`bevy_color`'s operations are not stable across all hardware due to use of trigonometric float methods

[BenjaminBrienen]

Bevy version

Commit 87afa98

[Optional] Relevant system information

DxDiag.txt

Lenovo Thinkbook Pro Gen 3
Razer Core X Chroma with an RTX 2060
Samsung Odyssey Neo G9 54"

What you did

Ran cargo run -p ci -- test

What went wrong

---- oklcha::tests::test_to_from_srgba_2 stdout ----
thread 'oklcha::tests::test_to_from_srgba_2' panicked at crates\bevy_color\src\oklcha.rs:415:13:
gray: Oklcha { lightness: 0.5981808, chroma: 2.3841858e-7, hue: 0.0, alpha: 1.0 } != Oklcha { lightness: 0.5981807, chroma: 9.424322e-8, hue: 18.434948, alpha: 1.0 }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

failures:
oklcha::tests::test_to_from_srgba_2

Additional information

This is not on main. It is on https://github.com/BenjaminBrienen/bevy/tree/rename-add-to-enqueue

[alice-i-cecile]

This is super mysterious: my guess is on a floating point implementation or something being inconsistent.

[BenjaminBrienen]

Also happens on the (currently) latest commit ca6056d

[alice-i-cecile]

So it's probably not a cosmic ray 😂

[workingjubilee]

@BenjaminBrienen What OS? Ah, DxDiag, so Windows?

[workingjubilee]

This test involves transcendental functions which have an implementation which varies from operating system to operating system, because they are implemented within software and do not have a specific degree of precision they are evaluated to. The way to make the test deterministic is to make sure that you know exactly which implementation you are using, or to accept imprecision.