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| 1 | import java.util.Random; | |
| 2 | ||
| 3 | public class PerlinNoise {
| |
| 4 | ||
| 5 | final static int TABLE_SIZE = 64; | |
| 6 | ||
| 7 | private final static double WEIGHT(double T) {
| |
| 8 | return ((2.0 * Math.abs(T) - 3.0) * (T) * (T) + 1.0); | |
| 9 | } | |
| 10 | ||
| 11 | private final int CLAMP(int val, int min, int max) {
| |
| 12 | return ((val < min ? min : val) > max ? max : val); | |
| 13 | } | |
| 14 | ||
| 15 | private final double CLAMP(double val, double min, double max) {
| |
| 16 | return ((val < min ? min : val) > max ? max : val); | |
| 17 | } | |
| 18 | ||
| 19 | final int SCALE_WIDTH = 128; | |
| 20 | final double MIN_SIZE = 0.1; | |
| 21 | final double MAX_SIZE = 16.0; | |
| 22 | ||
| 23 | private boolean tilable = false; | |
| 24 | private boolean turbulent = false; | |
| 25 | private long seed = 0; | |
| 26 | private int detail = 1; | |
| 27 | private double size = 8.0; | |
| 28 | ||
| 29 | private static int clip; | |
| 30 | private static double offset, factor; | |
| 31 | static int[] perm_tab = new int[TABLE_SIZE]; | |
| 32 | static Vector2d[] grad_tab = new Vector2d[TABLE_SIZE]; | |
| 33 | ||
| 34 | public PerlinNoise(long seed) {
| |
| 35 | this.seed = seed; | |
| 36 | init(); | |
| 37 | } | |
| 38 | ||
| 39 | public double noise2(double x, double y) {
| |
| 40 | x /= 100; | |
| 41 | y /= 100; | |
| 42 | return noise(x, y); | |
| 43 | } | |
| 44 | ||
| 45 | void init() {
| |
| 46 | int i, j, k, t; | |
| 47 | double m; | |
| 48 | Random r; | |
| 49 | ||
| 50 | r = new Random(seed); | |
| 51 | ||
| 52 | /* Force sane parameters */ | |
| 53 | detail = CLAMP(detail, 0, 15); | |
| 54 | size = CLAMP(size, MIN_SIZE, MAX_SIZE); | |
| 55 | ||
| 56 | /* Set scaling factors */ | |
| 57 | if (tilable) {
| |
| 58 | this.size = Math.ceil(size); | |
| 59 | clip = (int) size; | |
| 60 | } | |
| 61 | ||
| 62 | /* Set totally empiric normalization values */ | |
| 63 | if (turbulent) {
| |
| 64 | offset = 0.0; | |
| 65 | factor = 1.0; | |
| 66 | } else {
| |
| 67 | offset = 0.94; | |
| 68 | factor = 0.526; | |
| 69 | } | |
| 70 | ||
| 71 | /* Initialize the permutation table */ | |
| 72 | for (i = 0; i < TABLE_SIZE; i++) | |
| 73 | perm_tab[i] = i; | |
| 74 | ||
| 75 | for (i = 0; i < (TABLE_SIZE >> 1); i++) {
| |
| 76 | j = r.nextInt(TABLE_SIZE); | |
| 77 | k = r.nextInt(TABLE_SIZE); | |
| 78 | t = perm_tab[j]; | |
| 79 | perm_tab[j] = perm_tab[k]; | |
| 80 | perm_tab[k] = t; | |
| 81 | } | |
| 82 | ||
| 83 | /* Initialize the gradient table */ | |
| 84 | for (i = 0; i < TABLE_SIZE; i++) {
| |
| 85 | grad_tab[i] = new Vector2d(); | |
| 86 | do {
| |
| 87 | grad_tab[i].setX((r.nextDouble() * 2) - 1); | |
| 88 | grad_tab[i].setY((r.nextDouble() * 2) - 1); | |
| 89 | m = grad_tab[i].getX() * grad_tab[i].getX() + grad_tab[i].getY() * grad_tab[i].getY(); | |
| 90 | } while (m == 0.0 || m > 1.0); | |
| 91 | ||
| 92 | m = 1.0 / Math.sqrt(m); | |
| 93 | grad_tab[i].setX(grad_tab[i].getX() * m); | |
| 94 | grad_tab[i].setY(grad_tab[i].getY() * m); | |
| 95 | } | |
| 96 | ||
| 97 | r = null; | |
| 98 | } | |
| 99 | ||
| 100 | double plain_noise(double x, double y, int s) {
| |
| 101 | Vector2d v = new Vector2d(); | |
| 102 | int a, b, i, j, n; | |
| 103 | double sum; | |
| 104 | ||
| 105 | sum = 0.0; | |
| 106 | x *= s; | |
| 107 | y *= s; | |
| 108 | a = (int) Math.floor(x); | |
| 109 | b = (int) Math.floor(y); | |
| 110 | ||
| 111 | for (i = 0; i < 2; i++) | |
| 112 | for (j = 0; j < 2; j++) {
| |
| 113 | if (tilable) | |
| 114 | - | // n = perm_tab[(((a + i) % (xclip * s)) + perm_tab[((b + j) |
| 114 | + | |
| 115 | - | // % (yclip * s)) % TABLE_SIZE]) % TABLE_SIZE]; |
| 115 | + | |
| 116 | n = perm_tab[betterMod(a + i + perm_tab[betterMod(b + j, TABLE_SIZE)], TABLE_SIZE)]; | |
| 117 | v.setX(x - a - i); | |
| 118 | v.setY(y - b - j); | |
| 119 | sum += WEIGHT(v.getX()) * WEIGHT(v.getY()) * (grad_tab[n].getX() * v.getX() + grad_tab[n].getY() * v.getY()); | |
| 120 | } | |
| 121 | ||
| 122 | return sum / s; | |
| 123 | } | |
| 124 | ||
| 125 | /** Modified modulus, so that negative numbers wrap correctly! */ | |
| 126 | private int betterMod(int val, int range) {
| |
| 127 | return (val % range + range) % range; | |
| 128 | } | |
| 129 | ||
| 130 | double noise(double x, double y) {
| |
| 131 | int i; | |
| 132 | int s; | |
| 133 | double sum; | |
| 134 | ||
| 135 | s = 1; | |
| 136 | sum = 0.0; | |
| 137 | x *= size; | |
| 138 | y *= size; | |
| 139 | ||
| 140 | for (i = 0; i <= detail; i++) {
| |
| 141 | if (turbulent) | |
| 142 | sum += Math.abs(plain_noise(x, y, s)); | |
| 143 | else | |
| 144 | sum += plain_noise(x, y, s); | |
| 145 | s <<= 1; | |
| 146 | } | |
| 147 | ||
| 148 | return (sum + offset) * factor; | |
| 149 | } | |
| 150 | } |