cc69fdd0c6
2 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Zachary Harrold
|
cc69fdd0c6
|
Add no_std support to bevy (#17955)
# Objective - Fixes #15460 (will open new issues for further `no_std` efforts) - Supersedes #17715 ## Solution - Threaded in new features as required - Made certain crates optional but default enabled - Removed `compile-check-no-std` from internal `ci` tool since GitHub CI can now simply check `bevy` itself now - Added CI task to check `bevy` on `thumbv6m-none-eabi` to ensure `portable-atomic` support is still valid [^1] [^1]: This may be controversial, since it could be interpreted as implying Bevy will maintain support for `thumbv6m-none-eabi` going forward. In reality, just like `x86_64-unknown-none`, this is a [canary](https://en.wiktionary.org/wiki/canary_in_a_coal_mine) target to make it clear when `portable-atomic` no longer works as intended (fixing atomic support on atomically challenged platforms). If a PR comes through and makes supporting this class of platforms impossible, then this CI task can be removed. I however wager this won't be a problem. ## Testing - CI --- ## Release Notes Bevy now has support for `no_std` directly from the `bevy` crate. Users can disable default features and enable a new `default_no_std` feature instead, allowing `bevy` to be used in `no_std` applications and libraries. ```toml # Bevy for `no_std` platforms bevy = { version = "0.16", default-features = false, features = ["default_no_std"] } ``` `default_no_std` enables certain required features, such as `libm` and `critical-section`, and as many optional crates as possible (currently just `bevy_state`). For atomically-challenged platforms such as the Raspberry Pi Pico, `portable-atomic` will be used automatically. For library authors, we recommend depending on `bevy` with `default-features = false` to allow `std` and `no_std` users to both depend on your crate. Here are some recommended features a library crate may want to expose: ```toml [features] # Most users will be on a platform which has `std` and can use the more-powerful `async_executor`. default = ["std", "async_executor"] # Features for typical platforms. std = ["bevy/std"] async_executor = ["bevy/async_executor"] # Features for `no_std` platforms. libm = ["bevy/libm"] critical-section = ["bevy/critical-section"] [dependencies] # We disable default features to ensure we don't accidentally enable `std` on `no_std` targets, for example. bevy = { version = "0.16", default-features = false } ``` While this is verbose, it gives the maximum control to end-users to decide how they wish to use Bevy on their platform. We encourage library authors to experiment with `no_std` support. For libraries relying exclusively on `bevy` and no other dependencies, it may be as simple as adding `#![no_std]` to your `lib.rs` and exposing features as above! Bevy can also provide many `std` types, such as `HashMap`, `Mutex`, and `Instant` on all platforms. See `bevy::platform_support` for details on what's available out of the box! ## Migration Guide - If you were previously relying on `bevy` with default features disabled, you may need to enable the `std` and `async_executor` features. - `bevy_reflect` has had its `bevy` feature removed. If you were relying on this feature, simply enable `smallvec` and `smol_str` instead. --------- Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com> |
||
|
Zachary Harrold
|
a64446b77e
|
Create bevy_platform_support Crate (#17250)
# Objective - Contributes to #16877 ## Solution - Initial creation of `bevy_platform_support` crate. - Moved `bevy_utils::Instant` into new `bevy_platform_support` crate. - Moved `portable-atomic`, `portable-atomic-util`, and `critical-section` into new `bevy_platform_support` crate. ## Testing - CI --- ## Showcase Instead of needing code like this to import an `Arc`: ```rust #[cfg(feature = "portable-atomic")] use portable_atomic_util::Arc; #[cfg(not(feature = "portable-atomic"))] use alloc::sync::Arc; ``` We can now use: ```rust use bevy_platform_support::sync::Arc; ``` This applies to many other types, but the goal is overall the same: allowing crates to use `std`-like types without the boilerplate of conditional compilation and platform-dependencies. ## Migration Guide - Replace imports of `bevy_utils::Instant` with `bevy_platform_support::time::Instant` - Replace imports of `bevy::utils::Instant` with `bevy::platform_support::time::Instant` ## Notes - `bevy_platform_support` hasn't been reserved on `crates.io` - ~~`bevy_platform_support` is not re-exported from `bevy` at this time. It may be worthwhile exporting this crate, but I am unsure of a reasonable name to export it under (`platform_support` may be a bit wordy for user-facing).~~ - I've included an implementation of `Instant` which is suitable for `no_std` platforms that are not Wasm for the sake of eliminating feature gates around its use. It may be a controversial inclusion, so I'm happy to remove it if required. - There are many other items (`spin`, `bevy_utils::Sync(Unsafe)Cell`, etc.) which should be added to this crate. I have kept the initial scope small to demonstrate utility without making this too unwieldy. --------- Co-authored-by: TimJentzsch <TimJentzsch@users.noreply.github.com> Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com> Co-authored-by: François Mockers <francois.mockers@vleue.com> |