fix(Scripts/Ulduar): Vehicle scaling formula (#26239)

src/server/game/Entities/Player/Player.cpp

@@ -15965,6 +15965,24 @@ void Player::_LoadRandomBGStatus(PreparedQueryResult result)
         m_IsBGRandomWinner = true;
 }
 
+float Player::GetTotalItemLevel() const
+{
+    float sum = 0;
+    uint8 level = GetLevel();
+
+    for (uint8 i = EQUIPMENT_SLOT_START; i < EQUIPMENT_SLOT_END; ++i)
+    {
+        // don't check tabard, ranged, offhand or shirt
+        if (i == EQUIPMENT_SLOT_TABARD || i == EQUIPMENT_SLOT_RANGED || i == EQUIPMENT_SLOT_OFFHAND || i == EQUIPMENT_SLOT_BODY)
+            continue;
+
+        if (m_items[i] && m_items[i]->GetTemplate())
+            sum += m_items[i]->GetTemplate()->GetItemLevelIncludingQuality(level);
+    }
+
+    return sum;
+}
+
 float Player::GetAverageItemLevel()
 {
     float sum = 0;

src/server/game/Entities/Player/Player.h

@@ -2598,6 +2598,7 @@ public:
     Spell* m_spellModTakingSpell;
 
     float GetAverageItemLevel();
+    [[nodiscard]] float GetTotalItemLevel() const;
     float GetAverageItemLevelForDF();
     bool isDebugAreaTriggers;
 

src/server/scripts/Spells/spell_generic.cpp

@@ -2563,28 +2563,28 @@ class spell_gen_vehicle_scaling_aura: public AuraScript
 
     void CalculateAmount(AuraEffect const* /*aurEff*/, int32& amount, bool& /*canBeRecalculated*/)
     {
-        Unit* caster = GetCaster();
+        Player* player = GetCaster()->ToPlayer();
-        float factor;
-        uint16 baseItemLevel;
 
         /// @todo Reserach coeffs for different vehicles
         switch (GetId())
         {
             case SPELL_GEAR_SCALING:
-                factor = 1.0f;
+            {
-                baseItemLevel = 205;
+                float avgILvl = player->GetAverageItemLevel();
+                if (avgILvl < 205.0f)
+                    return;
+
+                amount = static_cast<int32>(avgILvl - 205.0f);
                 break;
+            }
             default:
-                factor = 1.0f;
+            {
-                baseItemLevel = 170;
+                float totalILvl = player->GetTotalItemLevel();
+                float result = (totalILvl - 2500.0f) / 5.0f / 100.0f;
+                amount = static_cast<int32>(std::max(0.1f, result));
                 break;
+            }
         }
-
-        float avgILvl = caster->ToPlayer()->GetAverageItemLevel();
-        if (avgILvl < baseItemLevel)
-            return;                     /// @todo Research possibility of scaling down
-
-        amount = uint16((avgILvl - baseItemLevel) * factor);
     }
 
     void Register() override

src/test/server/game/Spells/VehicleScalingUlduarTest.cpp

@@ -0,0 +1,244 @@
+/*
+ * This file is part of the AzerothCore Project. See AUTHORS file for Copyright information
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * @file VehicleScalingUlduarTest.cpp
+ * @brief Tests for Ulduar vehicle gear scaling formula
+ *
+ * Formula (from spell_gen_vehicle_scaling_aura in spell_generic.cpp):
+ *
+ *   result = (totalAdjustedILvl - 2500) / 500
+ *   amount = int32(max(0.1f, result))
+ *
+ * Where:
+ *   totalAdjustedILvl = sum of GetItemLevelIncludingQuality across 15 equipped slots
+ *                       (excludes offhand, ranged, shirt, tabard)
+ *   GetItemLevelIncludingQuality bakes in quality penalty: -26 for uncommon/below,
+ *   -13 for rare; heirloom items use pLevel * 2.33f instead of base ItemLevel.
+ *   floor: 0.1 when totalAdjustedILvl < 2500
+ *
+ * Source data: Google Sheets "Ulduar Vehicle Scaling"
+ * Vehicle: Salvaged Demolisher (entry 33109)
+ */
+
+#include "gtest/gtest.h"
+
+#include <algorithm>
+#include <cmath>
+#include <cstdint>
+
+namespace
+{
+    /// Mirrors the Ulduar vehicle scaling formula from spell_gen_vehicle_scaling_aura::CalculateAmount.
+    /// totalAdjustedILvl is the sum of GetItemLevelIncludingQuality across equipped slots
+    /// (quality penalty is already baked into each item's value).
+    /// Computes the raw float result before int32 truncation.
+    float CalcUlduarVehicleScale(float totalAdjustedILvl)
+    {
+        float const baseILvl = 2500.0f;
+        float result = (totalAdjustedILvl - baseILvl) / 5.0f / 100.0f;
+        return std::max(0.1f, result);
+    }
+
+    /// Mirrors the final int32 amount stored on the aura effect.
+    int32_t CalcUlduarVehicleScaleAmount(float totalAdjustedILvl)
+    {
+        return static_cast<int32_t>(CalcUlduarVehicleScale(totalAdjustedILvl));
+    }
+}
+
+// =============================================================================
+// Formula structure: result = (totalAdjustedILvl - 2500) / 500
+// =============================================================================
+
+class UlduarVehicleScaleTest : public ::testing::Test {};
+
+TEST_F(UlduarVehicleScaleTest, BaselineNoGear)
+{
+    // totalILvl = 2500 (e.g. 15 items at avg 166.67)
+    // Formula gives 0. Floor at 0.1 -> 0.1, int32 truncates to 0
+    float result = CalcUlduarVehicleScale(2500.0f);
+    EXPECT_FLOAT_EQ(result, 0.1f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(2500.0f), 0);
+}
+
+TEST_F(UlduarVehicleScaleTest, MinimumScalingThreshold)
+{
+    // totalILvl = 2550 -> (2550-2500)/500 = 0.1
+    // At this threshold, floor matches formula
+    float result = CalcUlduarVehicleScale(2550.0f);
+    EXPECT_FLOAT_EQ(result, 0.1f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(2550.0f), 0);
+}
+
+TEST_F(UlduarVehicleScaleTest, NaxxramasEntryGear)
+{
+    // totalILvl = 2805 (avg 187 * 15 items, typical Naxx entry)
+    // (2805 - 2500) / 500 = 0.61
+    float result = CalcUlduarVehicleScale(2805.0f);
+    EXPECT_FLOAT_EQ(result, 0.61f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(2805.0f), 0);
+}
+
+TEST_F(UlduarVehicleScaleTest, NaxxramasBiSGear)
+{
+    // totalILvl = 3000 (avg 200 * 15 items, Naxx BiS / Ulduar entry)
+    // (3000 - 2500) / 500 = 1.0
+    float result = CalcUlduarVehicleScale(3000.0f);
+    EXPECT_FLOAT_EQ(result, 1.0f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(3000.0f), 1);
+}
+
+TEST_F(UlduarVehicleScaleTest, Ulduar10Gear)
+{
+    // totalILvl = 3195 (avg 213 * 15 items, Ulduar 10)
+    // (3195 - 2500) / 500 = 1.39
+    float result = CalcUlduarVehicleScale(3195.0f);
+    EXPECT_FLOAT_EQ(result, 1.39f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(3195.0f), 1);
+}
+
+TEST_F(UlduarVehicleScaleTest, Ulduar25Gear)
+{
+    // totalILvl = 3390 (avg 226 * 15 items, Ulduar 25)
+    // (3390 - 2500) / 500 = 1.78
+    float result = CalcUlduarVehicleScale(3390.0f);
+    EXPECT_FLOAT_EQ(result, 1.78f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(3390.0f), 1);
+}
+
+TEST_F(UlduarVehicleScaleTest, UlduarBiSGear)
+{
+    // totalILvl = 3780 (avg 252 * 15 items, Ulduar BiS)
+    // (3780 - 2500) / 500 = 2.56
+    float result = CalcUlduarVehicleScale(3780.0f);
+    EXPECT_FLOAT_EQ(result, 2.56f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(3780.0f), 2);
+}
+
+TEST_F(UlduarVehicleScaleTest, ToCBiSGear)
+{
+    // totalILvl = 3884 (avg 258.9 * 15 items, ToGC BiS)
+    // (3884 - 2500) / 500 = 2.768
+    float result = CalcUlduarVehicleScale(3884.0f);
+    EXPECT_FLOAT_EQ(result, 2.768f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(3884.0f), 2);
+}
+
+TEST_F(UlduarVehicleScaleTest, ICCBiSGear)
+{
+    // totalILvl = 4162 (avg 277.5 * 15 items, ICC BiS)
+    // (4162 - 2500) / 500 = 3.324
+    float result = CalcUlduarVehicleScale(4162.0f);
+    EXPECT_FLOAT_EQ(result, 3.324f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(4162.0f), 3);
+}
+
+TEST_F(UlduarVehicleScaleTest, RSBiSGear)
+{
+    // totalILvl = 4204 (avg 280.3 * 15 items, RS BiS)
+    // (4204 - 2500) / 500 = 3.408
+    float result = CalcUlduarVehicleScale(4204.0f);
+    EXPECT_FLOAT_EQ(result, 3.408f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(4204.0f), 3);
+}
+
+// =============================================================================
+// Quality penalty tests
+// =============================================================================
+
+TEST_F(UlduarVehicleScaleTest, AllEpicNoPenalty)
+{
+    // 15 epic items at avg 200: totalAdjustedILvl = 15 * 200 = 3000
+    // (3000 - 2500) / 500 = 1.0
+    float result = CalcUlduarVehicleScale(3000.0f);
+    EXPECT_FLOAT_EQ(result, 1.0f);
+}
+
+TEST_F(UlduarVehicleScaleTest, OneRareItemPenalty)
+{
+    // 14 epic (200) + 1 rare (200 - 13 = 187): totalAdjustedILvl = 14*200 + 187 = 2987
+    // (2987 - 2500) / 500 = 487/500 = 0.974
+    float result = CalcUlduarVehicleScale(2987.0f);
+    EXPECT_FLOAT_EQ(result, 0.974f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(2987.0f), 0);
+}
+
+TEST_F(UlduarVehicleScaleTest, OneUncommonItemPenalty)
+{
+    // 14 epic (200) + 1 uncommon (200 - 26 = 174): totalAdjustedILvl = 14*200 + 174 = 2974
+    // (2974 - 2500) / 500 = 474/500 = 0.948
+    float result = CalcUlduarVehicleScale(2974.0f);
+    EXPECT_FLOAT_EQ(result, 0.948f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(2974.0f), 0);
+}
+
+TEST_F(UlduarVehicleScaleTest, MixedQualityPenalty)
+{
+    // 10 epic (200) + 3 rare (187) + 2 uncommon (174):
+    // totalAdjustedILvl = 10*200 + 3*187 + 2*174 = 2000 + 561 + 348 = 2909
+    // (2909 - 2500) / 500 = 409/500 = 0.818
+    float result = CalcUlduarVehicleScale(2909.0f);
+    EXPECT_FLOAT_EQ(result, 0.818f);
+}
+
+// =============================================================================
+// Floor behavior
+// =============================================================================
+
+TEST_F(UlduarVehicleScaleTest, FloorAtLowItemLevel)
+{
+    // totalILvl < 2500 → result would be negative, floor to 0.1
+    float result = CalcUlduarVehicleScale(2400.0f);
+    EXPECT_FLOAT_EQ(result, 0.1f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(2400.0f), 0);
+}
+
+TEST_F(UlduarVehicleScaleTest, FloorWithQualityPenalty)
+{
+    // totalAdjustedILvl = 2400 (e.g. sum of quality-adjusted iLvl below 2500)
+    // (2400 - 2500) / 500 = -0.2 → floor to 0.1
+    float result = CalcUlduarVehicleScale(2400.0f);
+    EXPECT_FLOAT_EQ(result, 0.1f);
+    EXPECT_EQ(CalcUlduarVehicleScaleAmount(2400.0f), 0);
+}
+
+// =============================================================================
+// Monotonicity: scaling must never decrease as totalILvl increases
+// =============================================================================
+
+TEST_F(UlduarVehicleScaleTest, MonotonicWithSameQuality)
+{
+    float prev = CalcUlduarVehicleScale(2500.0f);
+    for (float totalILvl = 2510.0f; totalILvl <= 4000.0f; totalILvl += 10.0f)
+    {
+        float curr = CalcUlduarVehicleScale(totalILvl);
+        EXPECT_GE(curr, prev) << "Scaling dropped at totalILvl=" << totalILvl;
+        prev = curr;
+    }
+}
+
+TEST_F(UlduarVehicleScaleTest, MonotonicAmountWithSameQuality)
+{
+    int32_t prev = CalcUlduarVehicleScaleAmount(2500.0f);
+    for (float totalILvl = 2510.0f; totalILvl <= 4000.0f; totalILvl += 10.0f)
+    {
+        int32_t curr = CalcUlduarVehicleScaleAmount(totalILvl);
+        EXPECT_GE(curr, prev) << "Amount dropped at totalILvl=" << totalILvl;
+        prev = curr;
+    }
+}