/// <summary>
/// A direction interpolated between the two given directions.
/// </summary>
/// <param name="slon">Start longitude.</param>
/// <param name="slat">Start latitude.</param>
/// <param name="elon">End longitude.</param>
/// <param name="elat">End latitude.</param>
/// <param name="t">Interpolation.</param>
/// <param name="lon">Output longitude.</param>
/// <param name="lat">Output latitude.</param>
public virtual void InterpolateDirection(double slon, double slat, double elon, double elat, double t, ref double lon, ref double lat)
{
var s = new Vector3d(Math.Cos(slon) * Math.Cos(slat), Math.Sin(slon) * Math.Cos(slat), Math.Sin(slat));
var e = new Vector3d(Math.Cos(elon) * Math.Cos(elat), Math.Sin(elon) * Math.Cos(elat), Math.Sin(elat));
var v = (s * (1.0 - t) + e * t).Normalized();
lat = Functions.Safe_Asin(v.z);
lon = Math.Atan2(v.y, v.x);
}
public override void Move(Vector3d oldp, Vector3d p, double speed)
{
var oldPosition = oldp.Normalized();
var position = p.Normalized();
var oldlat = Functions.Safe_Asin(oldPosition.z);
var oldlon = Math.Atan2(oldPosition.y, oldPosition.x);
var lat = Functions.Safe_Asin(position.z);
var lon = Math.Atan2(position.y, position.x);
base.position.X -= (lon - oldlon) * speed * Math.Max(1.0, worldPosition.Magnitude() - Radius);
base.position.Y -= (lat - oldlat) * speed * Math.Max(1.0, worldPosition.Magnitude() - Radius);
}
public override void MoveForward(double distance)
{
// NOTE : co - x; so - y; ca - z; sa - w;
var oa = CalculatelongitudeLatitudeVector(position.X, position.Y);
var po = new Vector3d(oa.x * oa.z, oa.y * oa.z, oa.w) * Radius;
var px = new Vector3d(-oa.y, oa.x, 0.0);
var py = new Vector3d(-oa.x * oa.w, -oa.y * oa.w, oa.z);
var pd = (po - px * Math.Sin(position.Phi) * distance + py * Math.Cos(position.Phi) * distance).Normalized();
position.X = Math.Atan2(pd.y, pd.x);
position.Y = Functions.Safe_Asin(pd.z);
}