melee hit probability

[Tibarius]

I am just wondering ... my rogue can use the Heroism Spell from the Magic book #8. It raises my total melee to-hit about 10% (from around 120 to 132). The hit probability shown in the Monster recal Information just raises from 82 to 83%, for a randomly choosen Opponent.

So what is the main hit probability modifier??? Character-level?

[kaypy]

This is one of those seriously messy calculations.

Its a bit easier to start with the numbers on the character screen. You have a base skill to-hit and a plus/minus. Each point of the plus/minus actually affects the base skill by 3. If that is less than 9, make it 9. This is the base chance.

Now, the actual hit probability is
90 * (base chance - (2/3 * enemy armour)) / base chance + 5
except that you are always given at least 12%

Now back to those initial numbers. The base skill to hit is the sum of your racial and class skills and the increase you get every 10 levels. See the character creation help for details on that.

The to-hit numbers are everything else like
equipment to hit
buffs
debuffs
dexterity
strength
etc

If you need to know more, stare at obj-info.c/describe_hitchance and calcs.c/calc_bonuses until your eyes glaze over. If you stare long enough, you will lose all desire to know more.

[Derakon]

This kind of crap is why I agitate for making your hit probability be

75% + accuracy bonuses - enemy evasion

And then you make accuracy bonuses on equipment rare and not very big, and most enemies don't have much evasion. Warriors could get an innate +10% (and rogues/paladins +5%), and maybe mages/priests get -5%.

[Timo Pietilä]

This kind of crap is why I agitate for making your hit probability be

75% + accuracy bonuses - enemy evasion

I would like to make AC having two values, evasion and absorption. Absorption could work as all-around damage drainer from area effect too, while evasion prevents damage entirely if you manage to evade the blow. Evasion increases with skill and dexterity so melee-kind of classes and races get better at it sooner.

Dragons, for example, would be rather easy to hit (I imagine), but actually damage them would require either big damage or slay to make any difference. Grand Master Mystic would be very very hard to hit at all, but rather fragile if you manage to land a blow.

I think that absorption is now abstracted behind the HP of the creature, but maybe it could be part of the players gear as well. You actually directly increase your HP by wearing heavy armor, and not just from getting more CON and character level.

....maybe I'm describing totally new game here though. Resulting change would be rather fundamental for angband. OTOH, I can see how this could be balanced so that it makes a rather steady progressing game: items get better the deeper you go, heavy armor hinders magic so magic-users end up with less HP and so on.

[mushroom patch]

The way angband combat currently works is pretty good. While it's difficult to get a feel for how things like hit probabilities really work, you normally get pretty good hit rates and pluses have a noticeable impact, especially heroism/bless/berserk strength.

One of the main merits of angband combat is that it's based around multiple strikes with a relatively large number of dice and reasonably high hit rates. This makes it easy to get a feel for how fights are going within a few turns.

re: EV and AC, I think there's some danger in fiddling with hit probabilities independent of damage absorption. High miss percentages + high damage hits make for wonky combat, especially when you have several blows per turn.

[quarague]

The evasion + absorption approach exists, ADOM has that for example, so you can definitely make a balanced roguelike with that mechanic. It would be quite a significant change from current angband though.
I'm not sure how far I agree with the claim that current hit probabilities work well. It is true that non melee classes have considerably worse hit chances than melee classes in the early game. However the effect that they usually get only 1 hit per turn while warriors tend to get 3 from level 1 makes a much bigger difference than the hit probability. At least for me, the hit chance also ceases to be relevant in the middle and late game, presumably a level 40 gnome mage still has less hit probability than a level 40 HT warrior, but I don't think it makes any difference for game play. I use potions of berserk strength and heroism only for the healing and fear effects and have not found the to hit and AC modifiers to make any real difference. In my experience, the bless spell is rather useless, I would need much stronger effects (for a shorter time period) to make use of it.

[Derakon]

If you stack blessing, heroism, and berserker, then you get something like +30-40 to-hit. This will increase your hit probability by maybe 5% against a deep enemy. I'm not saying that's irrelevant, but accuracy bonuses don't make much of an apparent difference in combat. I can't believe that it's impossible or even at all difficult to scrap the current accuracy system in favor of the one I described.

Absorption is a separate issue, IMO. I wouldn't mind seeing it go in, but I don't think it's necessarily tightly-bundled to the issue of how to handle the player's hit rate.

[Tibarius]

re: to-hit modifiers like bless/heroism etc.

I can only agree to the fact that increasing to-hit seems largely irrelevant to me. I do not care to improve my to-hit prob. by 1%. Casting those spells is too much work for the effort they bring.

[Ingwe Ingweron]

If you stack blessing, heroism, and berserker, then you get something like +30-40 to-hit. This will increase your hit probability by maybe 5% against a deep enemy. I'm not saying that's irrelevant, but accuracy bonuses don't make much of an apparent difference in combat. I can't believe that it's impossible or even at all difficult to scrap the current accuracy system in favor of the one I described.

Absorption is a separate issue, IMO. I wouldn't mind seeing it go in, but I don't think it's necessarily tightly-bundled to the issue of how to handle the player's hit rate.

I have to agree, Derakon. The current to-hit seems largely irrelevant. Not that I don't do those buffs if I have the chance, but they don't make much difference. I've always found it strange that =Slaying is always trumped by =Damage, even though slaying is the "deeper" ring. To my mind to-hit should be more relevant.

[TJS]

This kind of crap is why I agitate for making your hit probability be

75% + accuracy bonuses - enemy evasion

And then you make accuracy bonuses on equipment rare and not very big, and most enemies don't have much evasion. Warriors could get an innate +10% (and rogues/paladins +5%), and maybe mages/priests get -5%.

Something needs to be done about the current hit system. In your example how much difference would +1 to-hit make?

I thought currently warriors do much better than 15% difference in hit chance compared to a mage so am unsure about your modifiers.

A lot of numbers could do with being scaled down really, for example AC normally ends up in the hundreds.

[Derakon]

Something needs to be done about the current hit system. In your example how much difference would +1 to-hit make?

I thought currently warriors do much better than 15% difference in hit chance compared to a mage so am unsure about your modifiers.

A lot of numbers could do with being scaled down really, for example AC normally ends up in the hundreds.

Warriors have much higher innate melee skill and have higher DEX, so their chance to hit is generally 10-15% higher than an equivalently-leveled mage's chance.

+1 to-hit in the current system makes much less than 1% of an improvement in your chance to hit. In the system I proposed, though, a +1 to-hit would increase your to-hit percentage by exactly 1. Of course that means that to-hit bonuses must be handed out sparingly...but that makes rings of Accuracy / Slaying much easier to quantify.

[TJS]

Warriors have much higher innate melee skill and have higher DEX, so their chance to hit is generally 10-15% higher than an equivalently-leveled mage's chance.

+1 to-hit in the current system makes much less than 1% of an improvement in your chance to hit. In the system I proposed, though, a +1 to-hit would increase your to-hit percentage by exactly 1. Of course that means that to-hit bonuses must be handed out sparingly...but that makes rings of Accuracy / Slaying much easier to quantify.

Agreed that the current system is too opaque. Your idea is definitely an improvement, although 1% for each to-hit still seems a little on the stingy side.

I guess it would need evasion and absorption of damage to be split up for that to work (or at least a reworking of AC).

[Tibarius]

re: evasion and absorption

I like the idea of Splitting Evasion and Absorption of armor. Kinda odd to see rogues in full-plate mails. Heavy armour could receive a Speed Penalty. -5 Speed for a full-plate for example.

[EpicMan]

Part of the problem is that both +to-hit and +damage basically do the same thing - they reduce the time it takes you to kill some monster via melee or shooting, and are both opposed by monster AC and HP.
To-hit can be increased to reduce the number of misses, and therefore the time it takes to kill a monster, up to the cap of 95% accuracy. Damage can be increased to reduce the number of hits needed to kill the monster, up to one-hit-one-kill.
Monster AC can be increased to increase the number of misses, extending the time to kill, and HP increases the total amount of damage to kill it.

Only real difference between AC and HP is that AC only protects against melee attacks; magic (after resistances/vulnerabilities) and shooting directly affect HP.

[Timo Pietilä]

If you stack blessing, heroism, and berserker, then you get something like +30-40 to-hit. This will increase your hit probability by maybe 5% against a deep enemy. I'm not saying that's irrelevant, but accuracy bonuses don't make much of an apparent difference in combat. I can't believe that it's impossible or even at all difficult to scrap the current accuracy system in favor of the one I described.

Hitting things is more a skill than bonus in late game. In early game that's reversed. I don't think that's in any way wrong, just hard to put in numbers, but I don't care so much about numbers anyway. I go what I feel is best.