let N;

let total;

​

let path = [];

​

function setup() {

​

  N = int(pow(2, order));

  total = N * N;

​

  createCanvas(512, 512)

  colorMode(HSB,360,255,255);

  background(0);

​

  for (let i = 0; i < total; i++) {

    path[i] = hilbert(i)

​

    let len = width / N;

    path[i].mult(len);

    path[i].add(len / 2, len / 2)

  }

​

}

​

​

​

function hilbert(i) {

​

  points = [createVector(0, 0),

    createVector(0, 1),

    createVector(1, 1),

    createVector(1, 0)

  ];

​

​

​

  let index = i & 3;

  let v = points[index];

​

  for (let j = 1; j < order; j++) {

​

    i = i >>> 2;

    index = i & 3;

    let len = pow(2,j);

​

    if (index == 0) {

      let temp = v.x;

      v.x = v.y;

      v.y = temp;

​

    } else if (index == 1) {

      v.y += len;

    } else if (index == 2) {

      v.x += len;

      v.y += len;

    } else if (index == 3) {

      let temp = len-1 - v.x;

      v.x = len-1 - v.y;

      v.y = temp;

      v.x += len;

    }

  }

  return v;

}

​

let counter = 0;

function draw() {

  background(0);

  stroke(255);

  strokeWeight(2);

  noFill();

  for (let i = 1; i < counter; i++) {

    let h = float(map(i,0,path.length,0,255));

    stroke(h,255,255);

    line(path[i].x, path[i].y,path[i-1].x, path[i-1].y);

  }

​

  counter+=10;

  if ( counter >= path.length) {

    counter=0;

  }

  // for (let i = 0; i < path.length; i++) {

  //   strokeWeight(4);

  //   point(path[i].x, path[i].y);

  //   strokeWeight(1);

  //   text(i, path[i].x + 5, path[i].y - 3);

  // }

​

​

}