prepare for sample C-4 freq

issue #70

papers/format.md

@@ -285,7 +285,8 @@ size | description
   2  | volume
   2  | pitch
   1  | depth
-  3  | reserved
+  1  | reserved
+  2  | C-4 rate (>=32)
   4  | loop point (>=19)
      | - -1 means no loop
  2?? | sample data (always 16-bit)

src/engine/engine.cpp

@@ -1425,7 +1425,13 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
       sample->depth=reader.readC();
 
       // reserved
-      for (int j=0; j<3; j++) reader.readC();
+      reader.readC();
+
+      if (ds.version>=32) {
+        sample->centerRate=reader.readS();
+      } else {
+        reader.readS();
+      }
 
       if (ds.version>=19) {
         sample->loopStart=reader.readI();
@@ -1757,9 +1763,8 @@ SafeWriter* DivEngine::saveFur() {
     w->writeS(sample->vol);
     w->writeS(sample->pitch);
     w->writeC(sample->depth);
-    for (int j=0; j<3; j++) { // reserved
-      w->writeC(0);
-    }
+    w->writeC(0);
+    w->writeS(sample->centerRate);
     w->writeI(sample->loopStart);
 
     w->write(sample->data,sample->length*2);

src/engine/engine.h

@@ -11,8 +11,8 @@
 #include <map>
 #include <queue>
 
-#define DIV_VERSION "0.5pre2"
-#define DIV_ENGINE_VERSION 31
+#define DIV_VERSION "0.5pre3"
+#define DIV_ENGINE_VERSION 32
 
 enum DivStatusView {
   DIV_STATUS_NOTHING=0,

src/engine/platform/pce.cpp

@@ -20,8 +20,8 @@ void DivPlatformPCE::acquire(short* bufL, short* bufR, size_t start, size_t len)
     // PCM part
     for (int i=0; i<6; i++) {
       if (chan[i].pcm && chan[i].dacSample!=-1) {
-        chan[i].dacPeriod-=6;
-        if (chan[i].dacPeriod<1) {
+        chan[i].dacPeriod+=chan[i].dacRate;
+        if (chan[i].dacPeriod>rate) {
           DivSample* s=parent->song.sample[chan[i].dacSample];
           if (s->rendLength<=0) {
             chan[i].dacSample=-1;
@@ -42,7 +42,7 @@ void DivPlatformPCE::acquire(short* bufL, short* bufR, size_t start, size_t len)
               chan[i].dacSample=-1;
             }
           }
-          chan[i].dacPeriod+=chan[i].dacRate;
+          chan[i].dacPeriod-=rate;
         }
       }
     }
@@ -100,7 +100,11 @@ void DivPlatformPCE::tick() {
     chan[i].std.next();
     if (chan[i].std.hadVol) {
       chan[i].outVol=((chan[i].vol&31)*chan[i].std.vol)>>5;
-      chWrite(i,0x04,0x80|chan[i].outVol);
+      if (chan[i].furnaceDac) {
+        // ignore for now
+      } else {
+        chWrite(i,0x04,0x80|chan[i].outVol);
+      }
     }
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
@@ -132,8 +136,8 @@ void DivPlatformPCE::tick() {
       //DivInstrument* ins=parent->getIns(chan[i].ins);
       chan[i].freq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch,true);
       if (chan[i].furnaceDac) {
-        chan[i].dacRate=chan[i].freq;
-        if (dumpWrites) addWrite(0xffff0001+(i<<8),1789773/chan[i].dacRate);
+        chan[i].dacRate=1789773/chan[i].freq;
+        if (dumpWrites) addWrite(0xffff0001+(i<<8),chan[i].dacRate);
       }
       if (chan[i].freq>4095) chan[i].freq=4095;
       if (chan[i].note>0x5d) chan[i].freq=0x01;
@@ -187,6 +191,7 @@ int DivPlatformPCE::dispatch(DivCommand c) {
             chan[c.chan].note=c.value;
           }
           chan[c.chan].active=true;
+          chan[c.chan].std.init(ins);
           //chan[c.chan].keyOn=true;
           chan[c.chan].furnaceDac=true;
         } else {
@@ -200,10 +205,10 @@ int DivPlatformPCE::dispatch(DivCommand c) {
           }
           chan[c.chan].dacPos=0;
           chan[c.chan].dacPeriod=0;
-          chan[c.chan].dacRate=1789773/parent->song.sample[chan[c.chan].dacSample]->rate;
+          chan[c.chan].dacRate=parent->song.sample[chan[c.chan].dacSample]->rate;
           if (dumpWrites) {
             chWrite(c.chan,0x04,0xdf);
-            addWrite(0xffff0001+(c.chan<<8),1789773/chan[c.chan].dacRate);
+            addWrite(0xffff0001+(c.chan<<8),chan[c.chan].dacRate);
           }
           chan[c.chan].furnaceDac=false;
         }

src/engine/sample.h

@@ -2,7 +2,7 @@
 
 struct DivSample {
   String name;
-  int length, rate, loopStart, loopOffP;
+  int length, rate, centerRate, loopStart, loopOffP;
   signed char vol, pitch;
   unsigned char depth;
   short* data;
@@ -15,6 +15,7 @@ struct DivSample {
     name(""),
     length(0),
     rate(32000),
+    centerRate(8363),
     loopStart(-1),
     loopOffP(0),
     vol(0),

src/gui/gui.cpp

@@ -1882,10 +1882,14 @@ void FurnaceGUI::drawSampleEdit() {
       DivSample* sample=e->song.sample[curSample];
       ImGui::InputText("Name",&sample->name);
       ImGui::Text("Length: %d",sample->length);
-      if (ImGui::SliderInt("Rate",&sample->rate,4000,32000,"%dHz")) {
-        if (sample->rate<4000) sample->rate=4000;
+      if (ImGui::InputInt("Rate (Hz)",&sample->rate,10,200)) {
+        if (sample->rate<100) sample->rate=100;
         if (sample->rate>32000) sample->rate=32000;
       }
+      if (ImGui::InputInt("Pitch of C-4 (Hz)",&sample->centerRate,10,200)) {
+        if (sample->centerRate<100) sample->centerRate=100;
+        if (sample->centerRate>32000) sample->centerRate=32000;
+      }
       ImGui::Text("effective rate: %dHz",e->getEffectiveSampleRate(sample->rate));
       bool doLoop=(sample->loopStart>=0);
       if (ImGui::Checkbox("Loop",&doLoop)) {