added sound channel disable options (#160)

libretro.cpp

@@ -1199,6 +1199,7 @@ static int turbo_counter[MAX_PLAYERS][MAX_BUTTONS] = {};
 static int Turbo_Delay;
 static int Turbo_Toggling = 1;
 static bool turbo_toggle_alt = false;
+static bool disabled_channels[6] = { false };
 static int turbo_toggle_down[MAX_PLAYERS][MAX_BUTTONS] = {};
 
 static void check_variables(void)
@@ -1320,7 +1321,20 @@ static void check_variables(void)
       if (PCECD_SetSettings(&settings) && log_cb)
          log_cb(RETRO_LOG_INFO, "PCE CD Audio settings changed.\n");
    }
-
+   
+   char pce_disable_sound_channel_base_str[] = "pce_disable_sound_channel_0";
+   var.key = pce_disable_sound_channel_base_str;
+   for (unsigned c = 0; c < 6; c++) {;
+       pce_disable_sound_channel_base_str[26] = c+'0';
+       if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
+       {
+          if (strcmp(var.value, "enabled") == 0)
+             disabled_channels[c] = true;
+          else
+             disabled_channels[c] = false;
+       }
+   }
+ 
    // Set Turbo_Toggling
    var.key = "pce_turbo_toggling";
 
@@ -1470,6 +1484,13 @@ bool retro_load_game(const struct retro_game_info *info)
       descs[i].select = 0xFFFF0000;
       i++;
    }
+   
+   for (unsigned c = 0; c < 6; c++) {
+      if(disabled_channels[c]) 
+          psg->DisableChannel(c);
+      else
+          psg->EnableChannel(c);
+   }
 
    mmaps.descriptors = descs;
    mmaps.num_descriptors = i;
@@ -1697,9 +1718,17 @@ void retro_run(void)
       if(PCE_IsCD){
             psg->SetVolume(0.678 * setting_pce_fast_cdpsgvolume / 100);
       }
+      
+      for (unsigned c = 0; c < 6; c++) {
+          if(disabled_channels[c]) 
+              psg->DisableChannel(c);
+          else
+              psg->EnableChannel(c);
+      }
+
       update_geometry(width, height);
    }
-
+        
    if (resolution_changed)
       update_geometry(width, height);
    video_frames++;

libretro_core_options.h

@@ -318,6 +318,72 @@ struct retro_core_option_definition option_defs_us[] = {
       },
       "100"
    },
+   {
+      "pce_disable_sound_channel_0",
+      "Disable Sound Channel 0",
+      "",
+      {
+          { "disabled", NULL },
+          { "enabled", NULL },
+          { NULL, NULL },
+      },
+      "disabled"
+   },
+   {
+      "pce_disable_sound_channel_1",
+      "Disable Sound Channel 1",
+      "",
+      {
+          { "disabled", NULL },
+          { "enabled", NULL },
+          { NULL, NULL },
+      },
+      "disabled"
+   },
+   {
+      "pce_disable_sound_channel_2",
+      "Disable Sound Channel 2",
+      "",
+      {
+          { "disabled", NULL },
+          { "enabled", NULL },
+          { NULL, NULL },
+      },
+      "disabled"
+   },
+   {
+      "pce_disable_sound_channel_3",
+      "Disable Sound Channel 3",
+      "",
+      {
+          { "disabled", NULL },
+          { "enabled", NULL },
+          { NULL, NULL },
+      },
+      "disabled"
+   },
+   {
+      "pce_disable_sound_channel_4",
+      "Disable Sound Channel 4",
+      "",
+      {
+          { "disabled", NULL },
+          { "enabled", NULL },
+          { NULL, NULL },
+      },
+      "disabled"
+   },
+   {
+      "pce_disable_sound_channel_5",
+      "Disable Sound Channel 5",
+      "",
+      {
+          { "disabled", NULL },
+          { "enabled", NULL },
+          { NULL, NULL },
+      },
+      "disabled"
+   },
    {
       "pce_cdspeed",
       "(CD) CD Speed",

mednafen/pce_fast/psg.cpp

@@ -30,6 +30,25 @@ void PCEFast_PSG::SetVolume(double new_volume)
    Blip_Synth_set_volume(&Synth, OutputVolume / 6, 8192);
 }
 
+
+void PCEFast_PSG::DisableChannel(int chnum)
+{
+   psg_channel *ch = &channel[chnum];
+   if(! ch ) return;
+   //printf("Disabled channel: %d\n", chnum);
+   if(chnum < 6)
+        ch->disabled = 1;
+}
+
+void PCEFast_PSG::EnableChannel(int chnum)
+{
+    //printf("Enabled channel: %d\n", chnum);
+    psg_channel *ch = &channel[chnum];
+    if(! ch ) return;
+    if(chnum < 6)
+        ch->disabled = 0;
+}
+
 void PCEFast_PSG::UpdateOutput_Norm(const int32 timestamp, psg_channel *ch)
 {
    int32 samp[2];
@@ -226,6 +245,8 @@ void PCEFast_PSG::Write(int32 timestamp, uint8 A, uint8 V)
    Update(timestamp);
 
    psg_channel *ch = &channel[select];
+   
+   //if(ch->disabled) return;
 
    //if(A == 0x01 || select == 5)
    // printf("Write Ch: %d %04x %02x, %d\n", select, A, V, timestamp);
@@ -353,6 +374,8 @@ void PCEFast_PSG::RunChannel(int chc, int32 timestamp)
 
    ch->lastts = timestamp;
 
+   if(ch->disabled) return;
+   
    if(!run_time)
       return;
 
@@ -555,6 +578,7 @@ void PCEFast_PSG::Power(const int32 timestamp)
       channel[ch].frequency = 0;
       channel[ch].control = 0x00;
       channel[ch].balance = 0;
+      channel[ch].disabled = 0;
       memset(channel[ch].waveform, 0, 32);
       channel[ch].samp_accum = 0;
 

mednafen/pce_fast/psg.h

@@ -30,6 +30,8 @@ struct psg_channel
 
    uint16 frequency;       /* Channel frequency */
    uint8 balance;          /* Channel balance */
+   
+   bool disabled;
 };
 
 class PCEFast_PSG
@@ -45,6 +47,8 @@ class PCEFast_PSG
       void Write(int32 timestamp, uint8 A, uint8 V);
 
       void SetVolume(double new_volume) MDFN_COLD;
+      void EnableChannel(int chnum) MDFN_COLD;
+      void DisableChannel(int chnum) MDFN_COLD;
 
       void EndFrame(int32 timestamp);