title: Case expressions must be constant expression
body: <p>Having some issues with the processing language where it says the case expressions must be constants, but I could have sworn they were. I don't know what I am doing wrong here. Anyone have some tips?</p>
  
  <pre><code>int gameState;
  static int MENU = 0;
  static int GAME = 1;
  static int OPTIONS = 2;
  
  void setup() {
    screenSizex = 960;
    screenSizey = 640;
    size(screenSizex, screenSizey);
    gameState = MENU;
  }
  
  void draw(){
    switch(gameState) {
      case MENU:
        //does menu stuff
        break;
      case OPTIONS:
        //does options stuff
        break;
      case GAME:
        //does game stuff
        break;
      default:
        break;
    }
  }
  
  void mousePressed() {
    if (//over some object) {
      gameState = GAME;
    }
    else if (//over some object) {
      gameState = OPTIONS;
    }
    else if (//over some object) {
      exit();
    }
  }
  </code></pre>