​

var current=[];

var previous=[];

var rows;

var cols;

var cellsize=1;

var lowest;

var newlowest;

var highest;

var newhighest;

​

function setup() {

  createCanvas(800, 800);

  //frameRate(1);

  cols=width/cellsize;

  rows=height/cellsize;

  for(var i=0; i<cols*rows; i++)

  {

  current.push(floor(random(0,0)));

  previous.push(0);

  }

  current[ind((width/cellsize)/2,(height/cellsize)/2)]=100000;

  lowest=ind((width/cellsize)/2, (height/cellsize)/2);

  highest=lowest+1;

}

​

function draw() {

  background(220);

  show();

  for(var i=0; i<100; i++)

      {

      topple();

      }

}

​

function topple(){

// x = index % width

// y = index / width   

var x;

var y;

//previous=current;

for (var i=lowest; i<highest; i++)

{

previous[i]=current[i];  

}

​

//for(var i=0; i<previous.length; i++)

  for(var i=lowest; i<highest; i++)

    {

    x=(i%(width/cellsize));

    y=floor(i/(height/cellsize));

  //if((x>0) && (x<width/cellsize) && (y>0) && (y<height/cellsize))

    {

    if(previous[i]>3)

    {

    //console.log(x,y);

    current[i]=(current[i]-4);

    if(y>0)

    current[ind(y-1,x)]++;

    if(y<=height/cellsize)

    current[ind(y+1,x)]++;

    if(x>0)

    current[ind(y,x-1)]++;

    if(x<width/cellsize)

    current[ind(y,x+1)]++; 

    if(ind(y-1,x) < ind(x-1,y) && ind(y-1,x)<lowest)

    {

    newlowest=ind(y-1,x);

    }

    else if(ind(x-1,y) < lowest)

    {

    newlowest=ind(x-1,y);  

    }

    if(ind(y+1,x) > ind(y,x+1) && ind(y+1,x)>highest)

    {

    newhighest=ind(y+1,x);

    }

    else if(ind(y, x+1) > highest)

    {

    newhighest=ind(y, x+1); 

    }

    }

    }

    lowest=newlowest;

    highest=newhighest;

    }

}

​

function touchStarted()

{

var column=floor(mouseX/cellsize);

var row=floor(mouseY/cellsize);

//console.log(column, row);

​

current[ind(column, row)]+=0;

}

​

​

function ind(r, c)    // Returns Array index given a row/ col

{

var arrind=0;

arrind=r * (width/cellsize) + c;

return arrind;  

}

​

​

function show()

{

var col;

  var ind=0;

  for(var i=0; i<rows; i++)

  {

  for(var j=0; j<cols; j++)

    {

  switch (current[ind])

  {

    case 0: col= 'black';

    break;

    case 1: col= 'blue';

    break;

    case 2: col= 'green';

    break;

    default: col='red';

  }

    ind++;

    fill(col);

    stroke(col);

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

    }

  }

}