至顶网›软件频道 ›利用J2ME开发移动3D游戏之3D图形API

利用J2ME开发移动3D游戏之3D图形API

扫一扫
分享文章到微信
扫一扫
关注官方公众号
至顶头条

JSR 184对于可以运行MIDP 2.0的设备来说，是一个节省时间和空间的可选的软件开发包。它允许开发者使用两种图形方式-保留模式和立即模式-来产生3D图形。本文集中讲述了立即模式，并给出一个例子程序来说明怎样使用3D API。

作者：朱先忠编译来源：天极 2007年9月4日

关键字：

列表2显示了MyCanvas类，该类包含了应用程序的所有图形逻辑。init()方法负责结点的创建，纹理文件的装载并设置纹理，外观和背景也被一起设置。paint()方法负责着色并旋转立方体。图1展示了正在一个模拟器中运行的实际程序。

列表2. MyCanvas类

import javax.microedition.lcdui.*;

import javax.microedition.m3g.*;

public class MyCanvas extends Canvas {

　private Graphics3D graphics3d;

　private Camera camera;

　private Light light;

　private float angle = 0.0f;

　private Transform transform = new Transform();

　private Background background = new Background();

　private VertexBuffer vbuffer;

　private IndexBuffer indexbuffer;

　private Appearance appearance;

　private Material material = new Material();

　private Image image;

　public MyCanvas() {

// 创建Displayable对象以探听命令事件

setCommandListener(new CommandListener() {

　public void commandAction(Command c, Displayable d) {

if (c.getCommandType() == Command.EXIT) {

　MIDletMain.quitApp();}}

　});

　try { init();}

　catch(Exception e) { e.printStackTrace();}

　}

　/**

　* 组件的初始化

　*/

　private void init() throws Exception {

addCommand(new Command("Exit", Command.EXIT, 1));

graphics3d = Graphics3D.getInstance();

camera = new Camera();

camera.setPerspective( 60.0f,(float)getWidth()/ (float)getHeight(), 1.0f, 1000.0f );

light = new Light();

light.setColor(0xffffff);

light.setIntensity(1.25f);

short[] vert = {

　5, 5, 5, -5, 5, 5, 5,-5, 5, -5,-5, 5,

　-5, 5,-5, 5, 5,-5, -5,-5,-5, 5,-5,-5,

　-5, 5, 5, -5, 5,-5, -5,-5, 5, -5,-5,-5,

　5, 5,-5, 5, 5, 5, 5,-5,-5, 5,-5, 5,

　5, 5,-5, -5, 5,-5, 5, 5, 5, -5, 5, 5,

　5,-5, 5, -5,-5, 5, 5,-5,-5, -5,-5,-5 };

VertexArray vertArray = new VertexArray(vert.length / 3, 3, 2);

vertArray.set(0, vert.length/3, vert);

//立方体的各个结点法线

byte[] norm = {

　0, 0, 127, 0, 0, 127, 0, 0, 127, 0, 0, 127,

　0, 0,-127, 0, 0,-127, 0, 0,-127, 0, 0,-127,

　-127, 0, 0, -127, 0, 0, -127, 0, 0, -127, 0, 0,

　127, 0, 0, 127, 0, 0, 127, 0, 0, 127, 0, 0,

　0, 127, 0, 0, 127, 0, 0, 127, 0, 0, 127, 0,

　0,-127, 0, 0,-127, 0, 0,-127, 0, 0,-127, 0 };

VertexArray normArray = new VertexArray(norm.length / 3, 3, 1);

normArray.set(0, norm.length/3, norm);

//各个结点的纹理坐标

short[] tex = {

　1, 0, 0, 0, 1, 1, 0, 1,

　1, 0, 0, 0, 1, 1, 0, 1,

　1, 0, 0, 0, 1, 1, 0, 1,

　1, 0, 0, 0, 1, 1, 0, 1,

　1, 0, 0, 0, 1, 1, 0, 1,

　1, 0, 0, 0, 1, 1, 0, 1 };

VertexArray texArray = new VertexArray(tex.length / 2, 2, 2);

texArray.set(0, tex.length/2, tex);

int[] stripLen = { 4, 4, 4, 4, 4, 4 };

// 对象的VertexBuffer

VertexBuffer vb = vbuffer = new VertexBuffer();

vb.setPositions(vertArray, 1.0f, null);

vb.setNormals(normArray);

vb.setTexCoords(0, texArray, 1.0f, null);

indexbuffer = new TriangleStripArray( 0, stripLen );

//纹理图像

image = Image.createImage( "/pic1.png" );

Image2D image2D = new Image2D( Image2D.RGB, image );

Texture2D texture = new Texture2D( image2D );

texture.setFiltering(Texture2D.FILTER_NEAREST,

Texture2D.FILTER_NEAREST);

texture.setWrapping(Texture2D.WRAP_CLAMP,Texture2D.WRAP_CLAMP);

texture.setBlending(Texture2D.FUNC_MODULATE);

// 创建外观（Appearance）对象

appearance = new Appearance();

appearance.setTexture(0, texture);

appearance.setMaterial(material);

material.setColor(Material.DIFFUSE, 0xFFFFFFFF);

material.setColor(Material.SPECULAR, 0xFFFFFFFF);

material.setShininess(100.0f);

background.setColor(0xffffcc);

　}

　protected void paint(Graphics g) {

graphics3d.bindTarget(g, true,

　Graphics3D.DITHER |

　Graphics3D.TRUE_COLOR);

　graphics3d.clear(background);

//设置照相机

Transform transform = new Transform();

transform.postTranslate(0.0f, 0.0f, 30.0f);

graphics3d.setCamera(camera, transform);

//设置灯光

graphics3d.resetLights();

graphics3d.addLight(light, transform);

//设置旋转

angle += 1.0f;

transform.setIdentity();

transform.postRotate(angle, 1.0f, 1.0f, 1.0f);

graphics3d.render(vbuffer, indexbuffer, appearance, transform);

graphics3d.releaseTarget();

　}

}

图1 正在一个模拟器中运行的应用程序