Make more Color constructors const fn

[arendjr]

Objective

I regularly copy-paste color codes to my game and try to use them in const values. These color codes are often in hex format, so converting them to floating points is annoying. Color::srgb_u8() provides a relative convenient alternative, except it's not a const fn.

Solution

This PR makes the Color::srgb_u8() and Color::srgba_u8() constructors const fns, making their use easier in constants.

Testing

I think this is one of those cases where we can say, if it compiles, it works :)

[arendjr]

Ah, nevermind. I had overlooked the issue with floating point arithmatic in const fn :(

[Luracasmus]

Ah, nevermind. I had overlooked the issue with floating point arithmatic in const fn :(

Will this be fixed by rust-lang/rust#128596 ?

I really like the idea of making more of Bevy const

[arendjr]

Sounds like it would! I don’t actually know what’s Bevy’s policy on supporting older Rust compilers, but it would be great if we could have this soon(ish).

[Luracasmus]

According to the README, Bevy's MSRV is close to the latest release, so this might even be able to be merged almost right away when 1.82 becomes stable!