var cell_size = 10;

var SIZE = 3000;



function setup() {

  createCanvas(SIZE, SIZE);

  stroke(0, 0, 0);



  numX = width / cell_size;

  numY = height / cell_size;



  cells = [];

  for (var i = 0; i < numX; i++) {

    cells[i] = [];

    for (var j = 0; j < numY; j++) {

      cells[i][j] = floor(random() * 5);

    }

  }



  initialize();

  generation = 0;



  drawCells();

}



function draw() {

  rule();

  generation++;

  drawCells();

}



var cells;

var numX;

var numY;

var generation;



function initialize() {



  for (var i = 0; i < numX; i++) {

    for (var j = 0; j < numY; j++) {

      cells[i][j] = floor(random() * 3);

    }

  }



}



function drawCells() {

  for (var i = 0; i < numX; i++) {

    for (var j = 0; j < numY; j++) {

      if (cells[i][j] == 1) fill(143, 61, 215);

      if (cells[i][j] == 0) fill(23, 28, 59);

      rect(i * cell_size, j * cell_size, cell_size, cell_size);

    }

  }

}



function rule() {

  var temp = [];



  for (var i = 0; i < numX; i++) {

    temp[i] = [];

    for (var j = 0; j < numX; j++) {

      temp[i][j] = 0;

    }

  }



  for (var i = 1; i < numX - 1; i++) {

    for (var j = 1; j < numY - 1; j++) {

      var neighbors = 0;



      if (cells[i - 1][j - 1] == 1) neighbors++;

      if (cells[i    ][j - 1] == 1) neighbors++;

      if (cells[i + 1][j - 1] == 1) neighbors++;

      if (cells[i - 1][j    ] == 1) neighbors++;

      if (cells[i + 1][j    ] == 1) neighbors++;

      if (cells[i - 1][j + 1] == 1) neighbors++;

      if (cells[i    ][j + 1] == 1) neighbors++;

      if (cells[i + 1][j + 1] == 1) neighbors++;



      if (cells[i][j] == 1) {

        if (neighbors == 0 || neighbors == 1) temp[i][j] = 0;

        if (neighbors == 2 || neighbors == 3) temp[i][j] = 1;

        if (neighbors >= 4) temp[i][j] = 0;

      }



      if (cells[i][j] == 0) {

        if (neighbors == 3) temp[i][j] = 1;

      }



    }

  }



  for (var i = 0; i < numX; i++) {

    for (var j = 0; j < numY; j++) {

      cells[i][j] = temp[i][j];

    }

  }



}