KiCad PCB EDA Suite
PerlinNoise.cpp
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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 
80 PerlinNoise::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 
100 float 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 
138 float 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 
168 float PerlinNoise::fade( float t ) const
169 {
170  return t * t * t * ( t * ( t * 6.0f - 15.0f ) + 10.0f );
171 }
172 
173 
174 float PerlinNoise::lerp( float t, float a, float b ) const
175 {
176  return a + t * ( b - a );
177 }
178 
179 
180 float 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 
192 float 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 }
PerlinNoise()
Initialize with the reference values for the permutation vector.
Definition: PerlinNoise.cpp:55
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