From 3696028dbe32518725e78db6804f3a2a90a23eb1 Mon Sep 17 00:00:00 2001
From: "Jake.Stine" <Jake.Stine@a6443dda-0b58-4228-96e9-037be469359c>
Date: Thu, 4 Dec 2008 19:48:10 +0000
Subject: [PATCH] Fixed frameskipping when using a strict framerate setting
 (minfps==maxfps). The setting is ideal for users playing high-fps games as it
 allows you to disable the timestretching on your SPU2 plugin. :)

git-svn-id: http://pcsx2-playground.googlecode.com/svn/trunk@390 a6443dda-0b58-4228-96e9-037be469359c
---
 pcsx2/Counters.c |  8 ++++++--
 pcsx2/GS.cpp     | 21 +++++++++++++++------
 pcsx2/GS.h       |  3 ++-
 pcsx2/Misc.c     | 15 ++++++++++-----
 4 files changed, 33 insertions(+), 14 deletions(-)

diff --git a/pcsx2/Counters.c b/pcsx2/Counters.c
index b096feb05e..4fb478bafa 100644
--- a/pcsx2/Counters.c
+++ b/pcsx2/Counters.c
@@ -115,7 +115,6 @@ void rcntInit() {
 // debug code, used for stats
 int g_nCounters[4];
 static int iFrame = 0;	
-//long iFrameLimitEnable = 1;
 
 #ifndef _WIN32
 #include <sys/time.h>
@@ -327,6 +326,11 @@ void vSyncDebugStuff() {
 #endif
 }
 
+void frameLimitReset()
+{
+	m_iStart = GetCPUTicks();
+}
+
 // Framelimiter - Measures the delta time between calls and stalls until a
 // certain amount of time passes if such time hasn't passed yet.
 // See the GS FrameSkip function for details on why this is here and not in the GS.
@@ -356,7 +360,7 @@ static __forceinline void frameLimit()
 		// Keeps the GS skipper from trying to catch up to a framerate
 		// that the limiter already gave up on.
 
-		gsSyncLimiterStartTime( m_iStart );
+		gsSyncLimiterLostTime( (s32)(m_iStart - uExpectedEnd) );
 		return;
 	}
 
diff --git a/pcsx2/GS.cpp b/pcsx2/GS.cpp
index e13e399675..0c5384c738 100644
--- a/pcsx2/GS.cpp
+++ b/pcsx2/GS.cpp
@@ -1660,7 +1660,7 @@ void gifMFIFOInterrupt()
 	cpuRegs.interrupt &= ~(1 << 11);
 }
 
-extern "C" void gsSyncLimiterStartTime( u64 startTime )
+extern "C" void gsSyncLimiterLostTime( s32 deltaTime )
 {
 	// This sync issue applies only to configs that are trying to maintain
 	// a perfect "specific" framerate (where both min and max fps are the same)
@@ -1672,17 +1672,17 @@ extern "C" void gsSyncLimiterStartTime( u64 startTime )
 
 	if( CHECK_MULTIGS )
 	{
-		const u32* stp = (u32*)&startTime;
+		//const u32* stp = (u32*)&startTime;
 		GSRingBufSimplePacket(
 			GS_RINGTYPE_STARTTIME,
-			stp[0],
-			stp[1],
+			deltaTime,
+			0,
 			0
 		);
 	}
 	else
 	{
-		m_iSlowStart = startTime;
+		m_iSlowStart += deltaTime;
 		//m_justSkipped = false;
 	}
 }
@@ -1847,6 +1847,15 @@ extern "C" void gsResetFrameSkip()
 		_resetFrameskip();
 }
 
+extern "C" void frameLimitReset();
+extern "C" void gsDynamicSkipEnable()
+{
+	if( !m_StrictSkipping ) return;
+
+	gsWaitGS();
+	m_iSlowStart = GetCPUTicks();	
+	frameLimitReset();
+}
 
 GS_THREADPROC
 {
@@ -2030,7 +2039,7 @@ GS_THREADPROC
 				break;
 
 				case GS_RINGTYPE_STARTTIME:
-					m_iSlowStart = *(u64*)(g_pGSRingPos+4);
+					m_iSlowStart += *(u32*)(g_pGSRingPos+4);
 					//m_justSkipped = false;
 				break;
 
diff --git a/pcsx2/GS.h b/pcsx2/GS.h
index 8a7ff01867..e857550898 100644
--- a/pcsx2/GS.h
+++ b/pcsx2/GS.h
@@ -81,7 +81,8 @@ void gsShutdown();
 void gsReset();
 void gsSetVideoRegionType( u32 isPal );
 void gsResetFrameSkip();
-void gsSyncLimiterStartTime( u64 startTime );
+void gsSyncLimiterLostTime( s32 deltaTime );
+void gsDynamicSkipEnable();
 
 // mem and size are the ones from GSRingBufCopy
 extern void GSRINGBUF_DONECOPY(const u8 *mem, u32 size);
diff --git a/pcsx2/Misc.c b/pcsx2/Misc.c
index 2e04a213c5..a59380aa1f 100644
--- a/pcsx2/Misc.c
+++ b/pcsx2/Misc.c
@@ -881,22 +881,23 @@ void ProcessFKeys(int fkey, int shift)
 		case 4:
 		{
 			const char* limitMsg;
+			u32 newOptions;
 #ifdef PCSX2_NORECBUILD
             SysPrintf("frame skipping only valid for recompiler build\n");
 #else
 			// cycle
             if( shift ) {
                 // previous
-                Config.Options = (Config.Options&~PCSX2_FRAMELIMIT_MASK)|(((Config.Options&PCSX2_FRAMELIMIT_MASK)+PCSX2_FRAMELIMIT_VUSKIP)&PCSX2_FRAMELIMIT_MASK);
+                newOptions = (Config.Options&~PCSX2_FRAMELIMIT_MASK)|(((Config.Options&PCSX2_FRAMELIMIT_MASK)+PCSX2_FRAMELIMIT_VUSKIP)&PCSX2_FRAMELIMIT_MASK);
             }
             else {
                 // next
-                Config.Options = (Config.Options&~PCSX2_FRAMELIMIT_MASK)|(((Config.Options&PCSX2_FRAMELIMIT_MASK)+PCSX2_FRAMELIMIT_LIMIT)&PCSX2_FRAMELIMIT_MASK);
+                newOptions = (Config.Options&~PCSX2_FRAMELIMIT_MASK)|(((Config.Options&PCSX2_FRAMELIMIT_MASK)+PCSX2_FRAMELIMIT_LIMIT)&PCSX2_FRAMELIMIT_MASK);
             }
 
 			gsResetFrameSkip();
 
-			switch(CHECK_FRAMELIMIT) {
+			switch(newOptions & PCSX2_FRAMELIMIT_MASK) {
 				case PCSX2_FRAMELIMIT_NORMAL:
 					limitMsg = "None/Normal";
 					break;
@@ -907,17 +908,21 @@ void ProcessFKeys(int fkey, int shift)
 				case PCSX2_FRAMELIMIT_VUSKIP:
 					if( GSsetFrameSkip == NULL )
 					{
-						Config.Options &= ~PCSX2_FRAMELIMIT_MASK;
+						newOptions &= ~PCSX2_FRAMELIMIT_MASK;
 						SysPrintf("Notice: GS Plugin does not support frameskipping.\n");
 						limitMsg = "None/Normal";
 					}
 					else
 					{
-						limitMsg = (CHECK_FRAMELIMIT == PCSX2_FRAMELIMIT_SKIP) ? "Skip" : "VUSkip";
+						// When enabling Skipping we have to make sure Skipper (GS) and Limiter (EE)
+						// are properly synchronized.
+						gsDynamicSkipEnable();
+						limitMsg = ((newOptions & PCSX2_FRAMELIMIT_MASK) == PCSX2_FRAMELIMIT_SKIP) ? "Skip" : "VUSkip";
 					}
 
 					break;
 			}
+			InterlockedExchange( &Config.Options, newOptions );
 
 			SysPrintf("Frame Limit Mode Changed: %s\n", limitMsg );