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