Hit probability calculation

[Ycombinator]

I looked at the sources to find out the missile hit probability formula. Please, tell me if I got it right:

p_hit = 0.9 * (chance - 0.75 * AC_monster) / chance + 0.05,
where
chance = (character innate ability to shoot) + (total to-hit from character, launcher and ammo) * 3 - (distance to monster in tiles)

This is mostly archery vs magic question for me. Missiles often do more damage per hit than spells, but spells always hits the target and their fail probability is displayed in-game. Missile hit probability is unknown and can be quite low. So I think it can be interesting and useful to display missile hit probability against current target assuming its AC is already known to player.

What's your opinion? Is it worthwhile addition?

[Jungle_Boy]

This does not make sense. With this formula p_hit, which I believe is % chance to hit, is always at least .95 or 95%. I think the middle term should be (chance -0.75 * AC_Monster)/chance, giving a number less than one instead of greater and making increased monster armor result in a lower chance to hit rather than greater.

[Ycombinator]

This does not make sense. With this formula p_hit, which I believe is % chance to hit, is always at least .95 or 95%. I think the middle term should be (chance -0.75 * AC_Monster)/chance, giving a number less than one instead of greater and making increased monster armor result in a lower chance to hit rather than greater.

You're absolutely right. Edited.

[fizzix]

I'm not opposed to the idea, but I think you should follow the same approach for melee attacks also.

While we're on this topic. I'd like to see larger penalties for:

1. monster is far away
2. monster is in adjacent square
3. monster is unseen (invis, in darkened area, only known by telep/detection)
4. monster is partially obscured (no reverse LoS)
5. monster was not the desired target

forgive me if some are already covered (I know 1 is)

[buzzkill]

1. monster is far away
2. monster is in adjacent square
3. monster is unseen (invis, in darkened area, only known by telep/detection)
4. monster is partially obscured (no reverse LoS)
5. monster was not the desired target

I like all of this. It could also lead to interesting new (minor) abilities that could be added to launchers.

[Estie]

I'm not opposed to the idea, but I think you should follow the same approach for melee attacks also.

While we're on this topic. I'd like to see larger penalties for:

1. monster is far away
2. monster is in adjacent square
3. monster is unseen (invis, in darkened area, only known by telep/detection)
4. monster is partially obscured (no reverse LoS)
5. monster was not the desired target

forgive me if some are already covered (I know 1 is)

I like none of this. Imo, if archery is being toned down, the damage should be decreased instead of increasing the tedium of using shooter + ammo. It is already the most tedious to use, followed by magic and melee is simplest.

Edit: on second thought, point 2. might lead to something interesting.

[fizzix]

I increasing the tedium of using shooter + ammo.

A *lot* of the tedium can be overcome by macros. The fact that h has been changed to fire at nearest is a huge reduction in tedium. But yeah, archery without macros can be annoying.

[miyazaki]

I'm not opposed to the idea, but I think you should follow the same approach for melee attacks also.

While we're on this topic. I'd like to see larger penalties for:

1. monster is far away
2. monster is in adjacent square
3. monster is unseen (invis, in darkened area, only known by telep/detection)
4. monster is partially obscured (no reverse LoS)
5. monster was not the desired target

forgive me if some are already covered (I know 1 is)

I think these would mesh well with the nerfing of missile weapons. As for #2, you should not be able to shoot a monster in an adjacent square at all. (This was a feature in the combat of Ultima V, if anyone remembers.)

[Estie]

A *lot* of the tedium can be overcome by macros. The fact that h has been changed to fire at nearest is a huge reduction in tedium. But yeah, archery without macros can be annoying.

Of course. Id still put archery on number one, mostly because you have to manage missiles (picking them up again after battle, risk of having them destroyed while they are on the ground, need to find them in the first place etc.)

Generally, a character who doesnt hit is not fun to play. It is one thing to nerf wizards ranged to hit - "you are wizard, use your spells" - but certainly rangers, warriors and rogues should count archery to their preferred means of combat. With points 1. and 2. in place that would lead to a situation where they can only shoot effectively when the target is 2-3 squares away.
Adding the rest of the suggestions could quickly lead to a situation where I, as a ranger, wouldnt bother with missiles at all and just use melee by default.