Unity Basics Course: Player Synchronization and Character Attacks

As the importance of multiplayer games in modern game development increases, synchronization between players and an attack system are essential. This tutorial will provide a detailed explanation of how to implement synchronization and attacks between player characters in a multiplayer game using Unity.

1. Overview of Unity and Multiplayer Game Development

Unity is a powerful game engine that supports cross-platform development, allowing you to create both 2D and 3D games. Unity’s multiplayer capabilities offer various options such as Photon and Unity Multiplayer. In this tutorial, we will use Photon Unity Networking (PUN) to implement the synchronization and attack systems.

2. Setting up Photon Unity Networking (PUN)

To use PUN, you first need to download and install the Photon PUN 2 package from the Unity Asset Store. Alternatively, you can download the PUN SDK from the official Photon website.

2.1 Installing PUN

  1. Open the Unity editor and create a new project.
  2. Access the Asset Store, search for ‘Photon PUN 2’, and download it.
  3. Import the PUN package into your project.
  4. Run the Photon setup wizard to enter your app ID and complete the setup.

2.2 Setting up the Basic Scene

After installing Photon, set up the basic scene. You can manage the synchronization of each player by creating instances and adding the PhotonView component.

3. Setting up Player Characters and Animations

To set up the player character, import a model and add animations. We will use Rigidbody and Capsule Collider.

3.1 Importing Character Model

First, import your character model into the Unity project. After importing, it needs to be converted into a prefab.

3.2 Creating Player Prefab

  1. Place the character model in the scene.
  2. Add Rigidbody and Capsule Collider.
  3. Add PhotonView and set the Observable properties.
  4. If necessary, set up an animation controller to manage the character animations.

4. Implementing Player Movement and Synchronization

Write a script to control player movement, synchronizing each player’s position and orientation. Below is an example of the PlayerController script.


using UnityEngine;
using Photon.Pun;

public class PlayerController : MonoBehaviourPunCallbacks
{
    float speed = 5.0f;
    void Update()
    {
        if (!photonView.IsMine) return;

        float moveHorizontal = Input.GetAxis("Horizontal");
        float moveVertical = Input.GetAxis("Vertical");

        Vector3 movement = new Vector3(moveHorizontal, 0.0f, moveVertical);
        transform.position += movement * speed * Time.deltaTime;
        
        // Rotate character based on movement direction
        if (movement != Vector3.zero)
        {
            transform.rotation = Quaternion.LookRotation(movement);
        }
    }
}

4.1 Synchronization and Interpolation Handling

To add synchronization between player characters to the above code, you can add PhotonTransformView to automatically synchronize each player’s position and rotation data.

5. Implementing the Attack System

To handle attacks between players, we will use raycasting to determine hit and create mechanisms for attack handling.

5.1 Setting up Attack Animation

Set the character’s attack animation using the Unity animation system. The animation should play when attacking and detect collisions with enemies.

5.2 Implementing Attack Logic


using UnityEngine;
using Photon.Pun;

public class Attack : MonoBehaviourPunCallbacks
{
    public float attackRange = 1.0f;
    public LayerMask enemyLayer;

    void Update()
    {
        if (!photonView.IsMine) return;
        
        if (Input.GetKeyDown(KeyCode.Space))
        {
            AttackEnemy();
        }
    }

    void AttackEnemy()
    {
        RaycastHit hit;
        if (Physics.Raycast(transform.position, transform.forward, out hit, attackRange, enemyLayer))
        {
            // Handle hit
            Debug.Log("Enemy hit: " + hit.collider.name);
        }
    }
}

6. Handling Multiplayer and Synchronization

When each player performs an attack, the results need to be synchronized over the network. We will use RPC (Remote Procedure Call) to invoke specific methods for all players.

6.1 Synchronizing Attacks through RPC


[PunRPC]
public void PerformAttack()
{
    // Play attack animation
    // Handle hit
}

6.2 Calling RPC


void AttackEnemy()
{
    // Hit logic
    photonView.RPC("PerformAttack", RpcTarget.All);
}

7. Handling Game Over and Results

To automatically synchronize all players’ lives and game over status, you need to write a script to manage each player’s state. In this step, we will set victory or defeat conditions and transmit the results over the network.

7.1 Managing Lives and Game Over Handling


public class GameManager : MonoBehaviourPunCallbacks
{
    public int playerLives = 3;

    public void PlayerDied()
    {
        playerLives--;
        if (playerLives <= 0)
        {
            photonView.RPC("GameOver", RpcTarget.All);
        }
    }

    [PunRPC]
    public void GameOver()
    {
        Debug.Log("Game Over");
        // Game result handling code
    }
}

8. Conclusion

Through this tutorial, you have learned how to implement player synchronization and attack systems in a multiplayer game using Unity. Each step helps to enhance your understanding of network programming and game logic processing. By leveraging Unity's features, you can develop more sophisticated games. Now you can further advance your multiplayer project with custom characters and attack mechanisms.

I hope this tutorial will be helpful for your multiplayer game development in Unity. If you have additional questions or want more in-depth content, please leave a comment. Wishing you much success in your game development journey!