DirextX编程

开发平台：
Visual C++

BuildGraph.cpp：源码内容
							#include "StdAfx.h"
#include "BuildGraph.h"
CBuildGraph::CBuildGraph(void)
:pGraph(NULL)
,pGrabber(NULL)
,pControl(NULL)
,pEvent(NULL)
,pF(NULL)
,pNull(NULL)
,cbBuffer(0)
{
}
CBuildGraph::~CBuildGraph(void)
{
	if(pControl)
		pControl->Stop();
	if(pGraph)
		pGraph->Release();
	if(pGrabber)
		pGrabber->Release();
	if(pControl)
		pControl->Release();
	if(pEvent)
		pEvent->Release();
	if(pF)
		pF->Release();
	if(pNull)
		pNull->Release();
}
HRESULT CBuildGraph::GetUnconnectedPin(
    IBaseFilter *pFilter,   // Pointer to the filter.
    PIN_DIRECTION PinDir,   // Direction of the pin to find.
    IPin **ppPin)           // Receives a pointer to the pin.
{
    *ppPin = 0;
    IEnumPins *pEnum = 0;
    IPin *pPin = 0;
    HRESULT hr = pFilter->EnumPins(&pEnum);
    if (FAILED(hr))
    {
        return hr;
    }
    while (pEnum->Next(1, &pPin, NULL) == S_OK)
    {
        PIN_DIRECTION ThisPinDir;
        pPin->QueryDirection(&ThisPinDir);
        if (ThisPinDir == PinDir)
        {
            IPin *pTmp = 0;
            hr = pPin->ConnectedTo(&pTmp);
            if (SUCCEEDED(hr))  // Already connected, not the pin we want.
            {
                pTmp->Release();
            }
            else  // Unconnected, this is the pin we want.
            {
                pEnum->Release();
                *ppPin = pPin;
                return S_OK;
            }
        }
        pPin->Release();
    }
    pEnum->Release();
    // Did not find a matching pin.
    return E_FAIL;
}
HRESULT CBuildGraph::GetCapturePin(
		IBaseFilter *pFilter,   // Pointer to the filter.
		PIN_DIRECTION PinDir,   // Direction of the pin to find.
		IPin **ppPin)           // Receives a pointer to the pin.
{
    *ppPin = 0;
    IEnumPins *pEnum = 0;
    IPin *pPin = 0;
    HRESULT hr = pFilter->EnumPins(&pEnum);
    if (FAILED(hr))
    {
        return hr;
    }
    while (pEnum->Next(1, &pPin, NULL) == S_OK)
    {
        PIN_DIRECTION ThisPinDir;
        pPin->QueryDirection(&ThisPinDir);
        if (ThisPinDir == PinDir)
        {
            IPin *pTmp = 0;
            hr = pPin->ConnectedTo(&pTmp);
            if (SUCCEEDED(hr))  // Already connected, not the pin we want.
            {
                pTmp->Release();
            }
			else  // Unconnected, this is the pin we want.
			{
				pEnum->Release();
				GUID TempGuid;
				hr = GetPinCategory(pPin,&TempGuid);
				if(hr == S_OK)
				{
					if(TempGuid == PIN_CATEGORY_CAPTURE)
					{
						*ppPin = pPin;
						return S_OK;
					}
				}
			}
		}
        pPin->Release();
    }
    pEnum->Release();
    // Did not find a matching pin.
    return E_FAIL;
}
HRESULT CBuildGraph::ConnectFilters(
    IGraphBuilder *pGraph, // Filter Graph Manager.
    IPin *pOut,            // Output pin on the upstream filter.
    IBaseFilter *pDest)    // Downstream filter.
{
    if ((pGraph == NULL) || (pOut == NULL) || (pDest == NULL))
    {
        return E_POINTER;
    }
#ifdef debug
        PIN_DIRECTION PinDir;
        pOut->QueryDirection(&PinDir);
        _ASSERTE(PinDir == PINDIR_OUTPUT);
#endif
    // Find an input pin on the downstream filter.
    IPin *pIn = 0;
    HRESULT hr = GetUnconnectedPin(pDest, PINDIR_INPUT, &pIn);
    if (FAILED(hr))
    {
        return hr;
    }
    // Try to connect them.
    hr = pGraph->Connect(pOut, pIn);
    pIn->Release();
    return hr;
}
HRESULT CBuildGraph::ConnectFilters(
    IGraphBuilder *pGraph, 
    IBaseFilter *pSrc, 
    IBaseFilter *pDest)
{
    if ((pGraph == NULL) || (pSrc == NULL) || (pDest == NULL))
    {
        return E_POINTER;
    }
    // Find an output pin on the first filter.
    IPin *pOut = 0;
    HRESULT hr = GetUnconnectedPin(pSrc, PINDIR_OUTPUT, &pOut);
    if (FAILED(hr)) 
    {
        return hr;
    }
    hr = ConnectFilters(pGraph, pOut, pDest);
    pOut->Release();
    return hr;
}
HRESULT CBuildGraph::ConnectCaptureFilters(
    IGraphBuilder *pGraph, 
    IBaseFilter *pSrc, 
    IBaseFilter *pDest)
{
    if ((pGraph == NULL) || (pSrc == NULL) || (pDest == NULL))
    {
        return E_POINTER;
    }
    // Find an output pin on the first filter.
    IPin *pOut = 0;
    HRESULT hr = GetCapturePin(pSrc, PINDIR_OUTPUT, &pOut);
    if (FAILED(hr)) 
    {
        return hr;
    }
    hr = ConnectFilters(pGraph, pOut, pDest);
    pOut->Release();
    return hr;
}
HRESULT CBuildGraph::GetPinCategory(IPin *pPin, GUID *pPinCategory)
{
    HRESULT hr;
    IKsPropertySet *pKs;
    hr = pPin->QueryInterface(IID_IKsPropertySet, (void **)&pKs);
    if (FAILED(hr))
    {
        // The pin does not support IKsPropertySet.
        return hr;
    }
    // Try to retrieve the pin category.
    DWORD cbReturned;
    hr = pKs->Get(AMPROPSETID_Pin, AMPROPERTY_PIN_CATEGORY, NULL, 0, 
        pPinCategory, sizeof(GUID), &cbReturned);
    // If this succeeded, pPinCategory now contains the category GUID.
    pKs->Release();
    return hr;
}
HRESULT CBuildGraph::InitCaptureVideo(IBaseFilter *pSrc)
{
	HRESULT hr;
	hr = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC,IID_IGraphBuilder, (void **) &pGraph);
	hr = CoCreateInstance(CLSID_SampleGrabber, NULL, CLSCTX_INPROC_SERVER,
		IID_IBaseFilter, (void **)&pF);
	hr = CoCreateInstance(CLSID_NullRenderer, NULL, CLSCTX_INPROC_SERVER,
		IID_IBaseFilter, reinterpret_cast<void**>(&pNull));
	hr = pF->QueryInterface(IID_ISampleGrabber,(void **)&pGrabber);
	hr = pGraph->QueryInterface(IID_IMediaControl,(LPVOID *)&pControl);
	hr = pGraph->QueryInterface(IID_IMediaEvent,(LPVOID *)&pEvent);
	hr = pGraph->AddFilter(pF, L"SampleGrabber");
	hr = pGraph->AddFilter(pSrc, L"Video Capture");
	hr = pGraph->AddFilter(pNull, L"NullRenderer");
	AM_MEDIA_TYPE  pmt;
	ZeroMemory(&pmt, sizeof(AM_MEDIA_TYPE));
	pmt.majortype = MEDIATYPE_Video;
	pmt.subtype = MEDIASUBTYPE_RGB24;
	hr = pGrabber->SetMediaType(&pmt);
	hr = ConnectCaptureFilters(pGraph,pSrc, pF);
	hr = ConnectFilters(pGraph, pF, pNull);
	pControl->Run();
	hr = pGrabber->SetOneShot(TRUE);
	hr = pGrabber->SetBufferSamples(TRUE);
	long evCode;
	hr = pEvent->WaitForCompletion(INFINITE, &evCode); // Wait till it's done.
	hr = pGrabber->GetCurrentBuffer(&cbBuffer, NULL);
	hr = pGrabber->SetOneShot(FALSE);
	OAFilterState pfs;
	hr = pControl->Stop();
	hr = pControl->GetState(INFINITE, &pfs);
	hr = pControl->Run();
	hr = pControl->GetState(INFINITE, &pfs);
	if(pfs == State_Running&&hr == S_OK)
	{
         hr = S_OK;
	}
	else
	{
         hr = E_FAIL;
	}
	return hr;
}

						