bevy_kana 0.0.2

Ergonomic, opinionated utilities for Bevy — type-safe math, input wiring, and more
Documentation

bevy_kana

Ergonomic, opinionated utilities for Bevy — type-safe math, input wiring, and more.

CI crates.io docs.rs license

Work in progress. This crate is in active development (v0.0.2) and not subject to semver stability guarantees. APIs will change without notice between commits. Do not depend on this in production code yet.

仮名 (kana) — from Japanese 仮 (ka, "simplified, borrowed") + 名 (na, "name, character"). The kana writing systems — hiragana (ひらがな) and katakana (カタカナ) — were born as simplified characters borrowed from complex kanji, making written language more accessible without losing meaning.

bevy_kana follows the same philosophy: small, named abstractions borrowed from Bevy's existing types, making game code more expressive and type-safe without adding complexity. It is a growing collection of ergonomic utilities — not limited to any single category.

What's in the box

Semantic math types

Zero-cost newtype wrappers around Bevy's math primitives that prevent accidental mixing at compile time.

Type Wraps Purpose
Position Vec3 A point in 3D space
Displacement Vec3 A delta or offset
Velocity Vec3 Rate of position change
ScreenPosition Vec2 Pixel-space coordinates
Orientation Quat A rotation

Key properties:

  • Deref to the inner type — access .x, .length(), .dot() directly
  • From/Into both directions — easy interop with Bevy APIs
  • Type-safe arithmetic — Position + Position works, Position + Velocity won't compile
  • Reflect support — compatible with Bevy's reflection and inspector tools
use bevy::math::Vec3;
use bevy_kana::Position;
use bevy_kana::Velocity;

let p1 = Position(Vec3::new(1.0, 0.0, 0.0));
let p2 = Position(Vec3::new(3.0, 0.0, 0.0));

// Same-type arithmetic works
let centroid = (p1 + p2) / 2.0;

// Cross-type mixing is a compile error
// let bad = p1 + Velocity(Vec3::X); // ERROR

Numeric cast traits

Convenience traits that replace bare as casts for common numeric conversions, centralizing the clippy #[allow] so call sites stay clean.

Trait From Suppresses
ToF32 i32, u32, usize cast_precision_loss
ToI32 usize, u32, f32 cast_possible_truncation, cast_possible_wrap
ToU32 usize, f32, f64 cast_possible_truncation, cast_sign_loss
ToUsize u32, f32 cast_possible_truncation, cast_sign_loss

These conversions are deliberately lossy. They will silently produce wrong results if the input exceeds the target type's representable range. It is the caller's responsibility to ensure values are in bounds. Typical safe usage: loop indices, mesh vertex counts, and other small geometry values.

use bevy_kana::ToF32;
use bevy_kana::ToU32;

let sides: u32 = 8;
let angle = (j.to_f32() / sides.to_f32()) * std::f32::consts::TAU;
let index = positions.len().to_u32();

More to come

bevy_kana will grow to include other convenience macros and generic utilities that are broadly useful across Bevy projects.

Version Compatibility

bevy_kana Bevy
0.0.1-0.0.2 0.18

Usage

Add to your Cargo.toml:

[dependencies]
bevy_kana = "0.0.2"

Run the example:

cargo run --example basics

License

Licensed under either of

at your option.