GamePanel.java

package com.maverickar;

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.util.Random;

import javax.swing.JPanel;

public class GamePanel extends JPanel implements Runnable {
	
	static final int GAME_WIDTH = 1000;
	static final int GAME_HEIGHT = (int) (GAME_WIDTH * (0.5555));
	static final Dimension SCREEN_SIZE = new Dimension (GAME_WIDTH, GAME_HEIGHT);
	static final int BALL_DIAMETER = 20;
	static final int PADDLE_WIDTH = 25;
	static final int PADDLE_HEIGHT = 100;
	
	Thread gameThread;
	Image image;
	Graphics graphics;
	Random random;
	Paddle paddle1;
	Paddle paddle2;
	Ball ball;
	Score score;
	
	GamePanel(){
		newPaddles();
		newBall();
		score = new Score(GAME_WIDTH, GAME_HEIGHT);
		this.setFocusable(true); 
		this.addKeyListener(new AL());
		this.setPreferredSize(SCREEN_SIZE);
		
		gameThread = new Thread(this);
		gameThread.start();
	}
	
	public void newBall() {
		
		ball = new Ball((GAME_WIDTH/2)-(BALL_DIAMETER/2),(GAME_HEIGHT/2)-(BALL_DIAMETER/2),BALL_DIAMETER,BALL_DIAMETER);
	}
	
	public void newPaddles() {
		paddle1 = new Paddle(0, (GAME_HEIGHT/2)-(PADDLE_HEIGHT/2), PADDLE_WIDTH, PADDLE_HEIGHT, 1); 
		paddle2 = new Paddle(GAME_WIDTH-PADDLE_WIDTH, (GAME_HEIGHT/2)-(PADDLE_HEIGHT/2), PADDLE_WIDTH, PADDLE_HEIGHT, 2);
	}
	
	public void paintComponent(Graphics g) {
		image = createImage(getWidth(),getHeight());
		graphics = image.getGraphics();
		draw(graphics);
		g.drawImage(image,0,0,this);
		paddle1.draw(g);
		paddle2.draw(g);
		ball.draw(g);
		score.draw(g);
	}
	
	public void move() {
		paddle1.move();
		paddle2.move();
		ball.move();
	}
	
	public void checkCollision() {
		// bounces the ball off paddles
		if(ball.intersects(paddle1)) {
			ball.xVelocity = ball.xVelocity * -1;
		}
		if(ball.intersects(paddle2)) {
			ball.xVelocity = ball.xVelocity * -1;
		}
		// bounce the ball off the top and bottom window edges
		if(ball.y <= 0) {
			ball.setYDirection(-ball.yVelocity);
		}
		if(ball.y >= GAME_HEIGHT-BALL_DIAMETER) {
			ball.setYDirection(-ball.yVelocity);
		}
		
		// stops paddles at window edges
		if(paddle1.y <= 0) {
			paddle1.y = 0;
		}
		if(paddle1.y >= (GAME_HEIGHT)-(PADDLE_HEIGHT)) {
			paddle1.y = GAME_HEIGHT-PADDLE_HEIGHT;
		}
		if(paddle2.y <= 0) {
			paddle2.y = 0;
		}
		if(paddle2.y >= (GAME_HEIGHT)-(PADDLE_HEIGHT)) {
			paddle2.y = GAME_HEIGHT-PADDLE_HEIGHT;
		}
		
		// give a player 1 point and creates new Paddles and Ball
		if(ball.x <=0) {
			score.player2++;
			newPaddles();
			newBall();
			
		} 
		if(ball.x >= GAME_WIDTH-BALL_DIAMETER) {
			score.player1++;
			newPaddles();
			newBall();
			
		} 
	}
	
	// game loop, wtaf
	public void run() {
		long lastTime = System.nanoTime();
		double amountOfTicks = 60.0;
		double ns = 1000000000 / amountOfTicks;
		double delta = 0;
		while(true) {
			long now = System.nanoTime();
			delta += (now-lastTime)/ns;
			lastTime = now;
			if(delta >=1) {
				move();
				checkCollision();
				repaint();
				delta--;
			}
		}
	}
	
	public class AL extends KeyAdapter {
		public void keyPressed(KeyEvent e) {
			paddle1.keyPressed(e);
			paddle2.keyPressed(e);
		}
		
		public void keyReleased(KeyEvent e) {
			paddle1.keyReleased(e);
			paddle2.keyReleased(e);
		}
	}
}