public static void GetNoiseMap(
float[][] map, int dx = 0, int dy = 0,
int octaves = 1, float persistance = 0.5f, float lacunarity = 2.0f,
float sx = 1.0f, float sy = 1.0f, int seed = 0
)
{
var random = new Random(seed);
var width = map.GetWidth();
var height = map.GetHeight();
var pmin = 0.0f;
var pmax = 1.0f;
for (uint i = 1; i < octaves; ++i)
{
var ppow = Mathx.Pow(persistance, i);
pmin += ppow * 0.25f;
pmax += ppow * 0.75f;
}
var rdx = random.NextFloat(-99999.0f, +99999.0f);
var rdy = random.NextFloat(-99999.0f, +99999.0f);
var fx = 1.0f / (sx * width);
var fy = 1.0f / (sy * height);
for (int y = 0; y < height; ++y)
{
for (int x = 0; x < width; ++x)
{
float amplitude = 1.0f;
float frequency = 1.0f;
float value = 0.0f;
for (int i = 0; i < octaves; ++i)
{
float sampleX = ((x - dx) * fx) * frequency + rdx;
float sampleY = ((y - dy) * fy) * frequency + rdy;
float pv = Mathf.PerlinNoise(sampleX, sampleY);
value += pv * amplitude;
amplitude *= persistance;
frequency *= lacunarity;
}
map[x][y] = Mathf.SmoothStep(pmin, pmax, value);
}
}
}