From 530a9bafc7fefd93849a8dd44f9478432900fede Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Tue, 4 Jan 2022 00:02:41 -0500
Subject: [PATCH] add a metronome

---
 src/engine/engine.cpp   |  9 +++++++++
 src/engine/engine.h     | 17 +++++++++++++++++
 src/engine/playback.cpp | 35 +++++++++++++++++++++++++++++++++++
 src/gui/gui.cpp         |  5 +++++
 4 files changed, 66 insertions(+)

diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index d336dac54..f507ec64f 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -2044,6 +2044,15 @@ void DivEngine::setView(DivStatusView which) {
   view=which;
 }
 
+bool DivEngine::getMetronome() {
+  return metronome;
+}
+
+void DivEngine::setMetronome(bool enable) {
+  metronome=enable;
+  metroAmp=0;
+}
+
 void DivEngine::setConsoleMode(bool enable) {
   consoleMode=enable;
 }
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 29a880afd..fede7dde6 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -106,6 +106,7 @@ class DivEngine {
   bool consoleMode;
   bool extValuePresent;
   bool repeatPattern;
+  bool metronome;
   int ticks, cycles, curRow, curOrder, remainingLoops, nextSpeed, clockDrift;
   int changeOrd, changePos, totalTicks, totalCmds, lastCmds, cmdsPerSecond, globalPitch;
   unsigned char extValue;
@@ -136,6 +137,10 @@ class DivEngine {
   int temp[3], prevSample[3];
   short* bbIn[3];
   short* bbOut[3];
+  unsigned char* metroTick;
+  size_t metroTickLen;
+  int metroPeriod, metroPos;
+  float metroAmp;
 
   size_t totalProcessed;
 
@@ -356,6 +361,12 @@ class DivEngine {
 
     // set the console mode.
     void setConsoleMode(bool enable);
+    
+    // get metronome
+    bool getMetronome();
+
+    // set metronome
+    void setMetronome(bool enable);
 
     // public render samples
     void renderSamplesP();
@@ -390,6 +401,7 @@ class DivEngine {
       consoleMode(false),
       extValuePresent(false),
       repeatPattern(false),
+      metronome(false),
       ticks(0),
       cycles(0),
       curRow(0),
@@ -411,6 +423,11 @@ class DivEngine {
       bbInLen(0),
       temp{0,0},
       prevSample{0,0},
+      metroTick(NULL),
+      metroTickLen(0),
+      metroPeriod(0),
+      metroPos(0),
+      metroAmp(0.0f),
       totalProcessed(0),
       jediTable(NULL),
       adpcmMem(NULL) {}
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index eb1cd41f7..d000913ee 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -882,6 +882,14 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
     bbInLen=runtotal+256;
   }
 
+  if (metroTickLen<size) {
+    if (metroTick!=NULL) delete[] metroTick;
+    metroTick=new unsigned char[size];
+    metroTickLen=size;
+  }
+
+  memset(metroTick,0,size);
+
   size_t runLeft=runtotal;
   size_t runPos=0;
   totalProcessed=0;
@@ -895,6 +903,14 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
         runLeft-=cycles;
         dispatch->acquire(bbIn[0],bbIn[1],runPos,cycles);
         runPos+=cycles;
+        unsigned int realPos=(runPos*size)/runtotal;
+        if (realPos>=size) realPos=size-1;
+        if (song.hilightA>0) {
+          if ((curRow%song.hilightA)==0 && ticks==1) metroTick[realPos]=1;
+        }
+        if (song.hilightB>0) {
+          if ((curRow%song.hilightB)==0 && ticks==1) metroTick[realPos]=2;
+        }
         if (nextTick()) {
           if (remainingLoops>0) {
             remainingLoops--;
@@ -947,5 +963,24 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
       out[1][i]+=(float)bbOut[0][i]/16384.0;
     }
   }
+
+  if (metronome) for (size_t i=0; i<size; i++) {
+    if (metroTick[i]) {
+      if (metroTick[i]==2) {
+        metroPeriod=30;
+      } else {
+        metroPeriod=40;
+      }
+      metroPos=metroPeriod;
+      metroAmp=0.5f;
+    }
+    out[0][i]+=(metroPos>(metroPeriod>>1))*metroAmp;
+    out[1][i]+=(metroPos>(metroPeriod>>1))*metroAmp;
+    metroAmp-=0.0002f;
+    if (metroAmp<0.0f) metroAmp=0.0f;
+    if (--metroPos<=0) {
+      metroPos=metroPeriod;
+    }
+  }
   isBusy.unlock();
 }
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index 829058811..805927b02 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -273,6 +273,11 @@ void FurnaceGUI::drawEditControls() {
     }
     ImGui::SameLine();
     ImGui::Checkbox("Edit",&edit);
+    ImGui::SameLine();
+    bool metro=e->getMetronome();
+    if (ImGui::Checkbox("Metronome",&metro)) {
+      e->setMetronome(metro);
+    }
 
     ImGui::Text("Follow");
     ImGui::SameLine();