>
> I've posted this question before, and have seen it asked by others, but I've
> never seen an answer:
>
> If I've got a QuadArray (and I assume TriangleArray as well) with
> per-vertex-colors, how do I set up the Material so I get shading with the
> colors I've put in?
>
> Seems a simple question, but I get the feeling it can't be done which would
> be a huge drawback to Java3d.
>
Attached is an example program I did by changing HelloUniverse.
It is simply a single quad with colors at it's vertices and one directional
light.
Dan Petersen
Java 3D Team
Sun Microsystems
** Look for the new newsgroup: comp.lang.java.3d **
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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 {
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);
int stripCount[] = new int[1];
stripCount[0] = 4;
QuadArray qa = new QuadArray(4,
QuadArray.COORDINATES |
QuadArray.COLOR_3 |
QuadArray.NORMALS
);
float coords[] = { -0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.5f, 0.5f, 0.0f,
-0.5f, 0.5f, 0.0f };
float colors[] = { 1.0f, 0.0f, 1.0f,
1.0f, 0.0f, 0.0f,
0.0f, 1.0f, 0.0f,
0.0f, 0.0f, 1.0f };
float norms[] = { 0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f };
qa.setCoordinates(0, coords);
qa.setColors(0, colors);
qa.setNormals(0, norms);
Appearance ap = new Appearance();
PolygonAttributes pa = new PolygonAttributes();
pa.setCullFace(pa.CULL_NONE);
ap.setPolygonAttributes(pa);
Material mat = new Material();
ap.setMaterial(mat);
Shape3D s3d = new Shape3D(qa, ap);
// Create a simple shape leaf node, add it to the scene graph.
objTrans.addChild(s3d);
BoundingSphere bounds =
new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);
DirectionalLight dl = new DirectionalLight();
dl.setInfluencingBounds(bounds);
objTrans.addChild(dl);
// 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);
rotator.setSchedulingBounds(bounds);
objTrans.addChild(rotator);
// Have Java 3D perform optimizations on this scene graph.
objRoot.compile();
return objRoot;
}
public HelloUniverse() {
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();
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);
}
}
