/// <summary>
/// See the documentation on the base class.
/// <seealso cref="Module"/>
/// </summary>
/// <param name="x">X coordinate</param>
/// <param name="y">Y coordinate</param>
/// <param name="z">Z coordinate</param>
/// <returns>Returns the computed value</returns>
public override double GetValue(double x, double y, double z)
{
// Get the values from the three Perlin noise modules and
// add each value to each coordinate of the input value. There are also
// some offsets added to the coordinates of the input values. This prevents
// the distortion modules from returning zero if the (x, y, z) coordinates,
// when multiplied by the frequency, are near an integer boundary. This is
// due to a property of gradient coherent noise, which returns zero at
// integer boundaries.
double x0, y0, z0;
double x1, y1, z1;
double x2, y2, z2;
x0 = x + (12414D / 65536D);
y0 = y + (65124D / 65536D);
z0 = z + (31337D / 65536D);
x1 = x + (26519D / 65536D);
y1 = y + (18128D / 65536D);
z1 = z + (60493D / 65536D);
x2 = x + (53820D / 65536D);
y2 = y + (11213D / 65536D);
z2 = z + (44845D / 65536D);
var xDistorted = x + (xDistort.GetValue(x0, y0, z0) * Power);
var yDistorted = y + (yDistort.GetValue(x1, y1, z1) * Power);
var zDistorted = z + (zDistort.GetValue(x2, y2, z2) * Power);
// Retrieve the output value at the offsetted input value instead of the
// original input value.
return(SourceModules[0].GetValue(xDistorted, yDistorted, zDistorted));
}
public void ScalePointTest(double sx, double sy, double sz)
{
var source = new Perlin();
var module = new ScalePoint
{
XScale = sx,
YScale = sy,
ZScale = sz,
Source0 = source,
};
for (int x = -1; x < 2; x++)
{
for (int y = -1; y < 2; y++)
{
for (int z = -1; z < 2; z++)
{
var expected = source.GetValue(x * sx, y * sy, z * sz);
var actual = module.GetValue(x, y, z);
Assert.Equal(expected, actual);
}
}
}
}
