/// <summary>
/// Get the noise function at a given position specified by f
/// </summary>
/// <param name="f">A position in space (dimension 1-4)</param>
/// <returns>Amplitude of noise from this pass at the given location.</returns>
public float GetNoise(float[] f)
{
int[] n = new int[MaxDimensions]; // Indexes to pass to lattice function
float[] r = new float[MaxDimensions]; // Remainders to pass to lattice function
float[] w = new float[MaxDimensions]; // Cubic values to pass to interpolation function
for (int i = 0; i < m_nDimensions; i++)
{
n[i] = (int)Math.Floor(f[i]);
r[i] = f[i] - n[i];
w[i] = NoiseHelper.Cubic(r[i]);
}
float fValue;
switch (m_nDimensions)
{
case 1:
fValue = Lerp(Lattice(n[0], r[0]),
Lattice(n[0] + 1, r[0] - 1),
w[0]);
break;
case 2:
fValue = Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1]),
Lattice(n[0] + 1, r[0] - 1, n[1], r[1]),
w[0]),
Lerp(Lattice(n[0], r[0], n[1] + 1, r[1] - 1),
Lattice(n[0] + 1, r[0] - 1, n[1] + 1, r[1] - 1),
w[0]),
w[1]);
break;
case 3:
fValue = Lerp(Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2], r[2]),
Lattice(n[0] + 1, r[0] - 1, n[1], r[1], n[2], r[2]),
w[0]),
Lerp(Lattice(n[0], r[0], n[1] + 1, r[1] - 1, n[2], r[2]),
Lattice(n[0] + 1, r[0] - 1, n[1] + 1, r[1] - 1, n[2], r[2]),
w[0]),
w[1]),
Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2] + 1, r[2] - 1),
Lattice(n[0] + 1, r[0] - 1, n[1], r[1], n[2] + 1, r[2] - 1),
w[0]),
Lerp(Lattice(n[0], r[0], n[1] + 1, r[1] - 1, n[2] + 1, r[2] - 1),
Lattice(n[0] + 1, r[0] - 1, n[1] + 1, r[1] - 1, n[2] + 1, r[2] - 1),
w[0]),
w[1]),
w[2]);
break;
case 4:
fValue = Lerp(Lerp(Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2], r[2], n[3], r[3]),
Lattice(n[0] + 1, r[0] - 1, n[1], r[1], n[2], r[2], n[3], r[3]),
w[0]),
Lerp(Lattice(n[0], r[0], n[1] + 1, r[1] - 1, n[2], r[2], n[3], r[3]),
Lattice(n[0] + 1, r[0] - 1, n[1] + 1, r[1] - 1, n[2], r[2], n[3], r[3]),
w[0]),
w[1]),
Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2] + 1, r[2] - 1, n[3], r[3]),
Lattice(n[0] + 1, r[0] - 1, n[1], r[1], n[2] + 1, r[2] - 1, n[3], r[3]),
w[0]),
Lerp(Lattice(n[0], r[0], n[1] + 1, r[1] - 1, n[2] + 1, r[2] - 1),
Lattice(n[0] + 1, r[0] - 1, n[1] + 1, r[1] - 1, n[2] + 1, r[2] - 1, n[3], r[3]),
w[0]),
w[1]),
w[2]),
Lerp(Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2], r[2], n[3] + 1, r[3] - 1),
Lattice(n[0] + 1, r[0] - 1, n[1], r[1], n[2], r[2], n[3] + 1, r[3] - 1),
w[0]),
Lerp(Lattice(n[0], r[0], n[1] + 1, r[1] - 1, n[2], r[2], n[3] + 1, r[3] - 1),
Lattice(n[0] + 1, r[0] - 1, n[1] + 1, r[1] - 1, n[2], r[2], n[3] + 1, r[3] - 1),
w[0]),
w[1]),
Lerp(Lerp(Lattice(n[0], r[0], n[1], r[1], n[2] + 1, r[2] - 1, n[3] + 1, r[3] - 1),
Lattice(n[0] + 1, r[0] - 1, n[1], r[1], n[2] + 1, r[2] - 1, n[3] + 1, r[3] - 1),
w[0]),
Lerp(Lattice(n[0], r[0], n[1] + 1, r[1] - 1, n[2] + 1, r[2] - 1),
Lattice(n[0] + 1, r[0] - 1, n[1] + 1, r[1] - 1, n[2] + 1, r[2] - 1, n[3] + 1, r[3] - 1),
w[0]),
w[1]),
w[2]),
w[3]);
break;
default:
throw new Exception("Invalid value for dimension");
}
return(NoiseHelper.Clamp(-0.99999f, 0.99999f, fValue));
}
private static float Lerp(float a, float b, float x)
{
return(NoiseHelper.Lerp(a, b, x));
}
