Golden Path Module Two

Golden Path Two continues on the work from Hello World and Golden Path One to add a few more features.

This guide covers:

• Network variables (client and server-controlled)
• Network transforms
• RPCs

note

The videos on this page were removed because they were out-of-date and caused more confusion than help. All videos in the Hello World and Golden Path series will be recreated and added back at a later time.

Prerequisites

You should have completed the Hello World project and Golden Path One before starting this tutorial.

Open your Hello World project

1. Open Unity Hub.
2. Select Hello World from the list of projects displayed.

Introducing a Server-controlled Network Variable

This section adds a Server-controlled Network Variable to the project.

1. Open the Scripts Folder.
2. Create a script called NetworkVariableTest.
3. Click the Player prefab.
4. In the Player Prefab Inspector tab, click Add Component.
5. Click Scripts, and add the NetworkVariableTest.cs script you created earlier.
6. Open the NetworkVariableTest.cs script.
7. Edit the NetworkVariableTest.cs script to match the following.

Click to show/hide the Code.

using Unity.Netcode;
using UnityEngine;

public class NetworkVariableTest : NetworkBehaviour
{
    private NetworkVariable<float> ServerUptimeNetworkVariable = new NetworkVariable<float>();
    private float last_t = 0.0f;

    public override void OnNetworkSpawn()
    {
        if (IsServer)
        {
            ServerUptimeNetworkVariable.Value = 0.0f;
            Debug.Log("Server's uptime var initialized to: " + ServerUptimeNetworkVariable.Value);
        }
    }

    void Update()
    {
        var t_now = Time.time;
        if (IsServer)
        {
            ServerUptimeNetworkVariable.Value = ServerUptimeNetworkVariable.Value + 0.1f;
            if (t_now - last_t > 0.5f)
            {
                last_t = t_now;
                Debug.Log("Server uptime var has been updated to: " + ServerUptimeNetworkVariable.Value);
            }
        }
    }
}

8. Save your scene.

Testing Server-controlled Network Variables

Now we will test the Server-controlled Network Variable works as we intended.

1. Select File > Build and Run.
2. Stop the player.
3. Launch the client and server together in a terminal as shown in Testing the command line helper.
4. After a brief delay, the client and server will spawn.
5. You should see the following in the console, showing that the server and client are sharing the variable:

Server's var initialized to: 0
Server set its var to: 0.1
Server set its var to: 3.099999
Server set its var to: 6.099997

note

Since the printing to the terminal does not happen on every tick, the numbers won't match up perfectly.

Introducing Network Transform

This section adds a Network Transform component that will move the player.

1. Click Player prefab.
2. Click Add Component in the Inspector Tab.
3. Select Netcode from the list shown.
4. Select the Network Transform component from the list shown.
5. Open the Scripts Folder.
6. Create a script called NetworkTransformTest.
7. Click the Player prefab.
8. In the Player Prefab Inspector tab, click Add Component
9. Click Scripts, and add the NetworkTransformTest.cs script you created earlier.
10. Open the NetworkTransformTest.cs script.
11. Edit the NetworkTransformTest.cs script to match the following.

Click to show/hide the Code.

using System;
using Unity.Netcode;
using UnityEngine;

public class NetworkTransformTest : NetworkBehaviour
{
    void Update()
    {
        if (IsServer)
        {
            float theta = Time.frameCount / 10.0f;
            transform.position = new Vector3((float) Math.Cos(theta), 0.0f, (float) Math.Sin(theta));
        }
    }
}

12. Save your scene.

Testing Network Transform

Now we check that the Network Transform functions correctly.

1. Select File > Build and Run.
2. Stop the player.
3. Launch the client and server together in a terminal as shown in Testing the command line helper.
4. After a brief delay, the client and server will spawn.
5. You should see the player capsule moving in a circle on both the client and the server.

Introducing RPCs

This section adds some basic RPCs to the project.

1. Open the Scripts Folder.
2. Create a script called RpcTest.
3. Click the Player prefab.
4. In the Player Prefab Inspector tab, click Add Component.
5. Click Scripts, and add the RpcTest.cs script you created earlier.
6. Open the RpcTest.cs script.
7. Edit the RpcTest.cs script to match the following.

Click to show/hide the Code.

using Unity.Netcode;
using UnityEngine;

public class RpcTest : NetworkBehaviour
{
    public override void OnNetworkSpawn()
    {
        if (!IsServer)
        {
            TestServerRpc(0);
        }
    }

    [Rpc(SendTo.ClientsAndHost)]
    void TestClientRpc(int value)
    {
        if (IsClient)
        {
            Debug.Log("Client Received the RPC #" + value);
            TestServerRpc(value + 1);
        }
    }

    [Rpc(SendTo.Server)]
    void TestServerRpc(int value)
    {
        Debug.Log("Server Received the RPC #" + value);
        TestClientRpc(value);
    }
}

9. Save your scene.

Testing RPCs

Now we will test that the client and server are both recieving the RPCs correctly.

1. Select File > Build and Run.
2. Stop the player.
3. Launch the client and server together in a terminal as shown in Testing the command line helper.
4. After a brief delay, the client and server will spawn.
5. In the console, you should expect to see the client and server sending RPC messages to each other.
6. The client kicks off the exchange in its Update call the first time with a counter value of 0.
7. It then makes an RPC call to the server with the next value. The server receives this and calls the client. In the console view, you will see:

Server Received the RPC #1
Client Received the RPC #1
Server Received the RPC #2
Client Received the RPC #2
Server Received the RPC #3
Client Received the RPC #3
...

Next Steps

See the following content to continue your journey using Netcode:

• Check out the educational samples to further explore Netcode and its abilities:
  • Boss Room
  • 2D Spaceshooter Bitesize Sample
  • Invaders Bitesize Sample
  • Client-Driven Bitesize Sample