fix: impossible hibernation

[leoCottret]

Summary

SUMMARY: Bugfixes "Fix impossible hibernation"

Fixes #2010

Purpose of change

1. Hibernation could only be triggered with an obscure system taking into account the possible calories you could burn in a day. Even if it could be triggered, the mechanic wasn't clear enough for the average player

Describe the solution

• now you can hibernate when you're above 90% of maximum stored calories, it's just as simple as that
• it was also impossible to hibernate since your character would wake up after your fatigue level reached 0. I added an extra condition to ignore the fatigue level
• also, the rate of hunger was divided by 7 when hibernating, but it did close to nothing. I even tried to reduce it by 100000, this didn't change a thing. So I used a system to compensate the lost calories, taking into account the metabolic rate of the player

Describe alternatives you've considered

• fixing the bug that makes hunger rate modifications ignored (instead of my 3rd change in Describe the solution)

Testing

• Tested with light eater, fast metabolism, very fast metabolism, high thirst
• Being either too thirsty or hungry will wake you up
• With very fast metabolism, you can almost go through the 7 days of hibernations, from 17500 to ~8000 calories

[Coolthulhu]

the rate of hunger was divided by 7 when hibernating, but it did close to nothing. I even tried to reduce it by 100000, this didn't change a thing. So I used a system to compensate the lost calories, taking into account the metabolic rate of the player

That would suggest something is not working right. This needs to be tested and either fixed or at least made known.

[leoCottret]

I suppose it's due to a rounding to 1 (probably from the function that updates the stomach).
Setting it to 0 does stop the calories consumption, but anything slightly above will give a similar consumption.

[scarf005]

Testing

1. changed time to day 0, 00:00:00.
2. added bear trait
3. resetted all basic needs.
4. slept.
5. was able to hibernate ~7 days.

Describe Changes

turns out kcal_per_time did not take account of rates.hunger because it used Character::bmr(). at first naively tried kcal_per_time * rates.hunger but it didn't work because it squared metabolic_rate_base.

kcal_per_time 
= bmr() * N
= metabolic_rate_base() * N

rates.hunger
= calc_needs_rates()
= metabolic_rate() * N
= metabolic_rate_base()

therefore, kcal_per_time * rates.hunger = metabolic_rate_base() ^ 2 * N

extracted value into metabolic_base_kcals and multiplied it instead.

Alternatives

buff hibernation metabolic rate further from current 2 to 2.x?

[chaosvolt]

The missile is eepy