Game of life

The Conway game of life is a brilliant cellular automate.

It have got simple rules:

We count neighbours of cell

• If there is zero or one — cell dies
• If there are more than three — cell dies
• If cell is already dead and have exact three neighbours — it resurrect

Here is an implementation. I made just born cells blue and added randomly spawning cells for more action. Look!

let field = [], swapField = [];
for(let i = 0; i < h; i++){
  field[i] = [];
  swapField[i] = [];
  for(let j = 0; j < w; j++){
    field[i][j] = i%j%8 === 1;
    swapField[i][j] = 0;
  }
}
px.frameRate = 10;
let colors = [0x000000, 0xFFFFFF, 0x0088bb, 0x00FF00];

const countNeighbours = (x, y) => {
  let i, j, count = 0;
  for(i = -1; i < 2; i++)
    for(j = -1; j < 2; j++)
      if(i !== 0 || j !== 0)
        count += field[(y+i+h)%h][(x+j+w)%w] ? 1:0;
      
  return count;
};

const update = () => {  
  let x, y, neighbours;
  
  for(x = 0; x < w; x++)
    for(y = 0; y < h; y++)
      point(x,y, colors[field[y][x]]);
  
  for(x = 0; x < w; x++)
      for(y = 0; y < h; y++){
        
      neighbours = countNeighbours(x, y);
      
      if(field[y][x] !== 0){
        // Any live cell        
        // with fewer than two live neighbours dies
        swapField[y][x] = neighbours < 2 ? 0 :
          // with more than three live neighbours dies
          neighbours > 3 ? 0 : 1;
      }else{
        // Any dead cell with exactly three live neighbours becomes a live cell
        swapField[y][x] = neighbours === 3 ? 2 : 0;
      }
    }
  
  // selfborn cells
  for(x = 0; x < 20;x++)
    rand(115) === 1 && (swapField[rand(h)][rand(w)] = 3);
  
  [field, swapField] = [swapField, field]; 
}

Pulsar for the icon

I want to make a beautiful icon for this article, so I've looked through the list of known pulsars and find one that attracts me

px.frameRate = 6
let field = [], swapField = [];
for(let i = 0; i < h; i++){
    field[i] = [];
    swapField[i] = [];
    for(let j = 0; j < w; j++){
        field[i][j] = false;//i%j%8 === 1;
        swapField[i][j] = 0;
    }
}

const spriteSheet = px.spriteSheet('/img/gameOfLifeIcon.png', 48, 48);
spriteSheet.onload(function(){
    var sprite = spriteSheet.get(0,0);

    for(var x = 0; x < spriteSheet.fullWidth; x++)
        for(var y = 0; y < spriteSheet.fullWidth; y++)
            field[y][x] = sprite.getPoint(x,y) === 0 ? 1 : 0;

    draw();
});

let colors = [0x0A2938, 0xFFFFFF, 0xAaC9F8, 0x00FF00];

const countNeighbours = (x, y) => {
    let i, j, count = 0;
    for(i = -1; i < 2; i++)
        for(j = -1; j < 2; j++)
            if(i !== 0 || j !== 0)
                count += field[(y+i+h)%h][(x+j+w)%w] ? 1:0;

    return count;
};
const draw = () => {
    let x, y, neighbours;

    for(x = 0; x < w; x++)
        for(y = 0; y < h; y++)
            point(x,y, colors[field[y][x]]);
}
const update = () => {
    draw();
    let x, y, neighbours;

    for(x = 0; x < w; x++)
        for(y = 0; y < h; y++){

            neighbours = countNeighbours(x, y);

            if(field[y][x] !== 0){
                // Any live cell
                // with fewer than two live neighbours dies
                swapField[y][x] = neighbours < 2 ? 0 :
                    // with more than three live neighbours dies
                    neighbours > 3 ? 0 : 1;
            }else{
                // Any dead cell with exactly three live neighbours becomes a live cell
                swapField[y][x] = neighbours === 3 ? 2 : 0;
            }
        }

    [field, swapField] = [swapField, field];
}