android framework surface native 层渲染

status_t VideoRender::render(const void *data, size_t size,int width,int height)

{

    if(mCodecSurface==NULL){

        return BAD_VALUE ;
    }

  // 本地窗口

    sp<ANativeWindow> mNativeWindow = mSurface;

    int err;

    int mCropWidth = width;

    int mCropHeight = height;

    

    int halFormat = HAL_PIXEL_FORMAT_YCrCb_420_SP;//HAL_PIXEL_FORMAT_YV12;//颜色空间

    int bufWidth = (mCropWidth + 1) & ~1;//按2对齐

    int bufHeight = (mCropHeight + 1) & ~1;

        

    // 参数校验

    CHECK_EQ(0,

            native_window_set_usage(

            mNativeWindow.get(),

            GRALLOC_USAGE_SW_READ_NEVER | GRALLOC_USAGE_SW_WRITE_OFTEN

            | GRALLOC_USAGE_HW_TEXTURE | GRALLOC_USAGE_EXTERNAL_DISP));

    CHECK_EQ(0,

            native_window_set_scaling_mode(

            mNativeWindow.get(),

            NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW));

    // Width must be multiple of 32???

    //很重要,配置宽高和和指定颜色空间yuv420

    //如果这里不配置好，下面deque_buffer只能去申请一个默认宽高的图形缓冲区

    CHECK_EQ(0, native_window_set_buffers_geometry(

                mNativeWindow.get(),

                bufWidth,

                bufHeight,

                halFormat));

    

    ANativeWindowBuffer *buf;//描述buffer

    //申请一块空闲的图形缓冲区

    if ((err = native_window_dequeue_buffer_and_wait(mNativeWindow.get(),

            &buf)) != 0) {

        ALOGW("%d----->Surface::dequeueBuffer returned error %d", mIndex, err);

        return BAD_VALUE;

    }

    

//    sp<GraphicBuffer> graphicBuffer(new GraphicBuffer(buf, false));

    GraphicBufferMapper &mapper = GraphicBufferMapper::get();

    Rect bounds(mCropWidth, mCropHeight);

    void *dst;

    CHECK_EQ(0, mapper.lock(//用来锁定一个图形缓冲区并将缓冲区映射到用户进程

                buf->handle, GRALLOC_USAGE_SW_WRITE_OFTEN, bounds, &dst));//dst就指向图形缓冲区首地址

    if (true){

        size_t dst_y_size = buf->stride * buf->height;

        size_t dst_c_stride = ALIGN(buf->stride / 2, 16);//1行v/u的大小

        size_t dst_c_size = dst_c_stride * buf->height / 2;//u/v的大小

     //   ALOGD(" %d: %d %d!",mIndex,buf->stride,buf->height);

     //   memcpy(dst, data, dst_y_size + dst_c_size*2);//将yuv数据copy到图形缓冲区

         memcpy(dst, data, dst_y_size);//将yuv数据copy到图形缓冲区

        for(size_t i =0;i<dst_c_size; i++) {

            *((char *)dst +dst_y_size +i*2 +1) = *(((char *)data +dst_y_size +i));                

            *((char *)dst +dst_y_size +i*2 ) = *(((char *)data +dst_y_size +dst_c_size +i));

        }

     }

    CHECK_EQ(0, mapper.unlock(buf->handle));

    if ((err = mNativeWindow->queueBuffer(mNativeWindow.get(), buf,

            -1)) != 0) {

        ALOGW("Surface::queueBuffer returned error %d", err);

    }

    buf = NULL;

    return NO_ERROR;

}