Added netplay client frame throttling functionality to keep it in step with server.

src/drivers/Qt/NetPlay.cpp

@@ -71,13 +71,14 @@ struct NetPlayFrameDataHist_t
 	int getLast( NetPlayFrameData& out )
 	{
 		int i;
-		if (bufHead == 0)
+		const int head = bufHead;
+		if (head == 0)
 		{
 			i = numFrames - 1;
 		}
 		else
 		{
-			i = bufHead - 1;
+			i = head - 1;
 		}
 		out = data[i];
 
@@ -87,17 +88,18 @@ struct NetPlayFrameDataHist_t
 	int find( uint32_t frame, NetPlayFrameData& out )
 	{
 		int i, retval = -1;
+		const int head = bufHead;
 
-		if (bufHead == 0)
+		if (head == 0)
 		{
 			i = numFrames - 1;
 		}
 		else
 		{
-			i = bufHead - 1;
+			i = head - 1;
 		}
 
-		while (i != bufHead)
+		while (i != head)
 		{
 			if (data[i].frameNum == frame)
 			{
@@ -173,6 +175,10 @@ NetPlayServer::NetPlayServer(QObject *parent)
 
 	connect(consoleWindow, SIGNAL(romLoaded(void)), this, SLOT(onRomLoad(void)));
 	connect(consoleWindow, SIGNAL(nesResetOccurred(void)), this, SLOT(onNesReset(void)));
+
+	FCEU_WRAPPER_LOCK();
+	inputFrameCount = static_cast<uint32_t>(currFrameCounter);
+	FCEU_WRAPPER_UNLOCK();
 }
 
 
@@ -417,6 +423,10 @@ void NetPlayServer::onRomLoad()
 {
 	//printf("New ROM Loaded!\n");
 	FCEU_WRAPPER_LOCK();
+
+	inputClear();
+	inputFrameCount = static_cast<uint32_t>(currFrameCounter);
+
 	// New ROM has been loaded by server, signal clients to load and sync
 	for (auto& client : clientList )
 	{
@@ -430,6 +440,10 @@ void NetPlayServer::onNesReset()
 {
 	//printf("New ROM Loaded!\n");
 	FCEU_WRAPPER_LOCK();
+
+	inputClear();
+	inputFrameCount = static_cast<uint32_t>(currFrameCounter);
+
 	// NES Reset has occurred on server, signal clients sync
 	for (auto& client : clientList )
 	{
@@ -663,7 +677,7 @@ void NetPlayServer::update(void)
 	const uint32_t maxLead = maxLeadFrames;
 	const uint32_t currFrame = static_cast<uint32_t>(currFrameCounter);
 	const uint32_t leadFrame = currFrame + maxLead;
-	const uint32_t lastFrame = inputFrameBack();
+	//const uint32_t lastFrame = inputFrameBack();
 	uint32_t lagFrame = 0;
 	uint8_t  localGP[4] = { 0 };
 	uint8_t  gpData[4] = { 0 };
@@ -735,7 +749,7 @@ void NetPlayServer::update(void)
 		}
 	}
 
-	hostRdyFrame = ( (currFrame > lastFrame) || (lastFrame == 0) );
+	hostRdyFrame = (currFrame >= inputFrameCount);
 
 	shouldRunFrame = (clientMinFrame != 0xFFFFFFFF) && 
 		(clientMinFrame >= lagFrame ) &&
@@ -752,6 +766,7 @@ void NetPlayServer::update(void)
 		clientWaitCounter = 0;
 	}
 
+	//printf("Host Frame: Run:%u   Input:%u   Last:%u\n", currFrame, inputFrameCount, lastFrame);
 	//printf("Client Frame: Min:%u  Max:%u\n", clientMinFrame, clientMaxFrame);
 
 	if (shouldRunFrame)
@@ -760,7 +775,7 @@ void NetPlayServer::update(void)
 		NetPlayFrameInput  inputFrame;
 		netPlayRunFrameReq  runFrameReq;
 
-		inputFrame.frameCounter = static_cast<uint32_t>(currFrameCounter) + 1;
+		inputFrame.frameCounter = ++inputFrameCount;
 		inputFrame.ctrl[0] = gpData[0];
 		inputFrame.ctrl[1] = gpData[1];
 		inputFrame.ctrl[2] = gpData[2];
@@ -772,6 +787,13 @@ void NetPlayServer::update(void)
 		runFrameReq.ctrlState[2] = inputFrame.ctrl[2];
 		runFrameReq.ctrlState[3] = inputFrame.ctrl[3];
 
+		uint32_t  catchUpThreshold = maxLead;
+		if (catchUpThreshold < 3)
+		{
+			catchUpThreshold = 3;
+		}
+		runFrameReq.catchUpThreshold = catchUpThreshold;
+
 		pushBackInput( inputFrame );
 
 		runFrameReq.toNetworkByteOrder();
@@ -1109,15 +1131,21 @@ int NetPlayClient::readMessages( void (*msgCallback)( void *userData, void *msgB
 	{
 		bool readReq;
 		netPlayMsgHdr *hdr;
-		const int netPlayMsgHdrSize = sizeof(netPlayMsgHdr);
+		constexpr int netPlayMsgHdrSize = sizeof(netPlayMsgHdr);
+		FCEU::timeStampRecord ts;
 
-		readReq = sock->bytesAvailable() > 0;
+		ts.readNew();
+		int bytesAvailable = sock->bytesAvailable();
+		readReq = bytesAvailable > 0;
+
+		//printf("Read Bytes Available: %lu  %i\n", ts.toMilliSeconds(), bytesAvailable);
 
 		while (readReq)
 		{
 			if (recvMsgBytesLeft > 0)
 			{
-				readReq = (sock->bytesAvailable() >= recvMsgBytesLeft);
+				bytesAvailable = sock->bytesAvailable();
+				readReq = (bytesAvailable >= recvMsgBytesLeft);
 
 				if (readReq)
 				{
@@ -1135,16 +1163,18 @@ int NetPlayClient::readMessages( void (*msgCallback)( void *userData, void *msgB
 
 					if (recvMsgBytesLeft > 0)
 					{
-						readReq = (sock->bytesAvailable() >= recvMsgBytesLeft);
+						bytesAvailable = sock->bytesAvailable();
+						readReq = (bytesAvailable >= recvMsgBytesLeft);
 					}
 					else
 					{
 						msgCallback( userData, recvMsgBuf, recvMsgSize );
-						readReq = (sock->bytesAvailable() > 0);
+						bytesAvailable = sock->bytesAvailable();
+						readReq = (bytesAvailable > 0);
 					}
 				}
 			}
-			else if (sock->bytesAvailable() >= netPlayMsgHdrSize)
+			else if (bytesAvailable >= netPlayMsgHdrSize)
 			{
 				sock->read( recvMsgBuf, netPlayMsgHdrSize );
 
@@ -1166,7 +1196,8 @@ int NetPlayClient::readMessages( void (*msgCallback)( void *userData, void *msgB
 				{
 					msgCallback( userData, recvMsgBuf, recvMsgSize );
 				}
-				readReq = (sock->bytesAvailable() >= recvMsgSize);
+				bytesAvailable = sock->bytesAvailable();
+				readReq = (bytesAvailable >= recvMsgSize);
 			}
 			else
 			{
@@ -1269,10 +1300,20 @@ void NetPlayClient::clientProcessMessage( void *msgBuf, size_t msgSize )
 			inputFrame.ctrl[2] = msg->ctrlState[2];
 			inputFrame.ctrl[3] = msg->ctrlState[3];
 
-			if (inputFrame.frameCounter > inputFrameBack())
+			catchUpThreshold   = msg->catchUpThreshold;
+
+			uint32_t lastInputFrame = inputFrameBack();
+			uint32_t currFrame = static_cast<uint32_t>(currFrameCounter);
+
+			if (inputFrame.frameCounter > lastInputFrame)
 			{
 				pushBackInput( inputFrame );
 			}
+			else
+			{
+				printf("Drop Frame: LastRun:%u   LastInput:%u   NewInput:%u\n", currFrame, lastInputFrame, inputFrame.frameCounter);
+			}
+			//printf("Run Frame: LastRun:%u   LastInput:%u   NewInput:%u\n", currFrame, lastInputFrame, inputFrame.frameCounter);
 		}
 		break;
 		case NETPLAY_PING_REQ:
@@ -1302,6 +1343,8 @@ NetPlayHostDialog::NetPlayHostDialog(QWidget *parent)
 	QVBoxLayout *mainLayout;
 	QHBoxLayout *hbox;
 	QGridLayout *grid;
+	QGroupBox   *networkGroupBox;
+	QGroupBox   *settingsGroupBox;
 	QPushButton *cancelButton, *startButton;
 	QLabel *lbl;
 
@@ -1310,8 +1353,18 @@ NetPlayHostDialog::NetPlayHostDialog(QWidget *parent)
 	setWindowTitle("NetPlay Host Game");
 
 	mainLayout = new QVBoxLayout();
+	networkGroupBox = new QGroupBox(tr("Network Setup"));
+	settingsGroupBox = new QGroupBox(tr("Server Settings"));
+	hbox = new QHBoxLayout();
 	grid = new QGridLayout();
 
+	mainLayout->addLayout(hbox);
+	hbox->addWidget(networkGroupBox);
+	hbox->addWidget(settingsGroupBox);
+
+	// Network Settings 
+	networkGroupBox->setLayout(grid);
+
 	lbl = new QLabel( tr("Server Name:") );
 	grid->addWidget( lbl, 0, 0 );
 
@@ -1350,7 +1403,22 @@ NetPlayHostDialog::NetPlayHostDialog(QWidget *parent)
 	passwordEntry = new QLineEdit();
 	grid->addWidget( passwordEntry, 4, 1 );
 
-	mainLayout->addLayout(grid);
+	// Misc Settings 
+	grid = new QGridLayout();
+	settingsGroupBox->setLayout(grid);
+
+	lbl = new QLabel( tr("Max Frame Lead:") );
+	frameLeadSpinBox = new QSpinBox();
+	frameLeadSpinBox->setRange(5,60);
+	frameLeadSpinBox->setValue(30);
+	grid->addWidget( lbl, 0, 0, 1, 1 );
+	grid->addWidget( frameLeadSpinBox, 0, 1, 1, 1 );
+
+	allowClientRomReqCBox = new QCheckBox(tr("Allow Client ROM Load Requests"));
+	grid->addWidget( allowClientRomReqCBox, 1, 0, 1, 2 );
+
+	allowClientStateReqCBox = new QCheckBox(tr("Allow Client State Load Requests"));
+	grid->addWidget( allowClientStateReqCBox, 2, 0, 1, 2 );
 
 	startButton = new QPushButton( tr("Start") );
 	startButton->setIcon(style()->standardIcon(QStyle::SP_DialogApplyButton));
@@ -1406,6 +1474,9 @@ void NetPlayHostDialog::onStartClicked(void)
 	server->setRole( playerRoleBox->currentData().toInt() );
 	server->sessionName = sessionNameEntry->text();
 	server->sessionPasswd = passwordEntry->text();
+	server->setMaxLeadFrames( frameLeadSpinBox->value() );
+	server->setAllowClientRomLoadRequest( allowClientRomReqCBox->isChecked() );
+	server->setAllowClientStateLoadRequest( allowClientStateReqCBox->isChecked() );
 
 	bool listenSucceeded = server->listen( QHostAddress::Any, netPort );
 
@@ -1503,6 +1574,7 @@ NetPlayJoinDialog::NetPlayJoinDialog(QWidget *parent)
 
 	passwordEntry = new QLineEdit();
 	passwordEntry->setMaxLength(64);
+	passwordEntry->setEnabled(false);
 	grid->addWidget( passwordEntry, 4, 1 );
 
 	mainLayout->addLayout(grid);
@@ -1944,7 +2016,7 @@ bool NetPlaySkipWait(void)
 
 	if (client)
 	{
-		skip = client->inputAvailable() > 1;
+		skip = client->inputAvailableCount() > client->catchUpThreshold;
 	}
 	return skip;
 }

src/drivers/Qt/NetPlay.h

@@ -139,6 +139,8 @@ class NetPlayServer : public QTcpServer
 
 		uint32_t getMaxLeadFrames(){ return maxLeadFrames; }
 		void setMaxLeadFrames(uint32_t value){ maxLeadFrames = value; }
+		void setAllowClientRomLoadRequest(bool value){ allowClientRomLoadReq = value; }
+		void setAllowClientStateLoadRequest(bool value){ allowClientStateLoadReq = value; }
 
 		void serverProcessMessage( NetPlayClient *client, void *msgBuf, size_t msgSize );
 
@@ -161,7 +163,9 @@ class NetPlayServer : public QTcpServer
 		uint32_t cycleCounter = 0;
 		uint32_t maxLeadFrames = 10u;
 		uint32_t clientWaitCounter = 0;
+		uint32_t inputFrameCount = 0;
 		bool     allowClientRomLoadReq = true;
+		bool     allowClientStateLoadReq = true;
 
 	public:
 	signals:
@@ -203,12 +207,18 @@ class NetPlayClient : public QObject
 		int  readMessages( void (*msgCallback)( void *userData, void *msgBuf, size_t msgSize ), void *userData );
 		void clientProcessMessage( void *msgBuf, size_t msgSize );
 
-		size_t inputAvailable(void)
+		bool inputAvailable(void)
 		{
 			FCEU::autoScopedLock alock(inputMtx);
 		       	return !input.empty();
 		};
 
+		size_t inputAvailableCount(void)
+		{
+			FCEU::autoScopedLock alock(inputMtx);
+		       	return input.size();
+		};
+
 		void pushBackInput( NetPlayFrameInput &in )
 		{
 			FCEU::autoScopedLock alock(inputMtx);
@@ -264,6 +274,8 @@ class NetPlayClient : public QObject
 		bool    syncOk = false;
 		unsigned int currentFrame = 0;
 		unsigned int readyFrame = 0;
+		unsigned int catchUpThreshold = 10;
+		unsigned int tailTarget = 3;
 		uint8_t gpData[4];
 
 	private:
@@ -319,6 +331,9 @@ protected:
 	QComboBox  *playerRoleBox;
 	QLineEdit  *passwordEntry;
 	QCheckBox  *passwordRequiredCBox;
+	QSpinBox   *frameLeadSpinBox;
+	QCheckBox  *allowClientRomReqCBox;
+	QCheckBox  *allowClientStateReqCBox;
 
 	static NetPlayHostDialog* instance;
 

src/drivers/Qt/NetPlayMsgDef.h

@@ -252,9 +252,10 @@ struct netPlayRunFrameReq
 	uint32_t  flags;
 	uint32_t  frameNum;
 	uint8_t   ctrlState[4];
+	uint8_t   catchUpThreshold;
 
 	netPlayRunFrameReq(void)
-		: hdr(NETPLAY_RUN_FRAME_REQ, sizeof(netPlayRunFrameReq)), flags(0), frameNum(0) 
+		: hdr(NETPLAY_RUN_FRAME_REQ, sizeof(netPlayRunFrameReq)), flags(0), frameNum(0), catchUpThreshold(10)
 	{
 		memset( ctrlState, 0, sizeof(ctrlState) );
 	}

src/drivers/Qt/sdl-throttle.cpp

@@ -65,6 +65,8 @@ bool useIntFrameRate = false;
 static double frmRateAdjRatio = 1.000000f; // Frame Rate Adjustment Ratio
 extern bool turbo;
 
+int NetPlayThrottleControl();
+
 double getHighPrecTimeStamp(void)
 {
 	double t;
@@ -373,6 +375,7 @@ SpeedThrottle(void)
 	// If Emulator is paused, don't waste CPU cycles spinning on nothing.
 	if ( !isEmuPaused && ((g_fpsScale >= 32) || turboActive) )
 	{
+		//printf("Skip Wait\n");
 		return 0; /* Done waiting */
 	}
 	FCEU::timeStampRecord cur_time, idleStart, time_left;
@@ -502,6 +505,8 @@ SpeedThrottle(void)
 			//printf("Frame Delta: %f us   min:%f   max:%f \n", frameDelta * 1e6, frameDeltaMin * 1e6, frameDeltaMax * 1e6 );
 			//printf("Frame Sleep Time: %f   Target Error: %f us\n", time_left * 1e6, (cur_time - Nexttime) * 1e6 );
 		}
+		NetPlayThrottleControl();
+
 		Lasttime = Nexttime;
 		Nexttime = Lasttime + DesiredFrameTime;
 		Latetime = Nexttime + HalfFrameTime;
@@ -512,6 +517,7 @@ SpeedThrottle(void)
 			Nexttime = Lasttime + DesiredFrameTime;
 			Latetime = Nexttime + HalfFrameTime;
 		}
+
 		return 0; /* Done waiting */
 	}
 
@@ -570,6 +576,64 @@ int CustomEmulationSpeed(int spdPercent)
    return 0;
 }
 
+int NetPlayThrottleControl()
+{
+	NetPlayClient *client = NetPlayClient::GetInstance();
+
+	if (client)
+	{
+		uint32_t inputAvailCount = client->inputAvailableCount();
+		const uint32_t tailTarget = client->tailTarget;
+
+		double targetDelta = static_cast<double>( static_cast<intptr_t>(inputAvailCount) - static_cast<intptr_t>(tailTarget) );
+
+		// Simple linear FPS scaling adjustment based on target error.
+		constexpr double speedUpSlope = (0.05) / (10.0);
+		double newScale = 1.0 + (targetDelta * speedUpSlope);
+
+		if (newScale != g_fpsScale)
+		{
+			double hz;
+			int32_t fps = FCEUI_GetDesiredFPS(); // Do >> 24 to get in Hz
+			int32_t T;
+
+			g_fpsScale = newScale;
+
+			hz = ( ((double)fps) / 16777216.0 );
+
+			desired_frametime = 1.0 / ( hz * g_fpsScale );
+
+			if ( useIntFrameRate )
+			{
+				hz = (double)( (int)(hz) );
+
+				frmRateAdjRatio = (1.0 / ( hz * g_fpsScale )) / desired_frametime;
+
+				//printf("frameAdjRatio:%f \n", frmRateAdjRatio );
+			}
+			else
+			{
+				frmRateAdjRatio = 1.000000f;
+			}
+			desired_frametime = 1.0 / ( hz * g_fpsScale );
+			desired_frameRate = ( hz * g_fpsScale );
+			baseframeRate = hz;
+
+			T = (int32_t)( desired_frametime * 1000.0 );
+
+			if ( T < 0 ) T = 1;
+
+			DesiredFrameTime.fromSeconds( desired_frametime );
+			HalfFrameTime = DesiredFrameTime / 2;
+			QuarterFrameTime = DesiredFrameTime / 4;
+			DoubleFrameTime = DesiredFrameTime * 2;
+		}
+		//printf("NetPlayCPUThrottle: %f   %f    %f  Target:%u  InputAvail:%u\n", newScale, desired_frameRate, targetDelta, tailTarget, inputAvailCount);
+	}
+
+   return 0;
+}
+
 
 /**
  * Set the emulation speed throttling to a specific value.