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PerlinNoise.cpp
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1/*
2 * This program source code file is part of KiCad, a free EDA CAD application.
3 *
4 * Copyright (C) 2016 Mario Luzeiro <[email protected]>
5 * Copyright (C) 2016-2021 KiCad Developers, see AUTHORS.txt for contributors.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2
10 * of the License, or (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, you may find one here:
19 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
20 * or you may search the http://www.gnu.org website for the version 2 license,
21 * or you may write to the Free Software Foundation, Inc.,
22 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
23 */
24
41#include "PerlinNoise.h"
42#include <cmath>
43#include <random>
44#include <algorithm>
45#include <numeric>
46
47// THIS IS A DIRECT TRANSLATION TO C++11 FROM THE REFERENCE
48// JAVA IMPLEMENTATION OF THE IMPROVED PERLIN FUNCTION (see http://mrl.nyu.edu/~perlin/noise/)
49// THE ORIGINAL JAVA IMPLEMENTATION IS COPYRIGHT 2002 KEN PERLIN
50
51// I ADDED AN EXTRA METHOD THAT GENERATES A NEW PERMUTATION VECTOR
52// (THIS IS NOT PRESENT IN THE ORIGINAL IMPLEMENTATION)
53
54// Initialize with the reference values for the permutation vector
56{
57
58 // Initialize the permutation vector with the reference values
59 p = {
60 151,160,137,91,90,15,131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,
61 8,99,37,240,21,10,23,190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,
62 35,11,32,57,177,33,88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,
63 134,139,48,27,166,77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,
64 55,46,245,40,244,102,143,54, 65,25,63,161,1,216,80,73,209,76,132,187,208, 89,
65 18,169,200,196,135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,
66 250,124,123,5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,
67 189,28,42,223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167,
68 43,172,9,129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,
69 97,228,251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,
70 107,49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
71 138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180 };
72
73 // Duplicate the permutation vector
74 auto oldsize = p.size();
75 p.resize( 2 * p.size() );
76 std::copy_n( p.begin(), oldsize, p.begin() + oldsize );
77}
78
79
80PerlinNoise::PerlinNoise( unsigned int seed )
81{
82 p.resize( 256 );
83
84 // Fill p with values from 0 to 255
85 std::iota( p.begin(), p.end(), 0 );
86
87 // Initialize a random engine with seed
88 std::default_random_engine engine( seed );
89
90 // Shuffle using the above random engine
91 std::shuffle( p.begin(), p.end(), engine );
92
93 // Duplicate the permutation vector
94 auto oldsize = p.size();
95 p.resize( 2 * p.size() );
96 std::copy_n( p.begin(), oldsize, p.begin() + oldsize );
97}
98
99
100float PerlinNoise::noise( float x, float y, float z ) const
101{
102 // Find the unit cube that contains the point
103 int X = static_cast<int>( std::floor( x ) ) & 255;
104 int Y = static_cast<int>( std::floor( y ) ) & 255;
105 int Z = static_cast<int>( std::floor( z ) ) & 255;
106
107 // Find relative x, y,z of point in cube
108 x -= std::floor( x );
109 y -= std::floor( y );
110 z -= std::floor( z );
111
112 // Compute fade curves for each of x, y, z
113 const float u = fade( x );
114 const float v = fade( y );
115 const float w = fade( z );
116
117 // Hash coordinates of the 8 cube corners
118 const int A = p[X] + Y;
119 const int AA = p[A] + Z;
120 const int AB = p[A + 1] + Z;
121 const int B = p[X + 1] + Y;
122 const int BA = p[B] + Z;
123 const int BB = p[B + 1] + Z;
124
125 // Add blended results from 8 corners of cube
126 const float res = lerp(
127 w,
128 lerp( v, lerp( u, grad( p[AA], x, y, z ), grad( p[BA], x - 1, y, z ) ),
129 lerp( u, grad( p[AB], x, y - 1, z ), grad( p[BB], x - 1, y - 1, z ) ) ),
130 lerp( v, lerp( u, grad( p[AA + 1], x, y, z - 1 ), grad( p[BA + 1], x - 1, y, z - 1 ) ),
131 lerp( u, grad( p[AB + 1], x, y - 1, z - 1 ),
132 grad( p[BB + 1], x - 1, y - 1, z - 1 ) ) ) );
133
134 return (res + 1.0f) / 2.0f;
135}
136
137
138float PerlinNoise::noise( float x, float y ) const
139{
140 // Find the unit cube that contains the point
141 int X = static_cast<int>( std::floor( x ) ) & 255;
142 int Y = static_cast<int>( std::floor( y ) ) & 255;
143
144 // Find relative x, y,z of point in cube
145 x -= std::floor( x );
146 y -= std::floor( y );
147
148 // Compute fade curves for each of x, y
149 const float u = fade( x );
150 const float v = fade( y );
151
152 // Hash coordinates of the 8 cube corners
153 const int A = p[X] + Y;
154 const int AA = p[A] + 0;
155 const int AB = p[A + 1] + 0;
156 const int B = p[X + 1] + Y;
157 const int BA = p[B] + 0;
158 const int BB = p[B + 1] + 0;
159
160 // Add blended results from 8 corners of cube
161 const float res = lerp( v, lerp( u, grad( p[AA], x, y ), grad( p[BA], x - 1, y ) ),
162 lerp( u, grad( p[AB], x, y - 1 ), grad( p[BB], x - 1, y - 1 ) ) );
163
164 return ( res + 1.0f ) / 2.0f;
165}
166
167
168float PerlinNoise::fade( float t ) const
169{
170 return t * t * t * ( t * ( t * 6.0f - 15.0f ) + 10.0f );
171}
172
173
174float PerlinNoise::lerp( float t, float a, float b ) const
175{
176 return a + t * ( b - a );
177}
178
179
180float PerlinNoise::grad( int hash, float x, float y, float z ) const
181{
182 const int h = hash & 15;
183
184 // Convert lower 4 bits of hash inot 12 gradient directions
185 const float u = h < 8 ? x : y;
186 const float v = h < 4 ? y : h == 12 || h == 14 ? x : z;
187
188 return ( ( h & 1 ) == 0 ? u : -u ) + ( ( h & 2 ) == 0 ? v : -v );
189}
190
191
192float PerlinNoise::grad( int hash, float x, float y ) const
193{
194 const int h = hash & 15;
195
196 // Convert lower 4 bits of hash inot 12 gradient directions
197 const float u = h < 8 ? x : y;
198 const float v = h < 4 ? y : h == 12 || h == 14 ? x : 0.0f;
199
200 return ( ( h & 1 ) == 0 ? u : -u ) + ( ( h & 2 ) == 0 ? v : -v );
201}
This source code comes from the project: https://github.com/sol-prog/Perlin_Noise.
float lerp(float t, float a, float b) const
PerlinNoise()
Initialize with the reference values for the permutation vector.
Definition: PerlinNoise.cpp:55
float grad(int hash, float x, float y, float z) const
std::vector< int > p
Definition: PerlinNoise.h:79
float noise(float x, float y, float z) const
float fade(float t) const
VECTOR3I res