There was a nasty issue when moving the Device -- because the Queue
instances are populated with the Device pointer in the constructor,
moving the Device makes the Queue device pointer invalid and those
instances are useless. Discovered this when using VulkanTester to test
an upcoming Queue::submit() -- until then, the Device pointer in the
Queue wasn't really used for anything and so this wasn't known.
Making the Device immovable is thus the only sane way to keep the
current Queue retrieval workflow, which I'd say is much cleaner than
having to manually query the device for queues later using some
error-prone indices and whatnot. On the other hand, this finally makes
it possible to have a failable device creation, instead of the device
creation failing on an assert (or failing silently when
CORRADE_NO_ASSERT is defined). This is consistent with how the GL
wrapper works.
Also, because all device-dependent objects need to keep a pointer to the
originating Device in order to access Vulkan function pointers, having
it immovable makes it considerably faster. I'll make Instance immovable
with tryCreate() next because it seems like a good thing to do there as
well.
After I implemented the render pass wrapper, seeing how the
RenderPassCreateInfo structure and its dependencies were HUGE compared
to the actual tiny and lean RenderPass, I felt uneasy dragging their
definition along to every place where a RenderPass gets used. It's not
as bad with the others, but as new extensions are implemented I expect
that to get the same.
This change makes it easier for me to accept that Image.h / Buffer.h
depends on Memory.h. There isn't a real measurable difference when
building Magnum itself (50 ms out of 7 seconds for the Vk library
alone), but that's because most of the code (and tests) needs the
CreateInfo structures anyway.
Vladimír Vondruš