minetest/src/environment.cpp

/*
Minetest-c55
Copyright (C) 2010 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.
*/

#include "environment.h"
#include "filesys.h"
#include "porting.h"

Environment::Environment()
{
	m_daynight_ratio = 0.5;
}

Environment::~Environment()
{
	// Deallocate players
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		delete (*i);
	}
}

void Environment::addPlayer(Player *player)
{
	DSTACK(__FUNCTION_NAME);
	/*
		Check that peer_ids are unique.
		Also check that names are unique.
		Exception: there can be multiple players with peer_id=0
	*/
	// If peer id is non-zero, it has to be unique.
	if(player->peer_id != 0)
		assert(getPlayer(player->peer_id) == NULL);
	// Name has to be unique.
	assert(getPlayer(player->getName()) == NULL);
	// Add.
	m_players.push_back(player);
}

void Environment::removePlayer(u16 peer_id)
{
	DSTACK(__FUNCTION_NAME);
re_search:
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(player->peer_id != peer_id)
			continue;
		
		delete player;
		m_players.erase(i);
		// See if there is an another one
		// (shouldn't be, but just to be sure)
		goto re_search;
	}
}

Player * Environment::getPlayer(u16 peer_id)
{
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(player->peer_id == peer_id)
			return player;
	}
	return NULL;
}

Player * Environment::getPlayer(const char *name)
{
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(strcmp(player->getName(), name) == 0)
			return player;
	}
	return NULL;
}

Player * Environment::getRandomConnectedPlayer()
{
	core::list<Player*> connected_players = getPlayers(true);
	u32 chosen_one = myrand() % connected_players.size();
	u32 j = 0;
	for(core::list<Player*>::Iterator
			i = connected_players.begin();
			i != connected_players.end(); i++)
	{
		if(j == chosen_one)
		{
			Player *player = *i;
			return player;
		}
		j++;
	}
	return NULL;
}

Player * Environment::getNearestConnectedPlayer(v3f pos)
{
	core::list<Player*> connected_players = getPlayers(true);
	f32 nearest_d = 0;
	Player *nearest_player = NULL;
	for(core::list<Player*>::Iterator
			i = connected_players.begin();
			i != connected_players.end(); i++)
	{
		Player *player = *i;
		f32 d = player->getPosition().getDistanceFrom(pos);
		if(d < nearest_d || nearest_player == NULL)
		{
			nearest_d = d;
			nearest_player = player;
		}
	}
	return nearest_player;
}

core::list<Player*> Environment::getPlayers()
{
	return m_players;
}

core::list<Player*> Environment::getPlayers(bool ignore_disconnected)
{
	core::list<Player*> newlist;
	for(core::list<Player*>::Iterator
			i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		
		if(ignore_disconnected)
		{
			// Ignore disconnected players
			if(player->peer_id == 0)
				continue;
		}

		newlist.push_back(player);
	}
	return newlist;
}

void Environment::printPlayers(std::ostream &o)
{
	o<<"Players in environment:"<<std::endl;
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		o<<"Player peer_id="<<player->peer_id<<std::endl;
	}
}

void Environment::setDayNightRatio(u32 r)
{
	m_daynight_ratio = r;
}

u32 Environment::getDayNightRatio()
{
	return m_daynight_ratio;
}

/*
	ServerEnvironment
*/

ServerEnvironment::ServerEnvironment(ServerMap *map, Server *server):
	m_map(map),
	m_server(server),
	m_random_spawn_timer(3),
	m_send_recommended_timer(0)
{
}

ServerEnvironment::~ServerEnvironment()
{
	// Drop/delete map
	m_map->drop();
}

void ServerEnvironment::serializePlayers(const std::string &savedir)
{
	std::string players_path = savedir + "/players";
	fs::CreateDir(players_path);

	core::map<Player*, bool> saved_players;

	std::vector<fs::DirListNode> player_files = fs::GetDirListing(players_path);
	for(u32 i=0; i<player_files.size(); i++)
	{
		if(player_files[i].dir)
			continue;
		
		// Full path to this file
		std::string path = players_path + "/" + player_files[i].name;

		//dstream<<"Checking player file "<<path<<std::endl;

		// Load player to see what is its name
		ServerRemotePlayer testplayer;
		{
			// Open file and deserialize
			std::ifstream is(path.c_str(), std::ios_base::binary);
			if(is.good() == false)
			{
				dstream<<"Failed to read "<<path<<std::endl;
				continue;
			}
			testplayer.deSerialize(is);
		}

		//dstream<<"Loaded test player with name "<<testplayer.getName()<<std::endl;
		
		// Search for the player
		std::string playername = testplayer.getName();
		Player *player = getPlayer(playername.c_str());
		if(player == NULL)
		{
			dstream<<"Didn't find matching player, ignoring file "<<path<<std::endl;
			continue;
		}

		//dstream<<"Found matching player, overwriting."<<std::endl;

		// OK, found. Save player there.
		{
			// Open file and serialize
			std::ofstream os(path.c_str(), std::ios_base::binary);
			if(os.good() == false)
			{
				dstream<<"Failed to overwrite "<<path<<std::endl;
				continue;
			}
			player->serialize(os);
			saved_players.insert(player, true);
		}
	}

	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(saved_players.find(player) != NULL)
		{
			/*dstream<<"Player "<<player->getName()
					<<" was already saved."<<std::endl;*/
			continue;
		}
		std::string playername = player->getName();
		// Don't save unnamed player
		if(playername == "")
		{
			//dstream<<"Not saving unnamed player."<<std::endl;
			continue;
		}
		/*
			Find a sane filename
		*/
		if(string_allowed(playername, PLAYERNAME_ALLOWED_CHARS) == false)
			playername = "player";
		std::string path = players_path + "/" + playername;
		bool found = false;
		for(u32 i=0; i<1000; i++)
		{
			if(fs::PathExists(path) == false)
			{
				found = true;
				break;
			}
			path = players_path + "/" + playername + itos(i);
		}
		if(found == false)
		{
			dstream<<"WARNING: Didn't find free file for player"<<std::endl;
			continue;
		}

		{
			/*dstream<<"Saving player "<<player->getName()<<" to "
					<<path<<std::endl;*/
			// Open file and serialize
			std::ofstream os(path.c_str(), std::ios_base::binary);
			if(os.good() == false)
			{
				dstream<<"WARNING: Failed to overwrite "<<path<<std::endl;
				continue;
			}
			player->serialize(os);
			saved_players.insert(player, true);
		}
	}

	//dstream<<"Saved "<<saved_players.size()<<" players."<<std::endl;
}

void ServerEnvironment::deSerializePlayers(const std::string &savedir)
{
	std::string players_path = savedir + "/players";

	core::map<Player*, bool> saved_players;

	std::vector<fs::DirListNode> player_files = fs::GetDirListing(players_path);
	for(u32 i=0; i<player_files.size(); i++)
	{
		if(player_files[i].dir)
			continue;
		
		// Full path to this file
		std::string path = players_path + "/" + player_files[i].name;

		dstream<<"Checking player file "<<path<<std::endl;

		// Load player to see what is its name
		ServerRemotePlayer testplayer;
		{
			// Open file and deserialize
			std::ifstream is(path.c_str(), std::ios_base::binary);
			if(is.good() == false)
			{
				dstream<<"Failed to read "<<path<<std::endl;
				continue;
			}
			testplayer.deSerialize(is);
		}

		dstream<<"Loaded test player with name "<<testplayer.getName()<<std::endl;
		
		// Search for the player
		std::string playername = testplayer.getName();
		Player *player = getPlayer(playername.c_str());
		bool newplayer = false;
		if(player == NULL)
		{
			dstream<<"Is a new player"<<std::endl;
			player = new ServerRemotePlayer();
			newplayer = true;
		}

		// Load player
		{
			dstream<<"Reading player "<<testplayer.getName()<<" from "
					<<path<<std::endl;
			// Open file and deserialize
			std::ifstream is(path.c_str(), std::ios_base::binary);
			if(is.good() == false)
			{
				dstream<<"Failed to read "<<path<<std::endl;
				continue;
			}
			player->deSerialize(is);
		}

		if(newplayer)
			addPlayer(player);
	}
}

void ServerEnvironment::step(float dtime)
{
	DSTACK(__FUNCTION_NAME);
	
	//TimeTaker timer("ServerEnv step");

	// Get some settings
	//bool free_move = g_settings.getBool("free_move");
	bool footprints = g_settings.getBool("footprints");

	{
		//TimeTaker timer("Server m_map->timerUpdate()", g_device);
		m_map->timerUpdate(dtime);
	}

	/*
		Handle players
	*/
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		
		// Ignore disconnected players
		if(player->peer_id == 0)
			continue;

		v3f playerpos = player->getPosition();
		
		// Move
		player->move(dtime, *m_map, 100*BS);
		
		/*
			Add footsteps to grass
		*/
		if(footprints)
		{
			// Get node that is at BS/4 under player
			v3s16 bottompos = floatToInt(playerpos + v3f(0,-BS/4,0), BS);
			try{
				MapNode n = m_map->getNode(bottompos);
				if(n.d == CONTENT_GRASS)
				{
					n.d = CONTENT_GRASS_FOOTSTEPS;
					m_map->setNode(bottompos, n);
				}
			}
			catch(InvalidPositionException &e)
			{
			}
		}
	}
	
	/*
		Step active objects
	*/

	bool send_recommended = false;
	m_send_recommended_timer += dtime;
	if(m_send_recommended_timer > 0.15)
	{
		m_send_recommended_timer = 0;
		send_recommended = true;
	}

	for(core::map<u16, ServerActiveObject*>::Iterator
			i = m_active_objects.getIterator();
			i.atEnd()==false; i++)
	{
		ServerActiveObject* obj = i.getNode()->getValue();
		// Step object, putting messages directly to the queue
		obj->step(dtime, m_active_object_messages, send_recommended);
	}

	if(m_object_management_interval.step(dtime, 0.5))
	{
		//TimeTaker timer("ServerEnv object management");

		/*
			Remove objects that satisfy (m_removed && m_known_by_count==0)
		*/
		{
			core::list<u16> objects_to_remove;
			for(core::map<u16, ServerActiveObject*>::Iterator
					i = m_active_objects.getIterator();
					i.atEnd()==false; i++)
			{
				u16 id = i.getNode()->getKey();
				ServerActiveObject* obj = i.getNode()->getValue();
				// This shouldn't happen but check it
				if(obj == NULL)
				{
					dstream<<"WARNING: NULL object found in ServerEnvironment"
							<<" while finding removed objects. id="<<id<<std::endl;
					// Id to be removed from m_active_objects
					objects_to_remove.push_back(id);
					continue;
				}
				// If not m_removed, don't remove.
				if(obj->m_removed == false)
					continue;
				// Delete static data from block
				if(obj->m_static_exists)
				{
					MapBlock *block = m_map->getBlockNoCreateNoEx(obj->m_static_block);
					if(block)
					{
						block->m_static_objects.remove(id);
						block->setChangedFlag();
					}
				}
				// If m_known_by_count > 0, don't actually remove.
				if(obj->m_known_by_count > 0)
					continue;
				// Delete
				delete obj;
				// Id to be removed from m_active_objects
				objects_to_remove.push_back(id);
			}
			// Remove references from m_active_objects
			for(core::list<u16>::Iterator i = objects_to_remove.begin();
					i != objects_to_remove.end(); i++)
			{
				m_active_objects.remove(*i);
			}
		}
		

		const s16 to_active_max_blocks = 3;
		const f32 to_static_max_f = (to_active_max_blocks+1)*MAP_BLOCKSIZE*BS;

		/*
			Convert stored objects from blocks near the players to active.
		*/
		for(core::list<Player*>::Iterator i = m_players.begin();
				i != m_players.end(); i++)
		{
			Player *player = *i;
			
			// Ignore disconnected players
			if(player->peer_id == 0)
				continue;

			v3f playerpos = player->getPosition();
			
			v3s16 blockpos0 = getNodeBlockPos(floatToInt(playerpos, BS));
			v3s16 bpmin = blockpos0 - v3s16(1,1,1)*to_active_max_blocks;
			v3s16 bpmax = blockpos0 + v3s16(1,1,1)*to_active_max_blocks;
			// Loop through all nearby blocks
			for(s16 x=bpmin.X; x<=bpmax.X; x++)
			for(s16 y=bpmin.Y; y<=bpmax.Y; y++)
			for(s16 z=bpmin.Z; z<=bpmax.Z; z++)
			{
				v3s16 blockpos(x,y,z);
				MapBlock *block = m_map->getBlockNoCreateNoEx(blockpos);
				if(block==NULL)
					continue;
				// Ignore if no stored objects (to not set changed flag)
				if(block->m_static_objects.m_stored.size() == 0)
					continue;
				// This will contain the leftovers of the stored list
				core::list<StaticObject> new_stored;
				// Loop through stored static objects
				for(core::list<StaticObject>::Iterator
						i = block->m_static_objects.m_stored.begin();
						i != block->m_static_objects.m_stored.end(); i++)
				{
					/*dstream<<"INFO: Server: Creating an active object from "
							<<"static data"<<std::endl;*/
					StaticObject &s_obj = *i;
					// Create an active object from the data
					ServerActiveObject *obj = ServerActiveObject::create
							(s_obj.type, this, 0, s_obj.pos, s_obj.data);
					if(obj==NULL)
					{
						// This is necessary to preserve stuff during bugs
						// and errors
						new_stored.push_back(s_obj);
						continue;
					}
					// This will also add the object to the active static list
					addActiveObject(obj);
					//u16 id = addActiveObject(obj);
				}
				// Clear stored list
				block->m_static_objects.m_stored.clear();
				// Add leftover stuff to stored list
				for(core::list<StaticObject>::Iterator
						i = new_stored.begin();
						i != new_stored.end(); i++)
				{
					StaticObject &s_obj = *i;
					block->m_static_objects.m_stored.push_back(s_obj);
				}
				block->setChangedFlag();
			}
		}

		/*
			Convert objects that are far away from all the players to static.
		*/
		{
			core::list<u16> objects_to_remove;
			for(core::map<u16, ServerActiveObject*>::Iterator
					i = m_active_objects.getIterator();
					i.atEnd()==false; i++)
			{
				ServerActiveObject* obj = i.getNode()->getValue();
				u16 id = i.getNode()->getKey();
				v3f objectpos = obj->getBasePosition();

				// This shouldn't happen but check it
				if(obj == NULL)
				{
					dstream<<"WARNING: NULL object found in ServerEnvironment"
							<<std::endl;
					continue;
				}
				// If known by some client, don't convert to static.
				if(obj->m_known_by_count > 0)
					continue;

				// If close to some player, don't convert to static.
				bool close_to_player = false;
				for(core::list<Player*>::Iterator i = m_players.begin();
						i != m_players.end(); i++)
				{
					Player *player = *i;
					
					// Ignore disconnected players
					if(player->peer_id == 0)
						continue;

					v3f playerpos = player->getPosition();
					f32 d = playerpos.getDistanceFrom(objectpos);
					if(d < to_static_max_f)
					{
						close_to_player = true;
						break;
					}
				}

				if(close_to_player)
					continue;

				/*
					Update the static data and remove the active object.
				*/

				// Delete old static object
				MapBlock *oldblock = NULL;
				if(obj->m_static_exists)
				{
					MapBlock *block = m_map->getBlockNoCreateNoEx
							(obj->m_static_block);
					if(block)
					{
						block->m_static_objects.remove(id);
						oldblock = block;
					}
				}
				// Add new static object
				std::string staticdata = obj->getStaticData();
				StaticObject s_obj(obj->getType(), objectpos, staticdata);
				// Add to the block where the object is located in
				v3s16 blockpos = getNodeBlockPos(floatToInt(objectpos, BS));
				MapBlock *block = m_map->getBlockNoCreateNoEx(blockpos);
				if(block)
				{
					block->m_static_objects.insert(0, s_obj);
					block->setChangedFlag();
					obj->m_static_exists = true;
					obj->m_static_block = block->getPos();
				}
				// If not possible, add back to previous block
				else if(oldblock)
				{
					oldblock->m_static_objects.insert(0, s_obj);
					oldblock->setChangedFlag();
					obj->m_static_exists = true;
					obj->m_static_block = oldblock->getPos();
				}
				else{
					dstream<<"WARNING: Server: Could not find a block for "
							<<"storing static object"<<std::endl;
					obj->m_static_exists = false;
					continue;
				}
				/*dstream<<"INFO: Server: Stored static data. Deleting object."
						<<std::endl;*/
				// Delete active object
				delete obj;
				// Id to be removed from m_active_objects
				objects_to_remove.push_back(id);
			}
			// Remove references from m_active_objects
			for(core::list<u16>::Iterator i = objects_to_remove.begin();
					i != objects_to_remove.end(); i++)
			{
				m_active_objects.remove(*i);
			}
		}
	}

	if(g_settings.getBool("enable_experimental"))
	{

	/*
		TEST CODE
	*/
#if 1
	m_random_spawn_timer -= dtime;
	if(m_random_spawn_timer < 0)
	{
		//m_random_spawn_timer += myrand_range(2.0, 20.0);
		//m_random_spawn_timer += 2.0;
		m_random_spawn_timer += 200.0;

		/*
			Find some position
		*/

		/*v2s16 p2d(myrand_range(-5,5), myrand_range(-5,5));
		s16 y = 1 + getServerMap().findGroundLevel(p2d);
		v3f pos(p2d.X*BS,y*BS,p2d.Y*BS);*/
		
		Player *player = getRandomConnectedPlayer();
		v3f pos(0,0,0);
		if(player)
			pos = player->getPosition();
		pos += v3f(
			myrand_range(-3,3)*BS,
			0,
			myrand_range(-3,3)*BS
		);

		/*
			Create a ServerActiveObject
		*/

		//TestSAO *obj = new TestSAO(this, 0, pos);
		//ServerActiveObject *obj = new ItemSAO(this, 0, pos, "CraftItem Stick 1");
		ServerActiveObject *obj = new RatSAO(this, 0, pos);
		addActiveObject(obj);
	}
#endif

	} // enable_experimental
}

ServerActiveObject* ServerEnvironment::getActiveObject(u16 id)
{
	core::map<u16, ServerActiveObject*>::Node *n;
	n = m_active_objects.find(id);
	if(n == NULL)
		return NULL;
	return n->getValue();
}

bool isFreeServerActiveObjectId(u16 id,
		core::map<u16, ServerActiveObject*> &objects)
{
	if(id == 0)
		return false;
	
	for(core::map<u16, ServerActiveObject*>::Iterator
			i = objects.getIterator();
			i.atEnd()==false; i++)
	{
		if(i.getNode()->getKey() == id)
			return false;
	}
	return true;
}

u16 getFreeServerActiveObjectId(
		core::map<u16, ServerActiveObject*> &objects)
{
	u16 new_id = 1;
	for(;;)
	{
		if(isFreeServerActiveObjectId(new_id, objects))
			return new_id;
		
		if(new_id == 65535)
			return 0;

		new_id++;
	}
}

u16 ServerEnvironment::addActiveObject(ServerActiveObject *object)
{
	assert(object);
	if(object->getId() == 0)
	{
		u16 new_id = getFreeServerActiveObjectId(m_active_objects);
		if(new_id == 0)
		{
			dstream<<"WARNING: ServerEnvironment::addActiveObject(): "
					<<"no free ids available"<<std::endl;
			delete object;
			return 0;
		}
		object->setId(new_id);
	}
	if(isFreeServerActiveObjectId(object->getId(), m_active_objects) == false)
	{
		dstream<<"WARNING: ServerEnvironment::addActiveObject(): "
				<<"id is not free ("<<object->getId()<<")"<<std::endl;
		delete object;
		return 0;
	}
	/*dstream<<"INGO: ServerEnvironment::addActiveObject(): "
			<<"added (id="<<object->getId()<<")"<<std::endl;*/
			
	m_active_objects.insert(object->getId(), object);

	// Add static object to active static list of the block
	v3f objectpos = object->getBasePosition();
	std::string staticdata = object->getStaticData();
	StaticObject s_obj(object->getType(), objectpos, staticdata);
	// Add to the block where the object is located in
	v3s16 blockpos = getNodeBlockPos(floatToInt(objectpos, BS));
	MapBlock *block = m_map->getBlockNoCreateNoEx(blockpos);
	if(block)
	{
		block->m_static_objects.m_active.insert(object->getId(), s_obj);
		object->m_static_exists = true;
		object->m_static_block = blockpos;
	}
	else{
		dstream<<"WARNING: Server: Could not find a block for "
				<<"storing newly added static active object"<<std::endl;
	}

	return object->getId();
}

/*
	Finds out what new objects have been added to
	inside a radius around a position
*/
void ServerEnvironment::getAddedActiveObjects(v3s16 pos, s16 radius,
		core::map<u16, bool> &current_objects,
		core::map<u16, bool> &added_objects)
{
	v3f pos_f = intToFloat(pos, BS);
	f32 radius_f = radius * BS;
	/*
		Go through the object list,
		- discard m_removed objects,
		- discard objects that are too far away,
		- discard objects that are found in current_objects.
		- add remaining objects to added_objects
	*/
	for(core::map<u16, ServerActiveObject*>::Iterator
			i = m_active_objects.getIterator();
			i.atEnd()==false; i++)
	{
		u16 id = i.getNode()->getKey();
		// Get object
		ServerActiveObject *object = i.getNode()->getValue();
		if(object == NULL)
			continue;
		// Discard if removed
		if(object->m_removed)
			continue;
		// Discard if too far
		f32 distance_f = object->getBasePosition().getDistanceFrom(pos_f);
		if(distance_f > radius_f)
			continue;
		// Discard if already on current_objects
		core::map<u16, bool>::Node *n;
		n = current_objects.find(id);
		if(n != NULL)
			continue;
		// Add to added_objects
		added_objects.insert(id, false);
	}
}

/*
	Finds out what objects have been removed from
	inside a radius around a position
*/
void ServerEnvironment::getRemovedActiveObjects(v3s16 pos, s16 radius,
		core::map<u16, bool> &current_objects,
		core::map<u16, bool> &removed_objects)
{
	v3f pos_f = intToFloat(pos, BS);
	f32 radius_f = radius * BS;
	/*
		Go through current_objects; object is removed if:
		- object is not found in m_active_objects (this is actually an
		  error condition; objects should be set m_removed=true and removed
		  only after all clients have been informed about removal), or
		- object has m_removed=true, or
		- object is too far away
	*/
	for(core::map<u16, bool>::Iterator
			i = current_objects.getIterator();
			i.atEnd()==false; i++)
	{
		u16 id = i.getNode()->getKey();
		ServerActiveObject *object = getActiveObject(id);
		if(object == NULL)
		{
			dstream<<"WARNING: ServerEnvironment::getRemovedActiveObjects():"
					<<" object in current_objects is NULL"<<std::endl;
		}
		else if(object->m_removed == false)
		{
			f32 distance_f = object->getBasePosition().getDistanceFrom(pos_f);
			/*dstream<<"removed == false"
					<<"distance_f = "<<distance_f
					<<", radius_f = "<<radius_f<<std::endl;*/
			if(distance_f < radius_f)
			{
				// Not removed
				continue;
			}
		}
		removed_objects.insert(id, false);
	}
}

ActiveObjectMessage ServerEnvironment::getActiveObjectMessage()
{
	if(m_active_object_messages.size() == 0)
		return ActiveObjectMessage(0);
	
	return m_active_object_messages.pop_front();
}

#ifndef SERVER

/*
	ClientEnvironment
*/

ClientEnvironment::ClientEnvironment(ClientMap *map, scene::ISceneManager *smgr):
	m_map(map),
	m_smgr(smgr)
{
	assert(m_map);
	assert(m_smgr);
}

ClientEnvironment::~ClientEnvironment()
{
	// delete active objects
	for(core::map<u16, ClientActiveObject*>::Iterator
			i = m_active_objects.getIterator();
			i.atEnd()==false; i++)
	{
		delete i.getNode()->getValue();
	}

	// Drop/delete map
	m_map->drop();
}

void ClientEnvironment::addPlayer(Player *player)
{
	DSTACK(__FUNCTION_NAME);
	/*
		It is a failure if player is local and there already is a local
		player
	*/
	assert(!(player->isLocal() == true && getLocalPlayer() != NULL));

	Environment::addPlayer(player);
}

LocalPlayer * ClientEnvironment::getLocalPlayer()
{
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		if(player->isLocal())
			return (LocalPlayer*)player;
	}
	return NULL;
}

void ClientEnvironment::step(float dtime)
{
	DSTACK(__FUNCTION_NAME);

	// Get some settings
	bool free_move = g_settings.getBool("free_move");
	bool footprints = g_settings.getBool("footprints");

	{
		//TimeTaker timer("Client m_map->timerUpdate()", g_device);
		m_map->timerUpdate(dtime);
	}

	/*
		Get the speed the player is going
	*/
	f32 player_speed = 0.001; // just some small value
	LocalPlayer *lplayer = getLocalPlayer();
	if(lplayer)
		player_speed = lplayer->getSpeed().getLength();
	
	/*
		Maximum position increment
	*/
	//f32 position_max_increment = 0.05*BS;
	f32 position_max_increment = 0.1*BS;

	// Maximum time increment (for collision detection etc)
	// time = distance / speed
	f32 dtime_max_increment = position_max_increment / player_speed;
	
	// Maximum time increment is 10ms or lower
	if(dtime_max_increment > 0.01)
		dtime_max_increment = 0.01;
	
	// Don't allow overly huge dtime
	if(dtime > 0.5)
		dtime = 0.5;
	
	f32 dtime_downcount = dtime;

	/*
		Stuff that has a maximum time increment
	*/

	u32 loopcount = 0;
	do
	{
		loopcount++;

		f32 dtime_part;
		if(dtime_downcount > dtime_max_increment)
		{
			dtime_part = dtime_max_increment;
			dtime_downcount -= dtime_part;
		}
		else
		{
			dtime_part = dtime_downcount;
			/*
				Setting this to 0 (no -=dtime_part) disables an infinite loop
				when dtime_part is so small that dtime_downcount -= dtime_part
				does nothing
			*/
			dtime_downcount = 0;
		}
		
		/*
			Handle local player
		*/
		
		{
			Player *player = getLocalPlayer();

			v3f playerpos = player->getPosition();
			
			// Apply physics
			if(free_move == false)
			{
				// Gravity
				v3f speed = player->getSpeed();
				if(player->swimming_up == false)
					speed.Y -= 9.81 * BS * dtime_part * 2;

				// Water resistance
				if(player->in_water_stable || player->in_water)
				{
					f32 max_down = 2.0*BS;
					if(speed.Y < -max_down) speed.Y = -max_down;

					f32 max = 2.5*BS;
					if(speed.getLength() > max)
					{
						speed = speed / speed.getLength() * max;
					}
				}

				player->setSpeed(speed);
			}

			/*
				Move the player.
				This also does collision detection.
			*/
			player->move(dtime_part, *m_map, position_max_increment);
		}
	}
	while(dtime_downcount > 0.001);
		
	//std::cout<<"Looped "<<loopcount<<" times."<<std::endl;
	
	/*
		Stuff that can be done in an arbitarily large dtime
	*/
	for(core::list<Player*>::Iterator i = m_players.begin();
			i != m_players.end(); i++)
	{
		Player *player = *i;
		v3f playerpos = player->getPosition();
		
		/*
			Handle non-local players
		*/
		if(player->isLocal() == false)
		{
			// Move
			player->move(dtime, *m_map, 100*BS);

			// Update lighting on remote players on client
			u8 light = LIGHT_MAX;
			try{
				// Get node at head
				v3s16 p = floatToInt(playerpos + v3f(0,BS+BS/2,0), BS);
				MapNode n = m_map->getNode(p);
				light = n.getLightBlend(m_daynight_ratio);
			}
			catch(InvalidPositionException &e) {}
			player->updateLight(light);
		}
		
		/*
			Add footsteps to grass
		*/
		if(footprints)
		{
			// Get node that is at BS/4 under player
			v3s16 bottompos = floatToInt(playerpos + v3f(0,-BS/4,0), BS);
			try{
				MapNode n = m_map->getNode(bottompos);
				if(n.d == CONTENT_GRASS)
				{
					n.d = CONTENT_GRASS_FOOTSTEPS;
					m_map->setNode(bottompos, n);
					// Update mesh on client
					if(m_map->mapType() == MAPTYPE_CLIENT)
					{
						v3s16 p_blocks = getNodeBlockPos(bottompos);
						MapBlock *b = m_map->getBlockNoCreate(p_blocks);
						//b->updateMesh(m_daynight_ratio);
						b->setMeshExpired(true);
					}
				}
			}
			catch(InvalidPositionException &e)
			{
			}
		}
	}
	
	/*
		Step active objects and update lighting of them
	*/
	
	for(core::map<u16, ClientActiveObject*>::Iterator
			i = m_active_objects.getIterator();
			i.atEnd()==false; i++)
	{
		ClientActiveObject* obj = i.getNode()->getValue();
		// Step object
		obj->step(dtime, this);
		// Update lighting
		//u8 light = LIGHT_MAX;
		u8 light = 0;
		try{
			// Get node at head
			v3s16 p = obj->getLightPosition();
			MapNode n = m_map->getNode(p);
			light = n.getLightBlend(m_daynight_ratio);
		}
		catch(InvalidPositionException &e) {}
		obj->updateLight(light);
	}
}

void ClientEnvironment::updateMeshes(v3s16 blockpos)
{
	m_map->updateMeshes(blockpos, m_daynight_ratio);
}

void ClientEnvironment::expireMeshes(bool only_daynight_diffed)
{
	m_map->expireMeshes(only_daynight_diffed);
}

ClientActiveObject* ClientEnvironment::getActiveObject(u16 id)
{
	core::map<u16, ClientActiveObject*>::Node *n;
	n = m_active_objects.find(id);
	if(n == NULL)
		return NULL;
	return n->getValue();
}

bool isFreeClientActiveObjectId(u16 id,
		core::map<u16, ClientActiveObject*> &objects)
{
	if(id == 0)
		return false;
	
	for(core::map<u16, ClientActiveObject*>::Iterator
			i = objects.getIterator();
			i.atEnd()==false; i++)
	{
		if(i.getNode()->getKey() == id)
			return false;
	}
	return true;
}

u16 getFreeClientActiveObjectId(
		core::map<u16, ClientActiveObject*> &objects)
{
	u16 new_id = 1;
	for(;;)
	{
		if(isFreeClientActiveObjectId(new_id, objects))
			return new_id;
		
		if(new_id == 65535)
			return 0;

		new_id++;
	}
}

u16 ClientEnvironment::addActiveObject(ClientActiveObject *object)
{
	assert(object);
	if(object->getId() == 0)
	{
		u16 new_id = getFreeClientActiveObjectId(m_active_objects);
		if(new_id == 0)
		{
			dstream<<"WARNING: ClientEnvironment::addActiveObject(): "
					<<"no free ids available"<<std::endl;
			delete object;
			return 0;
		}
		object->setId(new_id);
	}
	if(isFreeClientActiveObjectId(object->getId(), m_active_objects) == false)
	{
		dstream<<"WARNING: ClientEnvironment::addActiveObject(): "
				<<"id is not free ("<<object->getId()<<")"<<std::endl;
		delete object;
		return 0;
	}
	dstream<<"INGO: ClientEnvironment::addActiveObject(): "
			<<"added (id="<<object->getId()<<")"<<std::endl;
	m_active_objects.insert(object->getId(), object);
	object->addToScene(m_smgr);
	return object->getId();
}

void ClientEnvironment::addActiveObject(u16 id, u8 type,
		const std::string &init_data)
{
	ClientActiveObject* obj = ClientActiveObject::create(type);
	if(obj == NULL)
	{
		dstream<<"WARNING: ClientEnvironment::addActiveObject(): "
				<<"id="<<id<<" type="<<type<<": Couldn't create object"
				<<std::endl;
		return;
	}
	
	obj->setId(id);

	addActiveObject(obj);

	obj->initialize(init_data);
}

void ClientEnvironment::removeActiveObject(u16 id)
{
	dstream<<"ClientEnvironment::removeActiveObject(): "
			<<"id="<<id<<std::endl;
	ClientActiveObject* obj = getActiveObject(id);
	if(obj == NULL)
	{
		dstream<<"WARNING: ClientEnvironment::removeActiveObject(): "
				<<"id="<<id<<" not found"<<std::endl;
		return;
	}
	obj->removeFromScene();
	delete obj;
	m_active_objects.remove(id);
}

void ClientEnvironment::processActiveObjectMessage(u16 id,
		const std::string &data)
{
	ClientActiveObject* obj = getActiveObject(id);
	if(obj == NULL)
	{
		dstream<<"WARNING: ClientEnvironment::processActiveObjectMessage():"
				<<" got message for id="<<id<<", which doesn't exist."
				<<std::endl;
		return;
	}
	obj->processMessage(data);
}

void ClientEnvironment::getActiveObjects(v3f origin, f32 max_d,
		core::array<DistanceSortedActiveObject> &dest)
{
	for(core::map<u16, ClientActiveObject*>::Iterator
			i = m_active_objects.getIterator();
			i.atEnd()==false; i++)
	{
		ClientActiveObject* obj = i.getNode()->getValue();

		f32 d = (obj->getPosition() - origin).getLength();

		if(d > max_d)
			continue;

		DistanceSortedActiveObject dso(obj, d);

		dest.push_back(dso);
	}
}


#endif // #ifndef SERVER