Cannot use memory auto-export + import at the same time

[maxime-modulopi]

VMA version: 3442720

What i'm trying to do is to have all VMA-allocated GPU images/buffers be exportable by default while also supporting memory import (auto-export and import are mutually exclusive here).

For the auto-export part, I set the supported handle types in VmaAllocatorCreateInfo::pTypeExternalMemoryHandleTypes for all DEVICE_LOCAL memory types.

For the import part, I use vmaCreateDedicatedImage/vmaCreateDedicatedBuffer + VkImportMemoryWin32HandleInfoKHR + custom pool, since the doc says that VmaAllocatorCreateInfo::pTypeExternalMemoryHandleTypes only affects default pools.

The problem I'm facing is that when I import memory, VkExportMemoryAllocateInfoKHR from the auto-export part still gets pushed to the VkMemoryAllocateInfo pNext chain, which means I end up with both VkExportMemoryAllocateInfoKHR with export handle type + VkImportMemoryWin32HandleInfoKHR with import handle type.

As the handle types I use for auto-export and import are not compatible with each other (D3D11_TEXTURE for import and OPAQUE_WIN32 for export), this doesn't work.

[sawickiap]

It is not true that VmaAllocatorCreateInfo::pTypeExternalMemoryHandleTypes affects only default pools and documentation doesn't state that. It affects all memory allocated using VMA from a particular memory type index.

If you need some of the allocations from a certain memory type to not have VkExportMemoryAllocateInfoKHR attached, you need to either:

• Not use the global VmaAllocatorCreateInfo::pTypeExternalMemoryHandleTypes, but create custom pools or dedicated allocations when you need to export.
• Or allocate imported memory using raw Vulkan functions, outside of VMA.