private void Start()
{
// Cache transform
trans = transform;
// Cache & set up rigidbody
rb = GetComponent <Rigidbody>();
rb.drag = 0;
rb.useGravity = false;
rb.isKinematic = false;
// Bail out if we don't have an object to orbit around
if (orbitAround == null)
{
Debug.LogWarning("Satellite has no object to orbit around");
return;
}
// Update the ellipse with initial value
if (ellipse == null)
{
Reset();
}
ellipse.Update(orbitAround.position, transform.position, apsisDistance, circularOrbit);
// Calculate starting orbit state
orbitState = new OrbitState(startingAngle, this, ellipse);
// Position the orbiter
trans.position = ellipse.GetPosition(startingAngle, orbitAround.position);
// Add starting velocity
rb.AddForce(orbitState.velocity, ForceMode.VelocityChange);
StartCoroutine("Orbit");
}
// Update the state of the orbiter when its position along the ellipse changes
// Note: Make sure the ellipse is up to date before updating the orbit state
private void Update(float orbiterAngle, Orbiter orbiter, OrbitalEllipse ellipse)
{
this.orbiter = orbiter;
this.ellipse = ellipse;
this.normal = CalcNormal(orbiterAngle);
this.tangent = CalcTangent(normal);
this.position = ellipse.GetPosition(orbiterAngle, orbiter.orbitAround.position);
this.velocity = CalcVelocity(orbiter.orbitSpeed * orbiter.GravityConstant(), position, orbiter.orbitAround.position);
}