Sets the surface's application-specified DWORD of data.
HRESULT retVal = object.SetAppData(dwAppData);
Any DWORD value to be used by the application to store information specific to the surface.
This method enables an application to tag a surface with a unique DWORD of data. For example, applications that use 2-D transforms can use this method to tag input surfaces to the transforms. 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.
The IDXSurfaceFactory::CreateD3DRMTexture method copies the application data to the texture from the DXSurface when it creates the texture.
All surface implementations must support IDXSurface::SetAppData and IDXSurface::GetAppData.