Expand to see message attributes Welcome to the Rehti MMORPG repository! This project implements a MMORPG game written in C++.

Table of contents:

Introduction
Gameplay
How to play
Installation
Development
Technical overview
- Client
- Server
- Database
- API
Project practices

Introduction

Rehti MMORPG is heavily inspired by Old School Runescape. In the core of the project is the game engine which implements all of the game's functionalities and supporting elements. On top of the engine we have built a highly customisable game (content-wise). To learn more about the game's content and elements, see the assets document.

Gameplay

In the game, the player controls their own character in a 3D game world. Players can move around the world and explore their surroundings. The game world includes characters controlled by other players as well as non-playable characters (NPCs). Players can attack other players and NPCs. When characters die, they drop their items on the ground. The player's character has skills categorized into resource gathering skills, resource processing skills, and combat skills.

Resource gathering skills include woodcutting, mining, and fishing. The commonality among these is that by developing these skills, players acquire resources. In woodcutting, players can interact with the game world's trees to obtain wood resources. In mining, players can interact with the game world's ore rocks to obtain ore resources. In fishing, players can interact with the game world's bodies of water to obtain raw fish.

Resource processing skills include smithing and cooking. In smithing, players can utilize the ore resources obtained through mining to smith various equipment that the player can wear and use in combat. With cooking, players can use the raw fish obtained through fishing to cook edible fish. These food resources allow players to recover from combat injuries.

Combat skills include accuracy, strength, and defense. The purpose of these skills is to improve the player's ability to succeed in combat against other characters. Accuracy enhances the likelihood of the character's attacks hitting (with additional considerations for equipment). Strength affects the amount of damage the player deals, and defense increases the likelihood of the player evading attacks. Players utilize combat skills by either attacking other characters or defending against attacks from other characters. Combat can be initiated by clicking on another character, causing the player's character to commence attacking the target.

The game, in its sandbox-style, allows players to set their own goals. This could involve peaceful skill development, enhancing the character's combat strength, or even collecting items, depending on the player's preferences.

How to play

You can play the game by installing the client, see here.

Login/Signup

When you start the client, you will be prompted to input your username and password in the console. If you don't have an account, you can simply input a new username and password and you will be automatically signed up. If you already have an account, you can input your username and password and you will be logged in.

Controls

All the controls happen with the mouse.

Moving You can move your character by clicking on the ground (Both left and right click work). You can interact with objects by clicking on them.

Attacking You can attack characters (Players and NPC's) by left-clicking on them.

Talking You can talk to NPC's by right-clicking on them.

Interacting with objects You can interact with objects by clicking on them (Both left and right click work).

Moving the camera You can move the camera by holding down the scroll wheel and moving the mouse. You can zoom in and out by scrolling the scroll wheel.

Managing items Items are managed from the inventory tab in the bottom right corner. A dropdown context menu opens when right-clicking on the item.

Managing equipment Equipment can be equiped from the inventory. You can unequip items by clicking on the item in the equipment tab.

Installation

Prerequisites

Make sure to fetch git submodules. This needs to be run every time new submodules are added.

git submodule update --recursive --init

Make sure you have Conan installed from, for example, here. Run the below after installation

conan profile detect --force

Make sure you have Cmake >3.27 installed

Running

The command below will build and open the client. On start client will connect to the given ip. For the official production address, ask one of the collaborators.

./scripts/run-client.sh <server-ip>

Development

Instructions to launch and run the client and server for local development:

The client
The server

Client

Prerequisites

(Optional) Add an environment variable called VK_LAYER_PATH and point it to the vulkan-validationlayers bin/json path. (Conan library directory)

Running

Start the client

./scripts/run-client.sh

Server and Database

Server runs on C++ and uses Boost.Asio for networking. Database is made with PostgreSQL. Server and database have been containerized using Docker.

Prerequisites

To run the server and database, make sure you have docker-compose and docker installed. Docker-compose installation also instructs or automagically installs Docker, depending what you choose.

Install docker-compose here.

Running

Start the server and database containers

./scripts/run-backend.sh

If the script doesn't work, you can just use docker-compose up in the root directory to start up the services.

Running with Conan

It is possible to run the server without Docker by using ./scripts/run-backend-conan.sh. NOTE: This does not start the database. Also not guaranteed to work on every platform.

Hot reload

Docker compose version 2.22 or higher needed
./scripts/run-backend.sh --watch to automatically rebuild the server every time changes occur. NOTE: Watch is an experimental docker-compose feature. In our case, this might quickly increase your docker build cache, so make sure to sometimes run docker system prune or other clean up commands.

Troubleshooting

You can debug the db contents by running psql -h 127.0.0.1 -p 6543 -U myuser -d mmorpg-database. Password is mypassword.

Technical overview

The project is divided into three main parts: the client, the server and the database. The client is responsible for rendering the game and sending user input to the server. The server is responsible for handling the game logic and sending the game state to the client. The database is responsible for storing the game state.

Technical overview

Detailed documentation of the source code can be found here.

Client

The client program is implemented in C++ and follows the object-oriented programming paradigm. Its task is to receive and parse messages coming from the server. The client program directs the graphics library based on these messages.

Graphics

The graphical backend, or graphics library, follows a class-based architecture similar to the rest of the client program, where different tasks are divided into different classes. Making the distinction between tasks is not trivial due to the complexity of the used display driver interface. The above image outlines a general architecture, the components of which will be explained in more detail in the subsections of this section. The subsections also clarify the functionality of the classes and possible actions outsourced to libraries.

Server

The server is implemented in C++. The server's main loop advances the game 32 times per second, updating each character by one iteration each time. The server continuously receives and sends messages in a separate thread.

Database

The database uses PostgreSQL version 16. The project does not demand much from the database as there are very few read and write operations. Additionally, data sizes are not expected to grow to several hundred, or even tens, of gigabytes. We could have chosen any general database technology for this reason. However, we ended up selecting PostgreSQL because we had previous experience with it, and the C++ ecosystem provided a simple interface library for the database (libpqxx).

API

Client-server communication is established over TCP, and all message bodies are in JSON format. RapidJSON library is used for message serialization and deserialization.

Message Types

Messages exchanged between the client and server are identified by a unique message type and include information about which entity sends the message (server or client). Here's a summary of the available message types:

GameStateMessage

Represents the current game state. Represents all the relevant information that client needs to be able to react and interact with the world events.

Sent by: Server

id: Identifies the message type.
entities: A collection of GameStateEntity objects representing various entities in the game world.
- id: Entity ID.
- instanceId: Instance-specific ID.
- name: Entity name.
- x: X-coordinate.
- y: Y-coordinate.
- z: Z-coordinate.
- hp: Health points.
- rotation: Rotation angle. 0-4 (North-South)
- currentAction: Current action
  - id: action id (For example, move or attack). -1 means no action
  - durationMs: duration for one action iteration
  - looping: boolean indicating if the action should loop or not
  - targetId: action target id. Interpretation depends on the action id. For example, if attack -> targetId is entityId. If move -> targetId is not defined
  - targetCoordinate: target coordinates. If action is move, can be used to determine the target coordinates. Can also be used to determine the direction of the action.
    - x: x-coordinate
    - y: y-coordinate
    - z: z-coordinate
objects: A collection of GameStateObject objects representing objects in the game world.
- id: Object ID.
- instanceId: Instance-specific ID.
- name: Object name.
- x: X-coordinate.
- y: Y-coordinate.
- z: Z-coordinate.
- rotation: Rotation angle. 0-4 (North-South).
currentPlayer: A CurrentPlayer object e.g. the player that this GameStateMessage is being sent to. Contains some info that is only exposed to the player itself.
- Inherits all the entity fields (See above)
- skills: A collection of Skill objects.
  - id: Skill ID.
  - name: Skill name.
  - xp: Experience points.
- inventory: A collection of GameItem objects.
  - id: Item ID.
  - instanceId: Instance-specific ID.
  - name: Item name.
  - stackSize: Stack size (1 for non-stackable items).

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