From 75c6db097b990e58b4b2585580a89561c838d923 Mon Sep 17 00:00:00 2001
From: Stijn Buys <ingar@osirion.org>
Date: Tue, 26 Oct 2010 21:08:12 +0000
Subject: updated network protocol version to 20, implemented invemtory
 depletion, unified depletion with keepalive

---
 src/core/application.cc   |   8 ++--
 src/core/cvar.cc          |   3 +-
 src/core/cvar.h           |   4 +-
 src/core/entity.cc        |  30 ++++---------
 src/core/entity.h         |  85 ++++++++++++++++++------------------
 src/core/gameserver.cc    | 107 ++++++++++++++++++++++++++++++----------------
 src/core/item.cc          |   8 +++-
 src/core/item.h           |  27 +++++++++++-
 src/core/net.h            |   4 +-
 src/game/base/cargopod.cc |   7 ++-
 src/game/base/cargopod.h  |   2 +
 src/game/base/game.cc     |  12 +++---
 src/game/base/game.h      |  10 ++---
 src/game/base/station.cc  |  24 +++++++++++
 src/game/base/station.h   |   2 +
 15 files changed, 208 insertions(+), 125 deletions(-)

(limited to 'src')

diff --git a/src/core/application.cc b/src/core/application.cc
index 1d7ded2..f21dcad 100644
--- a/src/core/application.cc
+++ b/src/core/application.cc
@@ -110,9 +110,6 @@ void Application::init(int count, char **arguments)
 	Cvar::sv_private = Cvar::get("sv_private", "0");
 	Cvar::sv_private->set_info("[bool] enable or disable network server for a client");
 
-	Cvar::cl_prediction = Cvar::get("cl_prediction", "0", Cvar::Archive);
-	Cvar::cl_prediction->set_info("[bool] enable or disable client prediction");
-
 	// load configuration
 	load_config();
 	load_autoexec();
@@ -133,10 +130,13 @@ void Application::init(int count, char **arguments)
 
 	Cvar::sv_password = Cvar::get("sv_password", "", Cvar::Archive);
 	Cvar::sv_password->set_info("[string] server rcon password");
+	
+	Cvar::sv_keepalive = Cvar::get("sv_keepalive", "120", core::Cvar::Archive);
+	Cvar::sv_keepalive->set_info("[int] number of seconds to keep dynamic objects alive");
 
 	// network settings
 	Cvar::net_host = Cvar::get("net_host", "0.0.0.0", Cvar::Archive);
-	Cvar::net_host->set_info("[ip] IP address the network server binds to");
+	Cvar::net_host->set_info("[address] IP address the network server binds to");
 
 	Cvar::net_port = Cvar::get("net_port", "8042", Cvar::Archive);
 	Cvar::net_port->set_info("[int] default network port");
diff --git a/src/core/cvar.cc b/src/core/cvar.cc
index a47b72e..bbdf395 100644
--- a/src/core/cvar.cc
+++ b/src/core/cvar.cc
@@ -25,8 +25,7 @@ Cvar				*Cvar::sv_name = 0;
 Cvar				*Cvar::sv_description = 0;
 Cvar				*Cvar::sv_password = 0;
 Cvar				*Cvar::sv_arraysize = 0;
-
-Cvar				*Cvar::cl_prediction = 0;
+Cvar				*Cvar::sv_keepalive = 0;
 
 Cvar				*Cvar::net_host = 0;
 Cvar				*Cvar::net_port = 0;
diff --git a/src/core/cvar.h b/src/core/cvar.h
index 21491fd..2487adc 100644
--- a/src/core/cvar.h
+++ b/src/core/cvar.h
@@ -156,10 +156,10 @@ public:
 	static Cvar		*sv_description; // server description
 	static Cvar		*sv_password;	// server rcon password
 	static Cvar 		*sv_arraysize;	// vertex array size in MegaBytes
-
+	static Cvar		*sv_keepalive;	// entity keepalive timeout
+	
 	static Cvar		*con_ansi;	// console ANSI colors
 
-	static Cvar		*cl_prediction;	// client prediction
 
 	static Cvar		*net_host;	// network server ip (default binds to all interfaces)
 	static Cvar		*net_port;	// network port
diff --git a/src/core/entity.cc b/src/core/entity.cc
index c99c186..4f13efa 100644
--- a/src/core/entity.cc
+++ b/src/core/entity.cc
@@ -160,6 +160,7 @@ Entity::Entity() :
 	entity_created = true;
 	entity_destroyed = false;
 	entity_dirty = false;
+	entity_keepalive = 0;
 
 	entity_zone = 0;
 	entity_oldzone = 0;
@@ -182,6 +183,7 @@ Entity::Entity(std::istream & is)
 	entity_zone = 0;
 	entity_oldzone = 0;
 	entity_visible = true;
+	entity_keepalive = 0;
 
 	entity_model = 0;
 
@@ -471,6 +473,10 @@ void Entity::frame(float seconds)
 {
 }
 
+void Entity::upkeep(const unsigned long timestamp)
+{
+}
+
 void Entity::add_menu(MenuDescription *menu)
 {
 	entity_menus.push_back(menu);
@@ -544,16 +550,12 @@ EntityDynamic::EntityDynamic() : Entity()
 {
 	entity_state = Normal;
 	entity_timer = 0;
-	entity_keepalive_time = 0.0f;
-	entity_keepalive_timeout = 0.0f;
 }
 
 EntityDynamic::EntityDynamic(std::istream & is) : Entity(is)
 {
 	entity_state = Normal;
 	entity_timer = 0;
-	entity_keepalive_time = 0.0f;
-	entity_keepalive_timeout = 0.0f;
 }
 
 EntityDynamic::~EntityDynamic()
@@ -568,16 +570,6 @@ void EntityDynamic::set_state(int state)
 	}
 }
 
-void EntityDynamic::set_keepalive_time(float time)
-{
-	entity_keepalive_time = time;
-}
-	
-void EntityDynamic::set_keepalive_timeout(float timeout)
-{
-	entity_keepalive_timeout = timeout;
-}
-
 void EntityDynamic::reset()
 {
 	Entity::reset();
@@ -596,13 +588,7 @@ void EntityDynamic::frame(float seconds)
 	if (entity_state == Docked) {
 		return;
 	}
-	
-	if (flag_is_set(KeepAlive)) {
-		if ((keepalive_time() > 0.0f) && (keepalive_time() < server()->time())) {
-			die();
-		}
-	}
-	
+
 	// transfer bullet state to entity state
 	if (entity_body) {
 		// this makes sure an update is sent if speed goes to 0 in the next step
@@ -822,6 +808,7 @@ void EntityControlable::serialize_client_update(std::ostream & os) const
 	os << target_thrust << " ";
 	os << target_roll << " ";
 	os << target_strafe << " ";
+	os << target_vstrafe << " ";
 	os << target_afterburner << " ";
 }
 
@@ -833,6 +820,7 @@ void EntityControlable::receive_client_update(std::istream &is)
 	is >> target_thrust;
 	is >> target_roll;
 	is >> target_strafe;
+	is >> target_vstrafe;
 	is >> target_afterburner;
 }
 
diff --git a/src/core/entity.h b/src/core/entity.h
index 8dd5644..954b261 100644
--- a/src/core/entity.h
+++ b/src/core/entity.h
@@ -216,6 +216,11 @@ public:
 		return entity_destroyed;
 	}
 
+	/// time when the entity was last alive
+	inline unsigned long keepalive() const {
+		return entity_keepalive;
+	}
+	
 	/// list inventory, if available, to console
 	void list_inventory() const;
 
@@ -254,6 +259,15 @@ public:
 	 */
 	virtual void frame(float seconds);
 
+	/**
+	 * @brief runs one upkeep frame for the entity
+	 * The upkeep frame will be executed by the engine if the entity has the KeepAlive flag set
+	 * and the keepalive timeout has been elapsed.
+	 * The default implementation does nothing
+	 * @param timestamp game timestamp for the current upkeep frame
+	 */
+	virtual void upkeep(const unsigned long timestamp);
+	
 	/**
 	 * @brief set the zone the entity is currently in
 	 * this fuction removes the entity from its previous zone
@@ -282,18 +296,42 @@ public:
 		entity_radius = radius;
 	}
 	
-	/* ---- actors ---------------------------------------------------- */
+		
+	/// set location
+	inline void set_location(const math::Vector3f &location) {
+		entity_location.assign(location);
+	}
+	
+	/// set location
+	inline void set_axis(const math::Axis &axis) {
+		entity_axis.assign(axis);
+	}
 
-	/// set flags
+	/// set flag
 	inline void set_flag(Flags flag) {
 		entity_flags |= flag;
 	}
 
-	/// unset flags
+	/// unset flag
 	inline void unset_flag(Flags flag) {
 		entity_flags &= ~flag;
 	}
 
+	/**
+	 * @brief add an inventory to this entity
+	 * Entity takes ownership over the inventory pointer
+	 */
+	 void set_inventory(Inventory *inventory);
+	 
+	 void set_info(Info *info);
+	 
+	/// set the timestamp when the entity was last alive
+	void set_keepalive(unsigned long timestamp) {
+		entity_keepalive = timestamp;
+	}
+
+	/* ---- actors ---------------------------------------------------- */
+
 	/**
 	 * @brief reset the physics state
 	 */
@@ -307,16 +345,6 @@ public:
 
 	/// clear all update flags
 	virtual void clear_updates();
-	
-	/// set location
-	inline void set_location(const math::Vector3f &location) {
-		entity_location.assign(location);
-	}
-	
-	/// set location
-	inline void set_axis(const math::Axis &axis) {
-		entity_axis.assign(axis);
-	}
 
 	/**
 	 * @brief mutable reference to the location
@@ -345,15 +373,7 @@ public:
 	inline math::Color& get_color_second() {
 		return entity_color_second;
 	}
-
-	/**
-	 * @brief add an inventory to this entity
-	 * Entity takes ownership over the inventory pointer
-	 */
-	 void set_inventory(Inventory *inventory);
-	 
-	 void set_info(Info *info);
-	 
+ 
 	/* ---- deserializers -------------------------------------- */
 
 	/// receive a client-to-server update from a stream
@@ -376,7 +396,6 @@ public:
 	/// serialize a server-to-client update on a stream
 	virtual void serialize_server_update(std::ostream & os) const;
 
-
 	/* ---- static --------------------------------------------- */
 
 	/// type definition for the entity registry
@@ -459,6 +478,8 @@ private:
 
 	Extension*		entity_extension[4];
 	
+	unsigned long		entity_keepalive;
+	
 	static Registry 	entity_registry;
 	static size_t		entity_nextid;
 
@@ -494,16 +515,6 @@ public:
 		return entity_timer;
 	}
 
-	/// time when the entity was last alive
-	inline const float keepalive_time() const {
-		return entity_keepalive_time;
-	}
-	
-	/// keepalive timeout
-	inline const float keepalive_timeout() const {
-		return entity_keepalive_timeout;
-	}	
-	
 	/*----- mutators -------------------------------------------------- */
 
 	/// mass of the entity
@@ -540,12 +551,6 @@ public:
 
 	/// set event state
 	virtual void set_state(int state);
-	
-	/// set the time when the entity was last alive, in game time seconds
-	void set_keepalive_time(float time);
-	
-	/// set the timeout after which the entitie is deleted, in seconds
-	void set_keepalive_timeout(float timeout);
 
 	/// runs one game frame for the entity
 	/**
@@ -560,8 +565,6 @@ public:
 	virtual void reset();
 
 protected:
-	float			entity_keepalive_time;
-	float			entity_keepalive_timeout;
 	float			entity_timer;
 	int			entity_state;
 };
diff --git a/src/core/gameserver.cc b/src/core/gameserver.cc
index 344c069..f84e228 100644
--- a/src/core/gameserver.cc
+++ b/src/core/gameserver.cc
@@ -509,19 +509,77 @@ void GameServer::frame(unsigned long timestamp)
 
 	server_previoustime = server_timestamp;
 	server_timestamp = timestamp - server_startup;
-	float elapsed = (float)(server_timestamp - server_previoustime) / 1000.0f;
+	const float elapsed = (float)(server_timestamp - server_previoustime) / 1000.0f;
+	const unsigned long keepalive_timeout = (Cvar::sv_keepalive ? 1000 * (unsigned long) Cvar::sv_keepalive->value() : (unsigned long) 0 );
 
-	// copy the previous entity state to the client state
-	/*if (!Cvar::sv_dedicated->value()) {
-		reset_clientstate();
-	}*/
-
-	// run a time frame on each entity
-	for (Entity::Registry::iterator it = Entity::registry().begin(); it != Entity::registry().end(); it++) {
-		Entity *entity = (*it).second;
+	for (Zone::Registry::iterator zit = Zone::registry().begin(); zit != Zone::registry().end(); zit++) {
+		Zone *zone= (*zit).second;
+		
+		bool keepalive_run = false;
+		math::Vector3f keepalive_maxbox;
+		math::Vector3f keepalive_minbox;
 
-		if ((entity->type() == Entity::Controlable) || (entity->type() == Entity::Dynamic)) {
-			entity->frame(elapsed);
+		// run a game frame on all dynamic and controlable entities
+		for (Zone::Content::iterator it = zone->content().begin(); it != zone->content().end(); it++) {			
+			Entity *entity = (*it);
+			
+			if (entity->type() == Entity::Dynamic) {
+				entity->frame(elapsed);
+				
+			} else if (entity->type() == Entity::Controlable) {
+				EntityControlable *controlable = static_cast<EntityControlable *>(entity);
+				controlable->frame(elapsed);
+				
+				if (controlable->owner() && (controlable->owner()->control() == controlable)) {
+					// add player controlable to keepalive bounding box
+					if (!keepalive_run) {
+						keepalive_maxbox.assign(controlable->location());
+						keepalive_minbox.assign(controlable->location());
+						keepalive_run = true;
+					} else {
+						for (size_t i = 0; i < 3; i++) {
+							if (keepalive_maxbox[i] < controlable->location()[i])
+								keepalive_maxbox[i] = controlable->location()[i];
+							if (keepalive_minbox[i] > controlable->location()[i])
+								keepalive_minbox[i] = controlable->location()[i];
+						}
+					}
+				}
+			}			
+		}
+		
+		// expand keepalive bounding box
+		for (size_t i = 0; i < 3; i++) {
+			keepalive_maxbox[i] += range::fxdistance * 0.5f;
+			keepalive_minbox[i] -= range::fxdistance * 0.5f;
+		}
+		
+		// run an upkeep frame on entities that require it
+		for (Zone::Content::iterator it = zone->content().begin(); it != zone->content().end(); it++) {
+			Entity *entity = (*it);
+			
+			// if entity is inside the keepalive bounding box, the keepalive timestamp will be set to the current game timestamp
+			if (entity->flag_is_set(Entity::KeepAlive)) {
+				if (keepalive_run) {
+					bool alive = true;
+					
+					// bounding box test
+					for (size_t i = 0; alive && (i < 3); i++) {
+						if ((entity->location()[i] > keepalive_maxbox[i]) || (entity->location()[i] < keepalive_minbox[i])) {
+							alive = false;
+						}
+					}
+					
+					if (alive) {
+						entity->set_keepalive(server_timestamp);
+					}
+				}
+				
+				// run upkeep if the keepalive timeout has elapsed
+				if (entity->keepalive() + keepalive_timeout < server_timestamp) {
+					entity->upkeep(server_timestamp);
+				}
+			}
 		}
 	}
 
@@ -543,7 +601,7 @@ void GameServer::frame(unsigned long timestamp)
 		EntityControlable *control = player->control();
 		
 		// the player is viewing an entity
-		if (view) {			
+		if (view) {
 			// the view has changed zone
 			if (view->zone() != player->zone()) {
 				if (control) {
@@ -589,31 +647,6 @@ void GameServer::frame(unsigned long timestamp)
 		server_network->frame(server_timestamp);
 	}
 	
-	const float keepalive_distance_squared = range::fxdistance * range::fxdistance;
-
-	// FIXME KeepAlive sweep has to be done in linear order, O(n^2) is extremely slow with a large number of entities
-	
-	for (Entity::Registry::const_iterator it = Entity::registry().begin(); it != Entity::registry().end(); it++) {
-		
-		// set keepalive timeout
-		if ((*it).second->type() == Entity::Controlable) {
-			const EntityControlable *controlable = static_cast<const EntityControlable *>((*it).second);
-			
-			if ( (controlable->state() != Entity::Docked) && controlable->owner() && controlable->zone() ) {
-				for (Zone::Content::iterator zit = controlable->zone()->content().begin(); zit != controlable->zone()->content().end(); zit++) {
-					
-					if ( ((*zit)->flag_is_set(Entity::KeepAlive)) && ((*zit)->type() == Entity::Dynamic) && ((*zit) != controlable) ) {
-						EntityDynamic *dynamic = static_cast<EntityDynamic *>(*zit);
-						if (math::distancesquared(controlable->location(), dynamic->location()) < keepalive_distance_squared) {
-							dynamic->set_keepalive_time(time() + dynamic->keepalive_timeout());
-						}
-					}
-				}
-			}
-			
-		}
-	}
-	
 	// remove deleted entities and mark remaining entities as updated
 	for (Entity::Registry::iterator it = Entity::registry().begin(); it != Entity::registry().end();) {
 		// remove deleted entities
diff --git a/src/core/item.cc b/src/core/item.cc
index df12885..3768afa 100644
--- a/src/core/item.cc
+++ b/src/core/item.cc
@@ -23,6 +23,7 @@ Item::Item(const Info *info)
 {
 	item_info = info;
 	item_amount = 0;
+	item_flags = 0;
 	item_price = info->price();
 	set_timestamp(game() ? game()->timestamp() : 1);
 }
@@ -31,6 +32,7 @@ Item::Item(const Item &other)
 {
 	item_info = other.info();
 	item_amount = other.amount();
+	item_flags = other.flags();
 	item_price = other.price();
 	set_timestamp(game() ? game()->timestamp() : 1);
 }
@@ -39,7 +41,8 @@ Item::~Item()
 {
 	item_info = 0;
 	item_amount = 0;
-	item_amount = 0;
+	item_flags = 0;
+	item_price = 0;
 }
 
 void Item::set_amount(const long amount)
@@ -73,13 +76,14 @@ void Item::set_timestamp(const unsigned long timestamp)
 
 void Item::serialize_server_update(std::ostream & os) const
 {
-	os << amount() << " " << price() << " ";
+	os << amount() << " " << price() << " " << flags() << " ";
 }
 
 void Item::receive_server_update(std::istream &is)
 {
 	is >> item_amount;
 	is >> item_price;
+	is >> item_flags;
 }
 
 } // namespace core
diff --git a/src/core/item.h b/src/core/item.h
index 0e9e167..ac3188d 100644
--- a/src/core/item.h
+++ b/src/core/item.h
@@ -19,6 +19,8 @@ namespace core
 class Item
 {
 public:
+	enum Flags {Tradeable = 1};
+	
 	Item(const Info *info);
 	
 	/// copy constructor
@@ -46,7 +48,17 @@ public:
 	inline const unsigned long timestamp() const {
 		return item_timestamp;
 	}
-	  
+	
+	/// item flags
+	inline const unsigned int flags() const {
+		return item_flags;
+	}
+	
+	/// returns true of a flag is set
+	inline const bool flag_is_set(const Flags flag) const {
+		return ((item_flags & (unsigned int)flag) == (unsigned int)flag);
+	}
+	
 	/* ---- mutators ----------------------------------------------- */
 
 	/**
@@ -59,7 +71,16 @@ public:
 	void dec_amount(const long amount);
 	 
 	void set_price(const long price);
-	 
+	
+	/// set flag
+	inline void set_flag(Flags flag) {
+		item_flags |= flag;
+	}
+
+	/// unset flag
+	inline void unset_flag(Flags flag) {
+		item_flags &= ~flag;
+	}
 	void set_dirty();
 	
 	/* ---- serializers -------------------------------------------- */
@@ -76,6 +97,8 @@ private:
 	long 			item_amount;
 	
 	unsigned long		item_timestamp;
+	
+	unsigned int		item_flags;
 };
 
 } // namespace core
diff --git a/src/core/net.h b/src/core/net.h
index 39dfdf6..31fc6d7 100644
--- a/src/core/net.h
+++ b/src/core/net.h
@@ -11,7 +11,7 @@ namespace core
 {
 
 /// network protocol version
-const unsigned int PROTOCOLVERSION = 19;
+const unsigned int PROTOCOLVERSION = 20;
 
 /// maximum lenght of a (compressed) network message block
 const unsigned int FRAMESIZE = 1152;
@@ -24,7 +24,7 @@ const unsigned int MAXPENDINGCONNECTIONS = 32;
 const unsigned int DEFAULTPORT = 8042;
 
 /// network timeout in seconds
-const float NETTIMEOUT = 20;
+const float NETTIMEOUT = 15;
 
 }
 
diff --git a/src/game/base/cargopod.cc b/src/game/base/cargopod.cc
index 5ea4105..7406d3a 100644
--- a/src/game/base/cargopod.cc
+++ b/src/game/base/cargopod.cc
@@ -17,7 +17,6 @@ CargoPod::CargoPod() : EntityDynamic()
 	set_label("cargopod");
 		
 	set_flag(core::Entity::KeepAlive);
-	set_keepalive_timeout(Game::g_keepalive ? Game::g_keepalive->value() : 0);
 	
 	if (Default::podmodel)
 		set_modelname(Default::podmodel->name());
@@ -35,5 +34,11 @@ CargoPod::~CargoPod()
 
 }
 
+void CargoPod::upkeep(const unsigned long timestamp)
+{
+	// cargo pods dissapear on upkeep
+	die();
+}
+
 } // namespace game
 
diff --git a/src/game/base/cargopod.h b/src/game/base/cargopod.h
index daeb9bc..7bce9a4 100644
--- a/src/game/base/cargopod.h
+++ b/src/game/base/cargopod.h
@@ -17,6 +17,8 @@ class CargoPod : public core::EntityDynamic
 public:
 	CargoPod();
 	virtual ~CargoPod();
+	
+	virtual void upkeep(const unsigned long timestamp);
 };
 
 } // namespace game
diff --git a/src/game/base/game.cc b/src/game/base/game.cc
index 7aa1081..40c7c28 100644
--- a/src/game/base/game.cc
+++ b/src/game/base/game.cc
@@ -54,7 +54,7 @@ core::Cvar *Game::g_impulsespeed = 0;
 core::Cvar *Game::g_jumppointrange = 0;
 core::Cvar *Game::g_devel = 0;
 core::Cvar *Game::g_damping = 0;
-core::Cvar *Game::g_keepalive;
+core::Cvar *Game::g_deplete = 0;
 
 core::Module *factory()
 {
@@ -905,8 +905,8 @@ Game::Game() : core::Module("Project::OSiRiON", true)
 	g_damping = core::Cvar::get("g_damping", "0.1", core::Cvar::Archive);
 	g_damping->set_info("[float] physics damping factor (0-1)");
 	
-	g_keepalive = core::Cvar::get("g_keepalive", "300", core::Cvar::Archive);
-	g_keepalive->set_info("[float] amount of time dynamic objects are kept alive, in seconds");
+	g_deplete = core::Cvar::get("g_deplete", "60", core::Cvar::Archive);
+	g_deplete->set_info("[int] number of seconds to deplete 1 unit of cargo from inventories");
 }
 
 Game::~Game()
@@ -915,7 +915,6 @@ Game::~Game()
 	g_jumppointrange = 0;
 	g_devel = 0;
 	g_damping = 0;
-	g_keepalive = 0;
 	// game functions are automaticly removed
 
 	// FIXME move cleanup sequence to core::
@@ -1025,7 +1024,7 @@ bool Game::load_zone(core::Zone *zone)
 
 	bool b;
 	long l;
-
+	
 	std::string strval;
 
 	while (zoneini.getline()) {
@@ -1307,7 +1306,7 @@ bool Game::validate_zone(core::Zone *zone)
 			JumpGate *jumpgate = static_cast<JumpGate *>(entity);
 			jumpgate->validate();
 		} else {
-			if ((entity->flags() & core::Entity::Dockable) == core::Entity::Dockable) {
+			if (entity->flag_is_set(core::Entity::Dockable)) {
 				generate_entity_menus(entity);
 			}
 		}
@@ -1351,6 +1350,7 @@ bool Game::generate_entity_menus(core::Entity *entity)
 	
 	// add trade menus	
 	if (entity->inventory()) {
+		entity->set_flag(core::Entity::KeepAlive);
 		size_t nbcargo = 0;
 		size_t nbships = 0;
 		
diff --git a/src/game/base/game.h b/src/game/base/game.h
index d879a30..dd47cef 100644
--- a/src/game/base/game.h
+++ b/src/game/base/game.h
@@ -36,7 +36,7 @@ const unsigned int station_enttype = 262;
 const unsigned int cargopod_enttype = 263;
 
 // planet docking distance
-const float planet_safe_distance = 150.0f;
+const float planet_safe_distance = 50.0f;
 
 const float jump_timer_delay = 5.0f;
 const float impulse_timer_delay = 3.0f;
@@ -85,12 +85,12 @@ public:
 	/// game variable: enable or disable development mode (cheat mode)
 	static core::Cvar *g_devel;
 	
+	/// game variable: number of seconds it takes for 1 unit of cargo to deplete from station inventories
+	static core::Cvar *g_deplete;
+	
 	/// physics variable: default damping factor of space 
-	static core::Cvar *g_damping;	
+	static core::Cvar *g_damping;
 	
-	/// game variable: amount of time dynamic objects are kept alive when there are no players
-	static core::Cvar *g_keepalive;
-
 private:
 
 	bool load_world();
diff --git a/src/game/base/station.cc b/src/game/base/station.cc
index 0d992bd..6493348 100644
--- a/src/game/base/station.cc
+++ b/src/game/base/station.cc
@@ -20,6 +20,30 @@ Station::Station() : Entity()
 
 Station::~Station()
 {
+	
+}
+
+void Station::upkeep(const unsigned long timestamp)
+{
+	if (!inventory())
+		return;
+	
+	const unsigned long deplete = (Game::g_deplete ? 1000 * (unsigned long) Game::g_deplete->value() : 0);
+	
+	if (deplete > 0) {
+		bool dirty = false;
+		for (core::Inventory::Items::iterator it = inventory()->items().begin(); it != inventory()->items().end(); it++) {
+			core::Item *item = (*it);
+			if ((item->amount() > 0) && (item->timestamp() + deplete < timestamp)) {
+				item->dec_amount(1);
+				dirty = true;
+			}
+		}
+		
+		if (dirty) {
+			inventory()->set_dirty();
+		}
+	}
 }
 
 }
diff --git a/src/game/base/station.h b/src/game/base/station.h
index 2aa8a95..5f833c4 100644
--- a/src/game/base/station.h
+++ b/src/game/base/station.h
@@ -15,6 +15,8 @@ class Station : public core::Entity
 public:
 	Station();
 	virtual ~Station();
+	
+	virtual void upkeep(const unsigned long timestamp);
 };
 
 }
-- 
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