/// <summary>
/// Calculates the attraction force between two connected nodes, using the specified spring length.
/// </summary>
/// <param name="a">The node that the force is acting on.</param>
/// <param name="b">The node creating the force.</param>
/// <param name="springLength">The length of the spring, in pixels.</param>
/// <returns>A Vector representing the attraction force.</returns>
private Vector3D CalcAttractionForce(double springLength, double attractionConstant)
{
if (StartNode == EndNode)
{
return(new Vector3D(0, 0, 0));
}
var proximity = Math.Max(StartNode.GetDistanceToNode(EndNode), 0);
//var proximity = CalcDistance(a, b);
// Hooke's Law: F = -kx
var force = attractionConstant * (proximity - springLength);
//var force = ATTRACTION_CONSTANT * (proximity - springLength);
//var angle = GetBearingAngle(a, b);
//var angle = Math.Atan((b.Y - a.Y) / (b.X - a.X));
//return new Vector(force * Math.Cos(angle), force * Math.Sin(angle));
var vector = EndNode.Pos - StartNode.Pos;
if (vector.Length > 0)
{
vector.Normalize();
}
return(vector * force);
}
