feat(replay): Check CRC messages from all players in replays.

Author: Caball009

GeneralsMD/Code/GameEngine/Include/Common/GlobalData.h

@@ -367,6 +367,8 @@ class GlobalData : public SubsystemInterface
 	Bool m_afterIntro;								///< we need to tell the game our intro is done
 	Bool m_allowExitOutOfMovies;			///< flag to allow exit out of movies only after the Intro has played
 
+	Bool m_replayOnlyCheckLocalPlayer; ///< flag to check only the CRC messages from the player that recorded a replay
+
 	Bool m_loadScreenRender;						///< flag to disallow rendering of almost everything during a loadscreen
 
 	Real m_keyboardScrollFactor;			///< Factor applied to game scrolling speed via keyboard scrolling

GeneralsMD/Code/GameEngine/Include/Common/Player.h

@@ -221,7 +221,7 @@ class Player : public Snapshot
 
 	void deletePlayerAI();
 
-	UnicodeString getPlayerDisplayName() { return m_playerDisplayName; }
+	UnicodeString getPlayerDisplayName() const { return m_playerDisplayName; }
 	NameKeyType getPlayerNameKey() const { return m_playerNameKey; }
 
 	AsciiString getSide() const { return m_side; }

GeneralsMD/Code/GameEngine/Include/Common/Recorder.h

@@ -53,7 +53,61 @@ enum RecorderModeType CPP_11(: Int) {
 	RECORDERMODETYPE_NONE // this is a valid state to be in on the shell map, or in saved games
 };
 
-class CRCInfo;
+// TheSuperHackers @info helmutbuhler 03/04/2025
+// Some info about CRC:
+// In each game, each peer periodically calculates a CRC from the local gamestate and sends that
+// in a message to all peers (including itself) so that everyone can check that the crc is synchronous.
+// In a network game, there is a delay between sending the CRC message and receiving it. This is
+// necessary because if you were to wait each frame for all messages from all peers, things would go
+// horribly slow.
+// But this delay is not a problem for CRC checking because everyone receives the CRC in the same frame
+// and every peer just makes sure all the received CRCs are equal.
+// While playing replays, this is a problem however: The CRC messages in the replays appear on the frame
+// they were received, which can be a few frames delayed if it was a network game. And if we were to
+// compare those with the local gamestate, they wouldn't sync up.
+// So, in order to fix this, we need to queue up our local CRCs,
+// so that we can check it with the crc messages that come later.
+// This class is basically that queue.
+class CRCInfo
+{
+public:
+	struct MismatchData
+	{
+		MismatchData() :
+			mismatched(FALSE),
+			playerIndex(0),
+			queueSize(0),
+			playbackCRC(0),
+			playerCRC(0)
+		{}
+
+		Bool mismatched;
+		Byte playerIndex;
+		UnsignedShort queueSize;
+		UnsignedInt playbackCRC;
+		UnsignedInt playerCRC;
+	};
+
+	CRCInfo();
+	void init(Bool isMultiplayer, Int localPlayerIndex);
+	void addPlaybackCRC(UnsignedInt val);
+	void addPlayerCRC(Int playerIndex, UnsignedInt val);
+	void setSawCRCMismatch();
+	Bool sawCRCMismatch() const;
+	Byte getLocalPlayerIndex() const;
+	MismatchData getMismatchData();
+
+	static Int getPlayerIndexOffset();
+
+protected:
+	UnsignedInt getLargestPlayerQueueSize() const;
+
+	Bool m_skippedOne;
+	Bool m_sawCRCMismatch;
+	Byte m_localPlayerIndex;
+	std::list<UnsignedInt> m_playbackData;
+	std::list<UnsignedInt> m_playerData[MAX_SLOTS];
+};
 
 class RecorderClass : public SubsystemInterface {
 public:
@@ -84,10 +138,12 @@ class RecorderClass : public SubsystemInterface {
 #endif
 	Bool isPlaybackInProgress() const;
 
-public:
-	void handleCRCMessage(UnsignedInt newCRC, Int playerIndex, Bool fromPlayback);
+	void handlePlaybackCRCMessage(UnsignedInt newCRC);
+	void handlePlayerCRCMessage(Int playerIndex, UnsignedInt newCRC);
+	void checkForMismatch();
+
 protected:
-	CRCInfo *m_crcInfo;
+	CRCInfo m_crcInfo;
 public:
 
 	// read in info relating to a replay, conditionally setting up m_file for playback

GeneralsMD/Code/GameEngine/Include/GameLogic/GameLogic.h

@@ -293,6 +293,13 @@ class GameLogic : public SubsystemInterface, public Snapshot
 
 private:
 
+	enum CRCValidationMode CPP_11(: UnsignedByte)
+	{
+		CRCMODE_NONE,
+		CRCMODE_NETWORK,
+		CRCMODE_REPLAY,
+	};
+
 	/**
 		overrides to thing template buildable status. doesn't really belong here,
 		but has to go somewhere. (srj)
@@ -312,7 +319,7 @@ class GameLogic : public SubsystemInterface, public Snapshot
 	// CRC cache system -----------------------------------------------------------------------------
 	UnsignedInt	m_CRC;																			///< Cache of previous CRC value
 	std::map<Int, UnsignedInt> m_cachedCRCs;								///< CRCs we've seen this frame
-	Bool m_shouldValidateCRCs;															///< Should we validate CRCs this frame?
+	CRCValidationMode m_shouldValidateCRCs;									///< Should we validate CRCs this frame?
 	//-----------------------------------------------------------------------------------------------
 	//Bool m_loadingScene;
 	Bool m_loadingMap;

GeneralsMD/Code/GameEngine/Source/Common/CommandLine.cpp

@@ -465,6 +465,13 @@ Int parseJobs(char *args[], int num)
 	return 1;
 }
 
+Int parseReplayCRC(char* args[], int num)
+{
+	TheWritableGlobalData->m_replayOnlyCheckLocalPlayer = TRUE;
+
+	return 1;
+}
+
 Int parseXRes(char *args[], int num)
 {
 	if (num > 1)
@@ -1177,6 +1184,9 @@ static CommandLineParam paramsForEngineInit[] =
 	// TheSuperHackers @feature xezon 03/08/2025 Force full viewport for 'Control Bar Pro' Addons like GenTool did it.
 	{ "-forcefullviewport", parseFullViewport },
 
+	// TheSuperHackers @feature Caball009 24/04/2026 Enable checking only the CRC messages from the player that recorded a replay.
+	{ "-replayLocalPlayerCRC", parseReplayCRC },
+
 #if defined(RTS_DEBUG)
 	{ "-noaudio", parseNoAudio },
 	{ "-map", parseMapName },

GeneralsMD/Code/GameEngine/Source/Common/GlobalData.cpp

@@ -1009,6 +1009,7 @@ GlobalData::GlobalData()
 	m_playSizzle = TRUE;
 	m_afterIntro = FALSE;
 	m_allowExitOutOfMovies = FALSE;
+	m_replayOnlyCheckLocalPlayer = FALSE;
 	m_loadScreenRender = FALSE;
 
 	m_keyboardDefaultScrollFactor = m_keyboardScrollFactor = 0.5f;