Make interpolation config a little cleaner.

Add config file option to all ports.

apu/apu.cpp

@@ -914,11 +914,3 @@ bool8 S9xSPCDump (const char *filename)
 
 	return (TRUE);
 }
-
-extern int dsp_interpolation_method;
-
-void S9xSetDSPInterpolation (int mode)
-{
-	dsp_interpolation_method = mode;
-	return;
-}

apu/apu.h

@@ -237,6 +237,4 @@ void S9xUpdateDynamicRate (int, int);
 #define DSP_INTERPOLATION_CUBIC    3
 #define DSP_INTERPOLATION_SINC     4
 
-void S9xSetDSPInterpolation (int);
-
 #endif

apu/bapu/dsp/SPC_DSP.cpp

@@ -1,5 +1,7 @@
 // snes_spc 0.9.0. http://www.slack.net/~ant/
 
+#include "snes9x.h"
+
 #include "SPC_DSP.h"
 
 #include "blargg_endian.h"
@@ -412,14 +414,12 @@ static short const sinc [2048] =
    -38,    41,  -328,   718, 15642,   613,  -302,    38,
 };
 
-int dsp_interpolation_method = 2;
-
 inline int SPC_DSP::interpolate( voice_t const* v )
 {
     int out;
     int const* in = &v->buf [(v->interp_pos >> 12) + v->buf_pos];
 
-    switch (dsp_interpolation_method)
+    switch (Settings.InterpolationMethod)
     {
     case 0: // raw
     {

gtk/src/gtk_config.cpp

@@ -257,6 +257,7 @@ Snes9xConfig::load_defaults (void)
     Settings.SoundSync = 1;
     Settings.DynamicRateControl = FALSE;
     Settings.DynamicRateLimit = 5;
+    Settings.InterpolationMethod = DSP_INTERPOLATION_GAUSSIAN;
     Settings.HDMATimingHack = 100;
     Settings.SuperFXClockMultiplier = 100;
     Settings.InitialSnapshotFilename[0] = '\0';
@@ -409,6 +410,7 @@ Snes9xConfig::save_config_file (void)
     xml_out_int (xml, "dynamic_rate_control", Settings.DynamicRateControl);
     xml_out_int (xml, "dynamic_rate_limit", Settings.DynamicRateLimit);
     xml_out_int (xml, "auto_input_rate", auto_input_rate);
+    xml_out_int (xml, "interpolation_method", Settings.InterpolationMethod);
 
     /* Snes9X core-stored variables */
     xml_out_int (xml, "transparency", Settings.Transparency);
@@ -917,6 +919,10 @@ Snes9xConfig::set_option (const char *name, const char *value)
     {
         rewind_granularity = CLAMP (atoi (value), 0, 600);
     }
+    else if (!strcasecmp (name, "interpolation_method"))
+    {
+        Settings.InterpolationMethod = CLAMP (atoi (value), 0, 4);
+    }
     else
     {
         fprintf (stderr, _("bad option name: %s\n"), name);

libretro/libretro.cpp

@@ -169,6 +169,7 @@ void retro_set_environment(retro_environment_t cb)
         { "snes9x_up_down_allowed", "Allow Opposing Directions; disabled|enabled" },
         { "snes9x_overclock_superfx", "SuperFX Overclocking; 100%|150%|200%|250%|300%|350%|400%|450%|500%|50%" },
         { "snes9x_hires_blend", "Hires Blending; disabled|enabled" },
+        { "snes9x_audio_interpolation", "Audio Interpolation; gaussian|cubic|sinc|none|linear" },
         { "snes9x_layer_1", "Show layer 1; enabled|disabled" },
         { "snes9x_layer_2", "Show layer 2; enabled|disabled" },
         { "snes9x_layer_3", "Show layer 3; enabled|disabled" },
@@ -313,6 +314,24 @@ static void update_variables(void)
     var.value=NULL;
     Settings.SupportHiRes=!(environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && !strcmp("disabled", var.value));
 
+    var.key="snes9x_audio_interpolation";
+    var.value=NULL;
+    if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
+    {
+        if (strcmp(var.value, "gaussian") == 0)
+            Settings.InterpolationMethod = DSP_INTERPOLATION_GAUSSIAN;
+        else if (strcmp(var.value, "linear") == 0)
+            Settings.InterpolationMethod = DSP_INTERPOLATION_LINEAR;
+        else if (strcmp(var.value, "cubic") == 0)
+            Settings.InterpolationMethod = DSP_INTERPOLATION_CUBIC;
+        else if (strcmp(var.value, "sinc") == 0)
+            Settings.InterpolationMethod = DSP_INTERPOLATION_SINC;
+        else if (strcmp(var.value, "none") == 0)
+            Settings.InterpolationMethod = DSP_INTERPOLATION_NONE;
+    }
+    else
+        Settings.InterpolationMethod = DSP_INTERPOLATION_GAUSSIAN;
+
     var.key = "snes9x_overscan";
 
     if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)

snes9x.cpp

@@ -428,6 +428,7 @@ void S9xLoadConfigFiles (char **argv, int argc)
 	Settings.Mute                       =  conf.GetBool("Sound::Mute",                         false);
 	Settings.DynamicRateControl         =  conf.GetBool("Sound::DynamicRateControl",           false);
 	Settings.DynamicRateLimit           =  conf.GetInt ("Sound::DynamicRateLimit",             5);
+	Settings.InterpolationMethod        =  conf.GetInt ("Sound::InterpolationMethod",          2);
 
 	// Display
 

snes9x.h

@@ -419,6 +419,7 @@ struct SSettings
 	bool8	Mute;
 	bool8	DynamicRateControl;
 	int32	DynamicRateLimit; /* Multiplied by 1000 */
+	int32	InterpolationMethod;
 
 	bool8	SupportHiRes;
 	bool8	Transparency;

win32/wconfig.cpp

@@ -1005,6 +1005,7 @@ void WinRegisterConfigItems()
 	AddBoolC("Mute", GUI.Mute, false, "true to mute sound output (does not disable the sound CPU)");
 	AddBool("DynamicRateControl", Settings.DynamicRateControl, false);
 	AddBool("AutomaticInputRate", GUI.AutomaticInputRate, true);
+	AddIntC("InterpolationMethod", Settings.InterpolationMethod, 2, "0 = None, 1 = Linear, 2 = Gaussian (accurate), 3 = Cubic, 4 = Sinc");
 #undef CATEGORY
 #define	CATEGORY "Sound\\Win"
 	AddUIntC("SoundDriver", GUI.SoundDriver, 4, "0=Snes9xDirectSound, 4=XAudio2 (recommended)");