// http://codingtra.in

// http://patreon.com/codingtrain

​

// QuadTree

// https://www.youtube.com/watch?v=z0YFFg_nBjw

​

// For more:

// https://github.com/CodingTrain/QuadTree

​

​

let particles = [];

​

function setup() {

  createCanvas(600, 400);

  for (let i = 0; i < 1000; i++) {

    particles[i] = new Particle(random(width), random(height));

  }

}

​

function draw() {

  background(0);

​

​

  let boundary = new Rectangle(300, 200, 600, 400);

  let qtree = new QuadTree(boundary, 4);

let checkedPairs = new Set();

​

  for (let p of particles) {

    let point = new Point(p.x, p.y, p);

    qtree.insert(point);

​

​

    p.move();

    p.render();

    p.setHighlight(false);

  }

​

  for (let p of particles) {

    let range = new Circle(p.x, p.y, p.r * 2);

    let points = qtree.query(range);

    for (let point of points) {

      let other = point.userData;

      // for (let other of particles) {

      if (p !== other && p.intersects(other)) {

        p.setHighlight(true);

      }

    }

  }

​

}

​