A while back there was some traffic concerning the Background
node's image component---it doesn't rescale to fit a resized
canvas. Attached is some code that provides, as an example,
a rescalable background image.
GradientImage - creates a gradient BufferedImage using
Java 2D's gradient paint capabilities.
RescalableCanvas - a subclass of Canvas3D that catches resize
events and rescales an attached Background's
image to match.
HelloUniverse - a slightly hacked version of the standard
Java 3D demo that uses the above classes to
to provide a rescalable gradient background
image.
javac HelloUniverse.java
java HelloUniverse
Critical feedback (or otherwise) welcome.
--
Allen McPherson
[EMAIL PROTECTED]
// Copyright (c) 2000 by Allen Lynn McPherson. All rights reserved.
// This example is provided WITHOUT ANY WARRANTY either expressed or implied.
import java.awt.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
// Creates a gradient image using the Java 2D API. Generally used
// for view backgrounds.
public class GradientImage extends BufferedImage {
public GradientImage() {
this(128, 128);
}
public GradientImage(int width, int height) {
super(width, height, BufferedImage.TYPE_INT_RGB);
GradientPaint grad =
new GradientPaint(0, 0, new Color(0,0,128), 0, height, Color.white);
Graphics2D g2d = this.createGraphics();
g2d.setPaint(grad);
g2d.fillRect(0, 0, width, height);
}
}
// Copyright (c) 2000 by Allen Lynn McPherson. All rights reserved.
// This example is provided WITHOUT ANY WARRANTY either expressed or implied.
import java.awt.event.*;
import java.awt.*;
import java.awt.image.*;
import java.awt.geom.AffineTransform;
import javax.media.j3d.*;
import javax.vecmath.*;
// Subclass of Canvas3D (and hence Canvas) that catches resize events and
// rescales a Background's image.
// Associated Background must:
// - have been inserted into the scene graph
// - have good application bounds set
// - have its ALLOW_IMAGE_WRITE capability bit set
public class RescalableCanvas extends Canvas3D {
GradientImage gImage = null; // Original gradient image to rescale
Background bg = null; // Will have it's image set and reset
Dimension origDim = null; // Original canvas dimensions
boolean beenHere = false; // Used to ensure single image create
// No Background yet--must be set with setBG()
public RescalableCanvas(java.awt.GraphicsConfiguration gc) {
this(gc, null);
}
// Sets member Background and event listener (component resize)
public RescalableCanvas(java.awt.GraphicsConfiguration gc, Background bg) {
super(gc);
this.bg = bg;
addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent e) {
// First time through, create initial gradient image to match initial
// Canvas dimensions (if neither dimension is 0).
if (!beenHere) {
beenHere = createOriginalGradient();
return;
}
// Subsequent times through, just rescale the original image and
// reset the Background's image.
rescaleAndSet((double)(getSize().width) / (double)origDim.width,
(double)(getSize().height) / (double)origDim.height);
}
});
}
public void setBG(Background bg) {
this.bg = bg;
}
// Called to greate initial gradient image. Once this method returns true
// it will not be called again.
protected boolean createOriginalGradient() {
if (bg == null) return true;
origDim = getSize();
if (origDim.width==0 || origDim.height==0)
return false;
gImage = new GradientImage(origDim.width, origDim.height);
bg.setImage(new ImageComponent2D(ImageComponent.FORMAT_RGBA, gImage));
return true; // Don't call this method again.
}
// Rescales the initial gradient image to match the canvas' new size and
// applies it to Background node.
protected void rescaleAndSet(double xScale, double yScale) {
if (xScale == 1.0 && yScale == 1.0)
return;
if (bg == null) return;
AffineTransformOp op =
new AffineTransformOp(AffineTransform.getScaleInstance(xScale, yScale),
null);
BufferedImage bimg = op.filter(gImage, null);
bg.setImage(new ImageComponent2D(ImageComponent.FORMAT_RGBA, bimg));
return;
}
}
/*
* @(#)HelloUniverse.java 1.47 99/09/15 13:36:59
*
* Copyright (c) 1996-1999 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.
*/
import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.event.*;
import java.awt.GraphicsConfiguration;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.geometry.ColorCube;
import com.sun.j3d.utils.universe.*;
import javax.media.j3d.*;
import javax.vecmath.*;
public class HelloUniverse extends Applet {
// Changed to accept a RescalableCanvas
public BranchGroup createSceneGraph(RescalableCanvas canvas) {
// 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 simple shape leaf node, add it to the scene graph.
objTrans.addChild(new ColorCube(0.4));
// Create a new Behavior object that will perform the desired
// operation on the specified transform object and add it into
// the scene graph.
Transform3D yAxis = new Transform3D();
Alpha rotationAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE,
0, 0,
4000, 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);
// Changed to add Background node with image that will be
// rescaled when the canvas is resized.
Background bg = new Background();
bg.setCapability(Background.ALLOW_IMAGE_WRITE);
bg.setApplicationBounds(new BoundingSphere(new Point3d(0,0,0), 100));
canvas.setBG(bg);
objRoot.addChild(bg);
// Have Java 3D perform optimizations on this scene graph.
objRoot.compile();
return objRoot;
}
public HelloUniverse() {
setLayout(new BorderLayout());
GraphicsConfiguration config =
SimpleUniverse.getPreferredConfiguration();
RescalableCanvas c = new RescalableCanvas(config);
add("Center", c);
// Create a simple scene and attach it to the virtual universe
BranchGroup scene = createSceneGraph(c);
SimpleUniverse u = new SimpleUniverse(c);
// This will move the ViewPlatform back a bit so the
// objects in the scene can be viewed.
u.getViewingPlatform().setNominalViewingTransform();
u.addBranchGraph(scene);
}
//
// The following allows HelloUniverse to be run as an application
// as well as an applet
//
public static void main(String[] args) {
new MainFrame(new HelloUniverse(), 256, 256);
}
}
