Problem with writing code.

[Martin vanPutten]

I can't think of what to do. What I want is the ball to bounce off the paddle if it hits the paddle. The paddle is defined to 80. And then if it doesn't then it keeps going until it hits the edge where I set it so the timer stops. I can't think right as to what to do... its like a brain freeze! How can I set it so that it if it hits the paddles range and bouces off?

  import java.applet.Applet; 
import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*;   
 
/*//////////////////// 
Pong////////////////// 
Martin vanPutten////// 
Woodstock High School/ 
*/////////////////////  
 
public class Pong extends Applet   
 
{ // Pong Applet.   
 
int x = 1; // Controller Pad Width.
int y = 215; // Controller Pad Length.
int xx = 789; //Computer Pad Width.
int yy = 210; // Computer Pad Length.
int X = 10; // Ball Width.
int Y = 235; // Ball Length.
int t = 0; // Top Border.
int b = 420; // Bottom Border. 
int yIncrement; // Balls Y-Axis Incrementing. 
int xIncrement; // Balls X-Axis Incrementing.  
 
Timer timerUp; // Timer Up Pad. 
Timer timerDown; // Timer Down Pad. 
Timer timerBall; // Timer Ball. 
Timer timerAI; // Timer AI.

Tester Test1 = new Tester(); // Performs Test Class. 

public void init ()  
 
{ // Initialize.  
 
setBackground (Color.black); // Background Color.  

timerUp = new Timer (-200, new TimeListenerUp ()); // Pulls TimeListenerUp Class. 
timerDown = new Timer (-200, new TimeListenerDown ()); // Pulls TimeListenerDown Class. 
timerBall = new Timer (-200, new TimeListenerBall ()); // Pulls TimeListenerBall Class. 
timerAI = new Timer (-200, new TimeListenerAI ()); // Pulls TimeListenerAI Class.  

Test1.trial (1, 0); // Test.

addKeyListener (new KeyAdapter () // Key Listener.  
 
{ // Keys.              
 
public void keyPressed (KeyEvent keP)              
 
{ // Keys Pressed.                  
 
if (keP.getKeyCode () == KeyEvent.VK_ENTER) // Starts Pong.  
 
{ // Starts Components.  
 
timerBall.start (); // Start Ball Component. 
timerAI.start (); // Start AI Component. 

Test1.trial (0, 1); // Test.
    repaint ();
       
} //End Starts Components.  
 
if (keP.getKeyCode () == KeyEvent.VK_UP) // Start Up.         
timerUp.start ();          
 
if (keP.getKeyCode () == KeyEvent.VK_DOWN) // Start Down.         
timerDown.start ();        

if (y <= t)  
 
{ // Up Restriction.  
 
timerUp.stop (); 
y = 0;  
 
} // End Up Restriction. 
 
if (y >= b)  

{ // Down Restriction.  

timerDown.stop (); 
y = 420;  

} // End Down Restriction. 

} // End Keys Pressed.  

public void keyReleased (KeyEvent keR)  

{ // Keys Released.  

if (keR.getKeyCode () == KeyEvent.VK_UP) // Stop Up.         
timerUp.stop ();          

if (keR.getKeyCode () == KeyEvent.VK_DOWN) // Stop Down.         
timerDown.stop ();     

} // Keys Released.          

} // End Keys.                  

); // End Key Listener.    

} // End Initialize.   

public void paint (Graphics g)  

{ // Graphics.  

g.setColor (Color.yellow); // Controller Pad.
g.fillRect (x, y, 10, 80);

g.fillRect (xx, yy, 10, 80); // Computer Pad.

g.setColor (Color.blue); // Border.
g.drawRect (0, 0, 799, 499);

g.setColor (Color.blue); // Center Line.
g.drawRect (400, 0, 1, 500);

if (Test1.Test == 1)

{ // Show Title.

g.setColor (Color.white); // Information.
g.drawString ("Pong!!", 100, 75);
g.drawString ("By: Martin vanPutten.", 100, 90);
g.drawString ("Click ENTER to start game.", 100, 105);  

} // End Show Title.

if (Test1.Test == 2)

{ // Don't Show Title.

g.setColor (Color.black);
g.drawString ("Pong!!", 100, 75);
g.drawString ("By: Martin vanPutten.", 100, 90);
g.drawString ("Click ENTER to start game.", 100, 105);

} // End Don't Show Title.

g.setColor (Color.white); // Ball.
g.fillOval (X, Y, 30, 30);

} // End Graphics.  

public class TimeListenerUp implements ActionListener  

{ // TimeListenerUp Class.  

public void actionPerformed(ActionEvent event)  

{ // Repaints Up Movements.  

y--; 
repaint ();  

} // End Repaints Up Movements.  

} // End TimeListenerUp Class.  

public class TimeListenerDown implements ActionListener  

{ // TimeListenerDown Class.  

public void actionPerformed(ActionEvent event)  

{ // Repaints Down Movements.  

y++; 
repaint ();  

} // End Repaints Down Movements.  

} // End TimeListenerDown Class.  

public class TimeListenerBall implements ActionListener  

{ // TimeListenerBall Class.  

public void actionPerformed(ActionEvent event)  

{ // Repaints Ball Movements.  

Y++; 
X++;  

Y += yIncrement; 
X += xIncrement;    

if (Y == 474) // Bounce Ball Up.      
yIncrement += -1;      

if (Y == 0)  // Bounce Ball Down.     
yIncrement += 1;    

if (X == 759) // Bounce Ball Left. 
xIncrement += -1; 

if (X == 10) // Bounce Ball Right.
xIncrement += 1; 

if (X == 0) // Stops Player Game.
timerBall.stop ();

if (X == 770) // Stops Computer Game.
timerBall.stop (); 

repaint ();  

} // End Repaints Ball Movements.  

} // End TimeListenerBall Class.  

public class TimeListenerAI implements ActionListener  

{ // TimeListenerAI Class.  

public void actionPerformed(ActionEvent event)  

{ // Repaints AI Movements.  

yy = Y - 25;

if (Y >= 445) // Stops Down Movement.
yy = 420;
else 
yy--;

if (Y <= 25) // Stops Up Movement.
yy = 0;
else
yy++;

repaint (); 

} // End Repaints AI Movements.  

} // End TimeListenerAI Class.  

} // End Pong Applet.  

class Tester
       
    { // Tester Class.
    
    int Test; // Test.

public void trial (int Yes, int No) 
       
    { // Create Test.
    
    if (Yes == 1 && No == 0)
    Test = 1;
    else if (Yes == 0 && No == 1)
Test = 2; 
    
    } // End Create Test.
       
} // End Tester Class.  

 <HTML>
<HEAD>
</HEAD>
<BODY BGCOLOR="000000">
<CENTER>
<APPLET
code= "Pong.class"
width= "800"
height= "500"
>
</APPLET>
</CENTER>
</BODY>
</HTML>
   

[Justin Fox]

set a certain point on the line of the padel to a constant, and:

if (ballX == Paddle2X)//assuming paddle 2 is on the right.
ballX --;
else
ballX ++;

and you can have a Paddle1 constant also, so you can do the same for it.

if(ballX == Paddle1X)//assuming paddle 1 is on the left.
ballX ++;
else
ballX --;

and have this in a timer listener "BallListener" or something like that.

-Justin-

[ May 08, 2006: Message edited by: Justin Fox ]
[ May 08, 2006: Message edited by: Justin Fox ]

[Martin vanPutten]

Thanks again Justin for your advice. I'm almost done the game!! Now I want to turn the entire screen black when somebody loses. So if X = 0 then fill area black. But I still get flashing form the other objects. I think its because of the timer. How can I fix this with what I have now?

  import java.applet.Applet; 
import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*;   
 
/*//////////////////// 
Pong////////////////// 
Martin vanPutten////// 
Woodstock High School/ 
*/////////////////////  
 
public class Pong extends Applet   
 
{ // Pong Applet.   
 
int x = 1; // Controller Pad Width.
int y = 215; // Controller Pad Length.
int xx = 789; //Computer Pad Width.
int yy = 210; // Computer Pad Length.
int X = 10; // Ball Width.
int Y = 235; // Ball Length.
int pTop; // Center Point Of Ball Hitting Top Of Paddle.
int pBottom; // Center Point Of Ball Hitting Bottom Of Paddle.
int t = 0; // Top Border.
int b = 420; // Bottom Border. 
int yIncrement; // Balls Y-Axis Incrementing. 
int xIncrement; // Balls X-Axis Incrementing. 

Timer timerUp; // Timer Up Pad. 
Timer timerDown; // Timer Down Pad. 
Timer timerBall; // Timer Ball. 
Timer timerAI; // Timer AI.

Tester Test1 = new Tester(); // Performs Test Class. 

public void init ()  
 
{ // Initialize.  
 
setBackground (Color.black); // Background Color.  

timerUp = new Timer (-200, new TimeListenerUp ()); // Pulls TimeListenerUp Class. 
timerDown = new Timer (-200, new TimeListenerDown ()); // Pulls TimeListenerDown Class. 
timerBall = new Timer (-200, new TimeListenerBall ()); // Pulls TimeListenerBall Class. 
timerAI = new Timer (-200, new TimeListenerAI ()); // Pulls TimeListenerAI Class.  

Test1.trial (1, 0); // Test.

addKeyListener (new KeyAdapter () // Key Listener.  
 
{ // Keys.              
 
public void keyPressed (KeyEvent keP)              
 
{ // Keys Pressed.                  
 
if (keP.getKeyCode () == KeyEvent.VK_ENTER) // Starts Pong.  
 
{ // Starts Components.  
 
timerBall.start (); // Start Ball Component. 
timerAI.start (); // Start AI Component. 

Test1.trial (0, 1); // Test.
    repaint ();
       
} //End Starts Components.  
 
if (keP.getKeyCode () == KeyEvent.VK_UP) // Start Up.         
timerUp.start ();          
 
if (keP.getKeyCode () == KeyEvent.VK_DOWN) // Start Down.         
timerDown.start ();        

if (y <= t)  
 
{ // Up Restriction.  
 
timerUp.stop (); 
y = 0;  
 
} // End Up Restriction. 
 
if (y >= b)  

{ // Down Restriction.  

timerDown.stop (); 
y = 420;  

} // End Down Restriction. 

} // End Keys Pressed.  

public void keyReleased (KeyEvent keR)  

{ // Keys Released.  

if (keR.getKeyCode () == KeyEvent.VK_UP) // Stop Up.         
timerUp.stop ();          

if (keR.getKeyCode () == KeyEvent.VK_DOWN) // Stop Down.         
timerDown.stop ();     

} // Keys Released.          

} // End Keys.                  

); // End Key Listener.    

} // End Initialize.   

public void paint (Graphics g)  

{ // Graphics.  

g.setColor (Color.yellow); // Controller Pad.
g.fillRect (x, y, 10, 80);

g.fillRect (xx, yy, 10, 80); // Computer Pad.

g.setColor (Color.blue); // Border.
g.drawRect (0, 0, 799, 499);

g.setColor (Color.blue); // Center Line.
g.drawRect (400, 0, 1, 500);

if (Test1.Test == 1)

{ // Show Title.

g.setColor (Color.white); // Information.
g.drawString ("Pong!!", 100, 75);
g.drawString ("By: Martin vanPutten.", 100, 90);
g.drawString ("Click ENTER to start game.", 100, 105);  

} // End Show Title.

if (Test1.Test == 2)

{ // Don't Show Title.

g.setColor (Color.black);
g.drawString ("Pong!!", 100, 75);
g.drawString ("By: Martin vanPutten.", 100, 90);
g.drawString ("Click ENTER to start game.", 100, 105);

} // End Don't Show Title.

g.setColor (Color.white); // Ball.
g.fillOval (X, Y, 30, 30);

if (X == 0 || X == 770)

{ // Ends Game.

g.setColor (Color.black);
g.fillRect (0, 0, 800, 500);

} // End Ends Game.

} // End Graphics.  

public class TimeListenerUp implements ActionListener  

{ // TimeListenerUp Class.  

public void actionPerformed(ActionEvent event)  

{ // Repaints Up Movements.  

y--; 
repaint ();  

} // End Repaints Up Movements.  

} // End TimeListenerUp Class.  

public class TimeListenerDown implements ActionListener  

{ // TimeListenerDown Class.  

public void actionPerformed(ActionEvent event)  

{ // Repaints Down Movements.  

y++; 
repaint ();  

} // End Repaints Down Movements.  

} // End TimeListenerDown Class.  

public class TimeListenerBall implements ActionListener  

{ // TimeListenerBall Class.  

public void actionPerformed(ActionEvent event)  

{ // Repaints Ball Movements.  

pTop = Y + 15;
pBottom = Y - 15;

Y++; 
X++;  

Y += yIncrement; 
X += xIncrement;    

if (Y == 474) // Bounce Ball Up.      
yIncrement += -1;      

if (Y == 0)  // Bounce Ball Down.     
yIncrement += 1;    

if (X == 759) // Bounce Ball Left. 
xIncrement += -1; 

if (X == 10 && pTop >= y && pBottom <= (y + 80)) // Bounce Ball Right.
xIncrement += 1; 

if (X == 0) // Computer Wins.

{ // Stops Controls.

timerBall.stop ();
timerUp.stop ();
timerDown.stop ();

} // End Stops Controls.

if (X == 770) // Player Wins.

{ // Stops Controls.

timerBall.stop ();
timerUp.stop ();
timerDown.stop ();

} // End Stops Controls.

repaint ();  

} // End Repaints Ball Movements.  

} // End TimeListenerBall Class.  

public class TimeListenerAI implements ActionListener  

{ // TimeListenerAI Class.  

public void actionPerformed(ActionEvent event)  

{ // Repaints AI Movements.  

yy = Y - 25;

if (Y >= 445) // Stops Down Movement.
yy = 420;
else 
yy--;

if (Y <= 25) // Stops Up Movement.
yy = 0;
else
yy++;

repaint (); 

} // End Repaints AI Movements.  

} // End TimeListenerAI Class.  

} // End Pong Applet.  

class Tester
       
    { // Tester Class.
    
    int Test; // Test.

public void trial (int Yes, int No) 
       
    { // Create Test.
    
    if (Yes == 1 && No == 0)
    Test = 1;
    else if (Yes == 0 && No == 1)
Test = 2; 
    
    } // End Create Test.
       
} // End Tester Class.    

[Martin vanPutten]

K... fixed that part. Now I have a general question. I want to get rid of the flashing between all of my objects and I have a feeling its because I'm using Timers. My friend said that I may be able to fix it using something buffer? I can't remember what exactly it was but is there some type of buffer that will get rid of the flashing?

[Keith Lynn]

I think your friend means double buffering. The basic process is that you create an image offscreen and do all your drawing on it. Then when it is complete you copy the image in memory into the visible area.