Level 5 Shield Boomerang damage calculation

[kysp]

I wanted to know the damage formula for level 5 shield boomerang (without considering the defence of who takes it), because the skill description isn't clear enought.

By the description, shield weight and refine rate improves the 250% of ATK damage (at level 5). But how?

I've searched on google only to realize that there are other people wanting to know that. I've managed (maybe) to solve this by looking at the code of eathena (found in http://code.google.com/p/eathena-project...txt&r=4172 at battle.c).

I don't know if it's the correct formula, but appears that it's something like:

damage = (ATK * 250%) + (shield.weight/10) + (10 * refine),

where by ATK I mean pure Atk (without Atk modifiers, e.g, Pirate Dagger etc.).

Based on this (look at the reference code bellow):

ATK_ADD(10*sd->status.inventory[index].refine);

and

ATK_ADD(sd->inventory_data[index]->weight/10);

For exemple, with 265 atk and + 4 shield (130 weight) we should have: damage = (265 * 2.5) + (130/10) + (10 * 4) = 715.5.

Testing with some monsters shows that it's pretty accurate, e.g, in poring it does 714 damage, and he haves 1 vit . Remeber that shield boomerang ignores size modifiers.

It's nice to know that formula, because with it you realize that it's better (with respect to damage of shield boomerang) to have a + 10 guard (30 weight) than a + 4 shield (130 weight), wich gives 103 and 53 added damage, respectively.

But here's the question: when I tryed shield boomerang with 266 atk and + 4 Cross Shield (200 weight, increase by 30% the damage of shield boomerang) on poring, it does 1131 damage while by the formula: damage = [(266 * 2.5) * 1.3] + (200/10) + (10 * 4) = 924.5. So what's the correct way to calculate the 30% increase, or if it's wrong, what is the correct formula?

For curiosity and reference, here is the code:

lines 1332 - 1345

Code:

case CR_SHIELDBOOMERANG:
case PA_SHIELDCHAIN:
...
        if (index >= 0 && sd->inventory_data[index] &&
sd->inventory_data[index]->type == 5)
            ATK_ADD(sd->inventory_data[index]->weight/10);
        break;
}

and lines 1943 - 1949

Code:

if (skill_num == CR_SHIELDBOOMERANG ||
skill_num == PA_SHIELDCHAIN) { //Refine bonus applies after
cards and elements.
    short index= sd->equip_index[8];
    if (index >= 0 && sd->inventory_data[index] && sd->inventory_data[index]->type == 5)
        ATK_ADD(10*sd->status.inventory[index].refine);
}

[Menace651]

I think the 30% increase in damage is only applied to the total damage before refinement and weight. I could be wrong. But that's why the damage from refinement and weight on shields is kind of sucky. Regardless, you won't see much difference in damage between a +7 and +10 refined shield. +ATK and +%Damage gears/cards and STR will add more damage than weight and refinement. But If you are a perfectionist and want that +9 or +10 and can afford it, then by all means go for it. I usually settle for a +7 or +8 refine.

On a side note Shield Boom also works with status cards and Earth Deleter Cards. Slot an Earth Deleter in Zodiac Wings and go hunt stuff that you can one shot and not have to worry about SP. I haven't tried Shield Boom/Chain with Def piercing or IcePick effect gears but would be curious to see if they work.

[Ptah]

I think he's onto something, if it's skill damage increase I don't see why you'd only multiply the atk part.

[kysp]

I think the 30% increase in damage is only applied to the total damage before refinement and weight. I could be wrong. But that's why the damage from refinement and weight on shields is kind of sucky. Regardless, you won't see much difference in damage between a +7 and +10 refined shield. +ATK and +%Damage gears/cards and STR will add more damage than weight and refinement. But If you are a perfectionist and want that +9 or +10 and can afford it, then by all means go for it. I usually settle for a +7 or +8 refine.

Aplying the 30% increase to the total damage gives 942,5. I'm starting to think that this formula is wrong

I can't afford +10 items yet, so went testing on rms test server. To my suprise (contradicting the exemple) + 4 Shield does more damage than + 10 Guard, providing more evidence it's wrong.

On a side note Shield Boom also works with status cards and Earth Deleter Cards. Slot an Earth Deleter in Zodiac Wings and go hunt stuff that you can one shot and not have to worry about SP. I haven't tried Shield Boom/Chain with Def piercing or IcePick effect gears but would be curious to see if they work.

After reading about yours Ice Pick and Def Piercing thoughts I got renoved faith in shield boo. But with ice pick it don't work, at least on rms test server. But didn't tested def piercing.

Anyway, the Earth Deleter/Zodiac Wing idea is really nice!

[kysp]

I think I've figured it out for the case with the + 4 Cross Shield. The formula is:

damage = [(ATK * 250%) + 5] * 160% + (shield.weight/10) + (10 * refine).

And yes, it implies that Cross Shield does 60% increase instead of the 30% in the description. That's odd.

For exemple, with 265 ATK with + 4 Cross Shield on monster Drops (0 DEF, 3 Vit): damage = (1068 + 20 + 40) - 3 = 1128 - 3 = 1125 by the formula. I tested it on poring island (on hero) and it does exactly 1125 all the times.

I compared the results given by the formula for Poporing and Poring with empirical testing (for each one), and the damage is the same!

You may wonder where did i came with the + 5 in the expression and the 60% increase. First, I suspected the % increase was wrong, so solved an equation using the real damage I was getting in the game for an unknow x being the % increase. You get a value approximately 160%. So by intuition I added 5 to the "first" damage, and redoing the calculator job, it matched perfectly.

I think the + 5 is from the +4 refine, so if you have + 5 refine, use + 6, etc.

I don't have another Cross Shield with different refine to test. So please, someone test it!

[kysp]

I think he's onto something, if it's skill damage increase I don't see why you'd only multiply the atk part.

Because there's a comment in the code: "Refine bonus applies after
cards and elements". I think the same applies for weight bonus. And the description of CS says "Increase damage of ..., and Shield Boomerang by 30%". So you multiply the damage given.

[mariaflores]

Can someone clarify the correct formula for calculating the 30% damage increase from a +4 Cross Shield (200 weight) in Shield Boomerang? The calculated value doesn't match the observed damage output, so I'm curious about the accurate calculation method. Thanks!