Blobby! - Shape/Blob Recognition Code

/// \file CVDShowUtil.cpp
/// \brief DirectShow utility functions straight out of the DirectX 9.0 documentation.
#include "CVDShowUtil.h"

// GetUnconnectedPin
//    Finds an unconnected pin on a filter in the desired direction
HRESULT 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;
}

// Disconnect any connections to the filter.
HRESULT DisconnectPins(IBaseFilter *pFilter)
{
    IEnumPins *pEnum = 0;
    IPin *pPin = 0;
    HRESULT hr = pFilter->EnumPins(&pEnum);
    if (FAILED(hr))
    {
        return hr;
    }
    
    while (pEnum->Next(1, &pPin, NULL) == S_OK)
    {
      pPin->Disconnect();
      pPin->Release();
    }
    pEnum->Release();
    
    // Did not find a matching pin.
    return S_OK;
}

// ConnectFilters
//    Connects a pin of an upstream filter to the pDest downstream filter
HRESULT 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;
}



// ConnectFilters
//    Connects two filters
HRESULT 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;
}

// LocalFreeMediaType
//    Free the format buffer in the media type
void LocalFreeMediaType(AM_MEDIA_TYPE& mt)
{
    if (mt.cbFormat != 0)
    {
        CoTaskMemFree((PVOID)mt.pbFormat);
        mt.cbFormat = 0;
        mt.pbFormat = NULL;
    }
    if (mt.pUnk != NULL)
    {
        // Unecessary because pUnk should not be used, but safest.
        mt.pUnk->Release();
        mt.pUnk = NULL;
    }
}

// LocalDeleteMediaType
//    Free the format buffer in the media type, 
//    then delete the MediaType ptr itself
void LocalDeleteMediaType(AM_MEDIA_TYPE *pmt)
{
    if (pmt != NULL)
    {
        LocalFreeMediaType(*pmt); // See FreeMediaType for the implementation.
        CoTaskMemFree(pmt);
    }
}