Snake for Arduino Uno with 128x64 LCD

/*
 Name:      Snake.ino
 Created:   12/29/2016 5:15:15 AM
 Author:    beefviper
*/

// Include U8g2 library for JHD529M1-12864F (ST7920) 128X64 monochrome LCD display
#include <U8g2lib.h>

// u8g2 LCD configuration line: _1 (single page) _6800 (comm mode) _R2 (180rotate), 8 data lines, 3 control lines
U8G2_ST7920_128X64_1_6800 u8g2(U8G2_R2, 8, 9, 10, 11, 4, 5, 6, 7, /*enable=*/ 18 /* A4 */, /*cs=*/ U8X8_PIN_NONE, /*dc/rs=*/ 17 /* A3 */, /*reset=*/ 15 /* A1 */);  // Remember to set R/W to 0

// Pin Assignments
const int xAxisPin    = 16;
const int yAxisPin    = 19;
const int buttonPin   =  2;
const int speakerPin  =  3;
const int floatingPin = 14;

// Hardware Constants
const int screenWidth  = 128;
const int screenHeight =  64;

// Joystick Variables
int joyX = 0;
int joyY = 0;
int joyB = 0;

// Game Variables
const int  frameSkip     =  1;
int        frameLimit    = frameSkip;
const int  maxLength     = 250;
const int  screenScale   =  4;
const int  screenColumns = screenWidth / screenScale;
const int  screenRows    = screenHeight / screenScale;
bool       buttonState   = false;
bool       gameOver      = true;
bool       firstGame     = true;
int        score         =  0;

class D2Point {
    public:
        int x;
        int y;
};

class Snake {
public:
    Snake();
    ~Snake();

    int velocityX;
    int velocityY;
    int length;
    D2Point position[maxLength];

    void reset();
    void grow();
    void move();
    void draw();

    void left() { velocityX = -1; velocityY = 0; };
    void right() { velocityX = 1; velocityY = 0; };
    void up() { velocityX = 0; velocityY = -1; };
    void down() { velocityX = 0; velocityY = 1; };

private:

};

class Food {
public:
    Food();
    ~Food();

    D2Point position;

    void place();
    void draw();
};

class Game {
    public:
        void draw();
        void draw(Snake &s, Food &f);
};

void Game::draw() {
    u8g2.firstPage();
    do {
        u8g2.setFont(u8g2_font_5x7_tf); // choose a suitable font
                if (!firstGame) {
            u8g2.drawStr(40, 14, "Game Over");
            u8g2.drawStr(40, 54, "Score:");
            u8g2.setCursor(75, 54);
            u8g2.print(score);
        }
        u8g2.drawStr(50, 24, "Snake");
        u8g2.drawStr(34, 34, "Press Button");
    } while (u8g2.nextPage());
}

void Game::draw(Snake &s, Food &f) {
    u8g2.firstPage();
    do {
        /* all graphics commands have to appear within the loop body. */
        u8g2.setFont(u8g2_font_5x7_tf); // choose a suitable font
        s.draw();
        f.draw();
    } while (u8g2.nextPage());
}

Snake::Snake() {
    velocityX =  0;
    velocityY = -1;

    length = 0;

    position[0].x = screenColumns / 2 * screenScale;
    position[0].y = screenRows / 2 * screenScale;
}

Snake::~Snake() {

}

void Snake::reset() {
    length = 0;
    position[0].x = screenColumns / 2 * screenScale;
    position[0].y = screenRows / 2 * screenScale;
    velocityX =  0;
    velocityY = -1;
}

void Snake::grow() {
    if ( length < (maxLength - 2 ) ) {
        length++;
    }
}

void Snake::move() {
    for (int i = length; i >= 0; i--) {
            position[i + 1].x = position[i].x;
            position[i + 1].y = position[i].y;
    }

    position[0].x = position[0].x + (velocityX * screenScale);
    position[0].y = position[0].y + (velocityY * screenScale);
}

void Snake::draw() {
    for (int i = length; i >= 0; i--) {
        u8g2.drawBox(position[i].x, position[i].y, screenScale, screenScale);
    }
}

Food::Food() {

}

Food::~Food() {

}

void Food::place() {
    position.x = random(screenColumns) * screenScale;
    position.y = random(screenRows)    * screenScale;
}

void Food::draw() {
    u8g2.drawBox(position.x, position.y, screenScale, screenScale);
}

Game game;
Snake snake;
Food food;

// The setup function runs once when you press reset or power the board
void setup() {
    u8g2.begin();

    pinMode(xAxisPin, INPUT);
    pinMode(yAxisPin, INPUT);
    pinMode(buttonPin, INPUT_PULLUP);
    pinMode(speakerPin, OUTPUT);

    randomSeed(analogRead(floatingPin));

    food.place();

    Serial.begin(115200);
}

// The loop function runs over and over again until power down or reset
void loop() {
    // gameOver separates the game into two states; running and attract
    if (!gameOver) {
        // Running state
        frameLimit--;
        if (frameLimit < 1) {
            frameLimit = frameSkip;

            joyX = analogRead(xAxisPin);
            joyY = analogRead(yAxisPin);
            joyB = digitalRead(buttonPin);

            // Test buttonState. If joyB is HIGH the button is not pressed
            if (joyB) {
                buttonState = false;
            }
            else {
                buttonState = true;
            }

            if ((joyX < 255) && (snake.velocityX == 0)) {
                snake.left();
            }
            else if ((joyX > 767) && (snake.velocityX == 0)) {
                snake.right();
            }
            else if ((joyY < 255) && (snake.velocityY == 0)) {
                snake.up();
            }
            else if ((joyY > 767) && (snake.velocityY == 0)) {
                snake.down();
            }

            if ( snake.position[0].x < 0 || snake.position[0].x > 127 || snake.position[0].y < 0 || snake.position[0].y > 63 ) {
                gameOver = true;
                beep(250);
            }

            for (int i = 1; i <= snake.length; i++) {
                if ((snake.position[0].x == snake.position[i].x) && (snake.position[0].y == snake.position[i].y)) {
                    gameOver = true;
                    beep(250);
                }
            }

            if ((snake.position[0].x == food.position.x) && (snake.position[0].y == food.position.y)) {
                snake.grow();
                food.place();
                score++;
                beep(50);
            }

            if (!gameOver) {
                snake.move();
            }

            // Print out joystick information to serial out
            print_status(joyX, joyY, joyB);

        }

        game.draw(snake, food);
    }
    else {
        // Attract state
        game.draw();

        joyB = digitalRead(buttonPin);

        // Test buttonState. If joyB is HIGH the button is not pressed
        if (joyB) {
            buttonState = false;
        }
        else {
            buttonState = true;
        }

        if (buttonState) {
            gameOver = false;
            firstGame = false;
            snake.reset();
            score = 0;
            beep(100);
        }
    }

    // Transfer internal memory to the display
    //u8g2.sendBuffer();

    // General Delay
    //delay(100);
}

void beep(int timeout) {
    digitalWrite(speakerPin, HIGH);
    delay(timeout);
    digitalWrite(speakerPin, LOW);
}

void print_status(int x, int y, int b) {
    //Serial.print("label");
    //Serial.print(variable);
    //Serial.print(", ");
    //Serial.print("label");
    //Serial.print(variable);
    //Serial.print(", ");
    Serial.print("X: ");
    Serial.print(x);
    Serial.print(", ");
    Serial.print("Y: ");
    Serial.print(y);
    Serial.print(", ");
    Serial.print("B: ");
    Serial.println(b);
}