assignment5-planet-error2.js

var moon = [];
var earth;


function setup() {
  createCanvas(800, 500);
  background(0);
  for (var i = 0; i < 3; i++) {
    moon.push(new Particle(random(width), random(height), random(0.1, 3))); // (x,y,mass)
    moon[i].vel.y = random(0.5, 1.2);
  }
  earth = new Particle(width / 2, height / 2, 15); // (x,y,mass)
  

}


function draw() {
  background(0);
  // earth.pos.x = mouseX;
  // earth.pos.y = mouseY;

  for (var a = 0; a < moon.length; a++) {
    for (var b = 0; b < moon.length; b++) {
      moon[a].applyAttraction(moon[b]);
    }

    moon[a].applyAttraction(earth);
    moon[a].update();
    moon[a].display();
  }

  earth.update();
  earth.display();
}
"use strict";

class Particle {
  constructor(x, y, m) {
    this.pos = createVector(x, y);
    this.vel = createVector(0, 0);
    this.acc = createVector(0, 0);
    
    this.mass = m;
    this.rad = 2 * this.mass ;
  }
  applyForce(f) {
    f.div(this.mass);
    this.acc.add(f);
  }
  applyAttraction(other) {
    var force = p5.Vector.sub(other.pos, this.pos);
    force.mult(0.005);
    this.acc.add(force);
  }
  update() {
    this.vel.add(this.acc); // vel = vel + acc;
    this.pos.add(this.vel); // pos = pos + vel;
    this.acc.mult(0); // acceleration has to be reset after being applied! ***
  }
  display() {
    push();
    translate(this.pos.x, this.pos.y);
    stroke(255);
    fill(255, 100);
    ellipse(0, 0, this.rad * 2, this.rad * 2);
    pop();
  }
}