CA ca;
public int rows;
public int cols;
public int res;
float offset;

int[][] board;

void setup() {
  size(800, 800);
  frameRate(30);
  background(255);
  res = 1;
  rows = (int)(height/res);
  cols = (int)(width/res);
  offset = res/2;

  ca = new CA();

  board = new int[cols][rows];

  for (int x = 0; x < cols; x++) {
    for (int y = 0; y < rows; y++) {
      board[x][y] = (int)random(2);
    }
  }
}

void draw() {
  //background(255);

  //ca.display();
  //ca.generate();
  noStroke();
  for (int x = 0; x < cols; x+= 1) {
    for (int y = 0; y < rows; y+= 1) {
      if (board[x][y] == 1) fill(0);
      else fill(255);
      rect(x*res, y*res, res, res);
    }
  }

  computeNextGeneration();
}

void computeNextGeneration() {
  int[][] nextBoard = new int[cols][rows];

  for (int x = 1; x < cols-1; x++) {
    for (int y = 1; y < rows-1; y++) {
      int n = 0;
      for (int i = -1; i <= 1; i++) {
        for (int j =  -1; j <= 1; j++) {
          n += board[x+i][x+j];
        }
      }

      n-= board[x][y];

      if (board[x][y] == 1 && n < 2) nextBoard[x][y] = 0;
      else if (board[x][y] == 1 && n > 6) nextBoard[x][y] = 1;
      else if (board[x][y] == 0 && n == 6) nextBoard[x][y] = 1;
      else nextBoard[x][y] = board[x][y];
    }
  }

  board = nextBoard;
}

void mousePressed(){
  saveFrame("noise-####.png");
 setup();
}

class CA {

  int[] cells;
  int[] ruleset;

  int generation;

  CA() {
    cells = new int[cols];

    ruleset = new int[8];

    ruleset[0] = 0;
    ruleset[1] = 1;
    ruleset[2] = 0;
    ruleset[3] = 1;
    ruleset[4] = 1;
    ruleset[5] = 0;
    ruleset[6] = 1;
    ruleset[7] = 0;

    for (int i = 0; i < cells.length; i++) {
      cells[i] = (int)random(2);
    }
    cells[cells.length/2] = 1;

    generation = 0;
  }

  void generate() {
    int[] newcells = new int[cells.length];

    for (int i = 1; i < cells.length-1; i++) {
      int left = cells[i-1];
      int middle = cells[i];
      int right = cells[i+1];

      int newstate = rule(left, middle, right);

      newcells[i] = newstate;
    }

    cells = newcells;

    generation++;


    if(generation > width/res) generation = 0;
  }

  int rule(int l, int m, int r) {
    String s = ""+l+m+r;
    int index = Integer.parseInt(s, 2);

    return ruleset[index];
  }

  void display() {
    for (int i = 0; i < cells.length; i++) {

      if (cells[i] == 0) fill(255, 20);
      else fill(0, 20);
      noStroke();
      rect(i*res, generation*res, res, res);
    }
  }
}