Frogcomposband mechanics questions

[Saru]

Picked up frog a couple months back, and have accrued a large number of questions I've been meaning to ask, so I'll just dump them here I apologize if the list gets really long or rambly. Thanks in advance!

1. Is there a formula to calculate the probability of a monster saving against a given spell based on the spell's `power` and the monster's level? I know that more power = better, but that's about it.

2. Similarly, how does player saving throw work internally? is it similar to V where you can get 100% resist, or is it based on the monster's spell `power` as well?

3. Is there any use for the various statues of enemies I find? I know figurines give pets, but haven't found a use for statues. I thought maybe they'd give you full monster memory of that monster somehow, but haven't been able to test it yet.

4. How much does slow monster slow the monster?

5. How does monster stunning work? Do they have increasing levels of severity like the player, or is it just duration based flat debuffs? And what kind of penalties exactly does stunning inflict on the monster? same as V?

6. For staves of confusing lights, do all the status effects have the same odds of being saved against, or are some easier than others? I've consistently gotten a power 160 or 200 staff to stun and terrify target creatures, but the slowing and stasis appears to happen much less, especially against tough enemies like archliches.

7. How do I deal with monsters using dispel magic on me? Do I ever get a saving throw, or is it just their way of saying 'ha ha you suck now'

8. How do vampiric weapons work, especially when they have other brands as well? Do I heal the full damage dealt from all blows, or just a portion?

That's all for now, I did try to hunt through the source code for answers to a few of these but it gets complicated really fast. I'd appreciate it if someone with a bit more experience with frog could help me. Thanks!

[Sideways]

1. Is there a formula to calculate the probability of a monster saving against a given spell based on the spell's `power` and the monster's level? I know that more power = better, but that's about it.

To some extent it depends on what the spell does, as the Confusing Lights answer below shows. There is a "standard" monster save (which compares the monster's level, boosted for uniques, against the player's level, sometimes boosted by a bonus from on a relevant stat) but many effects have their own individual saves that may depend on the effect's power, the player's level, both or something else. A fairly common power-dependent save (used by for example Slow) is monster level vs. 1d(power-10)+10.

2. Similarly, how does player saving throw work internally? is it similar to V where you can get 100% resist, or is it based on the monster's spell `power` as well?

The saving throw formulas can vary slightly depending on the situation, but the most basic is that you have a X% chance of saving where X is your saving throw, multiplied by 100, divided by 100+Y where Y is a boost that depends on the monster and situation. Most commonly Y equals the monster's level divided by 2.

The Free Action save formula is similar but slightly different (it rolls a random integer between 0 and (100+Y-1) and compares it to your saving throw). That save gets called once for every pip of Free Action you have unless you have enough (2 against low-level monsters, 3 against high-level monsters) to be completely safe.

In situations where no monsters are involved the calculations can also vary, but most commonly your saving throw needs to be higher than a random integer between 0 and 99.

3. Is there any use for the various statues of enemies I find? I know figurines give pets, but haven't found a use for statues. I thought maybe they'd give you full monster memory of that monster somehow, but haven't been able to test it yet.

There is currently no use for statues (other than selling if you play with selling on). The idea of a class or monster-race that would actually use statues for something has been suggested a couple times, but not yet implemented.

4. How much does slow monster slow the monster?

Slow Monster gives the binary -10 slow. It is possible for monsters to be incrementally slowed in other ways.

5. How does monster stunning work? Do they have increasing levels of severity like the player, or is it just duration based flat debuffs?

They have increasing levels of severity like the player. Stunning increases the monster's spell fail rates and decreases the monster's accuracy and damage output in melee.

6. For staves of confusing lights, do all the status effects have the same odds of being saved against, or are some easier than others? I've consistently gotten a power 160 or 200 staff to stun and terrify target creatures, but the slowing and stasis appears to happen much less, especially against tough enemies like archliches.

Yeah, they all have their own calculations. The stun from Confusing Lights, I think, is actually a direct stun with no save at all, it only checks stunning resistance (but monsters do get saves against most other sources of stunning).

7. How do I deal with monsters using dispel magic on me? Do I ever get a saving throw, or is it just their way of saying 'ha ha you suck now'

Psions can resist it, and the One with Magic demigod talent gives you a save against it; other than those, you'll just have to recast the buffs you really need after being dispelled.

8. How do vampiric weapons work, especially when they have other brands as well? Do I heal the full damage dealt from all blows, or just a portion?

It's only a portion, and it's limited, usually to 50 HP per turn. (Most other vampiric effects give full healing, but not weapons.) Vampiric brands generally work independently of other brands, though they're also just on/off, so having multiple things that all make your weapon vampiric doesn't make the vampirism any stronger.

[Saru]

Thanks for the quick reply and helpful answers @Sideways! I'd almost convinced myself that some of the higher leveled monsters were immune to slowing despite it not saying so in their description. Still, slow is better than I thought if it is a full -10, so I guess I'll keep spamming my confusing lights staves.

[Sideways]

Originally Posted by Saru

Thanks for the quick reply and helpful answers @Sideways! I'd almost convinced myself that some of the higher leveled monsters were immune to slowing despite it not saying so in their description. Still, slow is better than I thought if it is a full -10, so I guess I'll keep spamming my confusing lights staves.

Uniques are immune to slowing, also monsters who are immune to everything (babbles, spellwarp automatons), but no one else is.

[Saru]

I have a clevel 49 mage, Armageddon/Sorcery;

casting slow monster from the second sorcery book on a demilich (monster level 54 according to probing)

(54 vs 1d88 + 10), which means I should have a 50% chance of slowing the monster, but after 7+ castings the lich remains unslowed. Is there something else to the formula I'm not seeing, like a bonus to the monster's level? All the total has to do is be higher than the monster's level right?

I've accepted that I'm simply doing the math wrong somehow, but can't for the life of me think of what else to do.

[Sideways]

Originally Posted by Saru

I have a clevel 49 mage, Armageddon/Sorcery;

casting slow monster from the second sorcery book on a demilich (monster level 54 according to probing)

(54 vs 1d88 + 10), which means I should have a 50% chance of slowing the monster, but after 7+ castings the lich remains unslowed. Is there something else to the formula I'm not seeing, like a bonus to the monster's level? All the total has to do is be higher than the monster's level right?

I've accepted that I'm simply doing the math wrong somehow, but can't for the life of me think of what else to do.

That is actually a problem with the game itself, thanks for bringing this to my attention. The code used by this particular spell (and some other single-monster Slow Monster effects) computes a power (here 98) but then ignores it completely and uses the player's CL instead. I will need to fix that.

Mind you, during any given game, it will happen many times that 7 consecutive coin-flips all go wrong

[Saru]

Hmm, this bug doesn't affect the slow power from a stave of slowing or confusing lights though, right?

And I know that I could have just been really unlucky that time, but that was only the latest in a series of tests.

Thanks again for answering my questions and taking the time to look at this.

All the other power based spells, eg mass stasis are unaffected by this, correct?

[Sideways]

Originally Posted by Saru

Hmm, this bug doesn't affect the slow power from a stave of slowing or confusing lights though, right?

Right.

All the other power based spells, eg mass stasis are unaffected by this, correct?

In the development version, yes. There are slightly similar (though technically completely unrelated) issues with confusion in the last release version, although they generally don't make confusion unexpectedly weak the way slowness was for you. It is possible there's still some other oddball spell somewhere else with problems like this, but if so, it would be something much rarer and class- or realm-specific.

[Saru]

OK thanks for all the clarification! I'll post here if I have any more questions / weird interactions.

[Saru]

Traversing down Angband to grind for loot on the bottom few levels. DLevel 85 I get a random quest to kill 'Nodens, lord of the great abyss', or something like that. I've attempted to kill him 4 or 5 times, escaping only because of 0% fail teleport level. I managed to get probing off on him, and he looks and feels to be nearly impossible for my clevel 50 mage to even touch.

Globe of invulnerability is useless, since he has both psycho spear and dispel magic, and worse, he casts *extra intelligently* it feels like. Every haste I put up is instantly dispelled, as well as him favoring his nearly 500 dmg manastorm heavily. The most I've gotten him down to was 6 stars before having to bail. At this point I'm at a loss. Any tips? I don't want to intentionally fail the quest since that hurts fame, but if he's as impossible as I think he is then I may as well. Thanks in advance!