Fix Multiple Shot ammunition branching and Missiles.txt 684-row parity (Closes #562, #568, #571, #572, #574, #576)

src/client/session/online-session.ts

@@ -1141,20 +1141,18 @@ export class OnlineSession {
     if (this.gameAdapter && this.gameAdapter.state !== 'closed') {
       try {
         this.gameAdapter.send(cmd)
-        this.world.noteOutgoingCommand(cmd, nowMs)
-        if (this.world.selfId !== 0) {
-          const selfUnit = this.world.getUnit('player', this.world.selfId)
-          if (selfUnit?.castState && !this.predictor.getSnapshot().moving) {
-            this.predictor.setTargetDirection(selfUnit.targetDirection, false)
-          }
-        }
       } catch (err) {
         const msg = err instanceof Error ? err.message : String(err)
         this.handleUnexpectedDisconnect(`Failed to send command ${cmd.type}: ${msg}`, 'error', true)
         return
       }
-    } else {
+    }
-      this.world.noteOutgoingCommand(cmd, nowMs)
+    this.world.noteOutgoingCommand(cmd, nowMs)
+    if (this.world.selfId !== 0) {
+      const selfUnit = this.world.getUnit('player', this.world.selfId)
+      if (selfUnit?.castState && !this.predictor.getSnapshot().moving) {
+        this.predictor.setTargetDirection(selfUnit.targetDirection, false)
+      }
     }
     if (
       cmd.type === 'SkillAt' ||

src/client/world/client-world.ts

@@ -210,6 +210,13 @@ const BUTTON_ACTION_OPEN_STASH = 0x10
 /** Largest 1.13c stat id: stat ids are 9 bits wide in the stat bitstream (ItemStatCost.txt). */
 const MAX_D2_STAT_ID = 0x1ff
 
+/** 1.13c crossbow item codes (normal, exceptional, elite). */
+const CROSSBOW_ITEM_CODES = new Set([
+  'lxb', 'mxb', 'hxb', 'rxb',
+  '8lx', '8mx', '8hx', '8rx',
+  '6lx', '6mx', '6hx', '6rx',
+])
+
 /** 1.13c physical/weapon attack skill IDs that use attack animation mode (`A1`) instead of spellcast (`SC`). */
 const PHYSICAL_ATTACK_SKILL_IDS = new Set([
   0, 2, 6, 7, 10, 11, 12, 16, 19, 20, 21, 22, 24, 26, 27, 31, 96, 97, 106, 107, 116, 126, 133, 139,
@@ -529,7 +536,7 @@ export class ClientWorld {
     const defaultMaxTicks =
       !loopAnim && data.vel === 0
         ? Math.max(1, Math.ceil((totalFrames * 16) / animSpeed))
-        : Math.max(1, (data.range || 20) + Math.max(0, level - 1) * (data.levRange ?? 0))
+        : Math.max(1, data.range + Math.max(0, level - 1) * (data.levRange ?? 0))
     const maxTicks = opts?.maxTicks ?? defaultMaxTicks
 
     const unit = new ClientUnit({
@@ -577,6 +584,35 @@ export class ClientWorld {
     return unit
   }
 
+  private isCrossbowEquipped(caster: ClientUnit): boolean {
+    if (caster.unitType === 'player') {
+      const isSelf = caster.id === this.selfId || this.selfId === 0
+      if (isSelf) {
+        const eqWeapon =
+          this._containers.equipmentBySlot.get(4) ?? this._containers.equipmentBySlot.get(5)
+        if (eqWeapon) {
+          const code = (eqWeapon.code ?? '').trim().toLowerCase()
+          if (CROSSBOW_ITEM_CODES.has(code)) return true
+          const rawName = (eqWeapon as any).name
+          if (typeof rawName === 'string') {
+            const name = rawName.toLowerCase()
+            if (
+              name.includes('crossbow') ||
+              name.includes('arbalest') ||
+              name.includes('ballista') ||
+              name.includes('chu-ko-nu')
+            ) {
+              return true
+            }
+          }
+        }
+      }
+      const weaponType = (caster as any).equippedWeaponType ?? (caster as any).weaponItemType
+      if (typeof weaponType === 'string' && weaponType.toLowerCase() === 'crossbow') return true
+    }
+    return false
+  }
+
   /**
    * Spawns canonical 1.13c projectile/ground/radial/spiral/emitter missiles for a skill cast.
    */
@@ -612,12 +648,17 @@ export class ClientWorld {
 
     // 2. Multi-projectile fan spells: Charged Bolt (38), Teeth (67), Multiple Shot (12)
     if (skillId === 38 || skillId === 67 || skillId === 12) {
-      const missileKey =
+      let missileKey =
         skillId === 38 ? 'chargedbolt' : skillId === 67 ? 'teeth' : 'multipleshotarrow'
-      const count =
+      let count = 2
-        skillId === 38
+      if (skillId === 38) {
-          ? Math.min(24, 2 + Math.max(1, skillLevel))
+        count = Math.min(24, 2 + Math.max(1, skillLevel))
-          : Math.min(24, Math.max(2, 1 + Math.max(1, skillLevel)))
+      } else if (skillId === 67) {
+        count = Math.min(24, 1 + Math.max(1, skillLevel))
+      } else if (skillId === 12) {
+        count = Math.min(24, 2 + Math.max(1, skillLevel))
+        missileKey = this.isCrossbowEquipped(caster) ? 'multipleshotbolt' : 'multipleshotarrow'
+      }
       const totalSpread = Math.min(Math.PI * 0.65, 0.14 * Math.max(1, count - 1))
       for (let i = 0; i < count; i++) {
         const offset = count === 1 ? 0 : -totalSpread / 2 + (totalSpread * i) / (count - 1)
@@ -844,8 +885,6 @@ export class ClientWorld {
     spawnVisuals = true,
     nowMs?: number,
   ): void {
-    unit.targetX = targetX
-    unit.targetY = targetY
     unit.lastSkillId = skillId
     unit.moveMode = 'stop'
     // Turn toward the cast/attack target via D2Common.#10425 (bInstant = 0); 25Hz tick steps
@@ -870,6 +909,18 @@ export class ClientWorld {
       effRate = animParams.effRate
       stepSpeed256 = animParams.stepSpeed256
       durationMs = animParams.durationMs
+    } else if (unit.unitType === 'monster') {
+      if (unit.totalFrames && unit.totalFrames > 0) {
+        frames = unit.totalFrames
+      }
+      if (unit.animStepSpeed256 && unit.animStepSpeed256 > 0) {
+        stepSpeed256 = unit.animStepSpeed256
+        baseSpeed = stepSpeed256
+      } else if (unit.animSpeed && unit.animSpeed > 0) {
+        baseSpeed = Math.round((unit.animSpeed / 16) * 256)
+        stepSpeed256 = baseSpeed
+      }
+      durationMs = computeOneShotDurationMs(frames, stepSpeed256)
     }
 
     const castState: UnitCastState = {
@@ -1217,7 +1268,7 @@ export class ClientWorld {
     hitY: number,
     isWallHit: boolean,
   ): void {
-    const expKey =
+    let expKey =
       missile.explosionMissile ||
       (!isWallHit &&
       (missile.missileKey === 'lightning' ||
@@ -1227,6 +1278,12 @@ export class ClientWorld {
         ? 'lightninghit'
         : '')
 
+    if (expKey === 'freezingarrowexp1') {
+      expKey = 'freezeexplode'
+    } else if (expKey === 'freezingarrowexp2') {
+      expKey = 'glacialspikeejecta'
+    }
+
     if (expKey) {
       const exp = this.spawnMissileByKey(expKey, hitX, hitY, hitX, hitY, {
         ownerType: missile.ownerType,
@@ -1592,9 +1649,8 @@ export class ClientWorld {
     if (!Number.isFinite(dtMs)) {
       throw new RangeError(`dtMs must be a finite number, got ${String(dtMs)}`)
     }
-    const safeDt = Math.max(0, dtMs)
+    const safeDt = Math.min(200, Math.max(0, dtMs))
-    const cappedDt = Math.min(200, safeDt)
+    this._tickAccumulatorMs = Math.min(200, this._tickAccumulatorMs + safeDt)
-    this._tickAccumulatorMs += cappedDt
     this._simTimeMs += safeDt
 
     this.expireCastStates(nowMs, safeDt)
@@ -2143,9 +2199,12 @@ export class ClientWorld {
             unit.animStepSpeed256 = speedInfo.stepSpeed256
             unit.animEffRate = speedInfo.effRate
           } else if (unit.unitType === 'monster' && resolvedMode === 3) {
-            unit.modeDurationMs = 240
+            const ghFrames = unit.totalFrames && unit.totalFrames > 0 ? unit.totalFrames : 8
-            unit.modeUntilMs = now + 240
+            const ghSpeed = unit.animStepSpeed256 && unit.animStepSpeed256 > 0 ? unit.animStepSpeed256 : 256
-            unit.animStepSpeed256 = undefined
+            const ghDuration = computeOneShotDurationMs(ghFrames, ghSpeed)
+            unit.modeDurationMs = ghDuration
+            unit.modeUntilMs = now + ghDuration
+            unit.animStepSpeed256 = ghSpeed
             unit.animEffRate = undefined
           } else {
             unit.modeDurationMs = undefined
@@ -2232,7 +2291,10 @@ export class ClientWorld {
         // 0x73 CreateMissile: caster.unitType === 3 ('missile')
         if (unitTypeFromId(casterType) === 'missile') {
           const missileClassId = skillId
-          const missileKey = MISSILE_CLASS_ID_TO_KEY[missileClassId] ?? 'arrow'
+          const missileKey = MISSILE_CLASS_ID_TO_KEY[missileClassId]
+          if (!missileKey) {
+            throw new Error(`Unknown missile classId ${missileClassId} in Missiles.txt`)
+          }
           const ownerType = ev.owner ? unitTypeFromId(ev.owner.unitType) : 'player'
           const ownerId = ev.owner?.id ?? 0
           const ownerUnit = ev.owner ? this.getUnit(ev.owner.unitType, ev.owner.id) : undefined
@@ -2292,12 +2354,11 @@ export class ClientWorld {
           (unit.id === this.selfId || this.selfId === 0) &&
           skillId === this._lastLocalCastSkillId &&
           timeSinceLocalCast >= 0 &&
-          timeSinceLocalCast <= 500
+          timeSinceLocalCast <= 1000
         if (isSelfEcho) {
           this._lastLocalCastSkillId = -1
           if (unit.castState && unit.castState.skillId === skillId && now < unit.castState.untilMs) {
-            unit.targetX = targetX
+            unit.faceToward(targetX, targetY, false)
-            unit.targetY = targetY
           } else {
             this.applySkillCastToUnit(unit, skillId, targetX, targetY, level, false, nowMs)
           }

src/server/engine/combat-pipeline.ts

@@ -177,7 +177,9 @@ export function computeToHitChance(params: {
   const alvl = Math.max(1, params.attackerLvl)
   const dlvl = Math.max(1, params.defenderLvl)
 
-  const raw = Math.trunc((2 * effAr * 100 * alvl) / (Math.max(1, effAr + effDef) * (alvl + dlvl)))
+  const divisor = effAr + effDef
+  const toHitFactor = divisor > 0 ? Math.trunc((100 * effAr) / divisor) : 100
+  const raw = Math.trunc((2 * alvl * toHitFactor) / (alvl + dlvl))
   return Math.max(5, Math.min(95, raw))
 }
 

tests/client/client-world.test.ts

@@ -879,7 +879,7 @@ describe('ClientWorld authoritative state mirror', () => {
     )
     expect(subBolts.length).toBeGreaterThanOrEqual(4)
 
-    // 6. Multiple Shot (skill 12, level 5 -> 6 multipleshotarrow missiles in a fan, classId=213)
+    // 6. Multiple Shot (skill 12, level 5 -> 7 multipleshotarrow missiles in a fan per 1.13c calc1 min(24, 2 + slvl), classId=213)
     const msWorld = new ClientWorld()
     msWorld.apply({
       type: 'UnitAssign',
@@ -897,7 +897,7 @@ describe('ClientWorld authoritative state mirror', () => {
     const multiShotArrows = Array.from(msWorld.units.values()).filter(
       u => u.unitType === 'missile' && u.missileKey === 'multipleshotarrow',
     )
-    expect(multiShotArrows).toHaveLength(6)
+    expect(multiShotArrows).toHaveLength(7)
     expect(multiShotArrows.every(m => m.classId === 213)).toBe(true)
 
     // 7. Challenge 3: spawnMissileByKey('arrow') without opts.classId preserves classId === 0