Implement musicdef volume in new mixer

src/audio/gain.cpp

@@ -36,7 +36,7 @@ size_t Gain<C>::filter(tcb::span<Sample<C>> input_buffer, tcb::span<Sample<C>> b
 template <size_t C>
 void Gain<C>::gain(float new_gain)
 {
-	new_gain_ = std::clamp(new_gain, 0.0f, 1.0f);
+	new_gain_ = std::max(new_gain, 0.f);
 }
 
 template <size_t C>

src/i_sound.h

@@ -214,7 +214,8 @@ void I_PauseSong(void);
 */
 void I_ResumeSong(void);
 
-/**	\brief	The I_SetMusicVolume function
+/**	\brief	Sets the volume of the Music mixing channel. Distinguished from the song's individual volume. The scale of
+            the volume is determined by the interface implementation.
 
 	\param	volume	volume to set at
 
@@ -222,6 +223,13 @@ void I_ResumeSong(void);
 */
 void I_SetMusicVolume(int volume);
 
+/** \brief Sets the current song's volume, independent of the overall music channel volume. The volume scale is 0-100,
+ * as a linear gain multiplier. This is distinguished from SetMusicVolume which may or may not be linear.
+*/
+void I_SetCurrentSongVolume(int volume);
+
+// TODO refactor fades to control Song Volume exclusively in tandem with RR musicdef volume multiplier.
+
 boolean I_SetSongTrack(INT32 track);
 
 /// ------------------------

src/s_sound.c

@@ -1360,7 +1360,6 @@ static tic_t     pause_starttic;
 
 musicdef_t *musicdefstart = NULL;
 struct cursongcredit cursongcredit; // Currently displayed song credit info
-int musicdef_volume;
 
 //
 // S_FindMusicDef
@@ -2249,14 +2248,12 @@ void S_ChangeMusicEx(const char *mmusic, UINT16 mflags, boolean looping, UINT32
 		music_flags = mflags;
 		music_looping = looping;
 
-		musicdef_volume = DEFAULT_MUSICDEF_VOLUME;
-
 		{
 			musicdef_t *def = S_FindMusicDef(music_name);
 
 			if (def)
 			{
-				musicdef_volume = def->volume;
+				I_SetCurrentSongVolume(def->volume);
 			}
 		}
 

src/s_sound.h

@@ -38,7 +38,7 @@ extern openmpt_module *openmpt_mhandle;
 #define SOUND_VOLUME_RANGE 256
 #define MAX_SOUND_VOLUME 255
 
-#define DEFAULT_MUSICDEF_VOLUME ( 100 / VOLUME_DIVIDER )
+#define DEFAULT_MUSICDEF_VOLUME 100
 
 extern consvar_t stereoreverse;
 extern consvar_t cv_soundvolume, cv_closedcaptioning, cv_digmusicvolume; 
@@ -197,7 +197,6 @@ extern struct cursongcredit
 } cursongcredit;
 
 extern musicdef_t *musicdefstart;
-extern int musicdef_volume;
 
 void S_LoadMusicDefs(UINT16 wadnum);
 void S_InitMusicDefs(void);

src/sdl/new_sound.cpp

@@ -57,7 +57,8 @@ static shared_ptr<Mixer<2>> mixer_sound_effects;
 static shared_ptr<Mixer<2>> mixer_music;
 static shared_ptr<MusicPlayer> music_player;
 static shared_ptr<Gain<2>> gain_sound_effects;
-static shared_ptr<Gain<2>> gain_music;
+static shared_ptr<Gain<2>> gain_music_player;
+static shared_ptr<Gain<2>> gain_music_channel;
 
 static vector<shared_ptr<SoundEffectPlayer>> sound_effect_channels;
 
@@ -187,12 +188,14 @@ void initialize_sound()
 		mixer_music = make_shared<Mixer<2>>();
 		music_player = make_shared<MusicPlayer>();
 		gain_sound_effects = make_shared<Gain<2>>();
-		gain_music = make_shared<Gain<2>>();
+		gain_music_player = make_shared<Gain<2>>();
+		gain_music_channel = make_shared<Gain<2>>();
 		gain_sound_effects->bind(mixer_sound_effects);
-		gain_music->bind(mixer_music);
+		gain_music_player->bind(music_player);
+		gain_music_channel->bind(mixer_music);
 		master->add_source(gain_sound_effects);
-		master->add_source(gain_music);
-		mixer_music->add_source(music_player);
+		master->add_source(gain_music_channel);
+		mixer_music->add_source(gain_music_player);
 		for (size_t i = 0; i < static_cast<size_t>(cv_numChannels.value); i++)
 		{
 			shared_ptr<SoundEffectPlayer> player = make_shared<SoundEffectPlayer>();
@@ -356,7 +359,7 @@ void I_SetSfxVolume(int volume)
 
 	if (gain_sound_effects)
 	{
-		gain_sound_effects->gain(vol * vol * vol);
+		gain_sound_effects->gain(std::clamp(vol * vol * vol, 0.f, 1.f));
 	}
 }
 
@@ -597,6 +600,12 @@ boolean I_LoadSong(char* data, size_t len)
 		return false;
 	}
 
+	if (gain_music_player)
+	{
+		// Reset song volume to 1.0 for newly loaded songs.
+		gain_music_player->gain(1.0);
+	}
+
 	return true;
 }
 
@@ -663,9 +672,22 @@ void I_SetMusicVolume(int volume)
 {
 	float vol = static_cast<float>(volume) / 100.f;
 
-	if (gain_music)
+	if (gain_music_channel)
 	{
-		gain_music->gain(vol * vol * vol);
+		// Music channel volume is interpreted as logarithmic rather than linear.
+		// We approximate by cubing the gain level so vol 50 roughly sounds half as loud.
+		gain_music_channel->gain(std::clamp(vol * vol * vol, 0.f, 1.f));
+	}
+}
+
+void I_SetCurrentSongVolume(int volume)
+{
+	float vol = static_cast<float>(volume) / 100.f;
+
+	if (gain_music_player)
+	{
+		// However, different from music channel volume, musicdef volumes are explicitly linear.
+		gain_music_player->gain(std::max(vol, 0.f));
 	}
 }