Improve core.sound_play with ephemeral sounds and player exclusion

doc/lua_api.txt

@@ -826,7 +826,7 @@ Examples of sound parameter tables:
         gain = 1.0,  -- default
         loop = true,
     }
-    -- Play in a location
+    -- Play at a location
     {
         pos = {x = 1, y = 2, z = 3},
         gain = 1.0,  -- default
@@ -839,13 +839,22 @@ Examples of sound parameter tables:
         max_hear_distance = 32,  -- default, uses an euclidean metric
         loop = true,
     }
+    -- Play at a location, heard by anyone *but* the given player
+    {
+        pos = {x = 32, y = 0, z = 100},
+        max_hear_distance = 40,
+        exclude_player = name,
+    }
 
 Looped sounds must either be connected to an object or played locationless to
-one player using `to_player = name,`.
+one player using `to_player = name`.
 
 A positional sound will only be heard by players that are within
 `max_hear_distance` of the sound position, at the start of the sound.
 
+`exclude_player = name` can be applied to locationless, positional and object-
+bound sounds to exclude a single player from hearing them.
+
 `SimpleSoundSpec`
 -----------------
 
@@ -4929,10 +4938,15 @@ Defaults for the `on_punch` and `on_dig` node definition callbacks
 Sounds
 ------
 
-* `minetest.sound_play(spec, parameters)`: returns a handle
+* `minetest.sound_play(spec, parameters, [ephemeral])`: returns a handle
     * `spec` is a `SimpleSoundSpec`
     * `parameters` is a sound parameter table
+    * `ephemeral` is a boolean (default: false)
+      Ephemeral sounds will not return a handle and can't be stopped or faded.
+      It is recommend to use this for short sounds that happen in response to
+      player actions (e.g. door closing).
 * `minetest.sound_stop(handle)`
+    * `handle` is a handle returned by `minetest.sound_play`
 * `minetest.sound_fade(handle, step, gain)`
     * `handle` is a handle returned by `minetest.sound_play`
     * `step` determines how fast a sound will fade.

src/client/client.cpp

@@ -1106,7 +1106,7 @@ void Client::sendRemovedSounds(std::vector<s32> &soundList)
 
 	pkt << (u16) (server_ids & 0xFFFF);
 
-	for (int sound_id : soundList)
+	for (s32 sound_id : soundList)
 		pkt << sound_id;
 
 	Send(&pkt);

src/client/client.h

@@ -561,7 +561,7 @@ private:
 	std::unordered_map<s32, int> m_sounds_server_to_client;
 	// And the other way!
 	std::unordered_map<int, s32> m_sounds_client_to_server;
-	// And relations to objects
+	// Relation of client id to object id
 	std::unordered_map<int, u16> m_sounds_to_objects;
 
 	// Map server hud ids to client hud ids

src/network/clientpackethandler.cpp

@@ -778,6 +778,7 @@ void Client::handleCommand_PlaySound(NetworkPacket* pkt)
 		[25 + len] bool loop
 		[26 + len] f32 fade
 		[30 + len] f32 pitch
+		[34 + len] bool ephemeral
 	*/
 
 	s32 server_id;
@@ -790,12 +791,14 @@ void Client::handleCommand_PlaySound(NetworkPacket* pkt)
 	bool loop;
 	float fade = 0.0f;
 	float pitch = 1.0f;
+	bool ephemeral = false;
 
 	*pkt >> server_id >> name >> gain >> type >> pos >> object_id >> loop;
 
 	try {
 		*pkt >> fade;
 		*pkt >> pitch;
+		*pkt >> ephemeral;
 	} catch (PacketError &e) {};
 
 	// Start playing
@@ -813,7 +816,6 @@ void Client::handleCommand_PlaySound(NetworkPacket* pkt)
 			if (cao)
 				pos = cao->getPosition();
 			client_id = m_sound->playSoundAt(name, loop, gain, pos, pitch);
-			// TODO: Set up sound to move with object
 			break;
 		}
 		default:
@@ -821,8 +823,11 @@ void Client::handleCommand_PlaySound(NetworkPacket* pkt)
 	}
 
 	if (client_id != -1) {
+		// for ephemeral sounds, server_id is not meaningful
+		if (!ephemeral) {
 			m_sounds_server_to_client[server_id] = client_id;
 			m_sounds_client_to_server[client_id] = server_id;
+		}
 		if (object_id != 0)
 			m_sounds_to_objects[client_id] = object_id;
 	}

src/network/networkprotocol.h

@@ -200,6 +200,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 		Unknown inventory serialization fields no longer throw an error
 		Mod-specific formspec version
 		Player FOV override API
+		"ephemeral" added to TOCLIENT_PLAY_SOUND
 */
 
 #define LATEST_PROTOCOL_VERSION 38
@@ -450,6 +451,7 @@ enum ToClientCommand
 		s32[3] pos_nodes*10000
 		u16 object_id
 		u8 loop (bool)
+		u8 ephemeral (bool)
 	*/
 
 	TOCLIENT_STOP_SOUND = 0x40,

src/script/common/c_content.cpp

@@ -1019,6 +1019,7 @@ void read_server_sound_params(lua_State *L, int index,
 		params.max_hear_distance = BS*getfloatfield_default(L, index,
 				"max_hear_distance", params.max_hear_distance/BS);
 		getboolfield(L, index, "loop", params.loop);
+		getstringfield(L, index, "exclude_player", params.exclude_player);
 	}
 }
 

src/script/lua_api/l_server.cpp

@@ -429,7 +429,7 @@ int ModApiServer::l_get_worldpath(lua_State *L)
 	return 1;
 }
 
-// sound_play(spec, parameters)
+// sound_play(spec, parameters, [ephemeral])
 int ModApiServer::l_sound_play(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
@@ -437,8 +437,14 @@ int ModApiServer::l_sound_play(lua_State *L)
 	read_soundspec(L, 1, spec);
 	ServerSoundParams params;
 	read_server_sound_params(L, 2, params);
+	bool ephemeral = lua_gettop(L) > 2 && readParam<bool>(L, 3);
+	if (ephemeral) {
+		getServer(L)->playSound(spec, params, true);
+		lua_pushnil(L);
+	} else {
 		s32 handle = getServer(L)->playSound(spec, params);
 		lua_pushinteger(L, handle);
+	}
 	return 1;
 }
 
@@ -446,7 +452,7 @@ int ModApiServer::l_sound_play(lua_State *L)
 int ModApiServer::l_sound_stop(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
-	int handle = luaL_checkinteger(L, 1);
+	s32 handle = luaL_checkinteger(L, 1);
 	getServer(L)->stopSound(handle);
 	return 0;
 }

src/server.cpp

@@ -2013,8 +2013,18 @@ void Server::SendPlayerSpeed(session_t peer_id, const v3f &added_vel)
 	Send(&pkt);
 }
 
+inline s32 Server::nextSoundId()
+{
+	s32 ret = m_next_sound_id;
+	if (m_next_sound_id == INT32_MAX)
+		m_next_sound_id = 0; // signed overflow is undefined
+	else
+		m_next_sound_id++;
+	return ret;
+}
+
 s32 Server::playSound(const SimpleSoundSpec &spec,
-		const ServerSoundParams &params)
+		const ServerSoundParams &params, bool ephemeral)
 {
 	// Find out initial position of sound
 	bool pos_exists = false;
@@ -2025,7 +2035,7 @@ s32 Server::playSound(const SimpleSoundSpec &spec,
 
 	// Filter destination clients
 	std::vector<session_t> dst_clients;
-	if(!params.to_player.empty()) {
+	if (!params.to_player.empty()) {
 		RemotePlayer *player = m_env->getPlayer(params.to_player.c_str());
 		if(!player){
 			infostream<<"Server::playSound: Player \""<<params.to_player
@@ -2045,6 +2055,9 @@ s32 Server::playSound(const SimpleSoundSpec &spec,
 			RemotePlayer *player = m_env->getPlayer(client_id);
 			if (!player)
 				continue;
+			if (!params.exclude_player.empty() &&
+					params.exclude_player == player->getName())
+				continue;
 
 			PlayerSAO *sao = player->getPlayerSAO();
 			if (!sao)
@@ -2063,27 +2076,32 @@ s32 Server::playSound(const SimpleSoundSpec &spec,
 		return -1;
 
 	// Create the sound
-	s32 id = m_next_sound_id++;
+	s32 id;
+	ServerPlayingSound *psound = nullptr;
+	if (ephemeral) {
+		id = -1; // old clients will still use this, so pick a reserved ID
+	} else {
+		id = nextSoundId();
 		// The sound will exist as a reference in m_playing_sounds
 		m_playing_sounds[id] = ServerPlayingSound();
-	ServerPlayingSound &psound = m_playing_sounds[id];
-	psound.params = params;
-	psound.spec = spec;
+		psound = &m_playing_sounds[id];
+		psound->params = params;
+		psound->spec = spec;
+	}
 
 	float gain = params.gain * spec.gain;
 	NetworkPacket pkt(TOCLIENT_PLAY_SOUND, 0);
 	pkt << id << spec.name << gain
 			<< (u8) params.type << pos << params.object
-			<< params.loop << params.fade << params.pitch;
+			<< params.loop << params.fade << params.pitch
+			<< ephemeral;
 
-	// Backwards compability
-	bool play_sound = gain > 0;
+	bool as_reliable = !ephemeral;
 
 	for (const u16 dst_client : dst_clients) {
-		if (play_sound || m_clients.getProtocolVersion(dst_client) >= 32) {
-			psound.clients.insert(dst_client);
-			m_clients.send(dst_client, 0, &pkt, true);
-		}
+		if (psound)
+			psound->clients.insert(dst_client);
+		m_clients.send(dst_client, 0, &pkt, as_reliable);
 	}
 	return id;
 }

src/server.h

@@ -98,6 +98,7 @@ struct ServerSoundParams
 	v3f pos;
 	u16 object = 0;
 	std::string to_player = "";
+	std::string exclude_player = "";
 
 	v3f getPos(ServerEnvironment *env, bool *pos_exists) const;
 };
@@ -209,7 +210,8 @@ public:
 
 	// Returns -1 if failed, sound handle on success
 	// Envlock
-	s32 playSound(const SimpleSoundSpec &spec, const ServerSoundParams &params);
+	s32 playSound(const SimpleSoundSpec &spec, const ServerSoundParams &params,
+			bool ephemeral=false);
 	void stopSound(s32 handle);
 	void fadeSound(s32 handle, float step, float gain);
 
@@ -646,7 +648,8 @@ private:
 		Sounds
 	*/
 	std::unordered_map<s32, ServerPlayingSound> m_playing_sounds;
-	s32 m_next_sound_id = 0;
+	s32 m_next_sound_id = 0; // positive values only
+	s32 nextSoundId();
 
 	/*
 		Detached inventories (behind m_env_mutex)