I like the P3D renderer because it is much faster than the default renderer (which is very slow using the video lib).

But there is a strange behaviour in it. - It draws incorrectly and this can be seen in the following example where the rects around the mouse are drawn in incorrenct sizes when the mouse is moved.

I am on OS X 10.3.8, in case you don't get the same behaviour:

code :

----

Form aform;

void setup() {
 size(400,400, P3D);  // DELETE P3D and it works fine !!!
 aform = new Form(20, 200);
}

void draw() {
 background(122);
 aform.update();
}

class Form {
 int x;
 int y;

 Form(int _x, int _y) {
   x = _x;
   y = _y;
 }

 void update(){
   x = mouseX - 20;
   y = mouseY - 20;
   rect(x-10, y - 5, 4, 10);
   rect(x, y+10, 4, 12);
   rect(x+5, y-10, 12, 4);  
 }
}

now filed in the bugs db, closing thread:
http://dev.processing.org/bugs/show_bug.cgi?id=95