Fix wand hit calculation to use the Wands skill.

[mserajnik]

🍰 Pullrequest

Wand Shoot (spell 5019) deals spell damage but is, mechanically, a ranged weapon attack.

SpellCaster::SpellHitResult() dispatches the hit roll purely on DmgClass, and because the wand's DmgClass is SPELL_DAMAGE_CLASS_MAGIC it gets resolved by SpellCaster::MagicSpellHitChance(). That formula is keyed on the attacker/target level difference and never looks at the Wands weapon skill (228).

As a result, wand hit chance is completely independent of the Wands skill: a level 60 character with 1/300 skill has the exact same chance to hit as with 300/300. As the video evidence in #2361 shows, this is incorrect, at least for Classic.

Interestingly, VMaNGOS already treats wands as ranged for the crit roll via the SPELL_ATTR_EX3_NORMAL_RANGED_ATTACK attribute in Unit::IsSpellCrit() here:

core/src/game/Objects/Unit.cpp

Lines 5478 to 5482 in d41b70f

	// Wand shoot forced to use ranged crit
	uint32 const dmgClass = attackType == RANGED_ATTACK && spellProto->HasAttribute(SPELL_ATTR_EX3_NORMAL_RANGED_ATTACK) ?
	SPELL_DAMAGE_CLASS_RANGED
	:
	spellProto->DmgClass;

---

In CMaNGOS Classic, wand hit rate is resolved through the ranged weapon skill hit table (CalculateEffectiveMissChance() keyed on GetWeaponSkillValue(RANGED_ATTACK) for spells flagged SPELL_ATTR_EX3_NORMAL_RANGED_ATTACK).

This PR makes wands use ranged hit calculation, which aligns with CMaNGOS's approach:

In SpellCaster::SpellHitResult(), a SPELL_DAMAGE_CLASS_MAGIC spell flagged SPELL_ATTR_EX3_NORMAL_RANGED_ATTACK now goes to SpellCaster::MeleeSpellHitResult() here:

core/src/game/Objects/SpellCaster.cpp

Lines 219 to 227 in bfc51c2

	case SPELL_DAMAGE_CLASS_MAGIC:
	// Wands deal spell school damage but are ranged weapon attacks, so
	// their hit roll uses the ranged hit table, which is keyed on the
	// Wands skill, rather than the spell hit table, which is keyed on
	// level difference. This mirrors the wand crit handling in
	// Unit::IsSpellCrit.
	if (spell->HasAttribute(SPELL_ATTR_EX3_NORMAL_RANGED_ATTACK))
	return MeleeSpellHitResult(pVictim, spell, spellPtr);
	return MagicSpellHitResult(pVictim, spell, spellPtr);

It is then given the ranged attack type here:

core/src/game/Objects/SpellCaster.cpp

Lines 389 to 391 in bfc51c2

	// Wands use the ranged attack type.
	WeaponAttackType attType = (spell->DmgClass == SPELL_DAMAGE_CLASS_RANGED ||
	spell->HasAttribute(SPELL_ATTR_EX3_NORMAL_RANGED_ATTACK)) ? RANGED_ATTACK : BASE_ATTACK;

That path already derives the weapon skill from GetWeaponSkillValue() (which returns the Wands skill 228 for an equipped wand), so the hit roll now scales accordingly with the skill. Because wands use the ranged attack type, they still cannot be dodged, parried or blocked (the ranged path in MeleeSpellHitResult() returns before those rolls).

One side effect worth noting: a wand that fails its hit roll on the skill-based miss now reports SPELL_MISS_MISS (from the ranged hit table) instead of SPELL_MISS_RESIST, which also matches CMaNGOS. School-based resists still apply separately during damage calculation.

---

Disclaimer: I wasn't able to find any Vanilla sources, but the Classic video evidence (I think it's fair to assume Classic matches Vanilla here) and the fact that CMaNGOS already does this both point to it being more correct than the current behavior.

Also noteworthy, SPELL_ATTR_EX3_NORMAL_RANGED_ATTACK is only set on Shoot from 1.9.4.5086 onward, so this change only applies to those builds; this is the same as the existing wand crit handling, which is gated on the same flag. I wasn't able to find patch note evidence that this was changed, so I'm assuming this was an undocumented change back then. Maybe someone can confirm if this is true.

Proof

• See video evidence in 🐛 [Bug]Wand hit rate formula is wrong #2361

Issues

• Fixes 🐛 [Bug]Wand hit rate formula is wrong #2361

How2Test

• Create a Mage, Priest or Warlock character using a GM account
• .levelup 59 (use level 60 if you also want to observe the base miss chance at the 300 skill cap)
• .additem 5240 1 and equip the wand (Torchlight Wand)
• .go creature 40917 (teleports you to an isolated level 59-60 Frostsaber Stalker in Winterspring)
• Start wanding the Frostsaber Stalker and observe the hit chance rise as your Wands skill increases; level it all the way to 300 and confirm the base miss chance is correct. If the mob dies while attacking it, attack another one.
• Without this change, the hit chance does not change at all as the wand skill increases.

Todo / Checklist

• None