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output/Libraries/AForge.Math/AForge/Math/PerlinNoise.cs

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+using System;
+
+namespace AForge.Math;
+
+public class PerlinNoise
+{
+	private double initFrequency = 1.0;
+
+	private double initAmplitude = 1.0;
+
+	private double persistence = 0.65;
+
+	private int octaves = 4;
+
+	public double InitFrequency
+	{
+		get
+		{
+			return initFrequency;
+		}
+		set
+		{
+			initFrequency = value;
+		}
+	}
+
+	public double InitAmplitude
+	{
+		get
+		{
+			return initAmplitude;
+		}
+		set
+		{
+			initAmplitude = value;
+		}
+	}
+
+	public double Persistence
+	{
+		get
+		{
+			return persistence;
+		}
+		set
+		{
+			persistence = value;
+		}
+	}
+
+	public int Octaves
+	{
+		get
+		{
+			return octaves;
+		}
+		set
+		{
+			octaves = System.Math.Max(1, System.Math.Min(32, value));
+		}
+	}
+
+	public PerlinNoise()
+	{
+	}
+
+	public PerlinNoise(int octaves, double persistence)
+	{
+		this.octaves = octaves;
+		this.persistence = persistence;
+	}
+
+	public PerlinNoise(int octaves, double persistence, double initFrequency, double initAmplitude)
+	{
+		this.octaves = octaves;
+		this.persistence = persistence;
+		this.initFrequency = initFrequency;
+		this.initAmplitude = initAmplitude;
+	}
+
+	public double Function(double x)
+	{
+		double num = initFrequency;
+		double num2 = initAmplitude;
+		double num3 = 0.0;
+		for (int i = 0; i < octaves; i++)
+		{
+			num3 += SmoothedNoise(x * num) * num2;
+			num *= 2.0;
+			num2 *= persistence;
+		}
+		return num3;
+	}
+
+	public double Function2D(double x, double y)
+	{
+		double num = initFrequency;
+		double num2 = initAmplitude;
+		double num3 = 0.0;
+		for (int i = 0; i < octaves; i++)
+		{
+			num3 += SmoothedNoise(x * num, y * num) * num2;
+			num *= 2.0;
+			num2 *= persistence;
+		}
+		return num3;
+	}
+
+	private double Noise(int x)
+	{
+		int num = (x << 13) ^ x;
+		return 1.0 - (double)((num * (num * num * 15731 + 789221) + 1376312589) & 0x7FFFFFFF) / 1073741824.0;
+	}
+
+	private double Noise(int x, int y)
+	{
+		int num = x + y * 57;
+		num = (num << 13) ^ num;
+		return 1.0 - (double)((num * (num * num * 15731 + 789221) + 1376312589) & 0x7FFFFFFF) / 1073741824.0;
+	}
+
+	private double SmoothedNoise(double x)
+	{
+		int num = (int)x;
+		double a = x - (double)num;
+		return CosineInterpolate(Noise(num), Noise(num + 1), a);
+	}
+
+	private double SmoothedNoise(double x, double y)
+	{
+		int num = (int)x;
+		int num2 = (int)y;
+		double a = x - (double)num;
+		double a2 = y - (double)num2;
+		double x2 = Noise(num, num2);
+		double x3 = Noise(num + 1, num2);
+		double x4 = Noise(num, num2 + 1);
+		double x5 = Noise(num + 1, num2 + 1);
+		double x6 = CosineInterpolate(x2, x3, a);
+		double x7 = CosineInterpolate(x4, x5, a);
+		return CosineInterpolate(x6, x7, a2);
+	}
+
+	private double CosineInterpolate(double x1, double x2, double a)
+	{
+		double num = (1.0 - System.Math.Cos(a * System.Math.PI)) * 0.5;
+		return x1 * (1.0 - num) + x2 * num;
+	}
+}