Game Mechanics: AC may not be working correctly

[nilbog]

Originally Posted by Alecta [You must be logged in to view images. Log in or Register.]

Nilbog said he was fine with it, waiting on permission from Rogean.

Again, I'm pretty new here and am really just supposed to work on PvP stuff, so I am not comfortable posting other peoples contributions to the code base.

I do not mind sharing the information for collaborative efforts to improve it. I feel as though we have enough people here to contribute.

[Treats]

Originally Posted by Alecta [You must be logged in to view images. Log in or Register.]

Disclaimer: I cant step through my debugger right now, it's late, and I am out of town for the week, so this information might be wrong.

The AC system isn't very clean, but from what I can tell:

• The shield AC isnt handled any differently from normal AC
• Soft caps arent in place (?)

These are both due to the fact that the "NPC hitting a target" code uses the AC variable (which is what is displayed client side) and doesnt use the RealAC variable (which is what takes into account soft caps, shield AC, etc).

Also, I'd ignore the #ac_test command since that simulates "Player attacking something" and not "NPC attacking something" - and those follow different code paths.

NPC::ProcessAttack -> Mob::MeleeMitigation -> defender->GetAC()
vs
Client::ProcessAttack -> Client::ThrowATKvAC_D20I -> defender->GetRealAC()

Off topic: I am curious if the Monk AC bonus is working properly all the time. It seems that due to the order the bonuses are calculated, it might not be.

Anyway, will post more when I have more time to dig into this.

(Don't use anything from my previous post here in the Bug forums about AC, some of it is not correct)

Player vs NPC AC

NPC AC is easy to calculate but the problem is determining the value of their Mitigation AC from Equipment
NPC Avoidance AC = Agility from Table + (Defense * 16/9)
NPC Mitigation AC = (Buffs/4) + (Defense/3) + (Equipment * 4/3)

NPC's rarely wear any armor. The only thing I could think of that NPCs would have used was the max capped value for their level. This would be determined in relation to whether they were a Melee or a Caster.

Melee (non casters)

60 - 289
59 - 275
58 - 261
57 - 247
56 - 233
55 - 219
54 - 205
53 - 191
52 - 177
51 - 163
50 - 149 or 50 - 160
40 - 119 or 40 - 130
30 - 89 or 30 - 100
20 - 59 or 20 - 70
10 - 29 or 10 - 40
1 - 2 or 1 - 10

Caster (Nec/Wiz/Mag/Ench)

60 - 385
59 - 366
58 - 348
57 - 329
56 - 310
55 - 292
54 - 273
53 - 254
52 - 236
51 - 217
50 - 198
40 - 158
30 - 118
20 - 78
10 - 38
1 - 2

So an Enchanter NPC that is level 42 would have 166 Raw AC for Mitigation -- Just like a player wearing that amount of Hardcapped Raw Mitigation AC. This would also explain why Trakanon Mitigated damage so well, I think he was classified as a fucking Necro (lol) so his Mitigation AC was off the charts.

Bonuses

These are the three bonuses that I know of (think there is one more):

Iksar Bonus (Level / 2) + 5 added to Mitigation
Monk Bonus ((Level + 5) * 4) / 3 to Mitigation
Rogue bonus ((Level + 5) * 4) / 3 to Mitigation

Hardcaps/Softcaps

In reality there should not be any Total Hardcaps or Softcaps
Defense Skill is capped per level
Agility is capped at 255
Melee Raw AC is capped per level
Caster Raw AC is capped per level
Buffs Values are exact depending on Spell

Player AC

NPC::ProcessAttack -> Mob::MeleeMitigation -> defender->GetAC()

This needs to totally be reworked from the ground up, its fucked here.

[Furniture]

How much of the code was changed from the original eqemu ac code? I am very familiar with AC code on eqemu and i'm sure you guys have changed it somewhat since i remember at the start of this server ac wasnt working at all and one of the patch notes said that you guys had fixed ac to be more important

can you let us know what exactly did you guys change? original eqemu code does definitely have the softcaps and shield ac code in place so unless you removed them I don't see how they wouldnt still be there

[Jimjam]

If AC doesn't work how come there seems to be decent mitigation at lower levels?

Is there a component to mitigation besides worn AC (ignoring spells) that is more effective at lower levels? or does NPC attack outscale player AC too much at higher levels?

[Fregar]

All of this sounds classic to me o.0
Is it how AC should work in a modern game? No.
Is it how it worked in 2000-2001 Everquest? I think so.

I used to play SK on live Velious/SOL/POP, doing raids Mostly. Had lvl 40-50ish ench/wiz/clr/war alts too.

If I remember correctly, AC had a soft cap, and past that cap you had to stack a huge amount of it to make even a small difference.
Thats the reason why I used skyshrine armor over kael one.
And we didn't bother with shields either.

This is from a sk point of view of course, I don't remember details about warriors MT'ing Vyemm and AoW.

If someone would do some parsing to show AC is or is not broken, It would better be done with a lvl 40 plate class from naked to full stuff vs a sabrethooth tiger imo.

[Thulack]

Originally Posted by Fregar [You must be logged in to view images. Log in or Register.]

All of this sounds classic to me o.0
Is it how AC should work in a modern game? No.
Is it how it worked in 2000-2001 Everquest? I think so.

I used to play SK on live Velious/SOL/POP, doing raids Mostly. Had lvl 40-50ish ench/wiz/clr/war alts too.

If I remember correctly, AC had a soft cap, and past that cap you had to stack a huge amount of it to make even a small difference.
Thats the reason why I used skyshrine armor over kael one.
And we didn't bother with shields either.

This is from a sk point of view of course, I don't remember details about warriors MT'ing Vyemm and AoW.

If someone would do some parsing to show AC is or is not broken, It would better be done with a lvl 40 plate class from naked to full stuff vs a sabrethooth tiger imo.

Shield Always added AC even after softcap. Thats why everyone always stuck their highest AC aug(yes later on down the line) in their shield slot.

[Splorf22]

Did you actually read this thread?

[Fregar]

Originally Posted by Splorf22 [You must be logged in to view images. Log in or Register.]

Did you actually read this thread?

Yes, what do you think is wrong in what I said?

Your testing on the cliff golem tells us that either AC is broken OR there is some sort of cap in effect in this specific case.

Someone else did some testing at lower level vs a freeport guard, and his results show AC is working in this specific case.

This leads toward AC not beeing broken, but capped.

To the real question: is it classic or not?

Unless someone dig up an old post from 2000 we'll have to rely on what peoples remember from that time.
What I can tell about 2001-2002 (so not 2000, but close after) is that my personal feeling at that time was that HP>AC past a certain amount of AC.

[baalzy]

Originally Posted by Fregar [You must be logged in to view images. Log in or Register.]

Yes, what do you think is wrong in what I said?

Your testing on the cliff golem tells us that either AC is broken OR there is some sort of cap in effect in this specific case.

Someone else did some testing at lower level vs a freeport guard, and his results show AC is working in this specific case.

This leads toward AC not beeing broken, but capped.

To the real question: is it classic or not?

Unless someone dig up an old post from 2000 we'll have to rely on what peoples remember from that time.
What I can tell about 2001-2002 (so not 2000, but close after) is that my personal feeling at that time was that HP>AC past a certain amount of AC.

What does a soft cap have to do with taking increased damage when your AC is increased, if anything it should stay the same?

[Jimjam]

Originally Posted by baalzy [You must be logged in to view images. Log in or Register.]

What does a soft cap have to do with taking increased damage when your AC is increased, if anything it should stay the same?

Phrased like that it sounds the soft cap* is subtracting diminishing returns instead of adding it?

*which shouldn't exist in this time period, there should be a hard cap by level on worn.