NullPointException Error with string variables (Beginner)

Question

I'm trying to imitate a similar code seen here http://www.openprocessing.org/sketch/7050 but I seem to have gotten a little mixed up with the code. I'm trying to get the effect of the letters essentially drawing the posterized image of the picture. But I have getting a NullPointException and assume is has to do with how I'm initializing the string variables but i can't seem to find what I'm doing wrong.

The Error

Exception in thread "Animation Thread" java.lang.NullPointerException
    at processing.opengl.PGL.getString(PGL.java:1029)
    at processing.opengl.PGraphicsOpenGL.getGLParameters(PGraphicsOpenGL.java:6076)
    at processing.opengl.PGraphicsOpenGL.beginDraw(PGraphicsOpenGL.java:1547)
    at MLKpractice.letterfit(MLKpractice.java:147)
    at MLKpractice.draw(MLKpractice.java:98)
    at processing.core.PApplet.handleDraw(PApplet.java:2120)
    at processing.core.PGraphicsJava2D.requestDraw(PGraphicsJava2D.java:197)
    at processing.core.PApplet.run(PApplet.java:1998)
    at java.lang.Thread.run(Thread.java:680)

The program says the error is on line 127

lettersquare.beginDraw();

But I believe the error is somewhere above

PFont font;
String fontpath = "ArialMT-200.vlw";
int fontstart = 300;
int fontend = 8;
float fontsize = fontstart;
float fontsizedecrease = 0.97;
PImage bg;
PImage australia;
PImage austria;
String country1 = "australia.jpg";
String country2 = "austria.jpg";
String letters = "Australia";
char[] chars = new char[52];
int nchars = 0;
int iterations = 500;
int c = 0;
PGraphics letter,lettersquare,drawing;

void setup(){
  //initialize the sketch
  size(900,600);
  //background(255);
  //initialize the font
  //font = loadFont(fontpath);
  ///*
  for(int i=0;i<letters.length();i++){
    boolean found = false;
    char lc = letters.charAt(i);
    for(int j=0;j<nchars;j++){
      if(chars[j]==lc){
        found = true;
        break;
      }
    }
    if(!found) chars[nchars++] = lc;
  }
  chars = (char[]) subset(chars,0,nchars);
  font = createFont("Arial",200,true,chars);
  //*/
  textAlign(CENTER,CENTER);
  //load the image that will be filled with letters
  australia = loadImage(country1);
   austria = loadImage(country2);

  bg = loadImage("background.jpg");
  //posterize the image
  australia.filter(THRESHOLD,0.4);
  australia.filter(BLUR,3);
  australia.filter(THRESHOLD,0.6);
  //initialize the drawing buffers
  letter = createGraphics((int)fontsize,(int)fontsize,JAVA2D);
  lettersquare = createGraphics((int)fontsize,(int)fontsize,P2D);
  drawing = createGraphics(width,height,JAVA2D);
  drawing.beginDraw();
  drawing.background(255);
  // THIS STUPID THING NEEDS TO GO HERE!!!!
  drawing.image(bg,0,0);
  drawing.endDraw();
}

void draw(){

  if(floor(fontsize)>fontend&&c<letters.length()-1){
    if(!letterfit()){
      fontsize *= fontsizedecrease;
    }else{
      c++;
      if(c==11){
        fontsize *= 0.75;
      }
    }

    tint(255);
    image(drawing,0,0);


  if (keyCode == LEFT) {
    image(austria,0,0);
    }
   // if (keyCode == RIGHT) {
     // frog1.frogx = frog1.frogx + 1;
   // }


    if(mousePressed){
      tint(255,100);
      image(australia,0,0);
    }
  }else{
    tint(255);
    image(drawing,0,0);
    println(c+" "+letters.length());
    /*
    save("mlk-"+hour()+""+minute()+""+second()+".tif");
    exit();
    */
    noLoop();
  }
} 
boolean letterfit(){
  letter.beginDraw();
  letter.background(255,0);
  letter.fill(0);
  letter.textAlign(CENTER,CENTER);
  letter.translate(fontsize/2,fontsize/2);
  letter.rotate(random(TWO_PI));
  letter.scale(fontsize/fontstart);
  letter.textFont(font);
  letter.smooth();
  letter.text(letters.charAt(c),0,0);
  letter.endDraw();
  lettersquare.beginDraw();

@JoachimIsaksson yes, I don't call letter fit until later on — Christine Austin
– Christine Austin, Commented Nov 28, 2012 at 16:27
I would print out the value of letter at the beginning of letterfit(). It probably is 0. Somehow! — emrys57
– emrys57, Commented Nov 28, 2012 at 16:31
@ChristineAustin try to print the return value from your graphicwatever call — PermGenError
– PermGenError, Commented Nov 28, 2012 at 16:32
It's just peculiar how at one point I could take the whole code from the site I'm referencing and the code worked, but now if I try doing that, Im getting the Error.... — Christine Austin
– Christine Austin, Commented Nov 28, 2012 at 16:50

Joachim Isaksson · Accepted Answer · 2012-11-28 16:50:00Z

2

You've most likely been hit by issue 1217, which prevents you from using an OpenGL PGraphics renderer if the main renderer is Java2D.

The link has a workaround, which basically involves changing the main renderer to OpenGL.

A newer version of PGraphics should give you a more detailed exception.

answered Nov 28, 2012 at 16:50

Joachim Isaksson

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3 Comments

Christine Austin Over a year ago

Ah I can see now, is this all because of Processing 2.0b1? I'm just worried cause I'm using this for an assignment and the school computers run on a previous version where my original code works.

Joachim Isaksson Over a year ago

@ChristineAustin From what I know, it's related to 2.x versions only, 1.x should work.

Christine Austin Over a year ago

Alrighty, tysm for all your help! I think I am going to play it save and run it on the 1.x version instead since the code is working there. I would have never noticed this on my own! Genius :]

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