Damage Formulas 101

Skunk · 2017-07-28T16:33:52+0900

Please note: A discussion has already been started about different things you can do with these formulas so please direct those comments and question to the appropriate thread. https://forums.rpgmakerweb.com/index.php?threads/rmmv-damage-formula-ideas-and-help.47099/ A link to the list of script equivalents of event commands https://forums.rpgmakerweb.com/index.php?threads/rpg-maker-mv-script-call-list.46456/ Damage Formulas 101 MV Edition You probably wondered how to make a skill do more damage against enemies with a state, or heal more if player has a state, or deal exactly half of enemy's HP. And so on. All of that and more can be done through custom damage formula. Basics: Type - sets what does the formula damage or heal. None - Nothing, no damage will be dealt. HP Damage - HP will be damaged MP Damage - MP will be damaged HP Recover - HP will be restored MP Recover - MP will be restored HP Drain - Deals damage to enemy HP and restores that much HP for attacker MP Drain - Deals damage to enemy MP and restores that much MP for attacker Element - Sets which element to use. Normal attack - means will use same element as weapon. Variance - How will damage fluctuate. E.g. If skill formula says it deals 100 damage and variance is 20%, the skill will deal between 80 and 120 damage. Critical - Can skill critically hit, dealing increased damage by 300%. And now, the actual fun part - formulas! It decides how much damage will opponent take or ally will heal. Let's dissect one of basic formulas that come with RPG Maker MV - Fire 100 + a.mat * 2 - b.mdf * 2 What do things like a and b mean? a - attacker b - defender So if Actor Glasses were to cast Fire on a Slime. a would be Glasses and b would be Slime. Meaning the takes double of Glasses mat (Magic Attack) parameter and subtracts double of Slime's mdf (Magic Defense) parameter and adds that to the 100 in the beginning ofthe formula. E.g. Glasses has 100 mat and Slime has 20 mdf. If we were to convert fomula using those numbers, we'd have - 100 + 100*2 - 20*2, after calculation we see with those parameters Fire would deal 260 damage if there were no variance. But only last number in the formula deals damage. If you had 2 lines of formula. (semicolon ; tells where line ends for the program) E.g. a.atk; a.atk*2 Only a.atk*2 would be calculated for damage. Are there more letters other than a and b for the formulas? Yes. There are variables. Which are used like this: v[ID]. ID - index of the variable. So you could have a skill that gets stronger the higher variable is. E.g. v[10] * 2 - b.def * 3 Is there a way to make skill even more complex, e.g. if some variable is over 100, deal extra damage? Yes, in that case we can use if else statements. How if else statement looks: Code: Code (Text): if (statement) { formula1; } else { formula2; } But how to write it to the damage formula? It only has 1 line! Just write everything together~ Code (Text): if (statement) { formula1; } else { formula2; } E.g.: Code (Text): if (v[10] > 100) { a.atk*4 - b.def*2 } else { a.atk*2 - b.def*2 } Which can be shortened to this if you're using only 1 line of formula. Code (Text): if (statement) formula1; else formula2; E.g.: Code (Text): if (v[10] > 100) a.atk*4 - b.def*2; else a.atk*2 - b.def*2; And you can shorten it even further using ternary operator (my favorite one): statement ? formula1 : formula2; E.g.: Code (Text): v[10] > 100 ? a.atk*4 - b.def*2 : a.atk*2 - b.def*2; Symbols for statements: > - more than = more than or equal to 100 ? 1000 : 100; (If variable 10 is more than 100, it'll deal 1000 damage, else it'll only deal 100) v[10] == 100 ? 1000 : 100; (If variable is 100 or more, it'll deal 1000 damage, else it'll only deal 100) v[10] 50 && v[11] >== 25 ? 1000 : 100; (If variable 10 is more than 50 and variable 11 is 25 or more, it'll deal 1000 damage, else it'll only deal 100) v[10] > 50 || v[11] > 50 ? 1000 : 100; (If variable 10 is more than 50 or variable 11 is more than 50 then it'll deal 1000 damage, it'll only deal 100) v[10] !== 100 ? 1000 : 100; (If variable 10 is not equal to 100, it'll deal 1000 damage else it'll only deal 100) What about parameters to use for a and b? Here's a whole list of them: Current: (All flat numbers, e.g.: 900, 999, 11) level - current level (Actor only by default) hp - current hp mp - current mp tp - current tp Params: (All flat numbers, e.g.: 1337, 7331, 156) mhp - max hp mmp - max MP atk - attack def - defence mat - magic attack mdf - magic defence agi - agility luk - luck XParams: (All decimal numbers symbolizing pe…

● ARCHIVED · READ-ONLY

Started by Skunk Jul 28, 2017, 07:33 AM 281 posts Page 14 of 15 View original ↗

Sunlo

#261 Oct 23, 2023, 01:43 AM Source

I used this formula for actor 2 "b.actorId() == 2 ? -10 : 50" but instead of causing damage it just doesn't heal but it does heal everyone else which is good but it should cause damage for actor 2. Maybe I didn't input the formula right.
ATT_Turan

#262 Oct 23, 2023, 01:48 AM Source

@Sunlo Why didn't you post this in the thread you made where you asked about this and I suggested that formula? It always makes more sense to keep a topic in one place.

I missed that evalDamageFormula() prevents healing from going into negative just like damage.

So to do what you want, you'd need to use a plugin like VisuStella Battle Core and change the damage value after it's calculated.
nbgamemaker

#263 Oct 23, 2023, 02:13 AM Source

this was a very useful tutorial.
H-and-R-Writers-Block

#264 Jan 15, 2024, 07:22 PM Source

I totally understood all that, *sweats as he tries to be convincing.* Heh I read all those formula's though, very in depth. I imagine it was aimed at MZ but I'm currently on VX Ace, I have MZ but have not started working on that yet. I was just ghosting about here to see if someone was having the same issue, but this is much more advanced then what I'm trying to figure out.

I was just trying to see if there was a means within the RPG Maker VX itself to make it to where no matter how weak an enemy is, they always do 1 damage at the least. If that was covered in all that....*shudders* math, up there then It clearly went over my head, not hard considering I'm a rodent...ha!
ATT_Turan

#265 Jan 15, 2024, 07:45 PM Source
H-and-R-Writers-Block said:
I imagine it was aimed at MZ

H-and-R-Writers-Block said:
I was just trying to see if there was a means within the RPG Maker VX itself to make it to where no matter how weak an enemy is, they always do 1 damage at the least.
From the first post, "Math.max(numbers) - returns a maximum number from provided numbers."

Googling the Ruby version of that:
Code:
[your formula, 1].max
Zakarijazh

#266 Jan 27, 2024, 08:38 PM Source

Where would I put the Math.round(number) in this formula so it stops showing decimals?

a.gainHp(- a.hp / 4); a.hp / 5

The skill sacrifices the user's HP to restore a smaller amount to the target.
Robro33

#267 Jan 27, 2024, 08:53 PM Source

around any bit of math that can produce a decimal, but isnt a part of the final damage/heal as that is already rounded
a.gainHp(-Math.round(a.hp / 4)); a.hp / 5
Dark_Ansem

#268 Jan 28, 2024, 08:50 AM Source

Robro33 said:
around any bit of math that can produce a decimal, but isnt a part of the final damage/heal as that is already rounded
a.gainHp(-Math.round(a.hp / 4)); a.hp / 5
I think you need to encase everything within math.round unless you using Visustella
Zakarijazh

#269 Jan 28, 2024, 10:38 AM Source

Dark_Ansem said:
I think you need to encase everything within math.round unless you using Visustella
Thank you, it seems to work fine as is, though :D (I'm not yet using visustella)

Robro33

#270 Jan 28, 2024, 11:01 AM Source

Dark_Ansem said:

I think you need to encase everything within math.round unless you using Visustella

by default, the last step the engine takes before completing damage a calc is to round the result. its why you can feed a decimal directly into the formula box, and if its a part of the final damage calc, it doesnt give a decimal ingame, but if you put any code before it that to do anything else, you have to round it manually

Default Damage Steps

Code:

Game_Action.prototype.makeDamageValue = function(target, critical) {
    var item = this.item();
    var baseValue = this.evalDamageFormula(target);
    var value = baseValue * this.calcElementRate(target);
    if (this.isPhysical()) {
        value *= target.pdr;
    }
    if (this.isMagical()) {
        value *= target.mdr;
    }
    if (baseValue < 0) {
        value *= target.rec;
    }
    if (critical) {
        value = this.applyCritical(value);
    }
    value = this.applyVariance(value, item.damage.variance);
    value = this.applyGuard(value, target);
    value = Math.round(value);
    return value;
};

Zakarijazh

#271 Jan 28, 2024, 11:45 AM Source

My other question is how could I take this

a.gainHp(-Math.round(a.hp)); a.hp

and make it damage the enemy?

It's a self-sacrifice skill but the current formula accounts for damage after the user loses their HP, resulting in '0' damage to the enemy.

Sorry, trying to do as much as I can skill-wise w/o using plugins.
Gensun

#272 Jan 28, 2024, 11:50 AM Source

Zakarijazh said:
My other question is how could I take this

a.gainHp(-Math.round(a.hp)); a.hp

and make it damage the enemy?

It's a self-sacrifice skill but the current formula accounts for damage after the user loses their HP, resulting in '0' damage to the enemy.

Sorry, trying to do as much as I can skill-wise w/o using plugins.
Try storing a.hp into a temporary variable
var dmg = a.hp; a.gainHp(-Math.round(a.hp)); dmg
Zakarijazh

#273 Jan 28, 2024, 12:09 PM Source

Zakarijazh said:

Gensun said:
Try storing a.hp into a temporary variable
var dmg = a.hp; a.gainHp(-Math.round(a.hp)); dmg
Yes! perfect! Thanks so much! :D

Gensun said:
Try storing a.hp into a temporary variable
var dmg = a.hp; a.gainHp(-Math.round(a.hp)); dmg
When I use this in battle, the user is not able to be revived using items or skills, despite it showing the normal Death state after user?

I also created an MP-sacrifice skill that seems to work fine?
Gensun

#274 Jan 28, 2024, 01:05 PM Source

Zakarijazh said:
When I use this in battle, the user is not able to be revived using items or skills, despite it showing the normal Death state after user?

I also created an MP-sacrifice skill that seems to work fine?
I tested it on my blank project. I cannot replicate this bug.
Zakarijazh

#275 Jan 28, 2024, 07:12 PM Source

Gensun said:
I tested it on my blank project. I cannot replicate this bug.
I just figured it out. I had the healing skills/items set to 'ally' and not 'Ally (dead)'
JorgeBonito

#276 Feb 21, 2024, 01:27 PM Source

Is there a way to make an attack use Damage HP when against a certain actor but use Damage MP against another one?
ATT_Turan

#277 Feb 21, 2024, 01:36 PM Source

JorgeBonito said:
Is there a way to make an attack use Damage HP when against a certain actor but use Damage MP against another one?
The problem with that is the damage type is determined by what you select in the database.

So you could set it to HP Damage and use script calls in the formula to take MP instead, but there are two issues:
1 - You'd see a 0 damage popup for the HP
2 - You should not put script calls that change anything into the damage formula, because they'll be executed when the game evaluates that skill during enemy turns or Auto Battling.

I think you'd be better off giving it no damage type in the database, then using Yanfly's Action Sequence to program out the skill and figure out how to code damage execution inside of that.

And yes, that is as complicated as it sounds.

You could also try putting a Yanfly Auto Passive State on the target that uses Buffs and States Core notetags to convert the HP damage into MP damage and try to deactivate the HP popup.
JorgeBonito

#278 Feb 21, 2024, 02:32 PM Source

ATT_Turan said:
The problem with that is the damage type is determined by what you select in the database.

So you could set it to HP Damage and use script calls in the formula to take MP instead, but there are two issues:
1 - You'd see a 0 damage popup for the HP
2 - You should not put script calls that change anything into the damage formula, because they'll be executed when the game evaluates that skill during enemy turns or Auto Battling.

I think you'd be better off giving it no damage type in the database, then using Yanfly's Action Sequence to program out the skill and figure out how to code damage execution inside of that.

And yes, that is as complicated as it sounds.

You could also try putting a Yanfly Auto Passive State on the target that uses Buffs and States Core notetags to convert the HP damage into MP damage and try to deactivate the HP popup.
Since the character I want to use this on is a character that has 0 HP but receives damage on MP, the Buffs and States Core made the trick. Just added a Invisible Status with a Respond Effect that gains the negative value of the damage.
Jaykov

#279 Mar 1, 2024, 03:08 AM Source

Is V[10] the variable for the damage calculated?
ATT_Turan

#280 Mar 1, 2024, 03:34 AM Source

Jaykov said:
Is V[10] the variable for the damage calculated?
Sorry, what are you talking about?

There is no V in the damage formula, only v. And v[10] is game variable ID 10.