const GRIDSIZE = 32;

const GENCOUNT = GRIDSIZE;

​

const BOXSIZE = SZ/GRIDSIZE;

​

let currentWorld;

​

function setup() {

  createCanvas(SZ,SZ);

  currentWorld = makeFreshWorld(.5);

}

​

function mousePressed(){

  currentWorld = makeFreshWorld(map(mouseY,0,height,0,1));

}

​

function draw() {

  background(220);

  paintWorld2D(currentWorld);

  currentWorld = nextWorldState(currentWorld);

}

​

function nextWorldState(oldworld) {

  const newworld = []; 

  for(let x = 0; x < GRIDSIZE; x++){

    newworld[x] = [];

    for(let y = 0; y < GRIDSIZE; y++){

      if(oldworld[x][y]){ //was alive, stay alive with two or three neightbors

        const count = getNeighborCount(oldworld,x,y);        

        newworld[x][y] = (count == 2 || count == 3);        

      } else { //is dead, but will be alive 

        newworld[x][y] = getNeighborCount(oldworld,x,y) == 3;        

      }

    }

  }

  return newworld;

}

​

​

function getNeighborCount(world, x, y) { 

  return world[(x + 1) % GRIDSIZE][y] + 

    world[x][(y + 1) % GRIDSIZE] + 

    world[(x + GRIDSIZE - 1) % GRIDSIZE][y] + 

    world[x][(y + GRIDSIZE - 1) % GRIDSIZE] + 

    world[(x + 1) % GRIDSIZE][(y + 1) % GRIDSIZE] + 

    world[(x + GRIDSIZE - 1) % GRIDSIZE][(y + 1) % GRIDSIZE] + 

    world[(x + GRIDSIZE - 1) % GRIDSIZE][(y + GRIDSIZE - 1) % GRIDSIZE] + 

    world[(x + 1) % GRIDSIZE][(y + GRIDSIZE - 1) % GRIDSIZE]; 

} 

​

​

​

function cloneWorld(oldworld) {

  const world = []; 

  for(let x = 0; x < GRIDSIZE; x++){

    world[x] = [];

    for(let y = 0; y < GRIDSIZE; y++){

        world[x][y] = oldworld[x][y];

    }

  }

  return world;

}

​

function makeFreshWorld(prob){

  const world = []; 

  for(let x = 0; x < GRIDSIZE; x++){

    world[x] = [];

    for(let y = 0; y < GRIDSIZE; y++){

        world[x][y] = (random() > prob) ;

    }

  }

  return world;

}

function paintWorld2D(world){

  for(let x = 0; x < GRIDSIZE; x++){

    for(let y = 0; y < GRIDSIZE; y++){

        if(world[x][y]){

           rect(x * BOXSIZE, y * BOXSIZE, BOXSIZE, BOXSIZE); 

        }

    }

  }

}