//SimplePong is a java applet written by Daniel Moscufo //of scufo http://www.esearch.com.au/scufo. It can be //considered freeware. import java.applet.Applet; import java.awt.*; import java.awt.event.*; import java.lang.Math; import java.net.*; import java.awt.image.*; public class SimplePong extends Applet { public void init() { //Set default colour=black, width=300, height=80 //Difficulty =5, image = backing.gif int bcRed = 0; int bcBlue = 0; int bcGreen = 0; int Width = 300; int Height = 80; int Difficulty = 5; String backimage = "backing.gif"; //Check for user parameters if(getParameter("Red")!=null) bcRed = new Integer(getParameter("Red").trim()).intValue(); if(getParameter("Blue")!=null) bcBlue = new Integer(getParameter("Blue").trim()).intValue(); if(getParameter("Green")!=null) bcGreen = new Integer(getParameter("Green").trim()).intValue(); if(getParameter("Width")!=null) Width = new Integer(getParameter("Width").trim()).intValue() -20; if(getParameter("Height")!=null) Height = new Integer(getParameter("Height").trim()).intValue()-20; if(getParameter("Difficulty")!=null) Difficulty = new Integer(getParameter("Difficulty").trim()).intValue(); if(getParameter("BackImage")!=null) backimage= getParameter("BackImage"); //Set these above values setBackground(new Color(bcRed,bcGreen,bcBlue)); Image ball = getImage(getCodeBase(), "ball.gif"); Image paddle1 = getImage(getCodeBase(),"panel1.gif"); Image paddle2 = getImage(getCodeBase(),"panel2.gif"); Image back = getImage(getCodeBase(),backimage); Image toplay = getImage(getCodeBase(),"Toplay.gif"); //Create new Pongtable with correct values PongTable pongtable = new PongTable(Width,Height,ball,paddle1,paddle2,back,toplay, Difficulty); //this below code is just to add a centered pong game setLayout(new BorderLayout()); Panel centredpanel = new Panel(); centredpanel.add(pongtable); add(centredpanel, "Center"); } } class PongTable extends Canvas implements Runnable, MouseMotionListener, MouseListener { int Xsize, Ysize, Xball, Yball, Xbat, Ybat, XbatC, YbatC, difficulty; double direction[] = new double[2]; Thread thisthread; int Xbatdir[] = new int[2]; int Ybatdir[] = new int[2]; boolean Centred = true; Image ball, paddle1, paddle2, back, toplay; //AudioClip pong; PongTable(int xsize, int ysize, Image Ball, Image Paddle1, Image Paddle2, Image Back, Image Toplay, int Difficulty) { //This method just setups all the variables Toolkit toolkit = Toolkit.getDefaultToolkit(); addMouseMotionListener(this); addMouseListener(this); setSize(xsize,ysize); Xsize = xsize; Ysize = ysize; startpositions(); Xball = (int)Xsize/2; Yball = (int)Ysize/2; direction[0] = 0; direction[1] = 0; ball = Ball; paddle1 = Paddle1; paddle2 = Paddle2; back = Back; toplay = Toplay; difficulty = Difficulty; //Start the thread. thisthread = new Thread(this); thisthread.start(); } void startpositions() { //Specify the start positions Xball = 20; Yball = 20; Xbat = 20; Ybat = 40; XbatC = Xsize -20; YbatC = 40; direction[0] = 4.0; //X velocity vector direction[1] = 4.0; //Y velocity vector } public void update(Graphics g) { //This is just your standard double buffering update method Graphics offgraph; Image offscreen = null; Dimension d = getSize(); offscreen = createImage(d.width, d.height); offgraph = offscreen.getGraphics(); offgraph.setColor(getBackground()); offgraph.fillRect(0, 0, d.width, d.height); offgraph.setColor(getForeground()); paint(offgraph); g.drawImage(offscreen, 0, 0, this); offscreen.flush(); } public void paint(Graphics g) { //Draw Background Image g.drawImage(back,5,5,Xsize-10,Ysize-10,this); //Draw users bat g.drawImage(paddle1,XbatC-2,YbatC-10,this); //Draw computer bat g.drawImage(paddle2,Xbat-2,Ybat-10,this); //draw ball g.drawImage(ball,Xball-5, Yball-5,this); //check if no one is playing and display "click to play" if(Centred) g.drawImage(toplay,10, 10,this); } public void run() { double Xballdb, Yballdb; Xballdb = Xball; Yballdb = Yball; int n; while(true) { //We check for ball hitting surface 4 times for every repaint() for(n=0;n<4;n++) { //increase X & Y by velocity/4 Xballdb = Xballdb + direction[0]/4; Yballdb = Yballdb + direction[1]/4; //check if ball hit either "goal" //centred tells that game is over if(Xballdb<10 || Xballdb>Xsize-10) { Xballdb = Xsize/2; Yballdb = Ysize/2; direction[0] = 0; direction[1] = 0; Centred = true; } //Check if ball hits either top or bottom wall // if so change y to = -y if(Yballdb<10 || Yballdb>Ysize-10) { direction[1]=-1*direction[1]; } //Now we see if bat hits players bat if(Xballdb>18 && Xballdb<27)//X thickness of bat //check if ball is within 10 pixels Y dirn //of bat if(Math.abs(Yballdb-Ybat)<=10) { //if so x = -x + x bat movement dirn, //y = -y + y bat movement dirn direction[0] = -1*direction[0]+(int)((Xbatdir[0]-Xbatdir[1])/8); direction[1] = direction[1]+(int)((Ybatdir[0]-Ybatdir[1])/8); //place ball at front of bat Xballdb=28; } //Now we do the same for computer bat if(Xballdb<(Xsize-15) && Xballdb>(Xsize-22)) if(Math.abs(Yballdb-YbatC)<=10) { //x = -x - random no. direction[0] = -1*direction[0] + -1*Math.random(); //y = -y + random no proportional to x speed //This helps in stopping the ball going //back and further on same y value direction[1] = direction[1] + (direction[0]/4)*Math.sin(Math.random()*2*Math.PI); //place ball on front of bat Xballdb=Xsize-23; } } //send paint correct coords Xball = (int)Xballdb; Yball = (int)Yballdb; //ok now do Computer AI //check ball in our half if(Xball>Xsize/2) { //ok this algorithym is simple but effective //firstly check the bat and ball aren't the same height //then find if bat is above or below the bat //then move bat up/down by difficulty pixels if((Yball-YbatC)!=0) YbatC = (Yball-YbatC)/(Math.abs(Yball-YbatC))*difficulty + YbatC; } //recall the paint method repaint(); //Ok sleep the thread fo 50 ms try { thisthread.sleep(50); } catch(Exception e) { System.out.println("Error on sleep"); } } } public void mouseMoved(MouseEvent e) { int x = e.getX(); int y = e.getY(); //Ok here we move the bat by setting it equal to mouse height if(y>15 && y