The current plan is to more or less follow the wgpu/wgpu-hal approach. In the mux/backend layer (which corresponds fairly strongly to wgpu-hal), there isn't explicit construction of a compute encoder, but there are new methods for beginning and ending a compute pass. At the hub layer (which corresponds to wgpu) there will be a ComputeEncoder object.
That said, there will be some differences. The WebGPU "end" method on a compute encoder is implemented in wgpu as Drop, and that is not ideal. Also, the wgpu-hal approach to timer queries (still based on write_timestamp) is not up to the task of Metal timer queries, where the query offsets have to be specified at compute encoder creation. That's why there are different projects :)
WIP: current state is that stage-style queries work on Apple Silicon, but non-Metal backends are broken, and piet-gpu is not yet updated to use new API.
This puts most of the infrastructure in place but I'm hitting an error
that "sampleCountersInBuffer is not supported on this device".
The issue is that M1 supports stage boundaries and not command boundaries.
We'll have to rework the logic a bit. (And, in the most general case, support
both)
Start implementing stage boundaries, but it will probably require an API
change.
This exposes interfaces to render glyphs into a texture atlas. The main changes are:
* Methods to plumb raw Metal GPU resources (device, texture, etc) into piet-gpu-hal objects.
* A new glyph_render API specialized to rendering glyphs. This is basically the same as just painting to a canvas, but will allow better caching (and has more direct access to fonts, bypassing the Piet font type which is underdeveloped).
* Ability to render to A8 target in addition to RGBA.
WIP, there are some rough edges, not least of which is that the image format changes are only on mac and cause compile errors elsewhere.
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.
Use an array of bindtypes rather than the previous situation, which was
a choice of buffer counts, or a heavier builder pattern.
The main thing this unlocks is distinguishing between readonly and
read/write buffers, which is important for DX12.
This is WIP, the Metal part hasn't been done, and the old stuff not
deleted.
Part of #125
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.
