Cleanup lmms_math.h

[Rossmaxx]

Cleaned up some legacy code from lmms_math.h

[Rossmaxx]

I would like to wait for #7380 before this PR.

[Rossmaxx]

I have decided to clean up more mathematical stuff.

[sakertooth]

Not much to add, Dom covered most of what needed to be said already.

[Rossmaxx]

@DomClark we good for merge? I'm waiting for your nod.

[DomClark]

Did you plan to use std::copysign? I thought you said that it looked okay to use (it does to me).

[Rossmaxx]

No i said I'm not sure about the sign. There's chances negative values might be used. I don't wanna take much chances.

[DomClark]

There's chances negative values might be used.

There isn't - std::sqrt(std::abs(val)) and std::pow(std::abs(v), e) are guaranteed to be non-negative for all values of val, v, and e. You always get a non-negative value from std::abs, and powers and square roots of non-negative numbers are themselves non-negative. Conceptually, what this code does is strip the sign, perform the operation using the non-negative value, then restore the original sign. This is a typical use for std::copysign - as an example, I used it like this in Sf2Player here:

lmms/plugins/Sf2Player/Sf2Player.cpp

Lines 760 to 765 in 35f350e

	const auto panning = n->panning;
	const auto factor = 1.f - std::abs(panning) / static_cast<float>(PanningRight);
	const auto balance = std::copysign(
	factor <= 0 ? maxBalance : std::min(-200.f * std::log10(factor), maxBalance),
	panning
	);

[Rossmaxx]

A bit late but thanks for the info. I'll keep it in mind for the future.