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    <p>Perlin noise is completely controlled by the different variables you set, i.e. amplitude, frequency and persistance. The amount of octaves has a little change, but not much. In code that I have written in the past I have just played around with the order of magnitude of the frequency and persistance until I have gotten what I needed. I can try to find my old source if needed.</p> <h2>PerlinNoise.h</h2> <pre><code>#pragma once class PerlinNoise { public: // Constructor PerlinNoise(); PerlinNoise(double _persistence, double _frequency, double _amplitude, int _octaves, int _randomseed); // Get Height double GetHeight(double x, double y) const; // Get double Persistence() const { return persistence; } double Frequency() const { return frequency; } double Amplitude() const { return amplitude; } int Octaves() const { return octaves; } int RandomSeed() const { return randomseed; } // Set void Set(double _persistence, double _frequency, double _amplitude, int _octaves, int _randomseed); void SetPersistence(double _persistence) { persistence = _persistence; } void SetFrequency( double _frequency) { frequency = _frequency; } void SetAmplitude( double _amplitude) { amplitude = _amplitude; } void SetOctaves( int _octaves) { octaves = _octaves; } void SetRandomSeed( int _randomseed) { randomseed = _randomseed; } private: double Total(double i, double j) const; double GetValue(double x, double y) const; double Interpolate(double x, double y, double a) const; double Noise(int x, int y) const; double persistence, frequency, amplitude; int octaves, randomseed; }; </code></pre> <h2>PerlinNoise.cpp</h2> <pre><code>#include "PerlinNoise.h" PerlinNoise::PerlinNoise() { persistence = 0; frequency = 0; amplitude = 0; octaves = 0; randomseed = 0; } PerlinNoise::PerlinNoise(double _persistence, double _frequency, double _amplitude, int _octaves, int _randomseed) { persistence = _persistence; frequency = _frequency; amplitude = _amplitude; octaves = _octaves; randomseed = 2 + _randomseed * _randomseed; } void PerlinNoise::Set(double _persistence, double _frequency, double _amplitude, int _octaves, int _randomseed) { persistence = _persistence; frequency = _frequency; amplitude = _amplitude; octaves = _octaves; randomseed = 2 + _randomseed * _randomseed; } double PerlinNoise::GetHeight(double x, double y) const { return amplitude * Total(x, y); } double PerlinNoise::Total(double i, double j) const { //properties of one octave (changing each loop) double t = 0.0f; double _amplitude = 1; double freq = frequency; for(int k = 0; k &lt; octaves; k++) { t += GetValue(j * freq + randomseed, i * freq + randomseed) * _amplitude; _amplitude *= persistence; freq *= 2; } return t; } double PerlinNoise::GetValue(double x, double y) const { int Xint = (int)x; int Yint = (int)y; double Xfrac = x - Xint; double Yfrac = y - Yint; //noise values double n01 = Noise(Xint-1, Yint-1); double n02 = Noise(Xint+1, Yint-1); double n03 = Noise(Xint-1, Yint+1); double n04 = Noise(Xint+1, Yint+1); double n05 = Noise(Xint-1, Yint); double n06 = Noise(Xint+1, Yint); double n07 = Noise(Xint, Yint-1); double n08 = Noise(Xint, Yint+1); double n09 = Noise(Xint, Yint); double n12 = Noise(Xint+2, Yint-1); double n14 = Noise(Xint+2, Yint+1); double n16 = Noise(Xint+2, Yint); double n23 = Noise(Xint-1, Yint+2); double n24 = Noise(Xint+1, Yint+2); double n28 = Noise(Xint, Yint+2); double n34 = Noise(Xint+2, Yint+2); //find the noise values of the four corners double x0y0 = 0.0625*(n01+n02+n03+n04) + 0.125*(n05+n06+n07+n08) + 0.25*(n09); double x1y0 = 0.0625*(n07+n12+n08+n14) + 0.125*(n09+n16+n02+n04) + 0.25*(n06); double x0y1 = 0.0625*(n05+n06+n23+n24) + 0.125*(n03+n04+n09+n28) + 0.25*(n08); double x1y1 = 0.0625*(n09+n16+n28+n34) + 0.125*(n08+n14+n06+n24) + 0.25*(n04); //interpolate between those values according to the x and y fractions double v1 = Interpolate(x0y0, x1y0, Xfrac); //interpolate in x direction (y) double v2 = Interpolate(x0y1, x1y1, Xfrac); //interpolate in x direction (y+1) double fin = Interpolate(v1, v2, Yfrac); //interpolate in y direction return fin; } double PerlinNoise::Interpolate(double x, double y, double a) const { double negA = 1.0 - a; double negASqr = negA * negA; double fac1 = 3.0 * (negASqr) - 2.0 * (negASqr * negA); double aSqr = a * a; double fac2 = 3.0 * aSqr - 2.0 * (aSqr * a); return x * fac1 + y * fac2; //add the weighted factors } double PerlinNoise::Noise(int x, int y) const { int n = x + y * 57; n = (n &lt;&lt; 13) ^ n; int t = (n * (n * n * 15731 + 789221) + 1376312589) &amp; 0x7fffffff; return 1.0 - double(t) * 0.931322574615478515625e-9;/// 1073741824.0); } </code></pre>
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    1. COThanks for posting this source!
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    2. COI wrote it quite a while back. I'm glad someone could find some use of it.
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    3. COgreat post! This helped turn my own boring rolling hills into awesome looking mountain ranges! Perlin noise is awesome! thanks!
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