// Calculates and returns the gravitational force between two physics objects this tick
public Vector3 CalculateGravitationalForce(PhysicsObjectPair pair)
{
//Obtain Direction Vector
Vector3 pos1 = pair.O1.rb.position; //OPTIMISATION NOTE: These together cause 2x Rigidbody AND 2x Collider Syncs
Vector3 pos2 = pair.O2.rb.position;
Vector3 dir = new Vector3(pos1.x - pos2.x, pos1.y - pos2.y, pos1.z - pos2.z);
//Obtain Distance, return if 0
float distSqr = dir.x * dir.x + dir.y * dir.y + dir.z * dir.z;
if (distSqr == 0.0f)
{
return(Vector3.zero);
}
//Calculate Magnitude of force
float forceMagnitude = G * (pair.O1.rb.mass * pair.O2.rb.mass) / distSqr;
// Compare to current largest force for both objects
ForceExerter current_max;
// 1
if (!strongest_force.TryGetValue(pair.O1.ID, out current_max) || forceMagnitude > current_max.magnitude)
{
strongest_force[pair.O1.ID] = new ForceExerter(pair.O2.ID, forceMagnitude);
}
// 2
if (!strongest_force.TryGetValue(pair.O2.ID, out current_max) || forceMagnitude > current_max.magnitude)
{
strongest_force[pair.O2.ID] = new ForceExerter(pair.O1.ID, forceMagnitude);
}
//Calculate force
float dirMag = Mathf.Sqrt(distSqr);
Vector3 force = new Vector3(dir.x / dirMag, dir.y / dirMag, dir.z / dirMag) * forceMagnitude;
return(force);
}
// Adds the given physics object to the physics engine
// Registers and stores all possible pairs ahead of simulation
// This is called whenever a new physics object becomes enabled and active.
public void AddObject(PhysicsObject physicsObject)
{
// If pairs list does not exist, create it
if (ObjectPairs == null)
{
ObjectPairs = new List <PhysicsObjectPair>();
}
foreach (KeyValuePair <int, PhysicsObject> obj in PhysicsObject.physicsObjects)
{
//For every other object
if (obj.Value != physicsObject)
{
// Creat new pair
PhysicsObjectPair pair = new PhysicsObjectPair();
pair.O1 = physicsObject;
pair.O2 = obj.Value;
//Check if list already contains pair
bool alreadyInList = false;
foreach (PhysicsObjectPair objectPair in ObjectPairs.ToList())
{
//If pair already exists
if ((objectPair.O1 == pair.O1 && objectPair.O2 == pair.O2) ||
(objectPair.O2 == pair.O1 && objectPair.O1 == pair.O2))
{
alreadyInList = true;
}
}
//If pair not in list, add pair
if (!alreadyInList)
{
ObjectPairs.Add(pair);
}
}
}
}
Vector3[] PredictOrbit(PhysicsObject _strongestObject, uint steps)
{
try
{
Vector3[] positions = new Vector3[steps];
PhysicsObjectPair pair = new PhysicsObjectPair();
pair.O1 = this;
pair.O2 = _strongestObject;
// Calculate Orbital Period for this
//float period = (2.0f * Mathf.PI) * Mathf.Sqrt( Mathf.Pow(Vector3.Distance(pair.O1.transform.position, pair.O2.transform.position),3.0f) / G * ( pair.O1.rb.mass + pair.O2.rb.mass) );
Vector3 position1 = this.transform.position;
Vector3 position2 = _strongestObject.transform.position;
Vector3 velocity1 = this.rb.velocity - _strongestObject.rb.velocity;
//Vector3 velocity2 = _strongestObject.rb.velocity;
//Vector3 velocity2 = -velocity1;
Vector3 velocity2 = Vector3.zero;
//Vector3 velocity2 = _strongestObject.rb.velocity - this.rb.velocity;
float mass1 = this.rb.mass;
float mass2 = _strongestObject.rb.mass;
// Note, this is flawed as it assumes circular orbit
float period = (Mathf.PI * 2.0f) * Vector3.Distance(pair.O1.transform.position, pair.O2.transform.position) /
velocity1.magnitude;
float timestep = period / steps;
for (int i = 0; i < steps; i++)
{
positions[i] = position1;
// Calculate force
Vector3 force = new Vector3();
//Obtain Direction Vector
Vector3 dir = position1 - position2;
//Obtain Distance, return if 0
float dist = dir.magnitude;
if (dist == 0)
{
force = Vector3.zero;
}
//Calculate Magnitude of force
float magnitude = PhysicsEngine.G * (mass1 * mass2) / Mathf.Pow(dist, 2);
force = dir.normalized * magnitude;
// Calculate accelerations
Vector3 a1 = -force / mass1;
Vector3 a2 = force / mass2;
// Update positions
position1 += velocity1 * timestep + 0.5f * a1 * timestep * timestep;
position2 += velocity2 * timestep + 0.5f * a2 * timestep * timestep;
// Update velocities
velocity1 += a1 * timestep;
velocity2 += a2 * timestep;
}
return(positions);
}
catch
{
lineRenderer.positionCount = 0;
return(default);
