Warcraft III Attack Damage

See Unit Stat Modifiers for the shared ledger and damage-entry contracts used by attack, armor, spell, and direct damage effects.

Contract

OpenRealm keeps normal WC3 attack damage in three layers:

unitAttack_t.damageBase + dice describe the permanent displayed range.
unitAttack_t.temporaryDamageBonus is added after the dice roll and is shown as a green/red +N/-N suffix.
G_AttackDamage() applies the target-facing attack-type/defense-type multiplier and numeric armor.

The ordinary Attack 1 path is:

unit object data
  -> permanent runtime attack mutations (`ratx`, `ratd`, Hero primary attribute)
  -> roll `damageBase + NdS + temporaryDamageBonus`
  -> attack-type x defense-type multiplier
  -> numeric armor
  -> `T_Damage`

Melee resolves the target-facing stages at the damage point. Missile attacks roll damage and snapshot the selected attack type at launch, then apply that type against the target's current defense and armor at impact. Thus in-flight target defense/armor changes affect the hit while a target morph or later attacker order cannot replace the launched attack slot. Before that normal impact path, a basic missile may be consumed or retargeted by the Defend projectile reaction. Spell missiles provide their own currentmove/endfunc and do not enter this physical-attack/Defend-missile branch.

WPN_ARTILLERY shares the physical projectile launch path instead of falling through the melee resolver. The unit-level authored minRange is a real dead zone: a mobile attacker backs away until the target is outside it, while a holding/immobile attacker cannot fire. At the attack damage point an artillery unit target is converted to a fixed point, matching Warsmash's CBehaviorAttack: the missile flies to that snapshot even if the original unit moves afterward. The projectile snapshots its attack type, splash bands, factors, and matching splashTargs mask at launch, so later orders or target selection cannot change impact behavior. Impact then applies those values around the fixed point. If the original unit target is still inside the blast, it retains the ordinary primary-hit pipeline; secondary victims (and all victims of Attack Ground, which has no primary unit) receive physical splash damage without duplicating primary-only orb/lifesteal/cleave behavior. CmdAttackGround uses the same point-target projectile/splash path and is exposed only for the implemented WPN_ARTILLERY class. Attack Ground approach/retreat steps consult Move-owned S_UnitCanTranslate (immobile, Cyclone, Roots, Ensnare, Purge pause) every tick: a locked unit holds its firing point without translating or cancelling, and still fires in-range points.

T_Damage() ignores targets whose life is already zero, and unit_die() is a one-shot transition once SVF_DEADMONSTER is set. This matters for simultaneous or near-simultaneous missile impacts: only the first lethal hit may publish WC3 death events, so map-authored death/loot triggers cannot run twice for the same corpse.

Defend projectile reaction

An active Adef target may react to a basic ranged attack before the ordinary hit resolves. Data F is a 0..100 chance and is gated by Misc.DefendDeflection. Piercing uses Data G as the successful-deflection damage-taken factor; Magic/Spells uses Data H. A unit-source success retargets the same missile edict to its original owner and sets projectile_reflected, preventing a second return. A building-source success consumes the missile rather than reflecting it into the structure. The flag and projectile target/owner references cross save/load, so a return flight remains semantically the same after loading.

Runtime Attack Fields

edict_t.attack1 and attack2 are mutable copies of UnitWeapons.slk data. Target validation checks both authored target masks without changing either profile. Attack timing, projectile setup, and damage select the compatible profile from the current target, leaving both authored runtime copies in their original slots. Candidate scans and repeated target validation are read-only, so their traversal order cannot change the active weapon.

For each unitAttack_t:

damageBase: permanent base used by the HUD range and roll.
numberOfDice, sidesPerDie: NdS random component.
permanentDamageBonus: permanent modifier ledger used to survive Hero stat recomputation (for example ratx).
temporaryDamageBonus: item/temporary modifier added to each roll but not folded into the base range.
cooldown, damagePoint, backswingPoint: attack-cycle timing.
range, rangeBuffer: true weapon range and cooldown-only movement hysteresis.
artillery splash metadata (Farea/Harea/Qarea, Hfact/Qfact, splashTargs) is consumed by the generic WPN_ARTILLERY impact path; bounce/line/missile-splash weapon classes remain separate gaps.

Chase range and attack timing

Direct Attack continues to use the compatible runtime Attack 1/Attack 2 profile selected for the current target. The weapon cooldown starts with the swing; while it remains active, that selected profile's RngBuff1/RngBuff2 runtime copy (rangeBuffer) extends only the range at which the attacker may remain stationary while moving or recovering. The windup still rechecks true range at damage point before it commits a hit/projectile. Cooldown state and its remaining timer survive a chase transition, including a canceled windup; the attacker can stop again inside buffered range, and when cooldown expires it rechecks unbuffered range before beginning another swing. The later attack-animation end callback preserves the swing-start deadline instead of restarting cooldown - damagePoint, so a long animation tail does not extend either the cooldown or its range buffer. Thus RngBuff cannot become extra firing range. Ensnare's forced melee-range rule remains authoritative and does not receive the normal range buffer.

Before melee damage or a projectile is committed at damage point, the target is rechecked against the true, unbuffered weapon range and minimum range. A target that escapes during windup cancels the pending launch and returns the attacker to chase; a projectile already launched remains owned by the projectile system.

Runtime attacks now retain the authored backSw1/backSw2 value as backswingPoint. Direct Attack and Attack Ground post-damage recovery wait for whichever gate is longer: remaining weapon cooldown (cooldown - damagePoint) or authored backswing. This prevents custom data with backswing longer than the remaining cooldown from starting the next swing early. Animation presentation is still driven by the existing model-sequence state machine; this change does not introduce a separate global surround or combat-animation scheduler. Attack profile timing/range fields and the active cooldown marker and timer are included in game saves.

The displayed permanent range is:

min = max(0, damageBase + numberOfDice)
max = max(0, damageBase + numberOfDice * sidesPerDie)

A temporary bonus is rendered separately, for example 12 - 18 +3.

Damage Roll

skills/s_attack.c:ai_rolldamage1() performs one RNG draw per die:

raw = damageBase
    + sum(random(1..sidesPerDie))
    + temporaryDamageBonus

Malformed zero-sided dice contribute +1 rather than taking modulo zero, matching the current Warsmash edge behavior.

OpenRealm still uses the process C rand() stream. It does not yet have Warsmash's dedicated seeded simulation RNG contract for attack rolls.

Hit resolution order

S_ResolveAttackHit runs Evasion first, then Curse miss, damage bonuses, and Bash. Evasion (S_EvasionRoll) and Bash resolve the owned alias plus rank through S_ResolveAbilityAlias (native abilList, runtime-added honoring removals, ranked hero slots, authored code= mapping) and read chance/bonus from the alias row — so creep ACes/ACev (100% evade) and ACbh work instead of only base AEev/AHbh. Critical Strike keeps its explicit ACct fallback. Tests use 0/100 chances; low-percentage rolls are not asserted probabilistically.

S_AttackHitAllowed(attacker, primary, victim) applies the Ethereal gate to primary hits, Moon Glaive bounce candidates, Cleave victims, and Human weapon splash victims. Secondary effects carry the weapon selected for the primary target; do not select a different magic weapon for an Ethereal secondary victim. These effects already receive mitigated primary damage, so calling G_AttackDamage again would apply armor/type scaling twice. Keep the gate out of untyped T_Damage, which also serves direct/scripted damage. Artillery splash already resolves each victim through attack_damage_type with its snapshotted attack type. wc3_spell.ethereal_secondary_targets_reject_physical_attacks covers all three secondary paths, status removal restoring physical damage, and a magic primary weapon accepting Ethereal victims. It runs with both Classic and TFT fixtures.

Gameplay Constants

InitConstants() loads combat values from the active Misc data cache. war3mapMisc.txt is loaded after stock Misc files and can override them.

Relevant fields:

DamageBonusNormal
DamageBonusPierce
DamageBonusSiege
DamageBonusChaos
DamageBonusMagic
DamageBonusHero
DamageBonusSpells (if absent, copy the active Magic row as Warsmash does)
DefenseArmor
StrAttackBonus
AgiDefenseBonus
AgiAttackSpeedBonus
DefendDeflection

The defense-column order is:

small, medium, large, fort, normal, hero, divine, none

Stock fallback values are retained only for missing data/bootstrap tests. In particular, ordinary attack classes deal 0.05x to Divine while Chaos deals 1.00x.

Numeric Armor

Let A be G_UnitArmorValue(target) and K be Misc.DefenseArmor (stock fallback 0.06).

For A >= 0:

multiplier = 1 / (1 + K*A)

For A < 0:

multiplier = 2 - (1 - K)^(-A)

G_AttackDamage() applies:

final = raw * DamageBonus[attackType][defenseType] * armorMultiplier

and preserves OpenRealm's existing minimum-one physical-hit rule.

armor_value is the derived/base armor plus tracked persistent modifiers. permanent_armor_bonus (research) and temporary_armor_bonus (items) are kept separately so G_RecomputeHeroStats() cannot erase them when Agility changes. G_UnitArmorValue() then layers timed status armor such as Bdef on top.

Hero Attack Math

For heroes, G_RecomputeHeroStats() applies the active Misc.StrAttackBonus to the current primary attribute (STR, AGI, or INT) and adds permanentDamageBonus when rebuilding each runtime attack.

Current limitation: OpenRealm's doodadHero_t stores only total STR/AGI/INT, not Warsmash's separate base and bonus attributes. Therefore primary-attribute item/stat bonuses are still folded into the permanent damage range rather than displayed as a separate green primary-attribute damage bonus. AIat attack bonuses are separated correctly.

Agility attack timing uses:

totalBonus = agility * Misc.AgiAttackSpeedBonus
clampedBonus = clamp(totalBonus, -0.90, +4.00)
divisor = 1 + clampedBonus

Both damage point and cooldown recovery are divided by that divisor. The same shared accumulator also includes implemented status modifiers such as Bloodlust, Frenzy, Unholy Frenzy, Cripple, Slow Poison, and Footman Defend Data D before the Warcraft [-90%, +400%] clamp is applied.

Upgrade Effects

The generic research dispatcher implements:

ratx: permanent flat attack damage using base + mod*(level-1) and applying only the old/new delta.
ratd: attack dice using the same level-value/delta rule.
rarm: armor using the unit type's armorPerUpgrade, tracked in permanent_armor_bonus.

These affect existing owned units and newly spawned units that inherit already-researched player tech.

Item Attack/Armor Modifiers

AIat changes temporaryDamageBonus rather than damageBase. This prevents later Hero stat recomputation from erasing the item bonus and makes the HUD show the modifier separately.

AIde changes both temporary_armor_bonus and the current armor_value, so later Hero Agility recomputation preserves the item armor modifier.

Missile Presentation

Ranged Attack 1 missiles remain ordinary server entities with MOVETYPE_FLYMISSILE; the renderer does not own a parallel WC3-only projectile object. G_StartProjectilePresentation() therefore initializes presentation state when the missile is spawned: the entity is non-selectable, does not cast a unit shadow, and selects the projectile model's authored Stand sequence, falling back to Birth only when no Stand sequence exists. SV_Physics_Toss() advances that sequence while the missile is in flight. Ordinary missiles continue to update yaw from their current homing direction every simulation frame; artillery missiles instead carry AI_PROJECTILE_FIXED_TARGET plus the launch-time point in channel.origin, so they no longer depend on a moving/freed target entity. The existing snapshot model/frame/angle fields remain sufficient for presentation, and the fixed point rides in already-persisted edict state rather than adding a client-only projectile object. Attack and spell missiles also inherit the firing unit's existing s.player, allowing the client MDX renderer to resolve replaceable team-colour textures from the correct source player just as it does for ordinary entities.

This is important for Warcraft missile MDX files whose visible geosets/emitters begin in a sequence interval above frame zero. Merely assigning the registered missile model with frame == 0 can leave a valid projectile simulation entity visually empty. Spell missiles using the same MOVETYPE_FLYMISSILE path receive the same initialization rather than maintaining a second animation policy.

The current implementation still moves the simulation entity on a straight three-dimensional line toward the target. Authored projectile arc/pitch and a post-impact Death presentation are separate fidelity gaps; they are not approximated here because the current entityState_t Warcraft path has only yaw orientation and frees basic attack missiles immediately when damage resolves.

Weapon Target Legality And Acquisition

Attack 1 target legality is owned by skills/s_attack.c, not by the generic AI scanner. UnitWeapons.slk targs1 (or map-object ua1g) is decoded to the runtime attack1.targetsAllowed Warcraft targetflag mask. G_TargetFlagForType() is the shared TARGTYPE -> targetflag conversion used by ordinary units and destructables.

S_AttackCanTarget() applies that authored mask to explicit Attack orders and every later attack recheck. For ordinary units, the target's UnitData.targetType supplies the ground/air/structure/etc. category; destructables continue through G_DestructableCanBeAttackedBy(). This keeps target legality in the Attack ability instead of teaching generic AI about Spirit Towers, Burrows, or other particular unit rawcodes.

Minimum attack range is checked alongside maximum range. It comes from UnitWeapons.minRange (uamn) rather than a Meat-Wagon rawcode special case. A mobile unit already ordered to attack a target inside that dead zone steps directly away from the target until it can fire; Hold Position and AI_IMMOBILE units drop the impossible attack instead.

Automatic acquisition adds one policy on top through S_AttackCanAutoAcquire():

mobile attackers may acquire a legal target anywhere inside their authored acquisition range and chase it normally;
structures are ordinary candidates when their weapon target mask allows structure; there is no global AI exclusion for buildings;
AI_IMMOBILE attackers only auto-acquire targets already inside their effective Attack 1 range, because they cannot chase an acquisition-range target; building-target range uses the target pathing footprint when available, matching normal attack-range checks.

This is important for defensive buildings whose acquisition range may exceed weapon range: an idle tower must not enter an attack behavior for a target it cannot approach. If an explicit or previously valid attack target is out of range while AI_IMMOBILE, ai_attack_walk() finishes that attack behavior instead of leaving the structure stuck in a non-moving walk state. This matches Warsmash's movement-disabled ranged behavior, which drops an out-of-range attack when no move behavior exists.

Relevant regression coverage is in games/warcraft-3/game/tests/t_combat.c: ground/air mask rejection, nearest-target filtering, structure acquisition, immobile out-of-range acquisition, explicit immobile out-of-range attack cancellation, artillery ranged-state selection, minimum-range retreat, authored three-band artillery splash, target-position snapshotting at the damage point, and explicit Attack Ground launch.

Destructable Attack Targeting

Destructables use their targType/Targeted As category together with the attacking unit's targs1 target list. Warcraft stores UnitWeapons.slk targs1/targs2 as comma-separated names such as ground,structure,debris,item,ward; OpenRealm decodes those names to the targetflag mask (tree=64, wall=128, debris=256, decoration=512, bridge=1024) before copying Attack 1 into runtime state. Map object-data ua1g/ua2g overrides remain numeric masks.

Smart/right-click turns ordinary debris into an implicit attack, which keeps breakable crates convenient. Trees keep worker harvesting precedence and do not Smart-attack, but the explicit Attack command may attack a live tree even when the standard weapon target list omits tree (as retail UnitWeapons data commonly does). Wall/bridge/decoration classes still require explicit Attack and the corresponding weapon target bit. This prevents right-click from attacking every selectable destructable merely because it has life.

Relevant coverage is in games/warcraft-3/game/tests/t_destructable.c.

Known Gaps

The current implementation intentionally does not invent the larger Warsmash combat-listener architecture. Remaining work includes:

attacker pre-damage listeners (critical strike, bash, Wind Walk, attack replacement/orbs);
low-ground miss and target evasion;
target damage-taken and final-damage listeners;
generic distinction between attack type and damage type / numeric-armor bypass;
MSPLASH, MBOUNCE, MLINE/ALINE damage behavior; ARTILLERY now has projectile/min-range/three-band splash, damage-point target snapshotting, and Attack Ground gameplay. ALINE still needs its distinct line-damage implementation before sharing the Attack Ground command;
both Attack 1 and Attack 2 target masks participate in ordinary unit target validation; the selected compatible profile drives the shared attack path. Full retail weapon-selection priorities and special weapon classes remain separate gaps;
separate Hero base-vs-bonus attributes for Warsmash-exact green primary-stat damage;
seeded combat RNG independent from unrelated rand() consumers;
non-Agility attack-speed buffs/debuffs.

Attack-target validation takes both the attacker and target, including the animationless building recovery checks used by Orc Burrows. Those recovery checks apply the same weapon target mask as initial attack orders and attack windup validation.

Verification

Relevant source/tests:

games/warcraft-3/game/skills/s_attack.c
games/warcraft-3/game/g_phys.c
games/warcraft-3/game/m_unit.c
games/warcraft-3/game/g_building.c
games/warcraft-3/game/skills/s_item_stats.c
games/warcraft-3/game/tests/t_combat.c
games/warcraft-3/game/tests/t_building.c

The combat tests cover representative type multipliers, Divine, data-driven constants, positive/negative armor, Hero modifier preservation, and the attack-speed cap. Research tests cover ratx level-delta semantics.