c++ - DX11 Mapping vertex buffer as WRL::ComPtr -

i'm having trouble mapping vertex buffer. when so:

id3d11buffer* pd3dsinglevertexbuffer; ... pd3dimmediatecontext->map(pd3dsinglevertexbuffer, null, d3d11_map_write_discard, null, &mappedsubresource); 

everything works, frames works properly. however, when things that:

microsoft::wrl::comptr<id3d11buffer> pd3dsinglevertexbuffer; ... pd3dimmediatecontext->map(pd3dsinglevertexbuffer.get(), null, d3d11_map_write_discard, null, &mappedsubresource); 

nothing gets rendered, application doesn't crash, nor there errors.

do know doing wrong?

as discovered, while classic approach creating single-element arrays used in d3d use address-of operator on single element, it's commonly used pass output paramaters creation methods (e.g. createdevice(&device)). since more common usage, in context of entire win32 api surface, comptr designed safely provide output-parameter semantics, release()ing contained object prior returning address.

there 2 ways around problem. first create array of objects, e.g. id3d11buffer** ppbuffers[] = { pbuffer.get() };. second utilize comptr::getaddressof returns address of contained object without changing refcount. in latter case, careful not use in cases using container output parameter, otherwise you'll leak held object.