There was still a code path that could wait on a timeline semaphore tick
that would never be signalled.
While we are at it, make use of more STL algorithms.
Avoids waiting idle while the GPU finishes to do work, and fixes an
issue where we'd wait forever if a single command buffer (logic tick)
all the data.
Ports from OpenGL the optimization to skip small 3D uniform buffer
uploads. This will take advantage of the previously introduced stream
buffer.
Fixes instances where the staging buffer offset was being ignored.
This uses a ring buffer similar to OpenGL's stream buffer for small
uploads. This stops us from allocating several small buffers, reducing
memory fragmentation and cache locality.
It uses dedicated allocations when possible.
Allow users of the allocator to hint memory usage for downloads. This
removes the non-descriptive boolean passed for "host visible" or not
host visible memory commits, and uses an enum to hint device local,
upload and download usages.
Fix a bug where the memory allocator could leave gaps between commits.
To fix this the allocation algorithm was reworked, although it's still
short in number of lines of code.
Rework the allocation API to self-contained movable objects instead of
naively using an unique_ptr to do the job for us. Remove the VK prefix.
The "VK" prefix predates the "Vulkan" namespace. It was carried around
the codebase for consistency. "VKDevice" currently is a bad alias with
"VkDevice" (only an upcase character of difference) that can cause
confusion. Rename all instances of it.
This reworks how host<->device synchronization works on the Vulkan
backend. Instead of "protecting" resources with a fence and signalling
these as free when the fence is known to be signalled by the host GPU,
use timeline semaphores.
Vulkan timeline semaphores allow use to work on a subset of D3D12
fences. As far as we are concerned, timeline semaphores are a value set
by the host or the device that can be waited by either of them.
Taking advantange of this, we can have a monolithically increasing
atomic value for each submission to the graphics queue. Instead of
protecting resources with a fence, we simply store the current logical
tick (the atomic value stored in CPU memory). When we want to know if a
resource is free, it can be compared to the current GPU tick.
This greatly simplifies resource management code and the free status of
resources should have less false negatives.
To workaround bugs in validation layers, when these are attached there's
a thread waiting for timeline semaphores.
All drivers (even Intel) seem to have a device local memory type that is
not host visible. Remove this flag so all devices follow the same path.
This fixes a crash when trying to map to host device local memory on
integrated devices.
Introduce a default buffer getter that lazily constructs an empty
buffer. This is intended to match OpenGL's buffer 0.
Use this for disabled vertex and uniform buffers.
While we are at it, include vertex buffer usages for staging buffers to
silence validation errors.
The job of this abstraction is to provide staging buffers for temporary
operations. Think of image uploads or buffer uploads to device memory.
It automatically deletes unused buffers.
