Health regeneration

This page discusses how the player health regeneration mechanism works, and how equipment and buffs affect the regeneration rate.

If the player is not hit for some time, health starts regenerating until the player is hit, and the pace at which he regenerates is dependent on:
 * 1) Player's maximum health: higher health means higher regeneration
 * 2) Movement: if the player is standing still, the regeneration rate is 2.5x higher
 * 3) Time since the last hit: the longer ago, the higher the regeneration rate; this has a cap of 600 in-game seconds (10 in-game minutes), after which the regeneration rate no longer rises
 * 4) Buffs and debuffs: for a feel you can have a look at the detailed explanation below, but keep in mind that the numbers do not represent health regeneration directly; they are just factors (higher is better)

The time the player has to wait until regeneration starts is highly variable from roughly 1/10th of a second to 17 seconds (32 seconds on expert mode) and is again dependent on maximum life, movement, and buffs/debuffs.

Details
Health regeneration (HR) is determined by the following formula: and gives the health per second the player regenerates.

The formula can be split in to 5 parts: The Player will regenerate HR per second (discounting 2 buffs (Shiny Stone, Rapid Healing)). This means if the Player has HR=0.5 it will regain 1 health per 2 seconds and if the player has HR=5 it will regain 5 health per second. Technical the player will not gaining 5 health per second instead he will get 1 health every 12 ticks (game time > 1 second = 60 ticks)
 * 1) *mHP: maximum Health of the player
 * 2) *eRT: factor for the time that passed until the last hit. A detailed definition can be found in the detailed explanation
 * 3) *As eRT starts at 0 and than rises by 1 first every 5 seconds and after 30 seconds every 10 seconds to a maximum of 9. (0<=eRT<=9) (excluding the Shiny Stone buff where it can raise till 38). That means the this part is 0 for at least 5 seconds
 * : formula from part 1
 * : modifiers from the buffs and debuffs at least in most parts some buffs are effecting other parts not represented in this description (see technical description). This is the easiest part as the buffs are just added to the regeneration
 * : formula from part 2
 * : either 0.5 if the player is moving or 1.25 if the player is standing still
 * : 1, except if the player is in expert mode and has not the well fed buff, then it is 0.5
 * : formula from part 3
 * 1) * round the result to the nears whole number
 * : formula from part 4
 * 1) * to get the health regeneration per second
 * : formula from part 3
 * 1) * round the result to the nears whole number
 * : formula from part 4
 * 1) * to get the health regeneration per second
 * 1) * to get the health regeneration per second

Technical explanation
The player has these health regeneration stats:
 * Regeneration Time (RT): How long the character has been regenerating for. This normally increases +1 per tick, capped at 3600, and resets to zero when the character takes damage (stopping regeneration).
 * Regeneration Rate (R): Hit Points (HP) regenerated per tick (1 point of R is equal to 0.5 HP/s). This increases the longer the RT (the longer the player has been avoiding damage).
 * Regeneration Counter (RC): Increases by R per tick, becomes 120 or over, or -120 or less, it will be reduced or increased by 120, and player will gain or lose 1 health.

The Regeneration Rate (R) determines how fast the RC changes. R is normally 0 or positive, but could be negative if the player is inflicted with any life-draining debuffs, like Poisoned.

Calculation
The base Regeneration Rate (R) is mainly determined by the Regeneration Time (RT), player's max Health (mHP), and whether player is standing or moving.

First, The RT is converted to an Effective Regeneration Time (eRT).
 * If RT <= 1800, each 300 RT boosts eRT +1.
 * If RT > 1800, each 600 RT boosts eRT +1.

Here is an illustration of the relationship between RT and eRT:

Then, the base Regeneration Rate Finally, it will be rounded to the nearest whole number.
 * If the player is standing still, R will be multiplied by 1.25.
 * If the player is moving, it will be multiplied by 0.5.

So, for a brief conclusion: the longer player not getting hurt, the higher maxim health player has, the higher for the natural health regeneration rate. Also, standing still(using an item or not) give a 2.5X healing bonus comparing to keep moving.

In addition, if the player is in Expert mode and does not have a Well Fed buff, R will be additionally multiplied by 0.5.

Item and buff effects
R is also affected by other items and buffs.

Note: Despite drowning being similar to life-draining debuffs, it only resets the RT and does not affect the RC and R. It directly reduces Hit Points instead.

Buffs
These apply if the player doesn't have any life-draining debuffs:

Regen debuffs

 * Feral Bite debuff: Base R is multiplied x0.5.
 * Bleeding debuff: Keeps RT reset to 0, so base R remains at 0.

Life-draining debuffs
These cancel the R boosts above, reset RT to 0, and reduce R by these values:
 * Poisoned: -4
 * On Fire!: -8
 * Venom, Cursed Inferno, Frostburn: -12
 * Burning: -60
 * Suffocation: -40.
 * Electrified: -8 (when standing still), or -32 (when moving).
 * The Tongue: -100 only in Expert Mode.

Honey

 * Which means Honey reduces the rate of any life-draining debuff.
 * Honey additionally boosts RT +2 per tick (RT increase is 3x as fast).

Shiny Stone
If the player is using items and almost standing still (it allows small amounts of movement), it will reset the multipliers of the Feral Bite debuff and Expert Mode to 0.75 from 0.5. Both of them only reduce the regeneration speed by 25% instead of the previous 50%. It will also multiply base R x1.1.

If the player is not using any items and almost standing still, the following effects are applied in addition to those above:
 * 1) If the player has any life-draining debuffs so that R is less than 0, R is reduced by half (if you also have Honey buff, then it increases R by 4 first(but no more than 0), then, R is reduced by half, finally, the Honey buff additionally increase R by 2.).
 * 2) R +4.
 * 3) RT +4 per tick.
 * 4) If 90 < RT < 1800, RT is reset to 1800.
 * 5) When RT > 3000, it will remove the RT cap, and every 300 RT above 3000 will boost eRT +1 (this part is capped at 30, so it will give an eRT maxed at 38 instead of the previous 9).
 * 6) Finally, if R > 0, RC is boosted +1 per tick.

So, if the player is at 600 max HP, with the Shiny Stone and standing still, in Expert mode, without Well Fed:
 * RC is additionally boosted +1 per tick
 * = 32 Hit Points per second regeneration rate.
 * = 32 Hit Points per second regeneration rate.

A more complex example
To illustrate how the items, buffs and debuffs interact with each other, here is a more complex example:

Assume the player is having Venom, On Fire!, Regeneration and Honey buff, equipping Shiny Stone and Charm of Myth, Standing next to a Heart Lantern, and standing still.

It would work in the step shown below: So, player has R=0, and will neither gain or lose health.
 * 1) The Regeneration buff and Charm of Myth increase the R by 4 and 1 respectively, so, R=5.
 * 2) The life-draining debuffs cancel the effect above and set R to 0.
 * 3) The Venom and On Fire! reduce R by 12 and 8 respectively, so, R=-20.
 * 4) As the R<0, the Honey buff increased the R by 4, so, R=-16.
 * 5) As the R is still less than 0, the Shiny Stone reduces it by half, so, R=-8.
 * 6) Then the Honey, Shiny Stone and Heart Lantern increase R by 2, 4 and 2 respectively, so, R=0.
 * 7) As player have life-draining debuffs, the RT will remain 0, so player would get any natural health regeneration.
 * 8) As R is not more than 0, the Shiny Stone won't provide the RC +1 per tick bonus.

Then, if player place a Campfire nearby, it will give R +1 boost and give player a 0.5 HP/s regeneration rate; in addition, as R>0, the Shiny Stone will now provide the RC +1 per tick bonus, which means an additional 0.5 HP/s regeneration rate. So, player will have a 1 HP/s regeneration rate.

However, if player is have Rapid Healing buff (which gives the RC +6 per tick effect and does not affect R) instead of the Campfire, the Shiny Stone won't provide the RC +1 per tick bonus. So player will finally get a 3 HP/s regeneration rate.