double Influence(double cornerRotate, Utility.Vector pos)
{
cornerRotate *= Math.PI * 2;
//var toward = new Utility.Vector(
// Math.Cos(cornerRotate),
// Math.Sin(cornerRotate));
var toward = new Utility.Vector();
if (cornerRotate < Math.PI / 4 || cornerRotate > 7 * Math.PI / 4)
{
toward.X = 1;
toward.Y = Math.Sin(cornerRotate);
}
else if (cornerRotate < 3 * Math.PI / 4)
{
toward.X = Math.Cos(cornerRotate);
toward.Y = 1;
}
else if (cornerRotate < 5 * Math.PI / 4)
{
toward.X = -1;
toward.Y = Math.Sin(cornerRotate);
}
else
{
toward.X = Math.Cos(cornerRotate);
toward.Y = -1;
}
return(toward * pos);
}
public void GetNoise(double x, double y, ref double res)
{
var basex = (int)(x / wavelength);
var basey = (int)(y / wavelength);
if (basex == x && basey == y)
{
res = 0;
return;
}
//get gradient
var g00 = GetGradient(basex, basey);
var g10 = GetGradient(basex + 1, basey);
var g01 = GetGradient(basex, basey + 1);
var g11 = GetGradient(basex + 1, basey + 1);
var pos = new Utility.Vector(0, 0);
pos.X = (x - basex * wavelength) / wavelength; pos.Y = (y - basey * wavelength) / wavelength;
var n00 = Influence(g00, pos);
pos.X = (x - (basex + 1) * wavelength) / wavelength;
var n10 = Influence(g10, pos);
pos.X = (x - basex * wavelength) / wavelength; pos.Y = (y - (basey + 1) * wavelength) / wavelength;
var n01 = Influence(g01, pos);
pos.X = (x - (basex + 1) * wavelength) / wavelength;
var n11 = Influence(g11, pos);
var x_shortage = (x - basex * wavelength) / wavelength;
var y_shortage = (y - basey * wavelength) / wavelength;
var nx0 = n00 * (1 - Fade(x_shortage)) + n10 * Fade(x_shortage);
var nx1 = n01 * (1 - Fade(x_shortage)) + n11 * Fade(x_shortage);
res = nx0 * (1 - Fade(y_shortage)) + nx1 * Fade(y_shortage);
}