001: package org.jvnet.substance.utils;
002:
003: /**
004: * A class for producing Perlin-inspired noise. The code written by Ken Perlin.
005: *
006: * @author Ken Perlin http://mrl.nyu.edu/~perlin/
007: */
008: public class PerlinNoiseGenerator {
009: /**
010: * Returns noise for the specified coordinates.
011: *
012: * @param x
013: * X coordinate.
014: * @param y
015: * Y coordinate.
016: * @param z
017: * Z coordinate.
018: * @return Noise for the specified coordinates.
019: */
020: static public double noise(double x, double y, double z) {
021: int X = (int) Math.floor(x) & 255, // FIND UNIT CUBE THAT
022: Y = (int) Math.floor(y) & 255, // CONTAINS POINT.
023: Z = (int) Math.floor(z) & 255;
024: x -= Math.floor(x); // FIND RELATIVE X,Y,Z
025: y -= Math.floor(y); // OF POINT IN CUBE.
026: z -= Math.floor(z);
027: double u = fade(x), // COMPUTE FADE CURVES
028: v = fade(y), // FOR EACH OF X,Y,Z.
029: w = fade(z);
030: int A = p[X] + Y, AA = p[A] + Z, AB = p[A + 1] + Z, // HASH COORDINATES
031: // OF
032: B = p[X + 1] + Y, BA = p[B] + Z, BB = p[B + 1] + Z; // THE 8 CUBE
033: // CORNERS,
034:
035: return lerp(w, lerp(v, lerp(u, grad(p[AA], x, y, z), // AND ADD
036: grad(p[BA], x - 1, y, z)), // BLENDED
037: lerp(u, grad(p[AB], x, y - 1, z), // RESULTS
038: grad(p[BB], x - 1, y - 1, z))),// FROM 8
039: lerp(v, lerp(u, grad(p[AA + 1], x, y, z - 1), // CORNERS
040: grad(p[BA + 1], x - 1, y, z - 1)), // OF CUBE
041: lerp(u, grad(p[AB + 1], x, y - 1, z - 1), grad(
042: p[BB + 1], x - 1, y - 1, z - 1))));
043: }
044:
045: /**
046: * Fades the specified value.
047: *
048: * @param t Value to fade.
049: * @return faded value.
050: */
051: static double fade(double t) {
052: return t * t * t * (t * (t * 6 - 15) + 10);
053: }
054:
055: /**
056: * Interpolates the specified value.
057: *
058: * @param t Value.
059: * @param a Starting interpolation value.
060: * @param b Ending interpolation value.
061: * @return Interpolated value.
062: */
063: static double lerp(double t, double a, double b) {
064: return a + t * (b - a);
065: }
066:
067: /**
068: * @param hash
069: * @param x
070: * @param y
071: * @param z
072: * @return
073: */
074: static double grad(int hash, double x, double y, double z) {
075: int h = hash & 15; // CONVERT LO 4 BITS OF HASH CODE
076: double u = h < 8 ? x : y, // INTO 12 GRADIENT DIRECTIONS.
077: v = h < 4 ? y : (h == 12) || (h == 14) ? x : z;
078: return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
079: }
080:
081: /**
082: * Permutations.
083: */
084: static final int p[] = new int[512];
085:
086: /**
087: * Permutations.
088: */
089: static final int permutation[] = { 151, 160, 137, 91, 90, 15, 131,
090: 13, 201, 95, 96, 53, 194, 233, 7, 225, 140, 36, 103, 30,
091: 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148, 247, 120,
092: 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11,
093: 32, 57, 177, 33, 88, 237, 149, 56, 87, 174, 20, 125, 136,
094: 171, 168, 68, 175, 74, 165, 71, 134, 139, 48, 27, 166, 77,
095: 146, 158, 231, 83, 111, 229, 122, 60, 211, 133, 230, 220,
096: 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54, 65, 25,
097: 63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18,
098: 169, 200, 196, 135, 130, 116, 188, 159, 86, 164, 100, 109,
099: 198, 173, 186, 3, 64, 52, 217, 226, 250, 124, 123, 5, 202,
100: 38, 147, 118, 126, 255, 82, 85, 212, 207, 206, 59, 227, 47,
101: 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213, 119, 248,
102: 152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172,
103: 9, 129, 22, 39, 253, 19, 98, 108, 110, 79, 113, 224, 232,
104: 178, 185, 112, 104, 218, 246, 97, 228, 251, 34, 242, 193,
105: 238, 210, 144, 12, 191, 179, 162, 241, 81, 51, 145, 235,
106: 249, 14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157,
107: 184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138,
108: 236, 205, 93, 222, 114, 67, 29, 24, 72, 243, 141, 128, 195,
109: 78, 66, 215, 61, 156, 180 };
110: static {
111: for (int i = 0; i < 256; i++)
112: p[256 + i] = p[i] = permutation[i];
113: }
114: }
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