Revert "Partially revert revision d511b506120c."

This reverts commit 08e06b22937fa79db165e5a31dfd4ccf67ef57db.

1 files changed, 92 insertions, 13 deletions

diff --git a/Source/Core/VideoCommon/Src/PixelShaderGen.cpp b/Source/Core/VideoCommon/Src/PixelShaderGen.cpp
index 7500997fef..bc7a12304f 100644
--- a/Source/Core/VideoCommon/Src/PixelShaderGen.cpp
+++ b/Source/Core/VideoCommon/Src/PixelShaderGen.cpp
@@ -487,6 +487,15 @@ static char swapModeTable[4][5];
 static char text[16384];
 static bool DepthTextureEnable;
 
+struct RegisterState
+{
+	bool ColorNeedOverflowControl;
+	bool AlphaNeedOverflowControl;
+	bool AuxStored;
+};
+
+static RegisterState RegisterStates[4];
+
 static void BuildSwapModeTable()
 {
 	static const char *swapColors = "rgba";
@@ -717,6 +726,16 @@ const char *GeneratePixelShaderCode(DSTALPHA_MODE dstAlphaMode, API_TYPE ApiType
 		}
 	}
 
+	RegisterStates[0].AlphaNeedOverflowControl = false;
+	RegisterStates[0].ColorNeedOverflowControl = false;
+	RegisterStates[0].AuxStored = false;
+	for(int i = 1; i < 4; i++)
+	{
+		RegisterStates[i].AlphaNeedOverflowControl = true;
+		RegisterStates[i].ColorNeedOverflowControl = true;
+		RegisterStates[i].AuxStored = false;
+	}
+
 	for (int i = 0; i < numStages; i++)
 		WriteStage(p, i, ApiType); //build the equation for this stage
 
@@ -724,11 +743,22 @@ const char *GeneratePixelShaderCode(DSTALPHA_MODE dstAlphaMode, API_TYPE ApiType
 	{
 		// The results of the last texenv stage are put onto the screen,
 		// regardless of the used destination register
-		WRITE(p, "prev.rgb = %s;\n",tevCOutputTable[bpmem.combiners[numStages-1].colorC.dest]);
-		WRITE(p, "prev.a = %s;\n",tevAOutputTable[bpmem.combiners[numStages-1].alphaC.dest]);
+		if(bpmem.combiners[numStages - 1].colorC.dest != 0)
+		{
+			bool retrieveFromAuxRegister = !RegisterStates[bpmem.combiners[numStages - 1].colorC.dest].ColorNeedOverflowControl && RegisterStates[bpmem.combiners[numStages - 1].colorC.dest].AuxStored;
+			WRITE(p, "prev.rgb = %s%s;\n", retrieveFromAuxRegister ? "c" : "" , tevCOutputTable[bpmem.combiners[numStages - 1].colorC.dest]);
+			RegisterStates[0].ColorNeedOverflowControl = RegisterStates[bpmem.combiners[numStages - 1].colorC.dest].ColorNeedOverflowControl;
+		}
+		if(bpmem.combiners[numStages - 1].alphaC.dest != 0)
+		{
+			bool retrieveFromAuxRegister = !RegisterStates[bpmem.combiners[numStages - 1].alphaC.dest].AlphaNeedOverflowControl && RegisterStates[bpmem.combiners[numStages - 1].alphaC.dest].AuxStored;
+			WRITE(p, "prev.a = %s%s;\n", retrieveFromAuxRegister ? "c" : "" , tevAOutputTable[bpmem.combiners[numStages - 1].alphaC.dest]);
+			RegisterStates[0].AlphaNeedOverflowControl = RegisterStates[bpmem.combiners[numStages - 1].alphaC.dest].AlphaNeedOverflowControl;
+		}
 	}
-	// emulation of unsigned 8 overflow when casting
-	WRITE(p, "prev = frac(4.0f + prev * (255.0f/256.0f)) * (256.0f/255.0f);\n");
+	// emulation of unsigned 8 overflow when casting if needed
+	if(RegisterStates[0].AlphaNeedOverflowControl || RegisterStates[0].ColorNeedOverflowControl)
+		WRITE(p, "prev = frac(prev * (255.0f/256.0f)) * (256.0f/255.0f);\n");
 
 	if(Pretest ==  -1)
 	{
@@ -917,7 +947,6 @@ static void WriteStage(char *&p, int n, API_TYPE ApiType)
 	TevStageCombiner::ColorCombiner &cc = bpmem.combiners[n].colorC;
 	TevStageCombiner::AlphaCombiner &ac = bpmem.combiners[n].alphaC;
 
-	// blah1
 	if(cc.a == TEVCOLORARG_RASA || cc.a == TEVCOLORARG_RASC
 		|| cc.b == TEVCOLORARG_RASA || cc.b == TEVCOLORARG_RASC
 		|| cc.c == TEVCOLORARG_RASA || cc.c == TEVCOLORARG_RASC
@@ -950,7 +979,6 @@ static void WriteStage(char *&p, int n, API_TYPE ApiType)
 		WRITE(p, "textemp = float4(1.0f, 1.0f, 1.0f, 1.0f);\n");
 
 
-	// blah2
 	if (cc.a == TEVCOLORARG_KONST || cc.b == TEVCOLORARG_KONST || cc.c == TEVCOLORARG_KONST || cc.d == TEVCOLORARG_KONST
 		|| ac.a == TEVALPHAARG_KONST || ac.b == TEVALPHAARG_KONST || ac.c == TEVALPHAARG_KONST || ac.d == TEVALPHAARG_KONST)
 	{
@@ -971,30 +999,78 @@ static void WriteStage(char *&p, int n, API_TYPE ApiType)
 		|| cc.b == TEVCOLORARG_CPREV || cc.b == TEVCOLORARG_APREV
 		|| cc.c == TEVCOLORARG_CPREV || cc.c == TEVCOLORARG_APREV
 		|| ac.a == TEVALPHAARG_APREV || ac.b == TEVALPHAARG_APREV || ac.c == TEVALPHAARG_APREV)
-		WRITE(p, "cprev = frac(prev * (255.0f/256.0f)) * (256.0f/255.0f);\n");
-
+	{
+		if(RegisterStates[0].AlphaNeedOverflowControl || RegisterStates[0].ColorNeedOverflowControl)
+		{
+			WRITE(p, "cprev = frac(prev * (255.0f/256.0f)) * (256.0f/255.0f);\n");
+			RegisterStates[0].AlphaNeedOverflowControl = false;
+			RegisterStates[0].ColorNeedOverflowControl = false;
+		}
+		else
+		{
+			WRITE(p, "cprev = prev;\n");
+		}
+		RegisterStates[0].AuxStored = true;
+	}
 
 	if(cc.a == TEVCOLORARG_C0 || cc.a == TEVCOLORARG_A0
 	|| cc.b == TEVCOLORARG_C0 || cc.b == TEVCOLORARG_A0
 	|| cc.c == TEVCOLORARG_C0 || cc.c == TEVCOLORARG_A0
 	|| ac.a == TEVALPHAARG_A0 || ac.b == TEVALPHAARG_A0 || ac.c == TEVALPHAARG_A0)
-		WRITE(p, "cc0 = frac(c0 * (255.0f/256.0f)) * (256.0f/255.0f);\n");
-
+	{
+		if(RegisterStates[1].AlphaNeedOverflowControl || RegisterStates[1].ColorNeedOverflowControl)
+		{
+			WRITE(p, "cc0 = frac(c0 * (255.0f/256.0f)) * (256.0f/255.0f);\n");
+			RegisterStates[1].AlphaNeedOverflowControl = false;
+			RegisterStates[1].ColorNeedOverflowControl = false;
+		}
+		else
+		{
+			WRITE(p, "cc0 = c0;\n");
+		}
+		RegisterStates[1].AuxStored = true;
+	}
 
 	if(cc.a == TEVCOLORARG_C1 || cc.a == TEVCOLORARG_A1
 	|| cc.b == TEVCOLORARG_C1 || cc.b == TEVCOLORARG_A1
 	|| cc.c == TEVCOLORARG_C1 || cc.c == TEVCOLORARG_A1
 	|| ac.a == TEVALPHAARG_A1 || ac.b == TEVALPHAARG_A1 || ac.c == TEVALPHAARG_A1)
-		WRITE(p, "cc1 = frac(c1 * (255.0f/256.0f)) * (256.0f/255.0f);\n");
-
+	{
+		if(RegisterStates[2].AlphaNeedOverflowControl || RegisterStates[2].ColorNeedOverflowControl)
+		{
+			WRITE(p, "cc1 = frac(c1 * (255.0f/256.0f)) * (256.0f/255.0f);\n");
+			RegisterStates[2].AlphaNeedOverflowControl = false;
+			RegisterStates[2].ColorNeedOverflowControl = false;
+		}
+		else
+		{
+			WRITE(p, "cc1 = c1;\n");
+		}
+		RegisterStates[2].AuxStored = true;
+	}
 
 	if(cc.a == TEVCOLORARG_C2 || cc.a == TEVCOLORARG_A2
 	|| cc.b == TEVCOLORARG_C2 || cc.b == TEVCOLORARG_A2
 	|| cc.c == TEVCOLORARG_C2 || cc.c == TEVCOLORARG_A2
 	|| ac.a == TEVALPHAARG_A2 || ac.b == TEVALPHAARG_A2 || ac.c == TEVALPHAARG_A2)
+	{
+		if(RegisterStates[3].AlphaNeedOverflowControl || RegisterStates[3].ColorNeedOverflowControl)
+		{
 			WRITE(p, "cc2 = frac(c2 * (255.0f/256.0f)) * (256.0f/255.0f);\n");
+			RegisterStates[3].AlphaNeedOverflowControl = false;
+			RegisterStates[3].ColorNeedOverflowControl = false;
+		}
+		else
+		{
+			WRITE(p, "cc2 = c2;\n");
+		}
+		RegisterStates[3].AuxStored = true;
+	}
 
+	RegisterStates[cc.dest].ColorNeedOverflowControl = (cc.clamp == 0);
+	RegisterStates[cc.dest].AuxStored = false;
 
+	// combine the color channel
 	WRITE(p, "// color combine\n");
 	if (cc.clamp)
 		WRITE(p, "%s = saturate(", tevCOutputTable[cc.dest]);
@@ -1042,8 +1118,11 @@ static void WriteStage(char *&p, int n, API_TYPE ApiType)
 		WRITE(p, ")");
 	WRITE(p,";\n");
 
-	WRITE(p, "// alpha combine\n");
+	RegisterStates[ac.dest].AlphaNeedOverflowControl = (ac.clamp == 0);
+	RegisterStates[ac.dest].AuxStored = false;
+
 	// combine the alpha channel
+	WRITE(p, "// alpha combine\n");
 	if (ac.clamp)
 		WRITE(p, "%s = saturate(", tevAOutputTable[ac.dest]);
 	else