Vulkan Buffer Win32 Handle export

Hello NVIDIA forums,

I have come across weird behaviour trying to reproduce OptiX denoiser integration as demonstrated in vk_denoise sample nvpro-samples/vk_denoise (on github. Can only link once so this is not a link)

My code can be found in foray-denoiser-optix/foray_optix_cudabuffer.cpp at main · Vulkemp/foray-denoiser-optix · GitHub
For a full testing setup, clone github/Vulkemp/foray-denoising recursively, set ENABLE_OPTIX in CMake cache, set OPTIX_INCLUDE to OptiX include directory. After launch switch denoiser in ImGui to OptiX.

Description of the problem:

  • vkGetMemoryWin32HandleKHR returns VK_SUCCESS, but referenced handle is set to all zeroes and is not a valid handle.


  • Vulkan 1.3
  • Enabled Instance Extensions: VK_KHR_EXTERNAL_MEMORY_CAPABILITIES

Buffer Allocation

  • bufferCreateInfo.pNext initialized with VkExternalMemoryBufferCreateInfo object
  • Memory allocated device local and in dedicated device memory
  • Allocation via Vulkan Memory Allocator


  • Windows 10 21H2
  • GTX 1070ti, Driver 522.25
  • Vulkan SDK 1.3.224
  • OptiX v7.5.0


  • The same code (with the relevant extensions and flags set to the FD handle equivalent) runs fine on linux on the same machine (driver 515)
  • nvpro/vk_denoise runs fine on my machine (but I had to disable parts of the render pipeline, due to my GPU not supporting Ray Query Extension, so I cannot be sure it works 100%)
  • nvpro/vk_denoise invokes the same function pointer for vkGetMemoryWin32HandleKHR (I made sure that the Dispatch Table has the correct function pointer)

Attempts to fix the issue:

  • Enable a bunch of unnecessary but perhaps related vulkan extensions
  • Step through vk_denoise Buffer setup and my code in unison to make sure the buffer is configured the same