From b48a2368bed445e11da1265600bf17f71a8456d2 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Fri, 15 Apr 2022 22:22:47 -0500
Subject: [PATCH] more low-latency mode work

playSub() runs at normal tick rate
---
 src/engine/engine.cpp   |  1 +
 src/engine/playback.cpp | 10 +++--
 src/gui/gui.cpp         | 91 +++++++++++++++++++----------------------
 src/gui/gui.h           |  1 +
 4 files changed, 51 insertions(+), 52 deletions(-)

diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 6257ff537..bb53fd2a3 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -853,6 +853,7 @@ void DivEngine::playSub(bool preserveDrift, int goalRow) {
   }
   if (!preserveDrift) {
     ticks=1;
+    subticks=1;
   }
   skipping=false;
   cmdStream.clear();
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 2b22abd24..bd8b2b8af 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1476,15 +1476,17 @@ bool DivEngine::nextTick(bool noAccum) {
   bool ret=false;
   if (divider<10) divider=10;
 
-  if (lowLatency) {
+  if (lowLatency && !skipping) {
     tickMult=1000/divider;
     if (tickMult<1) tickMult=1;
+  } else {
+    tickMult=1;
   }
   
   cycles=got.rate*pow(2,MASTER_CLOCK_PREC)/(divider*tickMult);
-  clockDrift+=fmod(got.rate*pow(2,MASTER_CLOCK_PREC),(double)divider);
-  if (clockDrift>=divider) {
-    clockDrift-=divider;
+  clockDrift+=fmod(got.rate*pow(2,MASTER_CLOCK_PREC),(double)(divider*tickMult));
+  if (clockDrift>=(divider*tickMult)) {
+    clockDrift-=(divider*tickMult);
     cycles++;
   }
 
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index ba83b8654..4fcd60ddd 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -1078,9 +1078,6 @@ void FurnaceGUI::keyDown(SDL_Event& ev) {
             if (edit) {
               noteInput(num,key);
             }
-            if (key!=100 && key!=101 && key!=102) {
-              previewNote(cursor.xCoarse,num);
-            }
           } catch (std::out_of_range& e) {
           }
         } else if (edit) { // value
@@ -1184,22 +1181,8 @@ void FurnaceGUI::keyDown(SDL_Event& ev) {
   }
 
   // PER-WINDOW PREVIEW KEYS
+  // TODO: move this to new event handler
   switch (curWindow) {
-    case GUI_WINDOW_INS_EDIT:
-    case GUI_WINDOW_INS_LIST:
-    case GUI_WINDOW_EDIT_CONTROLS:
-    case GUI_WINDOW_SONG_INFO:
-      if (!ev.key.repeat) {
-        try {
-          int key=noteKeys.at(ev.key.keysym.scancode);
-          int num=12*curOctave+key;
-          if (key!=100 && key!=101 && key!=102) {
-            previewNote(cursor.xCoarse,num);
-          }
-        } catch (std::out_of_range& e) {
-        }
-      }
-      break;
     case GUI_WINDOW_SAMPLE_EDIT:
     case GUI_WINDOW_SAMPLE_LIST:
       if (!ev.key.repeat) {
@@ -1238,19 +1221,7 @@ void FurnaceGUI::keyDown(SDL_Event& ev) {
 }
 
 void FurnaceGUI::keyUp(SDL_Event& ev) {
-  stopPreviewNote(ev.key.keysym.scancode,true);
-  if (wavePreviewOn) {
-    if (ev.key.keysym.scancode==wavePreviewKey) {
-      wavePreviewOn=false;
-      e->stopWavePreview();
-    }
-  }
-  if (samplePreviewOn) {
-    if (ev.key.keysym.scancode==samplePreviewKey) {
-      samplePreviewOn=false;
-      e->stopSamplePreview();
-    }
-  }
+  // nothing for now
 }
 
 bool dirExists(String what) {
@@ -2021,7 +1992,47 @@ void FurnaceGUI::editOptions(bool topMenu) {
   }
 }
 
+int _processEvent(void* instance, SDL_Event* event) {
+  return ((FurnaceGUI*)instance)->processEvent(event);
+}
+
+int FurnaceGUI::processEvent(SDL_Event* ev) {
+  if (ev->type==SDL_KEYDOWN) {
+    if (!ev->key.repeat) {
+      try {
+        int key=noteKeys.at(ev->key.keysym.scancode);
+        int num=12*curOctave+key;
+
+        if (num<-60) num=-60; // C-(-5)
+        if (num>119) num=119; // B-9
+
+        if (key!=100 && key!=101 && key!=102) {
+          previewNote(cursor.xCoarse,num);
+        }
+      } catch (std::out_of_range& e) {
+      }
+    }
+  } else if (ev->type==SDL_KEYUP) {
+    stopPreviewNote(ev->key.keysym.scancode,true);
+    if (wavePreviewOn) {
+      if (ev->key.keysym.scancode==wavePreviewKey) {
+        wavePreviewOn=false;
+        e->stopWavePreview();
+      }
+    }
+    if (samplePreviewOn) {
+      if (ev->key.keysym.scancode==samplePreviewKey) {
+        samplePreviewOn=false;
+        e->stopSamplePreview();
+      }
+    }
+  }
+  return 1;
+}
+
 bool FurnaceGUI::loop() {
+  SDL_SetEventFilter(_processEvent,this);
+
   while (!quit) {
     SDL_Event ev;
     while (SDL_PollEvent(&ev)) {
@@ -2131,23 +2142,7 @@ bool FurnaceGUI::loop() {
           }
           break;
         case SDL_KEYUP:
-          if (!ImGui::GetIO().WantCaptureKeyboard) {
-            keyUp(ev);
-          } else {
-            stopPreviewNote(ev.key.keysym.scancode,true);
-            if (wavePreviewOn) {
-              if (ev.key.keysym.scancode==wavePreviewKey) {
-                wavePreviewOn=false;
-                e->stopWavePreview();
-              }
-            }
-            if (samplePreviewOn) {
-              if (ev.key.keysym.scancode==samplePreviewKey) {
-                samplePreviewOn=false;
-                e->stopSamplePreview();
-              }
-            }
-          }
+          // for now
           break;
         case SDL_DROPFILE:
           if (ev.drop.file!=NULL) {
diff --git a/src/gui/gui.h b/src/gui/gui.h
index 67d084a47..5983057b5 100644
--- a/src/gui/gui.h
+++ b/src/gui/gui.h
@@ -1215,6 +1215,7 @@ class FurnaceGUI {
     void addScroll(int amount);
     void setFileName(String name);
     void runBackupThread();
+    int processEvent(SDL_Event* ev);
     bool loop();
     bool finish();
     bool init();