UEproject

An Unreal Engine 5 RPG prototype written in C++. The project explores core RPG systems from scratch: NPC AI with scheduled daily routines, a waynet-based pathfinding graph, a dialog system, an inventory with weapon equipping, and a data-driven NPC pipeline powered by XML. Also includes a formal EBNF grammar sketch for a custom in-game scripting language.

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Features

Waynet & Pathfinding

NPCs navigate the world via a waynet — a graph of Waypoint actors connected by edges. The WaynetHandler implements multiple graph search algorithms for NPC pathfinding, allowing characters to route between named waypoints at runtime.

NPC Daily Routines

Each NPC has a list of DailyRoutine entries. Every entry pairs an IngameTime (hour + minute) with a DailyRoutineActivities enum value and a target waypoint name. The AI evaluates the current in-game time and dispatches the NPC to the appropriate location and activity on schedule.

XML-Driven NPC Data

NPC definitions live in Data/DATA_NPC.xml and are loaded at runtime via XMLHandler, which wraps Unreal's FXmlFile. For each NPC the file stores:

• Attributes: name, id, level, learning points, current/max HP, current/max mana
• Spawnpoint: name of the waypoint the NPC spawns at
• Daily routines: list of scheduled time/waypoint/activity entries

Dialog System

UDialog holds an identifier, a title line displayed in the UI, and a sequential list of UDialogInstruction objects. Calling start() executes all instructions in order. DialogOptionsWidget, DialogLineWidget, and SubtitleWidget handle the in-world UI presentation.

Inventory System

UInventoryComponent is an actor component attached to characters. It supports:

• Fixed-size slot grid with stackable and non-stackable item handling
• Partial stacks — new items fill existing partial stacks before creating new ones
• Overflow splitting — quantities exceeding maxStackSize are automatically split across multiple stacks
• Weapon equipping with three named attach points: Right, Left, Back
• Toggleable inventory window (InventoryWindowWidget) that switches input mode between UI and game

Quest System

QuestHandler, Quest, QuestSubpart, and QuestLogWidget are scaffolded and ready for implementation.

Custom Scripting Language (EBNF)

ebnf_updated.g4 defines a formal grammar for an in-game scripting language named RPG. It covers:

• Types: int, int64, uint, uint64, bool, char, wchar, string
• Control flow: if/else if/else, for, while, return
• Arithmetic: addition, subtraction, multiplication, division, boolean flip
• Game declarations: NPC { ... } and ITEM { ... } blocks
• Character set: full Latin alphabet including German umlauts (ä, ö, ü, ß)

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Project Structure

UEproject/
├── Data/
│   └── DATA_NPC.xml          # NPC definitions (attributes, spawnpoints, routines)
├── AICharacter.cpp/.h         # AI character base class
├── RPGAIController.cpp/.h     # AI controller
├── NPCController.cpp/.h       # NPC-specific controller logic
├── NPCDataHandler.cpp/.h      # Bridges XMLHandler data to NPC actors
├── WaynetHandler.cpp/.h       # Waynet graph + pathfinding algorithms
├── Waypoint.cpp/.h            # Waypoint actor
├── DailyRoutine.cpp/.h        # Time-based NPC schedule entry
├── IngameTime.cpp/.h          # In-game clock (hour/minute)
├── Dialog.cpp/.h              # Dialog object (id, title, instructions)
├── DialogInstruction.cpp/.h   # Executable dialog instruction
├── DialogLineWidget.cpp/.h    # UI: single dialog line
├── DialogOptionsWidget.cpp/.h # UI: dialog choice list
├── SubtitleWidget.cpp/.h      # UI: subtitle/speech display
├── FocusWidget.cpp/.h         # UI: world-space focus indicator
├── FocusWidgetComponent.cpp/.h
├── InventoryComponent.cpp/.h  # Inventory actor component
├── InventorySlotWidget.cpp/.h
├── InventoryTooltipWidget.cpp/.h
├── InventoryWindowWidget.cpp/.h
├── Item.cpp/.h                # Base item class
├── Item_Weapon.cpp/.h         # Weapon item with attach points
├── Item_Miscellaneous.cpp/.h
├── Container.cpp/.h           # World container (chest, etc.)
├── Quest.cpp/.h
├── QuestSubpart.cpp/.h
├── QuestHandler.cpp/.h
├── QuestLogWidget.cpp/.h
├── XMLHandler.cpp/.h          # XML NPC data loader
├── RPGGameInstance.cpp/.h     # Game instance (persistent state)
├── RPGPlayerController.cpp/.h
├── RPG_cppCharacter.cpp/.h    # Player character
├── RPG_cppGameMode.cpp/.h
├── UI.cpp/.h                  # Main HUD widget
├── InteractInterface.cpp/.h   # Interface for interactable actors
├── RPG_cpp.Build.cs           # Unreal build rules
└── ebnf_updated.g4            # EBNF grammar for RPG scripting language

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Requirements

• Unreal Engine 5.0
• Visual Studio 2019 or later (Windows)
• No third-party plugins required — uses only built-in UE5 modules (XmlParser, UMG, AIModule, NavigationSystem)

Building

1. Clone the repository.
2. Update the hardcoded XML path in XMLHandler.cpp to match your local project directory.
3. Right-click the .uproject file and select Generate Visual Studio project files.
4. Open the solution in Visual Studio and build.

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Notes

• The XML path in XMLHandler.cpp is currently hardcoded to C:\dev\Unreal Projects\RPG_cpp 5.0\... and must be updated before the NPC data pipeline will work.
• The quest system is scaffolded but not yet implemented.
• This is a prototype / learning project and does not represent a complete or shippable game.