Unity 2D Game Development, Implementing Leaderboard System Build a leaderboard that saves player scores and allows competition with users around the world.

Today, we will learn how to build a leaderboard system, which is one of the essential features in Unity 2D game development. Leaderboards are important elements that record player scores and promote competition among users. In this article, we will explain the entire process and key codes required to implement a leaderboard system step by step.

What is a Leaderboard System?

A leaderboard system is an interface that stores the scores of game players on a cloud server and displays them for users to view. This system enhances the competitiveness of the game and increases players’ sense of achievement.

Purpose of Implementing a Leaderboard System

  • Allows recording and management of player scores.
  • Enables comparison of one’s score with other players worldwide.
  • Enhances players’ sense of achievement and encourages them to challenge the game again.

Contents Covered in This Article

  1. Overview of Leaderboard System Design
  2. Data Storage through Integration with Cloud Firestore
  3. Building Leaderboard UI in Unity
  4. Implementing Leaderboard Score Update and Query Functions
  5. Final Summary and Additional Considerations

1. Overview of Leaderboard System Design

To design a leaderboard system, we first need to define the data structure. Typically, a leaderboard includes player names, scores, play time, and so on. For example, we can design the data in the following format:


{
    "leaderboard": [
        {
            "playerName": "Player1",
            "score": 1000,
            "time": "2023-10-01T10:00:00Z"
        },
        {
            "playerName": "Player2",
            "score": 900,
            "time": "2023-10-01T09:30:00Z"
        }
    ]
}

2. Data Storage through Integration with Cloud Firestore

Before implementation, let’s look at how to save and manage scores using Firebase and Firestore services. Firebase helps to securely store leaderboard data and retrieve it easily. Follow the steps below to create a Firebase project and set up Firestore.

2.1 Create a Firebase Project

  1. Visit the Firebase Console and create a new project.
  2. After creating the project, enable the Firestore database.
  3. Select Cloud Firestore and proceed to create the database.

2.2 Install Firebase SDK in Unity

  1. Download the Unity SDK from the official Firebase website.
  2. Add the Firebase package to the Unity project and install the necessary modules.
  3. Ensure to check the Firestore module to use leaderboard features.

2.3 Set Firestore Data Structure

Set the database structure to be used in Firestore. Create a collection named ‘leaderboard’ and create documents to store player scores within it.

3. Building Leaderboard UI in Unity

To implement the leaderboard feature, set up the UI. You can design the user interface using Unity’s Canvas.

3.1 Add UI Components

  1. Create a Canvas. (GameObject > UI > Canvas)
  2. Add a Text UI element for the leaderboard title.
  3. Add a Scroll View to display scores in a list format.
  4. Place a Text UI element within the Scroll View to display each player’s score.

3.2 Write a Script to Display Scores


using UnityEngine;
using UnityEngine.UI;
using Firebase.Firestore;
using System.Collections.Generic;

public class LeaderboardManager : MonoBehaviour
{
    public Text leaderboardTitle;
    public Transform contentParent;
    public GameObject scoreEntryPrefab;

    private FirebaseFirestore db;

    void Start()
    {
        db = FirebaseFirestore.DefaultInstance;
        LoadLeaderboard();
    }

    void LoadLeaderboard()
    {
        db.Collection("leaderboard").OrderBy("score", descending: true).Limit(10).GetSnapshotAsync().ContinueWith(task =>
        {
            if (task.IsCompleted)
            {
                foreach (var document in task.Result.Documents)
                {
                    string playerName = document.GetValue("playerName");
                    long score = document.GetValue("score");
                    DisplayScore(playerName, score);
                }
            }
        });
    }

    void DisplayScore(string playerName, long score)
    {
        GameObject entry = Instantiate(scoreEntryPrefab, contentParent);
        entry.GetComponent().Setup(playerName, score);
    }
}

4. Implementing Score Update and Query Functions for the Leaderboard

Now, let’s implement the functionality to update and query player scores. To do this, we will write a method to record scores and call this method when a player’s score updates in the game.

4.1 Add Score Update Method


public void UpdateScore(string playerName, long score)
{
    DocumentReference docRef = db.Collection("leaderboard").Document(playerName);
    docRef.SetAsync(new { playerName = playerName, score = score }, SetOptions.MergeAll);
}

4.2 Call Score Update in the Game

In the game, call the above method to update the score when a player earns points or when the game ends.


void EndGame()
{
    UpdateScore(playerName, currentScore);
}

5. Final Summary and Additional Considerations

In conclusion, we have explained how to implement a leaderboard system in Unity 2D games. This system is a very important feature that promotes competition among players and adds excitement to the game.

Additionally, you may consider adding various filtering features (for example, weekly, monthly rankings) to the leaderboard, or implementing a reward system for players. By evolving the leaderboard system in such ways, you can significantly enhance the user experience.

I hope this article has helped with Unity game development, and if you have any questions or additional topics you’d like to see, please leave a comment!