Retrieves an application-specific DWORD of data.
HRESULT retVal = object.GetAppData(pdwAppData);
Pointer to a DWORD of data that was set with the IDXSurface::SetAppData method. If no call has been made to IDXSurface::SetAppData, the value returned is 0.
This method retrieves a tag set by an application for a DXSurface. For example, applications that use 2-D transforms can use this method to retrieve a tag from a transform input surface. This enables the application to identify which surfaces were hit when doing 2-D hit testing. However, applications can use this data in any way that is useful.
All surface implementations must support IDXSurface::SetAppData and IDXSurface::GetAppData.