速读原著-Android应用开发入门教程(基本的绘制)

    public class TouchRotateActivity extends Activity {
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            mGLSurfaceView = new TouchSurfaceView(this); // 建立 GLSurfaceView 
            setContentView(mGLSurfaceView); // 设置 View 到活动中
            mGLSurfaceView.requestFocus(); // 配置 GLSurfaceView 
            mGLSurfaceView.setFocusableInTouchMode(true);
        }
        //......Resume()和 onPause()方法调用 GLSurfaceView 的对应方法
        private GLSurfaceView mGLSurfaceView; // 配置 GLSurfaceView 
    }

    class TouchSurfaceView extends GLSurfaceView {
        public TouchSurfaceView(Context context) {
            super(context);
            mRenderer = new CubeRenderer(); // 建立渲染器
            setRenderer(mRenderer); // 设置渲染器
            setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
        }
        private class CubeRenderer implements GLSurfaceView.Renderer {
            // 实现渲染器接口
            public void onDrawFrame(GL10 gl) {
                // 调用 OpenGL 的标准接口进行操作
                gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
                gl.glMatrixMode(GL10.GL_MODELVIEW);
                gl.glLoadIdentity();
                gl.glTranslatef(0, 0, -3.0f);
                gl.glRotatef(mAngleX, 0, 1, 0); // 对绘制的图形进行旋转
                gl.glRotatef(mAngleY, 1, 0, 0);
                gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
                gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
                mCube.draw(gl); // 调用 draw()进行绘制
            }
        }
    }

    public void onSurfaceChanged(GL10 gl, int width, int height) {
        gl.glViewport(0, 0, width, height);
        float ratio = (float) width / height;
        gl.glMatrixMode(GL10.GL_PROJECTION);
        gl.glLoadIdentity();
        gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
    }
    public void onSurfaceCreated(GL10 gl, EGLConfig config){
         gl.glDisable(GL10.GL_DITHER);
         gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT,
            GL10.GL_FASTEST);
         gl.glClearColor(1,1,1,1);
         gl.glEnable(GL10.GL_CULL_FACE);
         gl.glShadeModel(GL10.GL_SMOOTH);
         gl.glEnable(GL10.GL_DEPTH_TEST);
    }

    @Override 
    public boolean onTrackballEvent(MotionEvent e) {
        mRenderer.mAngleX += e.getX() * TRACKBALL_SCALE_FACTOR;
        mRenderer.mAngleY += e.getY() * TRACKBALL_SCALE_FACTOR;
        requestRender();
        return true;
    }
    @Override 
    public boolean onTouchEvent(MotionEvent e) {
        float x = e.getX();
        float y = e.getY();
        switch (e.getAction()) {
            case MotionEvent.ACTION_MOVE:
                float dx = x - mPreviousX;
                float dy = y - mPreviousY;
                mRenderer.mAngleX += dx * TOUCH_SCALE_FACTOR;
                mRenderer.mAngleY += dy * TOUCH_SCALE_FACTOR;
                requestRender();
        }
        mPreviousX = x;
        mPreviousY = y;
        return true;
    }