C# 归一化（如矢量）

Question

Code in my moving object:

ObjectX.Location.Add(Velocity * Utils.GetMoveDir(start, destination));

Utility function:

    public static PointF GetMoveDir(PointF start, PointF destination)
    {
        PointF substraction = destination.SubStract(start);
        if (substraction == PointF.Empty) // If-statement is needed because normalizing a zero value results in a NaN value
            return PointF.Empty;
        else
            return substraction.Normalize(); // <<<< I need something for this
    }

The extension I can't get to work:

    public static PointF Normalize(this PointF A)
    {
        throw new NotImplementedException(); // How do I solve this to make it like: http://msdn.microsoft.com/en-us/library/microsoft.xna.framework.vector2.normalize.aspx
    }

Note that I do NOT use the XNA framework.

Answer 1

public static PointF Normalize(this PointF A)
{
    float distance = Math.Sqrt(A.X * A.X + A.Y * A.Y);
    return new PointF(A.X / distance, A.Y / distance);
}

Also see the first paragraph here to learn what a normalized vector (unit vector) is and how you can calculate it.

Answer 2

public static PointF Normalize(this PointF A)
{
    float length = Math.Sqrt( A.X*A.X + A.Y*A.Y);
    return new PointF( A.X/length, A.Y/length);
}