/// <summary>
/// <see cref="UnityEngine.Debug.Log(object)"/> the OrbitData.
/// </summary>
/// <param name="inDegrees">If set to <c>true</c>, logs the angles in degrees; default (false) in radians.</param>
public void Log(bool inDegrees = false)
{
double _i = i;
double _Om = Om;
double _w = w;
double _M = M;
double _nu = nu;
double _E = E;
if (inDegrees)
{
_i *= OrbitUtils.Rad2Deg;
_Om *= OrbitUtils.Rad2Deg;
_w *= OrbitUtils.Rad2Deg;
_M *= OrbitUtils.Rad2Deg;
_nu *= OrbitUtils.Rad2Deg;
_E *= OrbitUtils.Rad2Deg;
}
Debug.LogFormat("EPOCH {0:F5}, Date {1}", epoch, OrbitUtils.JDN2CalendarString(epoch));
Debug.LogFormat(" A = {0:E5}, EC = {1:E5}", a, ecc);
Debug.LogFormat("IN = {0:E5}, OM = {1:E5}, W = {2:E5}", _i, _Om, _w);
Debug.LogFormat("MA = {0:E5}, TA = {1:E5}, E = {2:E5}", _M, _nu, _E);
Debug.LogFormat("r = ({0:E15}, {1:E15}, {2:E15}), v = ({3:E15}, {4:E5}, {5:E5})",
pos.x, pos.y, pos.z, vel.x, vel.y, vel.z);
}
static Vector3 GetVertexOfOrbitEllipse(double a, double ecc, double nu, double[,] T)
{
double E = OrbitUtils.TrueAnom2EccentricAnom(nu, ecc);
double rx = a * (Math.Cos(E) - ecc);
double ry = a * Math.Sqrt(1 - ecc * ecc) * Math.Sin(E);
return((Vector3)OrbitUtils.ApplyTransform(rx, ry, T));
}
/// <summary>
/// Updates the position and velocity of the body in its orbit based on
/// the current anomaly. Reference plane is the ecliptic plane (J2000).
/// </summary>
void UpdatePositionAndVelocity()
{
// Heliocentric coordinates in its orbital plane r'.
double rx = a * (Math.Cos(E) - ecc);
double ry = a * Math.Sqrt(1 - ecc * ecc) * Math.Sin(E);
// Heliocentric velocity in its orbital plane v'.
double cosE = Math.Cos(E);
double r = a * (1 - ecc * cosE);
double k = Math.Sqrt(mu * a) / r;
double vx = k * -Math.Sin(E);
double vy = k * Math.Sqrt(1 - ecc * ecc) * cosE;
double[,] T = OrbitUtils.GetTransformToEcliptic(i, Om, w);
pos = OrbitUtils.ApplyTransform(rx, ry, T);
vel = OrbitUtils.ApplyTransform(vx, vy, T);
}
/// <summary>
/// Steps the orbit by <paramref name="deltaTime"/>.
/// Recalculates the anomalies for the new deltaTime, then updates the
/// position and velocity at the new anomalies.
/// </summary>
/// <param name="deltaTime">Delta time [days].</param>
public void Step(double deltaTime)
{
// Recalculate anomalies M, E, ν (nu) for time t = t0 + deltaTime.
//M = M + (deltaTime * OrbitUtils.DAY2SEC) * Math.Sqrt(mu / (a * a * a));
M = M + (deltaTime * OrbitUtils.DAY2SEC) * N;
M = OrbitUtils.NormalizeAngle(M, 0.0, OrbitUtils.TwoPI);
E = OrbitUtils.SolveKeplerEqForEccentricAnom(ecc, M, 1e-10, 20);
nu = 2 * Math.Atan2(Math.Sqrt(1 + ecc) * Math.Sin(E / 2),
Math.Sqrt(1 - ecc) * Math.Cos(E / 2));
// Calculate the position and velocity for the new epoch.
UpdateStateFromElems();
// Update epoch to reflect the timestep.
epoch = epoch + deltaTime;
}
/// <summary>
/// Returns the a position
/// </summary>
/// <returns>The to ecliptic.</returns>
/// <param name="MA">The mean anomaly [rad].</param>
public Vector3d GetPositionFromMeanAnom(double MA)
{
double EA = OrbitUtils.MeanAnom2EccentricAnom(ecc, MA);
double xv = a * (Math.Cos(EA) - ecc);
double yv = a * Math.Sqrt(1.0 - ecc * ecc) * Math.Sin(EA);
double v = Math.Atan2(yv, xv); // True anomaly, nu
double r = Math.Sqrt(xv * xv + yv * yv); // Radius
// Precalculate and store trig terms
double sinOm = Math.Sin(Om);
double cosOm = Math.Cos(Om);
double sinNuW = Math.Sin(nu + w);
double cosNuW = Math.Cos(nu + w);
double cosI = Math.Cos(i);
double xh = cosOm * cosNuW - sinOm * sinNuW * cosI;
double yh = sinOm * cosNuW + cosOm * sinNuW * cosI;
double zh = sinNuW * Math.Sin(i);
return(new Vector3d(r * xh, r * yh, r * zh));
}
/// <summary>
/// Gets the points on orbit ellipse.
/// </summary>
/// <param name="vertices">Reference array storing the vertices of the ellipse.</param>
/// <param name="resolution">Number of vertices to draw ellipse.</param>
public void GetEllipseFromTrueAnom(ref Vector3[] vertices, int resolution)
{
if (resolution < 2)
{
vertices = new Vector3[0];
return;
}
//if (ecc < 1 && ecc >= 0)
if (vertices == null || vertices.Length != resolution)
{
vertices = new Vector3[resolution];
}
// Resolution as the angular distance (nu) between each vertex.
double nuResolution = OrbitUtils.TwoPI / resolution;
double[,] T = OrbitUtils.GetTransformToEcliptic(i, Om, w);
for (int i = 0; i < resolution; i++)
{
vertices[i] = GetVertexOfOrbitEllipse(a, ecc, i * nuResolution, T);
}
}
