import java.awt.BorderLayout;
import java.awt.Frame;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.media.j3d.Appearance;
import javax.media.j3d.BranchGroup;
import javax.media.j3d.Canvas3D;
import javax.media.j3d.GeometryArray;
import javax.media.j3d.PolygonAttributes;
import javax.media.j3d.Shape3D;
import javax.media.j3d.TriangleArray;
import javax.vecmath.Point3f;
import javax.vecmath.Vector3f;

import com.sun.j3d.utils.universe.SimpleUniverse;

@SuppressWarnings("serial")
public class CullingTest extends Frame
{
	// #############################
	// # modify these to see bug:
	// #############################
	private final boolean ENABLE_BACKFACE_CULLING = true;
	private final boolean NORMAL_VECTOR_POINTS_IN_POSITIVE_Z = false;
	// #############################
	
	public class MyTriangleShape extends Shape3D
	{
		public MyTriangleShape()
		{
		    TriangleArray triaArray = new TriangleArray(3, GeometryArray.COORDINATES | GeometryArray.NORMALS);
		    Point3f[] vertices = new Point3f[3];
		    vertices[0] = new Point3f(0, 0, 0);
		    vertices[1] = new Point3f(1, 0, 0);
		    vertices[2] = new Point3f(0, 1, 0);
            triaArray.setCoordinates(0,vertices);
            
        	Vector3f normal = new Vector3f(0, 0, (NORMAL_VECTOR_POINTS_IN_POSITIVE_Z ? 1 : -1));
            System.out.println("Normal is: "+normal);
            System.out.println("Backface culling is: "+ENABLE_BACKFACE_CULLING);
            triaArray.setNormal(0, normal);
            triaArray.setNormal(1, normal);
            triaArray.setNormal(2, normal);
            
            this.setGeometry(triaArray);
		}
	}
	
	public CullingTest()
	{
		super("Culling Test");
		setLayout(new BorderLayout());
		setSize(600, 600);
		addWindowListener(new WindowAdapter() {
			@Override
			public void windowClosing(WindowEvent e)
			{
				dispose();
				System.exit(0);
			}
		});
		////////////////////////////////////
		Canvas3D canvas3D = new Canvas3D(SimpleUniverse.getPreferredConfiguration(), false);
		add(canvas3D, BorderLayout.CENTER);
		BranchGroup scene = new BranchGroup();
		Shape3D triangle = new MyTriangleShape();
		
	    Appearance l_Appearance = new Appearance();
	    PolygonAttributes l_PolyAttrib = new PolygonAttributes();
	    l_PolyAttrib.setPolygonMode(PolygonAttributes.POLYGON_FILL);
	    l_PolyAttrib.setCullFace(ENABLE_BACKFACE_CULLING ? PolygonAttributes.CULL_BACK : PolygonAttributes.CULL_NONE);
	    l_Appearance.setPolygonAttributes(l_PolyAttrib);
	    triangle.setAppearance(l_Appearance);

	    scene.addChild(triangle);

		SimpleUniverse uni = new SimpleUniverse(canvas3D);
		uni.getViewingPlatform().setNominalViewingTransform();

		uni.addBranchGraph(scene);
		////////////////////////////////////
	}

	public static void main(String[] args)
	{
		System.setProperty("sun.awt.noerasebackground", "true"); // needed due to an AWT repaint bug
		System.out.println("############");
		System.out.println("CullingTest");
		System.out.println("############");
		CullingTest test = new CullingTest();
		test.setVisible(true);
		System.out.println("\n############");
	}

}