GravityCenterCalculator

/*
 * R e a d m e
 * -----------
 *
 * In this file you can include any instructions or other comments you want to have injected onto the
 * top of your final script. You can safely delete this file if you do not want any such comments.
 */

// cpa_time(): compute the time of CPA for two tracks
//    Input:  two tracks Tr1 and Tr2
//    Return: the time at which the two tracks are closest
public static double cpa_time(Vector3D Tr1_p, Vector3D Tr1_v, Vector3D Tr2_p, Vector3D Tr2_v)
{
    Vector3D dv = Tr1_v - Tr2_v;

    double dv2 = Vector3D.Dot(dv, dv);
    if (dv2 < 0.00000001)      // the  tracks are almost parallel
        return 0.0;             // any time is ok.  Use time 0.

    Vector3D w0 = Tr1_p - Tr2_p;
    double cpatime = -Vector3D.Dot(w0, dv) / dv2;

    return cpatime;             // time of CPA
}

public static string Vector2GPSString(string l, Vector3D v)
{
    //GPS: klassekatze #2:4186.55:17490.12:19153.15:#FFB775F1:
    return "GPS:" + l + ":" + v.X.ToString("0.00") + ":" + v.Y.ToString("0.00") + ":" + v.Z.ToString("0.00") + ":#FFB775F1:";
}

IMyShipController c = null;

public Program()
{
    c = (IMyShipController)GridTerminalSystem.GetBlockWithName("Cockpit");
}
Vector3D p1, p2 = Vector3D.Zero;
Vector3D g1, g2 = Vector3D.Zero;

public void Main(string argument, UpdateType updateSource)
{
    if (argument == "m")
    {
        if (p1 == Vector3D.Zero)
        {
            p1 = c.GetPosition();
            g1 = Vector3D.Normalize(c.GetNaturalGravity());
        }
        else if (p2 == Vector3D.Zero)
        {
            p2 = c.GetPosition();
            g2 = Vector3D.Normalize(c.GetNaturalGravity());
        }

        if (p2 != Vector3D.Zero)
        {
            double t = cpa_time(p1, g1, p2, g2);
            if (t != 0.0)
            {
                Vector3D center = p1 + (g1 * t);
                string o = t + "\n" + g1.ToString()+"\n"+g2.ToString()+"\n"+
                Vector2GPSString("pcenter", center);
                Me.CustomData = o;
                Echo(o);
            }
        }
    }
}