// NavigateDyn.java:   Applet that shows how to retrieve viewpoints
//
// Daniel.Schneider@tecfa.unige.ch   1/98
// Freeware if you give a line of credit :)
//
// Changes in relation to Navigate.java in this directory
//   We query the Viewpoints Group for its viewpoints
//   We use arrays to store things
//   inspired by: http://www.tomco.net/~raf/faqs/TestExternal4.html
//                (TestExternal4 applet by Ross A. Finlayson 1997)

// Things have changed since the Late Nite Book !
//    See the initScene method
//    node.getExposedField("children") -> ....
//    MFNode -> EventOutMFNode

import java.awt.*;
import java.applet.*;
import java.awt.event.*;
import vrml.external.field.*;
import vrml.external.Node;
import vrml.external.Browser;
import vrml.external.exception.*;


public class NavigateDyn extends Applet {

    // The Browser
    Browser browser = null;
  
    // Various stuff in the VRML scene we hang on to

    // array for the various View Points found
    Node[] VPList ;
    // array for the handles to the set_bind EventIn Fields
    EventInSFBool[] set_VPList ;
    // array with the buttons generated
    Button[] VPButtons ;
    // The number of Viewpoints found in the scene
    int nVPs = 0;
  
    // "Aborted" state (used to disable some UI or code
    // if we've already had a fatal error)
    boolean aborted = false;
  
    /** Initialize the Applet */
    public void init() {
    
	// Connect to the browser
	browser = Browser.getBrowser (this);
	// Misc other UI setup
	Color c = Color.white;
	System.out.println("Setting bg color to: " + c);
	setBackground(c);
	System.out.println("NavigateDyn.init() done.");
    }
    
    /** Start the applet running */
    public void start(){
	System.out.println("Navigate Applet: start()...");
	// Initialize some VRML stuff and paint buttons
	initScene();
    }
    
    /** Stop the applet */
    public void stop(){
	System.out.println("Navigate Applet: stop()...");
    }
  
    /** This applet is about to be unloaded.  Do final cleanup. */
    public void destroy() {
	System.out.println("Navigate Applet: destroy()...");
    }	
  
  
    /** Handle a fatal error condition */
    public void die(String s) {
	System.out.println("Navigate Applet: FATAL ERROR!");
	System.out.println("--> " + s);
	System.out.println("Navigate Applet: Aborting...\n");
    
	aborted = true;   // Causes update() to display a warning
    }

 
    /** Set up some stuff in the VRML scene */
    public void initScene() {
	System.out.println("initScene()...");
	int i;
	// Get the ViewPoints
	try {
	    // Get the Group node called Viewpoints
	    Node Viewpoints = browser.getNode("Viewpoints");

	    // Extract the list of children
	    VPList = ((EventOutMFNode) (Viewpoints.getEventOut("children_changed"))).getValue();

	    // Initalize arrays for storing handles and Button strings
	    nVPs = VPList.length;
	    set_VPList = new EventInSFBool[nVPs];
	    VPButtons = new Button[nVPs];

	    for (i=0; i < nVPs ; i++) {

		// Get the handles for the Viewpoints set_bind Event fields

		System.out.println
		    ("initScene: node '" + VPList[i] + "')...");
		set_VPList[i] = (EventInSFBool)VPList[i].getEventIn("set_bind");
		System.out.println
		    ("initScene: got the EventIn: " + set_VPList[i]);

		// Insert push buttons into the Java applet

		String buttonLabel = "VP-" + i;
		add (VPButtons[i] = new Button(buttonLabel));
		System.out.println
		    ("initScene: Generated Button + string: " + VPButtons[i]);
	    }
	}
	catch(InvalidNodeException e){
	    System.out.println("InvalidNodeException: " + e);
	    die("initScene: VP node not found!");
	    return;
	}
	// or should I move this into the inner loop ?
	catch(InvalidEventInException e) {
	    die("bindToViewpoint: InvalidEventInException: " + e);
	    return;
	}
	catch(Exception e) {
	    die("Strange exception: " + e);
	    return;
	}
    }

    /** Handle actions from AWT widgets */
    public void actionPerformed (ActionEvent event) {
	Object button = event.getSource();
	for (int i=0; i < nVPs ; i++) {
	    if (button == VPButtons[i]) {
		// get the corresponding VP
		EventInSFBool set_bindVP = set_VPList[i];
		set_bindVP.setValue(true);
		System.out.println("action(): set_bound " + set_bindVP);
	    }
	}
    }
}