// The Coding Train / Daniel Shiffman

// https://thecodingtrain.com/CodingChallenges/162-self-avoiding-walk.html

// https://youtu.be/

​

// Basic: https://editor.p5js.org/codingtrain/sketches/2_4gyDD_9

// With Backtracking: https://editor.p5js.org/codingtrain/sketches/dRWS3A9nq

// 3D: https://editor.p5js.org/codingtrain/sketches/D0ONOlCDT

// With Bezier: https://editor.p5js.org/codingtrain/sketches/KFbX0NWgh

// With Recursion: https://editor.p5js.org/codingtrain/sketches/UPxBk1YiB

// Random Walk with Alpha: https://editor.p5js.org/codingtrain/sketches/IEw2RkDnJ

​

let grid;

let spacing = 5;

let cols, rows;

let path = [];

let spot;

​

function make2DArray(cols, rows) {

  let arr = new Array(cols);

  for (var i = 0; i < arr.length; i++) {

    arr[i] = new Array(rows);

  }

  return arr;

}

​

function setup() {

  createCanvas(400, 400);

  cols = floor(width / spacing);

  rows = floor(height / spacing);

  background(51);

  grid = make2DArray(cols, rows);

  for (let i = 0; i < cols; i++) {

    for (let j = 0; j < rows; j++) {

      grid[i][j] = new Spot(i, j);

    }

  }

  spot = grid[cols/2][rows/2];

  path.push(spot);

  spot.visited = true;

  // frameRate(1);

}

​

function isValid(i, j) {

  if (i < 0 || i >= cols || j < 0 || j >= rows) {

    return false;

  }

  return !grid[i][j].visited;

}

​

function draw() {

  background(0);

  translate(spacing * 0.5, spacing * 0.5);

​

  // for (let i = 0; i < 500000; i++) {

  spot = spot.nextSpot();

  if (!spot) {

    let stuck = path.pop();

    stuck.clear();

    spot = path[path.length - 1];

  } else {

    path.push(spot);

    spot.visited = true;

  }

​

  if (path.length === cols * rows) {

    console.log("Solved!");

    noLoop();

    // break;

  }

  //}

​

  stroke(255);

  strokeWeight(spacing * 0.25);

  noFill();

  beginShape();

  for (let spot of path) {

    vertex(spot.x, spot.y);

  }

  endShape();

​

  stroke(255);

  strokeWeight(spacing * 0.5);

  point(spot.x, spot.y);

}

​