কণা ব্যবস্থায় বল ব্যবহার

var Particle = function(position) {
  this.acceleration = new PVector(0, 0.05);
  this.velocity = new PVector(random(-1, 1), random(-1, 0));
  this.position = new PVector(position.x, position.y);
  this.timeToLive = 255.0;
};

Particle.prototype.update = function(){
  this.velocity.add(this.acceleration);
  this.position.add(this.velocity);
  this.timeToLive -= 2;
};

Particle.prototype.applyForce = function(force) {
  var f = force.get();
  f.div(this.mass);
  this.acceleration.add(f);
};

Particle.prototype.update = function() {
  this.velocity.add(this.acceleration);
  this.position.add(this.velocity);
  this.acceleration.mult(0);
  this.timeToLive -= 2.0;
};

draw = function() {
  background(168, 255, 156);
  particleSystem.addParticle();
  particleSystem.run();
};

draw = function() {
  background(168, 255, 156);
  particleSystem.applyForce(wind);
  particleSystem.addParticle();
  particleSystem.run();
};

ParticleSystem.prototype.applyForce = function(f){
  for(var i = 0; i < this.particles.length; i++){
    this.particles[i].applyForce(f);
  }
};

// একটি ধ্রুব ভেক্টর, যা শুরুতেই তৈরি করা হয়
var gravity = new PVector(0, 0.2);

ParticleSystem.prototype.applyGravity = function() {
    for(var i = 0; i < this.particles.length; i++) {
        var particleG = gravity.get();
        particleG.mult(this.particles[i].mass);
        this.particles[i].applyForce(particleG);
    }
};

var particleSystem = new ParticleSystem(new PVector(width/2, 50));
var repeller = new Repeller(width/2-20, height/2);
var gravity = new PVector(0, 0.1);

draw = function() {
  background(214, 255, 171);

  // সকল কণায় মহাকর্ষ বল প্রয়োগ
  particleSystem.applyForce(gravity);
  particleSystem.applyRepeller(repeller);
  repeller.display();
  particleSystem.addParticle();
  particleSystem.run();
};

var Repeller = function(x, y) {
  this.position = new PVector(x, y);
};

Repeller.prototype.display = function() {
  stroke(255);
  strokeWeight(2);
  fill(127);
  ellipse(this.position.x, this.position.y, 32, 32);
};

ParticleSystem.prototype.applyRepeller = function(r) {
  for(var i = 0; i < this.particles.length; i++){
    var p = this.particles[i];
    var force = r.calculateRepelForce(p);
    p.applyForce(force);
  }
};

Repeller.prototype.calculateRepelForce = function(p) {
  // Calculate vector for force between objects
  var dir = PVector.sub(this.position, p.position); 
  // Calculate distance between objects
  var dist = dir.mag();
  // Keep distance within a reasonable range
  dist = constrain(dist, 1, 100);    
  // Calculate repelling force,
  // inversely proportional to distance squared
  var force = -1 * this.power/ (dist * dist);     
  // Normalize direction vector
  // (discarding distance information)
  dir.normalize();
  // Calculate force vector: direction * magnitude
  dir.mult(force);                                  
  return dir;
};