在Java 3D中载入外部3D模型文件.doc

1、在 Java 3D 中载入外部 3DJava 3D 虽然能支持众多的外部 3D 模型文件，但能支持被 Java 3D 使用的外部模型文件仅为.obj 和.lwd 两种；分别对应ObjectFile 类和 Lw3dLoader 类。相比之下几款主流的 3D 建模软件都能生成.obj 格式的文件，因此本文主要介绍使用 ObjectFile 类载入.obj 文件的方法。ObjectFile 类有三个构造方法，分别为：ObjectFile() ObjectFile(int flags) ObjectFile(int flags, float radians) 其中 flags 为一个整型的常量参数，用

2、于决定载入的 3D 模型以什么方式生成。参数 radians 用于决定载入模型的可显示半径。flags 参数可在以下四个值之间任取一个或者用逻辑或（“|“ ）将几个参数组合使用。ObjectFile.RESIZE：忽略被载入的模型大小，直接把载入的模型放在一个范围在(1,1,1) 到(-1,-1,-1)之间的立方体空间内，并把坐标原点设为(0,0,0)。ObjectFile.REVERSE：反转载入的外部模型，即可能看模型的后面。ObjectFile.TRIANGULATE：将模型的面以三角形方式显示，此参数主要便于观察模型凹凸面。ObjectFile.STRIPIFY：以模型文件内模型的实际

3、情况显示，此参数也是默认参数。当初始化了 ObjectFile 对象后就可以用 load 方法载入.obj 格式的文件，如果模型中已包含了贴图和光照的话也将一起被载入。load 方法需要一个参数用于指出.obj 格式文件所在的路径，load 方法有多个重载方法可以使参数即可以接受String 类的值也可以接受 Url 类的值或者从输入法流读入，如果模型载入成功将返回一个 Scene 类的对象，如果载入失败将抛异常。Java 3D 针对 load 方法定义了三个异常类：FileNotFoundException 类：表示文件未找到。IncorrectFormatException 类：表示文件格

4、式不正确。ParsingErrorException 类：装载器解析文件时出错。下面的代码用以演示如何用 load 方法将一个模型载入到 Scene 类的实例：view plaincopy to clipboardprint?Scene loadScene = null; int flag = ObjectFile.STRIPIFY; ObjectFile obj = new ObjectFile(flag); try loadScene = obj.load(this.getClass().getClassLoader().getResource(filename); catch (File

5、NotFoundException e) System.out.println(“文件未找到或文件路径不正确 “); e.printStackTrace(); catch (IncorrectFormatException e) System.out.println(“文件格式不正确“); e.printStackTrace(); catch (ParsingErrorException e) System.out.println(“装载器解析文件时出错“); e.printStackTrace(); Scene loadScene = null;int flag = ObjectFile.S

6、TRIPIFY;ObjectFile obj = new ObjectFile(flag);try loadScene = obj.load(this.getClass().getClassLoader().getResource(filename); catch (FileNotFoundException e) System.out.println(“文件未找到或文件路径不正确 “);e.printStackTrace(); catch (IncorrectFormatException e) System.out.println(“文件格式不正确“);e.printStackTrace(

7、); catch (ParsingErrorException e) System.out.println(“装载器解析文件时出错“);e.printStackTrace(); 虽然至此我们已经载入了一个.obj 格式文件的 3D 模型，但把它载入到场景后我们却模型并没有按我们想像的那么显示。对比在 3D 建模工具中看到模型的样子，我们的模型被绕 X 轴逆时针的旋转了 90 度，这主要是 Java 3D 的坐标系和大多数的 3D 建模工具的坐标系不同。我们假设用户的显示器是垂直于桌面上，那么在Java 3D 中显示器的宽代表 X 轴，显示器的高代表 Y 轴，显示器垂直朝向用户的方法为 Z 轴（

8、此方向也是 Z 轴的正数方向）。而多数的建模工具使用的是世界坐标系，即将显示器的高代表 Z 轴。因此我们需要在程序将模型绕 X 轴顺时针旋转 90 度，旋转轴坐标的方法是使用Transform3D 类的 rotX 方法，相应的还有 rotY 和 rotZ 方法。view plaincopy to clipboardprint?Transform3D t3d = new Transform3D(); t3d.rotX(-Math.PI/2); TransformGroup tg = new TransformGroup(t3d); tg.addChild(loadScene.getSceneGr

9、oup); Transform3D t3d = new Transform3D();t3d.rotX(-Math.PI/2);TransformGroup tg = new TransformGroup(t3d);tg.addChild(loadScene.getSceneGroup);注意：这里有一个容易混淆的概念，就是我们刚才的步骤是旋转的坐标系，而不是模型，模型是附加在坐标系的上，没有法被旋转。而在刚才的步骤完成后就是将Z 轴转向了上方（即显示器的高），而此时场中如还有其它的模型的话，它们的坐标未受影响，仍是 Java 3D 的坐标系。通常情况下我们载入的模型大小并不是我们所要的，我们必

10、须要在场景中对模型进行缩放操作。Java 3D 中对模型进行缩放需要用到 Transform3D 的setScale 方法，方法可以接收一个 double 值或一个 Vector3d 对象的实例，当使用 double 值做参数时模型将在 XYZ 轴上使用同样的比例因子进行缩放，而Vector3d 实例则可以分别为 XYZ 轴指定不同的比例因子，比例因子越接近 0，模型就越小，当设为 0 时模型即小的不可见了。t3d.setScale(0.05d);或t3d.setScale(new Vector3d(0.01d,0,02d,0.03d);好了，现在我将代码整理如下：Gamemain.java

11、程序主入口ScreenManager.java 窗口框架类LoadModelDemo.java 演示载入一个外部 3D 模型文件ColourTile.java 实现一个平面用于地面中的单块地砖CheckedFloor.java 实现场景中的地面GameMain.javaview plaincopy to clipboardprint?import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.swing.JFrame; import javax.swing.JOptionPane; i

12、mport javax.swing.JPanel; public class GameMain private static int scrWidth = 800; private static int scrHeight = 600; private static int scrBitdepth = 32; private JFrame gameFrame; private JPanel gamePanel; public static void main(String args) GameMain game = new GameMain(); public GameMain() Scree

13、nManager screen = new ScreenManager(scrWidth,scrHeight,scrBitdepth,“Java 3D Test“); screen.setWindowMode(); gameFrame = screen.getFrame(); gamePanel = new LoadModelDemo(scrWidth,scrHeight); gameFrame.add(gamePanel); import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import javax.s

14、wing.JFrame;import javax.swing.JOptionPane;import javax.swing.JPanel;public class GameMain private static int scrWidth = 800;private static int scrHeight = 600;private static int scrBitdepth = 32;private JFrame gameFrame;private JPanel gamePanel;public static void main(String args)GameMain game = ne

15、w GameMain();public GameMain()ScreenManager screen = new ScreenManager(scrWidth,scrHeight,scrBitdepth,“Java 3D Test“);screen.setWindowMode();gameFrame = screen.getFrame();gamePanel = new LoadModelDemo(scrWidth,scrHeight);gameFrame.add(gamePanel);ScreenManager.javaview plaincopy to clipboardprint?imp

16、ort java.awt.Dimension; import java.awt.DisplayMode; import java.awt.GraphicsDevice; import java.awt.GraphicsEnvironment; import java.awt.Insets; import java.awt.Toolkit; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import javax.swing.JFrame; import javax.swing.JOptionPane

17、; public class ScreenManager private GraphicsDevice device; private JFrame frame; private String title; private boolean isResizable; private boolean isWindowMode; private int scrWidth; private int scrHeight; private int scrBitdepth; public ScreenManager(int scrWidth,int scrHeight,int scrBitdepth,Str

18、ing title) this.scrWidth = scrWidth; this.scrHeight = scrHeight; this.scrBitdepth = scrBitdepth; this.title = title; public ScreenManager(String title) this.title = title; this.frame.setTitle(title); public void setFullScreenMode() device = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaul

19、tScreenDevice(); if(isSupportDisplayMode(scrWidth,scrHeight,scrBitdepth) frame = new JFrame(); frame.setUndecorated(true); frame.setResizable(false); frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE); frame.setVisible(true); device.setFullScreenWindow(frame); try if(device.isFullScreenSuppo

20、rted() catch(IllegalArgumentException e) e.printStackTrace(); System.exit(0); else JOptionPane.showMessageDialog(null, “不支持的显示分辨率!“,“错误“,JOptionPane.ERROR_MESSAGE); System.exit(0); private boolean isSupportDisplayMode(int width,int height,int bitdepth) DisplayMode modes = device.getDisplayModes(); f

21、or(DisplayMode mode : modes) if(mode.getWidth()=width return false; public void setWindowMode() frame = new JFrame(); frame.setResizable(false);/禁止窗体改变大小 frame.setPreferredSize(new Dimension(scrWidth,scrHeight); frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);/响应窗体的关闭事件，但不关闭窗体 frame.setVi

22、sible(true); / 侦听窗体事件并捕获窗体关闭中的事件，在用户确认后退出程序 frame.addWindowListener(new WindowAdapter() public void windowClosing(WindowEvent e) int res = JOptionPane.showConfirmDialog(null, “是否退出！“,“退出“,JOptionPane.YES_NO_OPTION); if(res = JOptionPane.YES_OPTION) closeFrame(); ); this.setFrametoCenter(); public vo

23、id setFullWindowMode() if(frame != null) device = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice(); DisplayMode displayMode = device.getDisplayMode(); frame.setPreferredSize(new Dimension(displayMode.getWidth(),displayMode.getHeight(); public int getWidth() return scrWidth;

24、 public int getHeight() return scrHeight; public JFrame getFrame() return frame; / 将窗体在显示屏幕内居中显示 public void setFrametoCenter() if(device!=null) return; Insets inset = frame.getInsets(); int scrx=0; int scry=0; Dimension scrSize = Toolkit.getDefaultToolkit().getScreenSize(); if(scrSize.width scrWidt

25、h) scrx = (scrSize.width-scrWidth)/2; if(scrSize.height scrHeight) scry = (scrSize.height-scrHeight)/2; frame.setBounds(scrx-inset.left, scry-inset.top, scrWidth+inset.right+inset.left, scrHeight+inset.bottom+inset.top); / 关闭窗体事件 public void closeFrame() frame.dispose(); System.exit(0); import java.

26、awt.Dimension;import java.awt.DisplayMode;import java.awt.GraphicsDevice;import java.awt.GraphicsEnvironment;import java.awt.Insets;import java.awt.Toolkit;import java.awt.event.WindowAdapter;import java.awt.event.WindowEvent;import javax.swing.JFrame;import javax.swing.JOptionPane;public class Scre

27、enManager private GraphicsDevice device;private JFrame frame;private String title;private boolean isResizable;private boolean isWindowMode;private int scrWidth;private int scrHeight;private int scrBitdepth;public ScreenManager(int scrWidth,int scrHeight,int scrBitdepth,String title)this.scrWidth = s

28、crWidth;this.scrHeight = scrHeight;this.scrBitdepth = scrBitdepth;this.title = title;public ScreenManager(String title)this.title = title;this.frame.setTitle(title);public void setFullScreenMode()device = GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice();if(isSupportDisplayM

29、ode(scrWidth,scrHeight,scrBitdepth)frame = new JFrame();frame.setUndecorated(true);frame.setResizable(false);frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);frame.setVisible(true);device.setFullScreenWindow(frame);tryif(device.isFullScreenSupported()catch(IllegalArgumentException e)e.prin

30、tStackTrace();System.exit(0);elseJOptionPane.showMessageDialog(null, “不支持的显示分辨率!“,“错误“,JOptionPane.ERROR_MESSAGE);System.exit(0);private boolean isSupportDisplayMode(int width,int height,int bitdepth)DisplayMode modes = device.getDisplayModes();for(DisplayMode mode : modes)if(mode.getWidth()=width r

31、eturn false;public void setWindowMode()frame = new JFrame();frame.setResizable(false);/禁止窗体改变大小frame.setPreferredSize(new Dimension(scrWidth,scrHeight);frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);/响应窗体的关闭事件，但不关闭窗体frame.setVisible(true);/ 侦听窗体事件并捕获窗体关闭中的事件，在用户确认后退出程序frame.addWindowList

32、ener(new WindowAdapter()public void windowClosing(WindowEvent e)int res = JOptionPane.showConfirmDialog(null, “是否退出！“,“退出“,JOptionPane.YES_NO_OPTION);if(res = JOptionPane.YES_OPTION)closeFrame(););this.setFrametoCenter();public void setFullWindowMode()if(frame != null)device = GraphicsEnvironment.ge

33、tLocalGraphicsEnvironment().getDefaultScreenDevice();DisplayMode displayMode = device.getDisplayMode();frame.setPreferredSize(new Dimension(displayMode.getWidth(),displayMode.getHeight();public int getWidth()return scrWidth;public int getHeight()return scrHeight;public JFrame getFrame()return frame;

34、/ 将窗体在显示屏幕内居中显示public void setFrametoCenter()if(device!=null)return;Insets inset = frame.getInsets();int scrx=0;int scry=0;Dimension scrSize = Toolkit.getDefaultToolkit().getScreenSize();if(scrSize.width scrWidth)scrx = (scrSize.width-scrWidth)/2;if(scrSize.height scrHeight)scry = (scrSize.height-sc

35、rHeight)/2;frame.setBounds(scrx-inset.left, scry-inset.top, scrWidth+inset.right+inset.left, scrHeight+inset.bottom+inset.top);/ 关闭窗体事件public void closeFrame()frame.dispose();System.exit(0);LoadModelDemo.javaview plaincopy to clipboardprint?import java.awt.BorderLayout; import java.awt.Dimension; im

36、port java.awt.Font; import java.awt.GraphicsConfiguration; import java.io.FileNotFoundException; import java.util.Enumeration; import javax.media.j3d.Background; import javax.media.j3d.BoundingBox; import javax.media.j3d.BoundingSphere; import javax.media.j3d.BranchGroup; import javax.media.j3d.Canv

37、as3D; import javax.media.j3d.Transform3D; import javax.media.j3d.TransformGroup; import javax.swing.JPanel; import javax.vecmath.Color3f; import javax.vecmath.Point3d; import javax.vecmath.Vector3d; import javax.vecmath.Vector3f; import com.sun.j3d.loaders.IncorrectFormatException; import com.sun.j3

38、d.loaders.ParsingErrorException; import com.sun.j3d.loaders.Scene; import com.sun.j3d.loaders.objectfile.ObjectFile; import com.sun.j3d.utils.behaviors.vp.OrbitBehavior; import com.sun.j3d.utils.geometry.Text2D; import com.sun.j3d.utils.universe.SimpleUniverse; import com.sun.j3d.utils.universe.View

39、ingPlatform; public class LoadModelDemo extends JPanel private BranchGroup sceneBG; private SimpleUniverse universe; private BoundingSphere bounds; private double boundRadius = 100; public LoadModelDemo(int width,int height) this.setLayout(new BorderLayout(); GraphicsConfiguration config = SimpleUni

40、verse.getPreferredConfiguration(); Canvas3D canvas = new Canvas3D(config); canvas.setSize(width, height); this.add(canvas,BorderLayout.CENTER); universe = new SimpleUniverse(canvas); createSceneGroup(); initUserPosition(); orbitControls(canvas); universe.addBranchGraph(sceneBG); public void createSc

41、eneGroup() sceneBG = new BranchGroup(); bounds = new BoundingSphere(new Point3d(0,0,0),boundRadius); addBackground(); TransformGroup objModel = new TransformGroup4; sceneBG.addChild(objModel0 = loadModel(“leet/Liit.obj“,ObjectFile.RESIZE,new Vector3d(-5.4,0,0); sceneBG.addChild(objModel1 = loadModel

42、(“leet/Liit.obj“,ObjectFile.REVERSE,new Vector3d(-1.8,0,0); sceneBG.addChild(objModel2 = loadModel(“leet/Liit.obj“,ObjectFile.TRIANGULATE,new Vector3d(1.8,0,0); sceneBG.addChild(objModel3 = loadModel(“leet/Liit.obj“,ObjectFile.STRIPIFY,new Vector3d(5.4,0,0); sceneBG.addChild(new CheckerFloor().getBG

43、(); /对 sceneBG 有关的对象进行编译和缓存，如果在编译之后再次添加其它分支的话将抛异常 sceneBG.compile(); public void addBackground() Background back = new Background(); back.setApplicationBounds(bounds); back.setColor(0.17f, 0.62f, 0.92f); sceneBG.addChild(back); private void initUserPosition() /返回当前虚拟世界的观察平台 ViewingPlatform vp = univ

44、erse.getViewingPlatform(); /得到观察平台的坐标枝花点 TransformGroup steerTG = vp.getViewPlatformTransform(); Transform3D t3d = new Transform3D(); steerTG.getTransform(t3d); /设置观察点坐标在(0,5,20)，看向坐标(0,0,0)处，指定 Y 轴向正数沿伸方向为正方向 t3d.lookAt(new Point3d(0,5,20), new Point3d(0,0,0), new Vector3d(0,1,0); t3d.invert(); ste

45、erTG.setTransform(t3d); private void orbitControls(Canvas3D canvas) OrbitBehavior orbit = new OrbitBehavior(canvas, OrbitBehavior.REVERSE_ALL); orbit.setSchedulingBounds(bounds); ViewingPlatform vp = universe.getViewingPlatform( ); vp.setViewPlatformBehavior(orbit); private TransformGroup loadModel(

46、String filename,int flag,Vector3d translation) Scene loadScene = this.loadFromFile(filename,flag); Transform3D t3d = new Transform3D(); t3d = this.rotateModel(); t3d.setScale(this.calcScaleFactor(loadScene.getSceneGroup(); t3d.setTranslation(translation); TransformGroup tg = new TransformGroup(t3d);

47、 tg.addChild(loadScene.getSceneGroup(); return tg; private Scene loadFromFile(String filename,int flag) Scene loadScene = null; ObjectFile obj = new ObjectFile(flag); try loadScene = obj.load(this.getClass().getClassLoader().getResource(filename); catch (FileNotFoundException e) / TODO Auto-generate

48、d catch block System.out.println(“文件未找到或文件路径不正确 “); e.printStackTrace(); catch (IncorrectFormatException e) / TODO Auto-generated catch block System.out.println(“文件格式不正确 “); e.printStackTrace(); catch (ParsingErrorException e) / TODO Auto-generated catch block System.out.println(“装载器解析文件时出错 “); e.printStackTrace(); finally return loadScene;