JAVA3D编写添加鼠标行为的时候出现下面的错误

Question

--------------------Configuration: <Default>--------------------
Exception in thread "main" javax.media.j3d.MultipleParentException: Group.addChild: child already has a parent
    at javax.media.j3d.GroupRetained.checkValidChild(GroupRetained.java:452)
    at javax.media.j3d.GroupRetained.addChild(GroupRetained.java:461)
    at javax.media.j3d.Group.addChild(Group.java:271)
    at objLoader.createSceneGraph(objLoader.java:122)
    at objLoader.<init>(objLoader.java:164)
    at objLoader.main(objLoader.java:173)

Answer 1

是不是涉及到了parent child重载的问题？
该怎么解决呢？
public private简单改一下么？
达人帮忙啊！

Answer 2

原程序如下：import com.sun.j3d.loaders.objectfile.ObjectFile;
import com.sun.j3d.loaders.ParsingErrorException;
import com.sun.j3d.loaders.IncorrectFormatException;
import com.sun.j3d.loaders.Scene;
import java.awt.GraphicsConfiguration;
import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.event.*;
import com.sun.j3d.utils.image.TextureLoader;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.universe.*;
import com.sun.j3d.utils.behaviors.mouse.*;
import com.sun.j3d.utils.image.*;
import java.io.*;
import javax.imageio.*;
import javax.media.j3d.*;
import javax.vecmath.*;public class objLoader extends Applet {
  public BranchGroup createSceneGraph(String filename) {
     
         BranchGroup objRoot = new BranchGroup();             BoundingSphere bounds =new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);//设置涉及范围
    
             {
                Color3f bgColor = new Color3f(0.2f, 0.3f, 0.8f);//背景颜色
    Background bg = new Background(bgColor);
    bg.setApplicationBounds(bounds);
    objRoot.addChild(bg);
             }
             {
    //设置变换组
     TransformGroup objTrans1=new TransformGroup();
   
    Transform3D x = new Transform3D();
    Transform3D y = new Transform3D();
    
    
    TransformGroup xRot=new TransformGroup();
    
    xRot.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
    xRot.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
   
   
    x.rotX(Math.PI/180);   //x轴旋转
    xRot.setTransform(x);
    objRoot.addChild(xRot);
    y.rotY(Math.PI/180);
    
    objTrans1.setTransform(y);   //Y轴旋转
    objTrans1.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
    objTrans1.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
    
    xRot.addChild(objTrans1);  
   
    //定义鼠标行为
    MouseRotate behavior = new MouseRotate();
behavior.setTransformGroup(objTrans1);
    objRoot.addChild(behavior);
    behavior.setSchedulingBounds(bounds);    MouseZoom behavior2 = new MouseZoom();
    behavior2.setTransformGroup(objTrans1);
    objRoot.addChild(behavior2);
    behavior2.setSchedulingBounds(bounds);    MouseTranslate behavior3 = new MouseTranslate();
    behavior3.setTransformGroup(objTrans1);
    objRoot.addChild(behavior3);
    behavior3.setSchedulingBounds(bounds);}
       
    
    
    {
    
    
    //整体光设置
    Color3f light1Color = new Color3f(0.0f, 1.0f,1.0f);
    Vector3f light1Direction  = new Vector3f(4.0f, -7.0f, -12.0f);
    Color3f light2Color = new Color3f(0.3f, 0.3f, 0.4f);
    Vector3f light2Direction  = new Vector3f(-6.0f, -2.0f, -1.0f);
    Color3f ambientColor = new Color3f(0.1f, 0.1f, 0.1f);    // 渐变光
    AmbientLight ambientLight = new AmbientLight(ambientColor);
    ambientLight.setInfluencingBounds(bounds);
    objRoot.addChild(ambientLight);    // 定义方向光
    DirectionalLight light1= new DirectionalLight(light1Color, light1Direction);
    light1.setInfluencingBounds(bounds);
    objRoot.addChild(light1);    DirectionalLight light2 = new DirectionalLight(light2Color, light2Direction);
    light2.setInfluencingBounds(bounds);
    objRoot.addChild(light2);    
    TransformGroup objTrans2 = new TransformGroup();
    objTrans2.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
    objRoot.addChild(objTrans2);    // Create an Alpha object that goes from 0 to 1 in 8 seconds,
    // repeatedly.
    Alpha rotationAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE,
    0, 0,40000, 0, 0,   0,0, 0);    // Create a new Behavior object that will rotate the scene
    // add it into the scene graph
    
    Transform3D yAxis = new Transform3D();
    RotationInterpolator rotator =new RotationInterpolator(rotationAlpha, objTrans2, yAxis,0.0f, (float) Math.PI*2.0f);
    rotator.setSchedulingBounds(bounds);
    objTrans2.addChild(rotator);     //准备导入
    
    Transform3D objTrans3d = new Transform3D();
    objTrans2.getTransform(objTrans3d);
    objTrans2.setTransform(objTrans3d);
    objTrans2.addChild(objTrans2);    int flags = ObjectFile.RESIZE;
    ObjectFile f =  new ObjectFile(flags, (float)(49.0 * Math.PI / 30.0));    Scene s = null;
    try {
      s = f.load(filename);
 
    }
    catch (FileNotFoundException e) {
System.err.println(e);
System.exit(1);
    }
    catch (ParsingErrorException e) {
System.err.println(e);
System.exit(1);
    }
    catch (IncorrectFormatException e) {
System.err.println(e);
System.exit(1);
    }    //sceneTG.addChild(f);
    objTrans2.addChild(s.getSceneGroup());    return objRoot;
  }
  }
 public objLoader(String filename) {
    filename="a.obj";                //定义viewplatform
  setLayout(new BorderLayout());
  GraphicsConfiguration config=SimpleUniverse.getPreferredConfiguration();
  Canvas3D c=new Canvas3D(config);
  add("Center",c);
  Viewer viewer=new Viewer(c);
  Vector3d viewpoint=new Vector3d(.0,.0,3.0);
  Transform3D t=new Transform3D();
  t.set(viewpoint);
  ViewingPlatform v=new ViewingPlatform();
  v.getViewPlatformTransform().setTransform(t);
  
  BranchGroup scene=createSceneGraph(filename);
  SimpleUniverse u=new SimpleUniverse(v,viewer);
  u.getViewingPlatform();
  u.addBranchGraph(scene);
 }  public static void main(String[] args) {
      new MainFrame(new objLoader(null), 800, 600);
  }
}

Answer 3

异常不是已经说得很清楚了吗？一个child只能有一个parent。

Answer 4

在准备导入里 objTrans2.addChild(objTrans2); 不要,还有就是你把鼠标事件加错Transfrom3D了,要添加鼠标事件先要删掉旋转的代码
我将可运行的代码发在这
import com.sun.j3d.loaders.objectfile.ObjectFile;
import com.sun.j3d.loaders.ParsingErrorException;
import com.sun.j3d.loaders.IncorrectFormatException;
import com.sun.j3d.loaders.Scene;
import java.awt.GraphicsConfiguration;
import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.event.*;
import com.sun.j3d.utils.image.TextureLoader;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.universe.*;
import com.sun.j3d.utils.behaviors.mouse.*;
import com.sun.j3d.utils.image.*;
import java.io.*;
import javax.imageio.*;
import javax.media.j3d.*;
import javax.vecmath.*;public class objLoader extends Applet {
  public BranchGroup createSceneGraph(String filename) {         BranchGroup objRoot = new BranchGroup();             BoundingSphere bounds =new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);//设置涉及范围             {
               Color3f bgColor = new Color3f(0.2f, 0.3f, 0.8f);//背景颜色
    Background bg = new Background(bgColor);
    bg.setApplicationBounds(bounds);
    objRoot.addChild(bg);
             }
             {
    //设置变换组
     TransformGroup objTrans1=new TransformGroup();    Transform3D x = new Transform3D();
    Transform3D y = new Transform3D();
    TransformGroup xRot=new TransformGroup();    xRot.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
    xRot.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
    x.rotX(Math.PI/180);   //x轴旋转
    xRot.setTransform(x);
    objRoot.addChild(xRot);
    y.rotY(Math.PI/180);    objTrans1.setTransform(y);   //Y轴旋转
    objTrans1.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
    objTrans1.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);   xRot.addChild(objTrans1);    //定义鼠标行为
//    MouseRotate behavior = new MouseRotate();
//    behavior.setTransformGroup(objTrans1);
//    objRoot.addChild(behavior);
//    behavior.setSchedulingBounds(bounds);//    MouseZoom behavior2 = new MouseZoom();
//    behavior2.setTransformGroup(objTrans1);
//    objRoot.addChild(behavior2);
//    behavior2.setSchedulingBounds(bounds);//    MouseTranslate behavior3 = new MouseTranslate();
//    behavior3.setTransformGroup(objTrans1);
//    objRoot.addChild(behavior3);
//    behavior3.setSchedulingBounds(bounds);
  }
  {
    //整体光设置
    Color3f light1Color = new Color3f(0.0f, 1.0f,1.0f);
    Vector3f light1Direction  = new Vector3f(4.0f, -7.0f, -12.0f);
    Color3f light2Color = new Color3f(0.3f, 0.3f, 0.4f);
    Vector3f light2Direction  = new Vector3f(-6.0f, -2.0f, -1.0f);
    Color3f ambientColor = new Color3f(0.1f, 0.1f, 0.1f);    // 渐变光
    AmbientLight ambientLight = new AmbientLight(ambientColor);
    ambientLight.setInfluencingBounds(bounds);
    objRoot.addChild(ambientLight);    // 定义方向光
    DirectionalLight light1= new DirectionalLight(light1Color, light1Direction);
    light1.setInfluencingBounds(bounds);
    objRoot.addChild(light1);    DirectionalLight light2 = new DirectionalLight(light2Color, light2Direction);
    light2.setInfluencingBounds(bounds);
    objRoot.addChild(light2);
    TransformGroup objTrans2 = new TransformGroup();
    objTrans2.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
    objRoot.addChild(objTrans2);    // Create an Alpha object that goes from 0 to 1 in 8 seconds,
    // repeatedly.
    Alpha rotationAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE,
    0, 0,40000, 0, 0,   0,0, 0);    // Create a new Behavior object that will rotate the scene
    // add it into the scene graph//    Transform3D yAxis = new Transform3D();
//    RotationInterpolator rotator =new RotationInterpolator(rotationAlpha, objTrans2, yAxis,0.0f, (float) Math.PI*2.0f);
//    rotator.setSchedulingBounds(bounds);
//    objTrans2.addChild(rotator);     //准备导入    Transform3D objTrans3d = new Transform3D();
    objTrans2.getTransform(objTrans3d);
    objTrans2.setTransform(objTrans3d);
    //objTrans2.addChild(objTrans2);    int flags = ObjectFile.RESIZE;
    ObjectFile f =  new ObjectFile(flags, (float)(49.0 * Math.PI / 30.0));    Scene s = null;
    try {
      s = f.load(filename);    }
    catch (FileNotFoundException e) {
      System.err.println(e);
      System.exit(1);
    }
    catch (ParsingErrorException e) {
      System.err.println(e);
      System.exit(1);
    }
    catch (IncorrectFormatException e) {
      System.err.println(e);
      System.exit(1);
    }    //sceneTG.addChild(f);    MouseRotate behavior = new MouseRotate();
    behavior.setTransformGroup(objTrans2);
    objRoot.addChild(behavior);
    behavior.setSchedulingBounds(bounds);
    objTrans2.addChild(s.getSceneGroup());    return objRoot;
  }
  }
 public objLoader(String filename) {
    filename="pao.obj";                //定义viewplatform
  setLayout(new BorderLayout());
  GraphicsConfiguration config=SimpleUniverse.getPreferredConfiguration();
  Canvas3D c=new Canvas3D(config);
  add("Center",c);
  Viewer viewer=new Viewer(c);
  Vector3d viewpoint=new Vector3d(.0,.0,3.0);
  Transform3D t=new Transform3D();
  t.set(viewpoint);
  ViewingPlatform v=new ViewingPlatform();
  v.getViewPlatformTransform().setTransform(t);  BranchGroup scene=createSceneGraph(filename);
  SimpleUniverse u=new SimpleUniverse(v,viewer);
  u.getViewingPlatform();
  u.addBranchGraph(scene);
 }  public static void main(String[] args) {
      new MainFrame(new objLoader(null), 800, 600);
  }
}

Answer 5

java3D要是在浏览器中运行装了JRE后为什么不能运行呀，提示找不到javax.media.j3d