Panda3D
perlinNoise3.cxx
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1/**
2 * PANDA 3D SOFTWARE
3 * Copyright (c) Carnegie Mellon University. All rights reserved.
4 *
5 * All use of this software is subject to the terms of the revised BSD
6 * license. You should have received a copy of this license along
7 * with this source code in a file named "LICENSE."
8 *
9 * @file perlinNoise3.cxx
10 * @author drose
11 * @date 2005-10-05
12 */
13
14#include "perlinNoise3.h"
15#include "cmath.h"
16
17/**
18 * Returns the noise function of the three inputs.
19 */
21noise(const LVecBase3d &value) const {
22 // Convert the vector to our local coordinate space.
23 LVecBase3d vec = _input_xform.xform_point(value);
24
25 double x = vec[0];
26 double y = vec[1];
27 double z = vec[2];
28
29 // Find unit cube that contains point.
30 double xf = cfloor(x);
31 double yf = cfloor(y);
32 double zf = cfloor(z);
33
34 int X = ((int)xf) & _table_size_mask;
35 int Y = ((int)yf) & _table_size_mask;
36 int Z = ((int)zf) & _table_size_mask;
37
38 // Find relative x,y,z of point in cube.
39 x -= xf;
40 y -= yf;
41 z -= zf;
42
43 // Compute fade curves for each of x,y,z.
44 double u = fade(x);
45 double v = fade(y);
46 double w = fade(z);
47
48 // Hash coordinates of the 8 cube corners. The 8 corners correspond to AA,
49 // BA, AB, BB, AA + 1, BA + 1, AB + 1, and BB + 1.
50 int A = _index[X] + Y;
51 int AA = _index[A] + Z;
52 int AB = _index[A + 1] + Z;
53 int B = _index[X + 1] + Y;
54 int BA = _index[B] + Z;
55 int BB = _index[B + 1] + Z;
56
57 // and add blended results from 8 corners of cube.
58 double result =
59 lerp(w, lerp(v, lerp(u, grad(_index[AA], x, y, z),
60 grad(_index[BA], x - 1, y, z)),
61 lerp(u, grad(_index[AB], x, y - 1, z),
62 grad(_index[BB], x - 1, y - 1, z))),
63 lerp(v, lerp(u, grad(_index[AA + 1], x, y, z - 1),
64 grad(_index[BA + 1], x - 1, y, z - 1)),
65 lerp(u, grad(_index[AB + 1], x, y - 1, z - 1),
66 grad(_index[BB + 1], x - 1, y - 1, z - 1))));
67
68 return result;
69}
70
71/**
72 * Come up with a random rotation to apply to the input coordinates. This
73 * will reduce the problem of the singularities on the axes, by sending the
74 * axes in some crazy direction.
75 */
76void PerlinNoise3::
77init_unscaled_xform() {
78 LRotationd rot(_randomizer.random_real_unit(),
79 _randomizer.random_real_unit(),
80 _randomizer.random_real_unit(),
81 _randomizer.random_real_unit());
82 rot.normalize();
83 rot.extract_to_matrix(_unscaled_xform);
84
85 // And come up with a random translation too, just so the singularity at (0,
86 // 0, 0) is also unpredicatable.
87 _unscaled_xform.set_row(3, LVecBase3d(_randomizer.random_real_unit(),
88 _randomizer.random_real_unit(),
89 _randomizer.random_real_unit()));
90}
double noise(double x, double y, double z) const
Returns the noise function of the three inputs.
Definition: perlinNoise3.I:100
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.