#include <SPI.h>
#include <Adafruit_GFX.h>
#include <Adafruit_ST7735.h>
#include <Adafruit_seesaw.h>
#include <Adafruit_TFTShield18.h>

Adafruit_TFTShield18 ss;

const int w = 20;

const int h = 16;

const int initialPopulation = 70;

byte board[2][w][h];

byte g = 0;

#define SD_CS    4

#define TFT_CS  10

#define TFT_DC   8

#define TFT_RST  -1

Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);

void setup(void) {

ss.begin();

ss.tftReset();

tft.initR(INITR_GREENTAB);

tft.fillScreen(0x0000);

  tft.setRotation(3);

  seedRandomGeneration();

  Serial.begin(9600);

  for (int32_t i=TFTSHIELD_BACKLIGHT_OFF; i<TFTSHIELD_BACKLIGHT_ON; i+=100) {

    ss.setBacklight(i);

    delay(1);
  }
}

void seedRandomGeneration()

{

  randomSeed(analogRead(A1));

  for (byte i=0; i < initialPopulation; i++)

  {

    int x = random(w);

    int y = random(h);

    board[g][x][y] = 1;

  }

}

void displayBoard()

{

  tft.fillScreen(0x0000);

  for (int x = 0; x < w; x++)

  {

    for (int y = 0; y < h; y++)

    {

      if (board[g][x][y])

      {

       tft.fillRect(x * 8, y * 8, 8, 8, ST7735_BLUE);

      }

    }

  }

}

void loop()

{

  if (analogRead(A3) < 512)

  {

    displayBoard();

    updateGeneration();

    g = !g;

  }

  delay(7000);

}

void updateGeneration()

{

  for (int x = 0; x < w; x++)

  {

    for (int y = 0; y < h; y++)

    {

      board[!g][x][y] = updateCell(x, y);

    }

  }

}

byte updateCell(int x, int y)

{

  int n = numNeighbors(x, y);

  if (board[g][x][y] == 1)

  {

    if (n < 2) return 0;

    else if (n == 2 || n == 3) return 1;

    else if (n > 3) return 0;

  }

  else

  {

    return (n == 3);

  }

}

int numNeighbors(int x, int y)

{

  int n = 0;

  for (int dx = -1; dx <= 1; dx++)

  {

    for (int dy = -1; dy <= 1; dy++)

    {

      int x1 = x + dx;

      int y1 = y + dy;

      boolean middle = (dx == 0 && dy == 0);

      if (!middle && x1 > 0 && x1 < w && y1 > 0 && y1 < h)

      {

        n += board[g][x1][y1];

      }

    }

  }

  Serial.print(n);

  return n;

}