/// <summary>
/// Returns an orbit representing the defined parameters.
/// </summary>
/// <param name="semiMajorAxis_AU">SemiMajorAxis of orbit in AU.</param>
/// <param name="eccentricity">Eccentricity of orbit.</param>
/// <param name="inclination">Inclination of orbit in degrees.</param>
/// <param name="longitudeOfAscendingNode">Longitude of ascending node in degrees.</param>
/// <param name="argumentOfPeriapsis">Argument of periapsis in degrees.</param>
/// <param name="meanAnomaly">Mean Anomaly in degrees.</param>
/// <param name="epoch">reference time for these orbital elements.</param>
public static OrbitDB FromAsteroidFormat([NotNull] Entity parent, double parentMass, double myMass, double semiMajorAxis_AU, double eccentricity, double inclination,
double longitudeOfAscendingNode, double argumentOfPeriapsis, double meanAnomaly, DateTime epoch)
{
if (parent == null)
{
throw new ArgumentNullException(nameof(parent));
}
double sma_m = Distance.AuToMt(semiMajorAxis_AU);
OrbitDB orbit = new OrbitDB(parent)
{
SemiMajorAxis = sma_m,
Eccentricity = eccentricity,
Inclination_Degrees = inclination,
LongitudeOfAscendingNode_Degrees = longitudeOfAscendingNode,
ArgumentOfPeriapsis_Degrees = argumentOfPeriapsis,
MeanAnomalyAtEpoch_Degrees = meanAnomaly,
Epoch = epoch,
_parentMass = parentMass,
_myMass = myMass
};
orbit.CalculateExtendedParameters();
return(orbit);
}
/// <summary>
/// Circular orbit from position.
/// </summary>
/// <param name="parent"></param>
/// <param name="obj"></param>
/// <param name="atDatetime"></param>
/// <returns></returns>
public static OrbitDB FromPosition(Entity parent, Entity obj, DateTime atDatetime)
{
var parpos = parent.GetDataBlob <PositionDB>();
var objPos = obj.GetDataBlob <PositionDB>();
var ralpos = objPos.AbsolutePosition_m - parpos.AbsolutePosition_m;
var r = ralpos.Length();
var i = Math.Atan2(r, ralpos.Z);
var m0 = Math.Atan2(ralpos.Y, ralpos.X);
var orbit = new OrbitDB(parent)
{
SemiMajorAxis = r,
Eccentricity = 0,
Inclination_Degrees = i,
LongitudeOfAscendingNode = 0,
ArgumentOfPeriapsis = 0,
MeanAnomalyAtEpoch = m0,
Epoch = atDatetime,
_parentMass = parent.GetDataBlob <MassVolumeDB>().Mass,
_myMass = obj.GetDataBlob <MassVolumeDB>().Mass
};
orbit.IsStationary = false;
orbit.CalculateExtendedParameters();
return(orbit);
}
/// <summary>
/// In Meters!
/// </summary>
/// <param name="parent"></param>
/// <param name="myMass"></param>
/// <param name="parentMass"></param>
/// <param name="sgp_m"></param>
/// <param name="position_m"></param>
/// <param name="velocity_m"></param>
/// <param name="atDateTime"></param>
/// <returns></returns>
/// <exception cref="Exception"></exception>
public static OrbitDB FromVector(Entity parent, double myMass, double parentMass, double sgp_m, Vector3 position_m, Vector3 velocity_m, DateTime atDateTime)
{
if (position_m.Length() > OrbitProcessor.GetSOI_AU(parent))
{
throw new Exception("Entity not in target SOI");
}
//var sgp = GameConstants.Science.GravitationalConstant * (myMass + parentMass) / 3.347928976e33;
var ke = OrbitMath.KeplerFromPositionAndVelocity(sgp_m, position_m, velocity_m, atDateTime);
OrbitDB orbit = new OrbitDB(parent)
{
SemiMajorAxis = ke.SemiMajorAxis,
Eccentricity = ke.Eccentricity,
Inclination = ke.Inclination,
LongitudeOfAscendingNode = ke.LoAN,
ArgumentOfPeriapsis = ke.AoP,
MeanAnomalyAtEpoch = ke.MeanAnomalyAtEpoch,
Epoch = atDateTime,
_parentMass = parent.GetDataBlob <MassVolumeDB>().Mass,
_myMass = myMass
};
orbit.CalculateExtendedParameters();
var pos = OrbitProcessor.GetAbsolutePosition_m(orbit, atDateTime);
return(orbit);
}
/// <summary>
/// In Meters
/// </summary>
/// <param name="parent"></param>
/// <param name="myMass"></param>
/// <param name="ke">in m</param>
/// <param name="atDateTime"></param>
/// <returns></returns>
public static OrbitDB FromKeplerElements(Entity parent, double myMass, KeplerElements ke, DateTime atDateTime)
{
OrbitDB orbit = new OrbitDB(parent)
{
SemiMajorAxis = ke.SemiMajorAxis,
Eccentricity = ke.Eccentricity,
Inclination = ke.Inclination,
LongitudeOfAscendingNode = ke.LoAN,
ArgumentOfPeriapsis = ke.AoP,
MeanAnomalyAtEpoch = ke.MeanAnomalyAtEpoch,
Epoch = atDateTime,
_parentMass = parent.GetDataBlob <MassVolumeDB>().Mass,
_myMass = myMass
};
orbit.IsStationary = false;
orbit.CalculateExtendedParameters();
return(orbit);
}
/// <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);
}
