9 files changed, 386 insertions, 121 deletions

diff --git a/source/Chunk.cpp b/source/Chunk.cpp
index 763555083..7c8d8744e 100644
--- a/source/Chunk.cpp
+++ b/source/Chunk.cpp
@@ -434,6 +434,9 @@ void cChunk::Tick(float a_Dt, MTRand & a_TickRandom)
 
 	CheckBlocks();
 	
+	// Tick simulators:
+	m_World->GetSimulatorManager()->SimulateChunk(a_Dt, m_PosX, m_PosZ, this);
+	
 	TickBlocks(a_TickRandom);
 
 	// Tick block entities (furnaces)
@@ -1208,7 +1211,7 @@ void cChunk::QueueTickBlockNeighbors(int a_RelX, int a_RelY, int a_RelZ)
 	} ;
 	for (int i = 0; i < ARRAYCOUNT(Coords); i++)
 	{
-		cChunk * ch = GetRelNeighborChunk(a_RelX + Coords[i].x, a_RelY, a_RelZ + Coords[i].z);
+		cChunk * ch = GetRelNeighborChunk(a_RelX + Coords[i].x, a_RelZ + Coords[i].z);
 		if (ch != NULL)
 		{
 			ch->QueueTickBlock(a_RelX + Coords[i].x, a_RelY + Coords[i].y, a_RelZ + Coords[i].z);
@@ -1310,7 +1313,7 @@ void cChunk::SendBlockTo(int a_RelX, int a_RelY, int a_RelZ, cClientHandle * a_C
 
 
 
-void cChunk::AddBlockEntity( cBlockEntity* a_BlockEntity )
+void cChunk::AddBlockEntity(cBlockEntity * a_BlockEntity)
 {
 	cCSLock Lock(m_CSBlockLists);
 	m_BlockEntities.push_back( a_BlockEntity );
@@ -1320,14 +1323,14 @@ void cChunk::AddBlockEntity( cBlockEntity* a_BlockEntity )
 
 
 
-cBlockEntity * cChunk::GetBlockEntity(int a_X, int a_Y, int a_Z)
+cBlockEntity * cChunk::GetBlockEntity(int a_BlockX, int a_BlockY, int a_BlockZ)
 {
 	for (cBlockEntityList::iterator itr = m_BlockEntities.begin(); itr != m_BlockEntities.end(); ++itr)
 	{
 		if (
-			((*itr)->GetPosX() == a_X) &&
-			((*itr)->GetPosY() == a_Y) &&
-			((*itr)->GetPosZ() == a_Z)
+			((*itr)->GetPosX() == a_BlockX) &&
+			((*itr)->GetPosY() == a_BlockY) &&
+			((*itr)->GetPosZ() == a_BlockZ)
 		)
 		{
 			return *itr;
@@ -1803,26 +1806,26 @@ void cChunk::GetBlockInfo(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE & a_Bloc
 
 
 
-cChunk * cChunk::GetNeighborChunk(int a_BlockX, int a_BlockY, int a_BlockZ)
+cChunk * cChunk::GetNeighborChunk(int a_BlockX, int a_BlockZ)
 {
 	// Convert coords to relative, then call the relative version:
 	a_BlockX -= m_PosX * cChunkDef::Width;
 	a_BlockZ -= m_PosZ * cChunkDef::Width;
-	return GetRelNeighborChunk(a_BlockX, a_BlockY, a_BlockZ);
+	return GetRelNeighborChunk(a_BlockX, a_BlockZ);
 }
 
 
 
 
 
-cChunk * cChunk::GetRelNeighborChunk(int a_RelX, int a_RelY, int a_RelZ)
+cChunk * cChunk::GetRelNeighborChunk(int a_RelX, int a_RelZ)
 {
 	bool ReturnThis = true;
 	if (a_RelX < 0)
 	{
 		if (m_NeighborXM != NULL)
 		{
-			cChunk * Candidate = m_NeighborXM->GetRelNeighborChunk(a_RelX + cChunkDef::Width, a_RelY, a_RelZ);
+			cChunk * Candidate = m_NeighborXM->GetRelNeighborChunk(a_RelX + cChunkDef::Width, a_RelZ);
 			if (Candidate != NULL)
 			{
 				return Candidate;
@@ -1835,7 +1838,7 @@ cChunk * cChunk::GetRelNeighborChunk(int a_RelX, int a_RelY, int a_RelZ)
 	{
 		if (m_NeighborXP != NULL)
 		{
-			cChunk * Candidate = m_NeighborXP->GetRelNeighborChunk(a_RelX - cChunkDef::Width, a_RelY, a_RelZ);
+			cChunk * Candidate = m_NeighborXP->GetRelNeighborChunk(a_RelX - cChunkDef::Width, a_RelZ);
 			if (Candidate != NULL)
 			{
 				return Candidate;
@@ -1849,7 +1852,7 @@ cChunk * cChunk::GetRelNeighborChunk(int a_RelX, int a_RelY, int a_RelZ)
 	{
 		if (m_NeighborZM != NULL)
 		{
-			return m_NeighborZM->GetRelNeighborChunk(a_RelX, a_RelY, a_RelZ + cChunkDef::Width);
+			return m_NeighborZM->GetRelNeighborChunk(a_RelX, a_RelZ + cChunkDef::Width);
 			// For requests crossing both X and Z, the X-first way has been already tried
 		}
 		return NULL;
@@ -1858,7 +1861,7 @@ cChunk * cChunk::GetRelNeighborChunk(int a_RelX, int a_RelY, int a_RelZ)
 	{																																																 
 		if (m_NeighborZP != NULL)
 		{
-			return m_NeighborZP->GetRelNeighborChunk(a_RelX, a_RelY, a_RelZ - cChunkDef::Width);
+			return m_NeighborZP->GetRelNeighborChunk(a_RelX, a_RelZ - cChunkDef::Width);
 			// For requests crossing both X and Z, the X-first way has been already tried
 		}
 		return NULL;
diff --git a/source/Chunk.h b/source/Chunk.h
index 324929cac..826e8bb6d 100644
--- a/source/Chunk.h
+++ b/source/Chunk.h
@@ -4,6 +4,8 @@
 #include "Entity.h"
 #include "ChunkDef.h"
 
+#include "Simulator/FireSimulator.h"
+
 
 
 
@@ -147,13 +149,13 @@ public:
 	/** Returns the chunk into which the specified block belongs, by walking the neighbors.
 	Will return self if appropriate. Returns NULL if not reachable through neighbors.
 	*/
-	cChunk * GetNeighborChunk(int a_BlockX, int a_BlockY, int a_BlockZ);
+	cChunk * GetNeighborChunk(int a_BlockX, int a_BlockZ);
 	
 	/**
 	Returns the chunk into which the relatively-specified block belongs, by walking the neighbors.
 	Will return self if appropriate. Returns NULL if not reachable through neighbors.
 	*/
-	cChunk * GetRelNeighborChunk(int a_RelX, int a_RelY, int a_RelZ);
+	cChunk * GetRelNeighborChunk(int a_RelX, int a_RelZ);
 	
 	EMCSBiome GetBiomeAt(int a_RelX, int a_RelZ) const {return cChunkDef::GetBiome(m_BiomeMap, a_RelX, a_RelZ); }
 	
@@ -250,9 +252,22 @@ public:
 	inline NIBBLETYPE GetMeta(int a_RelX, int a_RelY, int a_RelZ)                    {return cChunkDef::GetNibble(m_BlockMeta, a_RelX, a_RelY, a_RelZ); }
 	inline NIBBLETYPE GetMeta(int a_BlockIdx)                                        {return cChunkDef::GetNibble(m_BlockMeta, a_BlockIdx); }
 	inline void       SetMeta(int a_RelX, int a_RelY, int a_RelZ, NIBBLETYPE a_Meta) {       cChunkDef::SetNibble(m_BlockMeta, a_RelX, a_RelY, a_RelZ, a_Meta); }
+	inline void       SetMeta(int a_BlockIdx, NIBBLETYPE a_Meta)                     {       cChunkDef::SetNibble(m_BlockMeta, a_BlockIdx, a_Meta); }
 
 	inline NIBBLETYPE GetBlockLight(int a_RelX, int a_RelY, int a_RelZ) {return cChunkDef::GetNibble(m_BlockLight, a_RelX, a_RelY, a_RelZ); }
 	inline NIBBLETYPE GetSkyLight  (int a_RelX, int a_RelY, int a_RelZ) {return cChunkDef::GetNibble(m_BlockSkyLight, a_RelX, a_RelY, a_RelZ); }
+	
+	/// Same as GetBlock(), but relative coords needn't be in this chunk (uses m_Neighbor-s or m_ChunkMap in such a case); returns true on success; only usable in Tick()
+	bool UnboundedRelGetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE & a_BlockType, NIBBLETYPE & a_BlockMeta);
+	
+	/// Same as SetBlock(), but relative coords needn't be in this chunk (uses m_Neighbor-s or m_ChunkMap in such a case); returns true on success; only usable in Tick()
+	bool UnboundedRelSetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta);
+
+	/// Same as FastSetBlock(), but relative coords needn't be in this chunk (uses m_Neighbor-s or m_ChunkMap in such a case); returns true on success; only usable in Tick()
+	bool UnboundedRelFastSetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta);
+
+	// Simulator data:
+	cFireSimulatorChunkData & GetFireSimulatorData(void) { return m_FireSimulatorData; }
 
 private:
 
@@ -296,11 +311,14 @@ private:
 	cChunk * m_NeighborXP;  // Neighbor at [X + 1, Z]
 	cChunk * m_NeighborZM;  // Neighbor at [X,     Z - 1]
 	cChunk * m_NeighborZP;  // Neighbor at [X,     Z + 1]
+	
+	cFireSimulatorChunkData m_FireSimulatorData;
+
 
-	void RemoveBlockEntity( cBlockEntity* a_BlockEntity );
-	void AddBlockEntity( cBlockEntity* a_BlockEntity );
-	cBlockEntity * GetBlockEntity( int a_X, int a_Y, int a_Z );
-	cBlockEntity * GetBlockEntity( const Vector3i & a_BlockPos ) { return GetBlockEntity( a_BlockPos.x, a_BlockPos.y, a_BlockPos.z ); }
+	void RemoveBlockEntity(cBlockEntity * a_BlockEntity);
+	void AddBlockEntity   (cBlockEntity * a_BlockEntity);
+	cBlockEntity * GetBlockEntity(int a_BlockX, int a_BlockY, int a_BlockZ);
+	cBlockEntity * GetBlockEntity(const Vector3i & a_BlockPos) { return GetBlockEntity(a_BlockPos.x, a_BlockPos.y, a_BlockPos.z); }
 
 	void SpreadLightOfBlock(NIBBLETYPE * a_LightBuffer, int a_X, int a_Y, int a_Z, char a_Falloff);
 
@@ -331,15 +349,6 @@ private:
 	
 	/// Checks if a leaves block at the specified coords has a log up to 4 blocks away connected by other leaves blocks (false if no log)
 	bool HasNearLog(cBlockArea & a_Area, int a_BlockX, int a_BlockY, int a_BlockZ);
-	
-	/// Same as GetBlock(), but relative coords needn't be in this chunk (uses m_Neighbor-s or m_ChunkMap in such a case); returns true on success; only usable in Tick()
-	bool UnboundedRelGetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE & a_BlockType, NIBBLETYPE & a_BlockMeta);
-	
-	/// Same as SetBlock(), but relative coords needn't be in this chunk (uses m_Neighbor-s or m_ChunkMap in such a case); returns true on success; only usable in Tick()
-	bool UnboundedRelSetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta);
-
-	/// Same as FastSetBlock(), but relative coords needn't be in this chunk (uses m_Neighbor-s or m_ChunkMap in such a case); returns true on success; only usable in Tick()
-	bool UnboundedRelFastSetBlock(int a_RelX, int a_RelY, int a_RelZ, BLOCKTYPE a_BlockType, NIBBLETYPE a_BlockMeta);
 };
 
 typedef cChunk * cChunkPtr;
diff --git a/source/ChunkDef.h b/source/ChunkDef.h
index 9e5f190b8..b0d053b5e 100644
--- a/source/ChunkDef.h
+++ b/source/ChunkDef.h
@@ -516,3 +516,31 @@ public:
 
 
 
+
+/// Generic template that can store any kind of data together with a triplet of 3 coords:
+template <typename X> class cCoordWithData
+{
+public:
+	int x;
+	int y;
+	int z;
+	X   Data;
+	
+	cCoordWithData<typename X>(int a_X, int a_Y, int a_Z) :
+		x(a_X), y(a_Y), z(a_Z)
+	{
+	}
+	
+	cCoordWithData<typename X>(int a_X, int a_Y, int a_Z, const X & a_Data) :
+		x(a_X), y(a_Y), z(a_Z), Data(a_Data)
+	{
+	}
+} ;
+
+// Illegal in C++03: typedef std::list< cCoordWithData<X> > cCoordWithDataList<X>;
+typedef cCoordWithData<int>      cCoordWithInt;
+typedef std::list<cCoordWithInt> cCoordWithIntList;
+
+
+
+
diff --git a/source/Simulator/FireSimulator.cpp b/source/Simulator/FireSimulator.cpp
index 277ac0700..c9ade90c9 100644
--- a/source/Simulator/FireSimulator.cpp
+++ b/source/Simulator/FireSimulator.cpp
@@ -5,17 +5,73 @@
 #include "../World.h"
 #include "../BlockID.h"
 #include "../Defines.h"
+#include "../Chunk.h"
 
 
 
 
 
-cFireSimulator::cFireSimulator(cWorld & a_World)
-	: cSimulator(a_World)
-	, m_Blocks(new BlockList)
-	, m_Buffer(new BlockList)
-	, m_BurningBlocks(new BlockList)
+// Easy switch for turning on debugging logging:
+#if 0
+	#define FLOG LOGD
+#else
+	#define FLOG(...)
+#endif
+
+
+
+
+
+#define MAX_CHANCE_REPLACE_FUEL 100000
+#define MAX_CHANCE_FLAMMABILITY 100000
+
+
+
+
+
+static const struct
+{
+	int x, y, z;
+} gCrossCoords[] =
+{
+	{ 1, 0,  0},
+	{-1, 0,  0},
+	{ 0, 0,  1},
+	{ 0, 0, -1},
+} ;
+
+
+
+
+
+static const struct
+{
+	int x, y, z;
+} gNeighborCoords[] =
+{
+	{ 1,  0,  0},
+	{-1,  0,  0},
+	{ 0,  1,  0},
+	{ 0, -1,  0},
+	{ 0,  0,  1},
+	{ 0,  0, -1},
+} ;
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cFireSimulator:
+
+cFireSimulator::cFireSimulator(cWorld & a_World, cIniFile & a_IniFile) :
+	cSimulator(a_World)
 {
+	// Read params from the ini file:
+	m_BurnStepTimeFuel    = a_IniFile.GetValueSetI("FireSimulator", "BurnStepTimeFuel",     500);
+	m_BurnStepTimeNonfuel = a_IniFile.GetValueSetI("FireSimulator", "BurnStepTimeNonfuel",  100);
+	m_Flammability        = a_IniFile.GetValueSetI("FireSimulator", "Flammability",          50);
+	m_ReplaceFuelChance   = a_IniFile.GetValueSetI("FireSimulator", "ReplaceFuelChance",  50000);
 }
 
 
@@ -24,43 +80,64 @@ cFireSimulator::cFireSimulator(cWorld & a_World)
 
 cFireSimulator::~cFireSimulator()
 {
-	delete m_Buffer;
-	delete m_Blocks;
-	delete m_BurningBlocks;
 }
 
 
 
 
 
-void cFireSimulator::Simulate(float a_Dt)
+void cFireSimulator::SimulateChunk(float a_Dt, int a_ChunkX, int a_ChunkZ, cChunk * a_Chunk)
 {
-	m_Buffer->clear();
-	std::swap(m_Blocks, m_Buffer);
+	cCoordWithIntList & Data = a_Chunk->GetFireSimulatorData();
 
-	for (BlockList::iterator itr = m_Buffer->begin(); itr != m_Buffer->end(); ++itr)
+	int NumMSecs = (int)a_Dt;
+	for (cCoordWithIntList::iterator itr = Data.begin(); itr != Data.end();)
 	{
-		Vector3i Pos = *itr;
+		int idx = cChunkDef::MakeIndexNoCheck(itr->x, itr->y, itr->z);
+		BLOCKTYPE BlockType = a_Chunk->GetBlock(idx);
 
-		BLOCKTYPE BlockID = m_World.GetBlock(Pos.x, Pos.y, Pos.z);
-
-		if (!IsAllowedBlock(BlockID))	 // Check wheather the block is still burning
+		if (!IsAllowedBlock(BlockType))
 		{
+			// The block is no longer eligible (not a fire block anymore; a player probably placed a block over the fire)
+			FLOG("FS: Removing block {%d, %d, %d}",
+				itr->x + a_ChunkX * cChunkDef::Width, itr->y, itr->z + a_ChunkZ * cChunkDef::Width
+			);
+			itr = Data.erase(itr);
 			continue;
 		}
 
-		if (BurnBlockAround(Pos.x, Pos.y, Pos.z))	//Burn single block and if there was one -> next time again
+		// Try to spread the fire:
+		TrySpreadFire(a_Chunk, itr->x, itr->y, itr->z);
+
+		itr->Data -= NumMSecs;
+		if (itr->Data >= 0)
 		{
-			m_Blocks->push_back(Pos);
+			// Not yet, wait for it longer
+			++itr;
+			continue;
 		}
-		else
+		
+		// Burn out the fire one step by increasing the meta:
+		/*
+		FLOG("FS: Fire at {%d, %d, %d} is stepping",
+			itr->x + a_ChunkX * cChunkDef::Width, itr->y, itr->z + a_ChunkZ * cChunkDef::Width
+		);
+		*/
+		NIBBLETYPE BlockMeta = a_Chunk->GetMeta(idx);
+		if (BlockMeta == 0x0f)
 		{
-			if (!IsForeverBurnable(m_World.GetBlock(Pos.x, Pos.y - 1, Pos.z)) && !FiresForever(BlockID))
-			{
-				m_World.SetBlock(Pos.x, Pos.y, Pos.z, E_BLOCK_AIR, 0);
-			}
+			// The fire burnt out completely
+			FLOG("FS: Fire at {%d, %d, %d} burnt out, removing the fire block",
+				itr->x + a_ChunkX * cChunkDef::Width, itr->y, itr->z + a_ChunkZ * cChunkDef::Width
+			);
+			a_Chunk->SetBlock(itr->x, itr->y, itr->z, E_BLOCK_AIR, 0);
+			RemoveFuelNeighbors(a_Chunk, itr->x, itr->y, itr->z);
+			itr = Data.erase(itr);
+			continue;
 		}
-	}  // for itr - m_Buffer[]
+		a_Chunk->SetMeta(idx, BlockMeta + 1);
+		itr->Data = GetBurnStepTime(a_Chunk, itr->x, itr->y, itr->z);  // TODO: Add some randomness into this
+	}  // for itr - Data[]
 }
 
 
@@ -69,106 +146,214 @@ void cFireSimulator::Simulate(float a_Dt)
 
 bool cFireSimulator::IsAllowedBlock(BLOCKTYPE a_BlockType)
 {
-	return (a_BlockType == E_BLOCK_FIRE) || IsBlockLava(a_BlockType);
+	return (a_BlockType == E_BLOCK_FIRE);
 }
 
 
 
 
 
-void cFireSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk)
+bool cFireSimulator::IsFuel(BLOCKTYPE a_BlockType)
 {
-	// TODO: This can be optimized
-	BLOCKTYPE BlockType = m_World.GetBlock(a_BlockX, a_BlockY, a_BlockZ);
-	if (!IsAllowedBlock(BlockType))
-	{
-		return;
-	}
-	
-	// Check for duplicates:
-	for (BlockList::iterator itr = m_Blocks->begin(); itr != m_Blocks->end(); ++itr )
+	switch (a_BlockType)
 	{
-		Vector3i Pos = *itr;
-		if ((Pos.x == a_BlockX) && (Pos.y == a_BlockY) && (Pos.z == a_BlockZ))
+		case E_BLOCK_PLANKS:
+		case E_BLOCK_LEAVES:
+		case E_BLOCK_LOG:
+		case E_BLOCK_WOOL:
+		case E_BLOCK_BOOKCASE:
+		case E_BLOCK_FENCE:
+		case E_BLOCK_TNT:
+		case E_BLOCK_VINES:
 		{
-			return;
+			return true;
 		}
 	}
+	return false;
+}
+
+
 
-	m_Blocks->push_back(Vector3i(a_BlockX, a_BlockY, a_BlockZ));
+
+
+bool cFireSimulator::IsForever(BLOCKTYPE a_BlockType)
+{
+	return (a_BlockType == E_BLOCK_NETHERRACK);
 }
 
 
 
 
 
-bool cFireSimulator::IsForeverBurnable( BLOCKTYPE a_BlockType )
+void cFireSimulator::AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk)
 {
-	return a_BlockType == E_BLOCK_NETHERRACK;
+	int RelX = a_BlockX - a_Chunk->GetPosX() * cChunkDef::Width;
+	int RelZ = a_BlockZ - a_Chunk->GetPosZ() * cChunkDef::Width;
+	BLOCKTYPE BlockType = a_Chunk->GetBlock(RelX, a_BlockY, RelZ);
+	if (!IsAllowedBlock(BlockType))
+	{
+		return;
+	}
+	
+	// Check for duplicates:
+	cFireSimulatorChunkData & ChunkData = a_Chunk->GetFireSimulatorData();
+	for (cCoordWithIntList::iterator itr = ChunkData.begin(), end = ChunkData.end(); itr != end; ++itr)
+	{
+		if ((itr->x == RelX) && (itr->y == a_BlockY) && (itr->z == RelZ))
+		{
+			// Already present, skip adding
+			return;
+		}
+	}  // for itr - ChunkData[]
+
+	FLOG("FS: Adding block {%d, %d, %d}", a_BlockX, a_BlockY, a_BlockZ);
+	ChunkData.push_back(cCoordWithInt(RelX, a_BlockY, RelZ, 100));
 }
 
 
 
 
 
-bool cFireSimulator::IsBurnable( BLOCKTYPE a_BlockType )
+int cFireSimulator::GetBurnStepTime(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ)
 {
-	return a_BlockType == E_BLOCK_PLANKS
-		|| a_BlockType == E_BLOCK_LEAVES
-		|| a_BlockType == E_BLOCK_LOG
-		|| a_BlockType == E_BLOCK_WOOL
-		|| a_BlockType == E_BLOCK_BOOKCASE
-		|| a_BlockType == E_BLOCK_FENCE
-		|| a_BlockType == E_BLOCK_TNT
-		|| a_BlockType == E_BLOCK_VINES;
+	if (a_RelY > 0)
+	{
+		BLOCKTYPE BlockBelow = a_Chunk->GetBlock(a_RelX, a_RelY - 1, a_RelZ);
+		if (IsForever(BlockBelow))
+		{
+			// Is burning atop of netherrack, burn forever (re-check in 10 sec)
+			return 10000;
+		}
+		if (IsFuel(BlockBelow))
+		{
+			return m_BurnStepTimeFuel;
+		}
+	}
+	if ((a_RelY < cChunkDef::Height - 1) && IsFuel(a_Chunk->GetBlock(a_RelX, a_RelY - 1, a_RelZ)))
+	{
+		return m_BurnStepTimeFuel;
+	}
+	
+	for (int i = 0; i < ARRAYCOUNT(gCrossCoords); i++)
+	{
+		BLOCKTYPE  BlockType;
+		NIBBLETYPE BlockMeta;
+		if (a_Chunk->UnboundedRelGetBlock(a_RelX + gCrossCoords[i].x, a_RelY, a_RelZ + gCrossCoords[i].z, BlockType, BlockMeta))
+		{
+			if (IsFuel(BlockType))
+			{
+				return m_BurnStepTimeFuel;
+			}
+		}
+	}  // for i - gCrossCoords[]
+	return m_BurnStepTimeNonfuel;
 }
 
 
 
 
 
-bool cFireSimulator::FiresForever( BLOCKTYPE a_BlockType )
+void cFireSimulator::TrySpreadFire(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ)
 {
-	return a_BlockType != E_BLOCK_FIRE;
+	/*
+	if (m_World.GetTickRandomNumber(10000) > 100)
+	{
+		// Make the chance to spread 100x smaller
+		return;
+	}
+	*/
+	
+	for (int x = a_RelX - 1; x <= a_RelX + 1; x++)
+	{
+		for (int z = a_RelZ - 1; z <= a_RelZ + 1; z++)
+		{
+			for (int y = a_RelY - 1; y <= a_RelY + 2; y++)  // flames spread up one more block than around
+			{
+				// No need to check the coords for equality with the parent block,
+				// it cannot catch fire anyway (because it's not an air block)
+				
+				if (m_World.GetTickRandomNumber(MAX_CHANCE_FLAMMABILITY) > m_Flammability) 
+				{
+					continue;
+				}
+				
+				// Start the fire in the neighbor {x, y, z}
+				/*
+				FLOG("FS: Trying to start fire at {%d, %d, %d}.", 
+					x + a_Chunk->GetPosX() * cChunkDef::Width, y, z + a_Chunk->GetPosZ() * cChunkDef::Width
+				);
+				*/
+				if (CanStartFireInBlock(a_Chunk, x, y, z))
+				{
+					FLOG("FS: Starting new fire at {%d, %d, %d}.", 
+						x + a_Chunk->GetPosX() * cChunkDef::Width, y, z + a_Chunk->GetPosZ() * cChunkDef::Width
+					);
+					a_Chunk->UnboundedRelSetBlock(x, y, z, E_BLOCK_FIRE, 0);
+				}
+			}  // for y
+		}  // for z
+	}  // for x
 }
 
 
 
 
 
-bool cFireSimulator::BurnBlockAround(int a_X, int a_Y, int a_Z)
+void cFireSimulator::RemoveFuelNeighbors(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ)
 {
-	return BurnBlock(a_X + 1, a_Y, a_Z)
-		|| BurnBlock(a_X - 1, a_Y, a_Z)
-		|| BurnBlock(a_X, a_Y + 1, a_Z)
-		|| BurnBlock(a_X, a_Y - 1, a_Z)
-		|| BurnBlock(a_X, a_Y, a_Z + 1)
-		|| BurnBlock(a_X, a_Y, a_Z - 1);
+	for (int i = 0; i < ARRAYCOUNT(gNeighborCoords); i++)
+	{
+		BLOCKTYPE  BlockType;
+		NIBBLETYPE BlockMeta;
+		if (!a_Chunk->UnboundedRelGetBlock(a_RelX + gNeighborCoords[i].x, a_RelY + gNeighborCoords[i].y, a_RelZ + gNeighborCoords[i].z, BlockType, BlockMeta))
+		{
+			// Neighbor not accessible, ignore it
+			continue;
+		}
+		if (!IsFuel(BlockType))
+		{
+			continue;
+		}
+		bool ShouldReplaceFuel = (m_World.GetTickRandomNumber(MAX_CHANCE_REPLACE_FUEL) < m_ReplaceFuelChance);
+		a_Chunk->UnboundedRelSetBlock(
+			a_RelX + gNeighborCoords[i].x, a_RelY + gNeighborCoords[i].y, a_RelZ + gNeighborCoords[i].z,
+			ShouldReplaceFuel ? E_BLOCK_FIRE : E_BLOCK_AIR, 0
+		);
+	}  // for i - Coords[]
 }
 
 
 
 
 
-bool cFireSimulator::BurnBlock(int a_X, int a_Y, int a_Z)
+bool cFireSimulator::CanStartFireInBlock(cChunk * a_NearChunk, int a_RelX, int a_RelY, int a_RelZ)
 {
-	BLOCKTYPE BlockID = m_World.GetBlock(a_X, a_Y, a_Z);
-	if (IsBurnable(BlockID))
+	BLOCKTYPE  BlockType;
+	NIBBLETYPE BlockMeta;
+	if (!a_NearChunk->UnboundedRelGetBlock(a_RelX, a_RelY, a_RelZ, BlockType, BlockMeta))
 	{
-		m_World.SetBlock(a_X, a_Y, a_Z, E_BLOCK_FIRE, 0);
-		return true;
+		// The chunk is not accessible
+		return false;
+	}
+	
+	if (BlockType != E_BLOCK_AIR)
+	{
+		// Only an air block can be replaced by a fire block
+		return false;
 	}
-	if (IsForeverBurnable(BlockID))
+	
+	for (int i = 0; i < ARRAYCOUNT(gNeighborCoords); i++)
 	{
-		BLOCKTYPE BlockAbove = m_World.GetBlock(a_X, a_Y + 1, a_Z);
-		if (BlockAbove == E_BLOCK_AIR)
+		if (!a_NearChunk->UnboundedRelGetBlock(a_RelX + gNeighborCoords[i].x, a_RelY + gNeighborCoords[i].y, a_RelZ + gNeighborCoords[i].z, BlockType, BlockMeta))
+		{
+			// Neighbor inaccessible, skip it while evaluating
+			continue;
+		}
+		if (IsFuel(BlockType))
 		{
-			m_World.SetBlock(a_X, a_Y + 1, a_Z, E_BLOCK_FIRE, 0);	//Doesn´t notify the simulator so it won´t go off
 			return true;
 		}
-		return false;
-	}
-
+	}  // for i - Coords[]
 	return false;
 }
 
diff --git a/source/Simulator/FireSimulator.h b/source/Simulator/FireSimulator.h
index 2a510d276..877075e73 100644
--- a/source/Simulator/FireSimulator.h
+++ b/source/Simulator/FireSimulator.h
@@ -8,31 +8,67 @@
 
 
 
-class cFireSimulator : public cSimulator
+/** The fire simulator takes care of the fire blocks.
+It periodically increases their meta ("steps") until they "burn out"; it also supports the forever burning netherrack.
+Each individual fire block gets stored in per-chunk data; that list is then used for fast retrieval.
+The data value associated with each coord is used as the number of msec that the fire takes until
+it progresses to the next step (blockmeta++). This value is updated if a neighbor is changed.
+The simulator reads its parameters from the ini file given to the constructor.
+*/
+class cFireSimulator :
+	public cSimulator
 {
 public:
-	cFireSimulator(cWorld & a_World);
+	cFireSimulator(cWorld & a_World, cIniFile & a_IniFile);
 	~cFireSimulator();
 
-	virtual void Simulate( float a_Dt ) override;
+	virtual void Simulate(float a_Dt) override {}  // not used
+	virtual void SimulateChunk(float a_Dt, int a_ChunkX, int a_ChunkZ, cChunk * a_Chunk) override;
 
-	virtual bool IsAllowedBlock( BLOCKTYPE a_BlockType ) override;
+	virtual bool IsAllowedBlock(BLOCKTYPE a_BlockType) override;
 
-	virtual bool IsBurnable( BLOCKTYPE a_BlockType );
-	virtual bool IsForeverBurnable( BLOCKTYPE a_BlockType );
-	virtual bool FiresForever( BLOCKTYPE a_BlockType );
+	bool IsFuel   (BLOCKTYPE a_BlockType);
+	bool IsForever(BLOCKTYPE a_BlockType);
 
 protected:
+	/// Time (in msec) that a fire block takes to burn with a fuel block into the next step
+	unsigned m_BurnStepTimeFuel;
+
+	/// Time (in msec) that a fire block takes to burn without a fuel block into the next step
+	unsigned m_BurnStepTimeNonfuel;
+
+	/// Chance [0..100000] of an adjacent fuel to catch fire on each tick
+	unsigned m_Flammability;
+	
+	/// Chance [0..100000] of a fuel burning out being replaced by a new fire block instead of an air block
+	unsigned m_ReplaceFuelChance;
+	
+	
 	virtual void AddBlock(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chunk) override;
-	virtual bool BurnBlockAround(int a_X, int a_Y, int a_Z);
-	virtual bool BurnBlock(int a_X, int a_Y, int a_Z);
-
-	typedef std::list <Vector3i> BlockList;
-	BlockList *m_Blocks;
-	BlockList *m_Buffer;
-
-	BlockList *m_BurningBlocks;
-};
+	
+	/// Returns the time [msec] after which the specified fire block is stepped again; based on surrounding fuels
+	int GetBurnStepTime(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ);
+	
+	/// Tries to spread fire to a neighborhood of the specified block
+	void TrySpreadFire(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ);
+	
+	/// Removes all burnable blocks neighboring the specified block
+	void RemoveFuelNeighbors(cChunk * a_Chunk, int a_RelX, int a_RelY, int a_RelZ);
+	
+	/** Returns true if a fire can be started in the specified block,
+	that is, it is an air block and has fuel next to it.
+	Note that a_NearChunk may be a chunk neighbor to the block specified!
+	The coords are relative to a_NearChunk but not necessarily in it.
+	*/
+	bool CanStartFireInBlock(cChunk * a_NearChunk, int a_RelX, int a_RelY, int a_RelZ);
+} ;
+
+
+
+
+
+/// Stores individual fire blocks in the chunk; the int data is used as the time [msec] the fire takes to step to another stage (blockmeta++)
+typedef cCoordWithIntList cFireSimulatorChunkData;
 
 
 
diff --git a/source/Simulator/Simulator.cpp b/source/Simulator/Simulator.cpp
index 07ed31b52..78e12324a 100644
--- a/source/Simulator/Simulator.cpp
+++ b/source/Simulator/Simulator.cpp
@@ -34,10 +34,10 @@ void cSimulator::WakeUp(int a_BlockX, int a_BlockY, int a_BlockZ, cChunk * a_Chu
 	AddBlock(a_BlockX,     a_BlockY,     a_BlockZ,     a_Chunk);
 	AddBlock(a_BlockX,     a_BlockY - 1, a_BlockZ,     a_Chunk);
 	AddBlock(a_BlockX,     a_BlockY + 1, a_BlockZ,     a_Chunk);
-	AddBlock(a_BlockX - 1, a_BlockY,     a_BlockZ,     a_Chunk->GetNeighborChunk(a_BlockX - 1, a_BlockY, a_BlockZ));
-	AddBlock(a_BlockX + 1, a_BlockY,     a_BlockZ,     a_Chunk->GetNeighborChunk(a_BlockX + 1, a_BlockY, a_BlockZ));
-	AddBlock(a_BlockX,     a_BlockY,     a_BlockZ - 1, a_Chunk->GetNeighborChunk(a_BlockX,     a_BlockY, a_BlockZ - 1));
-	AddBlock(a_BlockX,     a_BlockY,     a_BlockZ + 1, a_Chunk->GetNeighborChunk(a_BlockX,     a_BlockY, a_BlockZ + 1));
+	AddBlock(a_BlockX - 1, a_BlockY,     a_BlockZ,     a_Chunk->GetNeighborChunk(a_BlockX - 1, a_BlockZ));
+	AddBlock(a_BlockX + 1, a_BlockY,     a_BlockZ,     a_Chunk->GetNeighborChunk(a_BlockX + 1, a_BlockZ));
+	AddBlock(a_BlockX,     a_BlockY,     a_BlockZ - 1, a_Chunk->GetNeighborChunk(a_BlockX,     a_BlockZ - 1));
+	AddBlock(a_BlockX,     a_BlockY,     a_BlockZ + 1, a_Chunk->GetNeighborChunk(a_BlockX,     a_BlockZ + 1));
 }
 
 
diff --git a/source/Simulator/Simulator.h b/source/Simulator/Simulator.h
index 1f31bc2e8..63cc0b17f 100644
--- a/source/Simulator/Simulator.h
+++ b/source/Simulator/Simulator.h
@@ -2,6 +2,7 @@
 #pragma once
 
 #include "../Vector3i.h"
+#include "../../iniFile/iniFile.h"
 
 
 
diff --git a/source/World.cpp b/source/World.cpp
index 3097e5029..84874258f 100644
--- a/source/World.cpp
+++ b/source/World.cpp
@@ -254,12 +254,12 @@ cWorld::cWorld(const AString & a_WorldName) :
 	m_WaterSimulator    = InitializeFluidSimulator(IniFile, "Water", E_BLOCK_WATER, E_BLOCK_STATIONARY_WATER);
 	m_LavaSimulator     = InitializeFluidSimulator(IniFile, "Lava",  E_BLOCK_LAVA,  E_BLOCK_STATIONARY_LAVA);
 	m_SandSimulator     = new cSandSimulator(*this);
-	m_FireSimulator     = new cFireSimulator(*this);
+	m_FireSimulator     = new cFireSimulator(*this, IniFile);
 	m_RedstoneSimulator = new cRedstoneSimulator(*this);
 
 	// Water and Lava simulators get registered in InitializeFluidSimulator()
 	m_SimulatorManager->RegisterSimulator(m_SandSimulator, 1);
-	m_SimulatorManager->RegisterSimulator(m_FireSimulator, 10);
+	m_SimulatorManager->RegisterSimulator(m_FireSimulator, 1);
 	m_SimulatorManager->RegisterSimulator(m_RedstoneSimulator, 1);
 
 	// Save any changes that the defaults may have done to the ini file:
diff --git a/source/World.h b/source/World.h
index 6fc3fa088..2965ae1c3 100644
--- a/source/World.h
+++ b/source/World.h
@@ -451,6 +451,9 @@ public:
 	/// Spawns a mob of the specified entity type. Returns the mob's EntityID if recognized and spawned, <0 otherwise
 	int SpawnMob(double a_PosX, double a_PosY, double a_PosZ, int a_EntityType);  // tolua_export
 	
+	/// Returns a random number from the m_TickRand in range [0 .. a_Range]. To be used only in the tick thread!
+	unsigned GetTickRandomNumber(unsigned a_Range) { return m_TickRand.randInt(a_Range); }
+	
 private:
 
 	friend class cRoot;