Adding Gaussian interpolation to SPU

This function can be enabled as an option in the SPU settings

Gamecube/GamecubeMain.cpp

@@ -85,6 +85,7 @@ void LidInterrupt();
 void CheckPsxType();
 void psxResetRcntRate();
 void plugin_call_rearmed_cbs(unsigned long autoDwActFixes, int cfgUseDithering);
+void setSpuInterpolation(int spuInterpolation);
 }
 
 u32* xfb[3] = { NULL, NULL, NULL };	/*** Framebuffers ***/
@@ -108,7 +109,7 @@ char frameLimit[2];
 char frameSkip;
 char useDithering;
 extern char audioEnabled;
-char volume;
+char spuInterpolation;
 char showFPSonScreen;
 char printToScreen;
 char menuActive;
@@ -163,7 +164,7 @@ static struct {
 	char  min, max;
 } OPTIONS[] =
 { { "Audio", &audioEnabled, AUDIO_DISABLE, AUDIO_ENABLE },
-  { "Volume", &volume, VOLUME_LOUDEST, VOLUME_LOW },
+  { "Interpolation", &spuInterpolation, SIMPLE_INTERPOLATION, GAUSSI_INTERPOLATION },
   { "FPS", &showFPSonScreen, FPS_HIDE, FPS_SHOW },
 //  { "Debug", &printToScreen, DEBUG_HIDE, DEBUG_SHOW },
   { "ScreenMode", &screenMode, SCREENMODE_4x3, SCREENMODE_16x9_PILLARBOX },
@@ -331,7 +332,7 @@ void loadSettings(int argc, char *argv[])
 {
 	// Default Settings
 	audioEnabled     = 1; // Audio
-	volume           = VOLUME_MEDIUM;
+	spuInterpolation = SIMPLE_INTERPOLATION;
 #ifdef RELEASE
 	showFPSonScreen  = 0; // Don't show FPS on Screen
 #else
@@ -376,7 +377,6 @@ void loadSettings(int argc, char *argv[])
 	Config.Xa = 0;  //XA enabled
 	Config.Cdda = 0; //CDDA enabled
 	Config.cycle_multiplier = CYCLE_MULT_DEFAULT;
-	iVolume = volume; //Volume="medium" in PEOPSspu
 	Config.PsxAuto = 1; //Autodetect
 	LoadCdBios = BOOTTHRUBIOS_NO;
 	lang = 0;
@@ -433,7 +433,7 @@ void loadSettings(int argc, char *argv[])
 	//Synch settings with Config
 	Config.Cpu=dynacore;
 	//iUseDither = useDithering;
-	iVolume = volume;
+	setSpuInterpolation(spuInterpolation);
 }
 
 void ScanPADSandReset(u32 dummy)

Gamecube/menu/SettingsFrame.cpp

@@ -143,6 +143,7 @@ FILE* IplFont_getFontFile(char* sdUsb);
 void psxResetRcntRate();
 void pl_chg_psxtype(int is_pal_);
 void gpuChangePsxType();
+void setSpuInterpolation(int spuInterpolation);
 }
 
 #define NUM_FRAME_BUTTONS 64
@@ -238,9 +239,9 @@ static char FRAME_STRINGS[79][24] =
 	  "Disable Audio",
 	  "Disable XA",
 	  "Disable CDDA",
-	  "Volume",
-	  "loudest",	//iVolume=1
-	  "loud",
+	  "Interpolation",
+	  "Simple",	//iVolume=1
+	  "Gaussi",
 	  "medium",
 	  "low",		//iVolume=4
 	//Strings for Saves tab (starting at FRAME_STRINGS[51]) ..was[55]
@@ -640,18 +641,12 @@ void SettingsFrame::activateSubmenu(int submenu)
 			else								FRAME_BUTTONS[42].button->setSelected(true);
 			if (Config.Cdda == CDDA_DISABLE)	FRAME_BUTTONS[43].button->setSelected(true);
 			else								FRAME_BUTTONS[44].button->setSelected(true);
-			FRAME_BUTTONS[45].buttonString = FRAME_STRINGS[46+iVolume];
+			FRAME_BUTTONS[45].buttonString = FRAME_STRINGS[46 + spuInterpolation];
 			for (int i = 39; i < 46; i++)
 			{
 				FRAME_BUTTONS[i].button->setVisible(true);
 				FRAME_BUTTONS[i].button->setActive(true);
 			}
-			// upd xjsxjs197 start
-			/*for (int i = 43; i <= 44; i++)	//disable CDDA buttons
-			{
-				FRAME_BUTTONS[i].button->setActive(false);
-			}*/
-			// upd xjsxjs197 end
 			break;
 		case SUBMENU_SAVES:
 			setDefaultFocus(FRAME_BUTTONS[4].button);
@@ -1669,16 +1664,18 @@ void Func_DisableCddaNo()
 	//menu::MessageBox::getInstance().setMessage("CDDA audio is not implemented");
 }
 
-extern "C" void SetVolume(void);
-
 void Func_VolumeToggle()
 {
-	iVolume--;
-	if (iVolume<1)
-		iVolume = 4;
-	FRAME_BUTTONS[45].buttonString = FRAME_STRINGS[46+iVolume];
-	volume = iVolume;
-	SetVolume();
+	if (spuInterpolation == SIMPLE_INTERPOLATION)
+	{
+		spuInterpolation = GAUSSI_INTERPOLATION;
+	}
+	else
+	{
+		spuInterpolation = SIMPLE_INTERPOLATION;
+	}
+	FRAME_BUTTONS[45].buttonString = FRAME_STRINGS[46 + spuInterpolation];
+	setSpuInterpolation(spuInterpolation);
 }
 
 void Func_MemcardSaveSD()

Gamecube/wiiSXconfig.h

@@ -44,14 +44,11 @@ enum ConfigCdda //Config.Cdda
 	CDDA_DISABLE
 };
 
-extern int iVolume;
-extern char volume;
-enum iVolume
-{
-	VOLUME_LOUDEST=1,
-	VOLUME_LOUD,
-	VOLUME_MEDIUM,
-	VOLUME_LOW
+extern char spuInterpolation;
+enum spuInterpolationEnum
+{
+	SIMPLE_INTERPOLATION = 1,
+	GAUSSI_INTERPOLATION,
 };
 
 extern char showFPSonScreen;