Erase earlier defined objects

fre3zr

Hello dear community, First of all, I'd like to excuse for any English mistakes I make, because I'm from switzerland ;).

Well, about a week ago we started to learn Processing 2.1 in our school, enthusastic as I am I wachted some tutorials at home and planned to do a little game, a simple Ping-Pong game.

I have designed a main menu, where you can select between "Start game", "Settings", and "Exit". I have already programmed the start- and the exit-button, like this (I have shortened it a bit for a more viewable sight):

 void button () {
      if ((mouseX >= xPos) && (mouseX <= xPos + xSize) && (mouseY >= yPos) && (mouseY <= yPos + ySize)) {
        colr = color(80,80,80);
        if (mousePressed) {
          doAction = true;
        }
      }

      noStroke();
      fill (colr);
      smooth();
      rect (xPos, yPos, xSize, ySize, rectRound);

      textFont (buttonFont, fontSize);
      fill (textColr);
      textAlign(CENTER);
      text (text, xPos + (xSize/2), yPos + textyShift);

      if (doAction) {
        startGame();
      }
    }

However, in the startGame() function I have written a background(0);, because I read in some other posts that this will erase everything on the screen. But this is not true haha, when I click on "Start game", the background turns black, the "Start game"-butten disappears, but the ones for settings and exit still stay on the screen.

I have no idea what to do to make them disapper, and I hope someone can help me :).

Have a nice day everyone, fre3zr

GoToLoop

A background(0);, or even clear(), indeed clears whole canvas w/ black color!
We do that in order to get a clean slate to render animated graphics in different positions w/o having traces of previous 1s.

... the "Start game" button disappears, but the ones for "Settings" and "Exit" still stay on the screen.

Well, if you keep redrawing them, of course they will stick on! :-&
You gotta have state flags to denote which is drawn or not!

static final int MENU_STATE = 0;
static final int PLAY_STATE = 1;
static final int HALT_STATE = 2;
static final int OVER_STATE = 3;

static int state = MENU_STATE;

So, when program starts, it gotta display its menu. So state = MENU_STATE;.
Now, when the action starts, you change state to PLAY_STATE. And so on! :P
Of course, you gotta make all of the pieces of your program to obey that state variable! L-)

Some performance bits: (:|
If your program has the same smooth(), textAlign(), textFont() throughout, place those within setup()!

fre3zr

Oooh that opens new possibilites . haha :D

Thank you so much, I was really wondering about if there is a way to pause functions. :)

fre3zr

Oh, and with your answer to my first question, the next comes up. ^^

I don't understand how to use those static int states. I have declared a "static final int MENU_STATE = 0;" and a "static final int PLAY_STATE = 0;" at the top of the program, now how can I give those states to my different functions?

Have I to define each function with "static int state = MENU_STATE;" and then call the MENU_STATE in my draw() function or what?

Because I'm new to that language and it's the first language I try to use more detailled, and because I'm not very into OOP yet, it's quite difficult for me to understand haha, sorry for that!

With kind regards, fre3zr