android系统下使用openGL开发demo

对openGL早有耳闻，但是刚接触android下的opengl,做个demo学习下，


先把opengl的框架搭建起来:只要有如下几个文件，


openActivity.java     ----作为启动入口,android通过GLSurfaceView显示openGL试图，而GLSurfaceView提供了专门渲染3D的Renderer接口

GLRender.java ----渲染图形



GLImage.java  ----获取资源文件


GLRender.java  实现Renderer接口：只要实现如下方法：

public void onDrawFrame(GL10 gl); //进行图形的绘制

public void onSurfaceChanged(GL10 gl, int width, int height);

public void onSurfaceCreated(GL10 gl, EGLConfig config);


GLRender.java 代码如下：
package com.aurora.android.render;

import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import java.util.Random;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import com.aurora.android.model.GLImage;
import com.aurora.android.model.Star;


import android.opengl.GLUtils;
import android.opengl.GLSurfaceView.Renderer;
import android.view.KeyEvent;

public class GLRender implements Renderer {

public static final int num = 50;
public Star[] star = new Star[num];
Random random = new Random();
boolean key;
boolean twinkle = true;
float spin;
float zoom = -10.0f;
float tilt = 90.0f;
int texture;

int one = 0x10000;

        //纹理数据
IntBuffer coords = IntBuffer.wrap(new int[] {
0, 0,
one, 0,
one, one,
0,one });

IntBuffer vertexs = IntBuffer.wrap(new int[] {
-one, -one, 0,
one, -one, 0,
one, one, 0,
-one, one, 0 });

ByteBuffer indices = ByteBuffer.wrap(new byte[] {
1, 0, 2, 3
});

@Override
public void onDrawFrame(GL10 gl) {
// TODO Auto-generated method stub

gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glBindTexture(GL10.GL_TEXTURE_2D, texture);//绑定纹理

for (int i = 0; i < num; i++) {
gl.glLoadIdentity();

gl.glTranslatef(0.0f, 0.0f, zoom);
gl.glRotatef(tilt, 1.0f, 0.0f, 0.0f);
gl.glRotatef(star[i].angle, 0.0f, 1.0f, 0.0f);
gl.glTranslatef(star[i].dist, 0.0f, 0.0f);
gl.glRotatef(-star[i].angle, 0.0f, 1.0f, 0.0f);
gl.glRotatef(-tilt, 1.0f, 0.0f, 0.0f);

gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);//启用顶点
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);//启用着色
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);//启用纹理

if (twinkle) {//启用星星闪烁效果
                                //使用byte型数值指定一颜色
gl.glColor4f((float) star[(num - i) - 1].r / 255.0f,
(float) star[(num - i) - 1].g / 255.0f,
(float) star[(num - i) - 1].b / 255.0f, 1.0f);
gl.glVertexPointer(3, GL10.GL_FIXED, 0, vertexs);
gl.glTexCoordPointer(2, GL10.GL_FIXED, 0, coords);

{
coords.position(0);
vertexs.position(0);
indices.position(0);
                                        //绘图
gl.glDrawElements(GL10.GL_TRIANGLE_STRIP, 4,
GL10.GL_UNSIGNED_BYTE, indices);

}
                                //闪烁星星绘制完成
gl.glFinish();
}
                        //绕z轴旋转
gl.glRotatef(spin, 0.0f, 0.0f, 1.0f);

gl.glColor4f((float) star[(num - i) - 1].r / 255.0f,
(float) star[(num - i) - 1].g / 255.0f,
(float) star[(num - i) - 1].b / 255.0f, 1.0f);
gl.glVertexPointer(3, GL10.GL_FIXED, 0, vertexs);
gl.glTexCoordPointer(2, GL10.GL_FIXED, 0, coords);

{
coords.position(0);
vertexs.position(0);
indices.position(0);

gl.glDrawElements(GL10.GL_TRIANGLE_STRIP, 4,
GL10.GL_UNSIGNED_BYTE, indices);

}
gl.glFinish();

gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

spin += 0.01f;
star[i].angle += (float) (i) / (float) num;
star[i].dist -= 0.01f;
if (star[i].dist < 0.0f) {
star[i].dist += 5.0f;
star[i].r = random.nextInt(256);
star[i].g = random.nextInt(256);
star[i].b = random.nextInt(256);
}
}

}

@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
// TODO Auto-generated method stub
float ratio = (float) width / height;
gl.glViewport(0, 0, width, height);// 设置场景大小
gl.glMatrixMode(GL10.GL_PROJECTION);// 设置投影矩阵
gl.glLoadIdentity();
gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);// 设置视口大小
gl.glMatrixMode(GL10.GL_MODELVIEW);// 设置观察模式
gl.glLoadIdentity();
}

@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
// TODO Auto-generated method stub

gl.glShadeModel(GL10.GL_SMOOTH);// 启用平滑
gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);// 设置黑背景
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);// 精细的透视修正

IntBuffer intBuffer = IntBuffer.allocate(1);
gl.glGenTextures(1, intBuffer);
texture = intBuffer.get();

gl.glBindTexture(GL10.GL_TEXTURE_2D, texture);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,
GL10.GL_LINEAR);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,
GL10.GL_LINEAR);
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.mBitmap, 0);

gl.glEnable(GL10.GL_TEXTURE_2D);// 设置纹理
gl.glShadeModel(GL10.GL_SMOOTH);// 启用平滑
gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);// 设置黑背景
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);// 精细的透视修正
gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE);// 设置混合函数取半透明
gl.glEnable(GL10.GL_BLEND);// 设置混色

for (int i = 0; i < num; i++) {

Star starTemp = new Star();
starTemp.angle = 0.0f;
starTemp.dist = ((float) (i) / (float) num) * 5.0f;

starTemp.r = random.nextInt(256);
starTemp.g = random.nextInt(256);
starTemp.b = random.nextInt(256);
star[i] = starTemp;

}
}

public boolean onKeyUp(int keyCode, KeyEvent event) {
twinkle = !twinkle;
return false;
}
}

openActivity.java代码如下:
package com.aurora.android.advanced;

import com.aurora.android.model.GLImage;
import com.aurora.android.render.GLRender;

import android.app.Activity;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
import android.view.KeyEvent;

public class OpenActivity extends Activity {
GLRender render = new GLRender();

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        GLImage.load(this.getResources());
        GLSurfaceView glView = new GLSurfaceView(this);
        glView.setRenderer(render);
        setContentView(glView);
    }
   
    public boolean onKeyUp(int keyCode, KeyEvent event){
    render.onKeyUp(keyCode, event);
    return false;
    }
}

GLImage.java:

package com.aurora.android.model;

import com.aurora.android.advanced.R;

import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

public class GLImage {

public static Bitmap mBitmap;

public static void load(Resources resource){
                //获取图片资源
mBitmap = BitmapFactory.decodeResource(resource, R.drawable.star);
}
}

Star.java:星星

package com.aurora.android.model;

public class Star {

public int r,g,b; //星星RGB颜色
public float dist;//星星距离中心的距离
public float angle = 0.0f; //当前星星处的角度

}