VK_NV_external_memory
Other Extension Metadata
Last Modified Date
2016-08-19
IP Status
No known IP claims.
Contributors
- James Jones, NVIDIA
- Carsten Rohde, NVIDIA
Description
Applications may wish to export memory to other Vulkan instances or other APIs, or import memory from other Vulkan instances or other APIs to enable Vulkan workloads to be split up across application module, process, or API boundaries. This extension enables applications to create exportable Vulkan memory objects such that the underlying resources can be referenced outside the Vulkan instance that created them.
New Structures
- Extending VkImageCreateInfo:
- Extending VkMemoryAllocateInfo:
New Enum Constants
VK_NV_EXTERNAL_MEMORY_EXTENSION_NAME
VK_NV_EXTERNAL_MEMORY_SPEC_VERSION
- Extending VkStructureType:
VK_STRUCTURE_TYPE_EXPORT_MEMORY_ALLOCATE_INFO_NV
VK_STRUCTURE_TYPE_EXTERNAL_MEMORY_IMAGE_CREATE_INFO_NV
Issues
1) If memory objects are shared between processes and APIs, is this considered aliasing according to the rules outlined in the Memory Aliasing section?
RESOLVED: Yes, but strict exceptions to the rules are added to allow some forms of aliasing in these cases. Further, other extensions may build upon these new aliasing rules to define specific support usage within Vulkan for imported native memory objects, or memory objects from other APIs.
2) Are new image layouts or metadata required to specify image layouts and layout transitions compatible with non-Vulkan APIs, or with other instances of the same Vulkan driver?
RESOLVED: No.
Separate instances of the same Vulkan driver running on the same GPU should
have identical internal layout semantics, so applications have the tools
they need to ensure views of images are consistent between the two
instances.
Other APIs will fall into two categories: Those that are Vulkan compatible
(a term to be defined by subsequent interopability extensions), or Vulkan
incompatible.
When sharing images with Vulkan incompatible APIs, the Vulkan image must be
transitioned to the VK_IMAGE_LAYOUT_GENERAL
layout before handing it
off to the external API.
Note this does not attempt to address cross-device transitions, nor transitions to engines on the same device which are not visible within the Vulkan API. Both of these are beyond the scope of this extension.
Examples
// TODO: Write some sample code here.
Version History
- Revision 1, 2016-08-19 (James Jones)
- Initial draft