/// <summary>
/// Creates on Orbit at current location from a given velocity
/// </summary>
/// <returns>The Orbit Does not attach the OrbitDB to the entity!</returns>
/// <param name="parent">Parent.</param>
/// <param name="entity">Entity.</param>
/// <param name="velocityAU">Velocity.</param>
public static OrbitDB FromVector(Entity parent, Entity entity, Vector3 velocityAU, DateTime atDateTime)
{
var parentMass = parent.GetDataBlob <MassVolumeDB>().Mass;
var myMass = entity.GetDataBlob <MassVolumeDB>().Mass;
var epoch1 = parent.Manager.ManagerSubpulses.StarSysDateTime; //getting epoch from here is incorrect as the local datetime doesn't change till after the subpulse.
var parentPos = OrbitProcessor.GetAbsolutePosition_AU(parent.GetDataBlob <OrbitDB>(), atDateTime); //need to use the parent position at the epoch
var posdb = entity.GetDataBlob <PositionDB>();
posdb.SetParent(parent);
var ralitivePos = posdb.RelativePosition_AU;//entity.GetDataBlob<PositionDB>().AbsolutePosition_AU - parentPos;
if (ralitivePos.Length() > OrbitProcessor.GetSOI(parent))
{
throw new Exception("Entity not in target SOI");
}
var sgp = GameConstants.Science.GravitationalConstant * (myMass + parentMass) / 3.347928976e33;
var ke = OrbitMath.KeplerFromPositionAndVelocity(sgp, ralitivePos, velocityAU, atDateTime);
var epoch = atDateTime;// - TimeSpan.FromSeconds(ke.Epoch); //ke.Epoch is seconds from periapsis.
OrbitDB orbit = new OrbitDB(parent, parentMass, myMass,
Math.Abs(ke.SemiMajorAxis),
ke.Eccentricity,
Angle.ToDegrees(ke.Inclination),
Angle.ToDegrees(ke.LoAN),
Angle.ToDegrees(ke.AoP),
Angle.ToDegrees(ke.MeanAnomalyAtEpoch),
epoch);
var pos = OrbitProcessor.GetPosition_AU(orbit, atDateTime);
var d = Distance.AuToKm(pos - ralitivePos).Length();
if (d > 1)
{
var e = new Event(atDateTime, "Positional difference of " + d + "Km when creating orbit from velocity");
e.Entity = entity;
e.SystemGuid = entity.Manager.ManagerGuid;
e.EventType = EventType.Opps;
//e.Faction = entity.FactionOwner;
StaticRefLib.EventLog.AddEvent(e);
//other info:
var keta = Angle.ToDegrees(ke.TrueAnomalyAtEpoch);
var obta = Angle.ToDegrees(OrbitProcessor.GetTrueAnomaly(orbit, atDateTime));
var tadif = Angle.ToDegrees(Angle.DifferenceBetweenRadians(keta, obta));
var pos1 = OrbitProcessor.GetPosition_AU(orbit, atDateTime);
var pos2 = OrbitProcessor.GetPosition_AU(orbit, ke.TrueAnomalyAtEpoch);
var d2 = Distance.AuToKm(pos1 - pos2).Length();
}
return(orbit);
}
/// <summary>
/// 2d vector
/// </summary>
/// <returns>The orbital vector ralitive to the parent</returns>
/// <param name="orbit">Orbit.</param>
/// <param name="atDateTime">At date time.</param>
public static Vector2 InstantaneousOrbitalVelocityVector(OrbitDB orbit, DateTime atDateTime)
{
var position = GetPosition_AU(orbit, atDateTime);
var sma = orbit.SemiMajorAxis;
if (orbit.GravitationalParameter == 0 || sma == 0)
{
return(new Vector2()); //so we're not returning NaN;
}
var sgp = orbit.GravitationalParameterAU;
double e = orbit.Eccentricity;
double trueAnomaly = OrbitProcessor.GetTrueAnomaly(orbit, atDateTime);
(double speed, double angle)polarvector = InstantaneousOrbitalVelocityPolarCoordinate(orbit, atDateTime);
var v = new Vector2()
{
Y = Math.Sin(polarvector.angle) * polarvector.speed,
X = Math.Cos(polarvector.angle) * polarvector.speed
};
return(v);
//return OrbitMath.InstantaneousOrbitalVelocityVector(sgp, position, sma, e, trueAnomaly);
}
/// <summary>
/// Creates on Orbit at current location from a given velocity
/// </summary>
/// <returns>The Orbit Does not attach the OrbitDB to the entity!</returns>
/// <param name="parent">Parent. must have massdb</param>
/// <param name="entity">Entity. must have massdb</param>
/// <param name="velocity_m">Velocity in meters.</param>
public static OrbitDB FromVelocity_m(Entity parent, Entity entity, Vector3 velocity_m, DateTime atDateTime)
{
var parentMass = parent.GetDataBlob <MassVolumeDB>().Mass;
var myMass = entity.GetDataBlob <MassVolumeDB>().Mass;
//var epoch1 = parent.Manager.ManagerSubpulses.StarSysDateTime; //getting epoch from here is incorrect as the local datetime doesn't change till after the subpulse.
//var parentPos = OrbitProcessor.GetAbsolutePosition_AU(parent.GetDataBlob<OrbitDB>(), atDateTime); //need to use the parent position at the epoch
var posdb = entity.GetDataBlob <PositionDB>();
posdb.SetParent(parent);
var ralitivePos = posdb.RelativePosition_m;//entity.GetDataBlob<PositionDB>().AbsolutePosition_AU - parentPos;
if (ralitivePos.Length() > OrbitProcessor.GetSOI_m(parent))
{
throw new Exception("Entity not in target SOI");
}
//var sgp = GameConstants.Science.GravitationalConstant * (myMass + parentMass) / 3.347928976e33;
var sgp_m = GMath.StandardGravitationalParameter(myMass + parentMass);
var ke_m = OrbitMath.KeplerFromPositionAndVelocity(sgp_m, ralitivePos, velocity_m, atDateTime);
OrbitDB orbit = new OrbitDB(parent)
{
SemiMajorAxis = ke_m.SemiMajorAxis,
Eccentricity = ke_m.Eccentricity,
Inclination = ke_m.Inclination,
LongitudeOfAscendingNode = ke_m.LoAN,
ArgumentOfPeriapsis = ke_m.AoP,
MeanAnomalyAtEpoch = ke_m.MeanAnomalyAtEpoch,
Epoch = atDateTime,
_parentMass = parentMass,
_myMass = myMass
};
orbit.CalculateExtendedParameters();
var pos = OrbitProcessor.GetPosition_m(orbit, atDateTime);
var d = (pos - ralitivePos).Length();
if (d > 1)
{
var e = new Event(atDateTime, "Positional difference of " + Stringify.Distance(d) + " when creating orbit from velocity");
e.Entity = entity;
e.SystemGuid = entity.Manager.ManagerGuid;
e.EventType = EventType.Opps;
//e.Faction = entity.FactionOwner;
StaticRefLib.EventLog.AddEvent(e);
//other info:
var keta = Angle.ToDegrees(ke_m.TrueAnomalyAtEpoch);
var obta = Angle.ToDegrees(OrbitProcessor.GetTrueAnomaly(orbit, atDateTime));
var tadif = Angle.ToDegrees(Angle.DifferenceBetweenRadians(keta, obta));
var pos1 = OrbitProcessor.GetPosition_m(orbit, atDateTime);
var pos2 = OrbitProcessor.GetPosition_m(orbit, ke_m.TrueAnomalyAtEpoch);
var d2 = (pos1 - pos2).Length();
}
return(orbit);
}
