Added lag compensation

Author: TwoTenPvP

MLAPI/Data/NetworkingConfiguration.cs

@@ -23,6 +23,7 @@ public class NetworkingConfiguration
         public bool ConnectionApproval = false;
         public Action<byte[], int, Action<int, bool>> ConnectionApprovalCallback = null;
         public byte[] ConnectionData = new byte[0];
+        public float SecondsHistory = 5;
         public bool HandleObjectSpawning = true;
         //TODO
         public bool CompressMessages = false;

MLAPI/Data/TrackedPointData.cs

@@ -0,0 +1,10 @@
+using UnityEngine;
+
+namespace MLAPI.Data
+{
+    internal struct TrackedPointData
+    {
+        internal Vector3 position;
+        internal Quaternion rotation;
+    }
+}

MLAPI/MonoBehaviours/Core/LagCompensationManager.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine.Networking;
+
+namespace MLAPI.MonoBehaviours.Core
+{
+    public static class LagCompensationManager
+    {
+        public static List<TrackedObject> SimulationObjects = new List<TrackedObject>();
+
+        public static void Simulate(float secondsAgo, Action action)
+        {
+            for (int i = 0; i < SimulationObjects.Count; i++)
+            {
+                SimulationObjects[i].ReverseTransform(secondsAgo);
+            }
+
+            action.Invoke();
+
+            for (int i = 0; i < SimulationObjects.Count; i++)
+            {
+                SimulationObjects[i].ResetStateTransform();
+            }
+        }
+
+        private static byte error = 0;
+        public static void Simulate(int clientId, Action action)
+        {
+            float milisecondsDelay = NetworkTransport.GetCurrentRTT(NetworkingManager.singleton.hostId, clientId, out error) / 2f;
+            Simulate(milisecondsDelay * 1000f, action);
+        }
+
+        internal static void AddFrames()
+        {
+            for (int i = 0; i < SimulationObjects.Count; i++)
+            {
+                SimulationObjects[i].AddFrame();
+            }
+        }
+    }
+}

MLAPI/MonoBehaviours/Core/NetworkingManager.cs

@@ -1,4 +1,5 @@
-using MLAPI.NetworkingManagerComponents;
+using MLAPI.MonoBehaviours.Core;
+using MLAPI.NetworkingManagerComponents;
 using System;
 using System.Collections;
 using System.Collections.Generic;
@@ -255,7 +256,7 @@ private void Shutdown()
         }
 
         //Receive stuff
-        int hostId;
+        internal int hostId;
         int clientId;
         int channelId;
         int receivedSize;
@@ -328,6 +329,7 @@ private void Update()
                     (messagesProcessed < NetworkConfig.MaxMessagesPerFrame || NetworkConfig.MaxMessagesPerFrame < 0));
 
             }
+            LagCompensationManager.AddFrames();
         }
 
         private IEnumerator ApprovalTimeout(int clientId)

MLAPI/MonoBehaviours/Core/TrackedObject.cs

@@ -0,0 +1,80 @@
+using MLAPI.Data;
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace MLAPI.MonoBehaviours.Core
+{
+    //Based on: https://twotenpvp.github.io/lag-compensation-in-unity.html
+    //Modified to be used with latency rather than fixed frames and subframes. Thus it will be less accrurate but more modular.
+    public class TrackedObject : MonoBehaviour
+    {
+        internal Dictionary<float, TrackedPointData> FrameData = new Dictionary<float, TrackedPointData>();
+        internal List<float> Framekeys = new List<float>() { 0 };
+        private Vector3 savedPosition;
+        private Quaternion savedRotation;
+
+        internal void ReverseTransform(float secondsAgo)
+        {
+            savedPosition = transform.position;
+            savedRotation = transform.rotation;
+            float currentTime = Time.time;
+            float targetTime = Time.time - secondsAgo;
+            float previousTime = 0;
+            float nextTime = 0;
+            for (int i = 1; i < Framekeys.Count - 1; i++)
+            {
+                if(Framekeys[i - 1] > targetTime && Framekeys[i] <= targetTime)
+                {
+                    previousTime = Framekeys[i];
+                    nextTime = Framekeys[i + 1];
+                    break;
+                }
+            }
+
+            float timeBetweenFrames = nextTime - previousTime;
+            float timeAwayFromPrevious = currentTime - previousTime;
+            float lerpProgress = timeAwayFromPrevious / timeBetweenFrames;
+            transform.position = Vector3.Lerp(FrameData[previousTime].position, FrameData[nextTime].position, lerpProgress);
+            transform.rotation = Quaternion.Slerp(FrameData[previousTime].rotation, FrameData[nextTime].rotation, lerpProgress);
+        }
+
+        internal void ResetStateTransform()
+        {
+            transform.position = savedPosition;
+            transform.rotation = savedRotation;
+        }
+
+        void Start()
+        {
+            LagCompensationManager.SimulationObjects.Add(this);
+        }
+
+        void OnDestroy()
+        {
+            LagCompensationManager.SimulationObjects.Remove(this);
+        }
+
+        internal void AddFrame()
+        {
+            float currentTime = Time.time;
+            for (int i = 0; i < Framekeys.Count; i++)
+            {
+                if (currentTime - Framekeys[i] <= NetworkingManager.singleton.NetworkConfig.SecondsHistory)
+                {
+                    for (int j = 0; j < i; j++)
+                    {
+                        FrameData.Remove(Framekeys[0]);
+                        //This is not good for performance. Other datatypes should be concidered.
+                        Framekeys.RemoveAt(0);
+                    }
+                }
+            }
+            FrameData.Add(Time.time, new TrackedPointData()
+            {
+                position = transform.position,
+                rotation = transform.rotation
+            });
+            Framekeys.Add(Time.frameCount);
+        }
+    }
+}