x: -1,

  y: -1,

};

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  background(220, 20, 120);

  noLoop();

}

​

function draw() {}

​

function mouseClicked() {

  if (rectStart.x == -1 || rectStart.y == -1) {

    rectStart.x = mouseX;

    rectStart.y = mouseY;

  } else {

    let rectEndX = mouseX;

    let rectEndY = mouseY;

    let rW = rectEndX - rectStart.x;

    let rH = rectEndY - rectStart.y;

​

    rect(rectStart.x, rectStart.y, rW, rH);

    rectStart.x = -1;

    rectStart.y = -1;

  }

}

​