Hi im trying to fill the applet i'm making with a random amount of rectangles at random positions, but in such a way that it does not fill up too much of the applet.

to do that i wrote this code, which is to be executed in the setup() function.

void buildTown(){
   int amountFilled = 0;
   while (amountFilled < ((width*height)/2.2)){
     int xlengte = int(random(5, 60));
     int x = int(random(1, width - xlengte - 5));
     int ybreedte = int(random(5, 60));
     int y = int(random(1, height - ybreedte - 5));
     addBuilding(x,y,x + xlengte,y + ybreedte);
     updatePixels();
     amountFilled = computeSpace();
   }
 }
 
 int computeSpace(){
   int returnvalue = 0;
   loadPixels();
   for(int i = 0; i < pixels.length; i++){
     if(pixels[i] == Cwall){returnvalue++;}
   }
   return returnvalue;
 }

the compiler now complains that there is a nullpointer exception in updatePixels(). Without updatePixels() it goes into an eternal loop, can anyone help me with what's going wrong here?

thanks in advance

it's ok to work with pixels[] inside setup(), since setup is the equivalent of draw being run the first time (and that's what it's for).

however you will need to use loadPixels() before ever messing with the pixels[] array.