GUI: introduce power-saving mode

src/gui/gui.cpp

@@ -2038,7 +2038,15 @@ bool FurnaceGUI::loop() {
 
   while (!quit) {
     SDL_Event ev;
+    if (e->isPlaying()) {
+      WAKE_UP;
+    }
+    if (--drawHalt<=0) {
+      drawHalt=0;
+      if (settings.powerSave) SDL_WaitEventTimeout(NULL,500);
+    }
     while (SDL_PollEvent(&ev)) {
+      WAKE_UP;
       ImGui_ImplSDL2_ProcessEvent(&ev);
       switch (ev.type) {
         case SDL_MOUSEMOTION: {
@@ -3425,6 +3433,7 @@ FurnaceGUI::FurnaceGUI():
   wantCaptureKeyboard(false),
   displayNew(false),
   vgmExportVersion(0x171),
+  drawHalt(10),
   curFileDialog(GUI_FILE_OPEN),
   warnAction(GUI_WARN_OPEN),
   postWarnAction(GUI_WARN_GENERIC),

src/gui/gui.h

@@ -41,6 +41,7 @@
 #define unimportant(x) if (x) {handleUnimportant}
 
 #define MARK_MODIFIED modified=true;
+#define WAKE_UP drawHalt=16;
 
 #define TOGGLE_COLOR(x) ((x)?uiColors[GUI_COLOR_TOGGLE_ON]:uiColors[GUI_COLOR_TOGGLE_OFF])
 
@@ -715,6 +716,7 @@ class FurnaceGUI {
   bool displayNew;
   bool willExport[32];
   int vgmExportVersion;
+  int drawHalt;
 
   FurnaceGUIFileDialogs curFileDialog;
   FurnaceGUIWarnings warnAction;
@@ -820,6 +822,7 @@ class FurnaceGUI {
     int cursorMoveNoScroll;
     int lowLatency;
     int notePreviewBehavior;
+    int powerSave;
     unsigned int maxUndoSteps;
     String mainFontPath;
     String patFontPath;
@@ -893,6 +896,7 @@ class FurnaceGUI {
       cursorMoveNoScroll(0),
       lowLatency(0),
       notePreviewBehavior(1),
+      powerSave(1),
       maxUndoSteps(100),
       mainFontPath(""),
       patFontPath(""),

src/gui/osc.cpp

@@ -49,12 +49,19 @@ void FurnaceGUI::readOsc() {
   for (int i=0; i<512; i++) {
     int pos=(readPos+(i*total/512))&0x7fff;
     oscValues[i]=(e->oscBuf[0][pos]+e->oscBuf[1][pos])*0.5f;
+    if (oscValues[i]>0.001f || oscValues[i]<-0.001f) {
+      WAKE_UP;
+    }
   }
 
   float peakDecay=0.05f*60.0f*ImGui::GetIO().DeltaTime;
   for (int i=0; i<2; i++) {
     peak[i]*=1.0-peakDecay;
-    if (peak[i]<0.0001) peak[i]=0.0;
+    if (peak[i]<0.0001) {
+      peak[i]=0.0;
+    } else {
+      WAKE_UP;
+    }
     float newPeak=peak[i];
     for (int j=0; j<total; j++) {
       int pos=(readPos+j)&0x7fff;

src/gui/pattern.cpp

@@ -890,6 +890,7 @@ void FurnaceGUI::drawPattern() {
 
       // particle simulation
       ImDrawList* fdl=ImGui::GetForegroundDrawList();
+      if (!particles.empty()) WAKE_UP;
       for (size_t i=0; i<particles.size(); i++) {
         Particle& part=particles[i];
         if (part.update(frameTime)) {

src/gui/settings.cpp

@@ -31,6 +31,13 @@
 
 #define DEFAULT_NOTE_KEYS "5:7;6:4;7:3;8:16;10:6;11:8;12:24;13:10;16:11;17:9;18:26;19:28;20:12;21:17;22:1;23:19;24:23;25:5;26:14;27:2;28:21;29:0;30:100;31:13;32:15;34:18;35:20;36:22;38:25;39:27;43:100;46:101;47:29;48:31;53:102;"
 
+#if defined(_WIN32) || defined(__APPLE__)
+#define POWER_SAVE_DEFAULT 1
+#else
+// currently off on Linux/other due to Mesa catch-up behavior.
+#define POWER_SAVE_DEFAULT 0
+#endif
+
 const char* mainFonts[]={
   "IBM Plex Sans",
   "Liberation Sans",
@@ -301,7 +308,15 @@ void FurnaceGUI::drawSettings() {
           settings.sysFileDialog=sysFileDialogB;
         }
 
-        ImGui::Text("Note preview behavioe:");
+        bool powerSaveB=settings.powerSave;
+        if (ImGui::Checkbox("Power-saving mode",&powerSaveB)) {
+          settings.powerSave=powerSaveB;
+        }
+        if (ImGui::IsItemHovered()) {
+          ImGui::SetTooltip("saves power by lowering the frame rate to 2fps when idle.\nmay cause issues under Mesa drivers!");
+        }
+
+        ImGui::Text("Note preview behavior:");
         if (ImGui::RadioButton("Never##npb0",settings.notePreviewBehavior==0)) {
           settings.notePreviewBehavior=0;
         }
@@ -1624,6 +1639,7 @@ void FurnaceGUI::syncSettings() {
   settings.cursorMoveNoScroll=e->getConfInt("cursorMoveNoScroll",0);
   settings.lowLatency=e->getConfInt("lowLatency",0);
   settings.notePreviewBehavior=e->getConfInt("notePreviewBehavior",1);
+  settings.powerSave=e->getConfInt("powerSave",POWER_SAVE_DEFAULT);
 
   clampSetting(settings.mainFontSize,2,96);
   clampSetting(settings.patFontSize,2,96);
@@ -1686,6 +1702,7 @@ void FurnaceGUI::syncSettings() {
   clampSetting(settings.cursorMoveNoScroll,0,1);
   clampSetting(settings.lowLatency,0,1);
   clampSetting(settings.notePreviewBehavior,0,3);
+  clampSetting(settings.powerSave,0,1);
 
   // keybinds
   for (int i=0; i<GUI_ACTION_MAX; i++) {
@@ -1775,6 +1792,7 @@ void FurnaceGUI::commitSettings() {
   e->setConf("cursorMoveNoScroll",settings.cursorMoveNoScroll);
   e->setConf("lowLatency",settings.lowLatency);
   e->setConf("notePreviewBehavior",settings.notePreviewBehavior);
+  e->setConf("powerSave",settings.powerSave);
 
   // colors
   for (int i=0; i<GUI_COLOR_MAX; i++) {