Android OpenGL ES：红色三角形

public class MyRenderer implements Renderer 
{
    FloatBuffer verticesBuffer;

    @Override
    public void onDrawFrame(GL10 gl) 
    {
        gl.glViewport(0, 0, 320, 480);
        gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glOrthof(0, 320, 0, 480, 1, -1);
        
        gl.glColor4f(1, 0, 0, 1);
        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
        gl.glVertexPointer(2, GL10.GL_FLOAT, 0, verticesBuffer);
        gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);
    }

    @Override
    public void onSurfaceChanged(GL10 gl, int width, int height) 
    {

    }

    @Override
    public void onSurfaceCreated(GL10 gl, EGLConfig config) 
    {
        ByteBuffer byteBuffer = ByteBuffer.allocateDirect(3 * 2 * 4); // 3:顶点数 2:维数,x和y 4:一个float型占4个字节
        byteBuffer.order(ByteOrder.nativeOrder());
        verticesBuffer = byteBuffer.asFloatBuffer();
        verticesBuffer.put(new float[] {0, 0,
                320, 0,
                160, 480});
        verticesBuffer.flip();
    }
}

// Activity:
public class OpenGLTestActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        GLSurfaceView glSurfaceView = new GLSurfaceView(this);
        MyRenderer renderer = new MyRenderer();
        glSurfaceView.setRenderer(renderer);
        setContentView(glSurfaceView);
    }
}