其实两种方法都是画12个三角形画出来的，在OpenGL ES中，只支持三角形，所以任何复杂多边形都是由三角形画出来的。
第一种：顶点法：
把一个四边形当成一个面，而一个面由两个三角形组成。一个三角形是不是有3个顶点？，所以一个面就有了3+3个顶点，一个立方体有6个面，6*6个顶点
此立方体的颜色也是根据顶点所渲染，正如定义这个立方体的顶点一样，不过它的参数可不是和定义顶点的一样哦，它的参数类型是：R，G，B，A，代表的是颜色值
public class OpenGlEsDemoActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GLSurfaceView glview = new GLSurfaceView(this);
glview.setRenderer(new OpenGlRender());
setContentView(glview);
}
publicclassOpenGlRenderimplementsGLSurfaceView.Renderer{
//每一个面画两个三角形，立方体有6个面
privatefloat[] vertices={
-1.0f,1.0f,1f,// top left
-1.0f,-1.0f,1f,// bottom left
1.0f,-1.0f,1f,//top right
-1.0f,1.0f,1f,//bottom left
1.0f,-1.0f,1f,//bottom right
1.0f,1.0f,1f,//top right //前面
1.0f,1.0f,1f,
1.0f,-1.0f,1f,
1.0f,-1.0f,-1f,
1.0f,1.0f,1f,
1.0f,-1.0f,-1.0f,
1.0f,1.0f,-1f,//右面
-1.0f,1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f,1.0f,1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,1.0f,
-1.0f,1.0f,1.0f,//左面
1.0f,1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
1.0f,1.0f,-1.0f,
-1.0f,-1.0f,-1.0f,
-1.0f,1.0f,-1.0f,//后面
-1.0f,1.0f,-1.0f,// top left
-1.0f,1.0f,1.0f,//bottom left
1.0f,1.0f,-1.0f,//top right
-1.0f,1.0f,1.0f,//bottom left
1.0f,1.0f,1.0f,//top right
1.0f,1.0f,-1.0f,// -top right上面
-1.0f,-1.0f,1.0f,
-1.0f,-1.0f,-1.0f,
1.0f,-1.0f,-1.0f,
-1.0f,-1.0f,1.0f,
1.0f,-1.0f,-1.0f,
1.0f,-1.0f,1.0f,//下面
};
//立方体的顶点颜色
privatefloat[] colors={
1f,0f,0f,1f,
1f,0f,0f,1f,
1f,0f,0f,1f,
1f,0f,0f,1f,
1f,0f,0f,1f,
1f,0f,0f,1f,
1f,0f,1f,1f,
1f,0f,1f,1f,
1f,0f,1f,1f,
1f,0f,1f,1f,
1f,0f,1f,1f,
1f,0f,1f,1f,
0f,1f,0f,1f,
0f,1f,0f,1f,
0f,1f,0f,1f,
0f,1f,0f,1f,
0f,1f,0f,1f,
0f,1f,0f,1f,
0f,0f,1f,1f,
0f,0f,1f,1f,
0f,0f,1f,1f,
0f,0f,1f,1f,
0f,0f,1f,1f,
0f,0f,1f,1f,
0.5f,0f,1f,1f,
0.5f,0f,1f,1f,
0.5f,0f,1f,1f,
0.5f,0f,1f,1f,
0.5f,0f,1f,1f,
0.5f,0f,1f,1f,
1f,0f,0.5f,1f,
1f,0f,0.5f,1f,
1f,0f,0.5f,1f,
1f,0f,0.5f,1f,
1f,0f,0.5f,1f,
1f,0f,0.5f,1f,
};
FloatBuffer vertBuffer; //顶点缓冲
FloatBuffer colorBuffer; //颜色缓冲
floatrx=-70f; //旋转角度
publicOpenGlRender(){
ByteBuffer vbb=ByteBuffer.allocateDirect(vertices.length*4);
vbb.order(ByteOrder.nativeOrder());
vertBuffer=vbb.asFloatBuffer();
vertBuffer.put(vertices);
vertBuffer.position(0);
ByteBuffer cbb= ByteBuffer.allocateDirect(colors.length*4);
cbb.order(ByteOrder.nativeOrder());
colorBuffer = cbb.asFloatBuffer();
colorBuffer.put(colors);
colorBuffer.position(0);
}
publicvoidonSurfaceCreated(GL10 gl, EGLConfig config) {
//启用深度测试
gl.glEnable(GL10.GL_DEPTH_TEST);
// 所做深度测试的类型
gl.glDepthFunc(GL10.GL_DITHER);
//黑色背景
gl.glClearColor(0f, 0f, 0f,0.5f);
//启用阴影平滑
gl.glShadeModel(GL10.GL_SMOOTH);
//清除深度缓存
gl.glClearDepthf(1.0f);
gl.glEnable(GL10.GL_TEXTURE_2D);
//告诉系统对透视进行修正
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
}
publicvoiddraw(GL10 gl){
gl.glFrontFace(GL10.GL_CCW);
gl.glEnable(GL10.GL_CULL_FACE);
gl.glCullFace(GL10.GL_BACK);
//开启顶点和纹理缓冲
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
gl.glVertexPointer(3, GL10.GL_FLOAT,0, vertBuffer);
gl.glColorPointer(4, GL10.GL_FLOAT,0, colorBuffer);
gl.glLoadIdentity();
gl.glTranslatef(0,0, -5);
gl.glRotatef(45f, 0f, 1f, 0f); //往右边(y轴)倾斜45度C
gl.glRotatef(rx,1f, 0f, 0f); //往上面倾斜(x轴)倾斜,根据每次得到的角度
gl.glDrawArrays(GL10.GL_TRIANGLES,0,vertices.length);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glDisable(GL10.GL_CULL_FACE);
rx--; //旋转角度减1
}
publicvoidonDrawFrame(GL10 gl) {
// 清除深度和颜色缓存
gl.glClearColor(0f, 0f, 0f,0.5f);
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glMatrixMode(GL10.GL_MODELVIEW);//设置矩阵模式
draw(gl);
}
publicvoidonSurfaceChanged(GL10 gl,intwidth,intheight) {
gl.glViewport(0,0, width, height);
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
GLU.gluPerspective(gl,45.0f, (float)width/(float)height,0.1f,100.f);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
}
原文地址：http://blog.csdn.net/w8320273/article/details/8098970
第二种：索引法
}
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