Re: [JAVA3D] How to set Geometry of a shape3d at runtime.

[Myron Smith]

You can detach the node if you set up the properties to allow you to do so
ahead of time, here is a small example program that does these things:

import java.applet.Applet;
import java.awt.event.*;
import javax.vecmath.*;
import javax.media.j3d.*;
import java.awt.*;

import com.sun.j3d.utils.universe.SimpleUniverse;
import com.sun.j3d.utils.universe.ViewingPlatform;
import com.sun.j3d.utils.applet.MainFrame;

import com.sun.j3d.utils.geometry.*;
import java.util.Enumeration;

public class TestBed2 extends Applet implements ActionListener
{
  TimerBehavior myBehavior = new TimerBehavior();
  Behavior rotation = null;
  BranchGroup timeBranch, mainBranch;

  static public void main(String[] args)
  {
        new MainFrame(new TestBed2(), 300, 300);
  }

  TestBed2()
  {
    setLayout(new BorderLayout());

    // Make the canvas.  Use our derived canvas to compute frame rate.
    GraphicsConfigTemplate3D template = new GraphicsConfigTemplate3D();
    GraphicsConfiguration gcfg =
              GraphicsEnvironment.getLocalGraphicsEnvironment().
              getDefaultScreenDevice().getBestConfiguration(template);
    Canvas3D canvas = new Canvas3D(gcfg);
    canvas.setSize(300, 300);
    add("Center", canvas);

    // Make a button to toggle the behaviors.
    Button button = new Button("PressMe");
        add("East", button);
        button.addActionListener(this);

    // Create the universe.
    SimpleUniverse universe = new SimpleUniverse(canvas);

    // Create the main branch... add a rotating square for fun.
    mainBranch = new BranchGroup();
    mainBranch.setCapability(BranchGroup.ALLOW_CHILDREN_EXTEND);
    mainBranch.setCapability(BranchGroup.ALLOW_CHILDREN_WRITE);
    RotatingSquare square = new RotatingSquare(0.0f, 0.0f);
    mainBranch.addChild(square);

    // Point to the rotation behavior so we can toggle it.
    rotation = square.rotint;

    // Add the timer behavior that will also be toggled.
    timeBranch = new BranchGroup();
    timeBranch.setCapability(BranchGroup.ALLOW_DETACH);
    myBehavior.setSchedulingBounds(
          new BoundingSphere(new Point3d(0.0, 0.0, 0.0), 1000.0));
    timeBranch.addChild(myBehavior);

    mainBranch.addChild(timeBranch);

    // Make the main branch live.
    universe.addBranchGraph(mainBranch);
  }

  public void actionPerformed(ActionEvent event)
  {
    String command = event.getActionCommand();
    if (command.equals("PressMe"))
    {
      boolean enabled = myBehavior.getEnable();
      if (enabled) //myBehavior.setEnable();
        timeBranch.detach();
      else
        mainBranch.addChild(timeBranch);

      myBehavior.setEnable(!enabled);
      rotation.setEnable(!rotation.getEnable());
    }

  }

} // END class TestBed2




class TimerBehavior extends Behavior
{
  WakeupOnElapsedTime myWakeup = null;
  int counter = 0;

  public TimerBehavior()
  {
  }

  public void initialize()
  {
        myWakeup = new WakeupOnElapsedTime(1000);
    wakeupOn (myWakeup);
  }

  public void setEnable(boolean state)
  {
        super.setEnable(state);
        System.out.println("state: " + state);
  }

  public void processStimulus(Enumeration criteria)
  {
    WakeupCriterion wakeup = null;
    while(criteria.hasMoreElements())
    {
      wakeup = (WakeupCriterion)criteria.nextElement();
      if (wakeup instanceof WakeupOnElapsedTime)
      {
                counter++;
                System.out.println("I'm awake!  " + counter);
      }

    } // END while

    wakeupOn (myWakeup);
  } // END processStimulus()

}


class RotatingSquare extends BranchGroup
{
  public RotationInterpolator rotint = null;

  RotatingSquare(float cx, float cy)
  {
  TransformGroup rotateGroup = new TransformGroup();
  rotateGroup.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
  Transform3D local = new Transform3D();
  local.rotX(1.57); // this will move the axis of rotation from +Y to +Z
axis
  local.setTranslation(new Vector3f(cx, cy, 0.0f));
  Alpha alpha = new Alpha(-1, 6000);
  rotint =
    new RotationInterpolator(alpha, rotateGroup,
                             local, 0.0f, 6.28f);
  rotint.setSchedulingBounds(
    new BoundingSphere(new Point3d(0.0, 0.0, 0.0), 1000.0));

  Point3f[] coords = new Point3f[]
  {
    new Point3f(cx+-0.5f, cy+-0.5f, -20.0f),
    new Point3f(cx+ 0.5f, cy+-0.5f, -20.0f),
    new Point3f(cx+-0.5f, cy+ 0.5f, -20.0f),
    new Point3f(cx+ 0.5f, cy+ 0.5f, -20.0f)
  };
  int[] stripVertexCounts = new int[1];
  stripVertexCounts[0] = 4;
  TriangleStripArray groundGeom =
    new TriangleStripArray(4, GeometryArray.COORDINATES, stripVertexCounts);
  groundGeom.setCoordinates(0, coords);
  Appearance appearance = new Appearance();

  Shape3D ground = new Shape3D(groundGeom, appearance);
  rotateGroup.addChild(ground);

  this.addChild(rotateGroup);
  this.addChild(rotint);

  }
}

-----Original Message-----
>From: Mohammed Akacem [mailto:[EMAIL PROTECTED]]
>Sent: Tuesday, May 30, 2000 7:14 AM
>To: [EMAIL PROTECTED]
>Subject: [JAVA3D] How to set Geometry of a shape3d at runtime.
>
>
>I am viewing a Shape3D object in an applet. I want to remove the shape3d
>
>object at runtime when I click  a close button so I can later set the
>geoemtry of my shape3D object again to show another visuel object. How
>should I proceed.
>
>Thanks a lot
>
>Mohammed

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