J2ME 3D编程的第一个3D程序

// First3DMIDlet.java

package first3d;

import javax.microedition.midlet.*;

import javax.microedition.lcdui.*;

public class First3DMIDlet extends MIDlet 

{

private First3DCanvas displayable = new First3DCanvas();

public void startApp() 

{

Display.getDisplay(this).setCurrent(displayable);

}

public void pauseApp() {}
public void destroyApp(boolean unconditional) {}

}
// First3Dcanvas.java

package first3d;

import javax.microedition.lcdui.*;

import javax.microedition.m3g.*;

import java.util.*;

/**

* 第一个3D程序

*/

public class First3DCanvas extends Canvas implements Runnable 

{

/**World对象*/

private World myWorld = null;

/**Graphics3D对象*/

private Graphics3D g3d = Graphics3D.getInstance();

/**Camera对象*/

private Camera cam = null;

private int viewport_x;

private int viewport_y;

private int viewport_width;

private int viewport_height;

private long worldStartTime = 0;

//重绘时间

private int validity = 0;

public First3DCanvas() 

{

//启动重绘界面的线程

Thread thread = new Thread(this);

thread.start();

try 

{

//导入3D图片

myWorld = (World) Loader.load("/swerve.m3g")[0];

viewport_x = 0;

viewport_y = 0;

viewport_width = getWidth();

viewport_height = getHeight();

cam = myWorld.getActiveCamera();

//设置cam对象

float[] params = new float[4];

int type = cam.getProjection(params);

if (type != Camera.GENERIC) 

{

//calculate window aspect ratio

float waspect = viewport_width / viewport_height;

if (waspect < params[1]) 

{

float height = viewport_width / params[1];

viewport_height = (int) height;

viewport_y = (getHeight() - viewport_height) / 2;

}

else 

{

float width = viewport_height * params[1];

viewport_width = (int) width;

viewport_x = (getWidth() - viewport_width) / 2;

}

}

worldStartTime = System.currentTimeMillis();

}

catch (Exception e) {}

}

protected void paint(Graphics g) 

{

//清除背景

g.setColor(0x00);

g.fillRect(0, 0, getWidth(), getHeight());

//和3D对象绑定

g3d.bindTarget(g);

g3d.setViewport(viewport_x, viewport_y, viewport_width, viewport_height);

long startTime = System.currentTimeMillis() - worldStartTime;

validity = myWorld.animate((int)startTime);

try 

{

g3d.render(myWorld);

}

finally 

{

g3d.releaseTarget();

}

}
public void run() 

{

try

{

while(true)

{

//重绘图形

repaint(viewport_x, viewport_y, viewport_width, viewport_height);

}

}

catch(Exception e){}

}

}