more fixes to auto-LT

the biggest problem was that it would use the local player's latencyTolerance setting as the max value instead of what the server sent over. This could result in weird stuff happening when the LT started changing. Also, a value of 0 or less is ignored in case somebody unknowingly tries to force it to go faster than it can.
avaraline · Feb 20, 2025 · 16a239a · 16a239a
1 parent fb75f26
commit 16a239a
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Showing 3 changed files with 20 additions and 11 deletions.
diff --git a/src/game/CNetManager.cpp b/src/game/CNetManager.cpp
@@ -815,16 +815,18 @@ void CNetManager::AutoLatencyControl(FrameNumber frameNumber, Boolean didWait) {
 
                 // Usually maxFrameLatency is determined primarily by maxRoundTripLatency...
                 // but addOneLatency helps account for deficiencies in the calculation by measuring how often clients had to wait too long for packets to arrive
-                short maxFrameLatency = addOneLatency + itsGame->RoundTripToFrameLatency(maxRoundTripLatency);
+                short newFrameLatency = addOneLatency + itsGame->RoundTripToFrameLatency(maxRoundTripLatency);
 
-                // treat kLatencyToleranceTag as upper limit when in AutoLT mode
-                maxFrameLatency = std::min<short>(maxFrameLatency, gApplication->Get<double>(kLatencyToleranceTag)/itsGame->fpsScale);
+                // limit LT unless it's set to zero
+                if (maxAutoLatency > 0) {
+                    newFrameLatency = std::min<short>(newFrameLatency, maxAutoLatency);
+                }
 
                 DBG_Log("lt", "  fn=%d RTT=%d, Classic LT=%.2lf, add=%lf --> FL=%d\n",
                         frameNumber, maxRoundTripLatency,
-                        (maxRoundTripLatency) / (2.0*CLASSICFRAMETIME), addOneLatency*itsGame->fpsScale, maxFrameLatency);
+                        (maxRoundTripLatency) / (2.0*CLASSICFRAMETIME), addOneLatency*itsGame->fpsScale, newFrameLatency);
 
-                itsGame->SetFrameLatency(maxFrameLatency, 2, maxPlayer);
+                itsGame->SetFrameLatency(newFrameLatency, 2, maxPlayer);
             }
 
             ResetLatencyVote();
@@ -1298,8 +1300,17 @@ void CNetManager::DoConfig(short senderSlot) {
     if (PermissionQuery(kAllowLatencyBit, 0) || !(activePlayersDistribution & kdServerOnly) || senderSlot == 0) {
         // transmitting latencyTolerance in terms of frameLatency to keep it as a short value on transmission
         itsGame->SetFrameTime(theConfig->frameTime);
-        itsGame->SetFrameLatency(theConfig->frameLatency, -1);
-        SDL_Log("DoConfig LT = %lf\n", itsGame->latencyTolerance);
+        maxAutoLatency = theConfig->frameLatency;
+        short initFrameLatency = theConfig->frameLatency;
+        if (IsAutoLatencyEnabled()) {
+            // try setting initial FL from max local RTT value, maybe need the server to send this?  we'll see
+            initFrameLatency = itsGame->RoundTripToFrameLatency(itsCommManager->GetMaxRoundTrip(AlivePlayersDistribution()));
+            if (maxAutoLatency > 0) {
+                initFrameLatency = std::min<short>(initFrameLatency, maxAutoLatency);
+            }
+        }
+        itsGame->SetFrameLatency(initFrameLatency, -1);
+        SDL_Log("DoConfig LT = %lf, FL = %d\n", itsGame->latencyTolerance, maxAutoLatency);
         itsGame->SetSpawnOrder((SpawnOrder)theConfig->spawnOrder);
         latencyVoteFrame = itsGame->NextFrameForPeriod(AUTOLATENCYPERIOD);
     }
@@ -1310,9 +1321,6 @@ void CNetManager::UpdateLocalConfig() {
 
     config.frameLatency = gApplication
         ? gApplication->Get<float>(kLatencyToleranceTag) / itsGame->fpsScale : 0;
-    if (IsAutoLatencyEnabled()) {
-        config.frameLatency = std::min<short>(config.frameLatency, itsGame->initialFrameLatency);
-    }
     config.frameTime = itsGame->frameTime;
     config.spawnOrder = gApplication ? gApplication->Get<short>(kSpawnOrder) : ksHybrid;
     config.hullType = gApplication ? gApplication->Number(kHullTypeTag) : 0;

diff --git a/src/game/CNetManager.h b/src/game/CNetManager.h
@@ -96,6 +96,7 @@ class CNetManager : public CDirectObject {
 
     short serverOptions;
     short loaderSlot;
+    short maxAutoLatency;  // max frame latency for auto-LT
 
     PlayerConfigRecord config {};
 

diff --git a/src/gui/Preferences.h b/src/gui/Preferences.h
@@ -105,7 +105,7 @@ static json defaultPrefs = {
     // {kJoystickModeTag, false},
     {kInvertYAxisTag, false},
     {kMouseSensitivityTag, 0},
-    {kLatencyToleranceTag, 1.0},
+    {kLatencyToleranceTag, 2.5},  // 2.5 = max for auto latency
     {kHullTypeTag, 0}, // 0 = light, 1 = medium, 2 = heavy
     {kServerOptionsTag, 129}, // 1 = allow load, 128 = auto latency
     {kDefaultUDPPort, 19567},