Graphic学习笔记-创新互联

发现一个比较好的介绍graphic帖子， 后面会跟着帖子来梳理下graphic相关知识点
http://blog.csdn.net/u014409795/article/details/51276468

创新互联公司是一家专业提供青秀企业网站建设,专注与成都网站设计、成都做网站、H5技术、小程序制作等业务。10年已为青秀众多企业、政府机构等服务。创新互联专业的建站公司优惠进行中。

1. BufferQueue

      class BufferQueue {
             class ProxyConsumerListener : public BnConsumerListener;
             static void createBufferQueue(sp* outProducer,
                       sp* outConsumer,
                        const sp& allocator = NULL);
        private:
            BufferQueue(); // Create through createBufferQueue

    }

    //看起来只有consumer一个角色？

   void BufferQueue::createBufferQueue(sp* outProducer,
       sp* outConsumer,
       const sp& allocator) {

       sp core(new BufferQueueCore(allocator));
       sp producer(new BufferQueueProducer(core));

       sp consumer(new BufferQueueConsumer(core));

 BufferQueue核心是BufferQueueCore,

  看BufferQueueCore里面是管理什么的

 class BufferQueueCore : public virtual RefBase {

          friend class BufferQueueProducer;
          friend class BufferQueueConsumer;

          typedef Vector Fifo; //一个BufferItem Vector

        private:

        // mAllocator is the connection to SurfaceFlinger that is used to allocate
        // new GraphicBuffer objects.
       sp mAllocator;
        // mSlots is an array of buffer slots that must be mirrored on the producer
       // side. This allows buffer ownership to be transferred between the producer
       // and consumer without sending a GraphicBuffer over Binder. The entire
      // array is initialized to NULL at construction time, and buffers are
      // allocated for a slot when requestBuffer is called with that slot's index.
       BufferQueueDefs::SlotsType mSlots;  //

       BufferSlot()
   : mEglDisplay(EGL_NO_DISPLAY),
     mBufferState(BufferSlot::FREE),   //state
     mRequestBufferCalled(false),
     mFrameNumber(0),
     mEglFence(EGL_NO_SYNC_KHR),
     mAcquireCalled(false),
     mNeedsCleanupOnRelease(false),
     mAttachedByConsumer(false) {
   }

   // mGraphicBuffer points to the buffer allocated for this slot or is NULL
   // if no buffer has been allocated.
   sp mGraphicBuffer;  //bufferslot中指向GraphicBuffer

   enum BufferState { // state 表示buffer state

    FREE = 0,  //FREE indicates that the buffer is available to be dequeued by the producer.
     // 允许produce获取该buffer，填充数据，状态变为dequeue   free 时表示该buffer还被bufferqueue 所有

  DEQUEUED = 1,// DEQUEUED indicates that the buffer has been dequeued by the  producer, but has not yet been queued or canceled. The slot is "owned" by the producer. 处于待填充数据状态,被producer所有

 QUEUED = 2,//QUEUED indicates that the buffer has been filled by the producer and queued for use by the consumer; producer填充完数据，准备提供给consumer消费，被bufferqueue所有

  ACQUIRED = 3//ACQUIRED indicates that the buffer has been acquired by the  consumer.

  buffer被consumer获取到，消费完后转为free

  在bufferqueuecore中bufferItem又是什么
  class BufferItem : public Flattenable {

  // mGraphicBuffer points to the buffer allocated for this slot, or is NULL
   // if the buffer in this slot has been acquired in the past (see
   // BufferSlot.mAcquireCalled).
   sp mGraphicBuffer; //也有GraphicBuffer指针

    union {
       // mSlot is the slot index of this buffer (default INVALID_BUFFER_SLOT).
       int mSlot; // slot数组中索引

       // mBuf is the former name for mSlot
       int mBuf; // 旧名字
   };

  BufferSlot 与 BufferItem 都指向GraphicBuffer,然后又 通过mSlot下标关联起来，至于两者使用场景再看

另外有需要云服务器可以了解下创新互联scvps.cn，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。

网页名称：Graphic学习笔记-创新互联
分享地址：http://bzwzjz.com/article/ccidoo.html