// The Nature of Code

// The Coding Train / Daniel Shiffman

// https://youtu.be/EpgB3cNhKPM

// https://thecodingtrain.com/learning/nature-of-code/2.5-gravitational-attraction.html

// https://editor.p5js.org/codingtrain/sketches/MkLraatd

​

class Attractor {

  constructor(x,y,m,p) {

    this.pos = createVector(x,y);

    this.mass = m;

    this.r = sqrt(this.mass)*2;

    this.p = p;

  }

  attract(mover) {

    let force = p5.Vector.sub(this.pos, mover.pos);

    let distanceSq = constrain(force.magSq(), 100, 1000);

    let G = 5;

    let strength = G * (this.mass * mover.mass) / distanceSq;

    force.setMag(strength * this.p);

    mover.applyForce(force);

  }

  show() {

    noStroke();

    if (this.p === 1) {

      fill(255,0, 100);

    } 

    if (this.p === -1) {

      fill(0, 255, 100);

    }

    ellipse(this.pos.x, this.pos.y, this.r*2);    

  }

}