Add event manager and use it to trigger sounds

15 files changed, 388 insertions, 14 deletions

diff --git a/games/mesetint/mods/default/init.lua b/games/mesetint/mods/default/init.lua
index c850597ba..0041e3588 100644
--- a/games/mesetint/mods/default/init.lua
+++ b/games/mesetint/mods/default/init.lua
@@ -654,6 +654,10 @@ minetest.register_node("default:dirt_with_grass", {
 	is_ground_content = true,
 	groups = {crumbly=3},
 	drop = 'default:dirt',
+	sounds = {
+		--footstep = "default_grass_footstep",
+		footstep = {name="default_grass_footstep", gain=0.5},
+	},
 })
 
 minetest.register_node("default:dirt_with_grass_footsteps", {
diff --git a/src/camera.cpp b/src/camera.cpp
index 8dad8dc63..fada47608 100644
--- a/src/camera.cpp
+++ b/src/camera.cpp
@@ -32,6 +32,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "noise.h" // easeCurve
 #include "gamedef.h"
 #include "sound.h"
+#include "event.h"
 
 Camera::Camera(scene::ISceneManager* smgr, MapDrawControl& draw_control,
 		IGameDef *gamedef):
@@ -177,8 +178,10 @@ void Camera::step(f32 dtime)
 			bool step = (was == 0 ||
 					(was < 0.5f && m_view_bobbing_anim >= 0.5f) ||
 					(was > 0.5f && m_view_bobbing_anim <= 0.5f));
-			if(step)
-				m_gamedef->sound()->playSound("default_grass_walk", false, 1.0);
+			if(step){
+				MtEvent *e = new SimpleTriggerEvent("ViewBobbingStep");
+				m_gamedef->event()->put(e);
+			}
 		}
 	}
 
@@ -190,7 +193,8 @@ void Camera::step(f32 dtime)
 		{
 			m_digging_anim = 0;
 			m_digging_button = -1;
-			m_gamedef->sound()->playSound("dig", false, 1.0);
+			MtEvent *e = new SimpleTriggerEvent("CameraDig");
+			m_gamedef->event()->put(e);
 		}
 	}
 }
diff --git a/src/client.cpp b/src/client.cpp
index cb6d2075e..d8fb4eb77 100644
--- a/src/client.cpp
+++ b/src/client.cpp
@@ -226,12 +226,14 @@ Client::Client(
 		IWritableTextureSource *tsrc,
 		IWritableItemDefManager *itemdef,
 		IWritableNodeDefManager *nodedef,
-		ISoundManager *sound
+		ISoundManager *sound,
+		MtEventManager *event
 ):
 	m_tsrc(tsrc),
 	m_itemdef(itemdef),
 	m_nodedef(nodedef),
 	m_sound(sound),
+	m_event(event),
 	m_mesh_update_thread(this),
 	m_env(
 		new ClientMap(this, this, control,
@@ -2330,4 +2332,8 @@ ISoundManager* Client::getSoundManager()
 {
 	return m_sound;
 }
+MtEventManager* Client::getEventManager()
+{
+	return m_event;
+}
 
diff --git a/src/client.h b/src/client.h
index 2a1681e92..13b36106c 100644
--- a/src/client.h
+++ b/src/client.h
@@ -44,6 +44,7 @@ class IWritableNodeDefManager;
 //class IWritableCraftDefManager;
 class ClientEnvironment;
 struct MapDrawControl;
+class MtEventManager;
 
 class ClientNotReadyException : public BaseException
 {
@@ -175,7 +176,8 @@ public:
 			IWritableTextureSource *tsrc,
 			IWritableItemDefManager *itemdef,
 			IWritableNodeDefManager *nodedef,
-			ISoundManager *sound
+			ISoundManager *sound,
+			MtEventManager *event
 	);
 	
 	~Client();
@@ -308,6 +310,7 @@ public:
 	virtual ITextureSource* getTextureSource();
 	virtual u16 allocateUnknownNodeId(const std::string &name);
 	virtual ISoundManager* getSoundManager();
+	virtual MtEventManager* getEventManager();
 
 private:
 	
@@ -335,6 +338,8 @@ private:
 	IWritableItemDefManager *m_itemdef;
 	IWritableNodeDefManager *m_nodedef;
 	ISoundManager *m_sound;
+	MtEventManager *m_event;
+
 	MeshUpdateThread m_mesh_update_thread;
 	ClientEnvironment m_env;
 	con::Connection m_con;
diff --git a/src/event.h b/src/event.h
new file mode 100644
index 000000000..032cb2381
--- /dev/null
+++ b/src/event.h
@@ -0,0 +1,72 @@
+/*
+Minetest-c55
+Copyright (C) 2012 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#ifndef EVENT_HEADER
+#define EVENT_HEADER
+
+class MtEvent
+{
+public:
+	virtual ~MtEvent(){};
+	//virtual MtEvent* clone(){ return new IEvent; }
+	virtual const char* getType() const = 0;
+
+	MtEvent* checkIs(const std::string &type)
+	{
+		if(type == getType())
+			return this;
+		return NULL;
+	}
+};
+
+// An event with no parameters and customizable name
+class SimpleTriggerEvent: public MtEvent
+{
+	const char *type;
+public:
+	SimpleTriggerEvent(const char *type):
+		type(type)
+	{}
+	const char* getType() const
+	{return type;}
+};
+
+class MtEventReceiver
+{
+public:
+	virtual ~MtEventReceiver(){};
+	virtual void onEvent(MtEvent *e) = 0;
+};
+
+typedef void (*event_receive_func)(MtEvent *e, void *data);
+
+class MtEventManager
+{
+public:
+	virtual ~MtEventManager(){};
+	virtual void put(MtEvent *e) = 0;
+	virtual void reg(const char *type, event_receive_func f, void *data) = 0;
+	// If data==NULL, every occurence of f is deregistered.
+	virtual void dereg(const char *type, event_receive_func f, void *data) = 0;
+	virtual void reg(MtEventReceiver *r, const char *type) = 0;
+	virtual void dereg(MtEventReceiver *r, const char *type) = 0;
+};
+
+#endif
+
diff --git a/src/event_manager.h b/src/event_manager.h
new file mode 100644
index 000000000..b33d5a295
--- /dev/null
+++ b/src/event_manager.h
@@ -0,0 +1,115 @@
+/*
+Minetest-c55
+Copyright (C) 2012 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#ifndef EVENT_MANAGER_HEADER
+#define EVENT_MANAGER_HEADER
+
+#include "event.h"
+#include <list>
+#include <map>
+
+class EventManager: public MtEventManager
+{
+	static void receiverReceive(MtEvent *e, void *data)
+	{
+		MtEventReceiver *r = (MtEventReceiver*)data;
+		r->onEvent(e);
+	}
+	struct FuncSpec{
+		event_receive_func f;
+		void *d;
+		FuncSpec(event_receive_func f, void *d):
+			f(f), d(d)
+		{}
+	};
+	struct Dest{
+		std::list<FuncSpec> funcs;
+	};
+	std::map<std::string, Dest> m_dest;
+
+public:
+	~EventManager()
+	{
+	}
+	void put(MtEvent *e)
+	{
+		std::map<std::string, Dest>::iterator i = m_dest.find(e->getType());
+		if(i != m_dest.end()){
+			std::list<FuncSpec> &funcs = i->second.funcs;
+			for(std::list<FuncSpec>::iterator i = funcs.begin();
+					i != funcs.end(); i++){
+				(*(i->f))(e, i->d);
+			}
+		}
+		delete e;
+	}
+	void reg(const char *type, event_receive_func f, void *data)
+	{
+		std::map<std::string, Dest>::iterator i = m_dest.find(type);
+		if(i != m_dest.end()){
+			i->second.funcs.push_back(FuncSpec(f, data));
+		} else{
+			std::list<FuncSpec> funcs;
+			Dest dest;
+			dest.funcs.push_back(FuncSpec(f, data));
+			m_dest[type] = dest;
+		}
+	}
+	void dereg(const char *type, event_receive_func f, void *data)
+	{
+		if(type != NULL){
+			std::map<std::string, Dest>::iterator i = m_dest.find(type);
+			if(i != m_dest.end()){
+				std::list<FuncSpec> &funcs = i->second.funcs;
+				std::list<FuncSpec>::iterator i = funcs.begin();
+				while(i != funcs.end()){
+					bool remove = (i->f == f && (!data || i->d == data));
+					if(remove)
+						funcs.erase(i++);
+					else
+						i++;
+				}
+			}
+		} else{
+			for(std::map<std::string, Dest>::iterator
+					i = m_dest.begin(); i != m_dest.end(); i++){
+				std::list<FuncSpec> &funcs = i->second.funcs;
+				std::list<FuncSpec>::iterator i = funcs.begin();
+				while(i != funcs.end()){
+					bool remove = (i->f == f && (!data || i->d == data));
+					if(remove)
+						funcs.erase(i++);
+					else
+						i++;
+				}
+			}
+		}
+	}
+	void reg(MtEventReceiver *r, const char *type)
+	{
+		reg(type, EventManager::receiverReceive, r);
+	}
+	void dereg(MtEventReceiver *r, const char *type)
+	{
+		dereg(type, EventManager::receiverReceive, r);
+	}
+};
+
+#endif
+
diff --git a/src/game.cpp b/src/game.cpp
index 1b24df59b..4c9442c00 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -59,6 +59,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #if USE_AUDIO
 	#include "sound_openal.h"
 #endif
+#include "event_manager.h"
 #include <list>
 
 /*
@@ -779,6 +780,58 @@ public:
 	}
 };
 
+class SoundMaker
+{
+public:
+	ISoundManager *m_sound;
+
+	SimpleSoundSpec m_player_step_sound;
+	float m_player_step_timer;
+
+	SoundMaker(ISoundManager *sound):
+		m_sound(sound),
+		m_player_step_sound("default_grass_walk"),
+		m_player_step_timer(0)
+	{
+	}
+
+	void playPlayerStep()
+	{
+		if(m_player_step_timer <= 0 && m_player_step_sound.exists()){
+			m_player_step_timer = 0.03;
+			m_sound->playSound(m_player_step_sound, false);
+		}
+	}
+
+	static void viewBobbingStep(MtEvent *e, void *data)
+	{
+		SoundMaker *sm = (SoundMaker*)data;
+		sm->playPlayerStep();
+	}
+
+	static void playerRegainGround(MtEvent *e, void *data)
+	{
+		SoundMaker *sm = (SoundMaker*)data;
+		sm->playPlayerStep();
+	}
+
+	static void playerJump(MtEvent *e, void *data)
+	{
+	}
+
+	void registerReceiver(MtEventManager *mgr)
+	{
+		mgr->reg("ViewBobbingStep", SoundMaker::viewBobbingStep, this);
+		mgr->reg("PlayerRegainGround", SoundMaker::playerRegainGround, this);
+		mgr->reg("PlayerJump", SoundMaker::playerJump, this);
+	}
+
+	void step(float dtime)
+	{
+		m_player_step_timer -= dtime;
+	}
+};
+
 void the_game(
 	bool &kill,
 	bool random_input,
@@ -841,10 +894,19 @@ void the_game(
 		sound = &dummySoundManager;
 		sound_is_dummy = true;
 	}
+
+	// Event manager
+	EventManager eventmgr;
+
+	// Sound maker
+	SoundMaker soundmaker(sound);
+	soundmaker.registerReceiver(&eventmgr);
 	
 	// Test sounds
-	sound->loadSound("default_grass_walk", porting::path_share + DIR_DELIM
+	sound->loadSound("default_grass_footstep", porting::path_share + DIR_DELIM
 			+ "sounds" + DIR_DELIM + "default_grass_walk3_mono.ogg");
+	sound->loadSound("default_grass_footstep", porting::path_share + DIR_DELIM
+			+ "sounds" + DIR_DELIM + "default_grass_walk4_mono.ogg");
 	//sound->playSound("default_grass_walk", false, 1.0);
 	//sound->playSoundAt("default_grass_walk", true, 1.0, v3f(0,10,0)*BS);
 
@@ -879,7 +941,7 @@ void the_game(
 	MapDrawControl draw_control;
 
 	Client client(device, playername.c_str(), password, draw_control,
-			tsrc, itemdef, nodedef, sound);
+			tsrc, itemdef, nodedef, sound, &eventmgr);
 	
 	// Client acts as our GameDef
 	IGameDef *gamedef = &client;
@@ -1257,7 +1319,7 @@ void the_game(
 		if(object_hit_delay_timer >= 0)
 			object_hit_delay_timer -= dtime;
 		time_from_last_punch += dtime;
-
+		
 		g_profiler->add("Elapsed time", dtime);
 		g_profiler->avg("FPS", 1./dtime);
 
@@ -1955,6 +2017,17 @@ void the_game(
 				camera.getCameraNode()->getUpVector());
 
 		/*
+			Update sound maker
+		*/
+		{
+			soundmaker.step(dtime);
+			
+			ClientMap &map = client.getEnv().getClientMap();
+			MapNode n = map.getNodeNoEx(player->getStandingNodePos());
+			soundmaker.m_player_step_sound = nodedef->get(n).sound_footstep;
+		}
+
+		/*
 			Calculate what block is the crosshair pointing to
 		*/
 		
diff --git a/src/gamedef.h b/src/gamedef.h
index 91bcc0e65..3b5ad5cae 100644
--- a/src/gamedef.h
+++ b/src/gamedef.h
@@ -28,6 +28,7 @@ class INodeDefManager;
 class ICraftDefManager;
 class ITextureSource;
 class ISoundManager;
+class MtEventManager;
 
 /*
 	An interface for fetching game-global definitions like tool and
@@ -47,17 +48,19 @@ public:
 	// pointers in other threads than main thread will make things explode.
 	virtual ITextureSource* getTextureSource()=0;
 	
-	virtual ISoundManager* getSoundManager()=0;
-	
 	// Used for keeping track of names/ids of unknown nodes
 	virtual u16 allocateUnknownNodeId(const std::string &name)=0;
 
+	virtual ISoundManager* getSoundManager()=0;
+	virtual MtEventManager* getEventManager()=0;
+	
 	// Shorthands
 	IItemDefManager* idef(){return getItemDefManager();}
 	INodeDefManager* ndef(){return getNodeDefManager();}
 	ICraftDefManager* cdef(){return getCraftDefManager();}
 	ITextureSource* tsrc(){return getTextureSource();}
 	ISoundManager* sound(){return getSoundManager();}
+	MtEventManager* event(){return getEventManager();}
 };
 
 #endif
diff --git a/src/nodedef.cpp b/src/nodedef.cpp
index f1946830f..2a21136bf 100644
--- a/src/nodedef.cpp
+++ b/src/nodedef.cpp
@@ -79,6 +79,22 @@ void MaterialSpec::deSerialize(std::istream &is)
 }
 
 /*
+	SimpleSoundSpec serialization
+*/
+
+static void serializeSimpleSoundSpec(const SimpleSoundSpec &ss,
+		std::ostream &os)
+{
+	os<<serializeString(ss.name);
+	writeF1000(os, ss.gain);
+}
+static void deSerializeSimpleSoundSpec(SimpleSoundSpec &ss, std::istream &is)
+{
+	ss.name = deSerializeString(is);
+	ss.gain = readF1000(is);
+}
+
+/*
 	ContentFeatures
 */
 
@@ -139,6 +155,7 @@ void ContentFeatures::reset()
 	selection_box = NodeBox();
 	legacy_facedir_simple = false;
 	legacy_wallmounted = false;
+	sound_footstep = SimpleSoundSpec();
 }
 
 void ContentFeatures::serialize(std::ostream &os)
@@ -185,6 +202,7 @@ void ContentFeatures::serialize(std::ostream &os)
 	selection_box.serialize(os);
 	writeU8(os, legacy_facedir_simple);
 	writeU8(os, legacy_wallmounted);
+	serializeSimpleSoundSpec(sound_footstep, os);
 }
 
 void ContentFeatures::deSerialize(std::istream &is)
@@ -236,6 +254,9 @@ void ContentFeatures::deSerialize(std::istream &is)
 	selection_box.deSerialize(is);
 	legacy_facedir_simple = readU8(is);
 	legacy_wallmounted = readU8(is);
+	try{
+		deSerializeSimpleSoundSpec(sound_footstep, is);
+	}catch(SerializationError &e) {};
 }
 
 /*
diff --git a/src/nodedef.h b/src/nodedef.h
index 2842b81e7..3a0d0675f 100644
--- a/src/nodedef.h
+++ b/src/nodedef.h
@@ -20,7 +20,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #ifndef NODEDEF_HEADER
 #define NODEDEF_HEADER
 
-#include "common_irrlicht.h"
+#include "irrlichttypes.h"
 #include <string>
 #include <iostream>
 #include <map>
@@ -29,6 +29,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "tile.h"
 #endif
 #include "itemgroup.h"
+#include "sound.h" // SimpleSoundSpec
 class IItemDefManager;
 class ITextureSource;
 class IGameDef;
@@ -200,6 +201,9 @@ struct ContentFeatures
 	// Set to true if wall_mounted used to be set to true
 	bool legacy_wallmounted;
 
+	// Sound properties
+	SimpleSoundSpec sound_footstep;
+
 	/*
 		Methods
 	*/
diff --git a/src/player.cpp b/src/player.cpp
index 48d2c2907..0d4a1cb69 100644
--- a/src/player.cpp
+++ b/src/player.cpp
@@ -31,6 +31,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "collision.h"
 #include "environment.h"
 #include "gamedef.h"
+#include "event.h"
 
 Player::Player(IGameDef *gamedef):
 	touching_ground(false),
@@ -367,6 +368,7 @@ void LocalPlayer::move(f32 dtime, Map &map, f32 pos_max_d,
 
 		Player is allowed to jump when this is true.
 	*/
+	bool touching_ground_was = touching_ground;
 	touching_ground = false;
 
 	/*std::cout<<"Checking collisions for ("
@@ -608,6 +610,11 @@ void LocalPlayer::move(f32 dtime, Map &map, f32 pos_max_d,
 			collision_info->push_back(info);
 		}
 	}
+
+	if(!touching_ground_was && touching_ground){
+		MtEvent *e = new SimpleTriggerEvent("PlayerRegainGround");
+		m_gamedef->event()->put(e);
+	}
 }
 
 void LocalPlayer::move(f32 dtime, Map &map, f32 pos_max_d)
@@ -723,6 +730,9 @@ void LocalPlayer::applyControl(float dtime)
 			{
 				speed.Y = 6.5*BS;
 				setSpeed(speed);
+				
+				MtEvent *e = new SimpleTriggerEvent("PlayerJump");
+				m_gamedef->event()->put(e);
 			}
 		}
 		// Use the oscillating value for getting out of water
diff --git a/src/scriptapi.cpp b/src/scriptapi.cpp
index 27ab2950b..79da15c49 100644
--- a/src/scriptapi.cpp
+++ b/src/scriptapi.cpp
@@ -808,6 +808,25 @@ static void push_pointed_thing(lua_State *L, const PointedThing& pointed)
 }
 
 /*
+	SimpleSoundSpec
+*/
+
+static SimpleSoundSpec read_soundspec(lua_State *L, int index)
+{
+	if(index < 0)
+		index = lua_gettop(L) + 1 + index;
+	SimpleSoundSpec spec;
+	if(lua_isnil(L, index)){
+	} else if(lua_istable(L, index)){
+		getstringfield(L, index, "name", spec.name);
+		getfloatfield(L, index, "gain", spec.gain);
+	} else if(lua_isstring(L, index)){
+		spec.name = lua_tostring(L, index);
+	}
+	return spec;
+}
+
+/*
 	ItemDefinition
 */
 
@@ -1038,6 +1057,15 @@ static ContentFeatures read_content_features(lua_State *L, int index)
 	getboolfield(L, index, "legacy_facedir_simple", f.legacy_facedir_simple);
 	// Set to true if wall_mounted used to be set to true
 	getboolfield(L, index, "legacy_wallmounted", f.legacy_wallmounted);
+	
+	// Sound table
+	lua_getfield(L, index, "sounds");
+	if(lua_istable(L, -1)){
+		lua_getfield(L, -1, "footstep");
+		f.sound_footstep = read_soundspec(L, -1);
+		lua_pop(L, 1);
+	}
+	lua_pop(L, 1);
 
 	return f;
 }
diff --git a/src/server.cpp b/src/server.cpp
index d762f2688..e781f1284 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -50,6 +50,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "tool.h"
 #include "utility_string.h"
 #include "sound.h" // dummySoundManager
+#include "event_manager.h"
 
 #define PP(x) "("<<(x).X<<","<<(x).Y<<","<<(x).Z<<")"
 
@@ -853,6 +854,7 @@ Server::Server(
 	m_itemdef(createItemDefManager()),
 	m_nodedef(createNodeDefManager()),
 	m_craftdef(createCraftDefManager()),
+	m_event(new EventManager()),
 	m_thread(this),
 	m_emergethread(this),
 	m_time_of_day_send_timer(0),
@@ -1064,10 +1066,10 @@ Server::~Server()
 			delete i.getNode()->getValue();
 		}
 	}
-
-	// Delete Environment
+	
+	// Delete things in the reverse order of creation
 	delete m_env;
-
+	delete m_event;
 	delete m_itemdef;
 	delete m_nodedef;
 	delete m_craftdef;
@@ -4275,6 +4277,10 @@ ISoundManager* Server::getSoundManager()
 {
 	return &dummySoundManager;
 }
+MtEventManager* Server::getEventManager()
+{
+	return m_event;
+}
 
 IWritableItemDefManager* Server::getWritableItemDefManager()
 {
diff --git a/src/server.h b/src/server.h
index cdedd06d8..3baeb433d 100644
--- a/src/server.h
+++ b/src/server.h
@@ -40,6 +40,7 @@ typedef struct lua_State lua_State;
 class IWritableItemDefManager;
 class IWritableNodeDefManager;
 class IWritableCraftDefManager;
+class EventManager;
 
 class ServerError : public std::exception
 {
@@ -514,6 +515,7 @@ public:
 	virtual ITextureSource* getTextureSource();
 	virtual u16 allocateUnknownNodeId(const std::string &name);
 	virtual ISoundManager* getSoundManager();
+	virtual MtEventManager* getEventManager();
 	
 	IWritableItemDefManager* getWritableItemDefManager();
 	IWritableNodeDefManager* getWritableNodeDefManager();
@@ -684,6 +686,9 @@ private:
 	// Craft definition manager
 	IWritableCraftDefManager *m_craftdef;
 	
+	// Event manager
+	EventManager *m_event;
+	
 	// Mods
 	core::list<ModSpec> m_mods;
 	
diff --git a/src/sound.h b/src/sound.h
index 72764345e..6363d614e 100644
--- a/src/sound.h
+++ b/src/sound.h
@@ -33,6 +33,18 @@ public:
 			std::set<std::vector<char> > &dst_datas) = 0;
 };
 
+struct SimpleSoundSpec
+{
+	std::string name;
+	float gain;
+	SimpleSoundSpec(std::string name="", float gain=1.0):
+		name(name),
+		gain(gain)
+	{}
+	bool exists() {return name != "";}
+	// Serialization intentionally left out
+};
+
 class ISoundManager
 {
 public:
@@ -47,6 +59,7 @@ public:
 			const std::vector<char> &filedata) = 0;
 
 	virtual void updateListener(v3f pos, v3f vel, v3f at, v3f up) = 0;
+
 	// playSound functions return -1 on failure, otherwise a handle to the
 	// sound
 	virtual int playSound(const std::string &name, bool loop,
@@ -54,6 +67,11 @@ public:
 	virtual int playSoundAt(const std::string &name, bool loop,
 			float volume, v3f pos) = 0;
 	virtual void stopSound(int sound) = 0;
+
+	int playSound(const SimpleSoundSpec &spec, bool loop)
+		{ return playSound(spec.name, loop, spec.gain); }
+	int playSoundAt(const SimpleSoundSpec &spec, bool loop, v3f pos)
+		{ return playSoundAt(spec.name, loop, spec.gain, pos); }
 };
 
 class DummySoundManager: public ISoundManager