EXT_external_objects and EXT_external_objects_fd are groups
of extensions that allow OpenGL
and Vulkan to access to the same resources.
I've contributed to this extension implementation for iris
(implemented EXT_semaphore and fixed the implementation of
EXT_memory_object), radeonsi (added support for buffers in
EXT_memory_object), i965 (reviewed the implementation).
As there were no conformance tests for them or examples,
I've written a small Vulkan rendering framework inside Piglit
(OpenGL driver testing framework) and tests that check
various extension use cases.
I've also written a series of blog posts/mini-tutorials
about the use of these extensions: