let x1, y1, x2, y2, x3, y3;

// Position for mid-point between 3 points

let avgX, avgY;

// Diagonal of canvas

let diag;

​

// Which mode

let mode = 0;

​

function setup() {

  createCanvas(windowWidth, windowHeight);

  // Start out on a diagonal

  x1 = width * 0.25;

  y1 = height * 0.25;

  x2 = width * 0.75;

  y2 = height * 0.67;

  x3 = width / 2;

  y3 = height / 2;

​

  diag = sqrt(sq(width), sq(height));

  rectMode(CENTER);

  noStroke();

}

​

function draw() {

  background(0);

​

  // Find the avgX, avgY

  avgX = (x1 + x2 + x3) / 3;

  avgY = (y1 + y2 + y3) / 3;

​

​

  // Draw a boundary around the furthest point

  let d1 = dist(avgX, avgY, x1, y1);

  let d2 = dist(avgX, avgY, x2, y2);

  let d3 = dist(avgX, avgY, x3, y3);

​

  // Sort distances

  let ds = [d1, d2, d3];

  ds.sort(function(a, b) {

    return a - b;

  });

  // Use the shortest distance as the length of a side of the square

  let s = ds[mode] * 2;

​

  // Draw the rect (a square)

  fill('white');

  rect(avgX, avgY, s, s);

​

  fill('red');

  // Draw the positions

  ellipse(x1, y1, 10, 10);

  ellipse(x2, y2, 10, 10);

  ellipse(x3, y3, 10, 10);

  // Draw the average point

  //ellipse(avgX, avgY, 20, 20);

​

}

​

// Move the point closest to the mouse with the mouse

// if mouse is being dragged

function mouseDragged() {

  // Calculate distances of points from mouse

  let d1 = dist(mouseX, mouseY, x1, y1);

  let d2 = dist(mouseX, mouseY, x2, y2);

  let d3 = dist(mouseX, mouseY, x3, y3);

  // Store the distances in an array

  // Find the shortest distance

  // Record index number of shortest distance

  let ds = [d1, d2, d3];

  let low = diag;

  let lowIndex = -1;

  for (let d = 0; d < ds.length; d++) {

    if (ds[d] < low) {

      low = ds[d];

      lowIndex = d;

    }

  }

​

  // Set the position closest to mouse

  // to the mouse position

  if (lowIndex == 0) {

    x1 = mouseX;

    y1 = mouseY;

  } else if (lowIndex == 1) {

    x2 = mouseX;

    y2 = mouseY;

  } else {

    x3 = mouseX;

    y3 = mouseY;

  }

​

}

​

function keyPressed() {

  mode++;

  mode %= 3;

  console.log(mode);

}