Ticket #3309: t3309_cap_expected_simTime_v3.patch

source/network/NetTurnManager.cpp

@@ -77 +77 @@
     m_CurrentTurn = newCurrentTurn;
     m_ReadyTurn = newReadyTurn;
     m_DeltaSimTime = 0;
     size_t queuedCommandsSize = m_QueuedCommands.size();
     m_QueuedCommands.clear();
     m_QueuedCommands.resize(queuedCommandsSize);
 }
 
 void CNetTurnManager::SetPlayerID(int playerId)
 {
     m_PlayerId = playerId;
 }
 
 bool CNetTurnManager::WillUpdate(float simFrameLength)
 {
     // Keep this in sync with the return value of Update()
 
     if (m_DeltaSimTime + simFrameLength < 0)
         return false;
 
     if (m_ReadyTurn <= m_CurrentTurn)
         return false;
 
     return true;
 }
 
 bool CNetTurnManager::Update(float simFrameLength, size_t maxTurns)
 {
     m_DeltaSimTime += simFrameLength;
 
+    // If the game becomes laggy, m_DeltaSimTime increases progressively.
+    // The engine will fast forward accordingly to catch up.
+    // To keep the game playable, stop fast forwarding after 2 turn lengths.
+    m_DeltaSimTime = std::min(m_DeltaSimTime, 2.0f * m_TurnLength / 1000.0f);
+
     // If we haven't reached the next turn yet, do nothing
     if (m_DeltaSimTime < 0)
         return false;
 
     NETTURN_LOG((L"Update current=%d ready=%d\n", m_CurrentTurn, m_ReadyTurn));
 
     // Check that the next turn is ready for execution
     if (m_ReadyTurn <= m_CurrentTurn)
     {
         // Oops, we wanted to start the next turn but it's not ready yet -
         // there must be too much network lag.
         // TODO: complain to the user.
         // TODO: send feedback to the server to increase the turn length.
 
         // Reset the next-turn timer to 0 so we try again next update but
         // so we don't rush to catch up in subsequent turns.
         // TODO: we should do clever rate adjustment instead of just pausing like this.
         m_DeltaSimTime = 0;
 
         return false;
     }
 
     maxTurns = std::max((size_t)1, maxTurns); // always do at least one turn
 
     for (size_t i = 0; i < maxTurns; ++i)
     {
         // Check that we've reached the i'th next turn
         if (m_DeltaSimTime < 0)
             break;