// Gravitational Painting 3 John Clavin - June 20, 2016

var system_1;
var system_2;

var nLines = 96;

function setup() {
  createCanvas(1060, 540);
  background(140);
  fill(243);
  stroke(110);
  strokeWeight(3);
  rect(20, 20, 500, 500);
  rect(540, 20, 500, 500);
  system_1 = new System();
  system_2 = new System();
  
  for (var i = 0; i < nLines; i++) {
    var b = new Brush();
    system_1.addBrush(b)
  }
  for (var j = 0; j < nLines; j++) {
    system_1.assignBrushFriend(j, int(random(20, 22)));
  }
  
  for (var k = 0; k < nLines; k++) {
    b = new Brush();
    system_2.addBrush(b)
  }
  for (var l = 0; l < nLines; l++) {
    system_2.assignBrushFriend(l, int(random(20, 22)));
  }
}

function draw() {
  translate(20, 20);
  system_1.runSystem();
  translate(520, 0);
  system_2.runSystem();
  if (frameCount > 460) {
    translate(-540, -20);
    noFill();
    stroke(110);
    strokeWeight(4);
    rect(20, 20, 500, 500);
    rect(540, 20, 500, 500);
    noLoop();
  }
}

var System = function() {
  this.brushes = [];
  
  this.addBrush = function(b) {
    this.brushes.push(b);
  }
  
  this.assignBrushFriend = function(n, f) {
    this.brushes[n].friend = f;
    if(f == 20) {
      this.brushes[n].color = color(200, 0, 0, 112);  
    } else {
      this.brushes[n].color = color(30, 112);
    }
  }
  
  this.runSystem = function() {
    for (var i = 0; i < this.brushes.length; i++) {
      var bFriend = this.brushes[i].friend;
      var force = this.brushes[i].calculateAttraction(this.brushes[bFriend]);
      force.mult(1.8);
      this.brushes[i].applyForce(force);
      this.brushes[i].update();
      this.brushes[i].checkEdges();
      this.brushes[i].display();
    }
  }
}

var Brush = function() {
  this.color;
  var choice = int(random(4));
  if (choice === 0) {
    this.x = random(500);
    this.y = 0;
  } else if(choice == 1) {
    this.x = random(500);
    this.y = 500;
  } else if(choice == 2) {
    this.x = 0;
    this.y = random(500); 
  } else {
    this.x = 500;
    this.y = random(500); 
  }
  
  this.pos = createVector(this.x, this.y);
  this.vel = createVector(0, 0);
  this.acc = createVector(0, 0);
  this.friend = 0;
  this.edgeFlag = false;
  
  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.checkEdges = function() {
    if( this.pos.x < -1 || this.pos.x > 501) {
      this.edgeFlag = true;
    }
    if( this.pos.y < -1 || this.pos.y > 501) {
      this.edgeFlag = true;
    }
  }

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