gb_gen_range_isze generates random values outside of its range

[OetkenPurveyorOfCode]

isize gb_random_range_isize(gbRandom *r, isize lower_inc, isize higher_inc) {
	u64 u = gb_random_gen_u64(r);
	isize i = *cast(isize *)&u; // may be negative if u64 has a bit pattern corresponding to a negative isize
	isize diff = higher_inc-lower_inc+1;
	i %= diff; // modulus of negative i can happen here
	i += lower_inc;
	return i; 
}

A possible fix could be:

isize gb_random_range_isize(gbRandom *r, isize lower_inc, isize higher_inc) {
	u64 u = gb_random_gen_u64(r);
	usize diff = higher_inc-lower_inc+1;
	u %= diff;
	u += lower_inc;
	return cast(isize)u;
}

But you may want to look into better debiasing or faster biased random number within range generation: https://www.pcg-random.org/posts/bounded-rands.html