help with pong collision
I am working on a pong-like game for a project... and i am having some trouble with collision checks... again.
Here is our code so far, the problem is that the ball seems to be stopping completely when it is aligned with a paddle on the Y axis (even if it is at the center of the screen)
import java.applet.*;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
publicclass TestAppletextends Appletimplements Runnable
{
//Paddle dimensions
int PaddleHeight = 50;
int PaddleWidth = 10;
//Other variables
boolean isStop =true;
int[] theKeys =newint[256];//Array with one element representing each key
Random Rand =new Random();
int bounces = 0;
boolean isAI2 =false;
boolean isAI1 =false;
ArrayList <Ball> TheBalls =new ArrayList <Ball>();
Paddle[] ThePaddles =new Paddle[2];
//Player scores
int Score1 = 0;
int Score2 = 0;
private Image dblimage;
private Graphics dbg;
publicvoid init()
{
//Set Background color to black
setBackground(Color.black);
}
publicvoid start()
{
//Define new thread
Thread th =new Thread(this);
//Start the new thread
th.start();
for(int z=0; z<256; z++)
theKeys[z] = 0;//Set all keys to default position (released)
enableEvents(AWTEvent.KEY_EVENT_MASK);
ThePaddles[0]=(new Paddle(true, PaddleHeight, PaddleWidth, 10, this.getWidth(), this.getHeight(),'w','s'));
ThePaddles[1]=(new Paddle(false, PaddleHeight, PaddleWidth, 10, this.getWidth(), this.getHeight(),'8','5'));
TheBalls.add(new Ball(this.getHeight(), this.getWidth()));
TheBalls.get(0).AddPaddle(ThePaddles[0]);
TheBalls.get(0).AddPaddle(ThePaddles[1]);
}
publicvoid run ()
{
//Minimize thread priority
Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
while (true)
{
for(int i=0; i<ThePaddles.length; i++)
{
if(isKeyPress(87))
{
ThePaddles[i].Move(1);
}
elseif(isKeyPress(83))
{
ThePaddles[i].Move(-1);
}
}
if(isKeyPress(32))
{
for(int x=0; x >< TheBalls.size(); x++)
TheBalls.get(x).Start();
isStop =false;
bounces = 0;
}
for(int i=0; i<TheBalls.size(); i++)
{
TheBalls.get(i).Move();
String scored = TheBalls.get(i).IsScore();
if(scored =="Player 1")
{
Score1++;
break;
}
elseif(scored =="Player 2")
{
Score2++;
break;
}
}
repaint();
try
{
Thread.sleep (20);
}
catch (InterruptedException ex)
{
// do nothing
}
Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
}
}
publicvoid paint(Graphics g)
{
//set color
g.setColor(Color.green);
for(Ball temp : TheBalls)
{
int[] tempfo = temp.BallInfo();
g.fillOval(tempfo[0], tempfo[1], tempfo[2], tempfo[3]);
}
for(Paddle temp: ThePaddles)
{
int[] PadTemp = temp.PaddleData();
g.fillRect(PadTemp[0], PadTemp[1], PadTemp[2], PadTemp[3]);
}
//paint player 1 score
g.drawString("Player 1 score: "+Score1, 10, 50);
//paint player 2 score
g.drawString("Player 2 score: "+Score2, 400, 50);
//paint current bounce count
g.drawString("Bounces: "+bounces, 250, 50);
g.drawString(""+ThePaddles[0].GetUp(), 100, 100);
g.drawString(""+ThePaddles[0].GetDown(), 100, 400);
g.drawString(""+ThePaddles[1].GetUp(), 200, 100);
g.drawString(""+ThePaddles[1].GetDown(), 200, 400);
g.drawString(""+TheBalls.get(0).Collide(), 250, 250);
g.drawLine(ThePaddles[0].getX(), ThePaddles[0].GetTop(), ThePaddles[0].getX()-500, ThePaddles[0].GetTop());
}
publicvoid update (Graphics g)
{
// initialize buffer
if (dblimage ==null)
{
dblimage = createImage (this.getSize().width, this.getSize().height);
dbg = dblimage.getGraphics ();
}
// clear screen in background
dbg.setColor (getBackground ());
dbg.fillRect (0, 0, this.getSize().width, this.getSize().height);
// draw elements in background
dbg.setColor (getForeground());
paint (dbg);
// draw image on the screen
g.drawImage (dblimage, 0, 0,this);
}
publicvoid processKeyEvent(KeyEvent ev)
{
int keycode = (ev.getKeyCode()&0xff);
if (ev.getID() == KeyEvent.KEY_PRESSED)
{
theKeys[keycode] = 1;//1 Represents key is pressed
}
elseif (ev.getID() == KeyEvent.KEY_RELEASED)
{
theKeys[keycode] = 0;//0 Represents key is not pressed
}
repaint();
}
//Checks if a given key is pressed
publicboolean isKeyPress(int theKey)
{
return (theKeys[theKey] != 0);
}
//Checks if a given key is released
publicboolean isKeyRel(int theKey)
{
return(theKeys[theKey] == 0);
}
}
class Paddle
{
privateint
XPos,
YPos,
Width,
Height,
Speed,
AppletHeight,
AppletWidth,
Down,
Up;
boolean
LeftSide;
public Paddle(boolean LeftSide,int Height,int Width,int Speed,int AppletWidth,int AppletHeight,char Up,char Down)
{
this.AppletHeight = AppletHeight;
this.AppletWidth = AppletWidth;
YPos = AppletHeight/2;
this.Height = Height;
this.Width = Width;
this.Speed = Speed;
this.LeftSide = LeftSide;
if(LeftSide)
this.XPos = 15;
else
this.XPos = AppletWidth-25;
Character UpChar =new Character(Up);
Character DownChar =new Character(Down);
this.Up = UpChar.charValue();
this.Down = DownChar.charValue();
}
publicvoid Move(int x)
{
if(x > 0)
{
YPos -= Speed;
}
else
YPos += Speed;
}
publicint GetTop()
{
return YPos - Height/2;
}
publicint GetBottom()
{
return YPos + Height/2;
}
publicint GetUp()
{
return Up;
}
publicint GetDown()
{
return Down;
}
publicint getX()
{
return XPos;
}
publicint getY()
{
return YPos;
}
publicint GetHeight()
{
return Height;
}
publicint GetWidth()
{
return Width;
}
publicint[] PaddleData()
{
if(LeftSide)
returnnewint[]{XPos+Width/2, YPos-Height/2, Width, Height};
returnnewint[]{XPos-Width/2, YPos-Height/2, Width, Height};
}
}
class Ball
{
privateint
XPos,
XSpeed,
YPos,
YSpeed,
Radius,
MaxSpeed,
Height,
Width;
privateboolean
IsStill;
private ArrayList <Paddle>
ThePaddles=new ArrayList <Paddle>();
private Random Rand=new Random();
public Ball(int Width,int Height)
{
this.ThePaddles=ThePaddles;
this.Height=Height;
this.Width=Width;
XPos=Width/2;
YPos=Height/2;
IsStill=true;
MaxSpeed=9;
Radius=10;
ChangeAngle();
}
publicvoid AddPaddle(Paddle temp)
{
ThePaddles.add(temp);
}
publicint[] BallInfo()
{
returnnewint[]{XPos-Radius, YPos-Radius, 2*Radius, 2*Radius};
}
publicvoid Start()
{
IsStill =false;
}
publicint getX()
{
return XPos;
}
publicint getY()
{
return YPos;
}
publicint getRad()
{
return Radius;
}
publicvoid RevX()
{
XSpeed *= -1;
}
publicint getXSp()
{
return XSpeed;
}
publicint getYSp()
{
return YSpeed;
}
publicboolean isNeg()
{
if(XSpeed < 0)
returntrue;
returnfalse;
}
//Generates a random trajectory for the ball
publicvoid ChangeAngle()
{
int Num, Opp;
Num= Rand.nextInt(MaxSpeed)+1;
Opp = MaxSpeed-Num;
XSpeed = ((XSpeed>0)?1:-1)*Num;
YSpeed = ((Rand.nextInt(2)==0)?1:-1)*Opp;
}
publicboolean Collide()
{
boolean collid=false;
for(Paddle i: ThePaddles)
{
if(YPos >= i.GetTop() && YPos <= i.GetBottom())
{
if(i.LeftSide)
collid = (((XPos - Radius) <= (i.getX() + i.GetWidth())));
if(!collid)
collid = (((XPos + Radius) >= (i.getX() - i.GetWidth())));
}
}
if(!collid)
collid = ((YPos<=0 && YSpeed < 0) || (YPos>=Height && YSpeed > 0));
return collid;
}
public String IsScore()
{
if(XPos >= Width)
{
XPos = Width/2;
YPos = Height/2;
IsStill =true;
return"Player 1";
}
if(XPos <= 0)
{
XPos = Width/2;
YPos = Height/2;
IsStill =true;
return"Player 2";
}
return"";
}
publicvoid Move()
{
boolean temp =false;
for(int i=0; i<=Math.abs(XSpeed); i++)
{
if((Collide()) && !temp)
{
RevX();
ChangeAngle();
temp =true;
break;
}
XPos = ((XSpeed>0)?XPos+1:XPos-1);
}
temp =false;
for(int i=0; i<=Math.abs(YSpeed); i++)
{
if((Collide()) && !temp)
{
YSpeed *= -1;
temp =true;
break;
}
YPos = ((YSpeed>0)?YPos+1:YPos-1);
}
}
}
