Music and playlists

* This PR is a revival of endless-sky#7538.
* Authorship from prior code review is preserved.

Feature Summary
---------------

Adds the possibility to add playlists to the game that are only played in certain locations and if certain conditions are met.

Example:

```ruby
track "test2"
        volume 0.1 #add 0.1 to volume
	idle "music/mainscreen" #idle track, played during normal gameplay
	combat "music/mainscreen" #combat track, played during combat
	landing "music/mainscreen" #landing track, played while landed

track "test1"
	idle "music/haispace"
	combat "music/haispace"
	landing "music/haispace"

playlist "test"
        to play #conditions for playing this playlist
                has "Hai Intro: done"
	location #locationfilter for where to play this
		not government "Hai"
	priority 1 #the priority, higher priority playlist will be chosen over lower priority playlists
	weight 10 #the weight of a playlist inside of its priority layer, higher weight means more probable to be chosen
	tracks "linear"
		"test1" 20
		"test2" 20
```

Detailed Explanation
--------------------

`track NAME` holds the following child keys.

* `NAME` the name of the track
* `volume` (default 0): a value that should be chosen between -1 and 1 that gets added to the current volume of the music. (use this with small values, otherwise users who want dim music will be annoyed.)
* Three categories of music associated with this track. The tracks will be played when the player is in their state. If one is not given, nothing will be played in that state.
  * `idle`
  * `combat`
  * `landing`

`playlist NAME` holds the following child keys.

* `NAME` the name of the playlist.
* `to play` conditions that determine if this playlist can be played.
* A `location` filter for where this playlist will be played.
* A `priority`, higher priorities will always play over lower priorities.
* A `weight`, playlists with higher weight are more likely to be played inside the same priority.
* `tracks`
  * A progression style: `linear`, `random`, or `pick` (pick means that one track will be picked and repeated until the playlist is switched)
  * Various tracks with weights to them, weights only matter for pick or random progression style.

This would play either track one or track two when you are not in Hai government zone.

Testing Done
------------

TBD

Important
---------

* Asset pull request: endless-sky/endless-sky-assets#127

Checklist
---------

- [ ] Update with upstream master including CMake.
- [ ] Do some testing.

Co-authored-by: Hurleveur <[email protected]>
Co-authored-by: tibetiroka <[email protected]>

EndlessSky.xcodeproj/project.pbxproj

@@ -12,6 +12,8 @@
 		03DC4253AA8390FE0A8FB4EA /* MaskManager.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 499B4DA7A9C7351120660643 /* MaskManager.cpp */; };
 		072599D126A8CB2F007EC229 /* SDL2.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 072599CC26A8C942007EC229 /* SDL2.framework */; };
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+		0E77AFDF2918751D00864BB5 /* Playlist.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0E77AFDE2918751300864BB5 /* Playlist.cpp */; };
+		0E77AFE02918751D00864BB5 /* Track.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0E77AFDC2918751300864BB5 /* Track.cpp */; };
 		1578F883250B5F8A00D318FB /* InfoPanelState.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 1578F880250B5F8A00D318FB /* InfoPanelState.cpp */; };
 		16AD4CACA629E8026777EA00 /* truncate.hpp in Headers */ = {isa = PBXBuildFile; fileRef = 2CA44855BD0AFF45DCAEEA5D /* truncate.hpp */; settings = {ATTRIBUTES = (Project, ); }; };
 		1F884DB590D5152608510676 /* ShipJumpNavigation.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 13B64DB8AE730E57C3DEA2F0 /* ShipJumpNavigation.cpp */; };
@@ -228,6 +230,10 @@
 		086E48E490C9BAD6660C7274 /* ExclusiveItem.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = ExclusiveItem.h; path = source/ExclusiveItem.h; sourceTree = "<group>"; };
 		0C90483BB01ECD0E3E8DDA44 /* WeightedList.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = WeightedList.h; path = source/WeightedList.h; sourceTree = "<group>"; };
 		0DF34095B64BC64F666ECF5F /* CoreStartData.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = CoreStartData.cpp; path = source/CoreStartData.cpp; sourceTree = "<group>"; };
+		0E77AFDB2918751300864BB5 /* Playlist.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = Playlist.h; path = source/Playlist.h; sourceTree = "<group>"; };
+		0E77AFDC2918751300864BB5 /* Track.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; name = Track.cpp; path = source/Track.cpp; sourceTree = "<group>"; };
+		0E77AFDD2918751300864BB5 /* Track.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = Track.h; path = source/Track.h; sourceTree = "<group>"; };
+		0E77AFDE2918751300864BB5 /* Playlist.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; name = Playlist.cpp; path = source/Playlist.cpp; sourceTree = "<group>"; };
 		11EA4AD7A889B6AC1441A198 /* StartConditionsPanel.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = StartConditionsPanel.cpp; path = source/StartConditionsPanel.cpp; sourceTree = "<group>"; };
 		13B643F6BEC24349F9BC9F42 /* alignment.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = alignment.hpp; path = source/text/alignment.hpp; sourceTree = "<group>"; };
 		13B64DB8AE730E57C3DEA2F0 /* ShipJumpNavigation.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = ShipJumpNavigation.cpp; path = source/ShipJumpNavigation.cpp; sourceTree = "<group>"; };
@@ -591,6 +597,10 @@
 		654D33611BE92C9200D1E5AB /* source */ = {
 			isa = PBXGroup;
 			children = (
+				0E77AFDE2918751300864BB5 /* Playlist.cpp */,
+				0E77AFDB2918751300864BB5 /* Playlist.h */,
+				0E77AFDC2918751300864BB5 /* Track.cpp */,
+				0E77AFDD2918751300864BB5 /* Track.h */,
 				A96862CD1AE6FD0A004FE1FE /* Account.cpp */,
 				A96862CE1AE6FD0A004FE1FE /* Account.h */,
 				A96862CF1AE6FD0A004FE1FE /* AI.cpp */,
@@ -1155,6 +1165,8 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				0E77AFDF2918751D00864BB5 /* Playlist.cpp in Sources */,
+				0E77AFE02918751D00864BB5 /* Track.cpp in Sources */,
 				A96863AD1AE6FD0E004FE1FE /* Command.cpp in Sources */,
 				A96863E71AE6FD0E004FE1FE /* PointerShader.cpp in Sources */,
 				A96863E51AE6FD0E004FE1FE /* PlayerInfo.cpp in Sources */,

EndlessSkyLib.cbp

@@ -269,6 +269,8 @@
 		<Unit filename="source/PlayerInfo.h" />
 		<Unit filename="source/PlayerInfoPanel.cpp" />
 		<Unit filename="source/PlayerInfoPanel.h" />
+		<Unit filename="source/Playlist.cpp" />
+		<Unit filename="source/Playlist.h" />
 		<Unit filename="source/Point.cpp" />
 		<Unit filename="source/Point.h" />
 		<Unit filename="source/PointerShader.cpp" />
@@ -379,6 +381,8 @@
 		<Unit filename="source/text/Format.h" />
 		<Unit filename="source/text/Table.cpp" />
 		<Unit filename="source/text/Table.h" />
+		<Unit filename="source/text/Track.cpp" />
+		<Unit filename="source/text/Track.h" />
 		<Unit filename="source/text/Utf8.cpp" />
 		<Unit filename="source/text/Utf8.h" />
 		<Unit filename="source/text/WrappedText.cpp" />

data/interfaces.txt

@@ -372,6 +372,8 @@ interface "load menu"
 interface "controls"
 	sprite "ui/keys panel"
 		center -65 -20
+	sprite "ui/music volume"
+		center 330 -60
 	button c "_Controls"
 		center -300 -230
 		dimensions 90 30
@@ -455,6 +457,11 @@ interface "preferences"
 		dimensions 0 -200
 		color "energy"
 		size 3
+	bar "music volume"
+		from 325 15
+		dimensions 0 -200
+		color "energy"
+		size 3
 
 
 

source/Audio.cpp

@@ -16,11 +16,17 @@ this program. If not, see <https://www.gnu.org/licenses/>.
 #include "Audio.h"
 
 #include "Files.h"
+#include "GameData.h"
 #include "Logger.h"
 #include "Music.h"
+#include "Planet.h"
+#include "PlayerInfo.h"
+#include "Playlist.h"
 #include "Point.h"
+#include "Preferences.h"
 #include "Random.h"
 #include "Sound.h"
+#include "System.h"
 
 #if !defined(__APPLE__) || defined(ES_CMAKE)
 #include <AL/al.h>
@@ -115,6 +121,12 @@ namespace {
 	shared_ptr<Music> previousTrack;
 	int musicFade = 0;
 	vector<int16_t> fadeBuffer;
+	double musicVolume = 1.;
+	double musicVolumeModifier = 0.;
+
+	const Playlist *currentPlaylist = nullptr;
+	const Track *currentPlaylistTrack = nullptr;
+	Track::GameState oldState = Track::GameState::IDLE;
 }
 
 
@@ -181,6 +193,7 @@ void Audio::Init(const vector<string> &sources)
 	}
 	alSourceQueueBuffers(musicSource, MUSIC_BUFFERS, musicBuffers);
 	alSourcePlay(musicSource);
+	alSourcef(musicSource, AL_GAIN, musicVolume);
 }
 
 
@@ -233,6 +246,24 @@ void Audio::SetVolume(double level)
 
 
 
+// Get the volume.
+double Audio::MusicVolume()
+{
+	return musicVolume;
+}
+
+
+
+// Set the volume (to a value between 0 and 1).
+void Audio::SetMusicVolume(double level)
+{
+	musicVolume = min(1., max(0., level));
+	if(isInitialized)
+		alSourcef(musicSource, AL_GAIN, min(1., musicVolume + musicVolumeModifier));
+}
+
+
+
 // Get a pointer to the named sound. The name is the path relative to the
 // "sound/" folder, and without ~ if it's on the end, or the extension.
 const Sound *Audio::Get(const string &name)
@@ -260,6 +291,90 @@ void Audio::Update(const Point &listenerPosition)
 
 
 
+void Audio::UpdateMusic(PlayerInfo &player, Track::GameState state)
+{
+	if(!isInitialized)
+		return;
+
+	// Music defined by planet
+	if(state == Track::GameState::LANDED)
+	{
+		if(!player.GetPlanet()->MusicName().empty())
+		{
+			PlayMusic(player.GetPlanet()->MusicName());
+			return;
+		}
+	}
+	else
+	{
+		if(player.GetSystem()->MusicName().empty())
+		{
+			PlayMusic(player.GetSystem()->MusicName());
+			return;
+		}
+	}
+
+	// If the current playlists conditions are not matching anymore, search a new one.
+	bool currentPlaylistValid = currentPlaylist ?
+		currentPlaylist->MatchingConditions(player) : false;
+	// The track has to be updated if the current track is finished or the playlist is not matching
+	// anymore.
+	if(currentTrack->IsFinished() || !currentPlaylistValid)
+	{
+		if(!currentPlaylistValid)
+		{
+			// If the current playlist is not valid, find a new one based on priority and weight.
+			WeightedList<const Playlist *> validPlaylists;
+			int priority = 0;
+			for(auto &playlist : GameData::Playlists())
+				if(playlist.second.MatchingConditions(player))
+				{
+					// Higher priorities always win.
+					if(playlist.second.Priority() == priority)
+						validPlaylists.emplace_back(playlist.second.Weight(), &playlist.second);
+					else if(playlist.second.Priority() > priority)
+					{
+						priority = playlist.second.Priority();
+						validPlaylists.clear();
+						validPlaylists.emplace_back(playlist.second.Weight(), &playlist.second);
+					}
+				}
+			if(!validPlaylists.empty())
+			{
+				// This will return a random playlist, with playlist with a higher weight being more
+				// probable to be returned.
+				currentPlaylist = validPlaylists.Get();
+				currentPlaylist->Activate();
+			}
+			else
+				currentPlaylist = nullptr;
+		}
+		// Only switch to a new track if a playlist is set.
+		if(currentPlaylist)
+		{
+			currentPlaylistTrack = currentPlaylist->GetCurrentTrack();
+			if(currentPlaylistTrack)
+			{
+				musicVolumeModifier = currentPlaylistTrack->GetVolumeModifier();
+				SetMusicVolume(volume);
+				PlayMusic(currentPlaylistTrack->GetTitle(state));
+			}
+			oldState = state;
+		}
+		// If no playlist is set this means nothing should be played, so stop everything.
+		else
+			currentTrack->Finish();
+	}
+	if(oldState != state)
+	{
+		oldState = state;
+		if(currentPlaylistTrack)
+			PlayMusic(currentPlaylistTrack->GetTitle(state));
+	}
+}
+
+
+
 // Play the given sound, at full volume.
 void Audio::Play(const Sound *sound)
 {
@@ -301,6 +416,9 @@ void Audio::PlayMusic(const string &name)
 	// Don't worry about thread safety here, since music will always be started
 	// by the main thread.
 	musicFade = 65536;
+	// Clear of the previous track so that we can use it again without having
+	// old data to deal with.
+	previousTrack.reset(new Music());
 	swap(currentTrack, previousTrack);
 	// If the name is empty, it means to turn music off.
 	currentTrack->SetSource(name);

source/Audio.h

@@ -16,9 +16,12 @@ this program. If not, see <https://www.gnu.org/licenses/>.
 #ifndef AUDIO_H_
 #define AUDIO_H_
 
+#include "Track.h"
+
 #include <string>
 #include <vector>
 
+class PlayerInfo;
 class Point;
 class Sound;
 
@@ -44,6 +47,10 @@ class Audio {
 	static double Volume();
 	static void SetVolume(double level);
 
+	// Get or set the music volume (between 0 and 1).
+	static double MusicVolume();
+	static void SetMusicVolume(double level);
+
 	// Get a pointer to the named sound. The name is the path relative to the
 	// "sound/" folder, and without ~ if it's on the end, or the extension.
 	// Do not call this function until Progress() is 100%.
@@ -53,6 +60,7 @@ class Audio {
 	// added but deferred because they were added from a thread other than the
 	// main one (the one that called Init()).
 	static void Update(const Point &listenerPosition);
+	static void UpdateMusic(PlayerInfo &player, Track::GameState state);
 
 	// Play the given sound, at full volume.
 	static void Play(const Sound *sound);

source/CMakeLists.txt

@@ -254,6 +254,8 @@ target_sources(EndlessSkyLib PRIVATE
 	PlayerInfo.h
 	PlayerInfoPanel.cpp
 	PlayerInfoPanel.h
+	Playlist.cpp
+	Playlist.h
 	Point.cpp
 	Point.h
 	PointerShader.cpp
@@ -329,6 +331,8 @@ target_sources(EndlessSkyLib PRIVATE
 	TestData.h
 	TextReplacements.cpp
 	TextReplacements.h
+	Track.cpp
+	Track.h
 	Trade.cpp
 	Trade.h
 	TradingPanel.cpp

source/Engine.cpp

@@ -63,6 +63,7 @@ this program. If not, see <https://www.gnu.org/licenses/>.
 #include "System.h"
 #include "Test.h"
 #include "TestContext.h"
+#include "Track.h"
 #include "Visual.h"
 #include "Weather.h"
 #include "Wormhole.h"
@@ -511,6 +512,16 @@ void Engine::Step(bool isActive)
 	wasActive = isActive;
 	Audio::Update(center);
 
+	if(GameData::IsLoaded())
+	{
+		Track::GameState state = Track::GameState::IDLE;
+		// If there are hostile ships in the system, set the state to COMBAT.
+		if(hadHostiles)
+			state = Track::GameState::COMBAT;
+		Audio::UpdateMusic(player, state);
+	}
+
+
 	// Update the zoom value now that the calculation thread is paused.
 	if(nextZoom)
 	{
@@ -1212,7 +1223,6 @@ void Engine::EnterSystem()
 	const Date &today = player.GetDate();
 
 	const System *system = flagship->GetSystem();
-	Audio::PlayMusic(system->MusicName());
 	GameData::SetHaze(system->Haze(), false);
 
 	Messages::Add("Entering the " + system->Name() + " system on "

source/GameData.cpp

@@ -609,6 +609,13 @@ const Set<Planet> &GameData::Planets()
 
 
 
+const Set<Playlist> &GameData::Playlists()
+{
+	return objects.playlists;
+}
+
+
+
 const Set<Ship> &GameData::Ships()
 {
 	return objects.ships;
@@ -630,6 +637,13 @@ const Set<TestData> &GameData::TestDataSets()
 
 
 
+const Set<Track> &GameData::Tracks()
+{
+	return objects.tracks;
+}
+
+
+
 ConditionsStore &GameData::GlobalConditions()
 {
 	return globalConditions;

source/GameData.h

@@ -51,6 +51,7 @@ class Panel;
 class Person;
 class Phrase;
 class Planet;
+class Playlist;
 class Politics;
 class Ship;
 class Sprite;
@@ -60,6 +61,7 @@ class System;
 class Test;
 class TestData;
 class TextReplacements;
+class Track;
 class Wormhole;
 
 
@@ -129,11 +131,13 @@ class GameData {
 	static const Set<Person> &Persons();
 	static const Set<Phrase> &Phrases();
 	static const Set<Planet> &Planets();
+	static const Set<Playlist> &Playlists();
 	static const Set<Ship> &Ships();
 	static const Set<Sale<Ship>> &Shipyards();
 	static const Set<System> &Systems();
 	static const Set<Test> &Tests();
 	static const Set<TestData> &TestDataSets();
+	static const Set<Track> &Tracks();
 	static const Set<Wormhole> &Wormholes();
 
 	static ConditionsStore &GlobalConditions();

source/MenuPanel.cpp

@@ -78,7 +78,7 @@ MenuPanel::MenuPanel(PlayerInfo &player, UI &gamePanels)
 	}
 
 	if(player.GetPlanet())
-		Audio::PlayMusic(player.GetPlanet()->MusicName());
+		Audio::UpdateMusic(player, Track::GameState::LANDED);
 }