minetest/src/mapblock.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 "mapblock.h"

#include <sstream>
#include "map.h"
// For g_settings
#include "main.h"
#include "light.h"
#include "nodedef.h"
#include "nodemetadata.h"
#include "gamedef.h"
#include "log.h"
#include "nameidmapping.h"
#include "content_mapnode.h" // For legacy name-id mapping

/*
	MapBlock
*/

MapBlock::MapBlock(Map *parent, v3s16 pos, IGameDef *gamedef, bool dummy):
		m_node_metadata(new NodeMetadataList),
		m_parent(parent),
		m_pos(pos),
		m_gamedef(gamedef),
		m_modified(MOD_STATE_WRITE_NEEDED),
		m_modified_reason("initial"),
		m_modified_reason_too_long(false),
		is_underground(false),
		m_lighting_expired(true),
		m_day_night_differs(false),
		m_generated(false),
		m_timestamp(BLOCK_TIMESTAMP_UNDEFINED),
		m_usage_timer(0)
{
	data = NULL;
	if(dummy == false)
		reallocate();
	
#ifndef SERVER
	m_mesh_expired = false;
	mesh_mutex.Init();
	mesh = NULL;
	m_temp_mods_mutex.Init();
#endif
}

MapBlock::~MapBlock()
{
#ifndef SERVER
	{
		JMutexAutoLock lock(mesh_mutex);
		
		if(mesh)
		{
			mesh->drop();
			mesh = NULL;
		}
	}
#endif

	delete m_node_metadata;

	if(data)
		delete[] data;
}

bool MapBlock::isValidPositionParent(v3s16 p)
{
	if(isValidPosition(p))
	{
		return true;
	}
	else{
		return m_parent->isValidPosition(getPosRelative() + p);
	}
}

MapNode MapBlock::getNodeParent(v3s16 p)
{
	if(isValidPosition(p) == false)
	{
		return m_parent->getNode(getPosRelative() + p);
	}
	else
	{
		if(data == NULL)
			throw InvalidPositionException();
		return data[p.Z*MAP_BLOCKSIZE*MAP_BLOCKSIZE + p.Y*MAP_BLOCKSIZE + p.X];
	}
}

void MapBlock::setNodeParent(v3s16 p, MapNode & n)
{
	if(isValidPosition(p) == false)
	{
		m_parent->setNode(getPosRelative() + p, n);
	}
	else
	{
		if(data == NULL)
			throw InvalidPositionException();
		data[p.Z*MAP_BLOCKSIZE*MAP_BLOCKSIZE + p.Y*MAP_BLOCKSIZE + p.X] = n;
	}
}

MapNode MapBlock::getNodeParentNoEx(v3s16 p)
{
	if(isValidPosition(p) == false)
	{
		try{
			return m_parent->getNode(getPosRelative() + p);
		}
		catch(InvalidPositionException &e)
		{
			return MapNode(CONTENT_IGNORE);
		}
	}
	else
	{
		if(data == NULL)
		{
			return MapNode(CONTENT_IGNORE);
		}
		return data[p.Z*MAP_BLOCKSIZE*MAP_BLOCKSIZE + p.Y*MAP_BLOCKSIZE + p.X];
	}
}

#ifndef SERVER

#if 1
void MapBlock::updateMesh(u32 daynight_ratio)
{
#if 0
	/*
		DEBUG: If mesh has been generated, don't generate it again
	*/
	{
		JMutexAutoLock meshlock(mesh_mutex);
		if(mesh != NULL)
			return;
	}
#endif

	MeshMakeData data;
	data.fill(daynight_ratio, this);
	
	scene::SMesh *mesh_new = makeMapBlockMesh(&data, m_gamedef);
	
	/*
		Replace the mesh
	*/

	replaceMesh(mesh_new);

}
#endif

void MapBlock::replaceMesh(scene::SMesh *mesh_new)
{
	mesh_mutex.Lock();

	//scene::SMesh *mesh_old = mesh[daynight_i];
	//mesh[daynight_i] = mesh_new;

	scene::SMesh *mesh_old = mesh;
	mesh = mesh_new;
	setMeshExpired(false);
	
	if(mesh_old != NULL)
	{
		// Remove hardware buffers of meshbuffers of mesh
		// NOTE: No way, this runs in a different thread and everything
		/*u32 c = mesh_old->getMeshBufferCount();
		for(u32 i=0; i<c; i++)
		{
			IMeshBuffer *buf = mesh_old->getMeshBuffer(i);
		}*/
		
		/*infostream<<"mesh_old->getReferenceCount()="
				<<mesh_old->getReferenceCount()<<std::endl;
		u32 c = mesh_old->getMeshBufferCount();
		for(u32 i=0; i<c; i++)
		{
			scene::IMeshBuffer *buf = mesh_old->getMeshBuffer(i);
			infostream<<"buf->getReferenceCount()="
					<<buf->getReferenceCount()<<std::endl;
		}*/

		// Drop the mesh
		mesh_old->drop();

		//delete mesh_old;
	}

	mesh_mutex.Unlock();
}
	
#endif // !SERVER

/*
	Propagates sunlight down through the block.
	Doesn't modify nodes that are not affected by sunlight.
	
	Returns false if sunlight at bottom block is invalid.
	Returns true if sunlight at bottom block is valid.
	Returns true if bottom block doesn't exist.

	If there is a block above, continues from it.
	If there is no block above, assumes there is sunlight, unless
	is_underground is set or highest node is water.

	All sunlighted nodes are added to light_sources.

	if remove_light==true, sets non-sunlighted nodes black.

	if black_air_left!=NULL, it is set to true if non-sunlighted
	air is left in block.
*/
bool MapBlock::propagateSunlight(core::map<v3s16, bool> & light_sources,
		bool remove_light, bool *black_air_left)
{
	INodeDefManager *nodemgr = m_gamedef->ndef();

	// Whether the sunlight at the top of the bottom block is valid
	bool block_below_is_valid = true;
	
	v3s16 pos_relative = getPosRelative();
	
	for(s16 x=0; x<MAP_BLOCKSIZE; x++)
	{
		for(s16 z=0; z<MAP_BLOCKSIZE; z++)
		{
#if 1
			bool no_sunlight = false;
			bool no_top_block = false;
			// Check if node above block has sunlight
			try{
				MapNode n = getNodeParent(v3s16(x, MAP_BLOCKSIZE, z));
				if(n.getContent() == CONTENT_IGNORE)
				{
					// Trust heuristics
					no_sunlight = is_underground;
				}
				else if(n.getLight(LIGHTBANK_DAY, m_gamedef->ndef()) != LIGHT_SUN)
				{
					no_sunlight = true;
				}
			}
			catch(InvalidPositionException &e)
			{
				no_top_block = true;
				
				// NOTE: This makes over-ground roofed places sunlighted
				// Assume sunlight, unless is_underground==true
				if(is_underground)
				{
					no_sunlight = true;
				}
				else
				{
					MapNode n = getNode(v3s16(x, MAP_BLOCKSIZE-1, z));
					if(m_gamedef->ndef()->get(n).sunlight_propagates == false)
					{
						no_sunlight = true;
					}
				}
				// NOTE: As of now, this just would make everything dark.
				// No sunlight here
				//no_sunlight = true;
			}
#endif
#if 0 // Doesn't work; nothing gets light.
			bool no_sunlight = true;
			bool no_top_block = false;
			// Check if node above block has sunlight
			try{
				MapNode n = getNodeParent(v3s16(x, MAP_BLOCKSIZE, z));
				if(n.getLight(LIGHTBANK_DAY) == LIGHT_SUN)
				{
					no_sunlight = false;
				}
			}
			catch(InvalidPositionException &e)
			{
				no_top_block = true;
			}
#endif

			/*std::cout<<"("<<x<<","<<z<<"): "
					<<"no_top_block="<<no_top_block
					<<", is_underground="<<is_underground
					<<", no_sunlight="<<no_sunlight
					<<std::endl;*/
		
			s16 y = MAP_BLOCKSIZE-1;
			
			// This makes difference to diminishing in water.
			bool stopped_to_solid_object = false;
			
			u8 current_light = no_sunlight ? 0 : LIGHT_SUN;

			for(; y >= 0; y--)
			{
				v3s16 pos(x, y, z);
				MapNode &n = getNodeRef(pos);
				
				if(current_light == 0)
				{
					// Do nothing
				}
				else if(current_light == LIGHT_SUN && nodemgr->get(n).sunlight_propagates)
				{
					// Do nothing: Sunlight is continued
				}
				else if(nodemgr->get(n).light_propagates == false)
				{
					// A solid object is on the way.
					stopped_to_solid_object = true;
					
					// Light stops.
					current_light = 0;
				}
				else
				{
					// Diminish light
					current_light = diminish_light(current_light);
				}

				u8 old_light = n.getLight(LIGHTBANK_DAY, nodemgr);

				if(current_light > old_light || remove_light)
				{
					n.setLight(LIGHTBANK_DAY, current_light, nodemgr);
				}
				
				if(diminish_light(current_light) != 0)
				{
					light_sources.insert(pos_relative + pos, true);
				}

				if(current_light == 0 && stopped_to_solid_object)
				{
					if(black_air_left)
					{
						*black_air_left = true;
					}
				}
			}

			// Whether or not the block below should see LIGHT_SUN
			bool sunlight_should_go_down = (current_light == LIGHT_SUN);

			/*
				If the block below hasn't already been marked invalid:

				Check if the node below the block has proper sunlight at top.
				If not, the block below is invalid.
				
				Ignore non-transparent nodes as they always have no light
			*/
			try
			{
			if(block_below_is_valid)
			{
				MapNode n = getNodeParent(v3s16(x, -1, z));
				if(nodemgr->get(n).light_propagates)
				{
					if(n.getLight(LIGHTBANK_DAY, nodemgr) == LIGHT_SUN
							&& sunlight_should_go_down == false)
						block_below_is_valid = false;
					else if(n.getLight(LIGHTBANK_DAY, nodemgr) != LIGHT_SUN
							&& sunlight_should_go_down == true)
						block_below_is_valid = false;
				}
			}//if
			}//try
			catch(InvalidPositionException &e)
			{
				/*std::cout<<"InvalidBlockException for bottom block node"
						<<std::endl;*/
				// Just no block below, no need to panic.
			}
		}
	}

	return block_below_is_valid;
}


void MapBlock::copyTo(VoxelManipulator &dst)
{
	v3s16 data_size(MAP_BLOCKSIZE, MAP_BLOCKSIZE, MAP_BLOCKSIZE);
	VoxelArea data_area(v3s16(0,0,0), data_size - v3s16(1,1,1));
	
	// Copy from data to VoxelManipulator
	dst.copyFrom(data, data_area, v3s16(0,0,0),
			getPosRelative(), data_size);
}

void MapBlock::copyFrom(VoxelManipulator &dst)
{
	v3s16 data_size(MAP_BLOCKSIZE, MAP_BLOCKSIZE, MAP_BLOCKSIZE);
	VoxelArea data_area(v3s16(0,0,0), data_size - v3s16(1,1,1));
	
	// Copy from VoxelManipulator to data
	dst.copyTo(data, data_area, v3s16(0,0,0),
			getPosRelative(), data_size);
}

void MapBlock::updateDayNightDiff()
{
	INodeDefManager *nodemgr = m_gamedef->ndef();

	if(data == NULL)
	{
		m_day_night_differs = false;
		return;
	}

	bool differs = false;

	/*
		Check if any lighting value differs
	*/
	for(u32 i=0; i<MAP_BLOCKSIZE*MAP_BLOCKSIZE*MAP_BLOCKSIZE; i++)
	{
		MapNode &n = data[i];
		if(n.getLight(LIGHTBANK_DAY, nodemgr) != n.getLight(LIGHTBANK_NIGHT, nodemgr))
		{
			differs = true;
			break;
		}
	}

	/*
		If some lighting values differ, check if the whole thing is
		just air. If it is, differ = false
	*/
	if(differs)
	{
		bool only_air = true;
		for(u32 i=0; i<MAP_BLOCKSIZE*MAP_BLOCKSIZE*MAP_BLOCKSIZE; i++)
		{
			MapNode &n = data[i];
			if(n.getContent() != CONTENT_AIR)
			{
				only_air = false;
				break;
			}
		}
		if(only_air)
			differs = false;
	}

	// Set member variable
	m_day_night_differs = differs;
}

s16 MapBlock::getGroundLevel(v2s16 p2d)
{
	if(isDummy())
		return -3;
	try
	{
		s16 y = MAP_BLOCKSIZE-1;
		for(; y>=0; y--)
		{
			MapNode n = getNodeRef(p2d.X, y, p2d.Y);
			if(m_gamedef->ndef()->get(n).walkable)
			{
				if(y == MAP_BLOCKSIZE-1)
					return -2;
				else
					return y;
			}
		}
		return -1;
	}
	catch(InvalidPositionException &e)
	{
		return -3;
	}
}

/*
	Serialization
*/

// List relevant id-name pairs for ids in the block using nodedef
static void getBlockNodeIdMapping(NameIdMapping *nimap, MapBlock *block,
		INodeDefManager *nodedef)
{
	std::set<content_t> unknown_contents;
	for(s16 z0=0; z0<MAP_BLOCKSIZE; z0++)
	for(s16 y0=0; y0<MAP_BLOCKSIZE; y0++)
	for(s16 x0=0; x0<MAP_BLOCKSIZE; x0++)
	{
		v3s16 p(x0,y0,z0);
		MapNode n = block->getNode(p);
		content_t id = n.getContent();
		const ContentFeatures &f = nodedef->get(id);
		const std::string &name = f.name;
		if(name == "")
			unknown_contents.insert(id);
		else
			nimap->set(id, name);
	}
	for(std::set<content_t>::const_iterator
			i = unknown_contents.begin();
			i != unknown_contents.end(); i++){
		errorstream<<"getBlockNodeIdMapping(): IGNORING ERROR: "
				<<"Name for node id "<<(*i)<<" not known"<<std::endl;
	}
}
// Correct ids in the block to match nodedef based on names.
// Unknown ones are added to nodedef.
// Will not update itself to match id-name pairs in nodedef.
void correctBlockNodeIds(const NameIdMapping *nimap, MapBlock *block,
		IGameDef *gamedef)
{
	INodeDefManager *nodedef = gamedef->ndef();
	// This means the block contains incorrect ids, and we contain
	// the information to convert those to names.
	// nodedef contains information to convert our names to globally
	// correct ids.
	std::set<content_t> unnamed_contents;
	std::set<std::string> unallocatable_contents;
	for(s16 z0=0; z0<MAP_BLOCKSIZE; z0++)
	for(s16 y0=0; y0<MAP_BLOCKSIZE; y0++)
	for(s16 x0=0; x0<MAP_BLOCKSIZE; x0++)
	{
		v3s16 p(x0,y0,z0);
		MapNode n = block->getNode(p);
		content_t local_id = n.getContent();
		std::string name;
		bool found = nimap->getName(local_id, name);
		if(!found){
			unnamed_contents.insert(local_id);
			continue;
		}
		content_t global_id;
		found = nodedef->getId(name, global_id);
		if(!found){
			global_id = gamedef->allocateUnknownNodeId(name);
			if(global_id == CONTENT_IGNORE){
				unallocatable_contents.insert(name);
				continue;
			}
		}
		n.setContent(global_id);
		block->setNode(p, n);
	}
	for(std::set<content_t>::const_iterator
			i = unnamed_contents.begin();
			i != unnamed_contents.end(); i++){
		errorstream<<"correctBlockNodeIds(): IGNORING ERROR: "
				<<"Block contains id "<<(*i)
				<<" with no name mapping"<<std::endl;
	}
	for(std::set<std::string>::const_iterator
			i = unallocatable_contents.begin();
			i != unallocatable_contents.end(); i++){
		errorstream<<"correctBlockNodeIds(): IGNORING ERROR: "
				<<"Could not allocate global id for node name \""
				<<(*i)<<"\""<<std::endl;
	}
}

void MapBlock::serialize(std::ostream &os, u8 version)
{
	if(!ser_ver_supported(version))
		throw VersionMismatchException("ERROR: MapBlock format not supported");
	
	if(data == NULL)
	{
		throw SerializationError("ERROR: Not writing dummy block.");
	}
	
	// These have no compression
	if(version <= 3 || version == 5 || version == 6)
	{
		u32 nodecount = MAP_BLOCKSIZE*MAP_BLOCKSIZE*MAP_BLOCKSIZE;
		
		u32 buflen = 1 + nodecount * MapNode::serializedLength(version);
		SharedBuffer<u8> dest(buflen);

		dest[0] = is_underground;
		for(u32 i=0; i<nodecount; i++)
		{
			u32 s = 1 + i * MapNode::serializedLength(version);
			data[i].serialize(&dest[s], version);
		}
		
		os.write((char*)*dest, dest.getSize());
	}
	else if(version <= 10)
	{
		/*
			With compression.
			Compress the materials and the params separately.
		*/
		
		// First byte
		os.write((char*)&is_underground, 1);

		u32 nodecount = MAP_BLOCKSIZE*MAP_BLOCKSIZE*MAP_BLOCKSIZE;

		// Get and compress materials
		SharedBuffer<u8> materialdata(nodecount);
		for(u32 i=0; i<nodecount; i++)
		{
			materialdata[i] = data[i].param0;
		}
		compress(materialdata, os, version);

		// Get and compress lights
		SharedBuffer<u8> lightdata(nodecount);
		for(u32 i=0; i<nodecount; i++)
		{
			lightdata[i] = data[i].param1;
		}
		compress(lightdata, os, version);
		
		if(version >= 10)
		{
			// Get and compress param2
			SharedBuffer<u8> param2data(nodecount);
			for(u32 i=0; i<nodecount; i++)
			{
				param2data[i] = data[i].param2;
			}
			compress(param2data, os, version);
		}
	}
	// All other versions (newest)
	else
	{
		// First byte
		u8 flags = 0;
		if(is_underground)
			flags |= 0x01;
		if(m_day_night_differs)
			flags |= 0x02;
		if(m_lighting_expired)
			flags |= 0x04;
		if(version >= 18)
		{
			if(m_generated == false)
				flags |= 0x08;
		}
		os.write((char*)&flags, 1);
		
		u32 nodecount = MAP_BLOCKSIZE*MAP_BLOCKSIZE*MAP_BLOCKSIZE;

		/*
			Get data
		*/

		// Serialize nodes
		SharedBuffer<u8> databuf_nodelist(nodecount*3);
		for(u32 i=0; i<nodecount; i++)
		{
			data[i].serialize(&databuf_nodelist[i*3], version);
		}
		
		// Create buffer with different parameters sorted
		SharedBuffer<u8> databuf(nodecount*3);
		for(u32 i=0; i<nodecount; i++)
		{
			databuf[i] = databuf_nodelist[i*3];
			databuf[i+nodecount] = databuf_nodelist[i*3+1];
			databuf[i+nodecount*2] = databuf_nodelist[i*3+2];
		}

		/*
			Compress data to output stream
		*/

		compress(databuf, os, version);
		
		/*
			NodeMetadata
		*/
		if(version >= 14)
		{
			if(version <= 15)
			{
				try{
					std::ostringstream oss(std::ios_base::binary);
					m_node_metadata->serialize(oss);
					os<<serializeString(oss.str());
				}
				// This will happen if the string is longer than 65535
				catch(SerializationError &e)
				{
					// Use an empty string
					os<<serializeString("");
				}
			}
			else
			{
				std::ostringstream oss(std::ios_base::binary);
				m_node_metadata->serialize(oss);
				compressZlib(oss.str(), os);
				//os<<serializeLongString(oss.str());
			}
		}
	}
}

void MapBlock::deSerialize(std::istream &is, u8 version)
{
	if(!ser_ver_supported(version))
		throw VersionMismatchException("ERROR: MapBlock format not supported");

	// These have no lighting info
	if(version <= 1)
	{
		setLightingExpired(true);
	}

	// These have no "generated" field
	if(version < 18)
	{
		m_generated = true;
	}

	// These have no compression
	if(version <= 3 || version == 5 || version == 6)
	{
		u32 nodecount = MAP_BLOCKSIZE*MAP_BLOCKSIZE*MAP_BLOCKSIZE;
		char tmp;
		is.read(&tmp, 1);
		if(is.gcount() != 1)
			throw SerializationError
					("MapBlock::deSerialize: no enough input data");
		is_underground = tmp;
		for(u32 i=0; i<nodecount; i++)
		{
			s32 len = MapNode::serializedLength(version);
			SharedBuffer<u8> d(len);
			is.read((char*)*d, len);
			if(is.gcount() != len)
				throw SerializationError
						("MapBlock::deSerialize: no enough input data");
			data[i].deSerialize(*d, version);
		}
	}
	else if(version <= 10)
	{
		u32 nodecount = MAP_BLOCKSIZE*MAP_BLOCKSIZE*MAP_BLOCKSIZE;

		u8 t8;
		is.read((char*)&t8, 1);
		is_underground = t8;

		{
			// Uncompress and set material data
			std::ostringstream os(std::ios_base::binary);
			decompress(is, os, version);
			std::string s = os.str();
			if(s.size() != nodecount)
				throw SerializationError
						("MapBlock::deSerialize: invalid format");
			for(u32 i=0; i<s.size(); i++)
			{
				data[i].param0 = s[i];
			}
		}
		{
			// Uncompress and set param data
			std::ostringstream os(std::ios_base::binary);
			decompress(is, os, version);
			std::string s = os.str();
			if(s.size() != nodecount)
				throw SerializationError
						("MapBlock::deSerialize: invalid format");
			for(u32 i=0; i<s.size(); i++)
			{
				data[i].param1 = s[i];
			}
		}
	
		if(version >= 10)
		{
			// Uncompress and set param2 data
			std::ostringstream os(std::ios_base::binary);
			decompress(is, os, version);
			std::string s = os.str();
			if(s.size() != nodecount)
				throw SerializationError
						("MapBlock::deSerialize: invalid format");
			for(u32 i=0; i<s.size(); i++)
			{
				data[i].param2 = s[i];
			}
		}
	}
	// All other versions (newest)
	else
	{
		u32 nodecount = MAP_BLOCKSIZE*MAP_BLOCKSIZE*MAP_BLOCKSIZE;

		u8 flags;
		is.read((char*)&flags, 1);
		is_underground = (flags & 0x01) ? true : false;
		m_day_night_differs = (flags & 0x02) ? true : false;
		m_lighting_expired = (flags & 0x04) ? true : false;
		if(version >= 18)
			m_generated = (flags & 0x08) ? false : true;

		// Uncompress data
		std::ostringstream os(std::ios_base::binary);
		decompress(is, os, version);
		std::string s = os.str();
		if(s.size() != nodecount*3)
			throw SerializationError
					("MapBlock::deSerialize: decompress resulted in size"
					" other than nodecount*3");

		// deserialize nodes from buffer
		for(u32 i=0; i<nodecount; i++)
		{
			u8 buf[3];
			buf[0] = s[i];
			buf[1] = s[i+nodecount];
			buf[2] = s[i+nodecount*2];
			data[i].deSerialize(buf, version);
		}
		
		/*
			NodeMetadata
		*/
		if(version >= 14)
		{
			// Ignore errors
			try{
				if(version <= 15)
				{
					std::string data = deSerializeString(is);
					std::istringstream iss(data, std::ios_base::binary);
					m_node_metadata->deSerialize(iss, m_gamedef);
				}
				else
				{
					//std::string data = deSerializeLongString(is);
					std::ostringstream oss(std::ios_base::binary);
					decompressZlib(is, oss);
					std::istringstream iss(oss.str(), std::ios_base::binary);
					m_node_metadata->deSerialize(iss, m_gamedef);
				}
			}
			catch(SerializationError &e)
			{
				errorstream<<"WARNING: MapBlock::deSerialize(): Ignoring an error"
						<<" while deserializing node metadata"<<std::endl;
			}
		}
	}
}

void MapBlock::serializeDiskExtra(std::ostream &os, u8 version)
{
	// Versions up from 9 have block objects. (DEPRECATED)
	if(version >= 9)
	{
		// count=0
		writeU16(os, 0);
	}
	
	// Versions up from 15 have static objects.
	if(version >= 15)
	{
		m_static_objects.serialize(os);
	}

	// Timestamp
	if(version >= 17)
	{
		writeU32(os, getTimestamp());
	}

	// Scan and write node definition id mapping
	if(version >= 21){
		NameIdMapping nimap;
		getBlockNodeIdMapping(&nimap, this, m_gamedef->ndef());
		nimap.serialize(os);
	}
}

void MapBlock::deSerializeDiskExtra(std::istream &is, u8 version)
{
	/*
		Versions up from 9 have block objects. (DEPRECATED)
	*/
	if(version >= 9){
		u16 count = readU16(is);
		// Not supported and length not known if count is not 0
		if(count != 0){
			errorstream<<"WARNING: MapBlock::deSerializeDiskExtra(): "
					<<"Ignoring stuff coming at and after MBOs"<<std::endl;
			return;
		}
	}

	/*
		Versions up from 15 have static objects.
	*/
	if(version >= 15)
		m_static_objects.deSerialize(is);
		
	// Timestamp
	if(version >= 17)
		setTimestamp(readU32(is));
	else
		setTimestamp(BLOCK_TIMESTAMP_UNDEFINED);
	
	// Dynamically re-set ids based on node names
	NameIdMapping nimap;
	// If supported, read node definition id mapping
	if(version >= 21){
		nimap.deSerialize(is);
	// Else set the legacy mapping
	} else {
		content_mapnode_get_name_id_mapping(&nimap);
	}
	correctBlockNodeIds(&nimap, this, m_gamedef);
}

/*
	Get a quick string to describe what a block actually contains
*/
std::string analyze_block(MapBlock *block)
{
	if(block == NULL)
		return "NULL";

	std::ostringstream desc;
	
	v3s16 p = block->getPos();
	char spos[20];
	snprintf(spos, 20, "(%2d,%2d,%2d), ", p.X, p.Y, p.Z);
	desc<<spos;
	
	switch(block->getModified())
	{
	case MOD_STATE_CLEAN:
		desc<<"CLEAN,           ";
		break;
	case MOD_STATE_WRITE_AT_UNLOAD:
		desc<<"WRITE_AT_UNLOAD, ";
		break;
	case MOD_STATE_WRITE_NEEDED:
		desc<<"WRITE_NEEDED,    ";
		break;
	default:
		desc<<"unknown getModified()="+itos(block->getModified())+", ";
	}

	if(block->isGenerated())
		desc<<"is_gen [X], ";
	else
		desc<<"is_gen [ ], ";

	if(block->getIsUnderground())
		desc<<"is_ug [X], ";
	else
		desc<<"is_ug [ ], ";

#ifndef SERVER
	if(block->getMeshExpired())
		desc<<"mesh_exp [X], ";
	else
		desc<<"mesh_exp [ ], ";
#endif

	if(block->getLightingExpired())
		desc<<"lighting_exp [X], ";
	else
		desc<<"lighting_exp [ ], ";

	if(block->isDummy())
	{
		desc<<"Dummy, ";
	}
	else
	{
		bool full_ignore = true;
		bool some_ignore = false;
		bool full_air = true;
		bool some_air = false;
		for(s16 z0=0; z0<MAP_BLOCKSIZE; z0++)
		for(s16 y0=0; y0<MAP_BLOCKSIZE; y0++)
		for(s16 x0=0; x0<MAP_BLOCKSIZE; x0++)
		{
			v3s16 p(x0,y0,z0);
			MapNode n = block->getNode(p);
			content_t c = n.getContent();
			if(c == CONTENT_IGNORE)
				some_ignore = true;
			else
				full_ignore = false;
			if(c == CONTENT_AIR)
				some_air = true;
			else
				full_air = false;
		}
		
		desc<<"content {";
		
		std::ostringstream ss;
		
		if(full_ignore)
			ss<<"IGNORE (full), ";
		else if(some_ignore)
			ss<<"IGNORE, ";
		
		if(full_air)
			ss<<"AIR (full), ";
		else if(some_air)
			ss<<"AIR, ";
		
		if(ss.str().size()>=2)
			desc<<ss.str().substr(0, ss.str().size()-2);

		desc<<"}, ";
	}

	return desc.str().substr(0, desc.str().size()-2);
}


//END