Gamestate snapshots (#8819)

* Add initial interface.

* Implement move operator in MemoryStream

* Add pod array serialisation traits.

* Add push_back with move semantics to CircularBuffer

* Initial implementation of GameStateSnapshots

* Add GameStateSnapshots to Context.

* Add mp_desync console command.

* Compare sprite data and fill change list.

* Minor changes.

* Proof of concept.

* Calculate offset instead of using offsetof

* Implement game state difference detection

* Update mp_desync console command.

* Fix identification of sprite remove/add.

* Fix crash when only one peep in park when using mp_desync

* Output state differences into user directory desync folder.

* Add desync debugging as an option.

* Add information to network status when a desync report was created.

* Cast to proper type for %llu.

* Update xcode project

* Add more information to the diffed data.

* Remove client-only relevant fields.

* Cleanup.

* Add better name output for misc sprites

* Add srand0 and tick information to the output

* Bump up network version

* Cleanup

* Set desync_debugging to false as default

* Apply suggestions

src/openrct2/GameState.cpp

@@ -12,9 +12,11 @@
 #include "Context.h"
 #include "Editor.h"
 #include "Game.h"
+#include "GameStateSnapshots.h"
 #include "Input.h"
 #include "OpenRCT2.h"
 #include "ReplayManager.h"
+#include "config/Config.h"
 #include "interface/Screenshot.h"
 #include "localisation/Date.h"
 #include "localisation/Localisation.h"
@@ -238,13 +240,30 @@ void GameState::UpdateLogic()
 
     if (network_get_mode() == NETWORK_MODE_SERVER)
     {
+        if (network_gamestate_snapshots_enabled())
+        {
+            CreateStateSnapshot();
+        }
+
         // Send current tick out.
         network_send_tick();
     }
     else if (network_get_mode() == NETWORK_MODE_CLIENT)
     {
         // Check desync.
-        network_check_desynchronization();
+        bool desynced = network_check_desynchronisation();
+        if (desynced)
+        {
+            // If desync debugging is enabled and we are still connected request the specific game state from server.
+            if (network_gamestate_snapshots_enabled() && network_get_status() == NETWORK_STATUS_CONNECTED)
+            {
+                // Create snapshot from this tick so we can compare it later
+                // as we won't pause the game on this event.
+                CreateStateSnapshot();
+
+                network_request_gamestate_snapshot();
+            }
+        }
     }
 
     date_update();
@@ -311,3 +330,12 @@ void GameState::UpdateLogic()
     gScenarioTicks++;
     gSavedAge++;
 }
+
+void GameState::CreateStateSnapshot()
+{
+    IGameStateSnapshots* snapshots = GetContext()->GetGameStateSnapshots();
+
+    auto& snapshot = snapshots->CreateSnapshot();
+    snapshots->Capture(snapshot);
+    snapshots->LinkSnapshot(snapshot, gCurrentTicks, scenario_rand_state().s0);
+}