From 41e59cee5f0e13e0f960b9d15e03e1e802ef5c35 Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Tue, 23 Apr 2024 19:55:17 -0500
Subject: [PATCH] Dave: implement sample offset

---
 src/engine/platform/dave.cpp | 18 +++++++++++++++---
 src/engine/platform/dave.h   |  5 +++--
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/engine/platform/dave.cpp b/src/engine/platform/dave.cpp
index 92e03c482..b84ebb61e 100644
--- a/src/engine/platform/dave.cpp
+++ b/src/engine/platform/dave.cpp
@@ -70,7 +70,7 @@ void DivPlatformDave::acquire(short** buf, size_t len) {
         chan[i].dacPeriod+=chan[i].dacRate;
         while (chan[i].dacPeriod>rate) {
           DivSample* s=parent->getSample(chan[i].dacSample);
-          if (s->samples<=0) {
+          if (s->samples<=0 || chan[i].dacPos>=s->samples) {
             chan[i].dacSample=-1;
             writeControl=true;
             chan[0].writeVol=true;
@@ -196,7 +196,11 @@ void DivPlatformDave::tick(bool sysTick) {
     if (chan[i].std.phaseReset.had && chan[i].std.phaseReset.val==1) {
       if (i>=4) {
         if (chan[i].active && chan[i].dacSample>=0 && chan[i].dacSample<parent->song.sampleLen) {
-          chan[i].dacPos=0;
+          if (chan[i].setPos) {
+            chan[i].setPos=false;
+          } else {
+            chan[i].dacPos=0;
+          }
           chan[i].dacPeriod=0;
           chan[i].keyOn=true;
         }
@@ -324,7 +328,11 @@ int DivPlatformDave::dispatch(DivCommand c) {
           chan[c.chan].freqChanged=true;
           chan[c.chan].note=c.value;
         }
-        chan[c.chan].dacPos=0;
+        if (chan[c.chan].setPos) {
+          chan[c.chan].setPos=false;
+        } else {
+          chan[c.chan].dacPos=0;
+        }
         chan[c.chan].dacPeriod=0;
         writeControl=true;
       } else {
@@ -459,6 +467,10 @@ int DivPlatformDave::dispatch(DivCommand c) {
       if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will && !NEW_ARP_STRAT) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
+    case DIV_CMD_SAMPLE_POS:
+      chan[c.chan].dacPos=c.value;
+      chan[c.chan].setPos=true;
+      break;
     case DIV_CMD_GET_VOLMAX:
       return 63;
       break;
diff --git a/src/engine/platform/dave.h b/src/engine/platform/dave.h
index 3b0183d3b..b232218be 100644
--- a/src/engine/platform/dave.h
+++ b/src/engine/platform/dave.h
@@ -33,7 +33,7 @@ class DivPlatformDave: public DivDispatch {
     unsigned char panL;
     unsigned char panR;
     unsigned char wave;
-    bool writeVol, highPass, ringMod, swapCounters, lowPass, resetPhase;
+    bool writeVol, highPass, ringMod, swapCounters, lowPass, resetPhase, setPos;
     Channel():
       SharedChannel<signed char>(63),
       dacPeriod(0),
@@ -50,7 +50,8 @@ class DivPlatformDave: public DivDispatch {
       ringMod(false),
       swapCounters(false),
       lowPass(false),
-      resetPhase(false) {}
+      resetPhase(false),
+      setPos(false) {}
   };
   Channel chan[6];
   DivDispatchOscBuffer* oscBuf[6];