public void CreateRandomHeightMap(int seed, float noiseSize, float persistence, int octaves)
{
for (var y = 0; y < HeightMapHeight; y++)
{
for (var x = 0; x < HeightMapWidth; x++)
{
var xf = (x / (float)HeightMapWidth) * noiseSize;
var yf = (y / (float)HeightMapHeight) * noiseSize;
var total = 0.0f;
for (var i = 0; i < octaves; i++)
{
var freq = (float)Math.Pow(2.0f, i);
var amp = (float)Math.Pow(persistence, i);
var tx = xf * freq;
var ty = yf * freq;
var txi = (int)tx;
var tyi = (int)ty;
var fracX = tx - txi;
var fracY = ty - tyi;
var v1 = MathF.Noise(txi + tyi * 57 + seed);
var v2 = MathF.Noise(txi + 1 + tyi * 57 + seed);
var v3 = MathF.Noise(txi + (tyi + 1) * 57 + seed);
var v4 = MathF.Noise(txi + 1 + (tyi + 1) * 57 + seed);
var i1 = MathF.CosInterpolate(v1, v2, fracX);
var i2 = MathF.CosInterpolate(v3, v4, fracX);
total += MathF.CosInterpolate(i1, i2, fracY) * amp;
}
var b = (int)(128 + total * 128.0f);
if (b < 0)
{
b = 0;
}
if (b > 255)
{
b = 255;
}
_heightMap[x + y * HeightMapHeight] = (b / 255.0f) * MaxHeight;
}
}
}
