Implement Position-Based Random Magic Item Distribution

CMakeLists.txt

@@ -107,6 +107,7 @@ add_executable(alicia-server
         src/server/chat/AllChatDirector.cpp
         src/server/chat/PrivateChatDirector.cpp
         src/server/messenger/MessengerDirector.cpp
+        src/server/race/MagicSystem.cpp
         src/server/race/RaceInstance.cpp
         src/server/race/RaceNetworkHandler.cpp
         src/server/ranch/RanchDirector.cpp

include/libserver/network/command/proto/RaceMessageDefinitions.hpp

@@ -1542,7 +1542,7 @@ struct AcCmdUserRaceUpdatePos
   //! 1 = In the air
   uint16_t member5{};
   //! Race track progress
-  float member6{};
+  float progress{};
   //! Ticks since connected to race director?
   uint32_t member7{};
 

include/libserver/registry/MagicRegistry.hpp

@@ -20,6 +20,7 @@
 #ifndef MAGICREGISTRY_HPP
 #define MAGICREGISTRY_HPP
 
+#include <array>
 #include <cstdint>
 #include <filesystem>
 #include <unordered_map>
@@ -30,6 +31,8 @@ namespace server::registry
 
 struct Magic
 {
+  using SlotWeight = uint32_t;
+
   //! Per-magic-slot definition (MagicSlotInfo).
   struct SlotInfo
   {
@@ -67,6 +70,8 @@ struct Magic
 
     uint32_t affectByCriticalAura{};
     uint32_t criticalByDarkFire{};
+    //! Weights for each position on the scoreboard.
+    std::array<SlotWeight, 8> positionalWeights{};
   };
 
   //! Magic gauge (SP) regen settings for Magic mode.
@@ -122,6 +127,10 @@ class MagicRegistry
   //! Returns the stat scaling for a basicType, or nullptr if none applies.
   [[nodiscard]] const Magic::StatScaling* GetStatScaling(uint32_t basicType) const;
 
+  //! Returns the position weights for use in random magic selection.
+  [[nodiscard]] const std::vector<std::pair<Magic::SlotWeight, Magic::SlotInfo>>& GetSoloPositionWeights(uint32_t position) const;
+  [[nodiscard]] const std::vector<std::pair<Magic::SlotWeight, Magic::SlotInfo>>& GetTeamPositionWeights(uint32_t position) const;
+
 private:
   std::unordered_map<uint32_t, Magic::SlotInfo> _slotInfo{};
   std::vector<uint32_t> _soloPool{};
@@ -130,6 +139,9 @@ class MagicRegistry
   uint32_t _baseCritChanceBp{500};
   //! Keyed by basicType.
   std::unordered_map<uint32_t, Magic::StatScaling> _statScalings{};
+  //! Position weights for use in random magic selection.
+  std::array<std::vector<std::pair<Magic::SlotWeight, Magic::SlotInfo>>, 8> _soloPositionWeights;
+  std::array<std::vector<std::pair<Magic::SlotWeight, Magic::SlotInfo>>, 8> _teamPositionWeights;
 };
 
 } // namespace server::registry

include/server/race/MagicSystem.hpp

@@ -0,0 +1,54 @@
+/**
+ * Alicia Server - dedicated server software
+ * Copyright (C) 2026 Story Of Alicia
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ **/
+
+#ifndef MAGICSYSTEM_HPP
+#define MAGICSYSTEM_HPP
+
+#include "server/tracker/RaceTracker.hpp"
+
+#include <libserver/data/DataDefinitions.hpp>
+#include <libserver/registry/MagicRegistry.hpp>
+
+#include <cstdint>
+
+namespace server::race
+{
+
+class MagicSystem
+{
+public:
+  static uint32_t GetMountStatValue(
+    const tracker::RaceTracker::Racer::MountStatsSnapshot& stats,
+    registry::Magic::MountStat which);
+
+  //! Function to select a random item based on position weights
+  static const registry::Magic::SlotInfo& SelectMagicTypeByPosition(
+    const registry::MagicRegistry& magicRegistry,
+    uint32_t position,
+    bool isTeam);
+
+  static const registry::Magic::SlotInfo& RandomMagicItem(
+    const registry::MagicRegistry& magicRegistry,
+    tracker::RaceTracker& tracker,
+    data::Uid racerUid);
+};
+
+} // namespace server::race
+
+#endif // MAGICSYSTEM_HPP

include/server/tracker/RaceTracker.hpp

@@ -72,11 +72,15 @@ class RaceTracker
     Oid oid{InvalidEntityOid};
     State state{State::Disconnected};
     Team team{Team::Solo};
-    protocol::Vector3 position{};
+    //! The racer's position in the world, as a vector.
+    protocol::Vector3 worldPosition{};
     uint32_t starPointValue{};
     uint32_t jumpComboValue{};
     uint32_t courseTime{InvalidCourseTime};
     std::optional<uint32_t> magicItem{};
+    //! The racer's progress on the race track.
+    //! Normalised by the client to: 0.0f <= x <= 1.0f
+    float raceProgress{};
 
     //! A set of tracked items in racer's proximity.
     std::unordered_set<Oid> trackedDecks;

resources/config/game/magic.yaml

@@ -31,6 +31,7 @@ magic:
         affectByCriticalAura: 1
         criticalByDarkFire: 1
         attackRank: 2
+        positionalWeights: [1, 45, 45, 45, 30, 20, 3, 3]
 
       - type: 3               # FireBall (Critical)
         basicType: 2
@@ -90,6 +91,7 @@ magic:
         massEffect: 0
         affectByCriticalAura: 1
         criticalByDarkFire: 0
+        positionalWeights: [103, 10, 10, 5, 4, 3, 3, 3]
 
       - type: 5               # WaterShield (Critical)
         basicType: 4
@@ -148,6 +150,7 @@ magic:
         massEffect: 0
         affectByCriticalAura: 1
         criticalByDarkFire: 0
+        positionalWeights: [0, 10, 15, 18, 45, 55, 105, 105]
 
       - type: 7               # Booster (Critical)
         basicType: 6
@@ -206,6 +209,7 @@ magic:
         massEffect: 0
         affectByCriticalAura: 1
         criticalByDarkFire: 0
+        positionalWeights: [0, 0, 0, 0, 5, 20, 50, 50]
 
       - type: 9               # HotRodding (Critical)
         basicType: 8
@@ -265,6 +269,7 @@ magic:
         affectByCriticalAura: 1
         criticalByDarkFire: 0
         attackRank: 1
+        positionalWeights: [89, 35, 20, 20, 10, 12, 3, 3]
 
       - type: 11              # IceWall (Critical)
         basicType: 10
@@ -324,6 +329,7 @@ magic:
         massEffect: 0
         affectByCriticalAura: 1
         criticalByDarkFire: 0
+        positionalWeights: [0, 5, 20, 20, 30, 20, 3, 3]
 
       - type: 13              # JumpStun (Critical)
         basicType: 12
@@ -382,6 +388,7 @@ magic:
         massEffect: 0
         affectByCriticalAura: 1
         criticalByDarkFire: 0
+        positionalWeights: [5, 31, 20, 20, 17, 22, 8, 8]
 
       - type: 15              # DarkFire (Critical)
         basicType: 14
@@ -441,6 +448,7 @@ magic:
         affectByCriticalAura: 1
         criticalByDarkFire: 0
         attackRank: 2
+        positionalWeights: [1, 45, 45, 50, 35, 20, 3, 3]
 
       - type: 17              # Summon (Critical)
         basicType: 16
@@ -501,6 +509,7 @@ magic:
         affectByCriticalAura: 1
         criticalByDarkFire: 1
         attackRank: 3
+        positionalWeights: [0, 3, 3, 3, 4, 4, 4, 4]
 
       - type: 19              # Lightning (Critical)
         basicType: 18
@@ -560,6 +569,7 @@ magic:
         massEffect: 0
         affectByCriticalAura: 1
         criticalByDarkFire: 0
+        positionalWeights: [1, 6, 10, 7, 8, 8, 4, 4]
 
       - type: 21              # BufPower (Critical)
         basicType: 20
@@ -618,6 +628,7 @@ magic:
         massEffect: 0
         affectByCriticalAura: 0
         criticalByDarkFire: 0
+        positionalWeights: [0, 0, 0, 0, 0, 0, 0, 0]
 
       - type: 23              # BufGauge (Critical)
         basicType: 22
@@ -676,6 +687,7 @@ magic:
         massEffect: 0
         affectByCriticalAura: 1
         criticalByDarkFire: 0
+        positionalWeights: [0, 10, 12, 12, 12, 16, 14, 14]
 
       - type: 25              # BufSpeed (Critical)
         basicType: 24

src/libserver/network/Server.cpp

@@ -31,7 +31,7 @@ namespace server::network
 namespace
 {
 
-constexpr std::size_t MaxConnectionsPerAddress = 3;
+constexpr std::size_t MaxConnectionsPerAddress = 10;
 constexpr std::size_t MaxTotalConnections = 1024;
 constexpr std::size_t MaxConnectRatePerAddress = 10;
 constexpr auto RateWindow = std::chrono::seconds(30);

src/libserver/network/command/proto/RaceMessageDefinitions.cpp

@@ -1105,7 +1105,7 @@ void AcCmdUserRaceUpdatePos::Read(
 
   stream.Read(command.member4)
     .Read(command.member5)
-    .Read(command.member6)
+    .Read(command.progress)
     .Read(command.member7);
 }
 

src/libserver/registry/MagicRegistry.cpp

@@ -67,6 +67,10 @@ uint32_t ReadSlotInfo(const YAML::Node& section, Magic::SlotInfo& slot)
   slot.criticalByDarkFire = section["criticalByDarkFire"].as<uint32_t>();
   slot.attackRank = section["attackRank"].as<uint32_t>(0);
 
+  // Crit items do not need the positional weights defined, base items carry that info
+  if (slot.type == slot.basicType)
+    slot.positionalWeights = section["positionalWeights"].as<std::array<uint32_t, 8>>();
+
   return slot.type;
 }
 
@@ -98,14 +102,34 @@ void MagicRegistry::ReadConfig(const std::filesystem::path& configPath)
     }
   }
 
-  // Pre-build the pick pools so RandomMagicItem never has to filter at runtime.
+  // Pre-build the pick pools and positional weights so RandomMagicItem never has to filter at runtime.
   for (const auto& [type, slot] : _slotInfo)
   {
     if (slot.basicType != type)
       continue; // skip critical variants
     _teamPool.push_back(type);
     if (slot.teamMode == 0)
       _soloPool.push_back(type);
+
+    // Only compile weights from base type
+    if (slot.type != slot.basicType)
+      continue;
+
+    for (size_t i = 0; i < slot.positionalWeights.size(); ++i)
+    {
+      const auto& pair = std::make_pair(
+        slot.positionalWeights[i],
+        slot);
+
+      // Add to team magic item weights since team is a superset of solo
+      _teamPositionWeights[i].emplace_back(pair);
+
+      // Do not add to solo position weights if team item
+      if (slot.teamMode != 0)
+        continue;
+
+      _soloPositionWeights[i].emplace_back(pair);
+    }
   }
 
   if (const auto regenSection = magicSection["regen"])
@@ -202,4 +226,14 @@ const Magic::StatScaling* MagicRegistry::GetStatScaling(uint32_t basicType) cons
   return it == _statScalings.cend() ? nullptr : &it->second;
 }
 
+const std::vector<std::pair<Magic::SlotWeight, Magic::SlotInfo>>& MagicRegistry::GetSoloPositionWeights(uint32_t position) const
+{
+  return _soloPositionWeights.at(position);
+}
+
+const std::vector<std::pair<Magic::SlotWeight, Magic::SlotInfo>>& MagicRegistry::GetTeamPositionWeights(uint32_t position) const
+{
+  return _teamPositionWeights.at(position);
+}
+
 } // namespace server::registry