// Vallado Algorithm 10, p118
// (generic, will work for Ellipse as well, provided special cases are handled)
// Not used yet.
private void SetInitialPosition(NBody nbody)
{
// phase is in
float denom = 1 + ecc * Mathf.Cos(phase_nu);
Vector3 r_pqw = new Vector3(p * Mathf.Cos(phase_nu) / denom, p * Mathf.Sin(phase_nu) / denom, 0);
r_initial_phy = r_pqw.magnitude;
Vector3 r = hyper_orientation * r_pqw;
// orbit position is WRT center. Could be adding dynamically to an object in motion, so need current position.
Vector3 centerPos = Vector3.zero;
// used by widgets - so need to get explcitly
centerNbody = OrbitUtils.GetCenterNbody(this.transform, centerObject);
if (centerNbody.engineRef != null)
{
centerPos = GravityEngine.Instance().GetPhysicsPosition(centerNbody);
}
else
{
// setup - not yet added to GE
centerPos = centerNbody.initialPhysPosition;
}
nbody.initialPhysPosition = r + centerPos;
}
/// <summary>
/// Sets the initial position based on the orbit parameters. Used in the init phase to set the NBody in the
/// correct position in the scene before handing control GE.
/// </summary>
public void SetInitialPosition(NBody nbody)
{
float phaseRad = phase * Mathf.Deg2Rad;
// position object using true anomoly (angle from focus)
float r = a_scaled * (1f - ecc * ecc) / (1f + ecc * Mathf.Cos(phaseRad));
Vector3 pos = new Vector3(r * Mathf.Cos(phaseRad), r * Mathf.Sin(phaseRad), 0);
// move from XY plane to the orbital plane
Vector3 new_p = ellipse_orientation * pos;
// orbit position is WRT center. Could be adding dynamically to an object in motion, so need current position.
Vector3 centerPos = Vector3.zero;
// used by widgets - so need to get explcitly
centerNbody = OrbitUtils.GetCenterNbody(transform, centerObject);
if (centerNbody.engineRef != null)
{
centerPos = GravityEngine.Instance().GetPhysicsPosition(centerNbody);
}
else
{
// setup - not yet added to GE
centerPos = centerNbody.initialPhysPosition;
}
nbody.initialPhysPosition = new_p + centerPos;
}
/// <summary>
/// Init the hyperbola, verify a center body is present and determine orientation.
/// </summary>
public void Init()
{
CalcOrbitParams();
centerNbody = OrbitUtils.GetCenterNbody(transform, centerObject);
CalculateRotation();
NBody nbody = GetComponent <NBody>();
// particle ring would not have an NBody
if (nbody != null)
{
SetInitialPosition(nbody);
}
}
/// <summary>
/// Init the ellipse, verify a center body is present, determine orientation and update transform.
/// </summary>
public void Init()
{
// mode determines if user wants to define wrt to A or P. Determine other quantity
if (paramBy == ParamBy.AXIS_A)
{
p = a * (1 - ecc);
}
else if (paramBy == ParamBy.CLOSEST_P)
{
a = p / (1 - ecc);
}
centerNbody = OrbitUtils.GetCenterNbody(transform, centerObject);
CalculateRotation();
NBody nbody = GetComponent <NBody>();
// particle ring would not have an NBody
if (nbody != null)
{
SetInitialPosition(nbody);
}
}
