This patch includes a number of changes to encourage reading and writing
buffers through mapping rather than copying data as before.
This includes a new `BufWrite` abstraction which is designed for filling
buffers. It behaves much like a Vec<u8>, but with fixed capacity.
This gets it working on mac. Also delete old implementation.
There's also an update to winit 0.25 in here, because it was easier to
roll forward than fix inconsistent Cargo.lock. At some point, we should
systematically update all deps.
Reuse submitted command buffers rather than continually allocating them.
This patch also improves the story across the different backends. On
DX12 it was reusing allocators without resetting them, which could be a
leak. And on Metal the reset "fails," so there's always a new alloc.
This patch deallocates command buffers after command submission completes (the same time as other resources are released).
It should be portable and robust on all back-ends, but not necessarily the most efficient. But reuse of command buffers, as well as more efficient allocation on Vulkan and DX12, are for followup work.
This gets a swapchain displayed and fills out a number of the image
related parts of the API: image creation, binding to descriptor sets,
and blitting.
Add workgroup size to dispatch call (needed by metal). Change all fence
references to mutable for consistency.
Move backend traits to a separate file (move them out of the toplevel
namespace in preparation for the hub types going there, to make the
public API nicer).
Add a method and macro for automatically choosing shader code, and
change collatz example to generate all 3 kinds on build.
A bunch of loose ends remain, including needing to plumb the size of the
workgroup through. Image and swapchains also need to be added. But it
does run collatz.
Progress towards #95.
