​

function setup() {

  createCanvas(400, 400);

  turret = new Turret(width/2, height/2)

}

​

function draw() {

  background(220);  

  turret.update(mouseX, mouseY)

  turret.render()

}

​

class Turret {

  constructor(x, y) {

    this.x = x

    this.y = y

    this.angle = 0

  }

  update(mx, my) {

    this.angle = atan2(my - this.y, mx - this.x)

  }

  render() {

    push();

    translate(this.x, this.y);

    rotate(this.angle);

    fill(153, 204, 0);

    ellipse(this.size / 4, 0, this.size / 2, this.size / 2);

    rect(20/4, 20/2, 20, 40)

    pop();

  }

}