# Dwarf arts: Kanonenschuss and Mörsergranate

## Requests (2026-10-25 / 2026-10-26)

- Kanonenschuss (art 0x43f, `gui_spells_kanone`): "remove the knockback,
  instead it can be just a stun" (chosen: no push, only a stun); the range
  increased for the wider view; the stun particles not on targets that
  avoided the stun. The game's stun resistance stays (2026-10-26: "we dont
  ignore anything, the skill is fine for now").
- Mörsergranate (art 0x43e, `gui_spells_moerser`): "the radius of the
  explosion should increase every 5 skill levels".

## Measured

- The cannon's code is the combat move function `0x5145d0`, case 0x43f. Its
  ray: `cmp edi,19h` at `0x517389`, 25 steps of 40 = 1000 range. Hostile
  targets get `cEvent_creature` 5 from `0x51768d`.
- Stun chance `0x4fc810(level, creature)` = level × 5 / creature level × 100
  (`UI_STAT_STUNNCHANCE`). On a successful roll: `0x5936e0(MOTION_HIT_A 0xaf,
  3.0, 0.25)` at `0x517709` (pushes from `0x5176f8`), then the stun order
  `cEvent_creature` 3 with +0x14 = 100, sent by `call [eax+18h]` at
  `0x5177aa` (returns to `0x5177ad`).
- The stun *is* the knockback. `cCreature::ReceiveOrder` `0x52e400` case 3:
  first the resistance `vf24(0x50)` (`0x55d0a0`: flag +0x4f0 & 0x1000 resists
  2 in 3, effect 0x35d a percentage); otherwise push left +0x24d = 100, flag
  +0x200 |= 0x20000, attacker +0x259, ResetToIdle. `cCreature::Update` branch
  `0x594c82` moves a creature with that flag away from the attacker and lowers
  the push left by each step (`0x594deb`), measured about 100 units in 0.3 s;
  at 0 the flag is cleared.
- The impact effect `TYPE_FX_DWARF_SHOOT_IMPACT` (0x47f) is created on every
  hit target by `CreateAt` at `0x517855` (target in ebx), resisted or not.
- Mörsergranate: the grenade (type 0x3fa) lands and creates
  `TYPE_FX_GRENADEIMPACT` (0x3fc), which gathers its targets with
  `cObjectManager 0x5ff820` (called from `0x5ab400` at `0x5ab63d`): a creature
  is hit when its distance is below the impact's size (150, type table
  `0x428bb0`) plus its own type's size.

## The mod (`src/mods/dwarfarts.cpp`)

- The HIT_A motion is jumped over (`0x5176f8`: `jmp` past the call).
- The push step at `0x594deb` calls `PushStepThunk`: creatures the cannon
  stunned (order 3 from `0x5177ad`, kept with an end time) move by 0 and keep
  their push left above 0 for 1.5 s, so they stand still, then carry on.
- The impact effect is created only on targets in the stun state.
- The ray gets 45 steps (1800); confirmed to reach across the widened view.
- The impact's gather call gets a radius of size × (1 + 0.1 × (level / 5)),
  with the owner's Mörsergranate level (`game::ArtLevel`). The growth 0.1 per
  step is our choice; not yet seen in the game (Borf's level is 2).

## Mörsergranate impact marker (asked 2026-10-25, done 2026-10-26)

"Show exactly where the grenade will land and its explosion radius, a red
circle with low alpha on the ground."

Measured:
- The landing point is decided at launch (`0x5145d0` case 0x43e): the
  target's position, or, closer than 200, a point 200 from the dwarf with a
  +-15 jitter. It goes to the new grenade (type 0x3fa) in cEventFX 0x96,
  constructed at `0x5169fa` (`cEventFX::Construct` 0x41e0a0, thiscall, ret
  0x44: code, owner id, target id, position area / x / y / level, ...).
- The impact gathers its targets at exactly that point, on several frames.
  The grenade object stays about 30 s after the explosion.
- Ground -> screen: `0x622700` (world units -> world pixels, the isometric
  plane), then (pixel - camera +0x14/+0x18) / zoom +0xb60 + screen centre
  (floating texts 0x41e546). Checked with the hero: the screen centre.
- The world view draws the ground (`0x62d530`, ground quad list), then the
  objects.

Mod: the construct call notes grenade, owner, landing point and radius
(`ImpactRadius`, shared with the hit check); after `0x62d530` a disc (alpha
0x40) with a 2 px rim (alpha 0xa0) is drawn there, without depth test, until
the impact of that owner's grenade at that point gathers its targets.

Tooltip (2026-10-26, "the skills tooltip does not show the current radius"):
a game::Art tooltip filter adds "Explosionsradius: N" after the last value
line of each level section (current level, and the next level's in the skill
book), in that line's colour, from the same `ImpactRadiusAt(level)` as the
hit check and the marker.