quantum-space-buddies/Mirror/Runtime/Transport/LatencySimulation.cs
2021-12-27 22:31:23 -08:00

281 lines
11 KiB
C#

// wraps around a transport and adds latency/loss/scramble simulation.
//
// reliable: latency
// unreliable: latency, loss, scramble (unreliable isn't ordered so we scramble)
using System;
using System.Collections.Generic;
using UnityEngine;
namespace Mirror
{
struct QueuedMessage
{
public int connectionId;
public byte[] bytes;
public float time;
}
[HelpURL("https://mirror-networking.gitbook.io/docs/transports/latency-simulaton-transport")]
[DisallowMultipleComponent]
public class LatencySimulation : Transport
{
public Transport wrap;
[Header("Common")]
[Tooltip("Spike latency via perlin(Time * speedMultiplier) * spikeMultiplier")]
[Range(0, 1)] public float latencySpikeMultiplier;
[Tooltip("Spike latency via perlin(Time * speedMultiplier) * spikeMultiplier")]
public float latencySpikeSpeedMultiplier = 1;
[Header("Reliable Messages")]
[Tooltip("Reliable latency in seconds")]
public float reliableLatency;
// note: packet loss over reliable manifests itself in latency.
// don't need (and can't add) a loss option here.
// note: reliable is ordered by definition. no need to scramble.
[Header("Unreliable Messages")]
[Tooltip("Packet loss in %")]
[Range(0, 1)] public float unreliableLoss;
[Tooltip("Unreliable latency in seconds")]
public float unreliableLatency;
[Tooltip("Scramble % of unreliable messages, just like over the real network. Mirror unreliable is unordered.")]
[Range(0, 1)] public float unreliableScramble;
// message queues
// list so we can insert randomly (scramble)
List<QueuedMessage> reliableClientToServer = new List<QueuedMessage>();
List<QueuedMessage> reliableServerToClient = new List<QueuedMessage>();
List<QueuedMessage> unreliableClientToServer = new List<QueuedMessage>();
List<QueuedMessage> unreliableServerToClient = new List<QueuedMessage>();
// random
// UnityEngine.Random.value is [0, 1] with both upper and lower bounds inclusive
// but we need the upper bound to be exclusive, so using System.Random instead.
// => NextDouble() is NEVER < 0 so loss=0 never drops!
// => NextDouble() is ALWAYS < 1 so loss=1 always drops!
System.Random random = new System.Random();
public void Awake()
{
if (wrap == null)
throw new Exception("PressureDrop requires an underlying transport to wrap around.");
}
// forward enable/disable to the wrapped transport
void OnEnable() { wrap.enabled = true; }
void OnDisable() { wrap.enabled = false; }
// noise function can be replaced if needed
protected virtual float Noise(float time) => Mathf.PerlinNoise(time, time);
// helper function to simulate latency
float SimulateLatency(int channeldId)
{
// spike over perlin noise.
// no spikes isn't realistic.
// sin is too predictable / no realistic.
// perlin is still deterministic and random enough.
float spike = Noise(Time.time * latencySpikeSpeedMultiplier) * latencySpikeMultiplier;
// base latency
switch (channeldId)
{
case Channels.Reliable:
return reliableLatency + spike;
case Channels.Unreliable:
return unreliableLatency + spike;
default:
return 0;
}
}
// helper function to simulate a send with latency/loss/scramble
void SimulateSend(int connectionId, ArraySegment<byte> segment, int channelId, float latency, List<QueuedMessage> reliableQueue, List<QueuedMessage> unreliableQueue)
{
// segment is only valid after returning. copy it.
// (allocates for now. it's only for testing anyway.)
byte[] bytes = new byte[segment.Count];
Buffer.BlockCopy(segment.Array, segment.Offset, bytes, 0, segment.Count);
// enqueue message. send after latency interval.
QueuedMessage message = new QueuedMessage
{
connectionId = connectionId,
bytes = bytes,
time = Time.time + latency
};
switch (channelId)
{
case Channels.Reliable:
// simulate latency
reliableQueue.Add(message);
break;
case Channels.Unreliable:
// simulate packet loss
bool drop = random.NextDouble() < unreliableLoss;
if (!drop)
{
// simulate scramble (Random.Next is < max, so +1)
bool scramble = random.NextDouble() < unreliableScramble;
int last = unreliableQueue.Count;
int index = scramble ? random.Next(0, last + 1) : last;
// simulate latency
unreliableQueue.Insert(index, message);
}
break;
default:
Debug.LogError($"{nameof(LatencySimulation)} unexpected channelId: {channelId}");
break;
}
}
public override bool Available() => wrap.Available();
public override void ClientConnect(string address)
{
wrap.OnClientConnected = OnClientConnected;
wrap.OnClientDataReceived = OnClientDataReceived;
wrap.OnClientError = OnClientError;
wrap.OnClientDisconnected = OnClientDisconnected;
wrap.ClientConnect(address);
}
public override void ClientConnect(Uri uri)
{
wrap.OnClientConnected = OnClientConnected;
wrap.OnClientDataReceived = OnClientDataReceived;
wrap.OnClientError = OnClientError;
wrap.OnClientDisconnected = OnClientDisconnected;
wrap.ClientConnect(uri);
}
public override bool ClientConnected() => wrap.ClientConnected();
public override void ClientDisconnect()
{
wrap.ClientDisconnect();
reliableClientToServer.Clear();
unreliableClientToServer.Clear();
}
public override void ClientSend(ArraySegment<byte> segment, int channelId)
{
float latency = SimulateLatency(channelId);
SimulateSend(0, segment, channelId, latency, reliableClientToServer, unreliableClientToServer);
}
public override Uri ServerUri() => wrap.ServerUri();
public override bool ServerActive() => wrap.ServerActive();
public override string ServerGetClientAddress(int connectionId) => wrap.ServerGetClientAddress(connectionId);
public override void ServerDisconnect(int connectionId) => wrap.ServerDisconnect(connectionId);
public override void ServerSend(int connectionId, ArraySegment<byte> segment, int channelId)
{
float latency = SimulateLatency(channelId);
SimulateSend(connectionId, segment, channelId, latency, reliableServerToClient, unreliableServerToClient);
}
public override void ServerStart()
{
wrap.OnServerConnected = OnServerConnected;
wrap.OnServerDataReceived = OnServerDataReceived;
wrap.OnServerError = OnServerError;
wrap.OnServerDisconnected = OnServerDisconnected;
wrap.ServerStart();
}
public override void ServerStop()
{
wrap.ServerStop();
reliableServerToClient.Clear();
unreliableServerToClient.Clear();
}
public override void ClientEarlyUpdate() => wrap.ClientEarlyUpdate();
public override void ServerEarlyUpdate() => wrap.ServerEarlyUpdate();
public override void ClientLateUpdate()
{
// flush reliable messages after latency
while (reliableClientToServer.Count > 0)
{
// check the first message time
QueuedMessage message = reliableClientToServer[0];
if (message.time <= Time.time)
{
// send and eat
wrap.ClientSend(new ArraySegment<byte>(message.bytes), Channels.Reliable);
reliableClientToServer.RemoveAt(0);
}
// not enough time elapsed yet
break;
}
// flush unreliable messages after latency
while (unreliableClientToServer.Count > 0)
{
// check the first message time
QueuedMessage message = unreliableClientToServer[0];
if (message.time <= Time.time)
{
// send and eat
wrap.ClientSend(new ArraySegment<byte>(message.bytes), Channels.Unreliable);
unreliableClientToServer.RemoveAt(0);
}
// not enough time elapsed yet
break;
}
// update wrapped transport too
wrap.ClientLateUpdate();
}
public override void ServerLateUpdate()
{
// flush reliable messages after latency
while (reliableServerToClient.Count > 0)
{
// check the first message time
QueuedMessage message = reliableServerToClient[0];
if (message.time <= Time.time)
{
// send and eat
wrap.ServerSend(message.connectionId, new ArraySegment<byte>(message.bytes), Channels.Reliable);
reliableServerToClient.RemoveAt(0);
}
// not enough time elapsed yet
break;
}
// flush unreliable messages after latency
while (unreliableServerToClient.Count > 0)
{
// check the first message time
QueuedMessage message = unreliableServerToClient[0];
if (message.time <= Time.time)
{
// send and eat
wrap.ServerSend(message.connectionId, new ArraySegment<byte>(message.bytes), Channels.Unreliable);
unreliableServerToClient.RemoveAt(0);
}
// not enough time elapsed yet
break;
}
// update wrapped transport too
wrap.ServerLateUpdate();
}
public override int GetBatchThreshold(int channelId) => wrap.GetBatchThreshold(channelId);
public override int GetMaxPacketSize(int channelId = 0) => wrap.GetMaxPacketSize(channelId);
public override void Shutdown() => wrap.Shutdown();
public override string ToString() => $"{nameof(LatencySimulation)} {wrap}";
}
}