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Small Game & Code Improvements #18

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184 changes: 99 additions & 85 deletions src/com/zetcode/Board.java
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Original file line number Diff line number Diff line change
@@ -1,12 +1,6 @@
package com.zetcode;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
Expand All @@ -17,68 +11,62 @@

public class Board extends JPanel implements ActionListener {

private final int B_WIDTH = 300;
private final int B_HEIGHT = 300;
private final int DOT_SIZE = 10;
private final int ALL_DOTS = 900;
private final int RAND_POS = 29;
private final int DELAY = 140;
private final int BOARD_WIDTH = 300;
private final int BOARD_HEIGHT = 300;
private final int DOT_SIZE = 10; //A 'dot' is a single segmentation of the snake's body.
private final int MAX_LENGTH = 900;
private final int RAND_POS = 29; //The value assigned here is the multiplier for the random value generated later.
private final int DELAY = 140; //The delay between 'ticks' of the game (refreshes of the game board)

private final int x[] = new int[ALL_DOTS];
private final int y[] = new int[ALL_DOTS];
private final int[] dotXPos = new int[MAX_LENGTH]; //Holds the x position of each dot on the snake.
private final int[] dotYPos = new int[MAX_LENGTH]; //Holds the y position of each dot on the snake.

private int dots;
private int apple_x;
private int apple_y;
//Property variables
private int currentSnakeLength;
private int appleXPos, appleYPos;

//Movement variables
private boolean leftDirection = false;
private boolean rightDirection = true;
private boolean upDirection = false;
private boolean downDirection = false;
private boolean inGame = true;

//Game-management variables
private boolean gameRunning = true;
private Timer timer;
private Image ball;
private Image apple;
private Image head;
private Image body, head, apple;

public Board() {

initBoard();
}

private void initBoard() {

addKeyListener(new TAdapter());
addKeyListener(new InputHandler());
setBackground(Color.black);
setFocusable(true);

setPreferredSize(new Dimension(B_WIDTH, B_HEIGHT));
setPreferredSize(new Dimension(BOARD_WIDTH, BOARD_HEIGHT));
loadImages();
initGame();
}

private void loadImages() {
body = new ImageIcon("src/resources/dot.png").getImage();

ImageIcon iid = new ImageIcon("src/resources/dot.png");
ball = iid.getImage();

ImageIcon iia = new ImageIcon("src/resources/apple.png");
apple = iia.getImage();
apple = new ImageIcon("src/resources/apple.png").getImage();

ImageIcon iih = new ImageIcon("src/resources/head.png");
head = iih.getImage();
head = new ImageIcon("src/resources/head.png").getImage();
}

private void initGame() {

dots = 3;
currentSnakeLength = 3;

for (int z = 0; z < dots; z++) {
x[z] = 50 - z * 10;
y[z] = 50;
for (int z = 0; z < currentSnakeLength; z++) {
dotXPos[z] = 50 - z * 10;
dotYPos[z] = 50;
}

locateApple();

timer = new Timer(DELAY, this);
Expand All @@ -91,18 +79,18 @@ public void paintComponent(Graphics g) {

doDrawing(g);
}

private void doDrawing(Graphics g) {

if (inGame) {

g.drawImage(apple, apple_x, apple_y, this);
if (gameRunning) {

for (int z = 0; z < dots; z++) {
g.drawImage(apple, appleXPos, appleYPos, this);

for (int z = 0; z < currentSnakeLength; z++) {
if (z == 0) {
g.drawImage(head, x[z], y[z], this);
g.drawImage(head, dotXPos[z], dotYPos[z], this);
} else {
g.drawImage(ball, x[z], y[z], this);
g.drawImage(body, dotXPos[z], dotYPos[z], this);
}
}

Expand All @@ -111,97 +99,115 @@ private void doDrawing(Graphics g) {
} else {

gameOver(g);
}
}
}

private void gameOver(Graphics g) {

String msg = "Game Over";
Font small = new Font("Helvetica", Font.BOLD, 14);
FontMetrics metr = getFontMetrics(small);

String gameOverMessage = "Game Over";
String restartMessage = "Press 'R' to Restart";

Font endGameFont = new Font("Helvetica", Font.BOLD, 28);

FontMetrics fontMetric = getFontMetrics(endGameFont);

int gameOverTextXPos = (BOARD_WIDTH - fontMetric.stringWidth(gameOverMessage)) / 2;
int gameOverTextYPos = (BOARD_HEIGHT / 2) - 30;

g.setColor(Color.white);
g.setFont(small);
g.drawString(msg, (B_WIDTH - metr.stringWidth(msg)) / 2, B_HEIGHT / 2);
g.setFont(endGameFont);
g.drawString(gameOverMessage, gameOverTextXPos, gameOverTextYPos);
g.drawString(restartMessage, gameOverTextXPos - 50, gameOverTextYPos + 60);
}

private void checkApple() {

if ((x[0] == apple_x) && (y[0] == apple_y)) {
//If the snake's head is at the same x and y pos of the apple, add to the length, and move the apple.
if ((dotXPos[0] == appleXPos) && (dotYPos[0] == appleYPos)) {

dots++;
currentSnakeLength++;
locateApple();
}
}

private void move() {

for (int z = dots; z > 0; z--) {
x[z] = x[(z - 1)];
y[z] = y[(z - 1)];
//Moves every piece of the snake's body to the x and y pos of the body-part in-front of it, creating the effect
//of the snake moving forward. This must be done *before* the snake's head is moved.
for (int z = currentSnakeLength; z > 0; z--) {
dotXPos[z] = dotXPos[(z - 1)];
dotYPos[z] = dotYPos[(z - 1)];
}

//Moves the head according to the enabled direction.
if (leftDirection) {
x[0] -= DOT_SIZE;
dotXPos[0] -= DOT_SIZE;
}

if (rightDirection) {
x[0] += DOT_SIZE;
dotXPos[0] += DOT_SIZE;
}

if (upDirection) {
y[0] -= DOT_SIZE;
dotYPos[0] -= DOT_SIZE;
}

if (downDirection) {
y[0] += DOT_SIZE;
dotYPos[0] += DOT_SIZE;
}
}

private void checkCollision() {

for (int z = dots; z > 0; z--) {

if ((z > 4) && (x[0] == x[z]) && (y[0] == y[z])) {
inGame = false;
/*
Loops through every part of the snake's body and for each piece checks to see if that piece is touching the
head. If it is, ends the game. Removed a check that was initially here which ignored collisions with early parts
of the body. With that check in place, it was super easy to pass straight through the body anytime you got trapped.
*/
for (int z = currentSnakeLength; z > 0; z--) {
if ((dotXPos[0] == dotXPos[z]) && (dotYPos[0] == dotYPos[z])) {
gameRunning = false;
}
}

if (y[0] >= B_HEIGHT) {
inGame = false;
//All of these checks are to ensure the snake is within the bounds of the game board.
if (dotYPos[0] >= BOARD_HEIGHT) {
gameRunning = false;
}

if (y[0] < 0) {
inGame = false;
if (dotYPos[0] < 0) {
gameRunning = false;
}

if (x[0] >= B_WIDTH) {
inGame = false;
if (dotXPos[0] >= BOARD_WIDTH) {
gameRunning = false;
}

if (x[0] < 0) {
inGame = false;
if (dotXPos[0] < 0) {
gameRunning = false;
}
if (!inGame) {

if (!gameRunning) {
timer.stop();
}
}

//Randomizes the x and y position of the apple.
private void locateApple() {

int r = (int) (Math.random() * RAND_POS);
apple_x = ((r * DOT_SIZE));
appleXPos = ((r * DOT_SIZE));

r = (int) (Math.random() * RAND_POS);
apple_y = ((r * DOT_SIZE));
appleYPos = ((r * DOT_SIZE));
}

//This is run every 'tick' of the game-loop. First everything is updated and refreshed, put in it's proper place,
//and then the screen is updated to reflect these changes.
@Override
public void actionPerformed(ActionEvent e) {

if (inGame) {

if (gameRunning) {
checkApple();
checkCollision();
move();
Expand All @@ -210,36 +216,44 @@ public void actionPerformed(ActionEvent e) {
repaint();
}

private class TAdapter extends KeyAdapter {
//Class responsible for the handling of user-input and movement of the snake
private class InputHandler extends KeyAdapter {

@Override
public void keyPressed(KeyEvent e) {

int key = e.getKeyCode();

if ((key == KeyEvent.VK_LEFT) && (!rightDirection)) {
//Added support for the 'w' 'a' 's' 'd' keys here
if ( ( (key == KeyEvent.VK_LEFT) || (key == KeyEvent.VK_A) ) && (!rightDirection)) {
leftDirection = true;
upDirection = false;
downDirection = false;
}

if ((key == KeyEvent.VK_RIGHT) && (!leftDirection)) {
if ( ( (key == KeyEvent.VK_RIGHT) || (key == KeyEvent.VK_D) ) && (!leftDirection)) {
rightDirection = true;
upDirection = false;
downDirection = false;
}

if ((key == KeyEvent.VK_UP) && (!downDirection)) {
if ( ( (key == KeyEvent.VK_UP) || (key == KeyEvent.VK_W) ) && (!downDirection)) {
upDirection = true;
rightDirection = false;
leftDirection = false;
}

if ((key == KeyEvent.VK_DOWN) && (!upDirection)) {
if ( ( (key == KeyEvent.VK_DOWN) || (key == KeyEvent.VK_S) ) && (!upDirection)) {
downDirection = true;
rightDirection = false;
leftDirection = false;
}

if(key == KeyEvent.VK_R && !gameRunning){
Snake.restartGame();
}

}

}
}
32 changes: 22 additions & 10 deletions src/com/zetcode/Snake.java
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Original file line number Diff line number Diff line change
@@ -1,33 +1,45 @@
package com.zetcode;

import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.*;

public class Snake extends JFrame {

private static JFrame frame;

public Snake() {

initUI();
}

private void initUI() {

add(new Board());

setResizable(false);
pack();

setTitle("Snake");
setIconImage(new ImageIcon("src/resources/icon.png").getImage());
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}


//Basic method for restarting the game via disposing the current frame and initializing a new one.
public static void restartGame(){
frame.dispose();

startGame();
}

public static void main(String[] args) {

startGame();
}

private static void startGame(){
EventQueue.invokeLater(() -> {
JFrame ex = new Snake();
ex.setVisible(true);
frame = new Snake();
frame.setVisible(true);
});
}

}
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