From 45460df96d24c87fea90e58fe3d48a235c23e9f1 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Fri, 15 Apr 2022 14:38:25 -0500
Subject: [PATCH] improve low-latency mode strategy

---
 src/engine/engine.cpp   |  2 ++
 src/engine/macroInt.cpp | 25 ++++++++++++++++---------
 src/engine/macroInt.h   | 11 ++++++-----
 src/engine/playback.cpp |  2 +-
 4 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 81d7947a7..6257ff537 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -2237,6 +2237,8 @@ bool DivEngine::initAudioBackend() {
   if (metroVol<0.0f) metroVol=0.0f;
   if (metroVol>2.0f) metroVol=2.0f;
 
+  if (lowLatency) logI("using low latency mode.");
+
   switch (audioEngine) {
     case DIV_AUDIO_JACK:
 #ifndef HAVE_JACK
diff --git a/src/engine/macroInt.cpp b/src/engine/macroInt.cpp
index ae6caf5df..00fee080e 100644
--- a/src/engine/macroInt.cpp
+++ b/src/engine/macroInt.cpp
@@ -21,14 +21,19 @@
 #include "instrument.h"
 #include "engine.h"
 
-void DivMacroStruct::doMacro(DivInstrumentMacro& source, bool released) {
+void DivMacroStruct::doMacro(DivInstrumentMacro& source, bool released, bool tick) {
+  if (!tick) {
+    had=false;
+    return;
+  }
   if (finished) {
     finished=false;
   }
-  if (had!=has) {
+  if (actualHad!=has) {
     finished=true;
   }
-  had=has;
+  actualHad=has;
+  had=actualHad;
   if (has) {
     val=source.val[pos++];
     if (source.rel>=0 && pos>source.rel && !released) {
@@ -52,17 +57,18 @@ void DivMacroInt::next() {
   if (ins==NULL) return;
   // run macros
   // TODO: potentially get rid of list to avoid allocations
-  if (--subTick<=0) {
+  subTick--;
+  for (size_t i=0; i<macroListLen; i++) {
+    if (macroList[i]!=NULL && macroSource[i]!=NULL) {
+      macroList[i]->doMacro(*macroSource[i],released,subTick==0);
+    }
+  }
+  if (subTick<=0) {
     if (e==NULL) {
       subTick=1;
     } else {
       subTick=e->tickMult;
     }
-    for (size_t i=0; i<macroListLen; i++) {
-      if (macroList[i]!=NULL && macroSource[i]!=NULL) {
-        macroList[i]->doMacro(*macroSource[i],released);
-      }
-    }
   }
 }
 
@@ -85,6 +91,7 @@ void DivMacroInt::init(DivInstrument* which) {
     if (macroList[i]!=NULL) macroList[i]->init();
   }
   macroListLen=0;
+  subTick=1;
 
   released=false;
 
diff --git a/src/engine/macroInt.h b/src/engine/macroInt.h
index 886ecbe23..f1cd29a7e 100644
--- a/src/engine/macroInt.h
+++ b/src/engine/macroInt.h
@@ -27,17 +27,17 @@ class DivEngine;
 struct DivMacroStruct {
   int pos;
   int val;
-  bool has, had, finished, will;
+  bool has, had, actualHad, finished, will;
   unsigned int mode;
-  void doMacro(DivInstrumentMacro& source, bool released);
+  void doMacro(DivInstrumentMacro& source, bool released, bool tick);
   void init() {
     pos=mode=0;
-    has=had=will=false;
+    has=had=actualHad=will=false;
     // TODO: test whether this breaks anything?
     val=0;
   }
   void prepare(DivInstrumentMacro& source) {
-    has=had=will=true;
+    has=had=actualHad=will=true;
     mode=source.mode;
   }
   DivMacroStruct():
@@ -45,6 +45,7 @@ struct DivMacroStruct {
     val(0),
     has(false),
     had(false),
+    actualHad(false),
     finished(false),
     will(false),
     mode(0) {}
@@ -128,7 +129,7 @@ class DivMacroInt {
       e(NULL),
       ins(NULL),
       macroListLen(0),
-      subTick(0),
+      subTick(1),
       released(false),
       vol(),
       arp(),
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index ea2213305..fe42c73af 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1654,7 +1654,7 @@ bool DivEngine::nextTick(bool noAccum) {
       }
     }
 
-    if (consoleMode) fprintf(stderr,"\x1b[2K> %d:%.2d:%.2d.%.2d  %.2x/%.2x:%.3d/%.3d  %4dcmd/s\x1b[G",totalSeconds/3600,(totalSeconds/60)%60,totalSeconds%60,totalTicks/10000,curOrder,song.ordersLen,curRow,song.patLen,cmdsPerSecond);
+    if (consoleMode && subticks<=1) fprintf(stderr,"\x1b[2K> %d:%.2d:%.2d.%.2d  %.2x/%.2x:%.3d/%.3d  %4dcmd/s\x1b[G",totalSeconds/3600,(totalSeconds/60)%60,totalSeconds%60,totalTicks/10000,curOrder,song.ordersLen,curRow,song.patLen,cmdsPerSecond);
   }
 
   if (haltOn==DIV_HALT_TICK) halted=true;