DisplayList.pde

class DisplayList {
    List objects = new LinkedList();

    public void add(DisplayObject o) {
        objects.add(o);
    }
    
    public void update() {
        ListIterator it = objects.listIterator();
        
        while (it.hasNext()) {
            DisplayObject fo = (DisplayObject)it.next();
            fo.update(it);
        }
    }
    
    public void hitTest() {
        // Compare all pairs
        ListIterator lit = objects.listIterator(0);
        ArrayList newObjects = new ArrayList();
        FlyingObject l, r = null;
        Object x;
        
        if (!noHit) {
            while (lit.hasNext()) {
                x = lit.next(); 
                if (!(x instanceof FlyingObject)) continue;
                
                l = (FlyingObject)x;
                if (l.remove) continue;
                
                ListIterator rit = objects.listIterator(lit.nextIndex());
    
                while (rit.hasNext()) {
                    x = rit.next(); 
                    if (!(x instanceof FlyingObject)) continue;
    
                    r = (FlyingObject)x;
                    if (r.remove) continue;
                    
                    if (l.intersects(r)) {
                        l.collide(r, newObjects);
                        r.collide(l, newObjects);
                        break;
                    }
                }
            }
        }
        
        // Remove dead objects.
        Iterator it = objects.iterator();
        
        while (it.hasNext()) {
            DisplayObject fo = (DisplayObject)it.next();
            
            if (fo.remove) {
                println("yanking " + fo.getClass().getName());
                it.remove();
            }
        }
        
        // Add new objects.
        it = newObjects.iterator();
        
        while (it.hasNext())
            objects.add(it.next());
    }
    
    public Iterator iterator() {
        return objects.iterator();
    }
}