INetworkSerializable

You can use the INetworkSerializable interface to define custom serializable types.

struct MyComplexStruct : INetworkSerializable
{
    public Vector3 Position;
    public Quaternion Rotation;

    // INetworkSerializable
    public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        serializer.SerializeValue(ref Position);
        serializer.SerializeValue(ref Rotation);
    }
    // ~INetworkSerializable
}

Types implementing INetworkSerializable are supported by NetworkSerializer, RPC s and NetworkVariable s.

[ServerRpc]
void MyServerRpc(MyComplexStruct myStruct) { /* ... */ }

void Update()
{
    if (Input.GetKeyDown(KeyCode.P))
    {
        MyServerRpc(
            new MyComplexStruct
            {
                Position = transform.position,
                Rotation = transform.rotation
            }); // Client -> Server
    }
}

Nested serial types

Nested serial types will be null unless you initialize following one of these methods:

• Manually before calling SerializeValue if serializer.IsReader (or something like that).

• Initialize in the default constructor.

This is by design. You may see the values as null until initialized. The serializer isn't deserializing them, the null value is applied before it can be serialized.

Conditional Serialization

As you have more control over serialization of a struct, you might implement conditional serialization at runtime.

The following example explores a more advanced use case.

Example: Move

public struct MyMoveStruct : INetworkSerializable
{
    public Vector3 Position;
    public Quaternion Rotation;

    public bool SyncVelocity;
    public Vector3 LinearVelocity;
    public Vector3 AngularVelocity;

    void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        // Position & Rotation
        serializer.SerializeValue(ref Position);
        serializer.SerializeValue(ref Rotation);
        
        // LinearVelocity & AngularVelocity
        serializer.SerializeValue(ref SyncVelocity);
        if (SyncVelocity)
        {
            serializer.SerializeValue(ref LinearVelocity);
            serializer.SerializeValue(ref AngularVelocity);
        }
    }
}

Reading:

• (De)serialize Position back from the stream.

• (De)serialize Rotation back from the stream.

• (De)serialize SyncVelocity back from the stream.

• Check if SyncVelocity is set to true, if so:

  • (De)serialize LinearVelocity back from the stream.

  • (De)serialize AngularVelocity back from the stream.

Writing:

• Serialize Position into the stream.

• Serialize Rotation into the stream.

• Serialize SyncVelocity into the stream.

• Check if SyncVelocity is set to true, if so:

  • Serialize LinearVelocity into the stream.

  • Serialize AngularVelocity into the stream.

• If the SyncVelocity flag is set to true, serialize both the LinearVelocity and AngularVelocity into the stream.

• When the SyncVelocity flag is set to false, leave LinearVelocity and AngularVelocity with default values.

Recursive Nested Serialization

It's possible to recursively serialize nested members with INetworkSerializable interface down in the hierarchy tree.

Review the following example:

public struct MyStructA : INetworkSerializable
{
    public Vector3 Position;
    public Quaternion Rotation;

    void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        serializer.SerializeValue(ref Position);
        serializer.SerializeValue(ref Rotation);
    }
}

public struct MyStructB : INetworkSerializable
{
    public int SomeNumber;
    public string SomeText;
    public MyStructA StructA;
    
    void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        serializer.SerializeValue(ref SomeNumber);
        serializer.SerializeValue(ref SomeText);
        StructA.NetworkSerialize(serializer);
    }
}

If you were to serialize MyStructA alone, it would serialize Position and Rotation into the stream using NetworkSerializer.

However, if you were to serialize MyStructB, it would serialize SomeNumber and SomeText into the stream, then serialize StructA by calling MyStructA 's void NetworkSerialize(NetworkSerializer) method, which serializes Position and Rotation into the same stream.

note

Technically, there is no hard-limit on the number of INetworkSerializable fields you can serialize down the tree hierarchy. In practice, consider memory and bandwidth boundaries for best performance.

tip

You can conditionally serialize in recursive nested serialization scenario and make use of both features.

caution

While you can have nested INetworkSerializable implementations (an INetworkSerializable implementation with INetworkSerializable implementations as properties) like demonstrated in the example above, you can't have derived children of an INetworkSerializable implementation.
Unsupported Example

/// This isn't supported.
public struct MyStructB : MyStructA
{
    public int SomeNumber;
    public string SomeText;
    
    void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
    {
        serializer.SerializeValue(ref SomeNumber);
        serializer.SerializeValue(ref SomeText);
        serializer.SerializeValue(ref Position);
        serializer.SerializeValue(ref Rotation);
    }
}