Changing the tears stat

Author(s): catinsurance
Tags:

---

Creating an item that gives a simple tears up or down is more complex than it may appear.

Explanation

Making a simple item like Sad Onion is actually a bit complicated, because the tears stat as displayed in the FoundHud in Repentance(+) is not the same as what we change internally.

The game uses something called MaxFireDelay, or tear delay, which is the minimum amount of game updates (30 game updates per second) before another tear can be fired. You can find more information about it here, on the wiki.

The in-game display of the tears stat is your tears per second, or your fire rate. To get the tears per second from the MaxFireDelay, use the following:

local function toTearsPerSecond(maxFireDelay)
  return 30 / (maxFireDelay + 1)
end

Conversely, you can get the MaxFireDelay from the tears per second using the following:

local function toMaxFireDelay(tearsPerSecond)
  return (30 / tearsPerSecond) - 1
end

Example

Now we can put it all together. The following is technically a "fire rate" up, since a "tears up" follows the soft cap of 5 (depending on the character you're playing).

local mod = RegisterMod("My Mod", 1)
local HAPPY_ONION = Isaac.GetItemIdByName("Happy Onion")
local HAPPY_ONION_TEARS = 1.1

local function toTearsPerSecond(maxFireDelay)
  return 30 / (maxFireDelay + 1)
end

local function toMaxFireDelay(tearsPerSecond)
  return (30 / tearsPerSecond) - 1
end

function mod:SadOnionStats(player, cacheFlag)
  local count = player:GetCollectibleNum(HAPPY_ONION)
  local tearsPerSecond = toTearsPerSecond(player.MaxFireDelay)
  tearsPerSecond = tearsPerSecond + (count * HAPPY_ONION_TEARS)
  player.MaxFireDelay = toMaxFireDelay(tearsPerSecond)
end

mod:AddCallback(ModCallbacks.MC_EVALUATE_CACHE, mod.SadOnionStats, CacheFlag.CACHE_FIREDELAY)

---