IDirect3DViewport::QueryInterface

HRESULT QueryInterface(REFIID riid, LPVOID* ppvObj);

Determines if the Direct3DViewport object supports a particular COM interface. If it does, the system increases the reference count for the object, and the application can begin using that interface immediately. This method is part of the IUnknown interface inherited by Direct3DViewport.

·Returns D3D_OK if successful, or an error otherwise, which may be one of the following values:

DDERR_INVALIDOBJECT

DDERR_INVALIDPARAMS

riid

Reference identifier of the interface being requested.

ppvObj

Address of a pointer that will be filled with the interface pointer if the query is successful.

If the application does not need to use the interface retrieved by a call to this method, it must call the Release method for that interface to free it. The IDirect3DViewport::QueryInterface method allows Direct3DViewport objects to be extended by Microsoft and third parties without interfering with each other's existing or future functionality.