// The Nature of Code

// The Coding Train / Daniel Shiffman

// https://youtu.be/DxFDgOYEoy8

// https://thecodingtrain.com/learning/nature-of-code/2.4-drag.html

// https://editor.p5js.org/codingtrain/sketches/5V8nSBOS

​

class Mover {

  constructor(x, y, m) {

    this.pos = createVector(x, y);

    this.vel = createVector(0, 0);

    this.acc = createVector(0, 0);

    this.mass = m;

    this.r = sqrt(this.mass) * 10;

  }

​

​

  drag(c) {

    // Direction of Drag

    let drag = this.vel.copy();

    drag.normalize();

    drag.mult(-1);

    let speedSq = this.vel.magSq();

    drag.setMag(c * speedSq);

    this.applyForce(drag);

  }

​

​

​

  applyForce(force) {

    let f = p5.Vector.div(force, this.mass);

    this.acc.add(f);

  }

​

​

  edges() {

    if (this.pos.y >= height - this.r) {

      this.pos.y = height - this.r;

      this.vel.y *= -1;

    }

​

    if (this.pos.x >= width - this.r) {

      this.pos.x = width - this.r;

      this.vel.x *= -1;

    } else if (this.pos.x <= this.r) {

      this.pos.x = this.r;

      this.vel.x *= -1;

    }

  }

​

​

  update() {

​

    // let mouse = createVector(mouseX, mouseY);

    // this.acc = p5.Vector.sub(mouse, this.pos);

    // this.acc.setMag(0.1);

​

    this.vel.add(this.acc);

    this.pos.add(this.vel);

    this.acc.set(0, 0);

  }

​

  show() {

    stroke(255);

    strokeWeight(2);

    fill(255, 100);

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

  }

}