class Particle{
  
  PVector location;
  PVector velocity;
  PVector acceleration;
  float mass;

  Particle() {
    location = new PVector(random(-200, 200),random(-100,100),10);
    velocity = new PVector();
    acceleration = new PVector();
    mass = random(0.5,1.0);
  }

  void update() {
  velocity.add(acceleration);
  location.add(velocity);
  acceleration = new PVector();
  velocity.x = cos(noise(location.x*.02,location.y*.02, millis()*.0002)*TWO_PI); 
  velocity.y = sin(noise(location.x*.02,location.y*.02, millis()*.0002)*TWO_PI);
  }

  void render() {
    update();
    float cl = map(getVel().y, -0.9, 0.9, 99, 45);
    stroke(0, 100, 100, cl);
    strokeWeight(0.5f);
    line(location.x,location.y,location.z,location.x,location.y,location.z-20);
  }
  
  PVector getVel() { 
    return velocity; 
  }   
  
  void add_force(PVector force) {
    force.div(mass);  
    acceleration.add(force); 
  } 
  
  boolean pop() { 
    if (((location.x > 200) || (location.x < -200)) || ((location.y > 100) || (location.y < -100)) || ((location.z > 10) || (location.z < -10))){ 
      return true;
    }
    else return false;   
  }  
  
}

  import peasy.*;
PeasyCam pCamera;
ArrayList p = new ArrayList();
float d=127,f=0;
void setup()
{
  size(750, 450, P3D);
  colorMode(HSB,360, 100, 100);
  smooth();
  pCamera = new PeasyCam(this, 700);
  pCamera.setMinimumDistance(600);
  pCamera.setMaximumDistance(800);

  for(int i=0; i<6000; i++){ 
   p.add(new Particle());
  }
  noiseDetail(10, .2);
}

void draw()
{
  background(1, 0, 100);
  float e = cos(PI*(f+=1)/d);
  float em = map(e, -1, 1, -1.5, -0.5);
  pushMatrix();
  fill(200, 50, 40, 2);
  strokeWeight(0.3f);
  stroke(1, 0, 0, 10);
  box(400, 200, 20);
  popMatrix();
  for(int i = p.size()-1; i >= 0; i--){
    Particle part = (Particle) p.get(i);
    part.render();    
    PVector actualVel = part.getVel();
    PVector pickup = new PVector(0.2, em, 0);
    PVector attrito = PVector.mult(actualVel, 0.5); 
    part.add_force(pickup);   
    part.add_force(attrito);        
    if (part.pop()) {
        p.remove(i);
        p.add(new Particle());      
    }
  }
}