implement volMacroLinger compatibility flag

issue #425

TODO.md

@@ -4,8 +4,9 @@
   - CSM
 - MSM6258 pitch and clock select
 - the last three compat flags
+  - newVolumeScaling
+  - brokenOutVol
 - collapse/expand pattern and song
-- add OPL drum instrument type
 - Game Boy envelope macro/sequence
 - rewrite the system name detection function anyway
 - volume commands should work on Game Boy

src/engine/macroInt.cpp

@@ -21,6 +21,12 @@
 #include "instrument.h"
 #include "engine.h"
 
+void DivMacroStruct::prepare(DivInstrumentMacro& source, DivEngine* e) {
+  has=had=actualHad=will=true;
+  mode=source.mode;
+  linger=(source.name=="vol" && e->song.volMacroLinger);
+}
+
 void DivMacroStruct::doMacro(DivInstrumentMacro& source, bool released, bool tick) {
   if (!tick) {
     had=false;
@@ -46,6 +52,8 @@ void DivMacroStruct::doMacro(DivInstrumentMacro& source, bool released, bool tic
     if (pos>=source.len) {
       if (source.loop<source.len && source.loop>=0 && (source.loop>=source.rel || source.rel>=source.len)) {
         pos=source.loop;
+      } else if (linger) {
+        pos--;
       } else {
         has=false;
       }
@@ -228,7 +236,7 @@ void DivMacroInt::init(DivInstrument* which) {
   }
 
   for (size_t i=0; i<macroListLen; i++) {
-    macroList[i]->prepare(*macroSource[i]);
+    macroList[i]->prepare(*macroSource[i],e);
   }
 }
 

src/engine/macroInt.h

@@ -27,19 +27,17 @@ class DivEngine;
 struct DivMacroStruct {
   int pos;
   int val;
-  bool has, had, actualHad, finished, will;
+  bool has, had, actualHad, finished, will, linger;
   unsigned int mode;
   void doMacro(DivInstrumentMacro& source, bool released, bool tick);
   void init() {
     pos=mode=0;
     has=had=actualHad=will=false;
+    linger=false;
     // TODO: test whether this breaks anything?
     val=0;
   }
-  void prepare(DivInstrumentMacro& source) {
-    has=had=actualHad=will=true;
-    mode=source.mode;
-  }
+  void prepare(DivInstrumentMacro& source, DivEngine* e);
   DivMacroStruct():
     pos(0),
     val(0),
@@ -48,6 +46,7 @@ struct DivMacroStruct {
     actualHad(false),
     finished(false),
     will(false),
+    linger(false),
     mode(0) {}
 };
 

src/gui/compatFlags.cpp

@@ -123,6 +123,18 @@ void FurnaceGUI::drawCompatFlags() {
     if (ImGui::IsItemHovered()) {
       ImGui::SetTooltip("when enabled, the pitch macro of an instrument is in linear space.");
     }
+    ImGui::Checkbox("Proper volume scaling strategy",&e->song.newVolumeScaling);
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("when disabled:\n- log scaling: multiply\n- linear scaling: subtract\nwhen enabled:\n- log scaling: subtract\n- linear scaling: multiply");
+    }
+    ImGui::Checkbox("Persist volume macro after it finishes",&e->song.volMacroLinger);
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("when disabled, a value in the volume column that happens after the volume macro is done will disregard the macro.");
+    }
+    ImGui::Checkbox("Broken output volume on instrument change",&e->song.brokenOutVol);
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("if enabled, no checks for the presence of a volume macro will be made.\nthis will cause the last macro value to linger unless a value in the volume column is present.");
+    }
 
     ImGui::Text("Pitch linearity:");
     if (ImGui::RadioButton("None",e->song.linearPitch==0)) {