/// <summary>
/// Initializes a new instance of the <see cref="Noise2D"/> class.
/// <para>
/// Performance is proportional to (largeFeatureScale/smallFeatureScale)^2, so if you need a wide range of feature sizes,
/// it's better to add multiple "frequency bands" of noise together.
/// </para>
/// </summary>
/// <param name="seed">A seed value to initialize the random number generator.</param>
/// <param name="smallFeatureSize">A value proportional to the size of the smallest details created by the noise.</param>
/// <param name="largeFeatureSize">A value proportional to the size of the largest details created by the noise.</param>
public Noise2D(uint seed, double smallFeatureSize, double largeFeatureSize)
{
_seedHash = HashCalculator.FromSeed(seed);
_scaleFactor = 1.0 / smallFeatureSize;
_blurFactor = largeFeatureSize / smallFeatureSize;
/* The blurred sampling is multiplied by this factor to make sure that the coefficients add up to the same value. */
_blurNormalizationFactor = 1.0 / (_blurFactor * _blurFactor);
}
private static double GetValue(HashCalculator hash)
{
/* Returns a deterministic "random" value in the range [-1, 1]. */
return hash.GetHashCode() * (-1.0 / int.MinValue);
}