java 3D 第二天 场景切换续

    java 3D 第二天 场景切换中，我们需要使用SimpleUniverse的getLocale()方法的replaceBranchGroup()方法，在replaceBranchGroup()方法中有两个参数，是要切换的场景对象，参数的顺序为oldScene,newScene。

   SimpleUniverse universe = new SimpleUniverse(oldScene);

   universe.getLocal().replaceBranchGroup(oldScene,newScene);

要注意的是：切换的场景必须是设置了 setCapability(BranchGroup.ALLOW_DETACH);运行子节点从父节点中分离出去。

   这里的代码我们使用java 3D第一天 场景的介绍中将里面的场景复制一份，进行切换使用：代码如下：

package com.first.scene;

import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.GraphicsConfiguration;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.media.j3d.Appearance;
import javax.media.j3d.Background;
import javax.media.j3d.BoundingSphere;
import javax.media.j3d.BranchGroup;
import javax.media.j3d.Canvas3D;
import javax.media.j3d.DirectionalLight;
import javax.media.j3d.Material;
import javax.vecmath.Color3f;
import javax.vecmath.Point3d;
import javax.vecmath.Vector3f;

import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.geometry.ColorCube;
import com.sun.j3d.utils.geometry.Cone;
import com.sun.j3d.utils.universe.SimpleUniverse;

public class first_secen extends Applet implements ActionListener{
 SimpleUniverse universe;
 Button button;
 BranchGroup scene;
 BranchGroup scene2;
 public BranchGroup createSceneGraph(){
  BranchGroup bjRoot = new BranchGroup();
  objRoot.setCapability(BranchGroup.ALLOW_DETACH);
  BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0),100.0);
  
  Color3f bgcColor = new Color3f(1.0f,1.0f,1.0f);
  Background bg = new Background(bgcColor);
  bg.setApplicationBounds(bounds);
  objRoot.addChild(bg);
  
  Color3f DirectionalColor = new Color3f(1.f,1.f,1.f);
  Vector3f vec = new Vector3f(0.f,0.f,-1.0f);
  DirectionalLight diretcton = new DirectionalLight(DirectionalColor,vec);
  diretcton.setInfluencingBounds(bounds);
  objRoot.addChild(diretcton);
  
  Appearance app = new Appearance();
  Material material = new Material();
  material.setEmissiveColor(new Color3f(1.0f,0.0f,0.0f));
  app.setMaterial(material);
  ColorCube colorCube = new ColorCube(0.5);
  colorCube.setAppearance(app);
  objRoot.addChild(colorCube);
  
  objRoot.compile();
  return objRoot;
 }
 public BranchGroup createSceneGraph1(){
  BranchGroup bjRoot = new BranchGroup();
  objRoot.setCapability(BranchGroup.ALLOW_DETACH);
  BoundingSphere bounds = new BoundingSphere(new Point3d(0.0,0.0,0.0),100.0);
  
  Color3f bgcColor = new Color3f(1.0f,1.0f,1.0f);
  Background bg = new Background(bgcColor);
  bg.setApplicationBounds(bounds);
  objRoot.addChild(bg);
  
  Color3f DirectionalColor = new Color3f(1.f,1.f,1.f);
  Vector3f vec = new Vector3f(0.f,0.f,-1.0f);
  DirectionalLight diretcton = new DirectionalLight(DirectionalColor,vec);
  diretcton.setInfluencingBounds(bounds);
  objRoot.addChild(diretcton);
  
  Appearance app = new Appearance();
  Material material = new Material();
  material.setEmissiveColor(new Color3f(1.0f,0.0f,0.0f));
  app.setMaterial(material);
  Cone cone = new Cone(0.5f,1.0f,1,app);
  objRoot.addChild(cone);
  
  objRoot.compile();
  return objRoot;
 }
 public first_secen(){
  setLayout(new BorderLayout());
  GraphicsConfiguration config = SimpleUniverse.getPreferredConfiguration();
  Canvas3D canvas3d = new Canvas3D(config);
  add(canvas3d,BorderLayout.CENTER);
  button = new Button("change");
  add(button,BorderLayout.WEST);
  button.addActionListener(this);
  scene = createSceneGraph();
  scene2 = createSceneGraph1();
  universe = new SimpleUniverse(canvas3d);
  universe.getViewingPlatform().setNominalViewingTransform();
  universe.addBranchGraph(scene2);
 }
 
 public static void main(String[] args){
  new MainFrame(new first_secen(), 800,600);
 }
 @Override
 public void actionPerformed(ActionEvent arg0) {
  if (arg0.getSource() == button) {
   universe.getLocale().replaceBranchGraph(scene2, scene);
  }
  
 }
}

效果图如下：