3D Viewer: Universes synchronization

Posted by Juanjo Vega on Jun 11, 2010; 9:54am
URL: http://imagej.273.s1.nabble.com/3D-Viewer-Universes-synchronization-tp3687928.html

Hi,

After I got 3D viewer sources, I have spent some time debugging my
plugin. It hangs when I forward events between two universes, and so far
I found the point where it hangs.

To get you in context:

The main class implements "UniverseListener" interface (thanks Johannes
for pointing this out), which has three methods that I implement in the
following way:

    public void transformationStarted(View view) {
    }

    public void transformationUpdated(View view) {
        synchronizeUniverses(view);
    }

    public void transformationFinished(View view) {
        synchronizeUniverses(view);
    }

I register the listener for both universes:

Image3DUniverse universe.addUniverseListener(this);

So, whenever a transformation is made in one of them, the
"synchronizeUniverses" method will be invoked:


private void synchronizeUniverses(View view) {
        if (!dispatched) {
            dispatched = true;  // Avoids infinite events forwarding

            if (view == universeVolume.getCanvas().getView()) {
                universeVolume.getGlobalTransform(gt);
                universeSphere.setGlobalTransform(gt);
            } else {
                universeSphere.getGlobalTransform(gt);
                universeVolume.setGlobalTransform(gt);
            }

            dispatched = false; // Reactivate events.
        }
    }

Notice that the "dispatched" variable should avoid infinite events
forwarding. Unluckily it doesn't work.

There are two universes, so when events come from "universeVolume", it
gets it's global transform to sets it at "universeSphere" and vice
versa.

When I drag one of the universes, it locks, but if I remove the
"transformationUpdated", so only the transform will be updated when
mouse is released, it works.

Debugging inside 3D_Viewer sources I found that it hangs at
"frameBehavior.wait()", where it stays locked forever.

    public void waitForNextFrame() {
        if (win == null) {
            return;
        }
        frameBehavior.postId(WaitForNextFrameBehavior.TRIGGER_ID);
        synchronized (frameBehavior) {
            try {
                frameBehavior.wait();
            } catch (Exception e) {
            }
        }
    }

I think it's a problem related to the "synchronized" part, because I
tried to set the wait for 1 second and then infinite event forwarding
appeared, but I can't manage how to fix that.

Any help will be welcome, as this is the only remaining issue to finish
my plugin :)

Sincerelly,

Juanjo Vega.