[JAVA3D] Transparent Objects

Greg Hopkins Wed, 05 Jul 2000 17:34:20 -0700

Hi,

Like Falk Doberman I am having some problems using transparency.

My program attempts to display a spinning ball in transparent red and green. I was hoping that I would be able to see a nice 3D ball with my red/green specs.

Instead I get a mostly green ball with a red shadow and some cool-looking but unintended disc-shaped shadows appearing and disappearing within it. I don't understand why.

Could anyone be kind enough to point out where I'm going wrong?

Greg.

import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.*;
import java.awt.event.*;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.universe.*;
import com.sun.j3d.utils.image.TextureLoader;
import javax.media.j3d.*;
import javax.vecmath.*;
import com.sun.j3d.utils.geometry.Sphere;
import com.sun.j3d.utils.behaviors.keyboard.KeyNavigatorBehavior;

public class Ball extends Applet {
TransformGroup vpTrans = null;

    private BranchGroup createSceneGraph() {
     // Create the root of the branch graph
     BranchGroup objRoot = new BranchGroup();
       // Create a bounds for the background and lights
BoundingSphere bounds =
     new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);

// Set up the global lights
Color3f lColor1 = new Color3f(0.7f, 0.7f, 0.7f);
Vector3f lDir1 = new Vector3f(-1.0f, -1.0f, -1.0f);
Color3f alColor = new Color3f(0.2f, 0.2f, 0.2f);

AmbientLight aLgt = new AmbientLight(alColor);
aLgt.setInfluencingBounds(bounds);
DirectionalLight lgt1 = new DirectionalLight(lColor1, lDir1);
lgt1.setInfluencingBounds(bounds);
objRoot.addChild(aLgt);
objRoot.addChild(lgt1);

     // Create objects with a behavior and add them
     // into the scene graph.
TransformGroup spinTg = new TransformGroup();
     spinTg.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
Transform3D yAxis = new Transform3D();
Alpha rotationAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE,
     0, 0,
     5000, 0, 0,
     0, 0, 0);
     Alpha rotationAlpha2 = new Alpha(-1, Alpha.INCREASING_ENABLE,
     0, 0,
     5000, 0, 0,
     0, 0, 0);

RotationInterpolator rotator =
new RotationInterpolator(rotationAlpha, spinTg, yAxis,
0.0f, (float) Math.PI*2.0f);

BoundingSphere bounds2 =
new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);

rotator.setSchedulingBounds(bounds);
//
TransformGroup spinTg2 = new TransformGroup();
spinTg2.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);

RotationInterpolator rotator2 =
new RotationInterpolator(rotationAlpha2, spinTg2, yAxis,
0.0f, (float) Math.PI*2.0f);

rotator2.setSchedulingBounds(bounds2);

Appearance appearance = createAppearance();
Sphere sphere = new Sphere(0.5f, appearance);

Appearance greenAppearance = createAppearance2();
     Sphere greenSphere = new Sphere(0.5f, greenAppearance);
        Transform3D t = new Transform3D();
      t.set(1, new Vector3d(-0.07, 0.0, 0.0));
TransformGroup objTrans = new TransformGroup(t);
     objTrans.addChild(rotator);
objTrans.addChild(spinTg);
spinTg.addChild(greenSphere);

TransformGroup objTrans2 = new TransformGroup();
objTrans2.addChild(rotator2);
objTrans2.addChild(spinTg2);
spinTg2.addChild(sphere);
objRoot.addChild(objTrans);
objRoot.addChild(objTrans2);

//objRoot.addChild(sphere);

     return objRoot;
    }
    private Appearance createAppearance() {
     Appearance app = new Appearance();

// Set up the transparency properties
TransparencyAttributes ta = new TransparencyAttributes();
ta.setTransparencyMode(ta.BLENDED);
ta.setTransparency(0.6f);
app.setTransparencyAttributes(ta);

// Set up the polygon attributes
PolygonAttributes pa = new PolygonAttributes();
pa.setCullFace(pa.CULL_NONE);
app.setPolygonAttributes(pa);

// Set up the material properties
Color3f black = new Color3f(0.0f, 0.0f, 0.0f);
Color3f objColor = new Color3f(1.0f, 0.0f, 0.0f);
app.setMaterial(new Material(objColor, black, objColor,
black, 1.0f));

return app;
    }
    private Appearance createAppearance2() {
    Appearance app = new Appearance();

// Set up the transparency properties
TransparencyAttributes ta = new TransparencyAttributes();
ta.setTransparencyMode(ta.BLENDED);
ta.setTransparency(0.6f);
app.setTransparencyAttributes(ta);

// Set up the polygon attributes
PolygonAttributes pa = new PolygonAttributes();
pa.setCullFace(pa.CULL_NONE);
app.setPolygonAttributes(pa);

// Set up the material properties
Color3f black = new Color3f(0.0f, 0.0f, 0.0f);
Color3f objColor = new Color3f(0.0f, 1.0f, 0.0f);
app.setMaterial(new Material(objColor, black, objColor,
black, 1.0f));

return app;
}

    public Ball() {
setLayout(new BorderLayout());
        GraphicsConfiguration config =
           SimpleUniverse.getPreferredConfiguration();

Canvas3D c = new Canvas3D(config);
add("Center", c);

// Create a simple scene and attach it to the virtual universe
BranchGroup scene = createSceneGraph();
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();
vpTrans = u.getViewingPlatform().getViewPlatformTransform();
KeyNavigatorBehavior keyNavBeh = new KeyNavigatorBehavior(vpTrans);
keyNavBeh.setSchedulingBounds(new BoundingSphere(
   new Point3d(),1000.0));
scene.addChild(keyNavBeh);

u.addBranchGraph(scene);
}

    //
    // The following allows Ball to be run as an application
    // as well as an applet
    //
    public static void main(String[] args) {
new MainFrame(new Ball(), 700, 700);
}
}

[JAVA3D] Transparent Objects

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