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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 | } |