public void Set()
{
if (parent.ActiveText != this.name.Text && parent.Active != -1)
{
var elements = new Structures.OrbitalElements()
{
semilatusrectum = SLRScale.Value * AU,
eccentricity = EScale.Value,
inclination = IncScale.Value * deg,
ascendingNodeLongitude = ANLScale.Value * deg,
periapsisArgument = PAScale.Value * deg,
trueAnomaly = TAScale.Value * deg
};
body = new Structures.Body(menu.new_bodies.FirstOrDefault(b => b.body.name == parent.ActiveText).body, elements);
}
body.name = this.name.Text;
body.stdGrav = Math.Pow(Math.E, MassScale.Value) * G * 1e22;
body.radius = RadiusScale.Value * 1e3;
body.color = new Vector3(RScale.Value, GScale.Value, BScale.Value);
}
} // paramaterless constructor for serialisation
public Body(Body parent, OrbitalElements elements)
{
// First check the values are reasonable. If parent == null it is assumed that
// position and velocity are set explicitly, and this constructor is not used
if (parent == null)
{
return;
}
this.parent = parent;
if (elements.eccentricity < 0 ||
elements.semilatusrectum < 0 ||
elements.inclination < 0 ||
elements.inclination > Math.PI ||
elements.ascendingNodeLongitude < 0 ||
elements.ascendingNodeLongitude >= 2 * Math.PI ||
elements.periapsisArgument < 0 ||
elements.periapsisArgument >= 2 * Math.PI ||
elements.trueAnomaly < 0 ||
elements.trueAnomaly >= 2 * Math.PI
)
{
// Throw an exception if the arguments are out of bounds
throw new ArgumentException();
}
// working in perifocal coordinates (periapsis along the x axis, orbit in the x,y plane):
double mag_peri_radius = elements.semilatusrectum / (1 + elements.eccentricity * Math.Cos(elements.trueAnomaly));
Vector3 peri_radius = mag_peri_radius * new Vector3(Math.Cos(elements.trueAnomaly), Math.Sin(elements.trueAnomaly), 0);
Vector3 peri_velocity = Math.Sqrt(parent.stdGrav / elements.semilatusrectum)
* new Vector3(
-Math.Sin(elements.trueAnomaly),
Math.Cos(elements.trueAnomaly) + elements.eccentricity,
0
);
// useful constants to setup transformation matrix
var sini = Math.Sin(elements.inclination); // i <- inclination
var cosi = Math.Cos(elements.inclination);
var sino = Math.Sin(elements.ascendingNodeLongitude); // capital omega <- longitude of ascending node
var coso = Math.Cos(elements.ascendingNodeLongitude);
var sinw = Math.Sin(elements.periapsisArgument); // omega <- argument of periapsis
var cosw = Math.Cos(elements.periapsisArgument);
// Transform perifocal coordinates to i,j,k coordinates
Matrix3 transform = new Matrix3(
new Vector3(
coso * cosw - sino * sinw * cosi,
-coso * sinw - sino * cosw * cosi,
sino * sini
),
new Vector3(
sino * cosw + coso * sinw * cosi,
-sino * sinw + coso * cosw * cosi,
-coso * sini
),
new Vector3(
sinw * sini,
cosw * sini,
cosi
)
);
// add the parent's position and velocity since that could be orbiting something too
this.position = transform * peri_radius + parent.position;
this.velocity = transform * peri_velocity + parent.velocity;
}
public static bool BodyTest()
{
var sun = new Body {
stdGrav = 1.3271440019e20,
radius = 6.95e8
};
var elem = new OrbitalElements()
{
semilatusrectum = 3.2 * AU,
eccentricity = 0.7,
inclination = 1.2,
ascendingNodeLongitude = 0.1,
periapsisArgument = 4.3,
trueAnomaly = 3.7
};
Body sun2 = (Body)sun.Clone();
sun2.position += new Vector3(3, 2, 6);
sun2.velocity += new Vector3(1, 5, 3);
var e1 = new Body(sun, elem);
var e2 = new Body(sun2, elem);
e2.position -= new Vector3(3, 2, 6);
e2.velocity -= new Vector3(1, 5, 3);
if (e1.position != e2.position || e1.velocity != e2.velocity)
{
Console.WriteLine("Parent r/v not considered");
return(false);
}
for (double i = 0; i < Math.PI; i += 0.2)
{
for (double j = 0; j < 2 * Math.PI; j += 0.2)
{
for (double k = 0; k < 2 * Math.PI; k += 0.2)
{
for (double l = 0; l < 2 * Math.PI; l += 0.2)
{
for (double m = 0; l < 1; l += 0.1)
{
var earthElements = new OrbitalElements()
{
semilatusrectum = 1 * AU,
eccentricity = m,
inclination = i,
ascendingNodeLongitude = j,
periapsisArgument = k,
trueAnomaly = l
};
var earth = new Body(sun, earthElements)
{
stdGrav = 3.986004419e14,
radius = 6.371e6,
color = new Vector3(0, 0.2, 0.8),
};
if (m == 0)
{
if (!(Math.Abs(Vector3.Magnitude(earth.velocity) - 3e4) < 1e3))
{
Console.WriteLine($"{i},{j},{k},{l},{earth.velocity}");
return(false);
}
else if (!(Math.Abs(Vector3.Magnitude(earth.position) - 1 * AU) < 1e-4))
{
Console.WriteLine($"{i},{j},{k},{l},{Vector3.Magnitude(earth.position)/AU}");
return(false);
}
}
var earthElements2 = new OrbitalElements(earth.position, earth.velocity, sun.stdGrav);
foreach (Tuple <string, double, double> t in new List <Tuple <string, double, double> >()
{
new Tuple <string, double, double>("l", earthElements.ascendingNodeLongitude, earthElements2.ascendingNodeLongitude),
new Tuple <string, double, double>("e", earthElements.eccentricity, earthElements2.eccentricity),
new Tuple <string, double, double>("i", earthElements.inclination, earthElements2.inclination),
new Tuple <string, double, double>("w", earthElements.periapsisArgument, earthElements2.periapsisArgument),
new Tuple <string, double, double>("p", earthElements.semilatusrectum, earthElements2.semilatusrectum),
new Tuple <string, double, double>("v", earthElements.trueAnomaly, earthElements2.trueAnomaly),
})
{
if ((t.Item2 - t.Item3) / t.Item2 > 1e-6)
{
if (t.Item1 == "l" && i == 0 ||
(t.Item1 == "w" || t.Item1 == "v") && m == 0)
{
// They are undefined, don't worry
continue;
}
Console.WriteLine($"Orbital element test failed: {t.Item1}, {t.Item2}, {t.Item3}, {((t.Item2 - t.Item3)/t.Item2)*100}%");
return(false);
}
}
}
}
}
}
}
var elemx = new OrbitalElements()
{
inclination = 2 * Math.PI,
ascendingNodeLongitude = 7.5 * Math.PI,
trueAnomaly = 27 * Math.PI,
periapsisArgument = 3.75 * Math.PI
};
if (
elemx.inclination > 1e-10 ||
(elemx.ascendingNodeLongitude - (1.5 * Math.PI)) / (1.5 * Math.PI) > 1e-10 ||
(elemx.trueAnomaly - Math.PI) / Math.PI > 1e-10 ||
(elemx.periapsisArgument - 1.75 * Math.PI) / (1.75 * Math.PI) > 1e-10
)
{
Console.WriteLine("Implicit angle readjustment failed");
Console.WriteLine(elemx.trueAnomaly / Math.PI);
}
return(true);
}
