Azmyth.Procedural.AzmythNoise.Interpolate C# (CSharp) Method

        double Interpolate(double x, double y, double a)
        {
            double negA = 1.0 - a;

            double negASqr = negA * negA;

            double fac1 = 3.0 * (negASqr) - 2.0 * (negASqr * negA);

            double aSqr = a * a;

            double fac2 = 3.0 * aSqr - 2.0 * (aSqr * a);

            return x * fac1 + y * fac2; //add the weighted factors
        }