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Particle.pde
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Particle.pde
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static int _lastParticleId = 0;
public class Particle
{
int _id; // Unique id for each particle
PVector _s; // Position (m)
PVector _v; // Velocity (m/s)
PVector _a; // Acceleration (m/(s*s))
PVector _F; // Force (N)
float _m; // Mass (kg)
boolean _clamped; // If true, the particle will not move
Particle(PVector s, PVector v, float m, boolean clamped)
{
_id = _lastParticleId++;
_s = s.copy();
_v = v.copy();
_m = m;
_clamped = clamped;
_a = new PVector(0.0, 0.0, 0.0);
_F = new PVector(0.0, 0.0, 0.0);
}
void update(float simStep)
{
if (_clamped)
return;
updateForce();
// Simplectic Euler:
// v(t+h) = v(t) + h*a(s(t),v(t))
// s(t+h) = s(t) + h*v(t+h)
_a = PVector.div(_F, _m);
_v.add(PVector.mult(_a, simStep));
_s.add(PVector.mult(_v, simStep));
_F.set(0.0, 0.0, 0.0);
}
int getId()
{
return _id;
}
PVector getPosition()
{
return _s;
}
void setPosition(PVector s)
{
_s = s.copy();
_a.set(0.0,0.0,0.0);
_F.set(0.0,0.0,0.0);
}
void setVelocity(PVector v)
{
_v = v.copy();
}
void updateForce()
{
PVector weigthForce = PVector.mult(G, _m);
_F.add(weigthForce);
}
void addExternalForce(PVector F)
{
_F.add(F);
}
}