Use compute pass for tests in tests subdir. This is also shaking out some issues that weren't apparent from just collatz.
In particular, we need more autorelease pools to prevent things from leaking. As of this commit, the "clear" test runs correctly but the others haven't yet been converted to the compute_pass format.
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.
There's a bit of reorganizing as well. Shader stages are made available
from piet-gpu to the test rig, config is now a proper structure
(marshaled with bytemuck).
This commit just has the transform stage, which is a simple monoid scan
of affine transforms.
Progress toward #119
Reduce allocation of descriptor heaps. This change also enables clearing
of buffers, as the handles are needed at command dispatch time.
Also updates the tests to use clear_buffers on DX12. Looking forward to
being able to get rid of the compute shader workaround on Metal.
This is a followup on #125, and progress toward #95
This is our version of the standard message passing litmus test for
atomics. It does a bunch in parallel and permutes the reads and writes
extensively, so it's been more sensitive than existing tests.
Add a clear stage and associated tests, and also use it on non-Vulkan
backends to clear the state buffer.
While that's a workaround and will go away when we implement the actual
clear command, it's also a nice demo of how the new "stage" structure
composes.
