Programming Forums > Application Development > Java

Alittlelost · Feb 20th, 2008, 6:02 PM

Hey everyone,

I tried looking around pretty much everywhere i could think of but i havnt been able to come up with a solution to my problem, which ill explain in a minute.

This is my first time making any sort of videogame so im a complete beginner to some of the methods involved. I am attempting to make a 2d pong java applet. So far I have the background colored. The paddle and ball on the screen. User input works to move the paddle up and down. The ball moves randomly and resets to its original position after reaching a certain x-coordinate (best way i could think of). The ball also bounces off the right,top and bottom 'walls'.

This idea of the game is basically a single player game of squash, so that for now, i can avoid AI.

Sorry for going on so much, but my problem is that I cannot find a way to create collsion detection between the paddle (a rectangle made with g.fillRect) and the ball (made with g.fillOval). I have tried using the Rectangle class and creating an intersects boolean but with no success, my code compiled but it seemed to have no effect.

Here is my code, thanks a lot for any help and thanks for reading this.

(Toggle Plain Text)

import java.applet.*;
import java.awt.*;
import java.util.*;
import java.math.*;

public class Ball extends Applet implements Runnable
{
	
	int x_pos = 590, y_pos = 100, radius = 20, appletsize_x = 800, appletsize_y = 600, x_speed=0, y_speed=0;
	
	int x_pos1 = 100, y_pos1 = 100, x_speed1, y_speed1;
	
	int limit = 100;
	
	Random rnd = new Random();
		
	private Image dbImage;
	private Graphics dbg;

	public void init()
	{
		setBackground (Color.blue);
	}

	public void start ()
	{
		
		Thread th = new Thread (this);
		
		th.start ();
	}

	public void stop()
	{

	}

	public void destroy()
	{

	}

	public void run ()
	{
		
			Thread.currentThread().setPriority(Thread.MIN_PRIORITY);

		
		while (true)
		{
			if (x_pos > appletsize_x - radius)
			{
				x_speed = -10; 
			}
	
			else if (x_pos < radius)
			{
				x_speed = +10; 
			}
			
			else if (y_pos > appletsize_y - radius)
			{
				y_speed = -10;  
			}
			
			else if (y_pos < radius)
			{
				y_speed = +10;
			}
			
			else if (x_pos < x_pos1-50)///////////////////////////
			{
				x_pos = 590;
				y_pos = rnd.nextInt(600);
			}
			
			x_pos += x_speed;
			y_pos += y_speed;
			
			
			
			
			
			
			if (x_pos1 > appletsize_x - radius)
			{
				x_speed1 = -10;
			
			}
	
			else if (x_pos1 < radius)
			{
				x_speed1 = +10; 
			}
			
			else if (y_pos1 > appletsize_y - radius*4)
			{
				y_speed1 = -10;  
			}
			
			else if (y_pos1 < radius)
			{
				y_speed1 = +10;
			}
			
			
			x_pos1 += x_speed1;
			y_pos1 += y_speed1;

			
			repaint();

			try
			{
				Thread.sleep (20);
			}
			
			catch (InterruptedException ex)
			{
				
			}

			Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
		}
	}

	
	public void update (Graphics g)
	{
		
		if (dbImage == null)
		{
			dbImage = createImage (this.getSize().width, this.getSize().height);
			dbg = dbImage.getGraphics ();
		}

		
		dbg.setColor (getBackground ());
		dbg.fillRect (0, 0, this.getSize().width, this.getSize().height);

		
		dbg.setColor (getForeground());
		paint (dbg);

		
		g.drawImage (dbImage, 0, 0, this);
	}

	public void paint (Graphics g)
	{
		g.setColor  (Color.red);

		g.fillOval  (x_pos - radius, y_pos - radius, 2 * radius, 2 * radius);
		
		g.setColor  (Color.green);

		g.fillRect  (x_pos1 - radius, y_pos1 - radius, 2 * radius, 2 * radius+50);
	}
	
	public boolean keyDown (Event e, int key)
{

      if (key == Event.LEFT)
      {
            x_speed = -10;
            y_speed = 0;
      }
      
      else if (key == Event.RIGHT)
      {
            x_speed = 10;
            y_speed = 0;
      }
      
      else if (key == Event.DOWN)
      {
      		y_speed = 10;
      		x_speed = 0;
      }
      
      else if (key == Event.UP)
      {
      		y_speed = -10;
      		x_speed = 0;
      }
      
      else if (key == 32)
      {
            x_speed = -10;
            y_speed = +10;
      }
      else
      {
            System.out.println ("Character: " + (char)key + " Integer Value: " + key);
      }
      
      if (key == 113)
      {
            x_speed1 = 0;
            y_speed1 = -10;
      }
      
      else if (key == 97)
      {
            x_speed1 = 0;
            y_speed1 = +10;
      }
      
      //else if (key == 32)
      //{
      //      x_speed1 = 0;
      //      y_speed1 = 0;
      //}
      else
      {
            System.out.println ("Character: " + (char)key + " Integer Value: " + key);
      }

      return true;

}
}

import java.applet.*;
import java.awt.*;
import java.util.*;
import java.math.*;

public class Ball extends Applet implements Runnable
{
	
	int x_pos = 590, y_pos = 100, radius = 20, appletsize_x = 800, appletsize_y = 600, x_speed=0, y_speed=0;
	
	int x_pos1 = 100, y_pos1 = 100, x_speed1, y_speed1;
	
	int limit = 100;
	
	Random rnd = new Random();
		
	private Image dbImage;
	private Graphics dbg;

	public void init()
	{
		setBackground (Color.blue);
	}

	public void start ()
	{
		
		Thread th = new Thread (this);
		
		th.start ();
	}

	public void stop()
	{

	}

	public void destroy()
	{

	}

	public void run ()
	{
		
			Thread.currentThread().setPriority(Thread.MIN_PRIORITY);

		
		while (true)
		{
			if (x_pos > appletsize_x - radius)
			{
				x_speed = -10; 
			}
	
			else if (x_pos < radius)
			{
				x_speed = +10; 
			}
			
			else if (y_pos > appletsize_y - radius)
			{
				y_speed = -10;  
			}
			
			else if (y_pos < radius)
			{
				y_speed = +10;
			}
			
			else if (x_pos < x_pos1-50)///////////////////////////
			{
				x_pos = 590;
				y_pos = rnd.nextInt(600);
			}
			
			x_pos += x_speed;
			y_pos += y_speed;
			
			
			
			
			
			
			if (x_pos1 > appletsize_x - radius)
			{
				x_speed1 = -10;
			
			}
	
			else if (x_pos1 < radius)
			{
				x_speed1 = +10; 
			}
			
			else if (y_pos1 > appletsize_y - radius*4)
			{
				y_speed1 = -10;  
			}
			
			else if (y_pos1 < radius)
			{
				y_speed1 = +10;
			}
			
			
			x_pos1 += x_speed1;
			y_pos1 += y_speed1;

			
			repaint();

			try
			{
				Thread.sleep (20);
			}
			
			catch (InterruptedException ex)
			{
				
			}

			Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
		}
	}

	
	public void update (Graphics g)
	{
		
		if (dbImage == null)
		{
			dbImage = createImage (this.getSize().width, this.getSize().height);
			dbg = dbImage.getGraphics ();
		}

		
		dbg.setColor (getBackground ());
		dbg.fillRect (0, 0, this.getSize().width, this.getSize().height);

		
		dbg.setColor (getForeground());
		paint (dbg);

		
		g.drawImage (dbImage, 0, 0, this);
	}

	public void paint (Graphics g)
	{
		g.setColor  (Color.red);

		g.fillOval  (x_pos - radius, y_pos - radius, 2 * radius, 2 * radius);
		
		g.setColor  (Color.green);

		g.fillRect  (x_pos1 - radius, y_pos1 - radius, 2 * radius, 2 * radius+50);
	}
	
	public boolean keyDown (Event e, int key)
{

      if (key == Event.LEFT)
      {
            x_speed = -10;
            y_speed = 0;
      }
      
      else if (key == Event.RIGHT)
      {
            x_speed = 10;
            y_speed = 0;
      }
      
      else if (key == Event.DOWN)
      {
      		y_speed = 10;
      		x_speed = 0;
      }
      
      else if (key == Event.UP)
      {
      		y_speed = -10;
      		x_speed = 0;
      }
      
      else if (key == 32)
      {
            x_speed = -10;
            y_speed = +10;
      }
      else
      {
            System.out.println ("Character: " + (char)key + " Integer Value: " + key);
      }
      
      if (key == 113)
      {
            x_speed1 = 0;
            y_speed1 = -10;
      }
      
      else if (key == 97)
      {
            x_speed1 = 0;
            y_speed1 = +10;
      }
      
      //else if (key == 32)
      //{
      //      x_speed1 = 0;
      //      y_speed1 = 0;
      //}
      else
      {
            System.out.println ("Character: " + (char)key + " Integer Value: " + key);
      }

      return true;

}
}

Alittlelost · Feb 21st, 2008, 3:39 PM

I've now got the ball being reset after it gets passed the paddle (not that it even hits off it but still). so it resets back to a random y coordinate at the same x coordinate. I've also included a "computer score" which is updated each time the ball goes past the paddle.

Has anybody ne ideas on the collision detection, i am quickly running out of ideas and none of em seem to work. This is the updated code, please HELP!!!!

(Toggle Plain Text)

import java.applet.*;
import java.awt.*;   
import java.util.*;  
import java.math.*;  


public class Pong extends Applet implements Runnable
{
	/////BALL/////
	int xball = 590; 
	int	yball = 100; 
	int	radius = 20; 
	int	x_speed;
	int	y_speed;
	int xc,yc;
	
	/////PADDLE////
	int xpad = 100; 
	int	ypad = 100; 
	int	x_speed1; 
	int	y_speed1;
	int xpadc,ypadc;
	
	/////MISC///////////////
	int	appletsize_x = 800; 
	int	appletsize_y = 600;
	int playerscore;
	int i,j;
	final int PI = 3.14;
	private Image dbImage;
	private Graphics dbg;
	
	Random rnd = new Random();
	
	int ballarea = PI*(radius*radius);
	
	
	public void init()
	{
		setBackground (Color.blue);
	}
	
	public void start ()
	{
		
		Thread th = new Thread (this);
		
		th.start ();
	}
	
	public void stop()
	{

	}
	
	public void destroy()
	{

	}
	
	public void run ()
	{
		
		Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
		
		while (true)
		{
			if (xball > appletsize_x - radius)
			{
				x_speed = +10; 
			}
	
			else if (xball < radius)
			{
				x_speed = +10; 
			}
			
			else if (yball > appletsize_y - radius)
			{
				y_speed = -10;  
			}
			
			else if (yball < radius)
			{
				y_speed = +10;
			}
			
			else if (xball < xpad-50)
			{
				xball = 700;
				yball = rnd.nextInt(600);
				playerscore++;
				yc = yball;
			}
			else {}
			
			xball += x_speed;
			yball += y_speed;
			
			////////////////////////////////////////////////////////
			
			if (ypad > appletsize_y - radius*4)
			{
				y_speed1 = -10;  
			}
			
			else if (ypad < radius)
			{
				y_speed1 = 10;
			}
			
			
			xpad += x_speed1;
			ypad += y_speed1;

			
			
			repaint();

			try
			{
				Thread.sleep (20);
			}
			
			catch (InterruptedException ex)
			{
				
			}

			Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
		}
	}
	
	public void update (Graphics g)
	{
		
		if (dbImage == null)
		{
			dbImage = createImage (this.getSize().width, this.getSize().height);
			dbg = dbImage.getGraphics ();
		}

		
		dbg.setColor (getBackground ());
		dbg.fillRect (0, 0, this.getSize().width, this.getSize().height);

		
		dbg.setColor (getForeground());
		paint (dbg);

		
		g.drawImage (dbImage, 0, 0, this);
	}
	
	public void paint (Graphics g)
	{
		g.setColor  (Color.red);

		g.fillOval  (xball - radius, yball - radius, 2 * radius, 2 * radius);
		
		g.setColor  (Color.green);

		g.fillRect  (xpad - radius, ypad - radius, 2 * radius, 2 * radius+50);
		
		g.setColor (Color.white);
		
		g.drawString("Computer Score = " + playerscore,0,10);
		
	}
	
	
	public boolean keyDown (Event e, int key)
	{
      
      if (key == 32)
      {
            x_speed = -10;
            y_speed = +10;
      }

      else if (key == 113)// key 'Q' = move paddle up
      {
            x_speed1 = 0;
            y_speed1 = -10;
      }
      
      else if (key == 97)// key 'A' = move paddle down
      {
            x_speed1 = 0;
            y_speed1 = +10;
            //System.out.println("ycoord: " + ypad);
            //System.out.println("xcoord: " + xpad);
      }
      
      else
      {
            System.out.println ("Charakter: " + (char)key + " Integer Value: " + key);
      }

      return true;

	}
}//end class

import java.applet.*;
import java.awt.*;   
import java.util.*;  
import java.math.*;  


public class Pong extends Applet implements Runnable
{
	/////BALL/////
	int xball = 590; 
	int	yball = 100; 
	int	radius = 20; 
	int	x_speed;
	int	y_speed;
	int xc,yc;
	
	/////PADDLE////
	int xpad = 100; 
	int	ypad = 100; 
	int	x_speed1; 
	int	y_speed1;
	int xpadc,ypadc;
	
	/////MISC///////////////
	int	appletsize_x = 800; 
	int	appletsize_y = 600;
	int playerscore;
	int i,j;
	final int PI = 3.14;
	private Image dbImage;
	private Graphics dbg;
	
	Random rnd = new Random();
	
	int ballarea = PI*(radius*radius);
	
	
	public void init()
	{
		setBackground (Color.blue);
	}
	
	public void start ()
	{
		
		Thread th = new Thread (this);
		
		th.start ();
	}
	
	public void stop()
	{

	}
	
	public void destroy()
	{

	}
	
	public void run ()
	{
		
		Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
		
		while (true)
		{
			if (xball > appletsize_x - radius)
			{
				x_speed = +10; 
			}
	
			else if (xball < radius)
			{
				x_speed = +10; 
			}
			
			else if (yball > appletsize_y - radius)
			{
				y_speed = -10;  
			}
			
			else if (yball < radius)
			{
				y_speed = +10;
			}
			
			else if (xball < xpad-50)
			{
				xball = 700;
				yball = rnd.nextInt(600);
				playerscore++;
				yc = yball;
			}
			else {}
			
			xball += x_speed;
			yball += y_speed;
			
			////////////////////////////////////////////////////////
			
			if (ypad > appletsize_y - radius*4)
			{
				y_speed1 = -10;  
			}
			
			else if (ypad < radius)
			{
				y_speed1 = 10;
			}
			
			
			xpad += x_speed1;
			ypad += y_speed1;

			
			
			repaint();

			try
			{
				Thread.sleep (20);
			}
			
			catch (InterruptedException ex)
			{
				
			}

			Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
		}
	}
	
	public void update (Graphics g)
	{
		
		if (dbImage == null)
		{
			dbImage = createImage (this.getSize().width, this.getSize().height);
			dbg = dbImage.getGraphics ();
		}

		
		dbg.setColor (getBackground ());
		dbg.fillRect (0, 0, this.getSize().width, this.getSize().height);

		
		dbg.setColor (getForeground());
		paint (dbg);

		
		g.drawImage (dbImage, 0, 0, this);
	}
	
	public void paint (Graphics g)
	{
		g.setColor  (Color.red);

		g.fillOval  (xball - radius, yball - radius, 2 * radius, 2 * radius);
		
		g.setColor  (Color.green);

		g.fillRect  (xpad - radius, ypad - radius, 2 * radius, 2 * radius+50);
		
		g.setColor (Color.white);
		
		g.drawString("Computer Score = " + playerscore,0,10);
		
	}
	
	
	public boolean keyDown (Event e, int key)
	{
      
      if (key == 32)
      {
            x_speed = -10;
            y_speed = +10;
      }

      else if (key == 113)// key 'Q' = move paddle up
      {
            x_speed1 = 0;
            y_speed1 = -10;
      }
      
      else if (key == 97)// key 'A' = move paddle down
      {
            x_speed1 = 0;
            y_speed1 = +10;
            //System.out.println("ycoord: " + ypad);
            //System.out.println("xcoord: " + xpad);
      }
      
      else
      {
            System.out.println ("Charakter: " + (char)key + " Integer Value: " + key);
      }

      return true;

	}
}//end class

mrynit · Feb 28th, 2008, 12:58 AM

You could try to use some triginomitry by using sin and cos with right triangles.

colin mac · Feb 28th, 2008, 6:16 AM

Possibly by using the distance formula. If the distance between the paddle and ball is less than such a number, you've got a collision. But I guess it depends on the coordinate system you're using.
http://www.purplemath.com/modules/distform.htm

Wizard1988 · Feb 28th, 2008, 7:27 AM

There is a couple of ways you can do this. First I would simply check if the balls x coordinate is less than (x_paddle_position + paddle_width).

You can get more info here: http://www.edenwaith.com/products/pi.../collision.php

Feb 20th, 2008, 6:02 PM	#1
Alittlelost Newbie Join Date: Jan 2008 Location: Belfast, Northern Ireland Posts: 7 Rep Power: 0	2d Pong HELP!! Hey everyone, I tried looking around pretty much everywhere i could think of but i havnt been able to come up with a solution to my problem, which ill explain in a minute. This is my first time making any sort of videogame so im a complete beginner to some of the methods involved. I am attempting to make a 2d pong java applet. So far I have the background colored. The paddle and ball on the screen. User input works to move the paddle up and down. The ball moves randomly and resets to its original position after reaching a certain x-coordinate (best way i could think of). The ball also bounces off the right,top and bottom 'walls'. This idea of the game is basically a single player game of squash, so that for now, i can avoid AI. Sorry for going on so much, but my problem is that I cannot find a way to create collsion detection between the paddle (a rectangle made with g.fillRect) and the ball (made with g.fillOval). I have tried using the Rectangle class and creating an intersects boolean but with no success, my code compiled but it seemed to have no effect. Here is my code, thanks a lot for any help and thanks for reading this. (Toggle Plain Text) import java.applet.; import java.awt.; import java.util.; import java.math.; public class Ball extends Applet implements Runnable { int x_pos = 590, y_pos = 100, radius = 20, appletsize_x = 800, appletsize_y = 600, x_speed=0, y_speed=0; int x_pos1 = 100, y_pos1 = 100, x_speed1, y_speed1; int limit = 100; Random rnd = new Random(); private Image dbImage; private Graphics dbg; public void init() { setBackground (Color.blue); } public void start () { Thread th = new Thread (this); th.start (); } public void stop() { } public void destroy() { } public void run () { Thread.currentThread().setPriority(Thread.MIN_PRIORITY); while (true) { if (x_pos > appletsize_x - radius) { x_speed = -10; } else if (x_pos < radius) { x_speed = +10; } else if (y_pos > appletsize_y - radius) { y_speed = -10; } else if (y_pos < radius) { y_speed = +10; } else if (x_pos < x_pos1-50)/////////////////////////// { x_pos = 590; y_pos = rnd.nextInt(600); } x_pos += x_speed; y_pos += y_speed; if (x_pos1 > appletsize_x - radius) { x_speed1 = -10; } else if (x_pos1 < radius) { x_speed1 = +10; } else if (y_pos1 > appletsize_y - radius4) { y_speed1 = -10; } else if (y_pos1 < radius) { y_speed1 = +10; } x_pos1 += x_speed1; y_pos1 += y_speed1; repaint(); try { Thread.sleep (20); } catch (InterruptedException ex) { } Thread.currentThread().setPriority(Thread.MAX_PRIORITY); } } public void update (Graphics g) { if (dbImage == null) { dbImage = createImage (this.getSize().width, this.getSize().height); dbg = dbImage.getGraphics (); } dbg.setColor (getBackground ()); dbg.fillRect (0, 0, this.getSize().width, this.getSize().height); dbg.setColor (getForeground()); paint (dbg); g.drawImage (dbImage, 0, 0, this); } public void paint (Graphics g) { g.setColor (Color.red); g.fillOval (x_pos - radius, y_pos - radius, 2 radius, 2 * radius); g.setColor (Color.green); g.fillRect (x_pos1 - radius, y_pos1 - radius, 2 * radius, 2 * radius+50); } public boolean keyDown (Event e, int key) { if (key == Event.LEFT) { x_speed = -10; y_speed = 0; } else if (key == Event.RIGHT) { x_speed = 10; y_speed = 0; } else if (key == Event.DOWN) { y_speed = 10; x_speed = 0; } else if (key == Event.UP) { y_speed = -10; x_speed = 0; } else if (key == 32) { x_speed = -10; y_speed = +10; } else { System.out.println ("Character: " + (char)key + " Integer Value: " + key); } if (key == 113) { x_speed1 = 0; y_speed1 = -10; } else if (key == 97) { x_speed1 = 0; y_speed1 = +10; } //else if (key == 32) //{ // x_speed1 = 0; // y_speed1 = 0; //} else { System.out.println ("Character: " + (char)key + " Integer Value: " + key); } return true; } } import java.applet.; import java.awt.; import java.util.; import java.math.; public class Ball extends Applet implements Runnable { int x_pos = 590, y_pos = 100, radius = 20, appletsize_x = 800, appletsize_y = 600, x_speed=0, y_speed=0; int x_pos1 = 100, y_pos1 = 100, x_speed1, y_speed1; int limit = 100; Random rnd = new Random(); private Image dbImage; private Graphics dbg; public void init() { setBackground (Color.blue); } public void start () { Thread th = new Thread (this); th.start (); } public void stop() { } public void destroy() { } public void run () { Thread.currentThread().setPriority(Thread.MIN_PRIORITY); while (true) { if (x_pos > appletsize_x - radius) { x_speed = -10; } else if (x_pos < radius) { x_speed = +10; } else if (y_pos > appletsize_y - radius) { y_speed = -10; } else if (y_pos < radius) { y_speed = +10; } else if (x_pos < x_pos1-50)/////////////////////////// { x_pos = 590; y_pos = rnd.nextInt(600); } x_pos += x_speed; y_pos += y_speed; if (x_pos1 > appletsize_x - radius) { x_speed1 = -10; } else if (x_pos1 < radius) { x_speed1 = +10; } else if (y_pos1 > appletsize_y - radius4) { y_speed1 = -10; } else if (y_pos1 < radius) { y_speed1 = +10; } x_pos1 += x_speed1; y_pos1 += y_speed1; repaint(); try { Thread.sleep (20); } catch (InterruptedException ex) { } Thread.currentThread().setPriority(Thread.MAX_PRIORITY); } } public void update (Graphics g) { if (dbImage == null) { dbImage = createImage (this.getSize().width, this.getSize().height); dbg = dbImage.getGraphics (); } dbg.setColor (getBackground ()); dbg.fillRect (0, 0, this.getSize().width, this.getSize().height); dbg.setColor (getForeground()); paint (dbg); g.drawImage (dbImage, 0, 0, this); } public void paint (Graphics g) { g.setColor (Color.red); g.fillOval (x_pos - radius, y_pos - radius, 2 radius, 2 * radius); g.setColor (Color.green); g.fillRect (x_pos1 - radius, y_pos1 - radius, 2 * radius, 2 * radius+50); } public boolean keyDown (Event e, int key) { if (key == Event.LEFT) { x_speed = -10; y_speed = 0; } else if (key == Event.RIGHT) { x_speed = 10; y_speed = 0; } else if (key == Event.DOWN) { y_speed = 10; x_speed = 0; } else if (key == Event.UP) { y_speed = -10; x_speed = 0; } else if (key == 32) { x_speed = -10; y_speed = +10; } else { System.out.println ("Character: " + (char)key + " Integer Value: " + key); } if (key == 113) { x_speed1 = 0; y_speed1 = -10; } else if (key == 97) { x_speed1 = 0; y_speed1 = +10; } //else if (key == 32) //{ // x_speed1 = 0; // y_speed1 = 0; //} else { System.out.println ("Character: " + (char)key + " Integer Value: " + key); } return true; } }

Feb 21st, 2008, 3:39 PM	#2
Alittlelost Newbie Join Date: Jan 2008 Location: Belfast, Northern Ireland Posts: 7 Rep Power: 0	Re: 2d Pong HELP!! I've now got the ball being reset after it gets passed the paddle (not that it even hits off it but still). so it resets back to a random y coordinate at the same x coordinate. I've also included a "computer score" which is updated each time the ball goes past the paddle. Has anybody ne ideas on the collision detection, i am quickly running out of ideas and none of em seem to work. This is the updated code, please HELP!!!! (Toggle Plain Text) import java.applet.; import java.awt.; import java.util.; import java.math.; public class Pong extends Applet implements Runnable { /////BALL///// int xball = 590; int yball = 100; int radius = 20; int x_speed; int y_speed; int xc,yc; /////PADDLE//// int xpad = 100; int ypad = 100; int x_speed1; int y_speed1; int xpadc,ypadc; /////MISC/////////////// int appletsize_x = 800; int appletsize_y = 600; int playerscore; int i,j; final int PI = 3.14; private Image dbImage; private Graphics dbg; Random rnd = new Random(); int ballarea = PI(radiusradius); public void init() { setBackground (Color.blue); } public void start () { Thread th = new Thread (this); th.start (); } public void stop() { } public void destroy() { } public void run () { Thread.currentThread().setPriority(Thread.MIN_PRIORITY); while (true) { if (xball > appletsize_x - radius) { x_speed = +10; } else if (xball < radius) { x_speed = +10; } else if (yball > appletsize_y - radius) { y_speed = -10; } else if (yball < radius) { y_speed = +10; } else if (xball < xpad-50) { xball = 700; yball = rnd.nextInt(600); playerscore++; yc = yball; } else {} xball += x_speed; yball += y_speed; //////////////////////////////////////////////////////// if (ypad > appletsize_y - radius4) { y_speed1 = -10; } else if (ypad < radius) { y_speed1 = 10; } xpad += x_speed1; ypad += y_speed1; repaint(); try { Thread.sleep (20); } catch (InterruptedException ex) { } Thread.currentThread().setPriority(Thread.MAX_PRIORITY); } } public void update (Graphics g) { if (dbImage == null) { dbImage = createImage (this.getSize().width, this.getSize().height); dbg = dbImage.getGraphics (); } dbg.setColor (getBackground ()); dbg.fillRect (0, 0, this.getSize().width, this.getSize().height); dbg.setColor (getForeground()); paint (dbg); g.drawImage (dbImage, 0, 0, this); } public void paint (Graphics g) { g.setColor (Color.red); g.fillOval (xball - radius, yball - radius, 2 radius, 2 * radius); g.setColor (Color.green); g.fillRect (xpad - radius, ypad - radius, 2 * radius, 2 * radius+50); g.setColor (Color.white); g.drawString("Computer Score = " + playerscore,0,10); } public boolean keyDown (Event e, int key) { if (key == 32) { x_speed = -10; y_speed = +10; } else if (key == 113)// key 'Q' = move paddle up { x_speed1 = 0; y_speed1 = -10; } else if (key == 97)// key 'A' = move paddle down { x_speed1 = 0; y_speed1 = +10; //System.out.println("ycoord: " + ypad); //System.out.println("xcoord: " + xpad); } else { System.out.println ("Charakter: " + (char)key + " Integer Value: " + key); } return true; } }//end class import java.applet.; import java.awt.; import java.util.; import java.math.; public class Pong extends Applet implements Runnable { /////BALL///// int xball = 590; int yball = 100; int radius = 20; int x_speed; int y_speed; int xc,yc; /////PADDLE//// int xpad = 100; int ypad = 100; int x_speed1; int y_speed1; int xpadc,ypadc; /////MISC/////////////// int appletsize_x = 800; int appletsize_y = 600; int playerscore; int i,j; final int PI = 3.14; private Image dbImage; private Graphics dbg; Random rnd = new Random(); int ballarea = PI(radiusradius); public void init() { setBackground (Color.blue); } public void start () { Thread th = new Thread (this); th.start (); } public void stop() { } public void destroy() { } public void run () { Thread.currentThread().setPriority(Thread.MIN_PRIORITY); while (true) { if (xball > appletsize_x - radius) { x_speed = +10; } else if (xball < radius) { x_speed = +10; } else if (yball > appletsize_y - radius) { y_speed = -10; } else if (yball < radius) { y_speed = +10; } else if (xball < xpad-50) { xball = 700; yball = rnd.nextInt(600); playerscore++; yc = yball; } else {} xball += x_speed; yball += y_speed; //////////////////////////////////////////////////////// if (ypad > appletsize_y - radius4) { y_speed1 = -10; } else if (ypad < radius) { y_speed1 = 10; } xpad += x_speed1; ypad += y_speed1; repaint(); try { Thread.sleep (20); } catch (InterruptedException ex) { } Thread.currentThread().setPriority(Thread.MAX_PRIORITY); } } public void update (Graphics g) { if (dbImage == null) { dbImage = createImage (this.getSize().width, this.getSize().height); dbg = dbImage.getGraphics (); } dbg.setColor (getBackground ()); dbg.fillRect (0, 0, this.getSize().width, this.getSize().height); dbg.setColor (getForeground()); paint (dbg); g.drawImage (dbImage, 0, 0, this); } public void paint (Graphics g) { g.setColor (Color.red); g.fillOval (xball - radius, yball - radius, 2 radius, 2 * radius); g.setColor (Color.green); g.fillRect (xpad - radius, ypad - radius, 2 * radius, 2 * radius+50); g.setColor (Color.white); g.drawString("Computer Score = " + playerscore,0,10); } public boolean keyDown (Event e, int key) { if (key == 32) { x_speed = -10; y_speed = +10; } else if (key == 113)// key 'Q' = move paddle up { x_speed1 = 0; y_speed1 = -10; } else if (key == 97)// key 'A' = move paddle down { x_speed1 = 0; y_speed1 = +10; //System.out.println("ycoord: " + ypad); //System.out.println("xcoord: " + xpad); } else { System.out.println ("Charakter: " + (char)key + " Integer Value: " + key); } return true; } }//end class

Feb 28th, 2008, 12:58 AM	#3
mrynit Hobbyist Programmer Join Date: Mar 2006 Location: WA, USA Posts: 332 Rep Power: 3	Re: 2d Pong HELP!! You could try to use some triginomitry by using sin and cos with right triangles. __________________ i dont know much about programming but i try to help

Feb 28th, 2008, 6:16 AM	#4
colin mac Newbie Join Date: Nov 2007 Location: Ireland Posts: 18 Rep Power: 0	Re: 2d Pong HELP!! Possibly by using the distance formula. If the distance between the paddle and ball is less than such a number, you've got a collision. But I guess it depends on the coordinate system you're using. http://www.purplemath.com/modules/distform.htm

Feb 28th, 2008, 7:27 AM	#5
Wizard1988 Professional Programmer Join Date: Oct 2005 Location: Chitown Posts: 417 Rep Power: 3	Re: 2d Pong HELP!! There is a couple of ways you can do this. First I would simply check if the balls x coordinate is less than (x_paddle_position + paddle_width). You can get more info here: http://www.edenwaith.com/products/pi.../collision.php __________________ JG-Webdesign

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
2D Graphics in Java	truBlu	Java	5	Feb 3rd, 2008 2:49 PM
2d array	michelle_789	C	3	Nov 27th, 2007 8:23 AM
Original Pong circuit	Klarre	Coder's Corner Lounge	3	Aug 21st, 2006 10:30 PM
Pong game complete	teencoder	Show Off Your Open Source Projects	6	Aug 9th, 2006 2:27 PM
Pong AI	Markpy	Delphi	1	Oct 13th, 2005 5:50 AM

Programming Forums > Application Development > Java

2d Pong HELP!!