Hello everyone.  I am a newcomer to Processing and programming and I am working on my first visualization.  I have run into a bit of a quirk.  When I try to run the code in the sketch window nothing happens; the play arrow is on but nothing shows.  However, when I export the code as a firefox applet, I can open it up and it runs as expected with no problems. In my sketch, I worked out how to make 3 circles spin in a triangle formation.  Then I tried to convert the code into an object so that I could easily draw multiple groups with different variables.  I believe this is where I might have changed something around, because afterwards it stoped previewing.  This is my code:

Tri t1, t2, t3;

void setup () {
 size (200,400) ;
 stroke (255) ;
 fill (255) ;
 smooth () ;
 framerate (60) ;
 t1 = new Tri (width/2, 350, 10, 5, 0.25);
 t2 = new Tri (width/2, height/2, 10, 10, 0.3);
 t3 = new Tri (width/2, 50, 10, 15, 0.35);
}

void draw () {
 background (0);
 t1.update ();
 t2.update ();
 t3.update ();
 t1.display ();
 t2.display ();
 t3.display ();
 }

class Tri {
 float rOne; // ellipse radius
 float rTwo; // distance from center
 float theta;
 int xpos;
 int ypos;
 float rot;
 float rotSpeed;
 float diam = 0;
 float dSpeed;
 
 Tri (int x, int y, float r, float rtS, float dS) {
   xpos = x;
   ypos = y;
   rOne = r;
   rotSpeed = rtS;
   dSpeed = dS;
   }
   void update () {
   rTwo = rOne/(sqrt(3)/2); // set triangle radius based on circle size
 
   diam = diam + dSpeed;
   if (diam > rOne*2) {diam = rOne*2;}
   theta = radians(rot);
   rot = rot+rotSpeed%360;
   }
   
   void display () {
     ellipse (xpos+(cos(theta)*rTwo), ypos+(sin(theta)*rTwo),diam,diam);
     ellipse (xpos+(cos(theta+(TWO_PI/3))*rTwo), ypos+(sin(theta+(TWO_PI/3))*rTwo),diam,diam);
     ellipse (xpos+(cos(theta-(TWO_PI/3))*rTwo), ypos+(sin(theta-(TWO_PI/3))*rTwo),diam,diam);
   }
}
   

I'm excited to continue building upon this but I do not want to export the code everytime to test it out.  If anyone has any insight as to why this is happening I would greatly appreciate it!

what platform are you using? perhaps linux?

i don't know where to post this:
i have seen somewhere a while back a very nice processing sketch called "pipes" i believe, where the mouse displacement makes the image (of pipes) slowly appear.
does that ring a bell to someone?
i would like very much to find this sketch again, please tell me where it is!