Java 画一个八面体

所以我试着画一个八面体，我喜欢90%的效果，但是物体的一部分没有正确着色。我认为在int坐标中的问题，我尝试了各种数字，但部分仍然被切断

import javax.vecmath.*; 

import javax.media.j3d.*;

public class Octahedron extends IndexedTriangleArray {
    public Octahedron(){
        super(8, TriangleArray.COORDINATES | TriangleArray.NORMALS, 24);
        setCoordinate(0, new Point3f(0f, 0f, 1f));
        setCoordinate(1, new Point3f(-1f, 0f, 0f));
        setCoordinate(2, new Point3f(0f, -1f, 0f));
        setCoordinate(3, new Point3f(1f, 0f, 0f));
        setCoordinate(4, new Point3f(0f, 1f, 0f));
        setCoordinate(5, new Point3f(0f, 0f, -1f));
        int[] coords = {3,0,5,0,2,5,2,0,4,0,3,4,5,1,3,2,1,5,4,1,2,3,1,4};
        float n = (float)(1.0/Math.sqrt(3));
        setNormal(0, new Vector3f(-n, -n, n));
        setNormal(1, new Vector3f(n, -n, n));
        setNormal(2, new Vector3f(n, n, n));
        setNormal(3, new Vector3f(-n, n, n));
        setNormal(4, new Vector3f(n, n, n));
        setNormal(5, new Vector3f(-n, n, n));
        setNormal(6, new Vector3f(-n, n, n));
        setNormal(7, new Vector3f(n, n, n));

        int[] norms = {0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7};
        setCoordinateIndices(0, coords);
        setNormalIndices(0, norms);

    }

}
import javax.vecmath.*;  
import java.awt.*;
import java.awt.event.*;
import javax.media.j3d.*;
import com.sun.j3d.utils.universe.*;
import com.sun.j3d.utils.geometry.*;
import java.applet.*;
import com.sun.j3d.utils.applet.MainFrame;

public class TestOctahedron extends Applet {
    public static void main(String[] args){
        new MainFrame(new TestOctahedron(), 640, 480);
        }

    public void init(){
        GraphicsConfiguration gc = SimpleUniverse.getPreferredConfiguration();
        Canvas3D cv = new Canvas3D(gc);
        setLayout(new BorderLayout());
        add(cv, BorderLayout.CENTER);
        BranchGroup bg = createSceneGraph();
        bg.compile();
        SimpleUniverse su = new SimpleUniverse(cv);
        su.getViewingPlatform().setNominalViewingTransform();
        su.addBranchGraph(bg);
    }

    private BranchGroup createSceneGraph() {
        BranchGroup root = new BranchGroup();
        TransformGroup spin = new TransformGroup();
        spin.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
        root.addChild(spin);
        Appearance ap = new Appearance();
        ap.setMaterial(new Material());
        Shape3D shape = new Shape3D(new Octahedron(), ap);
        Transform3D tr = new Transform3D();
        tr.setScale(0.25);
        TransformGroup tg = new TransformGroup(tr);
        spin.addChild(tg);
        tg.addChild(shape);
        Alpha alpha = new Alpha(-1, 4000);
        RotationInterpolator rotator = new RotationInterpolator(alpha, spin);
        BoundingSphere bounds = new BoundingSphere();
        rotator.setSchedulingBounds(bounds);
        spin.addChild(rotator);
        Background background = new Background(1.0f, 1.0f, 1.0f);
        background.setApplicationBounds(bounds);
        root.addChild(background);
        AmbientLight light = new AmbientLight(true, new Color3f(Color.red));
        light.setInfluencingBounds(bounds);
        root.addChild(light);


        PointLight ptlight = new PointLight(new Color3f(Color.green), new Point3f(3f, 3f, 3f), new Point3f(1f, 0f, 0f));
        ptlight.setInfluencingBounds(bounds);
        root.addChild(ptlight);
        PointLight ptlight2 = new PointLight(new Color3f(Color.orange), new Point3f(-2f, 2f, 2f), new Point3f(1f, 0f, 0f));
        ptlight2.setInfluencingBounds(bounds);
        root.addChild(ptlight2);
           PointLight ptlight3 = new PointLight(new Color3f(Color.red),
                    new Point3f(2f,2f,-2f), new Point3f(1f,0f,0f));
                ptlight3.setInfluencingBounds(bounds);
                root.addChild(ptlight3);
            PointLight ptlight4 = new PointLight(new Color3f(Color.blue),
                    new Point3f(-2f,-2f,-2f), new Point3f(1f,0f,0f));
                ptlight4.setInfluencingBounds(bounds);
                root.addChild(ptlight4);  
        return root;

    }

}

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确保所有法线都指向“向外”。如果不是这样，那么你可以试着关闭消隐。你能简单地解释一下吗。你必须阅读背面消隐和法线。本质上，如果多边形、曲面等指向远离摄影机的方向，渲染器将不会对其进行着色，因为假定您看不到它。因此，在不检查代码中的所有内容的情况下，我建议您确保所有法线都指向远离对象的方向。或者可以使用关闭背面剔除的快捷方式。下面是一个示例：polyAttrib.setCullFace（polyattributes.CULL_NONE）；