megakoop/Game/Scripts/Networking/SteamNetworkTransform.cs

using Steamworks;
using UnityEngine;

namespace MegaKoop.Game.Networking
{
    /// <summary>
    /// Host-authoritative transform replication that mirrors state to all peers via Steam P2P messages.
    /// </summary>
    [DisallowMultipleComponent]
    public class SteamNetworkTransform : MonoBehaviour
    {
        [Header("References")]
        [SerializeField] private Transform targetTransform;
        [SerializeField] private NetworkIdentity identity;
        [SerializeField] private Rigidbody trackedRigidbody;
        [SerializeField] private UnityEngine.AI.NavMeshAgent trackedNavMeshAgent;

        [Header("Authority")]
        [SerializeField] private bool authorityIsHost = true;
        [SerializeField] private bool simulateWhenDisconnected = true;

        [Header("Synchronization")]
        [SerializeField] private float broadcastInterval = 0.05f;
        [SerializeField] private float remoteLerpSpeed = 12f;
        [SerializeField] private float teleportThreshold = 4f;

        private SteamCoopNetworkManager networkManager;
        private float broadcastTimer;
        private bool isRegistered;
        private Vector3 remoteTargetPosition;
        private Quaternion remoteTargetRotation;
        private Vector3 remoteTargetVelocity;
        private bool haveRemoteState;

        private void Awake()
        {
            if (targetTransform == null)
            {
                targetTransform = transform;
            }

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

            if (trackedRigidbody == null)
            {
                trackedRigidbody = GetComponent<Rigidbody>();
            }

            if (trackedNavMeshAgent == null)
            {
                trackedNavMeshAgent = GetComponent<UnityEngine.AI.NavMeshAgent>();
            }

            remoteTargetPosition = targetTransform.position;
            remoteTargetRotation = targetTransform.rotation;
            remoteTargetVelocity = Vector3.zero;
            broadcastTimer = Random.Range(0f, Mathf.Max(0.01f, broadcastInterval));
        }

        private void OnEnable()
        {
            EnsureNetworkManager();
            RegisterHandlers();
        }

        private void OnDisable()
        {
            UnregisterHandlers();
        }

        private void Update()
        {
            RefreshNetworkManager();

            if (HasAuthority())
            {
                broadcastTimer -= Time.deltaTime;
                if (broadcastTimer <= 0f)
                {
                    BroadcastState();
                    broadcastTimer = Mathf.Max(0.01f, broadcastInterval);
                }
            }
            else if (haveRemoteState)
            {
                float lerpFactor = Mathf.Clamp01(remoteLerpSpeed * Time.deltaTime);
                Vector3 currentPosition = targetTransform.position;
                float sqrDistance = (remoteTargetPosition - currentPosition).sqrMagnitude;
                if (sqrDistance >= teleportThreshold * teleportThreshold)
                {
                    targetTransform.SetPositionAndRotation(remoteTargetPosition, remoteTargetRotation);
                }
                else
                {
                    targetTransform.position = Vector3.Lerp(currentPosition, remoteTargetPosition, lerpFactor);
                    targetTransform.rotation = Quaternion.Slerp(targetTransform.rotation, remoteTargetRotation, lerpFactor);
                }
            }
        }

        private void RefreshNetworkManager()
        {
            if (networkManager == null)
            {
                networkManager = SteamCoopNetworkManager.Instance;
                if (networkManager != null && isActiveAndEnabled)
                {
                    RegisterHandlers();
                }
            }
        }

        private void EnsureNetworkManager()
        {
            RefreshNetworkManager();
        }

        private bool HasAuthority()
        {
            if (!authorityIsHost)
            {
                return true;
            }

            if (networkManager == null)
            {
                return simulateWhenDisconnected;
            }

            if (!networkManager.IsConnected)
            {
                return simulateWhenDisconnected;
            }

            return networkManager.IsHost;
        }

        private void BroadcastState()
        {
            if (identity == null || targetTransform == null || networkManager == null)
            {
                return;
            }

            Vector3 velocity = Vector3.zero;
            if (trackedNavMeshAgent != null && trackedNavMeshAgent.enabled)
            {
                velocity = trackedNavMeshAgent.velocity;
            }
            else if (trackedRigidbody != null)
            {
                velocity = trackedRigidbody.velocity;
            }

            SteamCharacterStateCache.ReportLocalState(identity.NetworkId, targetTransform.position, targetTransform.rotation, velocity);
            var message = new CharacterTransformMessage(identity.NetworkId, targetTransform.position, targetTransform.rotation, velocity);
            byte[] payload = CharacterTransformMessage.Serialize(message);
            networkManager.SendToAll(NetworkMessageType.CharacterTransform, payload, EP2PSend.k_EP2PSendUnreliableNoDelay);
        }

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

            networkManager.RegisterHandler(NetworkMessageType.CharacterTransform, HandleTransformMessage);
            isRegistered = true;
        }

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

            networkManager.UnregisterHandler(NetworkMessageType.CharacterTransform, HandleTransformMessage);
            isRegistered = false;
        }

        private void HandleTransformMessage(NetworkMessage message)
        {
            if (identity == null || targetTransform == null)
            {
                return;
            }

            if (HasAuthority())
            {
                return;
            }

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

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

        private void OnValidate()
        {
            broadcastInterval = Mathf.Max(0.01f, broadcastInterval);
            remoteLerpSpeed = Mathf.Max(0f, remoteLerpSpeed);
            teleportThreshold = Mathf.Max(0.01f, teleportThreshold);
        }
    }
}