Coding problem in my game

Processing Coding Questions
1

Hello. I have once again stumbled across a problem which I couldn’t resolve myself. My Plank does interact with the ball, but only sometimes. And sometimes on the edge the ball just bursts through. I think the problem is somewhere in the Ball class move function. I also noticed it has something to do with the direction the ball is coming down. If you have time, I would really appreciate if someone checked the code and saw for themselves. The game is in the early stages and the code looks messy, but I will fix it later :).

color colbcg;
Plank myPlank;
Ball myBall;

void setup(){
  size(500,500);
  myPlank = new Plank();
  myBall = new Ball();
}
  

void draw(){
  background(colbcg);
  myPlank.display();
  myPlank.move();
  myBall.display();
  myBall.move();
}
class Ball{
  int xbpos;
  int ybpos;
  int bw;
  int bl;
  int xbspeed;
  int ybspeed;
  int bcol;
  
 
  Ball(){
    xbpos=width/2;
    ybpos=393;
    bw=width/50;
    bl=height/50;
    xbspeed=3;
    ybspeed=-3;
    bcol=255;
    
  }
  void display(){
    ellipseMode(CENTER);
    noStroke();
    fill(bcol);
    ellipse(xbpos,ybpos,bw,bl);
  }
  void move(){
    ybpos+=ybspeed;
    xbpos+=xbspeed;
 
 
  if(xbpos<5||xbpos>width-5){
    xbspeed*=-1;
    
  }if(ybpos<0+5||ybpos>height-5){
    ybspeed*=-1;
   
  }if(xbpos>myPlank.xpos-15 && xbpos<myPlank.xpos+15 && ybpos>myPlank.ypos-7.4){
    ybspeed*=-1;
    
    
  }
  
 }

}
class Plank{
  int xpos;
  int ypos;
  int l;
  int w;
  int col;
  
  Plank(){
   xpos = width/2;
   ypos = height-(height*1/5);
   l = width/10;
   w = height/100;
   col = 255;
  }
  
   void display() {
     rectMode(CENTER);
     fill(col);
     rect(xpos,ypos,l,w);
   }
   
   void move(){
     if(mousePressed&&mouseButton == LEFT){
       xpos = mouseX;
     }     
     if(xpos<0+l/2){
       xpos=0+l/2;
     }if(xpos>width-l/2){
       xpos=width-l/2;
     }
   }
}
2

Hi

Nice game I just remove &&mouseButton == LEFT on my tablet there is no mouse button option

if(mousePressed&&mouseButton == LEFT){

It’s working

color colbcg;
Plank myPlank;
Ball myBall;

void setup(){
  size(500,500);
  myPlank = new Plank();
  myBall = new Ball();
}
  

void draw(){
  background(colbcg);
  myPlank.display();
  myPlank.move();
  myBall.display();
  myBall.move();
}
class Ball{
  int xbpos;
  int ybpos;
  int bw;
  int bl;
  int xbspeed;
  int ybspeed;
  int bcol;
  
 
  Ball(){
    xbpos=width/2;
    ybpos=393;
    bw=width/50;
    bl=height/50;
    xbspeed=3;
    ybspeed=-3;
    bcol=255;
    
  }
  void display(){
    ellipseMode(CENTER);
    noStroke();
    fill(bcol);
    ellipse(xbpos,ybpos,bw,bl);
  }
  void move(){
    ybpos+=ybspeed;
    xbpos+=xbspeed;
 
 
  if(xbpos<5||xbpos>width-5){
    xbspeed*=-1;
    
  }if(ybpos<0+5||ybpos>height-5){
    ybspeed*=-1;
   
  }if(xbpos>myPlank.xpos-15 && xbpos<myPlank.xpos+15 && ybpos>myPlank.ypos-7.4){
    ybspeed*=-1;
    
    
  }
  
 }

}
class Plank{
  int xpos;
  int ypos;
  int l;
  int w;
  int col;
  
  Plank(){
   xpos = width/2;
   ypos = height-(height*1/5);
   l = width/10;
   w = height/100;
   col = 255;
  }
  
   void display() {
     rectMode(CENTER);
     fill(col);
     rect(xpos,ypos,l,w);
   }
   
   void move(){
     if(mousePressed ){
       xpos = mouseX;
     }     
     if(xpos<0+l/2){
       xpos=0+l/2;
     }if(xpos>width-l/2){
       xpos=width-l/2;
     }
   }
}
4

I don’t like this expression although we see it in the examples and everywhere.

The reason is this: whenever the ball stays in the reverse area so that the expression is executed twice, the ball has the previous (wrong) direction again. Bad.
This can lead to stuttering of the ball (or leaving of the ball).

Instead I prefer the expression

ybspeed=abs(ybspeed); OR

ybspeed= - abs(ybspeed);

which is either always positive or always negative.

(Same for xbspeed)

This means even if the ball remains in the reverse
zone the outcome stays stable.

This means that you have to separate all ifs with
|| in it into two separate ifs.

Also at the paddle use ybspeed=-abs(ybspeed);

1 Like
5

Here you check the lower screen border; I think you have the south reflection check at the paddle and should not be repeated here.

1 Like
6

Here you assume a width of the plank = 30,
but it’s 50 !

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7

Hello @MaxU89,

Scrutinize this code snippet:

  //if(xbpos>myPlank.xpos-15 && xbpos<myPlank.xpos+15 && ybpos>myPlank.ypos-7.4){
    //ybspeed*=-1;
  
  // +y direction
  if(ybspeed>0 &&
     xbpos>myPlank.xpos-50 &&  // pl = 100
     xbpos<myPlank.xpos+50 &&
     
     ybpos>myPlank.ypos-20/2 -10 &&  // bw = 20 pw = 20
     ybpos<myPlank.ypos)
       {
       // set start of ybpos for new direction:
       ybpos = myPlank.ypos-20/2-10; // bw = 20 pw = 20
       ybspeed*=-1;
      //My code was something like this:
      //dir = -1;
      //speed = 3; // This was already set
      //ybspeed = dir*speed;
       }

  // -y direction
  
  // Code required here...

I wrote a Pong from scratch without the classes.
I adapted my efforts into your code and it seemed to work.

:)

8

You are always the best great teacher

1 Like