Damage Formulas 101

Discussion in 'RPG Maker MV Tutorials' started by Skunk, Jul 28, 2017.

  1. Skunk

    Skunk Melody Master Veteran

    Messages:
    1,063
    Likes Received:
    368
    Location:
    The Island
    First Language:
    English/Slavic
    Primarily Uses:
    RMMV
    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.

    [​IMG]


    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
    < - less than
    >= more than or equal to
    <= less than or equal to
    === equal to
    && and
    || or
    !== not equal
    ! not

    Examples:

    v[10] > 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 10 is less 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] <== 100 ? 1000 : 100; (If variable is 100 or less, it'll deal 1000 damage, else it'll only deal 100)

    v[10] === 100 ? 1000: 100; (If variable is equal to 100, 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 percent, e.g. 1.0, 0.5, 0.75, 2.44 would be 100%, 50%, 75%, 244%)

    hit - Hit rate
    eva - Evasion rate
    cri - Critical rate
    cev - Critical evasion rate
    mev - Magic evasion rate
    mrf - Magic reflection rate
    cnt - Counter attack rate
    hrg - HP regeneration rate
    mrg - MP regeneration rate
    trg - TP regeneration rate

    SParams:(All decimal numbers symbolizing percent, e.g. 1.0, 0.5, 0.75, 2.44 would be 100%, 50%, 75%, 244%)

    tgr - Target Rate
    grd - Guard effect rate
    rec - Recovery effect rate
    pha - Pharmacology
    mcr - MP Cost rate
    tcr - TP Charge rate
    pdr - Physical damage rate
    mdr - Magical damage rate
    fdr - Floor damage rate
    exr - Experience rate

    How about changing HP/MP/TP?

    gainHp(value) - restores HP by value
    gainMp(value) - restores MP by value
    gainTp(value) - restores TP by value

    setHp(hp) - sets HP to value
    setMp(mp) - sets MP to value
    setTp(tp) - sets TP to value
    E.g. a.setHp(a.mhp)
    E.g. a.setHp(a.hp + 100)

    clearTp() - sets TP to 0


    What about advanced stuff where you can influence formulas with states?

    We got all that!
    isStateAffected(stateId) - checks if battler has state inflicted to them.
    E.g. b.isStateAffected(10) ? 10000 : 1;

    isDeathStateAffected() - checks if battler has death state inflicted to them.
    E.g. b.isDeathStateAffected() ? 10000 : 1;

    resetStateCounts(stateId) - refreshes how long state will last for the battler
    if (b.isStateAffected(10)) b.resetStateCounts(10); 100

    updateStateTurns() - shortens all states on battler by 1 turn
    b.updateStateTurns(); 100

    addState(stateId) - adds state to the battler
    if (!b.isStateAffected(10)) b.addState(10); 100

    isStateAddable(stateId) - checks if state can be added to the battler
    c=100; if (b.isStateAddable(10)) b.addState(10); else c=4000; c

    removeState(stateId) - removes state from the battler
    if (a.isStateAffected(10)) a.removeState(10); 0



    What about buffs? Can we buff and debuff battlers?

    Yes!
    addBuff(paramId, turns) - adds a buff for a parameter
    a.addBuff(0, 3); b.def*10

    addDebuff(paramId, turns) - adds a debuff for a parameter
    b.addDebuff(2, 10); 9999

    removeBuff(paramId) - removes a buff or debuff from a battler
    removeAllBuffs() - removes all buffs and debuffs from a battler

    Parameter IDs

    0 - Max HP
    1 - Max MP
    2 - Attack
    3 - Defence
    4 - Magic Attack
    5 - Magic Defence
    6 - Agility
    7 - Luck

    General Battler Stuff

    die() - kills the battler
    b.die(); 0

    revive() - revives the battler
    a.revive(); 1000

    paramBase(paramId) - gets base parameter
    a.paramBase(3)*10 - b.def*2

    paramPlus(paramId) - gets the bonus of parameter
    a.paramPlus(3)*2 - b.def*2

    paramMax(paramId) - gets max possible value of parameter
    b.paramMax(0)

    elementRate(elementId) - checks element rate of the battler (rate being decimal numbers representing %)
    b.elementRate(10) >== 0.5 ? 10000 : a.mat*4;

    isStateResist(stateId) - checks whether the battler resists state
    c=0; b.isStateResist(10) ? c+=2000 : b.addState(10); c

    isSkillTypeSealed(stypeId) - checks if battler's skill type is sealed
    isSkillSealed(skillId) - checks if battler's skill is sealed
    isEquipTypeSealed(etypeId) - checks if battler's equip type is sealed
    isDualWield() - checks if battler can dual wield
    isGuard() - checks if battler is guarding
    recoverAll() - removes all states, restores HP and MP to max

    hpRate() - checks HP rate of battler
    mpRate() - checks MP rate of battler
    tpRate() - checks TP rate of battler
    b.hpRate() < 0.5 ? b.hp-1 : 100;

    isActor() - checks if battler is actor
    isEnemy() - checks if battler is enemy
    escape() - escapes from battle
    b.escape() (makes enemy run away)

    consumeItem(item) - eat up an item
    a.consumeItem($dataItems[15]); 100



    For actor only:

    currentExp() - current EXP
    currentLevelExp() - EXP needed for current level
    nextLevelExp() - EXP needed for next level
    nextRequiredExp() - EXP left until next level
    maxLevel() - max level of actor
    isMaxlevel() - is actor max level (true/false)
    hasWeapon() - is actor wielding a weapon (true/false)
    hasArmor() - is actor wearing any armor (true/false)
    clearEquipments() - unequip everything actor is wearing
    isClass(gameClass) - checks if actor is of a class (gameClass - $dataClasses[ID])
    hasNoWeapons() - checks if actor doesn't have any weapons
    levelUp() - levels actor up
    levelDown() - level actor down
    gainExp(exp) - gives actor exp
    learnSkill(skillId) - makes actor learn a skill
    forgetSkill(skillId) - makes actor forget a skill
    isLearnedSkill(skillId) - checks if actor has a skill learned
    actorId() - returns Actor's ID


    For enemy only:
    enemyId() - returns Enemy's ID

    What about Math? Can we use Math methods inside the formula?

    Yup, you totally can.

    Math.random() - returns a random number between 0 and 1 (0 <= n < 1)
    Math.min(numbers) - returns a minimum number from provided numbers.
    E.g. Math.min(10, 50, 40, 200) - would return 10.

    Math.max(numbers) - returns a maximum number from provided numbers.
    E.g. Math.max(10, 50, 40, 200) - would return 200.

    Math.round(number) - rounds a number to nearest integer.
    Math.ceil(number) - rounds the number up to nearest integer.
    Math.floor(number) - rounds the number down to nearest integer.

    Math.rand() returns a number between 0 and 1, but can we get a random number between 1 and 100? Or 5 and 200?

    No problem:

    Math.floor(Math.random()*100)+1
    ^ That would return a number between 1 and 100. If we didn't add 1 at the end, it'd only return a number between 0 and 99.

    But that's a lot of text? Could we simplify somehow?

    Thankfully, there's a method in rpg_core.js that adds Math.randomInt(max);
    So we can write the same using:
    Math.randomInt(100)+1
     
    #1
  2. Pentacles

    Pentacles Lazy Creator Veteran

    Messages:
    46
    Likes Received:
    19
    Location:
    France
    First Language:
    French
    Primarily Uses:
    RMMV
    Wow. Don't know what to say. It's ... Very complete ...
    How much time did you make to list every formula '-' ? 48 days ?
    anyways, it can be helpfull. Like , REALLY.
     
    #2
  3. Tea's Jams

    Tea's Jams Veteran Veteran

    Messages:
    671
    Likes Received:
    1,741
    First Language:
    English
    Primarily Uses:
    RMMV
    Yay! Thank you for this!!!!
     
    #3
  4. Kevin Hirst

    Kevin Hirst Veteran Veteran

    Messages:
    81
    Likes Received:
    10
    First Language:
    English
    Primarily Uses:
    RMMV
    Is it possible to use the combined stats of the entire party, or even other characters besides the user (a) and target (b)?
    Like a special ability that adds up the attack stat of the entire party. I tried to use party.atk but that does not work.

    Would i have to use actor.id somehow to call on one their stats, or maybe use a variable?
    Or is this just impossible to do.
     
    #4
  5. cjewell77

    cjewell77 Veteran Veteran

    Messages:
    65
    Likes Received:
    3
    Location:
    Shreveport LA
    First Language:
    English
    Let me ask this question... What do you think of using yanfly's armor scaling instead of - formulas? I have a fairly balanced system but there are instances where armor scaling balances it better... Does anyone have experience with the armor scaling?
     
    #5
  6. bhindi1224

    bhindi1224 NOT Indian Okra Veteran

    Messages:
    295
    Likes Received:
    166
    First Language:
    English
    Primarily Uses:
    RMMV
    #6
  7. cjewell77

    cjewell77 Veteran Veteran

    Messages:
    65
    Likes Received:
    3
    Location:
    Shreveport LA
    First Language:
    English
    ave
    am i what?
     
    #7
  8. bhindi1224

    bhindi1224 NOT Indian Okra Veteran

    Messages:
    295
    Likes Received:
    166
    First Language:
    English
    Primarily Uses:
    RMMV
    was asking @Skunk . The same post is on another forum with the name glasses.
     
    #8
  9. Garthedes82

    Garthedes82 Villager Member

    Messages:
    5
    Likes Received:
    1
    First Language:
    English
    Thanks for this.
     
    #9
  10. ty66kill

    ty66kill Villager Member

    Messages:
    22
    Likes Received:
    1
    Last edited: Apr 9, 2018
    #10
  11. Cecelemon

    Cecelemon Warper Member

    Messages:
    1
    Likes Received:
    0
    First Language:
    Spanish
    Primarily Uses:
    RMMV
    With this formulas can i change the element resistance?
     
    #11
  12. Eliaquim

    Eliaquim Veteran Veteran

    Messages:
    197
    Likes Received:
    28
    Location:
    Brazil - Rio de Janeiro
    First Language:
    Portuguese - Br
    Primarily Uses:
    RMMV
    Based on that format - "statement ? formula1 : formula2;"

    i made this formula:

    b.isEnemy() && b.isDead() ? b.exp() / a.level : b.result().hpDamage * 1;

    So, see if i'm right:

    b is an enemy and be is dead ?
    If yes, so it will be given the base xp / for the user level.
    If not, it will give the damage dealt on the enemy * 1.

    If i want to give the exp only for the actor who performed the action?
     
    #12
  13. AlecWallace

    AlecWallace Villager Member

    Messages:
    5
    Likes Received:
    1
    First Language:
    English
    Primarily Uses:
    RMMV
    Sorry, wrong thread
     
    #13

Share This Page