//public ParticleSpring makeOrUpdateSpring(int ID, Particle a, Particle b, double restLength, double springConstant, double damping)
//{
// bool found = false;
// for (int i = 0; i < springs.Count(); ++i)
// {
// if (ID != null && (springs[i].ID() != null))
// {
// if (ID == springs[i].ID())
// {
// found = true;
// return springs[i];
// }
// }
// }
// if (found == false)
// {
// ParticleSpring s = new ParticleSpring(ID++, a, b, restLength, springConstant, damping);
// springs.Add(s);
// return s;
// }
// return null;
//}
public void applyForces()
{
maxResidualForce = -1000000000.0;
maxNodalVelocity = -1000000000.0;
for (int i = 0; i < particles.Count(); ++i)
{
//if (!isFaceConstrained)
//{
particles[i].addForce(gravity);
//}
particles[i].addForce(particles[i].getVelocity() * -drag);
maxNodalVelocity = Math.Max(maxNodalVelocity, particles[i].getVelocity().GetLength());
}
//test whether we are converged according to the threshold criteria
//make sure the simulation has a couple of steps computed so we don't
//bail at time step 0 when the structure hasn't started moving yet.
if (maxNodalVelocity < threshold && stepCount > 10)
{
converged = true;
}
//F=kd, calculate the maximum residual force in any member
for (int i = 0; i < springs.Count(); i++)
{
ParticleSpring f = springs[i];
f.apply();
maxResidualForce = Math.Max(maxResidualForce, f.getResidualForce());
}
/*
* if (isFaceConstrained && constraintFace != null)
* {
* for (int i = 0; i < particles.Count(); ++i)
* {
* //get the component of force that is tangent
* //to the surface at the point
* IntersectionResult ir = constraintFace.Project(particles[i].getPosition());
* if (ir != null)
* {
* XYZ n = constraintFace.ComputeNormal(ir.UVPoint);
* n = n.Normalize();
* XYZ force = particles[i].getForce();
* //XYZ normalForce = new XYZ(force.X * n.X, force.Y * n.Y, force.Z * n.Z);
* double normalForce = force.DotProduct(n);
* //XYZ normalForce2 = new XYZ(normalForce.X * n.X, normalForce.Y * n.Y, normalForce.Z * n.Z);
* XYZ normalForce2 = normalForce * n;
* particles[i].clearForce();
* particles[i].addForce(force - normalForce2);
* }
* }
* }
*/
}
