1. Introduction

In this tutorial, we'll be creating a multiplayer VR game from scratch. Our focus will be to enable real-time interaction between users in a VR environment.

You will learn:
- Basic principles of VR and multiplayer game development
- How to use Unity game engine and Photon Unity Networking (PUN) for multiplayer functionality
- How to manage player interaction in a VR environment

Prerequisites:
- Basic understanding of C# and Unity
- Unity game engine installed on your computer
- A compatible VR headset (such as Oculus Rift or HTC Vive)

2. Step-by-Step Guide

2.1 Unity and PUN Setup

First, you need to create a new Unity project. Download and install the PUN 2 package from Unity's Asset Store to enable multiplayer functionality.

2.2 Creating the VR Environment

Use Unity's inbuilt tools to create your game environment. Here, you can design the game world as per your preference.

2.3 Player Setup

You need to create a player object that represents each user in the VR environment. This includes creating a VR camera rig, which will be used to track the player's movements and rotation.

2.4 Networking

Setting up the networking component involves creating a 'Photon View' for each player object. This allows the game to keep track of each player's position and actions.

2.5 Interaction

Enable interaction between the players by programming the game mechanics. This may include picking up objects, moving around, or interacting with other elements in the VR environment.

3. Code Examples

3.1 Creating the VR Camera Rig

// This script will be attached to the Player object

using UnityEngine;
using Valve.VR;

public class Player : MonoBehaviour {
  public SteamVR_Behaviour_Pose pose;
  public SteamVR_Action_Boolean moveAction;

  private float speed = 3.0f;
  private float sensitivity = 0.1f;
  private float moveValue;

  void Update() {
    moveValue = moveAction.GetAxis(pose.inputSource);

    if (moveValue > 0.2f || moveValue < -0.2f) {
      Vector3 direction = Player.instance.hmdTransform.TransformDirection(new Vector3(0, 0, moveValue));
      Player.instance.transform.position += speed * Time.deltaTime * Vector3.ProjectOnPlane(direction, Vector3.up);
    }
  }
}

This script will be attached to the Player object, and uses the SteamVR plugin to track the player's position and movements.

3.2 Photon View Setup

// This script will be attached to the Player object

using UnityEngine;
using Photon.Pun;

public class Player : MonoBehaviourPunCallbacks {
  void Start() {
    if (photonView.IsMine) {
      // The player is the local player
    } else {
      // The player is another player
    }
  }
}

The PhotonView component tracks the player's position and actions across the network.

4. Summary

In this tutorial, we covered the process of creating a multiplayer VR game. We learned how to set up Unity and PUN, create a VR environment, set up players, handle networking, and enable interaction between players.

Next, you can explore more advanced features such as voice chat, more complex game mechanics, and VR-specific interactions.

5. Practice Exercises

1. Create a multiplayer VR game where players can throw objects at each other.
2. Build a VR game where players can collaborate to solve puzzles.
3. Develop a VR game where players can explore a virtual environment together.

Remember, the key to learning is practice. So, keep creating and experimenting with different types of games and mechanics. Happy coding!