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diff --git a/src/LightingThread.h b/src/LightingThread.h
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+
+// LightingThread.h
+
+// Interfaces to the cLightingThread class representing the thread that processes requests for lighting
+
+/*
+Lighting is done on whole chunks. For each chunk to be lighted, the whole 3x3 chunk area around it is read,
+then it is processed, so that the middle chunk area has valid lighting, and the lighting is copied into the ChunkMap.
+Lighting is calculated in full char arrays instead of nibbles, so that accessing the arrays is fast.
+Lighting is calculated in a flood-fill fashion:
+1. Generate seeds from where the light spreads (full skylight / light-emitting blocks)
+2. For each seed:
+	- Spread the light 1 block in each of the 6 cardinal directions, if the blocktype allows
+	- If the recipient block has had lower lighting value than that being spread, make it a new seed
+3. Repeat step 2, until there are no more seeds
+The seeds need two fast operations:
+	- Check if a block at [x, y, z] is already a seed
+	- Get the next seed in the row
+For that reason it is stored in two arrays, one stores a bool saying a seed is in that position, 
+the other is an array of seed coords, encoded as a single int.
+Step 2 needs two separate storages for old seeds and new seeds, so there are two actual storages for that purpose,
+their content is swapped after each full step-2-cycle.
+
+The thread has two queues of chunks that are to be lighted.
+The first queue, m_Queue, is the only one that is publicly visible, chunks get queued there by external requests.
+The second one, m_PostponedQueue, is for chunks that have been taken out of m_Queue and didn't have neighbors ready.
+Chunks from m_PostponedQueue are moved back into m_Queue when their neighbors get valid, using the ChunkReady callback.
+*/
+
+
+
+#pragma once
+
+#include "OSSupport/IsThread.h"
+#include "ChunkDef.h"
+
+
+
+
+
+// fwd: "cWorld.h"
+class cWorld;
+
+// fwd: "cChunkMap.h"
+class cChunkStay;
+
+
+
+
+
+class cLightingThread :
+	public cIsThread
+{
+	typedef cIsThread super;
+	
+public:
+	
+	cLightingThread(void);
+	~cLightingThread();
+	
+	bool Start(cWorld * a_World);
+	
+	void Stop(void);
+	
+	/// Queues the entire chunk for lighting
+	void QueueChunk(int a_ChunkX, int a_ChunkZ, cChunkCoordCallback * a_CallbackAfter = NULL);
+	
+	/// Blocks until the queue is empty or the thread is terminated
+	void WaitForQueueEmpty(void);
+	
+	size_t GetQueueLength(void);
+	
+	/// Called from cWorld when a chunk gets valid. Chunks in m_PostponedQueue may need moving into m_Queue
+	void ChunkReady(int a_ChunkX, int a_ChunkZ);
+	
+protected:
+
+	struct sItem
+	{
+		int x, z;
+		cChunkStay * m_ChunkStay;
+		cChunkCoordCallback * m_Callback;
+		
+		sItem(void) {}  // empty default constructor needed
+		sItem(int a_X, int a_Z, cChunkStay * a_ChunkStay, cChunkCoordCallback * a_Callback) :
+			x(a_X),
+			z(a_Z),
+			m_ChunkStay(a_ChunkStay),
+			m_Callback(a_Callback)
+		{
+		}
+	} ;
+	
+	typedef std::list<sItem> sItems;
+	
+	cWorld *         m_World;
+	cCriticalSection m_CS;
+	sItems           m_Queue;
+	sItems           m_PostponedQueue;  // Chunks that have been postponed due to missing neighbors
+	cEvent           m_evtItemAdded;    // Set when queue is appended, or to stop the thread
+	cEvent           m_evtQueueEmpty;   // Set when the queue gets empty
+	
+	// Buffers for the 3x3 chunk data
+	// These buffers alone are 1.7 MiB in size, therefore they cannot be located on the stack safely - some architectures may have only 1 MiB for stack, or even less
+	// Placing the buffers into the object means that this object can light chunks only in one thread!
+	// The blobs are XZY organized as a whole, instead of 3x3 XZY-organized subarrays ->
+	//  -> This means data has to be scatterred when reading and gathered when writing!
+	static const int BlocksPerYLayer = cChunkDef::Width * cChunkDef::Width * 3 * 3;
+	BLOCKTYPE  m_BlockTypes[BlocksPerYLayer * cChunkDef::Height];
+	NIBBLETYPE m_BlockLight[BlocksPerYLayer * cChunkDef::Height];
+	NIBBLETYPE m_SkyLight  [BlocksPerYLayer * cChunkDef::Height];
+	HEIGHTTYPE m_HeightMap [BlocksPerYLayer];
+	
+	// Seed management (5.7 MiB)
+	// Two buffers, in each calc step one is set as input and the other as output, then in the next step they're swapped
+	// Each seed is represented twice in this structure - both as a "list" and as a "position".
+	// "list" allows fast traversal from seed to seed
+	// "position" allows fast checking if a coord is already a seed
+	unsigned char m_IsSeed1 [BlocksPerYLayer * cChunkDef::Height];
+	unsigned int  m_SeedIdx1[BlocksPerYLayer * cChunkDef::Height];
+	unsigned char m_IsSeed2 [BlocksPerYLayer * cChunkDef::Height];
+	unsigned int  m_SeedIdx2[BlocksPerYLayer * cChunkDef::Height];
+	int m_NumSeeds;
+
+	virtual void Execute(void) override;
+
+	/// Lights the entire chunk. If neighbor chunks don't exist, touches them and re-queues the chunk
+	void LightChunk(sItem & a_Item);
+	
+	/// Prepares m_BlockTypes and m_HeightMap data; returns false if any of the chunks fail. Zeroes out the light arrays
+	bool ReadChunks(int a_ChunkX, int a_ChunkZ);
+	
+	/// Uses m_HeightMap to initialize the m_SkyLight[] data; fills in seeds for the skylight
+	void PrepareSkyLight(void);
+	
+	/// Uses m_BlockTypes to initialize the m_BlockLight[] data; fills in seeds for the blocklight
+	void PrepareBlockLight(void);
+	
+	/// Calculates light in the light array specified, using stored seeds
+	void CalcLight(NIBBLETYPE * a_Light);
+	
+	/// Does one step in the light calculation - one seed propagation and seed recalculation
+	void CalcLightStep(
+		NIBBLETYPE * a_Light, 
+		int a_NumSeedsIn,    unsigned char * a_IsSeedIn,  unsigned int * a_SeedIdxIn,
+		int & a_NumSeedsOut, unsigned char * a_IsSeedOut, unsigned int * a_SeedIdxOut
+	);
+	
+	/// Compresses from 1-block-per-byte (faster calc) into 2-blocks-per-byte (MC storage):
+	void CompressLight(NIBBLETYPE * a_LightArray, NIBBLETYPE * a_ChunkLight);
+	
+	inline void PropagateLight(
+		NIBBLETYPE * a_Light, 
+		int a_SrcIdx, int a_DstIdx,
+		int & a_NumSeedsOut, unsigned char * a_IsSeedOut, unsigned int * a_SeedIdxOut
+	)
+	{
+		ASSERT(a_SrcIdx >= 0);
+		ASSERT(a_SrcIdx < ARRAYCOUNT(m_SkyLight));
+		ASSERT(a_DstIdx >= 0);
+		ASSERT(a_DstIdx < ARRAYCOUNT(m_BlockTypes));
+		
+		if (a_Light[a_SrcIdx] <= a_Light[a_DstIdx] + g_BlockSpreadLightFalloff[m_BlockTypes[a_DstIdx]])
+		{
+			// We're not offering more light than the dest block already has
+			return;
+		}
+
+		a_Light[a_DstIdx] = a_Light[a_SrcIdx] - g_BlockSpreadLightFalloff[m_BlockTypes[a_DstIdx]];
+		if (!a_IsSeedOut[a_DstIdx])
+		{
+			a_IsSeedOut[a_DstIdx] = true;
+			a_SeedIdxOut[a_NumSeedsOut++] = a_DstIdx;
+		}
+	}
+	
+} ;
+
+
+
+