// calulate all gravitational forces in game
// then will apply the force to the given object
public void ApplyGravityToObject(GameObject gameObject)
{
Vector2 netForce = new Vector2(0f, 0f);
Vector2 position = gameObject.position;
foreach (GameObject opposer in asteroids)
{
// find unit vector
Vector2 diffVect = opposer.position - position;
Vector2 unitVector;
if (diffVect.Length() == 0.0f) continue;
unitVector.X = diffVect.X / diffVect.Length();
unitVector.Y = diffVect.Y / diffVect.Length();
Vector2 currentForce;
currentForce.X = (opposer.mass / diffVect.LengthSquared()) * GRAVITATIONAL_CONSTANT * unitVector.X;
currentForce.Y = (opposer.mass / diffVect.LengthSquared()) * GRAVITATIONAL_CONSTANT * unitVector.Y;
netForce += currentForce;
}
netForce.X = netForce.X * gameObject.mass;
netForce.Y = netForce.Y * gameObject.mass;
gameObject.UpdateVelocityWithForce(netForce);
}
