Share direct3d11 rendered frame from swapchain backbuffer as texture with another separate process

Question

So I will elaborate on the title

What I am trying to accomplish is do all the computation and rendering in one process and then read the resulting frame (I am going for swapchain backbuffer before present when all computation is done) from another process and show it on display. Basically I want to share video memory (not the whole screen just the app window) between two separate processes.

I am using direct3d11 with DirectXTK. My laptop has NVIDIA gpu along with intel UHD 620 graphics . Opened visual studio with admin access.

Here goes the code where I try to create shared handle to the buffer

    auto swapChain = m_deviceResources->GetSwapChain();

    /*ComPtr< ID3D11Resource> backbuffer;*/
    /*swapChain->GetBuffer(0, __uuidof(ID3D11Resource),
    (void **) backbuffer.GetAddressOf());*/

    swapChain->GetBuffer(0, __uuidof(ID3D11Texture2D),(void **)tex_shared.GetAddressOf());

    D3D11_TEXTURE2D_DESC tex_2d_desc{};
    tex_shared->GetDesc(&tex_2d_desc);
    tex_2d_desc.MiscFlags = D3D11_RESOURCE_MISC_SHARED_KEYEDMUTEX | D3D11_RESOURCE_MISC_SHARED_NTHANDLE;
    tex_2d_desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ | D3D11_CPU_ACCESS_WRITE;

    HANDLE sharedhandle=nullptr;
    IDXGIResource1* pOtherResource=nullptr;
    tex_shared->QueryInterface(__uuidof(IDXGIResource1), (void**)&pOtherResource);

    SECURITY_ATTRIBUTES sa{};
    sa.bInheritHandle = FALSE;
    sa.nLength = sizeof(SECURITY_ATTRIBUTES);
    sa.lpSecurityDescriptor = NULL;

    pOtherResource->CreateSharedHandle(&sa,GENERIC_ALL,L"SharedTexture" ,&sharedhandle);

From another process I try to retrieve the handle with this code

  ComPtr<IDXGIResource1> p_tex_shared;
  device->OpenSharedResourceByName(L"SharedTexture", 
    DXGI_SHARED_RESOURCE_READ ,
    __uuidof(IDXGIResource1), 
    (void**)p_tex_shared.GetAddressOf());

But I get this error

Exception thrown at 0x00007FF84751466C in SimpleTrianglePC.exe: Microsoft C++ exception: _com_error at memory location 0x000000139CEFF248.
D3D11 ERROR: ID3D11Device::OpenSharedResourceByName: Returning E_INVALIDARG, meaning 
invalid parameters were passed. [ STATE_CREATION ERROR #381: 
DEVICE_OPEN_SHARED_RESOURCE_INVALIDARG_RETURN]
D3D11: **BREAK** enabled for the previous message, which was: [ ERROR STATE_CREATION 
Exception thrown at 0x00007FF84751466C (KernelBase.dll) in SimpleTrianglePC.exe: 
0x0000087A (parameters: 0x0000000000000001, 0x000000139CEFC500, 0x000000139CEFE2D0).
Unhandled exception at 0x00007FF84751466C (KernelBase.dll) in SimpleTrianglePC.exe: 
0x0000087A (parameters: 0x0000000000000001, 0x000000139CEFC500, 0x000000139CEFE2D0).

I tried using OpenSharedResource1 too instead of OpenSharedResourceByName but gives same error.

Answer 1

You can't modify the texture surface owned by the DXGI swapchain to add the share flags like you tried to do above. Your best bet is going to require copying the backbuffer to a sharable texture.

1. Create a sharable texture using the same size and format as the swapchain backbuffer.
2. Obtain the DXGI backbuffer texture
3. Use ID3D11DeviceContext::CopyResource to copy the context from the backbuffer to the sharable texture each frame.

See Microsoft Docs