implement panning slide and panbrello effects

doc/3-pattern/effects.md

@@ -74,6 +74,13 @@ not all chips support these effects.
   - `00` is left.
   - `80` is center.
   - `FF` is right.
+  - ---
+- `83xy`: **Panning slide.**
+  - if `y` is 0 then this pans to the left by `x` each tick.
+  - if `x` is 0 then this pans to the right by `y` each tick.
+  - be noted that panning macros override this effect.
+- `84xy`: **Panbrello.** makes panning oscillate. `x` is the speed, while `y` is the depth.
+  - be noted that panning macros override this effect.
 
 ## time
 

src/engine/engine.cpp

@@ -83,6 +83,10 @@ const char* DivEngine::getEffectDesc(unsigned char effect, int chan, bool notNul
       return _("81xx: Set panning (left channel)");
     case 0x82:
       return _("82xx: Set panning (right channel)");
+    case 0x83:
+      return _("83xy: Panning slide (x0: left; 0y: right)");
+    case 0x84:
+      return _("84xy: Panbrello (x: speed; y: depth)");
     case 0x88:
       return _("88xy: Set panning (rear channels; x: left; y: right)");
       break;

src/engine/engine.h

@@ -137,6 +137,7 @@ struct DivChannelState {
   int delayOrder, delayRow, retrigSpeed, retrigTick;
   int vibratoDepth, vibratoRate, vibratoPos, vibratoPosGiant, vibratoShape, vibratoFine;
   int tremoloDepth, tremoloRate, tremoloPos;
+  int panDepth, panRate, panPos, panSpeed;
   int sampleOff;
   unsigned char arp, arpStage, arpTicks, panL, panR, panRL, panRR, lastVibrato, lastPorta, cutType;
   bool doNote, legato, portaStop, keyOn, keyOff, nowYouCanStop, stopOnOff, releasing;
@@ -174,6 +175,10 @@ struct DivChannelState {
     tremoloDepth(0),
     tremoloRate(0),
     tremoloPos(0),
+    panDepth(0),
+    panRate(0),
+    panPos(0),
+    panSpeed(0),
     sampleOff(0),
     arp(0),
     arpStage(-1),

src/engine/playback.cpp

@@ -686,6 +686,31 @@ void DivEngine::processRow(int i, bool afterDelay) {
         chan[i].panR=effectVal;
         panChanged=true;
         break;
+      case 0x83: // pan slide
+        if (effectVal!=0) {
+          if ((effectVal&15)!=0) {
+            chan[i].panSpeed=(effectVal&15);
+          } else {
+            chan[i].panSpeed=(effectVal>>4);
+          }
+          // panbrello and slides are incompatible
+          chan[i].panDepth=0;
+          chan[i].panRate=0;
+          chan[i].panPos=0;
+        } else {
+          chan[i].panSpeed=0;
+        }
+        break;
+      case 0x84: // panbrello
+        if (chan[i].panDepth==0) {
+          chan[i].panPos=0;
+        }
+        chan[i].panDepth=effectVal&15;
+        chan[i].panRate=effectVal>>4;
+        if (chan[i].panDepth!=0) {
+          chan[i].panSpeed=0;
+        }
+        break;
       case 0x88: // panning rear (split 4-bit)
         chan[i].panRL=(effectVal>>4)|(effectVal&0xf0);
         chan[i].panRR=(effectVal&15)|((effectVal&15)<<4);
@@ -1536,11 +1561,14 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
       }
       // process stuff
       if (!shallStop) for (int i=0; i<chans; i++) {
+        // delay effects
         if (chan[i].rowDelay>0) {
           if (--chan[i].rowDelay==0) {
             processRow(i,true);
           }
         }
+
+        // retrigger
         if (chan[i].retrigSpeed) {
           if (--chan[i].retrigTick<0) {
             chan[i].retrigTick=chan[i].retrigSpeed-1;
@@ -1548,6 +1576,8 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
             keyHit[i]=true;
           }
         }
+
+        // volume slides and tremolo
         if (!song.noSlidesOnFirstTick || !firstTick) {
           if (chan[i].volSpeed!=0) {
             chan[i].volume=(chan[i].volume&0xff)|(dispatchCmd(DivCommand(DIV_CMD_GET_VOLUME,i))<<8);
@@ -1577,6 +1607,63 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
             dispatchCmd(DivCommand(DIV_CMD_VOLUME,i,MAX(0,chan[i].volume-(tremTable[chan[i].tremoloPos]*chan[i].tremoloDepth))>>8));
           }
         }
+
+        // panning slides
+        // TODO: UNTESTED... can't test right now
+        if (chan[i].panSpeed!=0) {
+          int newPanL=chan[i].panL;
+          int newPanR=chan[i].panR;
+          if (chan[i].panSpeed>0) { // right
+            if (newPanR>=0xff) {
+              newPanL-=chan[i].panSpeed;
+            } else {
+              newPanR+=chan[i].panSpeed;
+            }
+          } else { // left
+            if (newPanL>=0xff) {
+              newPanR+=chan[i].panSpeed;
+            } else {
+              newPanL-=chan[i].panSpeed;
+            }
+          }
+
+          if (newPanL<0) newPanL=0;
+          if (newPanL>0xff) newPanL=0xff;
+          if (newPanR<0) newPanR=0;
+          if (newPanR>0xff) newPanR=0xff;
+
+          chan[i].panL=newPanL;
+          chan[i].panR=newPanR;
+
+          dispatchCmd(DivCommand(DIV_CMD_PANNING,i,chan[i].panL,chan[i].panR));
+        } else if (chan[i].panDepth>0) {
+          chan[i].panPos+=chan[i].panRate;
+          chan[i].panPos&=255;
+
+          // calculate...
+          switch (chan[i].panPos&0xe0) {
+            case 0: // center -> right
+              chan[i].panL=0xff-(chan[i].panPos<<2);
+              chan[i].panR=0xff;
+              break;
+            case 0x40: // right -> center
+              chan[i].panL=chan[i].panPos<<2;
+              chan[i].panR=0xff;
+              break;
+            case 0x80: // center -> left
+              chan[i].panL=0xff;
+              chan[i].panR=0xff-(chan[i].panPos<<2);
+              break;
+            case 0xc0: // left -> center
+              chan[i].panL=0xff;
+              chan[i].panR=chan[i].panPos<<2;
+              break;
+          }
+
+          dispatchCmd(DivCommand(DIV_CMD_PANNING,i,chan[i].panL,chan[i].panR));
+        }
+
+        // vibrato
         if (chan[i].vibratoDepth>0) {
           chan[i].vibratoPos+=chan[i].vibratoRate;
           while (chan[i].vibratoPos>=64) chan[i].vibratoPos-=64;
@@ -1632,6 +1719,8 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
           }
           dispatchCmd(DivCommand(DIV_CMD_PITCH,i,chan[i].pitch+(((chan[i].vibratoDepth*vibratoOut*chan[i].vibratoFine)>>4)/15)));
         }
+
+        // delayed legato
         if (chan[i].legatoDelay>0) {
           if (--chan[i].legatoDelay<1) {
             chan[i].note+=chan[i].legatoTarget;
@@ -1641,6 +1730,8 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
             chan[i].legatoTarget=0;
           }
         }
+
+        // portamento and pitch slides
         if (!song.noSlidesOnFirstTick || !firstTick) {
           if ((chan[i].keyOn || chan[i].keyOff) && chan[i].portaSpeed>0) {
             if (dispatchCmd(DivCommand(DIV_CMD_NOTE_PORTA,i,chan[i].portaSpeed*(song.linearPitch==2?song.pitchSlideSpeed:1),chan[i].portaNote))==2 && chan[i].portaStop && song.targetResetsSlides) {
@@ -1654,6 +1745,8 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
             }
           }
         }
+
+        // note cut
         if (chan[i].cut>0) {
           if (--chan[i].cut<1) {
             if (chan[i].cutType==2) {
@@ -1688,6 +1781,8 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
             }
           }
         }
+
+        // arpeggio
         if (chan[i].resetArp) {
           dispatchCmd(DivCommand(DIV_CMD_LEGATO,i,chan[i].note));
           dispatchCmd(DivCommand(DIV_CMD_HINT_LEGATO,i,chan[i].note));