怎樣給filter加入自己定義接口及調用

本樣例是在VirtualCamera的基礎上加入的自己定義接口用來實作exe控制osd的顯示。

1. 接口部分

#ifndef __H_MyFilter__ #define __H_MyFilter__ #ifdef __cplusplus extern "C" { #endif //#include <initguid.h> //EXTERN_GUID EXTERN_GUID(IID_IMyFilter,   0xef31f705, 0x32a7, 0x477a, 0x90, 0xc9, 0x2c, 0x7e, 0x81, 0xeb, 0x2, 0x5d); DECLARE_INTERFACE_(IMyFilter,IUnknown) { STDMETHOD(setOSD) (THIS_ int osd_en) PURE; }; } #endif  

2.filter繼承接口

#include "myfilter.h"

class CVCam : public CSource ,public IMyFilter

public:

    static CUnknown * WINAPI CreateInstance(LPUNKNOWN lpunk, HRESULT *phr); 

STDMETHODIMP NonDelegatingQueryInterface(REFIID riid, void **ppv);//????

DECLARE_IUNKNOWN;

STDMETHODIMP  setOSD(int osd_en);

    IFilterGraph *GetGraph() {return m_pGraph;}

    int osd_enable;

private:

    CVCam(LPUNKNOWN lpunk, HRESULT *phr);

CVCamPin *m_pPin;

/////////////////////////////////////

STDMETHODIMP  CVCam::setOSD(int osd_en)

osd_enable = osd_en;

return S_OK;

STDMETHODIMP CVCam::NonDelegatingQueryInterface(REFIID riid, void **ppv)

if(riid == _uuidof(IAMStreamConfig) || riid == _uuidof(IKsPropertySet))

// m_paStreams[0]->QueryInterface(riid, ppv);

return m_paStreams[0]->QueryInterface(riid, ppv);

else if (riid == IID_IMyFilter)

return GetInterface((IMyFilter *) this, ppv);

else

return CBaseFilter::NonDelegatingQueryInterface(riid, ppv);//改動

3.應用程式調用

        //依據guid 查找filter

  hr = CoCreateInstance(CLSID_myFilter, 0, CLSCTX_INPROC_SERVER, IID_IBaseFilter, reinterpret_cast<void**>(&pSrcFilter));  

         IMyFilter *pInterface = NULL; 

         hr = pSrcFilter->QueryInterface(IID_IMyFilter, (void **)&pInterface);//從filter上查詢接口

        pInterface->setOSD(0);//使用接口函數

<b>本文轉自mfrbuaa部落格園部落格，原文連結：</b><b>http://www.cnblogs.com/mfrbuaa/p/5308098.html</b><b>，如需轉載請自行聯系原作者</b>