Isosurface.SimplexNoise.SeamlessNoiseAbs C# (CSharp) Method

        public static float SeamlessNoiseAbs(float x, float y, float dx, float dy, float xyOffset)
        {
            float s = x;
            float t = y;

            float nx = xyOffset + (float)Math.Cos(s * 2.0f * Math.PI) * dx / (float)(2.0f * Math.PI);
            float ny = xyOffset + (float)Math.Cos(t * 2.0f * Math.PI) * dy / (float)(2.0f * Math.PI);
            float nz = xyOffset + (float)Math.Sin(s * 2.0f * Math.PI) * dx / (float)(2.0f * Math.PI);
            float nw = xyOffset + (float)Math.Sin(t * 2.0f * Math.PI) * dy / (float)(2.0f * Math.PI);

            return (Noise(nx, ny, nz, nw) + 1.0f) * 0.5f;
        }