/// <summary>
/// Get orbit curve points without array allocation, if current orbit state is valid.
/// </summary>
/// <remarks>
/// Note: array allocation may sometimes occur, if specified array is null or lenght is not equal to target points count.
/// </remarks>
/// <param name="points">Resulting orbit curve array.</param>
/// <param name="pointsCount">Max orbit curve points count.</param>
/// <param name="origin">World position of attractor (focus of orbit).</param>
/// <param name="maxDistance">Max distance for orbit curve points.</param>
public void GetOrbitPointsNoAlloc(ref Vector3d[] points, int pointsCount, Vector3d origin, double maxDistance = 1000d)
{
if (pointsCount < 2)
{
points = new Vector3d[0];
return;
}
if (Eccentricity < 1)
{
if (points == null || points.Length != pointsCount)
{
points = new Vector3d[pointsCount];
}
if (ApoapsisDistance < maxDistance)
{
for (var i = 0; i < pointsCount; i++)
{
points[i] = GetFocalPositionAtEccentricAnomaly(i * Mathd.PI_2 / (pointsCount - 1d)) + origin;
}
}
else
{
var maxAngle = CelestialBodyUtils.CalcTrueAnomalyForDistance(maxDistance, Eccentricity, SemiMajorAxis);
for (int i = 0; i < pointsCount; i++)
{
points[i] = GetFocalPositionAtTrueAnomaly(-maxAngle + i * 2d * maxAngle / (pointsCount - 1)) + origin;
}
}
}
else
{
if (maxDistance < PeriapsisDistance)
{
points = new Vector3d[0];
return;
}
if (points == null || points.Length != pointsCount)
{
points = new Vector3d[pointsCount];
}
var maxAngle = CelestialBodyUtils.CalcTrueAnomalyForDistance(maxDistance, Eccentricity, SemiMajorAxis);
for (int i = 0; i < pointsCount; i++)
{
points[i] = GetFocalPositionAtTrueAnomaly(-maxAngle + i * 2d * maxAngle / (pointsCount - 1)) + origin;
}
}
}
public Vector3[] GetOrbitPoints(int pointsCount, Vector3 origin, float maxDistance = 1000f)
{
if (pointsCount < 2)
{
return(new Vector3[0]);
}
var result = new Vector3[pointsCount];
if (eccentricity < 1)
{
if (apoapsisDistance < maxDistance)
{
for (var i = 0; i < pointsCount; i++)
{
result[i] = (Vector3)GetFocalPositionAtEccentricAnomaly(i * Mathd.PI_2 / (pointsCount - 1d)) + origin;
}
}
else
{
var maxAngle = CelestialBodyUtils.CalcTrueAnomalyForDistance(maxDistance, eccentricity, semiMajorAxis);
for (int i = 0; i < pointsCount; i++)
{
result[i] = (Vector3)GetFocalPositionAtTrueAnomaly(-maxAngle + i * 2d * maxAngle / (pointsCount - 1)) + origin;
}
}
}
else
{
if (maxDistance < periapsisDistance)
{
return(new Vector3[0]);
}
var maxAngle = CelestialBodyUtils.CalcTrueAnomalyForDistance(maxDistance, eccentricity, semiMajorAxis);
for (int i = 0; i < pointsCount; i++)
{
result[i] = (Vector3)GetFocalPositionAtTrueAnomaly(-maxAngle + i * 2d * maxAngle / (pointsCount - 1)) + origin;
}
}
return(result);
}
