Random Shape generator

Processing Coding Questions
6

Hey, I watched this video by Daniel Shiffman and copied the code and changed it a bit. Now I only have one problem I want to connect the start and the end node to create a “real” shape. Anyone have an idea?

Here is my code:

PVector[] cities;
int totalCities = 40;

void setup() {
  frameRate(30);
  fullScreen();
  //size(600, 600);
  cities = new PVector[totalCities];
  for (int i = 1; i < totalCities-1; i++) {
    PVector v = new PVector(random(width), random(height));
    cities[i] = v;
  }
  cities[0] = new PVector(10, 10);
  cities[totalCities-1] = new PVector(width-10, height-10);
  //cities[cities.length-1] = cities[0].copy();

  //arrayCopy(cities, bestEver);
}

void draw() {
  background(0);
  fill(255);
  for (int i = 0; i < cities.length; i++) {
    ellipse(cities[i].x, cities[i].y, 8, 8);
  }

  stroke(255);
  strokeWeight(1);
  noFill();
  beginShape();
  for (int i = 0; i < cities.length; i++) {
    vertex(cities[i].x, cities[i].y);
  }
  endShape();

  //stroke(255, 0, 255);
  //strokeWeight(4);
  //noFill();
  //beginShape();
  //for (int i = 0; i < cities.length; i++) {
  //  vertex(bestEver[i].x, bestEver[i].y);
  //}
  //endShape();





  for (int i = 0; i < cities.length-1; i++) {
    PVector a = cities[i];
    PVector b = cities[i+1];
    for (int j = i + 2; j < cities.length-1; j++) {
      PVector a2 = cities[j];
      PVector b2 = cities[j+1];
      if (lineLineCollision(a.x, a.y, b.x, b.y, a2.x, a2.y, b2.x, b2.y) == true) {
        swap(cities, i, j);
      }
    }
  }
}
//void mousePressed() {
//  int indexI = floor(random(cities.length));
//  int indexJ = floor(random(cities.length));
//  swap(cities, indexI, indexJ);
//}
void keyPressed() {
  setup();
}
void swap(PVector[] a, int i, int j) {
  PVector temp = a[i];
  a[i] = a[j];
  a[j] = temp;
}
boolean lineLineCollision(float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4) {

  // calculate the distance to intersection point
  float uA = ((x4-x3)*(y1-y3) - (y4-y3)*(x1-x3)) / ((y4-y3)*(x2-x1) - (x4-x3)*(y2-y1));
  float uB = ((x2-x1)*(y1-y3) - (y2-y1)*(x1-x3)) / ((y4-y3)*(x2-x1) - (x4-x3)*(y2-y1));

  // if uA and uB are between 0-1, lines are colliding
  if (uA >= 0 && uA <= 1 && uB >= 0 && uB <= 1) {

    // optionally, draw a circle where the lines meet
    //float intersectionX = x1 + (uA * (x2-x1));
    //float intersectionY = y1 + (uA * (y2-y1));
    //fill(255, 0, 0);
    //noStroke();
    //ellipse(intersectionX, intersectionY, 20, 20);

    return true;
  }
  return false;
}