> From: Brandon Kohn <[EMAIL PROTECTED]>
>
> I'm attempting to change the opacity of an array of points (pointarray)
> based on the value of a JSlider (swing component). I'm looking into the use
> of behaviors, but they seem to support only AWT component events.
Here is an example of using Behavior.postId() to make a change to the scene
graph. The attribute being changed is the polygon offset, but otherwise this is
just what you are looking for.
To review:
-- If you are making a single change to the scene graph, you can just
make your change from your UI event handling code.
-- If you are making several changes, then you may want to use
Behavior.postId() to group your changes into a single frame.
This example makes a single change, but it shows the general concept.
Doug Gehringer
Sun Microsystems
========== CUT HERE and save to PolygonOffsetPostId.java =============
/*
*
* Copyright (c) 1996-1998 Sun Microsystems, Inc. All Rights Reserved.
*
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
*/
/**
* This example shows how to make syncronized scene graph changes using
* Behavior.postId(). See the usage of UpdateBehavior
*/
import javax.swing.*;
import javax.swing.event.*;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.*;
import java.awt.GraphicsConfiguration;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.geometry.Sphere;
import com.sun.j3d.utils.universe.*;
import javax.media.j3d.*;
import javax.vecmath.*;
import java.util.Enumeration;
public class PolygonOffsetPostId extends JFrame implements ChangeListener {
JLabel sliderValueLabel;
PolygonAttributes solidPa;
UpdateBehavior updateBehavior;
float pendingOffset;
public BranchGroup createSceneGraph() {
// Create the root of the branch graph
BranchGroup objRoot = new BranchGroup();
// Create the transform group node and initialize it to the
// identity. Enable the TRANSFORM_WRITE capability so that
// our behavior code can modify it at runtime. Add it to the
// root of the subgraph.
TransformGroup objTrans = new TransformGroup();
objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
objRoot.addChild(objTrans);
// Create a Sphere. We will display this as both wireframe and
// solid to make a hidden line display
// wireframe
Appearance wire = new Appearance();
PolygonAttributes wirePa = new PolygonAttributes(
PolygonAttributes.POLYGON_LINE,
PolygonAttributes.CULL_BACK,
0.0f);
wire.setPolygonAttributes(wirePa);
Sphere wireSphere = new Sphere(0.7f, wire);
objTrans.addChild(wireSphere);
// solid
Color3f red = new Color3f(1.0f, 0.0f, 0.0f);
ColoringAttributes solidCa = new ColoringAttributes(red,
ColoringAttributes.SHADE_FLAT);
Material solidMat = new Material();
solidMat.setLightingEnable(false);
Appearance solid = new Appearance();
solid.setMaterial(solidMat);
solid.setColoringAttributes(solidCa);
solidPa = new PolygonAttributes(
PolygonAttributes.POLYGON_FILL,
PolygonAttributes.CULL_BACK,
0.0f);
solidPa.setCapability(PolygonAttributes.ALLOW_OFFSET_WRITE);
solid.setPolygonAttributes(solidPa);
Sphere solidSphere = new Sphere(0.7f, solid);
objTrans.addChild(solidSphere);
// Create a new Behavior object that will perform the desired
// operation on the specified transform object and add it into
// the scene graph.
AxisAngle4f axisAngle = new AxisAngle4f(0.0f, 0.0f, 1.0f,
-(float)Math.PI / 2.0f);
Transform3D yAxis = new Transform3D();
Alpha rotationAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE,
0, 0,
80000, 0, 0,
0, 0, 0);
RotationInterpolator rotator =
new RotationInterpolator(rotationAlpha, objTrans, yAxis,
0.0f, (float) Math.PI*2.0f);
BoundingSphere bounds =
new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);
rotator.setSchedulingBounds(bounds);
objTrans.addChild(rotator);
// Create an UpdateBehavior to handle external scene graph changes
updateBehavior = new UpdateBehavior(this);
// set scheduling bounds
updateBehavior.setSchedulingBounds(bounds);
// make sure to add the updateBehavior to the scene graph
objTrans.addChild(updateBehavior);
// Have Java 3D perform optimizations on this scene graph.
objRoot.compile();
return objRoot;
}
// store the pending change and post the event.
public void stateChanged(ChangeEvent e) {
JSlider source = (JSlider)e.getSource();
pendingOffset = source.getValue();
updateBehavior.postId(UpdateBehavior.POFFSET_CHANGE);
}
public void updatePolygonOffset() {
// update the scene graph
solidPa.setPolygonOffset(pendingOffset);
// update the UI
sliderValueLabel.setText(Float.toString(pendingOffset));
}
// this class could also be in a separate .java file, included here
// to make it easy to download
/**
* This behavior allows scene graph changes caused by external events
* (such as a UI event) to change the scene graph from a behavior, which
* ensures that all the scene graph edits will show up on the same frame
*
* The scene graph changes are made by the "owner" of the behavior. When
* the UI change happens, the owner saves the pending change calls
* Behavior.postId() with an ID specifying the pending change, and then
* the behavior wakes up and calls the method corresponding to the ID.
*
*/
public class UpdateBehavior extends Behavior {
PolygonOffsetPostId owner; // who to notify
// Define more post id's as necessary.
public static final int POFFSET_CHANGE = 1;
// Add a criteria for each post id
WakeupCriterion criterion[] = {
new WakeupOnBehaviorPost(null, POFFSET_CHANGE)
};
WakeupCondition conditions = new WakeupOr( criterion );
public UpdateBehavior(PolygonOffsetPostId owner) {
super();
this.owner = owner;
}
public void initialize() {
wakeupOn(conditions);
}
public void processStimulus( Enumeration criteria) {
while (criteria.hasMoreElements()) {
WakeupOnBehaviorPost post =
(WakeupOnBehaviorPost)criteria.nextElement();
switch (post.getPostId()) {
case POFFSET_CHANGE:
owner.updatePolygonOffset();
break;
default:
System.out.println("Unknown post id: " +
post.getPostId());
break;
}
}
wakeupOn(conditions);
}
}
public PolygonOffsetPostId() {
super("Polygon Offset PostId");
JPanel contentPane = new JPanel();
contentPane.setLayout(new BorderLayout());
GraphicsConfiguration config =
SimpleUniverse.getPreferredConfiguration();
Canvas3D canvas = new Canvas3D(config);
canvas.setSize(800, 800);
contentPane.add(canvas, BorderLayout.CENTER);
setContentPane(contentPane);
// Create a simple scene and attach it to the virtual universe
BranchGroup scene = createSceneGraph();
SimpleUniverse u = new SimpleUniverse(canvas);
// This will move the ViewPlatform back a bit so the
// objects in the scene can be viewed.
u.getViewingPlatform().setNominalViewingTransform();
u.addBranchGraph(scene);
JPanel sliderPanel = new JPanel();
JLabel sliderLabel = new JLabel("Polygon Offset");
sliderPanel.add(sliderLabel);
JSlider offsetSlider = new JSlider(JSlider.HORIZONTAL, 0, 1500, 0);
offsetSlider.addChangeListener(this);
sliderPanel.add(offsetSlider);
sliderValueLabel = new JLabel("0.0");
sliderPanel.add(sliderValueLabel);
contentPane.add(sliderPanel, BorderLayout.SOUTH);
pack();
show();
}
//
// The following allows PolygonOffsetPostId to be run as an application
// as well as an applet
//
public static void main(String[] args) {
new PolygonOffsetPostId();
}
}
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