/* Simulation of a parallel computation, automaton-ish.  Each
cell updates based upon the immediate (not diagonal) neighbors
of its immediate neighbors, resulting in implicit communication
to 12 total cells, weighted. */

/* 25 possible cells filled.  Cells stays (or becomes) alive
between min and max */

int minimum = 8;
int maximum = 18;

/* Display variables */
int cellSize = 2;
int cellsX = 300;
int cellsY = 300;

/* The world */
boolean[][] grid = new boolean[cellsX][cellsY];

/* Our groups */
color black  = #BBBBBB;
color white  = #44CC44;

/* Click to start */
void setup() {
  background(white);
  noStroke();
  size(600, 600, P2D);
  seedGrid();
  colorGrid();
  noLoop();
}

void draw() {
  shuffle();
  colorGrid();
}

void mousePressed() {
  setup();
}

void keyPressed() {
  loop();
}

void seedGrid() {
  for(int x = 0; x < cellsX; x++) {
    for(int y = 0; y < cellsY; y++) {    
      int gridseed = (int)random(-1,2);
      if(gridseed == 0) {
        grid[x][y] = false;
      } else {
        grid[x][y] = true;
      }
    }
  }
}

void colorGrid() {
  for(int x = 0; x < cellsX; x++) {
    for(int y = 0; y < cellsY; y++) {
      if(grid[x][y] == false) {
        fill(black);
      } else {
        fill(white);
      }
      rect(x*cellSize,y*cellSize,cellSize,cellSize);  
    }
  }
}

void shuffle() {
  for(int x = 0; x < cellsX; x++) {
    for(int y = 0; y < cellsY; y++) {
      x = (int)random(0,cellsX);
      y = (int)random(0,cellsY);
      int trueCells = trueCells(x,y);
      if( trueCells > minimum && trueCells < maximum) {
        grid[x][y] = true;
      } else {
        grid[x][y] = false;
      }
    }
  }
}

int trueCells(int x, int y) {
  /* some short-cuts in this method */
  int trueCells = 0;
  if(grid[(x+cellsX-2)%cellsX][y]) { trueCells += 1; }
  if(grid[(x+cellsX-1)%cellsX][y]) { trueCells += 2; }
  if(grid[(x+1)%cellsX][y])        { trueCells += 2; }
  if(grid[(x+2)%cellsX][y])        { trueCells += 1; }
  if(grid[x][(y+cellsY-2)%cellsY]) { trueCells += 1; }
  if(grid[x][(y+cellsY-1)%cellsY]) { trueCells += 2; }
  if(grid[x][(y+1)%cellsY])        { trueCells += 2; }
  if(grid[x][(y+2)%cellsY])        { trueCells += 1; }
  if(grid[(x+cellsX-1)%cellsX][(y+cellsY-1)%cellsY])
                                   { trueCells += 2; }
  if(grid[(x+1)%cellsX][(y+1)%cellsY])
                                   { trueCells += 2; }
  if(grid[(x+1)%cellsX][(y+cellsY-1)%cellsY])
                                   { trueCells += 2; }
  if(grid[(x+cellsX-1)%cellsX][(y+1)%cellsY])
                                   { trueCells += 2; }
  return trueCells;
}