2] * z + g[3] * w;
}
/**
* Computes and returns the 1D unseeded simplex noise for the given
* coordinates in 1D space
*
* @param xin X coordinate
* @return Noise at given location, from range -1 to 1
*/
public static double getNoise(double xin) {
return instance.noise(xin);
}
/**
* Computes and returns the 2D unseeded simplex noise for the given
* coordinates in 2D space
*
* @param xin X coordinate
* @param yin Y coordinate
* @return Noise at given location, from range -1 to 1
*/
public static double getNoise(double xin, double yin) {
return instance.noise(xin, yin);
}
/**
* Computes and returns the 3D unseeded simplex noise for the given
* coordinates in 3D space
*
* @param xin X coordinate
* @param yin Y coordinate
* @param zin Z coordinate
* @return Noise at given location, from range -1 to 1
*/
public static double getNoise(double xin, double yin, double zin) {
return instance.noise(xin, yin, zin);
}
/**
* Computes and returns the 4D simplex noise for the given coordinates in
* 4D space
*
* @param x X coordinate
* @param y Y coordinate
* @param z Z coordinate
* @param w W coordinate
* @return Noise at given location, from range -1 to 1
*/
public static double getNoise(double x, double y, double z, double w) {
return instance.noise(x, y, z, w);
}
/**
* Gets the singleton unseeded instance of this generator
*
* @return Singleton
*/
public static SimplexNoiseGenerator getInstance() {
return instance;
}
@Override
public double noise(double xin, double yin, double zin) {
xin += offsetX;
yin += offsetY;
zin += offsetZ;
double n0, n1, n2, n3; // Noise contributions from the four corners
// Skew the input space to determine which simplex cell we're in
double s = (xin + yin + zin) * F3; // Very nice and simple skew factor for 3D
int i = floor(xin + s);
int j = floor(yin + s);
int k = floor(zin + s);
double t = (i + j + k) * G3;
double X0 = i - t; // Unskew the cell origin back to (x,y,z) space
double Y0 = j - t;
double Z0 = k - t;
double x0 = xin - X0; // The x,y,z distances from the cell origin
double y0 = yin - Y0;
double z0 = zin - Z0;
// For the 3D case, the simplex shape is a slightly irregular tetrahedron.
// Determine which simplex we are in.
int i1, j1, k1; // Offsets for second corner of simplex in (i,j,k) coords
int i2, j2, k2; // Offsets for third corner of simplex in (i,j,k) coords
if (x0 >= y0) {
if (y0 >= z0) {
i1 = 1;
j1 = 0;
k1 = 0;
i2 = 1;
j2 = 1;
k2 = 0;
} // X Y Z order
else if (x0 >= z0) {
i1 = 1;
j1 = 0;
k1 = 0;
i2 = 1;
j2 = 0;
k2 = 1;
} // X Z Y order
else {
i1 = 0;
j1 = 0;
k1 = 1;
i2 = 1;
j2 = 0;
k2 = 1;
} // Z X Y order
} else { // x0 y0) {
i1 = 1;
j1 = 0;
} // lower triangle, XY order: (0,0)->(1,0)->(1,1)
else {
i1 = 0;
j1 = 1;
} // upper triangle, YX order: (0,0)->(0,1)->(1,1)
// A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
// a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
// c = (3-sqrt(3))/6
double x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
double y1 = y0 - j1 + G2;
double x2 = x0 + G22; // Offsets for last corner in (x,y) unskewed coords
double y2 = y0 + G22;
// Work out the hashed gradient indices of the three simplex corners
int ii = i & 255;
int jj = j & 255;
int gi0 = perm[ii + perm[jj]] % 12;
int gi1 = perm[ii + i1 + perm[jj + j1]] % 12;
int gi2 = perm[ii + 1 + perm[jj + 1]] % 12;
// Calculate the contribution from the three corners
double t0 = 0.5 - x0 * x0 - y0 * y0;
if (t0 < 0) {
n0 = 0.0;
} else {
t0 *= t0;
n0 = t0 * t0 * dot(grad3[gi0], x0, y0); // (x,y) of grad3 used for 2D gradient
}
double t1 = 0.5 - x1 * x1 - y1 * y1;
if (t1 < 0) {
n1 = 0.0;
} else {
t1 *= t1;
n1 = t1 * t1 * dot(grad3[gi1], x1, y1);
}
double t2 = 0.5 - x2 * x2 - y2 * y2;
if (t2 < 0) {
n2 = 0.0;
} else {
t2 *= t2;
n2 = t2 * t2 * dot(grad3[gi2], x2, y2);
}
// Add contributions from each corner to get the final noise value.
// The result is scaled to return values in the interval [-1,1].
return 70.0 * (n0 + n1 + n2);
}
/**
* Computes and returns the 4D simplex noise for the given coordinates in
* 4D space
*
* @param x X coordinate
* @param y Y coordinate
* @param z Z coordinate
* @param w W coordinate
* @return Noise at given location, from range -1 to 1
*/
public double noise(double x, double y, double z, double w) {
x += offsetX;
y += offsetY;
z += offsetZ;
w += offsetW;
double n0, n1, n2, n3, n4; // Noise contributions from the five corners
// Skew the (x,y,z,w) space to determine which cell of 24 simplices we're in
double s = (x + y + z + w) * F4; // Factor for 4D skewing
int i = floor(x + s);
int j = floor(y + s);
int k = floor(z + s);
int l = floor(w + s);
double t = (i + j + k + l) * G4; // Factor for 4D unskewing
double X0 = i - t; // Unskew the cell origin back to (x,y,z,w) space
double Y0 = j - t;
double Z0 = k - t;
double W0 = l - t;
double x0 = x - X0; // The x,y,z,w distances from the cell origin
double y0 = y - Y0;
double z0 = z - Z0;
double w0 = w - W0;
// For the 4D case, the simplex is a 4D shape I won't even try to describe.
// To find out which of the 24 possible simplices we're in, we need to
// determine the magnitude ordering of x0, y0, z0 and w0.
// The method below is a good way of finding the ordering of x,y,z,w and
// then find the correct traversal order for the simplex we’re in.
// First, six pair-wise comparisons are performed between each possible pair
// of the four coordinates, and the results are used to add up binary bits
// for an integer index.
int c1 = (x0 > y0) ? 32 : 0;
int c2 = (x0 > z0) ? 16 : 0;
int c3 = (y0 > z0) ? 8 : 0;
int c4 = (x0 > w0) ? 4 : 0;
int c5 = (y0 > w0) ? 2 : 0;
int c6 = (z0 > w0) ? 1 : 0;
int c = c1 + c2 + c3 + c4 + c5 + c6;
int i1, j1, k1, l1; // The integer offsets for the second simplex corner
int i2, j2, k2, l2; // The integer offsets for the third simplex corner
int i3, j3, k3, l3; // The integer offsets for the fourth simplex corner
// simplex[c] is a 4-vector with the numbers 0, 1, 2 and 3 in some order.
// Many values of c will never occur, since e.g. x>y>z>w makes x= 3 ? 1 : 0;
j1 = simplex[c][1] >= 3 ? 1 : 0;
k1 = simplex[c][2] >= 3 ? 1 : 0;
l1 = simplex[c][3] >= 3 ? 1 : 0;
// The number 2 in the "simplex" array is at the second largest coordinate.
i2 = simplex[c][0] >= 2 ? 1 : 0;
j2 = simplex[c][1] >= 2 ? 1 : 0;
k2 = simplex[c][2] >= 2 ? 1 : 0;
l2 = simplex[c][3] >= 2 ? 1 : 0;
// The number 1 in the "simplex" array is at the second smallest coordinate.
i3 = simplex[c][0] >= 1 ? 1 : 0;
j3 = simplex[c][1] >= 1 ? 1 : 0;
k3 = simplex[c][2] >= 1 ? 1 : 0;
l3 = simplex[c][3] >= 1 ? 1 : 0;
// The fifth corner has all coordinate offsets = 1, so no need to look that up.
double x1 = x0 - i1 + G4; // Offsets for second corner in (x,y,z,w) coords
double y1 = y0 - j1 + G4;
double z1 = z0 - k1 + G4;
double w1 = w0 - l1 + G4;
double x2 = x0 - i2 + G42; // Offsets for third corner in (x,y,z,w) coords
double y2 = y0 - j2 + G42;
double z2 = z0 - k2 + G42;
double w2 = w0 - l2 + G42;
double x3 = x0 - i3 + G43; // Offsets for fourth corner in (x,y,z,w) coords
double y3 = y0 - j3 + G43;
double z3 = z0 - k3 + G43;
double w3 = w0 - l3 + G43;
double x4 = x0 + G44; // Offsets for last corner in (x,y,z,w) coords
double y4 = y0 + G44;
double z4 = z0 + G44;
double w4 = w0 + G44;
// Work out the hashed gradient indices of the five simplex corners
int ii = i & 255;
int jj = j & 255;
int kk = k & 255;
int ll = l & 255;
int gi0 = perm[ii + perm[jj + perm[kk + perm[ll]]]] % 32;
int gi1 = perm[ii + i1 + perm[jj + j1 + perm[kk + k1 + perm[ll + l1]]]] % 32;
int gi2 = perm[ii + i2 + perm[jj + j2 + perm[kk + k2 + perm[ll + l2]]]] % 32;
int gi3 = perm[ii + i3 + perm[jj + j3 + perm[kk + k3 + perm[ll + l3]]]] % 32;
int gi4 = perm[ii + 1 + perm[jj + 1 + perm[kk + 1 + perm[ll + 1]]]] % 32;
// Calculate the contribution from the five corners
double t0 = 0.6 - x0 * x0 - y0 * y0 - z0 * z0 - w0 * w0;
if (t0 < 0) {
n0 = 0.0;
} else {
t0 *= t0;
n0 = t0 * t0 * dot(grad4[gi0], x0, y0, z0, w0);
}
double t1 = 0.6 - x1 * x1 - y1 * y1 - z1 * z1 - w1 * w1;
if (t1 < 0) {
n1 = 0.0;
} else {
t1 *= t1;
n1 = t1 * t1 * dot(grad4[gi1], x1, y1, z1, w1);
}
double t2 = 0.6 - x2 * x2 - y2 * y2 - z2 * z2 - w2 * w2;
if (t2 < 0) {
n2 = 0.0;
} else {
t2 *= t2;
n2 = t2 * t2 * dot(grad4[gi2], x2, y2, z2, w2);
}
double t3 = 0.6 - x3 * x3 - y3 * y3 - z3 * z3 - w3 * w3;
if (t3 < 0) {
n3 = 0.0;
} else {
t3 *= t3;
n3 = t3 * t3 * dot(grad4[gi3], x3, y3, z3, w3);
}
double t4 = 0.6 - x4 * x4 - y4 * y4 - z4 * z4 - w4 * w4;
if (t4 < 0) {
n4 = 0.0;
} else {
t4 *= t4;
n4 = t4 * t4 * dot(grad4[gi4], x4, y4, z4, w4);
}
// Sum up and scale the result to cover the range [-1,1]
return 27.0 * (n0 + n1 + n2 + n3 + n4);
}
}