configurable music gap

Author: mkalkbrenner

examples/ppuc-pinmame.ini

@@ -29,6 +29,9 @@ SpeechFile =
 # Optional comma-separated MP3 playlist for gameplay background music.
 MusicFiles =
 
+# Optional gap between background music tracks in milliseconds.
+MusicGapMs = 2000
+
 # Optional translite image for in-game mode.
 Translite =
 

src/AudioOutput.cpp

@@ -16,7 +16,6 @@ constexpr float kMusicBaseGain = 0.28f;
 constexpr float kMusicDuckGain = 0.08f;
 constexpr float kMusicAttackPerSample = 0.00012f;
 constexpr float kMusicReleasePerSample = 0.00003f;
-
 static int16_t ClampMixedSample(int value)
 {
   if (value > std::numeric_limits<int16_t>::max())
@@ -147,6 +146,10 @@ bool AudioOutput::LoadMusicFilesCsv(const char* csv, std::string* errorMessage)
   musicTrackIndex_ = 0;
   musicGain_ = 0.0f;
   musicEnabled_ = false;
+#if defined(PPUC_HAS_SDL3_MIXER)
+  musicTrackStartPending_ = false;
+  musicTrackStartTickMs_ = 0;
+#endif
 
 #if defined(PPUC_HAS_SDL3_MIXER)
   return ReloadMusicTracksLocked(errorMessage);
@@ -162,6 +165,7 @@ bool AudioOutput::LoadMusicFilesCsv(const char* csv, std::string* errorMessage)
 void AudioOutput::SetMusicEnabled(bool enabled)
 {
   std::lock_guard<std::mutex> lock(mutex_);
+  const bool wasEnabled = musicEnabled_;
   musicEnabled_ = enabled;
 
 #if defined(PPUC_HAS_SDL3_MIXER)
@@ -176,7 +180,13 @@ void AudioOutput::SetMusicEnabled(bool enabled)
     return;
   }
 
-  if (MIX_TrackPaused(musicTrack_))
+  if (!wasEnabled)
+  {
+    musicTrackStartPending_ = false;
+    musicTrackStartTickMs_ = 0;
+    StartCurrentMusicTrackLocked();
+  }
+  else if (MIX_TrackPaused(musicTrack_))
   {
     MIX_ResumeTrack(musicTrack_);
   }
@@ -187,6 +197,16 @@ void AudioOutput::SetMusicEnabled(bool enabled)
 #endif
 }
 
+void AudioOutput::SetMusicTrackGapMs(Uint64 gapMs)
+{
+  std::lock_guard<std::mutex> lock(mutex_);
+#if defined(PPUC_HAS_SDL3_MIXER)
+  musicTrackGapMs_ = gapMs;
+#else
+  (void)gapMs;
+#endif
+}
+
 void AudioOutput::QueueGameFrames(const int16_t* samples, size_t frameCount)
 {
   if (samples == nullptr || frameCount == 0)
@@ -379,6 +399,22 @@ void AudioOutput::MixMusicLocked(int16_t* mixBuffer, size_t sampleCount,
     return;
   }
 
+  if (musicTrackStartPending_)
+  {
+    if (SDL_GetTicks() < musicTrackStartTickMs_)
+    {
+      return;
+    }
+
+    musicTrackStartPending_ = false;
+    musicTrackStartTickMs_ = 0;
+    if (!StartCurrentMusicTrackLocked())
+    {
+      musicGain_ = 0.0f;
+      return;
+    }
+  }
+
   std::vector<int16_t> musicBuffer(sampleCount, 0);
   const int generatedBytes =
       MIX_Generate(musicMixer_, musicBuffer.data(),
@@ -542,6 +578,9 @@ bool AudioOutput::StartCurrentMusicTrackLocked()
     return true;
   }
 
+  musicTrackStartPending_ = false;
+  musicTrackStartTickMs_ = 0;
+
   for (size_t attempts = 0; attempts < musicTracks_.size(); ++attempts)
   {
     MusicTrack& currentTrack = musicTracks_[musicTrackIndex_];
@@ -563,6 +602,12 @@ bool AudioOutput::StartCurrentMusicTrackLocked()
   return true;
 }
 
+void AudioOutput::ScheduleNextMusicTrackLocked()
+{
+  musicTrackStartPending_ = true;
+  musicTrackStartTickMs_ = SDL_GetTicks() + musicTrackGapMs_;
+}
+
 void AudioOutput::AdvanceMusicTrackLocked()
 {
   if (!musicTracks_.empty())
@@ -581,7 +626,7 @@ void AudioOutput::HandleMusicTrackStoppedLocked(MIX_Track* track)
   AdvanceMusicTrackLocked();
   if (musicEnabled_)
   {
-    StartCurrentMusicTrackLocked();
+    ScheduleNextMusicTrackLocked();
   }
 }
 #endif

src/AudioOutput.h

@@ -26,6 +26,7 @@ class AudioOutput
 
   void ConfigureGameFormat(int frequency, int channels);
   bool LoadMusicFilesCsv(const char* csv, std::string* errorMessage);
+  void SetMusicTrackGapMs(Uint64 gapMs);
   void SetMusicEnabled(bool enabled);
   void QueueGameFrames(const int16_t* samples, size_t frameCount);
   void QueueSpeechSamples(const int16_t* samples, size_t sampleCount,
@@ -70,6 +71,7 @@ class AudioOutput
   void DestroyMusicTracksLocked();
   bool ReloadMusicTracksLocked(std::string* errorMessage);
   bool StartCurrentMusicTrackLocked();
+  void ScheduleNextMusicTrackLocked();
   void AdvanceMusicTrackLocked();
   void HandleMusicTrackStoppedLocked(MIX_Track* track);
 #endif
@@ -89,6 +91,9 @@ class AudioOutput
 #if defined(PPUC_HAS_SDL3_MIXER)
   MIX_Mixer* musicMixer_ = nullptr;
   MIX_Track* musicTrack_ = nullptr;
+  bool musicTrackStartPending_ = false;
+  Uint64 musicTrackStartTickMs_ = 0;
+  Uint64 musicTrackGapMs_ = 2000;
 #endif
   size_t musicTrackIndex_ = 0;
   bool musicEnabled_ = false;

src/ppuc.cpp

@@ -254,6 +254,7 @@ bool opt_speech = false;
 bool opt_greeting = false;
 const char* opt_speech_file = NULL;
 const char* opt_music_files = NULL;
+uint32_t opt_music_gap_ms = 2000;
 const char* opt_speech_backend = "auto";
 const char* opt_speech_voice = NULL;
 const char* opt_speech_rate_arg = NULL;
@@ -1332,6 +1333,10 @@ static struct cag_option options[] = {
      .access_name = "music-files",
      .value_name = "VALUE",
      .description = "Comma-separated MP3 playlist for in-game background music (optional)"},
+    {.identifier = 'q',
+     .access_name = "music-gap-ms",
+     .value_name = "VALUE",
+     .description = "Gap between background music tracks in milliseconds (optional, default 2000)"},
     {.identifier = 'U',
      .access_name = "speech-backend",
      .value_name = "VALUE",
@@ -1951,6 +1956,8 @@ int main(int argc, char** argv)
           opt_speech_file = DuplicateOptionalIniString(value);
         else if (key == "MusicFiles")
           opt_music_files = DuplicateOptionalIniString(value);
+        else if (key == "MusicGapMs")
+          opt_music_gap_ms = static_cast<uint32_t>(atoi(value.c_str()));
         else if (key == "Translite")
           opt_translite = DuplicateOptionalIniString(value);
         else if (key == "TransliteAttract")
@@ -2124,6 +2131,9 @@ int main(int argc, char** argv)
       case 'o':
         opt_music_files = cag_option_get_value(&cag_context);
         break;
+      case 'q':
+        opt_music_gap_ms = static_cast<uint32_t>(atoi(cag_option_get_value(&cag_context)));
+        break;
       case 'U':
         opt_speech_backend = cag_option_get_value(&cag_context);
         break;
@@ -2370,6 +2380,7 @@ int main(int argc, char** argv)
       printf("Audio output init failed: %s\n", SDL_GetError());
       return 1;
     }
+    pAudioOutput->SetMusicTrackGapMs(opt_music_gap_ms);
 
     if (HasOptionValue(opt_music_files))
     {