0349809420
# Objective
Different platforms use their own implementations of several
mathematical functions (especially transcendental functions like sin,
cos, tan, atan, and so on) to provide hardware-level optimization using
intrinsics. This is good for performance, but bad when you expect
consistent outputs across machines.
[`libm`](https://github.com/rust-lang/libm) is a widely used crate that
provides mathematical functions that don't use intrinsics like `std`
functions. This allows bit-for-bit deterministic math across hardware,
which is crucial for things like cross-platform deterministic physics
simulation.
Glam has the `libm` feature for using [`libm` for the
math](d2871a151b/src/f32/math.rs (L35))
in its own types. This would be nice to expose as a feature in
`bevy_math`.
## Solution
Add `libm` feature to `bevy_math`. We could name it something like
`enhanced-determinism`, but this wouldn't be accurate for the rest of
Bevy, so I think just `libm` is more fitting and explicit.
31 lines
1.1 KiB
TOML
31 lines
1.1 KiB
TOML
[package]
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name = "bevy_math"
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version = "0.12.0"
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edition = "2021"
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description = "Provides math functionality for Bevy Engine"
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homepage = "https://bevyengine.org"
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repository = "https://github.com/bevyengine/bevy"
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license = "MIT OR Apache-2.0"
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keywords = ["bevy"]
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[dependencies]
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glam = { version = "0.24.1", features = ["bytemuck"] }
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serde = { version = "1", features = ["derive"], optional = true }
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[features]
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serialize = ["dep:serde", "glam/serde"]
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# Enable approx for glam types to approximate floating point equality comparisons and assertions
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approx = ["glam/approx"]
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# Enable interoperation of glam types with mint-compatible libraries
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mint = ["glam/mint"]
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# Enable libm mathematical functions for glam types to ensure consistent outputs
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# across platforms at the cost of losing hardware-level optimization using intrinsics
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libm = ["glam/libm"]
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# Enable assertions to check the validity of parameters passed to glam
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glam_assert = ["glam/glam-assert"]
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# Enable assertions in debug builds to check the validity of parameters passed to glam
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debug_glam_assert = ["glam/debug-glam-assert"]
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[lints]
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workspace = true
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