let w, h;

let player;

let cells;

function setup() {

  numCells = 25;

  setSize();

  createCanvas(w, h);

  textAlign(CENTER,CENTER);

  textFont("Courier");

  textSize(cellSize);

  cells = [];

  for (let r = 0; r < numCells; r++) {

    cells[r] = [];

    for (let c = 0; c < numCells; c++) {

      cells[r][c] = {col: random(255)};

    }

  }

  player = {};

  player.r = int(random(0,numCells-1));

  player.c = int(random(0,numCells-1));

}

​

function draw() {

  background(220);

  for (let r = 0; r < numCells; r++) {

    for (let c = 0; c < numCells; c++) {

      fill(cells[r][c].col);

      rect(c*cellSize,r*cellSize,cellSize,cellSize);

    }

  }

  fill(color(255,0,255));

  text("@", player.c*cellSize+halfCellSize,player.r*cellSize+halfCellSize);

  frameRate(10);

}

​

function windowResized() {

  setSize(); 

  resizeCanvas(w, h);

}

​

function setSize() {

  w = windowWidth;

  h = windowHeight;

  if (w > h) w = h;

  else h = w;

  cellSize = w / numCells;

  halfCellSize = cellSize / 2;

  textSize(cellSize);

}