Camera2 Preview流程

CameraDevice createCaptureSession

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Surface Consumer/Hal Producter

注意下面方法的注释，processCaptureResult这个方法就是hal到时候回调图像数据的地方

• framworks

    /**
     *
     * Camera HAL device callback methods
     */

    void Camera3Device::processCaptureResult(const camera3_capture_result *result)

• hal 返回数据

  void ResultProcessor::returnPendingBuffers(RequestState_t * reqState)
    {
        unsigned int i;
        camera3_capture_result_t result;
        camera3_stream_buffer_t buf;
        std::shared_ptr<CameraBuffer> pendingBuf;
        Camera3Request *request = reqState->request;

        /**
         * protection against duplicated calls when all buffers have been returned
         */
        if (reqState->buffersReturned == reqState->buffersToReturn)
        {
            LOGW("trying to return buffers twice. Check PSL implementation");
            return;
        }

        for (i = 0; i < reqState->pendingBuffers.size(); i++)
        {
            CLEAR(buf);
            CLEAR(result);

            pendingBuf = reqState->pendingBuffers[i];
            if (!request->isInputBuffer(pendingBuf))
            {
                result.num_output_buffers = 1;
            }
            result.frame_number = reqState->reqId;
            // Force drop buffers when request error
            buf.status = request->getError() ? CAMERA3_BUFFER_STATUS_ERROR : pendingBuf->status();
            buf.stream = pendingBuf->getOwner()->getStream();
            /* framework check the handle point other than handle */
            /* buf.buffer = pendingBuf->getBufferHandle(); */
            buf.buffer = pendingBuf->getBufferHandlePtr();
            pendingBuf->getFence(&buf);
            result.result = nullptr;
            if (request->isInputBuffer(pendingBuf))
            {
                result.input_buffer = &buf;
                LOGD(" <Request %d> return an input buffer", reqState->reqId);
            }
            else
            {
                result.output_buffers = &buf;
            }

            processCaptureResult(reqState, &result);//回调数据
            pendingBuf->getOwner()->decOutBuffersInHal();
            reqState->buffersReturned += 1;
            LOGD(" <Request %d> camera id %d buffer done %d/%d ", reqState->reqId,
                 reqState->request->getCameraId(), reqState->buffersReturned, reqState->buffersToReturn);
        }

        reqState->pendingBuffers.clear();
    }

    void ResultProcessor::processCaptureResult(RequestState_t * reqState, camera3_capture_result * result)
    {
        int numMetaLeft = mPartialResultCount - reqState->partialResultReturned;
        int numBufLeft = reqState->buffersToReturn - reqState->buffersReturned;

        // Report request error when it's the last result
        if (numMetaLeft + numBufLeft == 1)
        {
            Camera3Request *request = reqState->request;
            if (request->getError())
                returnRequestError(request->getId());
        }

        mCallbackOps->process_capture_result(mCallbackOps, result); // callback to framworks
    }

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Camera3Stream类图

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Surface和SurfaceFlinger

Surface创建

注意：Native层的Surface和Java层的Surface有所区别：
1. Native Surface和ANativeWindow强绑定
2. Java Surface 是对包含handle和gbp引用的SurfaceControl的引用的封装

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Surface和ANativeWindow

追踪Surface创建过程主要是为了搞清Surface和ANativeWindow的关系

• Surface.cpp

    Surface::Surface(const sp<IGraphicBufferProducer> &bufferProducer, bool controlledByApp)
        : mGraphicBufferProducer(bufferProducer),
          mCrop(Rect::EMPTY_RECT),
          mBufferAge(0),
          mGenerationNumber(0),
          mSharedBufferMode(false),
          mAutoRefresh(false),
          mSharedBufferSlot(BufferItem::INVALID_BUFFER_SLOT),
          mSharedBufferHasBeenQueued(false),
          mQueriedSupportedTimestamps(false),
          mFrameTimestampsSupportsPresent(false),
          mEnableFrameTimestamps(false),
          mFrameEventHistory(std::make_unique<ProducerFrameEventHistory>())
    {
        // Initialize the ANativeWindow function pointers.
        ANativeWindow::setSwapInterval = hook_setSwapInterval;
        ANativeWindow::dequeueBuffer = hook_dequeueBuffer; // gmq 这
        ANativeWindow::cancelBuffer = hook_cancelBuffer;
        ANativeWindow::queueBuffer = hook_queueBuffer;
        ANativeWindow::query = hook_query;
        ANativeWindow::perform = hook_perform;

        ANativeWindow::dequeueBuffer_DEPRECATED = hook_dequeueBuffer_DEPRECATED;
        ANativeWindow::cancelBuffer_DEPRECATED = hook_cancelBuffer_DEPRECATED;
        ANativeWindow::lockBuffer_DEPRECATED = hook_lockBuffer_DEPRECATED;
        ANativeWindow::queueBuffer_DEPRECATED = hook_queueBuffer_DEPRECATED;
        ....
    }

Surface Producter/SurfaceFlinger Consumer

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框架流程汇总

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