KiCad PCB EDA Suite
PerlinNoise.cpp
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24 
41 #include "PerlinNoise.h"
42 #include <cmath>
43 #include <iostream>
44 #include <cmath>
45 #include <random>
46 #include <algorithm>
47 #include <numeric>
48 
49 // THIS IS A DIRECT TRANSLATION TO C++11 FROM THE REFERENCE
50 // JAVA IMPLEMENTATION OF THE IMPROVED PERLIN FUNCTION (see http://mrl.nyu.edu/~perlin/noise/)
51 // THE ORIGINAL JAVA IMPLEMENTATION IS COPYRIGHT 2002 KEN PERLIN
52 
53 // I ADDED AN EXTRA METHOD THAT GENERATES A NEW PERMUTATION VECTOR
54 // (THIS IS NOT PRESENT IN THE ORIGINAL IMPLEMENTATION)
55 
56 // Initialize with the reference values for the permutation vector
58 {
59 
60  // Initialize the permutation vector with the reference values
61  p = {
62  151,160,137,91,90,15,131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,
63  8,99,37,240,21,10,23,190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,
64  35,11,32,57,177,33,88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,
65  134,139,48,27,166,77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,
66  55,46,245,40,244,102,143,54, 65,25,63,161,1,216,80,73,209,76,132,187,208, 89,
67  18,169,200,196,135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,
68  250,124,123,5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,
69  189,28,42,223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167,
70  43,172,9,129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,
71  97,228,251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,
72  107,49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
73  138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180 };
74 
75  // Duplicate the permutation vector
76  auto oldsize = p.size();
77  p.resize( 2 * p.size() );
78  std::copy_n( p.begin(), oldsize, p.begin() + oldsize );
79 }
80 
81 
82 PerlinNoise::PerlinNoise( unsigned int seed )
83 {
84  p.resize( 256 );
85 
86  // Fill p with values from 0 to 255
87  std::iota( p.begin(), p.end(), 0 );
88 
89  // Initialize a random engine with seed
90  std::default_random_engine engine( seed );
91 
92  // Shuffle using the above random engine
93  std::shuffle( p.begin(), p.end(), engine );
94 
95  // Duplicate the permutation vector
96  auto oldsize = p.size();
97  p.resize( 2 * p.size() );
98  std::copy_n( p.begin(), oldsize, p.begin() + oldsize );
99 }
100 
101 
102 float PerlinNoise::noise( float x, float y, float z ) const
103 {
104  // Find the unit cube that contains the point
105  int X = static_cast<int>( std::floor( x ) ) & 255;
106  int Y = static_cast<int>( std::floor( y ) ) & 255;
107  int Z = static_cast<int>( std::floor( z ) ) & 255;
108 
109  // Find relative x, y,z of point in cube
110  x -= std::floor( x );
111  y -= std::floor( y );
112  z -= std::floor( z );
113 
114  // Compute fade curves for each of x, y, z
115  const float u = fade( x );
116  const float v = fade( y );
117  const float w = fade( z );
118 
119  // Hash coordinates of the 8 cube corners
120  const int A = p[X] + Y;
121  const int AA = p[A] + Z;
122  const int AB = p[A + 1] + Z;
123  const int B = p[X + 1] + Y;
124  const int BA = p[B] + Z;
125  const int BB = p[B + 1] + Z;
126 
127  // Add blended results from 8 corners of cube
128  const float res = lerp(
129  w,
130  lerp( v, lerp( u, grad( p[AA], x, y, z ), grad( p[BA], x - 1, y, z ) ),
131  lerp( u, grad( p[AB], x, y - 1, z ), grad( p[BB], x - 1, y - 1, z ) ) ),
132  lerp( v, lerp( u, grad( p[AA + 1], x, y, z - 1 ), grad( p[BA + 1], x - 1, y, z - 1 ) ),
133  lerp( u, grad( p[AB + 1], x, y - 1, z - 1 ),
134  grad( p[BB + 1], x - 1, y - 1, z - 1 ) ) ) );
135 
136  return (res + 1.0f) / 2.0f;
137 }
138 
139 
140 float PerlinNoise::noise( float x, float y ) const
141 {
142  // Find the unit cube that contains the point
143  int X = static_cast<int>( std::floor( x ) ) & 255;
144  int Y = static_cast<int>( std::floor( y ) ) & 255;
145 
146  // Find relative x, y,z of point in cube
147  x -= std::floor( x );
148  y -= std::floor( y );
149 
150  // Compute fade curves for each of x, y
151  const float u = fade( x );
152  const float v = fade( y );
153 
154  // Hash coordinates of the 8 cube corners
155  const int A = p[X] + Y;
156  const int AA = p[A] + 0;
157  const int AB = p[A + 1] + 0;
158  const int B = p[X + 1] + Y;
159  const int BA = p[B] + 0;
160  const int BB = p[B + 1] + 0;
161 
162  // Add blended results from 8 corners of cube
163  const float res = lerp( v, lerp( u, grad( p[AA], x, y ), grad( p[BA], x - 1, y ) ),
164  lerp( u, grad( p[AB], x, y - 1 ), grad( p[BB], x - 1, y - 1 ) ) );
165 
166  return ( res + 1.0f ) / 2.0f;
167 }
168 
169 
170 float PerlinNoise::fade( float t ) const
171 {
172  return t * t * t * ( t * ( t * 6.0f - 15.0f ) + 10.0f );
173 }
174 
175 
176 float PerlinNoise::lerp( float t, float a, float b ) const
177 {
178  return a + t * ( b - a );
179 }
180 
181 
182 float PerlinNoise::grad( int hash, float x, float y, float z ) const
183 {
184  const int h = hash & 15;
185 
186  // Convert lower 4 bits of hash inot 12 gradient directions
187  const float u = h < 8 ? x : y;
188  const float v = h < 4 ? y : h == 12 || h == 14 ? x : z;
189 
190  return ( ( h & 1 ) == 0 ? u : -u ) + ( ( h & 2 ) == 0 ? v : -v );
191 }
192 
193 
194 float PerlinNoise::grad( int hash, float x, float y ) const
195 {
196  const int h = hash & 15;
197 
198  // Convert lower 4 bits of hash inot 12 gradient directions
199  const float u = h < 8 ? x : y;
200  const float v = h < 4 ? y : h == 12 || h == 14 ? x : 0.0f;
201 
202  return ( ( h & 1 ) == 0 ? u : -u ) + ( ( h & 2 ) == 0 ? v : -v );
203 }
PerlinNoise()
Initialize with the reference values for the permutation vector.
Definition: PerlinNoise.cpp:57
This source code comes from the project: https://github.com/sol-prog/Perlin_Noise.
std::vector< int > p
Definition: PerlinNoise.h:79
float grad(int hash, float x, float y, float z) const
float fade(float t) const
float lerp(float t, float a, float b) const
float noise(float x, float y, float z) const