public static Vector GravityForce(MaterialPoint b1, MaterialPoint b2, double G)
{
double forceAbs;
Vector forceOX;
if (b1.Coordinates == b2.Coordinates)
{
return(Vector.ZeroVector());
}
forceAbs = G * (b1.Mass * b2.Mass) / (Math.Pow(b1.DistanceTo(b2), 2));
forceOX = new Vector(forceAbs, 0);
forceOX = forceOX.RotateTo(b2.Coordinates - b1.Coordinates);
return(forceOX);
}
private void UpdateField()
{
Vector[] forces = new Vector[Bodies.Count];
Vector currForce, acceleration;
int i, j;
bool countingNeeded = true;
for (i = 0; i < Bodies.Count; i++)
{
forces[i] = Vector.ZeroVector();
}
for (i = 0; i < Bodies.Count; i++)
{
for (j = 0; j < Bodies.Count; j++)
{
if (i == j)
{
continue;
}
if (CollisionsType == CollisionType.InelasticCollisions)
{
/*Check if bodies collided*/
if (Bodies[i] is PhysicalBody && Bodies[j] is PhysicalBody)
{
if (Bodies[i].DistanceTo(Bodies[j]) < ((PhysicalBody)Bodies[i]).Diameter + ((PhysicalBody)Bodies[j]).Diameter)
{
MaterialPoint newBody = new PhysicalBody(
coordinates: Bodies[i].Coordinates,
mass: Bodies[i].Mass + Bodies[j].Mass,
/*Momentum conservation law*/
velocity: (Bodies[i].Velocity * Bodies[i].Mass + Bodies[j].Velocity * Bodies[j].Mass) / (Bodies[i].Mass + Bodies[j].Mass),
/*Sum of volumes*/
diameter: Math.Pow(Math.Pow(((PhysicalBody)Bodies[i]).Diameter, 3) + Math.Pow(((PhysicalBody)Bodies[j]).Diameter, 3), (double)1 / 3)
);
/*First must be deleted the last. In other cases this will cause an exception*/
BodyDeletedRaise(Math.Max(i, j));
BodyDeletedRaise(Math.Min(i, j));
Bodies.RemoveAt(Math.Max(i, j));
Bodies.RemoveAt(Math.Min(i, j));
BodyAddedRaise(newBody);
Bodies.Add(newBody);
countingNeeded = false;
}
}
}
else if (CollisionsType == CollisionType.ElasticCollisions)
{
/*Check if bodies collided*/
if (Bodies[i] is PhysicalBody && Bodies[j] is PhysicalBody)
{
if (Bodies[i].DistanceTo(Bodies[j]) < ((PhysicalBody)Bodies[i]).Diameter + ((PhysicalBody)Bodies[j]).Diameter)
{
double m1 = Bodies[i].Mass, m2 = Bodies[j].Mass;
Vector v1 = Bodies[i].Velocity, v2 = Bodies[j].Velocity;
/*Momentum conservation law*/
Bodies[i].Velocity = (m1 - m2) / (m1 + m2) * (v1 - v2) + v2;
Bodies[j].Velocity = (2 * m1 * v1) / (m1 + m2) + v2;
countingNeeded = false;
}
}
}
if (countingNeeded)
{
currForce = MaterialPoint.GravityForce(Bodies[i], Bodies[j], G);
forces[i] += currForce;
}
}
}
for (i = 0; i < Bodies.Count; i++)
{
acceleration = forces[i] / Bodies[i].Mass;
Bodies[i].Velocity = Bodies[i].Velocity + acceleration * DeltaTime;
Bodies[i].Coordinates += Bodies[i].Velocity * DeltaTime;
}
}
private void BodyAddedRaise(MaterialPoint body)
{
BodyAdded?.Invoke(body);
}
public double DistanceTo(MaterialPoint b2) => (Coordinates - b2.Coordinates).Length;
