added vram memory access, minor optimizations for volume hacks (#236)

* minor optimization: changed user_volume type to avoid unnecessary casting (#21)

* minor refactoring for better performances

* added vram memory access

---------

Co-authored-by: eadmaster <51NMBsFda0ab1>

Author: eadmaster

libretro.cpp

@@ -2613,6 +2613,8 @@ void *retro_get_memory_data(unsigned type)
          return (uint8_t*)SaveRAM;
       case RETRO_MEMORY_SYSTEM_RAM:
          return BaseRAM;
+      case RETRO_MEMORY_VIDEO_RAM:
+         return vdc->VRAM;
       default:
          break;
    }
@@ -2630,6 +2632,8 @@ size_t retro_get_memory_size(unsigned type)
          return 2048;
       case RETRO_MEMORY_SYSTEM_RAM:
          return 8192;
+      case RETRO_MEMORY_VIDEO_RAM:
+         return 65536;
       default:
          break;
    }

mednafen/pce_fast/psg.cpp

@@ -31,7 +31,7 @@ void PCEFast_PSG::SetVolume(double new_volume)
    Blip_Synth_set_volume(&Synth, OutputVolume / 6, 8192);
 }
 
-void PCEFast_PSG::SetChannelUserVolume(int chnum, uint8 new_volume)
+void PCEFast_PSG::SetChannelUserVolume(int chnum, int32 new_volume)
 {
     if(chnum >=6 || new_volume > 100) return;  // check valid args
     psg_channel *ch = &channel[chnum];
@@ -41,13 +41,24 @@ void PCEFast_PSG::SetChannelUserVolume(int chnum, uint8 new_volume)
 void PCEFast_PSG::UpdateOutput_Norm(const int32 timestamp, psg_channel *ch)
 {
    int32 samp[2];
+   int delta0;
+   int delta1;   
    int sv = ch->dda;
 
    samp[0] = dbtable[ch->vl[0]][sv];
    samp[1] = dbtable[ch->vl[1]][sv];
 
-   Blip_Synth_offset(&Synth, timestamp, (samp[0] - ch->blip_prev_samp[0]) * ch->user_volume / 100, sbuf[0]);
-   Blip_Synth_offset(&Synth, timestamp, (samp[1] - ch->blip_prev_samp[1]) * ch->user_volume / 100, sbuf[1]);
+   if(ch->user_volume < 100)
+   {
+       delta0 = (samp[0] - ch->blip_prev_samp[0]) * ch->user_volume / 100;
+       delta1 = (samp[1] - ch->blip_prev_samp[1]) * ch->user_volume / 100;
+   } else {
+       delta0 = samp[0] - ch->blip_prev_samp[0];
+       delta1 = samp[1] - ch->blip_prev_samp[1];
+   }
+    
+   Blip_Synth_offset(&Synth, timestamp, delta0, sbuf[0]);
+   Blip_Synth_offset(&Synth, timestamp, delta1, sbuf[1]);
 
    ch->blip_prev_samp[0] = samp[0];
    ch->blip_prev_samp[1] = samp[1];
@@ -56,13 +67,24 @@ void PCEFast_PSG::UpdateOutput_Norm(const int32 timestamp, psg_channel *ch)
 void PCEFast_PSG::UpdateOutput_Noise(const int32 timestamp, psg_channel *ch)
 {
    int32 samp[2];
+   int delta0;
+   int delta1;
    int sv = ((ch->lfsr & 1) << 5) - (ch->lfsr & 1); //(ch->lfsr & 0x1) ? 0x1F : 0;
 
    samp[0] = dbtable[ch->vl[0]][sv];
    samp[1] = dbtable[ch->vl[1]][sv];
 
-   Blip_Synth_offset(&Synth, timestamp, (samp[0] - ch->blip_prev_samp[0]) * ch->user_volume / 100, sbuf[0]);
-   Blip_Synth_offset(&Synth, timestamp, (samp[1] - ch->blip_prev_samp[1]) * ch->user_volume / 100, sbuf[1]);
+   if(ch->user_volume < 100)
+   {
+       delta0 = (samp[0] - ch->blip_prev_samp[0]) * ch->user_volume / 100;
+       delta1 = (samp[1] - ch->blip_prev_samp[1]) * ch->user_volume / 100;
+   } else {
+       delta0 = samp[0] - ch->blip_prev_samp[0];
+       delta1 = samp[1] - ch->blip_prev_samp[1];
+   }
+    
+   Blip_Synth_offset(&Synth, timestamp, delta0, sbuf[0]);
+   Blip_Synth_offset(&Synth, timestamp, delta1, sbuf[1]);
 
    ch->blip_prev_samp[0] = samp[0];
    ch->blip_prev_samp[1] = samp[1];
@@ -71,11 +93,22 @@ void PCEFast_PSG::UpdateOutput_Noise(const int32 timestamp, psg_channel *ch)
 void PCEFast_PSG::UpdateOutput_Off(const int32 timestamp, psg_channel *ch)
 {
    int32 samp[2];
+   int delta0;
+   int delta1;
 
    samp[0] = samp[1] = 0;
 
-   Blip_Synth_offset(&Synth, timestamp, (samp[0] - ch->blip_prev_samp[0]) * ch->user_volume / 100, sbuf[0]);
-   Blip_Synth_offset(&Synth, timestamp, (samp[1] - ch->blip_prev_samp[1]) * ch->user_volume / 100, sbuf[1]);
+   if(ch->user_volume < 100)
+   {
+       delta0 = (samp[0] - ch->blip_prev_samp[0]) * ch->user_volume / 100;
+       delta1 = (samp[1] - ch->blip_prev_samp[1]) * ch->user_volume / 100;
+   } else {
+       delta0 = samp[0] - ch->blip_prev_samp[0];
+       delta1 = samp[1] - ch->blip_prev_samp[1];
+   }
+    
+   Blip_Synth_offset(&Synth, timestamp, delta0, sbuf[0]);
+   Blip_Synth_offset(&Synth, timestamp, delta1, sbuf[1]);
 
    ch->blip_prev_samp[0] = samp[0];
    ch->blip_prev_samp[1] = samp[1];
@@ -85,12 +118,23 @@ void PCEFast_PSG::UpdateOutput_Off(const int32 timestamp, psg_channel *ch)
 void PCEFast_PSG::UpdateOutput_Accum(const int32 timestamp, psg_channel *ch)
 {
    int32 samp[2];
+   int delta0;
+   int delta1;
 
    samp[0] = ((int32)dbtable_volonly[ch->vl[0]] * ((int32)ch->samp_accum - 496)) >> (8 + 5);
    samp[1] = ((int32)dbtable_volonly[ch->vl[1]] * ((int32)ch->samp_accum - 496)) >> (8 + 5);
 
-   Blip_Synth_offset(&Synth, timestamp, (samp[0] - ch->blip_prev_samp[0]) * ch->user_volume / 100, sbuf[0]);
-   Blip_Synth_offset(&Synth, timestamp, (samp[1] - ch->blip_prev_samp[1]) * ch->user_volume / 100, sbuf[1]);
+   if(ch->user_volume < 100)
+   {
+       delta0 = (samp[0] - ch->blip_prev_samp[0]) * ch->user_volume / 100;
+       delta1 = (samp[1] - ch->blip_prev_samp[1]) * ch->user_volume / 100;
+   } else {
+       delta0 = samp[0] - ch->blip_prev_samp[0];
+       delta1 = samp[1] - ch->blip_prev_samp[1];
+   }
+    
+   Blip_Synth_offset(&Synth, timestamp, delta0, sbuf[0]);
+   Blip_Synth_offset(&Synth, timestamp, delta1, sbuf[1]);
 
    ch->blip_prev_samp[0] = samp[0];
    ch->blip_prev_samp[1] = samp[1];

mednafen/pce_fast/psg.h

@@ -31,7 +31,7 @@ struct psg_channel
    uint16 frequency;       /* Channel frequency */
    uint8 balance;          /* Channel balance */
 
-   uint8 user_volume;
+   int32 user_volume;
 };
 
 class PCEFast_PSG
@@ -47,7 +47,7 @@ class PCEFast_PSG
       void Write(int32 timestamp, uint8 A, uint8 V);
 
       void SetVolume(double new_volume) MDFN_COLD;
-      void SetChannelUserVolume(int chnum, uint8 new_volume) MDFN_COLD;
+      void SetChannelUserVolume(int chnum, int32 new_volume) MDFN_COLD;
 
       void EndFrame(int32 timestamp);