// Gravitational Painting 1 John Clavin - June 15, 2016

var system_1;
var system_2;

var nLines = 30;

function setup() {
  createCanvas(1080, 540);
  background(245);
  system_1 = new System();
  system_2 = new System();
  
  for (var i = 0; i < nLines; i++) {
    var m = new Mover();
    system_1.addMover(m)
  }
  for (var j = 0; j < nLines; j++) {
    system_1.assignMoverFriend(j, int(random(nLines)));
  }
  
  for (var k = 0; k < nLines; k++) {
    m = new Mover();
    system_2.addMover(m)
  }
  for (var l = 0; l < nLines; l++) {
    system_2.assignMoverFriend(l, int(random(nLines)));
  }
}

function draw() {
  translate(25, 0);
  system_1.runSystem();
  translate(555, 0);
  system_2.runSystem();
  if (frameCount > 500) {
    noLoop();
  }
}

var System = function() {
  this.movers = [];
  
  this.addMover = function(m) {
    this.movers.push(m);
  }
  
  this.assignMoverFriend = function(n, f) {
    this.movers[n].friend = f;
  }
  
  this.runSystem = function() {
    for (var i = 0; i < this.movers.length; i++) {
      var mFriend = this.movers[i].friend;
      var force = this.movers[i].calculateAttraction(this.movers[mFriend]);
      force.mult(1.8);
      this.movers[i].applyForce(force);
      this.movers[i].update();
      this.movers[i].display();
    }
  }
}

var Mover = function() {
  this.color = color(random(220), random(220), random(220), 116);
  if (random(100) < 50) {
    this.x = random(width/2 - 40);
    this.y = 0;
  } else {
    this.x = random(width/2 - 40);
    this.y = height;
  }
  this.pos = createVector(this.x, this.y);
  this.vel = createVector(0, 0);
  this.acc = createVector(0, 0);
  this.friend = 0;
  
  this.calculateAttraction = function(p) {
    var force = p5.Vector.sub(p.pos, this.pos);
    force.normalize();
    return force;
  }

  this.applyForce = function(force) {
    this.acc.add(force);
  }

  this.update = function() {
    this.vel.add(this.acc);
    this.pos.add(this.vel);
    this.acc.mult(0);
    this.vel.mult(0);
  }

  this.display = function() {
    strokeWeight(3);
    stroke(this.color);
    point(this.pos.x, this.pos.y);
  }
}