Added ability to control the gaining factor on the fly

The gaining factor is an independent to the regular volume and has goal to adjust the volume of too quite or too loud music source, and unlike the volume setting, it is a multiplication factor that has no upper limit.

CHANGES.X.txt

@@ -10,6 +10,7 @@ It is an additional changelog file. It extends the CHANGES.txt that lists change
  * Added the ability to hook the file path opener.
  * Fixed the detection of some MP3 files and improved the performance on low-end platforms.
  * Fixed the inability to open PXTONE files when output has more than two channels.
+ * Added an ability to change the gaining factor on the fly (Added Mix_SetMusicGain() and Mix_GetMusicGain() calls)
 
 2.6.0: (2023-11-23)
  * Added new calls: Mix_ADLMIDI_getAutoArpeggio(), Mix_ADLMIDI_setAutoArpeggio(), Mix_OPNMIDI_getAutoArpeggio(), Mix_OPNMIDI_setAutoArpeggio(), Mix_QuerySpec(), Mix_SetMusicSpeed(), Mix_GetMusicSpeed(), Mix_SetMusicPitch(), Mix_GetMusicPitch(), Mix_GME_SetSpcEchoDisabled(), Mix_GME_GetSpcEchoDisabled()

examples/MusPlay-Qt/MainWindow/musplayer_qt.cpp

@@ -254,9 +254,11 @@ void MusPlayer_Qt::contextMenu(const QPoint &pos)
     QAction *echo         = x.addAction("Echo");
     QAction *echoTuner    = x.addAction("Echo tuner...");
     QAction *musicFX      = x.addAction("Music FX...");
+    QAction *resetGain   = x.addAction("Reset gain");
     QAction *resetTempo   = x.addAction("Reset tempo");
     QAction *resetSpeed   = x.addAction("Reset speed");
     QAction *resetPitch   = x.addAction("Reset pitch");
+    resetGain->setEnabled(ui->gainFrame->isEnabled());
     resetTempo->setEnabled(ui->tempoFrame->isEnabled());
     resetSpeed->setEnabled(ui->speedFrame->isEnabled());
     resetPitch->setEnabled(ui->pitchFrame->isEnabled());
@@ -307,6 +309,8 @@ void MusPlayer_Qt::contextMenu(const QPoint &pos)
         on_actionTuneEcho_triggered();
     else if(musicFX == ret)
         on_actionMusicFX_triggered();
+    else if(resetGain == ret)
+        ui->gain->setValue(m_setupMidi->getGainDefault());
     else if(resetTempo == ret)
         ui->tempo->setValue(0);
     else if(resetSpeed == ret)
@@ -445,20 +449,34 @@ void MusPlayer_Qt::on_play_clicked()
 
     if(PGE_MusicPlayer::openFile(musicPath))
     {
+        float gain = Mix_GetMusicGain(PGE_MusicPlayer::s_playMus);
+        int gainDefault = gain >= 0.0f ? static_cast<int>(gain * 100): 100;
+        double tempo = Mix_GetMusicTempo(PGE_MusicPlayer::s_playMus);
+        double speed = Mix_GetMusicSpeed(PGE_MusicPlayer::s_playMus);
+        double pitch = Mix_GetMusicPitch(PGE_MusicPlayer::s_playMus);
+
+        m_setupMidi->setGainDefault(gainDefault);
+        m_setupMidi->setGain(gainDefault);
+
+        ui->gain->blockSignals(true);
+        ui->gain->setValue(gainDefault);
+        ui->gain->blockSignals(false);
+        ui->gainFrame->setEnabled(gain >= 0.0f);
+
         ui->tempo->blockSignals(true);
         ui->tempo->setValue(0);
         ui->tempo->blockSignals(false);
-        ui->tempoFrame->setEnabled(Mix_GetMusicTempo(PGE_MusicPlayer::s_playMus) >= 0.0);
+        ui->tempoFrame->setEnabled(tempo >= 0.0);
 
         ui->speed->blockSignals(true);
         ui->speed->setValue(0);
         ui->speed->blockSignals(false);
-        ui->speedFrame->setEnabled(Mix_GetMusicSpeed(PGE_MusicPlayer::s_playMus) >= 0.0);
+        ui->speedFrame->setEnabled(speed >= 0.0);
 
         ui->pitch->blockSignals(true);
         ui->pitch->setValue(0);
         ui->pitch->blockSignals(false);
-        ui->pitchFrame->setEnabled(Mix_GetMusicPitch(PGE_MusicPlayer::s_playMus) >= 0.0);
+        ui->pitchFrame->setEnabled(pitch >= 0.0);
 
         PGE_MusicPlayer::changeVolume(ui->volume->value());
         playSuccess = PGE_MusicPlayer::playMusic();
@@ -598,6 +616,22 @@ void MusPlayer_Qt::on_disableSpcEcho_clicked(bool checked)
     Mix_GME_SetSpcEchoDisabled(PGE_MusicPlayer::s_playMus, checked ? 1 : 0);
 }
 
+void MusPlayer_Qt::on_gain_valueChanged(int gain)
+{
+#ifdef SDL_MIXER_X
+    if(Mix_PlayingMusicStream(PGE_MusicPlayer::s_playMus))
+    {
+        float gainFactor = 0.01 * float(gain);
+        Mix_SetMusicGain(PGE_MusicPlayer::s_playMus, gainFactor);
+        qDebug() << "Changed gain factor: " << gainFactor;
+        QToolTip::showText(QCursor::pos(), QString("%1").arg(gainFactor), this);
+        m_setupMidi->setGain(gain);
+    }
+#else
+    Q_UNUSED(gain);
+#endif
+}
+
 void MusPlayer_Qt::on_tempo_valueChanged(int tempo)
 {
 #ifdef SDL_MIXER_X

examples/MusPlay-Qt/MainWindow/musplayer_qt.h

@@ -80,6 +80,7 @@ private slots:
     void on_trackNext_clicked();
     void on_disableSpcEcho_clicked(bool checked);
 
+    void on_gain_valueChanged(int tempo);
     void on_tempo_valueChanged(int tempo);
     void on_speed_valueChanged(int speed);
     void on_pitch_valueChanged(int pitch);