From 21994a7eee091069cbc2ebdebc04d5dfe2775cbb Mon Sep 17 00:00:00 2001
From: Dalia <dc@dalia.cc>
Date: Sun, 17 Nov 2024 12:45:39 -0700
Subject: [PATCH] per-channel arpeggio speeds

E0xx works on a per-channel basis for new songs. old behaviour can be
toggled with a compatibility flag
---
 src/engine/cmdStream.cpp   |  9 +++++++--
 src/engine/cmdStream.h     |  3 ++-
 src/engine/engine.h        |  3 ++-
 src/engine/fileOps/dmf.cpp |  1 +
 src/engine/fileOps/fur.cpp |  3 +++
 src/engine/playback.cpp    | 10 +++++++---
 src/engine/song.h          |  4 +++-
 src/gui/compatFlags.cpp    |  4 ++++
 8 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/src/engine/cmdStream.cpp b/src/engine/cmdStream.cpp
index f1b267869a..9508994c16 100644
--- a/src/engine/cmdStream.cpp
+++ b/src/engine/cmdStream.cpp
@@ -352,7 +352,11 @@ bool DivCSPlayer::tick() {
             chan[i].arp=(((unsigned char)arg0)<<4)|(arg1&15);
             break;
           case DIV_CMD_HINT_ARP_TIME:
-            arpSpeed=arg0;
+            if (e->song.arpSpeedGlobal) {
+              arpSpeed=arg0;
+            } else {
+              chan[i].arpLen=arg0;
+            }
             break;
           default: // dispatch it
             e->dispatchCmd(DivCommand((DivDispatchCmds)command,i,arg0,arg1));
@@ -422,7 +426,7 @@ bool DivCSPlayer::tick() {
         }
         chan[i].arpStage++;
         if (chan[i].arpStage>=3) chan[i].arpStage=0;
-        chan[i].arpTicks=arpSpeed;
+        chan[i].arpTicks=(e->song.arpSpeedGlobal)?arpSpeed:chan[i].arpLen;
       }
       chan[i].arpTicks--;
     }
@@ -460,6 +464,7 @@ bool DivCSPlayer::init() {
   for (int i=0; i<e->getTotalChannelCount(); i++) {
     chan[i].volMax=(e->getDispatch(e->dispatchOfChan[i])->dispatch(DivCommand(DIV_CMD_GET_VOLMAX,e->dispatchChanOfChan[i]))<<8)|0xff;
     chan[i].volume=chan[i].volMax;
+    chan[i].arpLen=1;
   }
 
   for (int i=0; i<64; i++) {
diff --git a/src/engine/cmdStream.h b/src/engine/cmdStream.h
index 2d8e6e97ef..ad645b5f34 100644
--- a/src/engine/cmdStream.h
+++ b/src/engine/cmdStream.h
@@ -37,7 +37,7 @@ struct DivCSChannelState {
   int volume, volMax, volSpeed, volSpeedTarget;
   int vibratoDepth, vibratoRate, vibratoPos;
   int portaTarget, portaSpeed;
-  unsigned char arp, arpStage, arpTicks;
+  unsigned char arp, arpStage, arpTicks, arpLen;
 
   unsigned int callStack[8];
   unsigned char callStackPos;
@@ -65,6 +65,7 @@ struct DivCSChannelState {
     arp(0),
     arpStage(0),
     arpTicks(0),
+    arpLen(1),
     callStackPos(0),
     tracePos(0) {
     for (int i=0; i<DIV_MAX_CSTRACE; i++) {
diff --git a/src/engine/engine.h b/src/engine/engine.h
index e6ffecb970..c6d603b3bb 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -139,7 +139,7 @@ struct DivChannelState {
   int tremoloDepth, tremoloRate, tremoloPos;
   int panDepth, panRate, panPos, panSpeed;
   int sampleOff;
-  unsigned char arp, arpStage, arpTicks, panL, panR, panRL, panRR, lastVibrato, lastPorta, cutType;
+  unsigned char arp, arpStage, arpTicks, arpLen, panL, panR, panRL, panRR, lastVibrato, lastPorta, cutType;
   bool doNote, legato, portaStop, keyOn, keyOff, nowYouCanStop, stopOnOff, releasing;
   bool arpYield, delayLocked, inPorta, scheduledSlideReset, shorthandPorta, wasShorthandPorta, noteOnInhibit, resetArp, sampleOffSet;
   bool wentThroughNote, goneThroughNote;
@@ -185,6 +185,7 @@ struct DivChannelState {
     arp(0),
     arpStage(-1),
     arpTicks(1),
+    arpLen(1),
     panL(255),
     panR(255),
     panRL(0),
diff --git a/src/engine/fileOps/dmf.cpp b/src/engine/fileOps/dmf.cpp
index d226a54e83..e3fd1cc934 100644
--- a/src/engine/fileOps/dmf.cpp
+++ b/src/engine/fileOps/dmf.cpp
@@ -216,6 +216,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
       ds.delayBehavior=0;
       ds.jumpTreatment=2;
       ds.oldAlwaysSetVolume=true;
+      ds.arpSpeedGlobal=true;
 
       // 1.1 compat flags
       if (ds.version>24) {
diff --git a/src/engine/fileOps/fur.cpp b/src/engine/fileOps/fur.cpp
index bcee8e9ba9..bedbb6fffd 100644
--- a/src/engine/fileOps/fur.cpp
+++ b/src/engine/fileOps/fur.cpp
@@ -864,6 +864,9 @@ bool DivEngine::loadFur(unsigned char* file, size_t len, int variantID) {
     if (ds.version<200) {
       ds.oldSampleOffset=true;
     }
+    if (ds.version<224) {
+      ds.arpSpeedGlobal=true;
+    }
     ds.isDMF=false;
 
     reader.readS(); // reserved
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 0c8f4fdbf4..181c13b769 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1020,8 +1020,12 @@ void DivEngine::processRow(int i, bool afterDelay) {
         break;
       case 0xe0: // arp speed
         if (effectVal>0) {
-          curSubSong->arpLen=effectVal;
-          dispatchCmd(DivCommand(DIV_CMD_HINT_ARP_TIME,i,curSubSong->arpLen));
+          if (song.arpSpeedGlobal) {
+            curSubSong->arpLen=effectVal;
+          } else {
+            chan[i].arpLen=effectVal;
+          }
+          dispatchCmd(DivCommand(DIV_CMD_HINT_ARP_TIME,i,effectVal));
         }
         break;
       case 0xe1: // portamento up
@@ -1933,7 +1937,7 @@ bool DivEngine::nextTick(bool noAccum, bool inhibitLowLat) {
         }
         if (chan[i].arp!=0 && !chan[i].arpYield && chan[i].portaSpeed<1) {
           if (--chan[i].arpTicks<1) {
-            chan[i].arpTicks=curSubSong->arpLen;
+            chan[i].arpTicks=song.arpSpeedGlobal?curSubSong->arpLen:chan[i].arpLen;
             chan[i].arpStage++;
             if (chan[i].arpStage>2) chan[i].arpStage=0;
             switch (chan[i].arpStage) {
diff --git a/src/engine/song.h b/src/engine/song.h
index ef745d0cd9..c91e739eb1 100644
--- a/src/engine/song.h
+++ b/src/engine/song.h
@@ -349,6 +349,7 @@ struct DivSong {
   bool ceilVolumeScaling;
   bool oldAlwaysSetVolume;
   bool oldSampleOffset;
+  bool arpSpeedGlobal;
 
   std::vector<DivInstrument*> ins;
   std::vector<DivWavetable*> wave;
@@ -478,7 +479,8 @@ struct DivSong {
     resetArpPhaseOnNewNote(false),
     ceilVolumeScaling(false),
     oldAlwaysSetVolume(false),
-    oldSampleOffset(false) {
+    oldSampleOffset(false),
+    arpSpeedGlobal(false) {
     for (int i=0; i<DIV_MAX_CHIPS; i++) {
       system[i]=DIV_SYSTEM_NULL;
       systemVol[i]=1.0;
diff --git a/src/gui/compatFlags.cpp b/src/gui/compatFlags.cpp
index 48d36fc913..4d73b4f0f9 100644
--- a/src/gui/compatFlags.cpp
+++ b/src/gui/compatFlags.cpp
@@ -200,6 +200,10 @@ void FurnaceGUI::drawCompatFlags() {
         if (ImGui::IsItemHovered()) {
           ImGui::SetTooltip(_("behavior changed in 0.6.3"));
         }
+        ImGui::Checkbox(_("Global arpeggio speed (E0xx)"),&e->song.arpSpeedGlobal);
+        if (ImGui::IsItemHovered()) {
+          ImGui::SetTooltip(_("when enabled, E0xx will affect all channels simultaneously."));
+        }
         ImGui::EndTabItem();
       }
       if (ImGui::BeginTabItem(_(".mod import"))) {