megakoop/Game/Scripts/Networking/SteamCharacterNetworkBridge.cs

using Steamworks;
using UnityEngine;

namespace MegaKoop.Game.Networking
{
    [DisallowMultipleComponent]
    public class SteamCharacterNetworkBridge : MonoBehaviour
    {
        [Header("References")]
        [SerializeField] private ThirdPersonCharacterController characterController;
        [SerializeField] private NetworkIdentity identity;
        [SerializeField] private Transform rootTransform;
        [SerializeField] private NetworkCharacterInputProxy networkInputProxy;

        [Header("Settings")]
        [SerializeField] private float transformBroadcastInterval = 0.05f;
        [SerializeField] private float remoteLerpSpeed = 12f;
        [SerializeField] private ulong ownerSteamId;
        [SerializeField] private bool autoAssignOwnerToLocalPlayer = true;

        private SteamCoopNetworkManager networkManager;
        private float broadcastTimer;
        private bool isRegistered;
        private bool isLocalPlayer;
        private bool isAuthority;

        private Vector3 remoteTargetPosition;
        private Quaternion remoteTargetRotation;
        private Vector3 remoteTargetVelocity;
        private bool haveRemoteState;
        private bool localOverrideSet;

        public void AssignOwner(ulong steamId, bool localPlayer)
        {
            ownerSteamId = steamId;
            isLocalPlayer = localPlayer;
            localOverrideSet = true;
            UpdateAuthority();
            ConfigureController();
        }

        public bool IsLocalPlayer => isLocalPlayer;
        public bool IsAuthority => isAuthority;

        private void Awake()
        {
            if (characterController == null)
            {
                characterController = GetComponent<ThirdPersonCharacterController>();
            }

            if (identity == null)
            {
                identity = GetComponent<NetworkIdentity>();
            }

            if (rootTransform == null)
            {
                rootTransform = transform;
            }

            if (networkInputProxy == null)
            {
                networkInputProxy = GetComponent<NetworkCharacterInputProxy>();
                if (networkInputProxy == null)
                {
                    networkInputProxy = gameObject.AddComponent<NetworkCharacterInputProxy>();
                    networkInputProxy.hideFlags = HideFlags.HideInInspector;
                }
            }

            remoteTargetPosition = rootTransform.position;
            remoteTargetRotation = rootTransform.rotation;
        }

        private void Start()
        {
            networkManager = SteamCoopNetworkManager.Instance;
            UpdateAuthority();
            ConfigureController();
        }

        private void OnEnable()
        {
            networkManager = SteamCoopNetworkManager.Instance;
            RegisterHandlers();
        }

        private void OnDisable()
        {
            UnregisterHandlers();
        }

        private void Update()
        {
            if (networkManager == null)
            {
                return;
            }

            if (isAuthority)
            {
                broadcastTimer -= Time.deltaTime;
                if (broadcastTimer <= 0f)
                {
                    BroadcastTransform();
                    broadcastTimer = transformBroadcastInterval;
                }
            }
            else
            {
                if (haveRemoteState)
                {
                    rootTransform.position = Vector3.Lerp(rootTransform.position, remoteTargetPosition, remoteLerpSpeed * Time.deltaTime);
                    rootTransform.rotation = Quaternion.Slerp(rootTransform.rotation, remoteTargetRotation, remoteLerpSpeed * Time.deltaTime);
                }
            }
        }

        private void RegisterHandlers()
        {
            if (networkManager == null || isRegistered)
            {
                return;
            }

            networkManager.RegisterHandler(NetworkMessageType.PlayerInput, HandlePlayerInputMessage);
            networkManager.RegisterHandler(NetworkMessageType.CharacterTransform, HandleCharacterTransformMessage);
            isRegistered = true;
        }

        private void UnregisterHandlers()
        {
            if (networkManager == null || !isRegistered)
            {
                return;
            }

            networkManager.UnregisterHandler(NetworkMessageType.PlayerInput, HandlePlayerInputMessage);
            networkManager.UnregisterHandler(NetworkMessageType.CharacterTransform, HandleCharacterTransformMessage);
            isRegistered = false;
        }

        private void UpdateAuthority()
        {
            if (networkManager == null)
            {
                networkManager = SteamCoopNetworkManager.Instance;
            }

            bool isHost = networkManager != null && networkManager.IsHost;
            ulong localSteamId = SteamBootstrap.IsInitialized ? SteamUser.GetSteamID().m_SteamID : 0UL;

            if (!localOverrideSet && autoAssignOwnerToLocalPlayer && ownerSteamId == 0 && localSteamId != 0)
            {
                ownerSteamId = localSteamId;
            }

            if (!localOverrideSet)
            {
                isLocalPlayer = ownerSteamId != 0 && ownerSteamId == localSteamId;
            }

            isAuthority = isHost; // Host drives authoritative simulation.
        }

        private void ConfigureController()
        {
            if (characterController == null)
            {
                return;
            }

            if (isAuthority)
            {
                characterController.enabled = true;
                characterController.SetInputSource(isLocalPlayer ? null : networkInputProxy);
            }
            else
            {
                characterController.enabled = false;
            }
        }

        private void BroadcastTransform()
        {
            if (identity == null)
            {
                return;
            }

            var unityController = GetComponent<CharacterController>();
            Vector3 velocity = unityController != null ? unityController.velocity : Vector3.zero;
            var message = new CharacterTransformMessage(identity.NetworkId, rootTransform.position, rootTransform.rotation, velocity);
            byte[] payload = CharacterTransformMessage.Serialize(message);
            networkManager.SendToAll(NetworkMessageType.CharacterTransform, payload, EP2PSend.k_EP2PSendUnreliableNoDelay);
        }

        private void HandlePlayerInputMessage(NetworkMessage message)
        {
            if (!isAuthority)
            {
                return;
            }

            PlayerInputMessage inputMessage = PlayerInputMessage.Deserialize(message.Payload);
            if (inputMessage.NetworkId != identity.NetworkId)
            {
                return;
            }

            networkInputProxy.SetInput(inputMessage.MoveInput, inputMessage.JumpPressed);
        }

        private void HandleCharacterTransformMessage(NetworkMessage message)
        {
            if (isAuthority)
            {
                return;
            }

            CharacterTransformMessage transformMessage = CharacterTransformMessage.Deserialize(message.Payload);
            if (transformMessage.NetworkId != identity.NetworkId)
            {
                return;
            }

            remoteTargetPosition = transformMessage.Position;
            remoteTargetRotation = transformMessage.Rotation;
            remoteTargetVelocity = transformMessage.Velocity;
            haveRemoteState = true;
        }

        public void SendLocalInput(Vector2 moveInput, bool jump)
        {
            if (networkManager == null || identity == null)
            {
                return;
            }

            var message = new PlayerInputMessage(identity.NetworkId, moveInput, jump, Vector2.zero);
            byte[] payload = PlayerInputMessage.Serialize(message);
            if (!networkManager.IsConnected || networkManager.IsHost)
            {
                // If we are host, feed directly.
                HandlePlayerInputMessage(new NetworkMessage(NetworkMessageType.PlayerInput, payload, SteamUser.GetSteamID().m_SteamID));
            }
            else
            {
                CSteamID lobby = networkManager.ActiveLobby;
                CSteamID lobbyOwner = lobby != CSteamID.Nil ? SteamMatchmaking.GetLobbyOwner(lobby) : CSteamID.Nil;
                if (lobbyOwner == CSteamID.Nil)
                {
                    lobbyOwner = SteamUser.GetSteamID();
                }

                networkManager.SendToPlayer(lobbyOwner, NetworkMessageType.PlayerInput, payload, EP2PSend.k_EP2PSendUnreliableNoDelay);
            }
        }
    }
}