let n = 28;

let w;

let start

let current

let previous

let velocity

let d = 3

let diverted = false

​

function getNeighbors(position) {  

  let neighbors = [];

  neighbors.push(p5.Vector.sub(position, createVector(1, 1)))

  neighbors.push(p5.Vector.sub(position, createVector(1, 0)))

  neighbors.push(p5.Vector.sub(position, createVector(1, -1)))

  neighbors.push(p5.Vector.sub(position, createVector(0, -1)))

  neighbors.push(p5.Vector.sub(position, createVector(-1, -1)))

  neighbors.push(p5.Vector.sub(position, createVector(-1, 0)))

  neighbors.push(p5.Vector.sub(position, createVector(-1, 1)))

  neighbors.push(p5.Vector.sub(position, createVector(0, 1)))

  return neighbors;

}

​

function isNeighborOfVelocity(current, neighbor, velocity) {

  print(velocity.x, velocity.y)

  let next = current.copy().add(velocity);

  let nextNeighbors = getNeighbors(next.copy());

  for (let n of nextNeighbors) {

    if (n.x === neighbor.x && n.y === neighbor.y && matrix[n.x][n.y] !== 1 && matrix[neighbor.x][neighbor.y] !== 1) {

      return true;

    }

  }

  return false;

}

​

function setup() {

  createCanvas(500, 500);

  w = width/n;

  start = createVector(15, 10);

  velocity = createVector(0, 0);

  for (let i = 0; i < n; i++) {

    matrix[i] = []

    for (let j = 0; j < n; j++) {

      matrix[i][j] = 0

    }

  }

}

​

function draw() {

  background(255);

  frameRate(10);

  let next = current

  if (!current) {

    current = start

    matrix[current.x][current.y] = 1

  }

  if (previous && !diverted) {

    velocity = current.copy().sub(previous)

  }

  let choices = [];

  let neighbors = getNeighbors(current)

  for (let neighbor of neighbors) {

    if (isNeighborOfVelocity(current, neighbor, velocity)) {

       choices.push(neighbor);

    }

  }

  print("Choices:", choices.length);

  let temp = random(choices)

  print(temp)

  if (temp) {

    if (temp.x == start.x && temp.y == start.y) {

      noLoop();

    }

​

    if (temp.x < d || temp.x > n - d) {

      velocity = createVector(velocity.x * -1, velocity.y)

      diverted = true

    } else if (temp.y < d || temp.y > n - d) {

      velocity = createVector(velocity.x, velocity.y * -1)

      diverted = true

    } else {

      next = temp;

      diverted = false

    }

​

    previous = current.copy();

    current = next

​

    if (current) {

       matrix[current.x][current.y] = 1

    } 

  }

  for (let i = 0; i < n; i++) {

    for (let j = 0; j < n; j++) {

      stroke(0)

      strokeWeight(1)

      if (matrix[i][j] == 0) fill(255)

      else fill(0, 0, 255)

      rect(i * w, j * w, w, w)

    }

  }

}

​