fogdemo.java

人民邮电出版社的《J2ME手机开发入门》全部源代码

/*
 * FogDemo.java
 *
 */

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;

import javax.microedition.m3g.*;

public class FogDemo extends MIDlet implements CommandListener{
    private Command cmdExit;
    private Display d;
    private M3GCanvas m3gCanvas;
    
    public FogDemo(){
        d = Display.getDisplay(this);
        
        cmdExit = new Command("退出", Command.EXIT, 0);
        
        m3gCanvas = new M3GCanvas();
        m3gCanvas.addCommand(cmdExit);
        m3gCanvas.setCommandListener(this);
    }
    
    public void startApp() {
        d.setCurrent(m3gCanvas);
    }
    
    public void pauseApp() {
        
    }
    
    public void destroyApp(boolean unconditional) {
        
    }
    public void commandAction(Command c, Displayable d){
        notifyDestroyed();
    }
    
}

class M3GCanvas extends GameCanvas implements Runnable{
    
    private Graphics3D g3d;
    private World world;
    private Camera camera;
    private Mesh pyramidMesh;
    
    private  Fog fog;
    
    public M3GCanvas(){
        super(false);
        
        g3d = Graphics3D.getInstance();
        world = new World();
        
        //创建并添加摄像机
        camera = new Camera();
        float w = getWidth();
        float h = getHeight();
        camera.setPerspective(60.0f,  w/h, 0.1f, 50f);
        world.addChild(camera);
        world.setActiveCamera(camera);
        
        //创建并添加金字塔对象
        pyramidMesh = createpyramid();
        pyramidMesh.setTranslation(0.0f, 0.0f, -3.5f);
        world.addChild(pyramidMesh);
        
        Thread t = new Thread(this);
        t.start();
    }
    
    public void run() {
        Graphics g = getGraphics();
        
        while(true){
            //调整fog浓度和颜色
            int keyState = getKeyStates();
            if ((keyState & LEFT_PRESSED) != 0) {
                fog.setDensity(fog.getDensity()+0.01f);
                System.out.println("当前浓度值为：" + fog.getDensity());
            } else if ((keyState & RIGHT_PRESSED) != 0) {
                float den = fog.getDensity()- 0.01f;
                if (den <0) {
                    den = 0;
                }
                fog.setDensity(den);
                System.out.println("当前浓度值为：" + fog.getDensity());
            } else if ((keyState & UP_PRESSED) != 0) {
                fog.setColor(fog.getColor()+100);
                System.out.println("当前颜色值为：" + fog.getColor());
            } else if ((keyState & DOWN_PRESSED) != 0) {
                fog.setColor(fog.getColor()-100);
                System.out.println("当前颜色值为：" + fog.getColor());
            }
            //绕y轴旋转3度
            pyramidMesh.postRotate(3.0f, 0.0f, 1.0f, 0.0f);
            
            try{
                g3d.bindTarget(g);
                g3d.render(world);
            }finally{
                g3d.releaseTarget();
            }
            
            flushGraphics();
            
            try {
                Thread.sleep(100);
            }  catch (Exception e) {
            }
        }
    }
    
    
    // this method creates a colored pyramid.
    private Mesh createpyramid(){
        
        //金字塔的顶点坐标
        short []POINTS = new short[] {-1, -1, 1,   //点0
                1, -1, 1,                           //点1
                1, -1, -1,                          //点2
                -1, -1, -1,                         //点3
                0, 1, 0                             //点4（顶点）
        };
        
        
        //外部索引
        int []INDICES = new int[] {
            0, 1, 4, 1, 2, 4, 2, 3, 4, 3, 0, 4, 2, 1, 0, 2, 0, 3
        };
        
        //定义顶点的颜色
        byte []COLORS = new byte[] {127, 0, 0, //红色
                0, 127, 0,                      //绿色
                0, 0, 127,                      //蓝色
                127, 0, 127,
                0, 127, 127
        };
        
        //金字塔由六个三角形组成（地面为两个三角形）
        //指定索引数组中每个顺序的长度，下面两个语句都可以
        int[] stripLen = new int[] {3, 3, 3, 3, 4};
        //int[] stripLen = new int[] {3, 3, 3, 3, 3, 3};
        
        //创建VertexArray
        //在创建VertexBuffer时要使用VertexArray
        VertexArray vaVertex = new VertexArray(POINTS.length / 3, 3, 2);
        vaVertex.set(0, POINTS.length / 3, POINTS);
        VertexArray vaColors = new VertexArray(COLORS.length / 3, 3, 1);
        vaColors.set(0, COLORS.length / 3, COLORS);
        
        //以外部索引创建IndexBuffer
        IndexBuffer ibPyramid = new TriangleStripArray(INDICES, stripLen);
        
        //创建VertexBuffer对象
        VertexBuffer vertexBuffer = new VertexBuffer();
        vertexBuffer.setPositions(vaVertex, 1.0f, null);  //设置顶点坐标
        vertexBuffer.setColors(vaColors);                  //设置颜色
        
        //创建一个Mesh对象
        Mesh mesh = new Mesh(vertexBuffer, ibPyramid, null);
        
        //创建fog对象
        fog = new Fog();
        fog.setColor(0x00103F0B);
        //fog.setLinear(0.2f, 1.0f);
        fog.setMode(Fog.EXPONENTIAL);
        fog.setDensity(0.0f);
        
        //创建外表Appearance对象
        Appearance appearance = new Appearance();
        appearance.setFog(fog);
        mesh.setAppearance(0, appearance); 
        return mesh;
    }
    
}