30 files changed, 1578 insertions, 1532 deletions

diff --git a/src/Generating/CMakeLists.txt b/src/Generating/CMakeLists.txt
index 1a26bd0d5..a28510d40 100644
--- a/src/Generating/CMakeLists.txt
+++ b/src/Generating/CMakeLists.txt
@@ -10,6 +10,7 @@ SET (SRCS
 	ChunkDesc.cpp
 	ChunkGenerator.cpp
 	CompoGen.cpp
+	CompoGenBiomal.cpp
 	ComposableGenerator.cpp
 	DistortedHeightmap.cpp
 	DungeonRoomsFinisher.cpp
@@ -30,8 +31,10 @@ SET (SRCS
 	StructGen.cpp
 	TestRailsGen.cpp
 	Trees.cpp
+	TwoHeights.cpp
 	UnderwaterBaseGen.cpp
-	VillageGen.cpp)
+	VillageGen.cpp
+)
 
 SET (HDRS
 	BioGen.h
@@ -39,7 +42,9 @@ SET (HDRS
 	ChunkDesc.h
 	ChunkGenerator.h
 	CompoGen.h
+	CompoGenBiomal.h
 	ComposableGenerator.h
+	CompositedHeiGen.h
 	DistortedHeightmap.h
 	DungeonRoomsFinisher.h
 	EndGen.h
@@ -58,11 +63,14 @@ SET (HDRS
 	RainbowRoadsGen.h
 	Ravines.h
 	RoughRavines.h
+	ShapeGen.cpp
 	StructGen.h
 	TestRailsGen.h
 	Trees.h
+	TwoHeights.h
 	UnderwaterBaseGen.h
-	VillageGen.h)
+	VillageGen.h
+)
 
 if(NOT MSVC)
 	add_library(Generating ${SRCS} ${HDRS})
diff --git a/src/Generating/ChunkDesc.cpp b/src/Generating/ChunkDesc.cpp
index 042b688b7..4a5ac5a18 100644
--- a/src/Generating/ChunkDesc.cpp
+++ b/src/Generating/ChunkDesc.cpp
@@ -152,6 +152,52 @@ int cChunkDesc::GetHeight(int a_RelX, int a_RelZ)
 
 
 
+void cChunkDesc::SetHeightFromShape(const Shape & a_Shape)
+{
+	for (int z = 0; z < cChunkDef::Width; z++)
+	{
+		for (int x = 0; x < cChunkDef::Width; x++)
+		{
+			for (int y = cChunkDef::Height - 1; y > 0; y--)
+			{
+				if (a_Shape[y + x * 256 + z * 16 * 256] != 0)
+				{
+					cChunkDef::SetHeight(m_HeightMap, x, z, y);
+					break;
+				}
+			}  // for y
+		}  // for x
+	}  // for z
+}
+
+
+
+
+
+void cChunkDesc::GetShapeFromHeight(Shape & a_Shape) const
+{
+	for (int z = 0; z < cChunkDef::Width; z++)
+	{
+		for (int x = 0; x < cChunkDef::Width; x++)
+		{
+			int height = cChunkDef::GetHeight(m_HeightMap, x, z);
+			for (int y = 0; y <= height; y++)
+			{
+				a_Shape[y + x * 256 + z * 16 * 256] = 1;
+			}
+			
+			for (int y = height + 1; y < cChunkDef::Height; y++)
+			{
+				a_Shape[y + x * 256 + z * 16 * 256] = 0;
+			}  // for y
+		}  // for x
+	}  // for z
+}
+
+
+
+
+
 void cChunkDesc::SetUseDefaultBiomes(bool a_bUseDefaultBiomes)
 {
 	m_bUseDefaultBiomes = a_bUseDefaultBiomes;
@@ -366,6 +412,23 @@ HEIGHTTYPE cChunkDesc::GetMaxHeight(void) const
 
 
 
+HEIGHTTYPE cChunkDesc::GetMinHeight(void) const
+{
+	HEIGHTTYPE MinHeight = m_HeightMap[0];
+	for (size_t i = 1; i < ARRAYCOUNT(m_HeightMap); i++)
+	{
+		if (m_HeightMap[i] < MinHeight)
+		{
+			MinHeight = m_HeightMap[i];
+		}
+	}
+	return MinHeight;
+}
+
+
+
+
+
 void cChunkDesc::FillRelCuboid(
 	int a_MinX, int a_MaxX,
 	int a_MinY, int a_MaxY,
diff --git a/src/Generating/ChunkDesc.h b/src/Generating/ChunkDesc.h
index 570132790..480106fb5 100644
--- a/src/Generating/ChunkDesc.h
+++ b/src/Generating/ChunkDesc.h
@@ -29,10 +29,17 @@ class cChunkDesc
 {
 public:
 	// tolua_end
+
+	/** The datatype used to represent the entire chunk worth of shape.
+	0 = air
+	1 = solid
+	Indexed as [y + 256 * x + 256 * 16 * z]. */
+	typedef Byte Shape[256 * 16 * 16];
 	
 	/** Uncompressed block metas, 1 meta per byte */
 	typedef NIBBLETYPE BlockNibbleBytes[cChunkDef::NumBlocks];
 	
+
 	cChunkDesc(int a_ChunkX, int a_ChunkZ);
 	~cChunkDesc();
 
@@ -57,10 +64,21 @@ public:
 	EMCSBiome  GetBiome(int a_RelX, int a_RelZ);
 
 	// These operate on the heightmap, so they could get out of sync with the data
-	// Use UpdateHeightmap() to re-sync
+	// Use UpdateHeightmap() to re-calculate heightmap from the block data
 	void       SetHeight(int a_RelX, int a_RelZ, int a_Height);
 	int        GetHeight(int a_RelX, int a_RelZ);
 
+	// tolua_end
+
+	/** Sets the heightmap to match the given shape data.
+	Note that this ignores overhangs; the method is mostly used by old composition generators. */
+	void SetHeightFromShape(const Shape & a_Shape);
+
+	/** Sets the shape in a_Shape to match the heightmap stored currently in m_HeightMap. */
+	void GetShapeFromHeight(Shape & a_Shape) const;
+
+	// tolua_begin
+
 	// Default generation:
 	void SetUseDefaultBiomes(bool a_bUseDefaultBiomes);
 	bool IsUsingDefaultBiomes(void) const;
@@ -77,8 +95,11 @@ public:
 	/** Reads an area from the chunk into a cBlockArea, blocktypes and blockmetas */
 	void ReadBlockArea(cBlockArea & a_Dest, int a_MinRelX, int a_MaxRelX, int a_MinRelY, int a_MaxRelY, int a_MinRelZ, int a_MaxRelZ);
 
-	/** Returns the maximum height value in the heightmap */
+	/** Returns the maximum height value in the heightmap. */
 	HEIGHTTYPE GetMaxHeight(void) const;
+
+	/** Returns the minimum height value in the heightmap. */
+	HEIGHTTYPE GetMinHeight(void) const;
 	
 	/** Fills the relative cuboid with specified block; allows cuboid out of range of this chunk */
 	void FillRelCuboid(
diff --git a/src/Generating/CompoGen.cpp b/src/Generating/CompoGen.cpp
index 29b831dfd..23cc64d78 100644
--- a/src/Generating/CompoGen.cpp
+++ b/src/Generating/CompoGen.cpp
@@ -21,8 +21,9 @@
 ////////////////////////////////////////////////////////////////////////////////
 // cCompoGenSameBlock:
 
-void cCompoGenSameBlock::ComposeTerrain(cChunkDesc & a_ChunkDesc)
+void cCompoGenSameBlock::ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape)
 {
+	a_ChunkDesc.SetHeightFromShape(a_Shape);
 	a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
 	for (int z = 0; z < cChunkDef::Width; z++)
 	{
@@ -63,7 +64,7 @@ void cCompoGenSameBlock::InitializeCompoGen(cIniFile & a_IniFile)
 ////////////////////////////////////////////////////////////////////////////////
 // cCompoGenDebugBiomes:
 
-void cCompoGenDebugBiomes::ComposeTerrain(cChunkDesc & a_ChunkDesc)
+void cCompoGenDebugBiomes::ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape)
 {
 	static BLOCKTYPE Blocks[] =
 	{
@@ -92,6 +93,7 @@ void cCompoGenDebugBiomes::ComposeTerrain(cChunkDesc & a_ChunkDesc)
 		E_BLOCK_BEDROCK,
 	} ;
 	
+	a_ChunkDesc.SetHeightFromShape(a_Shape);
 	a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
 
 	for (int z = 0; z < cChunkDef::Width; z++)
@@ -131,7 +133,7 @@ cCompoGenClassic::cCompoGenClassic(void) :
 
 
 
-void cCompoGenClassic::ComposeTerrain(cChunkDesc & a_ChunkDesc)
+void cCompoGenClassic::ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape)
 {
 	/* The classic composition means:
 		- 1 layer of grass, 3 of dirt and the rest stone, if the height > sealevel + beachheight
@@ -142,6 +144,7 @@ void cCompoGenClassic::ComposeTerrain(cChunkDesc & a_ChunkDesc)
 	*/
 
 	a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
+	a_ChunkDesc.SetHeightFromShape(a_Shape);
 
 	// The patterns to use for different situations, must be same length!
 	const BLOCKTYPE PatternGround[] = {m_BlockTop,    m_BlockMiddle, m_BlockMiddle, m_BlockMiddle} ;
@@ -194,7 +197,7 @@ void cCompoGenClassic::ComposeTerrain(cChunkDesc & a_ChunkDesc)
 
 void cCompoGenClassic::InitializeCompoGen(cIniFile & a_IniFile)
 {
-	m_SeaLevel         = a_IniFile.GetValueSetI("Generator", "ClassicSeaLevel",    m_SeaLevel);
+	m_SeaLevel         = a_IniFile.GetValueSetI("Generator", "SeaLevel",           m_SeaLevel);
 	m_BeachHeight      = a_IniFile.GetValueSetI("Generator", "ClassicBeachHeight", m_BeachHeight);
 	m_BeachDepth       = a_IniFile.GetValueSetI("Generator", "ClassicBeachDepth",  m_BeachDepth);
 	m_BlockTop         = (BLOCKTYPE)(GetIniItemSet(a_IniFile, "Generator", "ClassicBlockTop",         "grass").m_ItemType);
@@ -210,323 +213,6 @@ void cCompoGenClassic::InitializeCompoGen(cIniFile & a_IniFile)
 
 
 ////////////////////////////////////////////////////////////////////////////////
-// cCompoGenBiomal:
-
-void cCompoGenBiomal::ComposeTerrain(cChunkDesc & a_ChunkDesc)
-{
-	a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
-
-	int ChunkX = a_ChunkDesc.GetChunkX();
-	int ChunkZ = a_ChunkDesc.GetChunkZ();
-	
-	/*
-	_X 2013_04_22:
-	There's no point in generating the whole cubic noise at once, because the noise values are used in
-	only about 20 % of the cases, so the speed gained by precalculating is lost by precalculating too much data
-	*/
-	
-	for (int z = 0; z < cChunkDef::Width; z++)
-	{
-		for (int x = 0; x < cChunkDef::Width; x++)
-		{
-			int Height = a_ChunkDesc.GetHeight(x, z);
-			if (Height > m_SeaLevel)
-			{
-				switch (a_ChunkDesc.GetBiome(x, z))
-				{
-					case biOcean:
-					case biPlains:
-					case biExtremeHills:
-					case biForest:
-					case biTaiga:
-					case biSwampland:
-					case biRiver:
-					case biFrozenOcean:
-					case biFrozenRiver:
-					case biIcePlains:
-					case biIceMountains:
-					case biForestHills:
-					case biTaigaHills:
-					case biExtremeHillsEdge:
-					case biJungle:
-					case biJungleHills:
-					case biJungleEdge:
-					case biDeepOcean:
-					case biStoneBeach:
-					case biColdBeach:
-					case biBirchForest:
-					case biBirchForestHills:
-					case biRoofedForest:
-					case biColdTaiga:
-					case biColdTaigaHills:
-					case biExtremeHillsPlus:
-					case biSavanna:
-					case biSavannaPlateau:
-					case biSunflowerPlains:
-					case biExtremeHillsM:
-					case biFlowerForest:
-					case biTaigaM:
-					case biSwamplandM:
-					case biIcePlainsSpikes:
-					case biJungleM:
-					case biJungleEdgeM:
-					case biBirchForestM:
-					case biBirchForestHillsM:
-					case biRoofedForestM:
-					case biColdTaigaM:
-					case biExtremeHillsPlusM:
-					case biSavannaM:
-					case biSavannaPlateauM:
-					{
-						FillColumnGrass(x, z, Height, a_ChunkDesc.GetBlockTypes());
-						break;
-					}
-
-					case biMesa:
-					case biMesaPlateauF:
-					case biMesaPlateau:
-					case biMesaBryce:
-					case biMesaPlateauFM:
-					case biMesaPlateauM:
-					{
-						FillColumnClay(x, z, Height, a_ChunkDesc.GetBlockTypes());
-						break;
-					}
-					
-					case biMegaTaiga:
-					case biMegaTaigaHills:
-					case biMegaSpruceTaiga:
-					case biMegaSpruceTaigaHills:
-					{
-						FillColumnDirt(x, z, Height, a_ChunkDesc.GetBlockTypes());
-						break;
-					}
-
-					case biDesertHills:
-					case biDesert:
-					case biDesertM:
-					case biBeach:
-					{
-						FillColumnSand(x, z, Height, a_ChunkDesc.GetBlockTypes());
-						break;
-					}
-					case biMushroomIsland:
-					case biMushroomShore:
-					{
-						FillColumnMycelium(x, z, Height, a_ChunkDesc.GetBlockTypes());
-						break;
-					}
-					default:
-					{
-						// TODO
-						ASSERT(!"CompoGenBiomal: Biome not implemented yet!");
-						break;
-					}
-				}
-			}
-			else
-			{
-				switch (a_ChunkDesc.GetBiome(x, z))
-				{
-					case biDesert:
-					case biBeach:
-					{
-						// Fill with water, sand, sandstone and stone
-						FillColumnWaterSand(x, z, Height, a_ChunkDesc.GetBlockTypes());
-						break;
-					}
-					default:
-					{
-						// Fill with water, sand/dirt/clay mix and stone
-						if (m_Noise.CubicNoise2D(0.3f * (cChunkDef::Width * ChunkX + x), 0.3f * (cChunkDef::Width * ChunkZ + z)) < 0)
-						{
-							FillColumnWaterSand(x, z, Height, a_ChunkDesc.GetBlockTypes());
-						}
-						else
-						{
-							FillColumnWaterDirt(x, z, Height, a_ChunkDesc.GetBlockTypes());
-						}
-						break;
-					}
-				}  // switch (biome)
-				a_ChunkDesc.SetHeight(x, z, m_SeaLevel + 1);
-			}  // else (under water)
-			a_ChunkDesc.SetBlockType(x, 0, z, E_BLOCK_BEDROCK);
-		}  // for x
-	}  // for z
-}
-
-
-
-
-
-void cCompoGenBiomal::InitializeCompoGen(cIniFile & a_IniFile)
-{
-	m_SeaLevel = a_IniFile.GetValueSetI("Generator", "BiomalSeaLevel", m_SeaLevel) - 1;
-}
-
-
-
-
-
-void cCompoGenBiomal::FillColumnGrass(int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes)
-{
-	BLOCKTYPE Pattern[] =
-	{
-		E_BLOCK_GRASS,
-		E_BLOCK_DIRT,
-		E_BLOCK_DIRT,
-		E_BLOCK_DIRT,
-	} ;
-	FillColumnPattern(a_RelX, a_RelZ, a_Height, a_BlockTypes, Pattern, ARRAYCOUNT(Pattern));
-	
-	for (int y = a_Height - ARRAYCOUNT(Pattern); y > 0; y--)
-	{
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, y, a_RelZ, E_BLOCK_STONE);
-	}
-}
-
-
-
-
-
-void cCompoGenBiomal::FillColumnClay(int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes)
-{
-	BLOCKTYPE Pattern[] =
-	{
-		E_BLOCK_HARDENED_CLAY,
-		E_BLOCK_HARDENED_CLAY,
-		E_BLOCK_HARDENED_CLAY,
-		E_BLOCK_HARDENED_CLAY,
-	} ;
-	FillColumnPattern(a_RelX, a_RelZ, a_Height, a_BlockTypes, Pattern, ARRAYCOUNT(Pattern));
-	
-	for (int y = a_Height - ARRAYCOUNT(Pattern); y > 0; y--)
-	{
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, y, a_RelZ, E_BLOCK_STONE);
-	}
-}
-
-
-
-
-
-void cCompoGenBiomal::FillColumnDirt(int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes)
-{
-	for (int y = 0; y < 4; y++)
-	{
-		if (a_Height - y < 0)
-		{
-			return;
-		}
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, a_Height - y, a_RelZ, E_BLOCK_DIRT);
-	}
-	for (int y = a_Height - 4; y > 0; y--)
-	{
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, y, a_RelZ, E_BLOCK_STONE);
-	}
-}
-
-
-
-
-
-void cCompoGenBiomal::FillColumnSand(int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes)
-{
-	BLOCKTYPE Pattern[] =
-	{
-		E_BLOCK_SAND,
-		E_BLOCK_SAND,
-		E_BLOCK_SAND,
-		E_BLOCK_SANDSTONE,
-	} ;
-	FillColumnPattern(a_RelX, a_RelZ, a_Height, a_BlockTypes, Pattern, ARRAYCOUNT(Pattern));
-	
-	for (int y = a_Height - ARRAYCOUNT(Pattern); y > 0; y--)
-	{
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, y, a_RelZ, E_BLOCK_STONE);
-	}
-}
-
-
-
-
-
-
-void cCompoGenBiomal::FillColumnMycelium (int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes)
-{
-	BLOCKTYPE Pattern[] =
-	{
-		E_BLOCK_MYCELIUM,
-		E_BLOCK_DIRT,
-		E_BLOCK_DIRT,
-		E_BLOCK_DIRT,
-	} ;
-	FillColumnPattern(a_RelX, a_RelZ, a_Height, a_BlockTypes, Pattern, ARRAYCOUNT(Pattern));
-	
-	for (int y = a_Height - ARRAYCOUNT(Pattern); y > 0; y--)
-	{
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, y, a_RelZ, E_BLOCK_STONE);
-	}
-}
-
-
-
-
-
-void cCompoGenBiomal::FillColumnWaterSand(int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes)
-{
-	FillColumnSand(a_RelX, a_RelZ, a_Height, a_BlockTypes);
-	for (int y = a_Height + 1; y <= m_SeaLevel + 1; y++)
-	{
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, y, a_RelZ, E_BLOCK_STATIONARY_WATER);
-	}
-}
-
-
-
-
-
-void cCompoGenBiomal::FillColumnWaterDirt(int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes)
-{
-	// Dirt
-	BLOCKTYPE Pattern[] =
-	{
-		E_BLOCK_DIRT,
-		E_BLOCK_DIRT,
-		E_BLOCK_DIRT,
-		E_BLOCK_DIRT,
-	} ;
-	FillColumnPattern(a_RelX, a_RelZ, a_Height, a_BlockTypes, Pattern, ARRAYCOUNT(Pattern));
-
-	for (int y = a_Height - ARRAYCOUNT(Pattern); y > 0; y--)
-	{
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, y, a_RelZ, E_BLOCK_STONE);
-	}
-	for (int y = a_Height + 1; y <= m_SeaLevel + 1; y++)
-	{
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, y, a_RelZ, E_BLOCK_STATIONARY_WATER);
-	}
-}
-
-
-
-
-
-
-void cCompoGenBiomal::FillColumnPattern(int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes, const BLOCKTYPE * a_Pattern, int a_PatternSize)
-{
-	for (int y = a_Height, idx = 0; (y >= 0) && (idx < a_PatternSize); y--, idx++)
-	{
-		cChunkDef::SetBlock(a_BlockTypes, a_RelX, y, a_RelZ, a_Pattern[idx]);
-	}
-}
-
-
-
-
-
-////////////////////////////////////////////////////////////////////////////////
 // cCompoGenNether:
 
 cCompoGenNether::cCompoGenNether(int a_Seed) :
@@ -540,7 +226,7 @@ cCompoGenNether::cCompoGenNether(int a_Seed) :
 
 
 
-void cCompoGenNether::ComposeTerrain(cChunkDesc & a_ChunkDesc)
+void cCompoGenNether::ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape)
 {
 	HEIGHTTYPE MaxHeight = a_ChunkDesc.GetMaxHeight();
 	
@@ -696,7 +382,7 @@ cCompoGenCache::~cCompoGenCache()
 
 
 
-void cCompoGenCache::ComposeTerrain(cChunkDesc & a_ChunkDesc)
+void cCompoGenCache::ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape)
 {
 	#ifdef _DEBUG
 	if (((m_NumHits + m_NumMisses) % 1024) == 10)
@@ -731,6 +417,7 @@ void cCompoGenCache::ComposeTerrain(cChunkDesc & a_ChunkDesc)
 		// Use the cached data:
 		memcpy(a_ChunkDesc.GetBlockTypes(),             m_CacheData[Idx].m_BlockTypes, sizeof(a_ChunkDesc.GetBlockTypes()));
 		memcpy(a_ChunkDesc.GetBlockMetasUncompressed(), m_CacheData[Idx].m_BlockMetas, sizeof(a_ChunkDesc.GetBlockMetasUncompressed()));
+		memcpy(a_ChunkDesc.GetHeightMap(),              m_CacheData[Idx].m_HeightMap,  sizeof(a_ChunkDesc.GetHeightMap()));
 		
 		m_NumHits++;
 		m_TotalChain += i;
@@ -739,7 +426,7 @@ void cCompoGenCache::ComposeTerrain(cChunkDesc & a_ChunkDesc)
 	
 	// Not in the cache:
 	m_NumMisses++;
-	m_Underlying->ComposeTerrain(a_ChunkDesc);
+	m_Underlying->ComposeTerrain(a_ChunkDesc, a_Shape);
 	
 	// Insert it as the first item in the MRU order:
 	int Idx = m_CacheOrder[m_CacheSize - 1];
@@ -750,6 +437,7 @@ void cCompoGenCache::ComposeTerrain(cChunkDesc & a_ChunkDesc)
 	m_CacheOrder[0] = Idx;
 	memcpy(m_CacheData[Idx].m_BlockTypes, a_ChunkDesc.GetBlockTypes(),             sizeof(a_ChunkDesc.GetBlockTypes()));
 	memcpy(m_CacheData[Idx].m_BlockMetas, a_ChunkDesc.GetBlockMetasUncompressed(), sizeof(a_ChunkDesc.GetBlockMetasUncompressed()));
+	memcpy(m_CacheData[Idx].m_HeightMap,  a_ChunkDesc.GetHeightMap(),              sizeof(a_ChunkDesc.GetHeightMap()));
 	m_CacheData[Idx].m_ChunkX = ChunkX;
 	m_CacheData[Idx].m_ChunkZ = ChunkZ;
 }
diff --git a/src/Generating/CompoGen.h b/src/Generating/CompoGen.h
index c65a07fe8..3847688cd 100644
--- a/src/Generating/CompoGen.h
+++ b/src/Generating/CompoGen.h
@@ -38,7 +38,7 @@ protected:
 	bool      m_IsBedrocked;
 	
 	// cTerrainCompositionGen overrides:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
+	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape) override;
 	virtual void InitializeCompoGen(cIniFile & a_IniFile) override;
 } ;
 
@@ -55,7 +55,7 @@ public:
 protected:
 	
 	// cTerrainCompositionGen overrides:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
+	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape) override;
 } ;
 
 
@@ -81,7 +81,7 @@ protected:
 	BLOCKTYPE m_BlockSea;
 	
 	// cTerrainCompositionGen overrides:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
+	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape) override;
 	virtual void InitializeCompoGen(cIniFile & a_IniFile) override;
 } ;
 
@@ -89,40 +89,6 @@ protected:
 
 
 
-class cCompoGenBiomal :
-	public cTerrainCompositionGen
-{
-public:
-	cCompoGenBiomal(int a_Seed) :
-		m_Noise(a_Seed + 1000),
-		m_SeaLevel(62)
-	{
-	}
-	
-protected:
-
-	cNoise m_Noise;
-	int    m_SeaLevel;
-	
-	// cTerrainCompositionGen overrides:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
-	virtual void InitializeCompoGen(cIniFile & a_IniFile) override;
-	
-	void FillColumnGrass    (int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes);
-	void FillColumnClay     (int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes);
-	void FillColumnDirt     (int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes);
-	void FillColumnSand     (int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes);
-	void FillColumnMycelium (int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes);
-	void FillColumnWaterSand(int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes);
-	void FillColumnWaterDirt(int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes);
-	
-	void FillColumnPattern  (int a_RelX, int a_RelZ, int a_Height, cChunkDef::BlockTypes & a_BlockTypes, const BLOCKTYPE * a_Pattern, int a_PatternSize);
-} ;
-
-
-
-
-
 class cCompoGenNether :
 	public cTerrainCompositionGen
 {
@@ -136,7 +102,7 @@ protected:
 	int m_Threshold;
 	
 	// cTerrainCompositionGen overrides:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
+	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape) override;
 	virtual void InitializeCompoGen(cIniFile & a_IniFile) override;
 } ;
 
@@ -153,7 +119,7 @@ public:
 	~cCompoGenCache();
 	
 	// cTerrainCompositionGen override:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
+	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape) override;
 	virtual void InitializeCompoGen(cIniFile & a_IniFile) override;
 	
 protected:
@@ -166,6 +132,7 @@ protected:
 		int m_ChunkZ;
 		cChunkDef::BlockTypes        m_BlockTypes;
 		cChunkDesc::BlockNibbleBytes m_BlockMetas;  // The metas are uncompressed, 1 meta per byte
+		cChunkDef::HeightMap         m_HeightMap;
 	} ;
 	
 	// To avoid moving large amounts of data for the MRU behavior, we MRU-ize indices to an array of the actual data
diff --git a/src/Generating/CompoGenBiomal.cpp b/src/Generating/CompoGenBiomal.cpp
new file mode 100644
index 000000000..995851c95
--- /dev/null
+++ b/src/Generating/CompoGenBiomal.cpp
@@ -0,0 +1,586 @@
+
+// CompoGenBiomal.cpp
+
+// Implements the cCompoGenBiomal class representing the biome-aware composition generator
+
+#include "Globals.h"
+#include "ComposableGenerator.h"
+#include "../IniFile.h"
+#include "../Noise/Noise.h"
+#include "../LinearUpscale.h"
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// cPattern:
+
+/** This class is used to store a column pattern initialized at runtime,
+so that the program doesn't need to explicitly set 256 values for each pattern
+Each pattern has 256 blocks so that there's no need to check pattern bounds when assigning the
+pattern - there will always be enough pattern left, even for the whole-chunk-height columns. */
+class cPattern
+{
+public:
+	struct BlockInfo
+	{
+		BLOCKTYPE  m_BlockType;
+		NIBBLETYPE m_BlockMeta;
+	};
+
+	cPattern(BlockInfo * a_TopBlocks, size_t a_Count)
+	{
+		// Copy the pattern into the top:
+		for (size_t i = 0; i < a_Count; i++)
+		{
+			m_Pattern[i] = a_TopBlocks[i];
+		}
+		
+		// Fill the rest with stone:
+		static BlockInfo Stone = {E_BLOCK_STONE, 0};
+		for (size_t i = a_Count; i < cChunkDef::Height; i++)
+		{
+			m_Pattern[i] = Stone;
+		}
+	}
+	
+	const BlockInfo * Get(void) const { return m_Pattern; }
+	
+protected:
+	BlockInfo m_Pattern[cChunkDef::Height];
+} ;
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// The arrays to use for the top block pattern definitions:
+
+static cPattern::BlockInfo tbGrass[] =
+{
+	{E_BLOCK_GRASS, 0},
+	{E_BLOCK_DIRT,  E_META_DIRT_NORMAL},
+	{E_BLOCK_DIRT,  E_META_DIRT_NORMAL},
+	{E_BLOCK_DIRT,  E_META_DIRT_NORMAL},
+} ;
+
+static cPattern::BlockInfo tbSand[] =
+{
+	{ E_BLOCK_SAND, 0},
+	{ E_BLOCK_SAND, 0},
+	{ E_BLOCK_SAND, 0},
+	{ E_BLOCK_SANDSTONE, 0},
+} ;
+
+static cPattern::BlockInfo tbDirt[] =
+{
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+} ;
+
+static cPattern::BlockInfo tbPodzol[] =
+{
+	{E_BLOCK_DIRT, E_META_DIRT_PODZOL},
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+} ;
+
+static cPattern::BlockInfo tbGrassLess[] =
+{
+	{E_BLOCK_DIRT, E_META_DIRT_GRASSLESS},
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
+} ;
+
+static cPattern::BlockInfo tbMycelium[] =
+{
+	{E_BLOCK_MYCELIUM, 0},
+	{E_BLOCK_DIRT,     0},
+	{E_BLOCK_DIRT,     0},
+	{E_BLOCK_DIRT,     0},
+} ;
+
+static cPattern::BlockInfo tbGravel[] =
+{
+	{E_BLOCK_GRAVEL, 0},
+	{E_BLOCK_GRAVEL, 0},
+	{E_BLOCK_GRAVEL, 0},
+	{E_BLOCK_STONE,  0},
+} ;
+
+static cPattern::BlockInfo tbStone[] =
+{
+	{E_BLOCK_STONE,   0},
+	{E_BLOCK_STONE,   0},
+	{E_BLOCK_STONE,   0},
+	{E_BLOCK_STONE,   0},
+} ;
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Ocean floor pattern top-block definitions:
+
+static cPattern::BlockInfo tbOFSand[] =
+{
+	{E_BLOCK_SAND, 0},
+	{E_BLOCK_SAND, 0},
+	{E_BLOCK_SAND, 0},
+	{E_BLOCK_SANDSTONE, 0}
+} ;
+
+static cPattern::BlockInfo tbOFClay[] =
+{
+	{ E_BLOCK_CLAY, 0},
+	{ E_BLOCK_CLAY, 0},
+	{ E_BLOCK_SAND, 0},
+	{ E_BLOCK_SAND, 0},
+} ;
+
+static cPattern::BlockInfo tbOFOrangeClay[] =
+{
+	{ E_BLOCK_STAINED_CLAY, E_META_STAINED_GLASS_ORANGE},
+	{ E_BLOCK_STAINED_CLAY, E_META_STAINED_GLASS_ORANGE},
+	{ E_BLOCK_STAINED_CLAY, E_META_STAINED_GLASS_ORANGE},
+} ;
+
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Individual patterns to use:
+
+static cPattern patGrass    (tbGrass,     ARRAYCOUNT(tbGrass));
+static cPattern patSand     (tbSand,      ARRAYCOUNT(tbSand));
+static cPattern patDirt     (tbDirt,      ARRAYCOUNT(tbDirt));
+static cPattern patPodzol   (tbPodzol,    ARRAYCOUNT(tbPodzol));
+static cPattern patGrassLess(tbGrassLess, ARRAYCOUNT(tbGrassLess));
+static cPattern patMycelium (tbMycelium,  ARRAYCOUNT(tbMycelium));
+static cPattern patGravel   (tbGravel,    ARRAYCOUNT(tbGravel));
+static cPattern patStone    (tbStone,     ARRAYCOUNT(tbStone));
+
+static cPattern patOFSand      (tbOFSand,       ARRAYCOUNT(tbOFSand));
+static cPattern patOFClay      (tbOFClay,       ARRAYCOUNT(tbOFClay));
+static cPattern patOFOrangeClay(tbOFOrangeClay, ARRAYCOUNT(tbOFOrangeClay));
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// cCompoGenBiomal:
+
+class cCompoGenBiomal :
+	public cTerrainCompositionGen
+{
+public:
+	cCompoGenBiomal(int a_Seed) :
+		m_SeaLevel(62),
+		m_OceanFloorSelect(a_Seed + 1),
+		m_MesaFloor(a_Seed + 2)
+	{
+		initMesaPattern(a_Seed);
+	}
+	
+protected:
+	/** The block height at which water is generated instead of air. */
+	int m_SeaLevel;
+
+	/** The pattern used for mesa biomes. Initialized by seed on generator creation. */
+	cPattern::BlockInfo m_MesaPattern[2 * cChunkDef::Height];
+	
+	/** Noise used for selecting between dirt and sand on the ocean floor. */
+	cNoise m_OceanFloorSelect;
+
+	/** Noise used for the floor of the clay blocks in mesa biomes. */
+	cNoise m_MesaFloor;
+
+
+	// cTerrainCompositionGen overrides:
+	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape) override
+	{
+		a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
+		for (int z = 0; z < cChunkDef::Width; z++)
+		{
+			for (int x = 0; x < cChunkDef::Width; x++)
+			{
+				ComposeColumn(a_ChunkDesc, x, z, &(a_Shape[x * 256 + z * 16 * 256]));
+			}  // for x
+		}  // for z
+	}
+
+
+
+	virtual void InitializeCompoGen(cIniFile & a_IniFile) override
+	{
+		m_SeaLevel = a_IniFile.GetValueSetI("Generator", "SeaLevel", m_SeaLevel);
+	}
+	
+
+
+	/** Initializes the m_MesaPattern with a pattern based on the generator's seed. */
+	void initMesaPattern(int a_Seed)
+	{
+		// In a loop, choose whether to use one, two or three layers of stained clay, then choose a color and width for each layer
+		// Separate each group with another layer of hardened clay
+		cNoise patternNoise((unsigned)a_Seed);
+		static NIBBLETYPE allowedColors[] =
+		{
+			E_META_STAINED_CLAY_YELLOW,
+			E_META_STAINED_CLAY_YELLOW,
+			E_META_STAINED_CLAY_RED,
+			E_META_STAINED_CLAY_RED,
+			E_META_STAINED_CLAY_WHITE,
+			E_META_STAINED_CLAY_BROWN,
+			E_META_STAINED_CLAY_BROWN,
+			E_META_STAINED_CLAY_BROWN,
+			E_META_STAINED_CLAY_ORANGE,
+			E_META_STAINED_CLAY_ORANGE,
+			E_META_STAINED_CLAY_ORANGE,
+			E_META_STAINED_CLAY_ORANGE,
+			E_META_STAINED_CLAY_ORANGE,
+			E_META_STAINED_CLAY_ORANGE,
+			E_META_STAINED_CLAY_LIGHTGRAY,
+		} ;
+		static int layerSizes[] =  // Adjust the chance so that thinner layers occur more commonly
+		{
+			1, 1, 1, 1, 1, 1,
+			2, 2, 2, 2,
+			3, 3,
+		} ;
+		int idx = ARRAYCOUNT(m_MesaPattern) - 1;
+		while (idx >= 0)
+		{
+			// A layer group of 1 - 2 color stained clay:
+			int rnd = patternNoise.IntNoise1DInt(idx) / 7;
+			int numLayers = (rnd % 2) + 1;
+			rnd /= 2;
+			for (int lay = 0; lay < numLayers; lay++)
+			{
+				int numBlocks = layerSizes[(rnd % ARRAYCOUNT(layerSizes))];
+				NIBBLETYPE Color = allowedColors[(rnd / 4) % ARRAYCOUNT(allowedColors)];
+				if (
+					((numBlocks == 3) && (numLayers == 2)) ||  // In two-layer mode disallow the 3-high layers:
+					(Color == E_META_STAINED_CLAY_WHITE))      // White stained clay can ever be only 1 block high
+				{
+					numBlocks = 1;
+				}
+				numBlocks = std::min(idx + 1, numBlocks);  // Limit by idx so that we don't have to check inside the loop
+				rnd /= 32;
+				for (int block = 0; block < numBlocks; block++, idx--)
+				{
+					m_MesaPattern[idx].m_BlockMeta = Color;
+					m_MesaPattern[idx].m_BlockType = E_BLOCK_STAINED_CLAY;
+				}  // for block
+			}  // for lay
+
+			// A layer of hardened clay in between the layer group:
+			int numBlocks = (rnd % 4) + 1;  // All heights the same probability
+			if ((numLayers == 2) && (numBlocks < 4))
+			{
+				// For two layers of stained clay, add an extra block of hardened clay:
+				numBlocks++;
+			}
+			numBlocks = std::min(idx + 1, numBlocks);  // Limit by idx so that we don't have to check inside the loop
+			for (int block = 0; block < numBlocks; block++, idx--)
+			{
+				m_MesaPattern[idx].m_BlockMeta = 0;
+				m_MesaPattern[idx].m_BlockType = E_BLOCK_HARDENED_CLAY;
+			}  // for block
+		}  // while (idx >= 0)
+	}
+
+
+
+	/** Composes a single column in a_ChunkDesc. Chooses what to do based on the biome in that column. */
+	void ComposeColumn(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ, const Byte * a_ShapeColumn)
+	{
+		// Frequencies for the podzol floor selecting noise:
+		const NOISE_DATATYPE FrequencyX = 8;
+		const NOISE_DATATYPE FrequencyZ = 8;
+	
+		EMCSBiome Biome = a_ChunkDesc.GetBiome(a_RelX, a_RelZ);
+		switch (Biome)
+		{
+			case biOcean:
+			case biPlains:
+			case biForest:
+			case biTaiga:
+			case biSwampland:
+			case biRiver:
+			case biFrozenOcean:
+			case biFrozenRiver:
+			case biIcePlains:
+			case biIceMountains:
+			case biForestHills:
+			case biTaigaHills:
+			case biExtremeHillsEdge:
+			case biExtremeHillsPlus:
+			case biExtremeHills:
+			case biJungle:
+			case biJungleHills:
+			case biJungleEdge:
+			case biDeepOcean:
+			case biStoneBeach:
+			case biColdBeach:
+			case biBirchForest:
+			case biBirchForestHills:
+			case biRoofedForest:
+			case biColdTaiga:
+			case biColdTaigaHills:
+			case biSavanna:
+			case biSavannaPlateau:
+			case biSunflowerPlains:
+			case biFlowerForest:
+			case biTaigaM:
+			case biSwamplandM:
+			case biIcePlainsSpikes:
+			case biJungleM:
+			case biJungleEdgeM:
+			case biBirchForestM:
+			case biBirchForestHillsM:
+			case biRoofedForestM:
+			case biColdTaigaM:
+			case biSavannaM:
+			case biSavannaPlateauM:
+			{
+				FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, patGrass.Get(), a_ShapeColumn);
+				return;
+			}
+
+			case biMegaTaiga:
+			case biMegaTaigaHills:
+			case biMegaSpruceTaiga:
+			case biMegaSpruceTaigaHills:
+			{
+				// Select the pattern to use - podzol, grass or grassless dirt:
+				NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(a_ChunkDesc.GetChunkX() * cChunkDef::Width + a_RelX)) / FrequencyX;
+				NOISE_DATATYPE NoiseY = ((NOISE_DATATYPE)(a_ChunkDesc.GetChunkZ() * cChunkDef::Width + a_RelZ)) / FrequencyZ;
+				NOISE_DATATYPE Val = m_OceanFloorSelect.CubicNoise2D(NoiseX, NoiseY);
+				const cPattern::BlockInfo * Pattern = (Val < -0.9) ? patGrassLess.Get() : ((Val > 0) ? patPodzol.Get() : patGrass.Get());
+				FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, Pattern, a_ShapeColumn);
+				return;
+			}
+
+			case biDesertHills:
+			case biDesert:
+			case biDesertM:
+			case biBeach:
+			{
+				FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, patSand.Get(), a_ShapeColumn);
+				return;
+			}
+		
+			case biMushroomIsland:
+			case biMushroomShore:
+			{
+				FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, patMycelium.Get(), a_ShapeColumn);
+				return;
+			}
+
+			case biMesa:
+			case biMesaPlateauF:
+			case biMesaPlateau:
+			case biMesaBryce:
+			case biMesaPlateauFM:
+			case biMesaPlateauM:
+			{
+				// Mesa biomes need special handling, because they don't follow the usual "4 blocks from top pattern",
+				// instead, they provide a "from bottom" pattern with varying base height,
+				// usually 4 blocks below the ocean level
+				FillColumnMesa(a_ChunkDesc, a_RelX, a_RelZ, a_ShapeColumn);
+				return;
+			}
+
+			case biExtremeHillsPlusM:
+			case biExtremeHillsM:
+			{
+				// Select the pattern to use - gravel, stone or grass:
+				NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(a_ChunkDesc.GetChunkX() * cChunkDef::Width + a_RelX)) / FrequencyX;
+				NOISE_DATATYPE NoiseY = ((NOISE_DATATYPE)(a_ChunkDesc.GetChunkZ() * cChunkDef::Width + a_RelZ)) / FrequencyZ;
+				NOISE_DATATYPE Val = m_OceanFloorSelect.CubicNoise2D(NoiseX, NoiseY);
+				const cPattern::BlockInfo * Pattern = (Val < 0.0) ? patStone.Get() : patGrass.Get();
+				FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, Pattern, a_ShapeColumn);
+				return;
+			}
+			default:
+			{
+				ASSERT(!"Unhandled biome");
+				return;
+			}
+		}  // switch (Biome)
+	}
+	
+
+
+	/** Fills the specified column with the specified pattern; restarts the pattern when air is reached,
+	switches to ocean floor pattern if ocean is reached. Always adds bedrock at the very bottom. */
+	void FillColumnPattern(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ, const cPattern::BlockInfo * a_Pattern, const Byte * a_ShapeColumn)
+	{
+		bool HasHadWater = false;
+		int PatternIdx = 0;
+		int top = std::max(m_SeaLevel, a_ChunkDesc.GetHeight(a_RelX, a_RelZ));
+		for (int y = top; y > 0; y--)
+		{
+			if (a_ShapeColumn[y] > 0)
+			{
+				// "ground" part, use the pattern:
+				a_ChunkDesc.SetBlockTypeMeta(a_RelX, y, a_RelZ, a_Pattern[PatternIdx].m_BlockType, a_Pattern[PatternIdx].m_BlockMeta);
+				PatternIdx++;
+				continue;
+			}
+		
+			// "air" or "water" part:
+			// Reset the pattern index to zero, so that the pattern is repeated from the top again:
+			PatternIdx = 0;
+		
+			if (y >= m_SeaLevel)
+			{
+				// "air" part, do nothing
+				continue;
+			}
+		
+			a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_STATIONARY_WATER);
+			if (HasHadWater)
+			{
+				continue;
+			}
+		
+			// Select the ocean-floor pattern to use:
+			if (a_ChunkDesc.GetBiome(a_RelX, a_RelZ) == biDeepOcean)
+			{
+				a_Pattern = patGravel.Get();
+			}
+			else
+			{
+				a_Pattern = ChooseOceanFloorPattern(a_ChunkDesc.GetChunkX(), a_ChunkDesc.GetChunkZ(), a_RelX, a_RelZ);
+			}
+			HasHadWater = true;
+		}  // for y
+		a_ChunkDesc.SetBlockType(a_RelX, 0, a_RelZ, E_BLOCK_BEDROCK);
+	}
+
+
+
+	/** Fills the specified column with mesa pattern, based on the column height */
+	void FillColumnMesa(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ, const Byte * a_ShapeColumn)
+	{
+		// Frequencies for the clay floor noise:
+		const NOISE_DATATYPE FrequencyX = 50;
+		const NOISE_DATATYPE FrequencyZ = 50;
+
+		int Top = a_ChunkDesc.GetHeight(a_RelX, a_RelZ);
+		if (Top < m_SeaLevel)
+		{
+			// The terrain is below sealevel, handle as regular ocean with red sand floor:
+			FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, patOFOrangeClay.Get(), a_ShapeColumn);
+			return;
+		}
+
+		NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(a_ChunkDesc.GetChunkX() * cChunkDef::Width + a_RelX)) / FrequencyX;
+		NOISE_DATATYPE NoiseY = ((NOISE_DATATYPE)(a_ChunkDesc.GetChunkZ() * cChunkDef::Width + a_RelZ)) / FrequencyZ;
+		int ClayFloor = m_SeaLevel - 6 + (int)(4.f * m_MesaFloor.CubicNoise2D(NoiseX, NoiseY));
+		if (ClayFloor >= Top)
+		{
+			ClayFloor = Top - 1;
+		}
+	
+		if (Top - m_SeaLevel < 5)
+		{
+			// Simple case: top is red sand, then hardened clay down to ClayFloor, then stone:
+			a_ChunkDesc.SetBlockTypeMeta(a_RelX, Top, a_RelZ, E_BLOCK_SAND, E_META_SAND_RED);
+			for (int y = Top - 1; y >= ClayFloor; y--)
+			{
+				a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_HARDENED_CLAY);
+			}
+			for (int y = ClayFloor - 1; y > 0; y--)
+			{
+				a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_STONE);
+			}
+			a_ChunkDesc.SetBlockType(a_RelX, 0, a_RelZ, E_BLOCK_BEDROCK);
+			return;
+		}
+	
+		// Difficult case: use the mesa pattern and watch for overhangs:
+		int PatternIdx = cChunkDef::Height - (Top - ClayFloor);  // We want the block at index ClayFloor to be pattern's 256th block (first stone)
+		const cPattern::BlockInfo * Pattern = m_MesaPattern;
+		bool HasHadWater = false;
+		for (int y = Top; y > 0; y--)
+		{
+			if (a_ShapeColumn[y] > 0)
+			{
+				// "ground" part, use the pattern:
+				a_ChunkDesc.SetBlockTypeMeta(a_RelX, y, a_RelZ, Pattern[PatternIdx].m_BlockType, Pattern[PatternIdx].m_BlockMeta);
+				PatternIdx++;
+				continue;
+			}
+
+			if (y >= m_SeaLevel)
+			{
+				// "air" part, do nothing
+				continue;
+			}
+		
+			// "water" part, fill with water and choose new pattern for ocean floor, if not chosen already:
+			PatternIdx = 0;
+			a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_STATIONARY_WATER);
+			if (HasHadWater)
+			{
+				continue;
+			}
+		
+			// Select the ocean-floor pattern to use:
+			Pattern = ChooseOceanFloorPattern(a_ChunkDesc.GetChunkX(), a_ChunkDesc.GetChunkZ(), a_RelX, a_RelZ);
+			HasHadWater = true;
+		}  // for y
+		a_ChunkDesc.SetBlockType(a_RelX, 0, a_RelZ, E_BLOCK_BEDROCK);
+	}
+
+
+	
+	/** Returns the pattern to use for an ocean floor in the specified column.
+	The returned pattern is guaranteed to be 256 blocks long. */
+	const cPattern::BlockInfo * ChooseOceanFloorPattern(int a_ChunkX, int a_ChunkZ, int a_RelX, int a_RelZ)
+	{
+		// Frequencies for the ocean floor selecting noise:
+		const NOISE_DATATYPE FrequencyX = 3;
+		const NOISE_DATATYPE FrequencyZ = 3;
+
+		// Select the ocean-floor pattern to use:
+		NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(a_ChunkX * cChunkDef::Width + a_RelX)) / FrequencyX;
+		NOISE_DATATYPE NoiseY = ((NOISE_DATATYPE)(a_ChunkZ * cChunkDef::Width + a_RelZ)) / FrequencyZ;
+		NOISE_DATATYPE Val = m_OceanFloorSelect.CubicNoise2D(NoiseX, NoiseY);
+		if (Val < -0.95)
+		{
+			return patOFClay.Get();
+		}
+		else if (Val < 0)
+		{
+			return patOFSand.Get();
+		}
+		else
+		{
+			return patDirt.Get();
+		}
+	}
+} ;
+
+
+
+
+
+cTerrainCompositionGenPtr CreateCompoGenBiomal(int a_Seed)
+{
+	return std::make_shared<cCompoGenBiomal>(a_Seed);
+}
+
+
+
diff --git a/src/Generating/CompoGenBiomal.h b/src/Generating/CompoGenBiomal.h
new file mode 100644
index 000000000..a3a65d3dc
--- /dev/null
+++ b/src/Generating/CompoGenBiomal.h
@@ -0,0 +1,21 @@
+
+// CompoGenBiomal.h
+
+
+
+
+
+#pragma once
+
+#include "ComposableGenerator.h"
+
+
+
+
+
+/** Returns a new instance of the Biomal composition generator. */
+cTerrainCompositionGenPtr CreateCompoGenBiomal(int a_Seed);
+
+
+
+
diff --git a/src/Generating/ComposableGenerator.cpp b/src/Generating/ComposableGenerator.cpp
index 5f46574c7..4192dfa72 100644
--- a/src/Generating/ComposableGenerator.cpp
+++ b/src/Generating/ComposableGenerator.cpp
@@ -17,6 +17,10 @@
 #include "StructGen.h"
 #include "FinishGen.h"
 
+#include "CompoGenBiomal.h"
+
+#include "CompositedHeiGen.h"
+
 #include "Caves.h"
 #include "DistortedHeightmap.h"
 #include "DungeonRoomsFinisher.h"
@@ -39,7 +43,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 // cTerrainCompositionGen:
 
-cTerrainCompositionGenPtr cTerrainCompositionGen::CreateCompositionGen(cIniFile & a_IniFile, cBiomeGenPtr a_BiomeGen, cTerrainHeightGen & a_HeightGen, int a_Seed)
+cTerrainCompositionGenPtr cTerrainCompositionGen::CreateCompositionGen(cIniFile & a_IniFile, cBiomeGenPtr a_BiomeGen, cTerrainShapeGenPtr a_ShapeGen, int a_Seed)
 {
 	AString CompoGenName = a_IniFile.GetValueSet("Generator", "CompositionGen", "");
 	if (CompoGenName.empty())
@@ -48,63 +52,52 @@ cTerrainCompositionGenPtr cTerrainCompositionGen::CreateCompositionGen(cIniFile
 		CompoGenName = "Biomal";
 	}
 	
-	cTerrainCompositionGen * res = nullptr;
-	if (NoCaseCompare(CompoGenName, "sameblock") == 0)
+	// Compositor list is alpha-sorted
+	cTerrainCompositionGenPtr res;
+	if (NoCaseCompare(CompoGenName, "Biomal") == 0)
 	{
-		res = new cCompoGenSameBlock;
+		res = CreateCompoGenBiomal(a_Seed);
 	}
-	else if (NoCaseCompare(CompoGenName, "debugbiomes") == 0)
+	else if (NoCaseCompare(CompoGenName, "BiomalNoise3D") == 0)
 	{
-		res = new cCompoGenDebugBiomes;
+		// The composition that used to be provided with BiomalNoise3D is now provided by the Biomal compositor:
+		res = CreateCompoGenBiomal(a_Seed);
 	}
-	else if (NoCaseCompare(CompoGenName, "classic") == 0)
+	else if (NoCaseCompare(CompoGenName, "Classic") == 0)
 	{
-		res = new cCompoGenClassic;
+		res = std::make_shared<cCompoGenClassic>();
 	}
-	else if (NoCaseCompare(CompoGenName, "DistortedHeightmap") == 0)
+	else if (NoCaseCompare(CompoGenName, "DebugBiomes") == 0)
 	{
-		res = new cDistortedHeightmap(a_Seed, a_BiomeGen);
+		res = std::make_shared<cCompoGenDebugBiomes>();
 	}
-	else if (NoCaseCompare(CompoGenName, "end") == 0)
+	else if (NoCaseCompare(CompoGenName, "DistortedHeightmap") == 0)
 	{
-		res = new cEndGen(a_Seed);
+		// The composition that used to be provided with DistortedHeightmap is now provided by the Biomal compositor:
+		res = CreateCompoGenBiomal(a_Seed);
 	}
-	else if (NoCaseCompare(CompoGenName, "nether") == 0)
+	else if (NoCaseCompare(CompoGenName, "End") == 0)
 	{
-		res = new cCompoGenNether(a_Seed);
+		res = std::make_shared<cEndGen>(a_Seed);
 	}
-	else if (NoCaseCompare(CompoGenName, "BiomalNoise3D") == 0)
+	else if (NoCaseCompare(CompoGenName, "Nether") == 0)
 	{
-		res = new cBiomalNoise3DComposable(a_Seed, a_BiomeGen);
+		res = std::make_shared<cCompoGenNether>(a_Seed);
 	}
 	else if (NoCaseCompare(CompoGenName, "Noise3D") == 0)
 	{
-		res = new cNoise3DComposable(a_Seed);
+		// The composition that used to be provided with Noise3D is now provided by the Biomal compositor:
+		res = CreateCompoGenBiomal(a_Seed);
 	}
-	else if (NoCaseCompare(CompoGenName, "biomal") == 0)
+	else if (NoCaseCompare(CompoGenName, "SameBlock") == 0)
 	{
-		res = new cCompoGenBiomal(a_Seed);
-
-		/*
-		// Performance-testing:
-		LOGINFO("Measuring performance of cCompoGenBiomal...");
-		clock_t BeginTick = clock();
-		for (int x = 0; x < 500; x++)
-		{
-			cChunkDesc Desc(200 + x * 8, 200 + x * 8);
-			a_BiomeGen->GenBiomes(Desc.GetChunkX(), Desc.GetChunkZ(), Desc.GetBiomeMap());
-			a_HeightGen->GenHeightMap(Desc.GetChunkX(), Desc.GetChunkZ(), Desc.GetHeightMap());
-			res->ComposeTerrain(Desc);
-		}
-		clock_t Duration = clock() - BeginTick;
-		LOGINFO("CompositionGen for 500 chunks took %d ticks (%.02f sec)", Duration, (double)Duration / CLOCKS_PER_SEC);
-		//*/
+		res = std::make_shared<cCompoGenSameBlock>();
 	}
 	else
 	{
 		LOGWARN("Unknown CompositionGen \"%s\", using \"Biomal\" instead.", CompoGenName.c_str());
 		a_IniFile.SetValue("Generator", "CompositionGen", "Biomal");
-		return CreateCompositionGen(a_IniFile, a_BiomeGen, a_HeightGen, a_Seed);
+		return CreateCompositionGen(a_IniFile, a_BiomeGen, a_ShapeGen, a_Seed);
 	}
 	ASSERT(res != nullptr);
 	
@@ -124,7 +117,7 @@ cTerrainCompositionGenPtr cTerrainCompositionGen::CreateCompositionGen(cIniFile
 cComposableGenerator::cComposableGenerator(cChunkGenerator & a_ChunkGenerator) :
 	super(a_ChunkGenerator),
 	m_BiomeGen(),
-	m_HeightGen(),
+	m_ShapeGen(),
 	m_CompositionGen()
 {
 }
@@ -138,7 +131,7 @@ void cComposableGenerator::Initialize(cIniFile & a_IniFile)
 	super::Initialize(a_IniFile);
 	
 	InitBiomeGen(a_IniFile);
-	InitHeightGen(a_IniFile);
+	InitShapeGen(a_IniFile);
 	InitCompositionGen(a_IniFile);
 	InitFinishGens(a_IniFile);
 }
@@ -166,16 +159,22 @@ void cComposableGenerator::DoGenerate(int a_ChunkX, int a_ChunkZ, cChunkDesc & a
 		m_BiomeGen->GenBiomes(a_ChunkX, a_ChunkZ, a_ChunkDesc.GetBiomeMap());
 	}
 	
+	cChunkDesc::Shape shape;
 	if (a_ChunkDesc.IsUsingDefaultHeight())
 	{
-		m_HeightGen->GenHeightMap(a_ChunkX, a_ChunkZ, a_ChunkDesc.GetHeightMap());
+		m_ShapeGen->GenShape(a_ChunkX, a_ChunkZ, shape);
+		a_ChunkDesc.SetHeightFromShape(shape);
+	}
+	else
+	{
+		// Convert the heightmap in a_ChunkDesc into shape:
+		a_ChunkDesc.GetShapeFromHeight(shape);
 	}
 	
 	bool ShouldUpdateHeightmap = false;
 	if (a_ChunkDesc.IsUsingDefaultComposition())
 	{
-		m_CompositionGen->ComposeTerrain(a_ChunkDesc);
-		ShouldUpdateHeightmap = true;
+		m_CompositionGen->ComposeTerrain(a_ChunkDesc, shape);
 	}
 
 	if (a_ChunkDesc.IsUsingDefaultFinish())
@@ -234,13 +233,15 @@ void cComposableGenerator::InitBiomeGen(cIniFile & a_IniFile)
 
 
 
-void cComposableGenerator::InitHeightGen(cIniFile & a_IniFile)
+void cComposableGenerator::InitShapeGen(cIniFile & a_IniFile)
 {
 	bool CacheOffByDefault = false;
-	m_HeightGen = cTerrainHeightGen::CreateHeightGen(a_IniFile, m_BiomeGen, m_ChunkGenerator.GetSeed(), CacheOffByDefault);
+	m_ShapeGen = cTerrainShapeGen::CreateShapeGen(a_IniFile, m_BiomeGen, m_ChunkGenerator.GetSeed(), CacheOffByDefault);
 	
+	/*
+	// TODO
 	// Add a cache, if requested:
-	int CacheSize = a_IniFile.GetValueSetI("Generator", "HeightGenCacheSize", CacheOffByDefault ? 0 : 64);
+	int CacheSize = a_IniFile.GetValueSetI("Generator", "ShapeGenCacheSize", CacheOffByDefault ? 0 : 64);
 	if (CacheSize > 0)
 	{
 		if (CacheSize < 4)
@@ -253,6 +254,7 @@ void cComposableGenerator::InitHeightGen(cIniFile & a_IniFile)
 		LOGD("Using a cache for Heightgen of size %d.", CacheSize);
 		m_HeightGen = cTerrainHeightGenPtr(new cHeiGenCache(m_HeightGen, CacheSize));
 	}
+	*/
 }
 
 
@@ -261,13 +263,19 @@ void cComposableGenerator::InitHeightGen(cIniFile & a_IniFile)
 
 void cComposableGenerator::InitCompositionGen(cIniFile & a_IniFile)
 {
-	m_CompositionGen = cTerrainCompositionGen::CreateCompositionGen(a_IniFile, m_BiomeGen, *m_HeightGen, m_ChunkGenerator.GetSeed());
+	m_CompositionGen = cTerrainCompositionGen::CreateCompositionGen(a_IniFile, m_BiomeGen, m_ShapeGen, m_ChunkGenerator.GetSeed());
 	
+	// Add a cache over the composition generator:
+	// Even a cache of size 1 is useful due to the CompositedHeiGen cache after us doing re-composition on its misses
 	int CompoGenCacheSize = a_IniFile.GetValueSetI("Generator", "CompositionGenCacheSize", 64);
-	if (CompoGenCacheSize > 1)
+	if (CompoGenCacheSize > 0)
 	{
-		m_CompositionGen = cTerrainCompositionGenPtr(new cCompoGenCache(m_CompositionGen, 32));
+		m_CompositionGen = std::make_shared<cCompoGenCache>(m_CompositionGen, CompoGenCacheSize);
 	}
+
+	// Create a cache of the composited heightmaps, so that finishers may use it:
+	m_CompositedHeightCache = std::make_shared<cHeiGenMultiCache>(std::make_shared<cCompositedHeiGen>(m_ShapeGen, m_CompositionGen), 16, 24);
+	// 24 subcaches of depth 16 each = 96 KiB of RAM. Acceptable, for the amount of work this saves.
 }
 
 
@@ -333,7 +341,7 @@ void cComposableGenerator::InitFinishGens(cIniFile & a_IniFile)
 			int     MaxSize       = a_IniFile.GetValueSetI("Generator", "DungeonRoomsMaxSize", 7);
 			int     MinSize       = a_IniFile.GetValueSetI("Generator", "DungeonRoomsMinSize", 5);
 			AString HeightDistrib = a_IniFile.GetValueSet ("Generator", "DungeonRoomsHeightDistrib", "0, 0; 10, 10; 11, 500; 40, 500; 60, 40; 90, 1");
-			m_FinishGens.push_back(cFinishGenPtr(new cDungeonRoomsFinisher(m_HeightGen, Seed, GridSize, MaxSize, MinSize, HeightDistrib)));
+			m_FinishGens.push_back(cFinishGenPtr(new cDungeonRoomsFinisher(m_ShapeGen, Seed, GridSize, MaxSize, MinSize, HeightDistrib)));
 		}
 		else if (NoCaseCompare(*itr, "Ice") == 0)
 		{
@@ -342,7 +350,7 @@ void cComposableGenerator::InitFinishGens(cIniFile & a_IniFile)
 		else if (NoCaseCompare(*itr, "LavaLakes") == 0)
 		{
 			int Probability = a_IniFile.GetValueSetI("Generator", "LavaLakesProbability", 10);
-			m_FinishGens.push_back(cFinishGenPtr(new cStructGenLakes(Seed * 5 + 16873, E_BLOCK_STATIONARY_LAVA, m_HeightGen, Probability)));
+			m_FinishGens.push_back(cFinishGenPtr(new cStructGenLakes(Seed * 5 + 16873, E_BLOCK_STATIONARY_LAVA, m_ShapeGen, Probability)));
 		}
 		else if (NoCaseCompare(*itr, "LavaSprings") == 0)
 		{
@@ -580,7 +588,7 @@ void cComposableGenerator::InitFinishGens(cIniFile & a_IniFile)
 		}
 		else if (NoCaseCompare(*itr, "Trees") == 0)
 		{
-			m_FinishGens.push_back(cFinishGenPtr(new cStructGenTrees(Seed, m_BiomeGen, m_HeightGen, m_CompositionGen)));
+			m_FinishGens.push_back(cFinishGenPtr(new cStructGenTrees(Seed, m_BiomeGen, m_ShapeGen, m_CompositionGen)));
 		}
 		else if (NoCaseCompare(*itr, "UnderwaterBases") == 0)
 		{
@@ -588,7 +596,7 @@ void cComposableGenerator::InitFinishGens(cIniFile & a_IniFile)
 			int MaxOffset = a_IniFile.GetValueSetI("Generator", "UnderwaterBaseMaxOffset", 128);
 			int MaxDepth  = a_IniFile.GetValueSetI("Generator", "UnderwaterBaseMaxDepth",    7);
 			int MaxSize   = a_IniFile.GetValueSetI("Generator", "UnderwaterBaseMaxSize",   128);
-			m_FinishGens.push_back(cFinishGenPtr(new cUnderwaterBaseGen(Seed, GridSize, MaxOffset, MaxDepth, MaxSize, m_BiomeGen)));
+			m_FinishGens.push_back(std::make_shared<cUnderwaterBaseGen>(Seed, GridSize, MaxOffset, MaxDepth, MaxSize, m_BiomeGen));
 		}
 		else if (NoCaseCompare(*itr, "Villages") == 0)
 		{
@@ -598,12 +606,12 @@ void cComposableGenerator::InitFinishGens(cIniFile & a_IniFile)
 			int MaxSize    = a_IniFile.GetValueSetI("Generator", "VillageMaxSize",   128);
 			int MinDensity = a_IniFile.GetValueSetI("Generator", "VillageMinDensity", 50);
 			int MaxDensity = a_IniFile.GetValueSetI("Generator", "VillageMaxDensity", 80);
-			m_FinishGens.push_back(cFinishGenPtr(new cVillageGen(Seed, GridSize, MaxOffset, MaxDepth, MaxSize, MinDensity, MaxDensity, m_BiomeGen, m_HeightGen)));
+			m_FinishGens.push_back(std::make_shared<cVillageGen>(Seed, GridSize, MaxOffset, MaxDepth, MaxSize, MinDensity, MaxDensity, m_BiomeGen, m_CompositedHeightCache));
 		}
 		else if (NoCaseCompare(*itr, "WaterLakes") == 0)
 		{
 			int Probability = a_IniFile.GetValueSetI("Generator", "WaterLakesProbability", 25);
-			m_FinishGens.push_back(cFinishGenPtr(new cStructGenLakes(Seed * 3 + 652, E_BLOCK_STATIONARY_WATER, m_HeightGen, Probability)));
+			m_FinishGens.push_back(cFinishGenPtr(new cStructGenLakes(Seed * 3 + 652, E_BLOCK_STATIONARY_WATER, m_ShapeGen, Probability)));
 		}
 		else if (NoCaseCompare(*itr, "WaterSprings") == 0)
 		{
diff --git a/src/Generating/ComposableGenerator.h b/src/Generating/ComposableGenerator.h
index a091f8d53..86c30e090 100644
--- a/src/Generating/ComposableGenerator.h
+++ b/src/Generating/ComposableGenerator.h
@@ -26,20 +26,16 @@ See http://forum.mc-server.org/showthread.php?tid=409 for details.
 
 // Forward-declare the shared pointers to subgenerator classes:
 class cBiomeGen;
+class cTerrainShapeGen;
 class cTerrainHeightGen;
 class cTerrainCompositionGen;
 class cFinishGen;
 typedef SharedPtr<cBiomeGen>              cBiomeGenPtr;
+typedef SharedPtr<cTerrainShapeGen>       cTerrainShapeGenPtr;
 typedef SharedPtr<cTerrainHeightGen>      cTerrainHeightGenPtr;
 typedef SharedPtr<cTerrainCompositionGen> cTerrainCompositionGenPtr;
 typedef SharedPtr<cFinishGen>             cFinishGenPtr;
 
-// fwd: Noise3DGenerator.h
-class cNoise3DComposable;
-
-// fwd: DistortedHeightmap.h
-class cDistortedHeightmap;
-
 
 
 
@@ -70,28 +66,54 @@ public:
 
 
 
-/** The interface that a terrain height generator must implement
-A terrain height generator takes chunk coords on input and outputs an array of terrain heights for that chunk.
-The output array is sequenced in the same way as the BiomeGen's biome data.
+/** The interface that a terrain shape generator must implement
+A terrain shape generator takes chunk coords on input and outputs a 3D array of "shape" for that chunk. The shape here
+represents the distinction between air and solid; there's no representation of Water since that is added by the
+composition geenrator.
+The output array is indexed [y + 256 * z + 16 * 256 * x], so that it's fast to later compose a single column of the terrain,
+which is the dominant operation following the shape generation.
 The generator may request biome information from the underlying BiomeGen, it may even request information for
-other chunks than the one it's currently generating (possibly neighbors - for averaging)
+other chunks than the one it's currently generating (neighbors - for averaging)
 */
-class cTerrainHeightGen
+class cTerrainShapeGen
 {
 public:
-	virtual ~cTerrainHeightGen() {}  // Force a virtual destructor in descendants
+	virtual ~cTerrainShapeGen() {}  // Force a virtual destructor in descendants
 	
-	/** Generates heightmap for the given chunk */
-	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) = 0;
+	/** Generates the shape for the given chunk */
+	virtual void GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape) = 0;
 	
 	/** Reads parameters from the ini file, prepares generator for use. */
-	virtual void InitializeHeightGen(cIniFile & a_IniFile) {}
+	virtual void InitializeShapeGen(cIniFile & a_IniFile) {}
 	
-	/** Creates the correct TerrainHeightGen descendant based on the ini file settings and the seed provided.
-	a_BiomeGen is the underlying biome generator, some height generators may depend on it to generate more biomes
+	/** Creates the correct TerrainShapeGen descendant based on the ini file settings and the seed provided.
+	a_BiomeGen is the underlying biome generator, some shape generators may depend on it providing additional biomes data around the chunk
 	a_CacheOffByDefault gets set to whether the cache should be disabled by default
-	Implemented in HeiGen.cpp!
+	Implemented in ShapeGen.cpp!
 	*/
+	static cTerrainShapeGenPtr CreateShapeGen(cIniFile & a_IniFile, cBiomeGenPtr a_BiomeGen, int a_Seed, bool & a_CacheOffByDefault);
+} ;
+
+
+
+
+
+/** The interface that is used to query terrain height from the shape generator.
+Usually the structure generators require only the final heightmap, and generating the whole shape only to
+consume the heightmap is wasteful, so this interface is used instead; it has a cache implemented over it so
+that data is retained. */
+class cTerrainHeightGen
+{
+public:
+	virtual ~cTerrainHeightGen() {}  // Force a virtual destructor in descendants
+
+	/** Retrieves the heightmap for the specified chunk. */
+	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) = 0;
+
+	/** Initializes the generator, reading its parameters from the INI file. */
+	virtual void InitializeHeightGen(cIniFile & a_IniFile) {}
+
+	/** Creates a cTerrainHeightGen descendant based on the INI file settings. */
 	static cTerrainHeightGenPtr CreateHeightGen(cIniFile & a_IniFile, cBiomeGenPtr a_BiomeGen, int a_Seed, bool & a_CacheOffByDefault);
 } ;
 
@@ -109,16 +131,18 @@ class cTerrainCompositionGen
 public:
 	virtual ~cTerrainCompositionGen() {}  // Force a virtual destructor in descendants
 	
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) = 0;
+	/** Generates the chunk's composition into a_ChunkDesc, using the terrain shape provided in a_Shape.
+	Is expected to fill a_ChunkDesc's heightmap with the data from a_Shape. */
+	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape) = 0;
 	
 	/** Reads parameters from the ini file, prepares generator for use. */
 	virtual void InitializeCompoGen(cIniFile & a_IniFile) {}
 	
 	/** Creates the correct TerrainCompositionGen descendant based on the ini file settings and the seed provided.
-	a_BiomeGen is the underlying biome generator, some composition generators may depend on it to generate more biomes
-	a_HeightGen is the underlying height generator, some composition generators may depend on it providing additional values
+	a_BiomeGen is the underlying biome generator, some composition generators may depend on it providing additional biomes around the chunk
+	a_ShapeGen is the underlying shape generator, some composition generators may depend on it providing additional shape around the chunk
 	*/
-	static cTerrainCompositionGenPtr CreateCompositionGen(cIniFile & a_IniFile, cBiomeGenPtr a_BiomeGen, cTerrainHeightGen & a_HeightGen, int a_Seed);
+	static cTerrainCompositionGenPtr CreateCompositionGen(cIniFile & a_IniFile, cBiomeGenPtr a_BiomeGen, cTerrainShapeGenPtr a_ShapeGen, int a_Seed);
 } ;
 
 
@@ -128,7 +152,7 @@ public:
 /** The interface that a finisher must implement
 Finisher implements changes to the chunk after the rough terrain has been generated.
 Examples of finishers are trees, snow, ore, lilypads and others.
-Note that a worldgenerator may contain multiple finishers.
+Note that a worldgenerator may contain multiple finishers, chained one after another.
 Also note that previously we used to distinguish between a structuregen and a finisher; this distinction is
 no longer relevant, all structure generators are considered finishers now (#398)
 */
@@ -154,23 +178,34 @@ class cComposableGenerator :
 public:
 	cComposableGenerator(cChunkGenerator & a_ChunkGenerator);
 	
+	// cChunkGenerator::cGenerator overrides:
 	virtual void Initialize(cIniFile & a_IniFile) override;
 	virtual void GenerateBiomes(int a_ChunkX, int a_ChunkZ, cChunkDef::BiomeMap & a_BiomeMap) override;
 	virtual void DoGenerate(int a_ChunkX, int a_ChunkZ, cChunkDesc & a_ChunkDesc) override;
 
 protected:
-	// The generation composition:
-	cBiomeGenPtr              m_BiomeGen;
-	cTerrainHeightGenPtr      m_HeightGen;
+	// The generator's composition:
+	/** The biome generator. */
+	cBiomeGenPtr m_BiomeGen;
+
+	/** The terrain shape generator. */
+	cTerrainShapeGenPtr m_ShapeGen;
+
+	/** The terrain composition generator. */
 	cTerrainCompositionGenPtr m_CompositionGen;
-	cFinishGenList            m_FinishGens;
+
+	/** The cache for the heights of the composited terrain. */
+	cTerrainHeightGenPtr m_CompositedHeightCache;
+
+	/** The finisher generators, in the order in which they are applied. */
+	cFinishGenList m_FinishGens;
 	
 	
-	/** Reads the biome gen settings from the ini and initializes m_BiomeGen accordingly */
+	/** Reads the BiomeGen settings from the ini and initializes m_BiomeGen accordingly */
 	void InitBiomeGen(cIniFile & a_IniFile);
 	
-	/** Reads the HeightGen settings from the ini and initializes m_HeightGen accordingly */
-	void InitHeightGen(cIniFile & a_IniFile);
+	/** Reads the ShapeGen settings from the ini and initializes m_ShapeGen accordingly */
+	void InitShapeGen(cIniFile & a_IniFile);
 	
 	/** Reads the CompositionGen settings from the ini and initializes m_CompositionGen accordingly */
 	void InitCompositionGen(cIniFile & a_IniFile);
diff --git a/src/Generating/CompositedHeiGen.h b/src/Generating/CompositedHeiGen.h
new file mode 100644
index 000000000..fa33a7861
--- /dev/null
+++ b/src/Generating/CompositedHeiGen.h
@@ -0,0 +1,49 @@
+
+// CompositedHeiGen.h
+
+// Declares the cCompositedHeiGen class representing a cTerrainHeightGen descendant that calculates heightmap of the composited terrain
+// This is used to further cache heightmaps for chunks already generated for finishers that require only heightmap information
+
+
+
+
+
+#pragma once
+
+#include "ComposableGenerator.h"
+
+
+
+
+
+class cCompositedHeiGen:
+	public cTerrainHeightGen
+{
+public:
+	cCompositedHeiGen(cTerrainShapeGenPtr a_ShapeGen, cTerrainCompositionGenPtr a_CompositionGen):
+		m_ShapeGen(a_ShapeGen),
+		m_CompositionGen(a_CompositionGen)
+	{
+	}
+
+
+
+	// cTerrainheightGen overrides:
+	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override
+	{
+		cChunkDesc::Shape shape;
+		m_ShapeGen->GenShape(a_ChunkX, a_ChunkZ, shape);
+		cChunkDesc desc(a_ChunkX, a_ChunkZ);
+		desc.SetHeightFromShape(shape);
+		m_CompositionGen->ComposeTerrain(desc, shape);
+		memcpy(a_HeightMap, desc.GetHeightMap(), sizeof(a_HeightMap));
+	}
+
+protected:
+	cTerrainShapeGenPtr m_ShapeGen;
+	cTerrainCompositionGenPtr m_CompositionGen;
+};
+
+
+
+
diff --git a/src/Generating/DistortedHeightmap.cpp b/src/Generating/DistortedHeightmap.cpp
index d5bc6ab55..e1ed9b450 100644
--- a/src/Generating/DistortedHeightmap.cpp
+++ b/src/Generating/DistortedHeightmap.cpp
@@ -15,163 +15,6 @@
 
 
 ////////////////////////////////////////////////////////////////////////////////
-// cPattern:
-
-/// This class is used to store a column pattern initialized at runtime,
-/// so that the program doesn't need to explicitly set 256 values for each pattern
-/// Each pattern has 256 blocks so that there's no need to check pattern bounds when assigning the
-/// pattern - there will always be enough pattern left, even for the whole chunk height
-class cPattern
-{
-public:
-	cPattern(cDistortedHeightmap::sBlockInfo * a_TopBlocks, size_t a_Count)
-	{
-		// Copy the pattern into the top:
-		for (size_t i = 0; i < a_Count; i++)
-		{
-			m_Pattern[i] = a_TopBlocks[i];
-		}
-		
-		// Fill the rest with stone:
-		static cDistortedHeightmap::sBlockInfo Stone = {E_BLOCK_STONE, 0};
-		for (size_t i = a_Count; i < cChunkDef::Height; i++)
-		{
-			m_Pattern[i] = Stone;
-		}
-	}
-	
-	const cDistortedHeightmap::sBlockInfo * Get(void) const { return m_Pattern; }
-	
-protected:
-	cDistortedHeightmap::sBlockInfo m_Pattern[cChunkDef::Height];
-} ;
-
-
-
-
-
-////////////////////////////////////////////////////////////////////////////////
-// The arrays to use for the top block pattern definitions:
-
-static cDistortedHeightmap::sBlockInfo tbGrass[] =
-{
-	{E_BLOCK_GRASS, 0},
-	{E_BLOCK_DIRT,  E_META_DIRT_NORMAL},
-	{E_BLOCK_DIRT,  E_META_DIRT_NORMAL},
-	{E_BLOCK_DIRT,  E_META_DIRT_NORMAL},
-} ;
-
-static cDistortedHeightmap::sBlockInfo tbSand[] =
-{
-	{ E_BLOCK_SAND, 0},
-	{ E_BLOCK_SAND, 0},
-	{ E_BLOCK_SAND, 0},
-	{ E_BLOCK_SANDSTONE, 0},
-} ;
-
-static cDistortedHeightmap::sBlockInfo tbDirt[] =
-{
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-} ;
-
-static cDistortedHeightmap::sBlockInfo tbPodzol[] =
-{
-	{E_BLOCK_DIRT, E_META_DIRT_PODZOL},
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-} ;
-
-static cDistortedHeightmap::sBlockInfo tbGrassLess[] =
-{
-	{E_BLOCK_DIRT, E_META_DIRT_GRASSLESS},
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-	{E_BLOCK_DIRT, E_META_DIRT_NORMAL},
-} ;
-
-static cDistortedHeightmap::sBlockInfo tbMycelium[] =
-{
-	{E_BLOCK_MYCELIUM, 0},
-	{E_BLOCK_DIRT,     0},
-	{E_BLOCK_DIRT,     0},
-	{E_BLOCK_DIRT,     0},
-} ;
-
-static cDistortedHeightmap::sBlockInfo tbGravel[] =
-{
-	{E_BLOCK_GRAVEL, 0},
-	{E_BLOCK_GRAVEL, 0},
-	{E_BLOCK_GRAVEL, 0},
-	{E_BLOCK_STONE,  0},
-} ;
-
-static cDistortedHeightmap::sBlockInfo tbStone[] =
-{
-	{E_BLOCK_STONE,   0},
-	{E_BLOCK_STONE,   0},
-	{E_BLOCK_STONE,   0},
-	{E_BLOCK_STONE,   0},
-} ;
-
-
-
-////////////////////////////////////////////////////////////////////////////////
-// Ocean floor pattern top-block definitions:
-
-static cDistortedHeightmap::sBlockInfo tbOFSand[] =
-{
-	{E_BLOCK_SAND, 0},
-	{E_BLOCK_SAND, 0},
-	{E_BLOCK_SAND, 0},
-	{E_BLOCK_SANDSTONE, 0}
-} ;
-
-static cDistortedHeightmap::sBlockInfo tbOFClay[] =
-{
-	{ E_BLOCK_CLAY, 0},
-	{ E_BLOCK_CLAY, 0},
-	{ E_BLOCK_SAND, 0},
-	{ E_BLOCK_SAND, 0},
-} ;
-
-static cDistortedHeightmap::sBlockInfo tbOFRedSand[] =
-{
-	{ E_BLOCK_SAND,      E_META_SAND_RED},
-	{ E_BLOCK_SAND,      E_META_SAND_RED},
-	{ E_BLOCK_SAND,      E_META_SAND_RED},
-	{ E_BLOCK_SANDSTONE, 0},
-} ;
-
-
-
-
-
-
-////////////////////////////////////////////////////////////////////////////////
-// Individual patterns to use:
-
-static cPattern patGrass    (tbGrass,     ARRAYCOUNT(tbGrass));
-static cPattern patSand     (tbSand,      ARRAYCOUNT(tbSand));
-static cPattern patDirt     (tbDirt,      ARRAYCOUNT(tbDirt));
-static cPattern patPodzol   (tbPodzol,    ARRAYCOUNT(tbPodzol));
-static cPattern patGrassLess(tbGrassLess, ARRAYCOUNT(tbGrassLess));
-static cPattern patMycelium (tbMycelium,  ARRAYCOUNT(tbMycelium));
-static cPattern patGravel   (tbGravel,    ARRAYCOUNT(tbGravel));
-static cPattern patStone    (tbStone,     ARRAYCOUNT(tbStone));
-
-static cPattern patOFSand   (tbOFSand,    ARRAYCOUNT(tbOFSand));
-static cPattern patOFClay   (tbOFClay,    ARRAYCOUNT(tbOFClay));
-static cPattern patOFRedSand(tbOFRedSand, ARRAYCOUNT(tbOFRedSand));
-
-
-
-
-
-////////////////////////////////////////////////////////////////////////////////
 // cDistortedHeightmap:
 
 /** This table assigns a relative maximum overhang size in each direction to biomes.
@@ -237,7 +80,7 @@ const cDistortedHeightmap::sGenParam cDistortedHeightmap::m_GenParam[256] =
 	{0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f},  // 110 .. 119
 	{0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f}, {0.0f, 0.0f},                // 120 .. 128
 	
-	// Release 1.7 /* biome variants:
+	// Release 1.7 biome variants:
 	/* biSunflowerPlains      */ { 1.0f,  1.0f},  // 129
 	/* biDesertM              */ { 1.0f,  1.0f},  // 130
 	/* biExtremeHillsM        */ {16.0f, 16.0f},  // 131
@@ -279,8 +122,6 @@ const cDistortedHeightmap::sGenParam cDistortedHeightmap::m_GenParam[256] =
 cDistortedHeightmap::cDistortedHeightmap(int a_Seed, cBiomeGenPtr a_BiomeGen) :
 	m_NoiseDistortX(a_Seed + 1000),
 	m_NoiseDistortZ(a_Seed + 2000),
-	m_OceanFloorSelect(a_Seed + 3000),
-	m_MesaFloor(a_Seed + 4000),
 	m_BiomeGen(a_BiomeGen),
 	m_UnderlyingHeiGen(new cHeiGenBiomal(a_Seed, a_BiomeGen)),
 	m_HeightGen(m_UnderlyingHeiGen, 64),
@@ -293,8 +134,6 @@ cDistortedHeightmap::cDistortedHeightmap(int a_Seed, cBiomeGenPtr a_BiomeGen) :
 	m_NoiseDistortZ.AddOctave((NOISE_DATATYPE)1,    (NOISE_DATATYPE)0.5);
 	m_NoiseDistortZ.AddOctave((NOISE_DATATYPE)0.5,  (NOISE_DATATYPE)1);
 	m_NoiseDistortZ.AddOctave((NOISE_DATATYPE)0.25, (NOISE_DATATYPE)2);
-	
-	InitMesaPattern(a_Seed);
 }
 
 
@@ -309,7 +148,7 @@ void cDistortedHeightmap::Initialize(cIniFile & a_IniFile)
 	}
 
 	// Read the params from the INI file:
-	m_SeaLevel   =                 a_IniFile.GetValueSetI("Generator", "DistortedHeightmapSeaLevel",   62);
+	m_SeaLevel   =                 a_IniFile.GetValueSetI("Generator", "SeaLevel",                     62);
 	m_FrequencyX = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "DistortedHeightmapFrequencyX", 10);
 	m_FrequencyY = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "DistortedHeightmapFrequencyY", 10);
 	m_FrequencyZ = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "DistortedHeightmapFrequencyZ", 10);
@@ -321,89 +160,6 @@ void cDistortedHeightmap::Initialize(cIniFile & a_IniFile)
 
 
 
-void cDistortedHeightmap::InitMesaPattern(int a_Seed)
-{
-	// Stone in the bottom half of the pattern:
-	for (int i = cChunkDef::Height; i < 2 * cChunkDef::Height; i++)
-	{
-		m_MesaPattern[i].BlockMeta = 0;
-		m_MesaPattern[i].BlockType = E_BLOCK_STONE;
-	}
-
-	// Stained and hardened clay in the top half of the pattern
-	// In a loop, choose whether to use one or two layers of stained clay, then choose a color and width for each layer
-	// Separate each group with another layer of hardened clay
-	cNoise PatternNoise((unsigned)a_Seed);
-	static NIBBLETYPE AllowedColors[] =
-	{
-		E_META_STAINED_CLAY_YELLOW,
-		E_META_STAINED_CLAY_YELLOW,
-		E_META_STAINED_CLAY_RED,
-		E_META_STAINED_CLAY_RED,
-		E_META_STAINED_CLAY_WHITE,
-		E_META_STAINED_CLAY_BROWN,
-		E_META_STAINED_CLAY_BROWN,
-		E_META_STAINED_CLAY_BROWN,
-		E_META_STAINED_CLAY_ORANGE,
-		E_META_STAINED_CLAY_ORANGE,
-		E_META_STAINED_CLAY_ORANGE,
-		E_META_STAINED_CLAY_ORANGE,
-		E_META_STAINED_CLAY_ORANGE,
-		E_META_STAINED_CLAY_ORANGE,
-		E_META_STAINED_CLAY_LIGHTGRAY,
-	} ;
-	static int LayerSizes[] =  // Adjust the chance so that thinner layers occur more commonly
-	{
-		1, 1, 1, 1, 1, 1,
-		2, 2, 2, 2,
-		3, 3,
-	} ;
-	int Idx = cChunkDef::Height - 1;
-	while (Idx >= 0)
-	{
-		// A layer group of 1 - 2 color stained clay:
-		int Random = PatternNoise.IntNoise1DInt(Idx) / 7;
-		int NumLayers = (Random % 2) + 1;
-		Random /= 2;
-		for (int Lay = 0; Lay < NumLayers; Lay++)
-		{
-			int NumBlocks = LayerSizes[(Random % ARRAYCOUNT(LayerSizes))];
-			NIBBLETYPE Color = AllowedColors[(Random / 4) % ARRAYCOUNT(AllowedColors)];
-			if (
-				((NumBlocks == 3) && (NumLayers == 2)) ||  // In two-layer mode disallow the 3-high layers:
-				(Color == E_META_STAINED_CLAY_WHITE))      // White stained clay can ever be only 1 block high
-			{
-				NumBlocks = 1;
-			}
-			NumBlocks = std::min(Idx + 1, NumBlocks);  // Limit by Idx so that we don't have to check inside the loop
-			Random /= 32;
-			for (int Block = 0; Block < NumBlocks; Block++, Idx--)
-			{
-				m_MesaPattern[Idx].BlockMeta = Color;
-				m_MesaPattern[Idx].BlockType = E_BLOCK_STAINED_CLAY;
-			}  // for Block
-		}  // for Lay
-
-		// A layer of hardened clay in between the layer group:
-		int NumBlocks = (Random % 4) + 1;  // All heights the same probability
-		if ((NumLayers == 2) && (NumBlocks < 4))
-		{
-			// For two layers of stained clay, add an extra block of hardened clay:
-			NumBlocks++;
-		}
-		NumBlocks = std::min(Idx + 1, NumBlocks);  // Limit by Idx so that we don't have to check inside the loop
-		for (int Block = 0; Block < NumBlocks; Block++, Idx--)
-		{
-			m_MesaPattern[Idx].BlockMeta = 0;
-			m_MesaPattern[Idx].BlockType = E_BLOCK_HARDENED_CLAY;
-		}  // for Block
-	}  // while (Idx >= 0)
-}
-
-
-
-
-
 void cDistortedHeightmap::PrepareState(int a_ChunkX, int a_ChunkZ)
 {
 	if ((m_CurChunkX == a_ChunkX) && (m_CurChunkZ == a_ChunkZ))
@@ -474,23 +230,17 @@ void cDistortedHeightmap::GenerateHeightArray(void)
 
 
 
-void cDistortedHeightmap::GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap)
+void cDistortedHeightmap::GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape)
 {
 	PrepareState(a_ChunkX, a_ChunkZ);
 	for (int z = 0; z < cChunkDef::Width; z++)
 	{
 		for (int x = 0; x < cChunkDef::Width; x++)
 		{
-			int NoiseArrayIdx = x + 17 * 257 * z;
-			cChunkDef::SetHeight(a_HeightMap, x, z, m_SeaLevel - 1);
-			for (int y = cChunkDef::Height - 1; y > m_SeaLevel - 1; y--)
+			int idx = x + 17 * 257 * z;
+			for (int y = 0; y < cChunkDef::Height; y++)
 			{
-				int HeightMapHeight = (int)m_DistortedHeightmap[NoiseArrayIdx + 17 * y];
-				if (y < HeightMapHeight)
-				{
-					cChunkDef::SetHeight(a_HeightMap, x, z, y);
-					break;
-				}
+				a_Shape[y + x * 256 + z * 16 * 256] = (y < m_DistortedHeightmap[idx + y * 17]) ? 1 : 0;
 			}  // for y
 		}  // for x
 	}  // for z
@@ -500,36 +250,7 @@ void cDistortedHeightmap::GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::He
 
 
 
-void cDistortedHeightmap::InitializeHeightGen(cIniFile & a_IniFile)
-{
-	Initialize(a_IniFile);
-}
-
-
-
-
-
-void cDistortedHeightmap::ComposeTerrain(cChunkDesc & a_ChunkDesc)
-{
-	// Prepare the internal state for generating this chunk:
-	PrepareState(a_ChunkDesc.GetChunkX(), a_ChunkDesc.GetChunkZ());
-
-	// Compose:
-	a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
-	for (int z = 0; z < cChunkDef::Width; z++)
-	{
-		for (int x = 0; x < cChunkDef::Width; x++)
-		{
-			ComposeColumn(a_ChunkDesc, x, z);
-		}  // for x
-	}  // for z
-}
-
-
-
-
-
-void cDistortedHeightmap::InitializeCompoGen(cIniFile & a_IniFile)
+void cDistortedHeightmap::InitializeShapeGen(cIniFile & a_IniFile)
 {
 	Initialize(a_IniFile);
 }
@@ -654,275 +375,3 @@ void cDistortedHeightmap::GetDistortAmpsAt(BiomeNeighbors & a_Neighbors, int a_R
 
 
 
-void cDistortedHeightmap::ComposeColumn(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ)
-{
-	// Frequencies for the podzol floor selecting noise:
-	const NOISE_DATATYPE FrequencyX = 8;
-	const NOISE_DATATYPE FrequencyZ = 8;
-	
-	EMCSBiome Biome = a_ChunkDesc.GetBiome(a_RelX, a_RelZ);
-	switch (Biome)
-	{
-		case biOcean:
-		case biPlains:
-		case biForest:
-		case biTaiga:
-		case biSwampland:
-		case biRiver:
-		case biFrozenOcean:
-		case biFrozenRiver:
-		case biIcePlains:
-		case biIceMountains:
-		case biForestHills:
-		case biTaigaHills:
-		case biExtremeHillsEdge:
-		case biExtremeHillsPlus:
-		case biExtremeHills:
-		case biJungle:
-		case biJungleHills:
-		case biJungleEdge:
-		case biDeepOcean:
-		case biStoneBeach:
-		case biColdBeach:
-		case biBirchForest:
-		case biBirchForestHills:
-		case biRoofedForest:
-		case biColdTaiga:
-		case biColdTaigaHills:
-		case biSavanna:
-		case biSavannaPlateau:
-		case biSunflowerPlains:
-		case biFlowerForest:
-		case biTaigaM:
-		case biSwamplandM:
-		case biIcePlainsSpikes:
-		case biJungleM:
-		case biJungleEdgeM:
-		case biBirchForestM:
-		case biBirchForestHillsM:
-		case biRoofedForestM:
-		case biColdTaigaM:
-		case biSavannaM:
-		case biSavannaPlateauM:
-		{
-			FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, patGrass.Get());
-			return;
-		}
-
-		case biMegaTaiga:
-		case biMegaTaigaHills:
-		case biMegaSpruceTaiga:
-		case biMegaSpruceTaigaHills:
-		{
-			// Select the pattern to use - podzol, grass or grassless dirt:
-			NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(m_CurChunkX * cChunkDef::Width + a_RelX)) / FrequencyX;
-			NOISE_DATATYPE NoiseY = ((NOISE_DATATYPE)(m_CurChunkZ * cChunkDef::Width + a_RelZ)) / FrequencyZ;
-			NOISE_DATATYPE Val = m_OceanFloorSelect.CubicNoise2D(NoiseX, NoiseY);
-			const sBlockInfo * Pattern = (Val < -0.9) ? patGrassLess.Get() : ((Val > 0) ? patPodzol.Get() : patGrass.Get());
-			FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, Pattern);
-			return;
-		}
-
-		case biDesertHills:
-		case biDesert:
-		case biDesertM:
-		case biBeach:
-		{
-			FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, patSand.Get());
-			return;
-		}
-		
-		case biMushroomIsland:
-		case biMushroomShore:
-		{
-			FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, patMycelium.Get());
-			return;
-		}
-
-		case biMesa:
-		case biMesaPlateauF:
-		case biMesaPlateau:
-		case biMesaBryce:
-		case biMesaPlateauFM:
-		case biMesaPlateauM:
-		{
-			// Mesa biomes need special handling, because they don't follow the usual "4 blocks from top pattern",
-			// instead, they provide a "from bottom" pattern with varying base height,
-			// usually 4 blocks below the ocean level
-			FillColumnMesa(a_ChunkDesc, a_RelX, a_RelZ);
-			return;
-		}
-
-		case biExtremeHillsPlusM:
-		case biExtremeHillsM:
-		{
-			// Select the pattern to use - gravel, stone or grass:
-			NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(m_CurChunkX * cChunkDef::Width + a_RelX)) / FrequencyX;
-			NOISE_DATATYPE NoiseY = ((NOISE_DATATYPE)(m_CurChunkZ * cChunkDef::Width + a_RelZ)) / FrequencyZ;
-			NOISE_DATATYPE Val = m_OceanFloorSelect.CubicNoise2D(NoiseX, NoiseY);
-			const sBlockInfo * Pattern = (Val < 0.0) ? patStone.Get() : patGrass.Get();
-			FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, Pattern);
-			return;
-		}
-		default:
-		{
-			ASSERT(!"Unhandled biome");
-			return;
-		}
-	}  // switch (Biome)
-}
-
-
-
-
-
-void cDistortedHeightmap::FillColumnPattern(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ, const sBlockInfo * a_Pattern)
-{
-	int NoiseArrayIdx = a_RelX + 17 * 257 * a_RelZ;
-	bool HasHadWater = false;
-	int PatternIdx = 0;
-	for (int y = a_ChunkDesc.GetHeight(a_RelX, a_RelZ); y > 0; y--)
-	{
-		int HeightMapHeight = (int)m_DistortedHeightmap[NoiseArrayIdx + 17 * y];
-
-		if (y < HeightMapHeight)
-		{
-			// "ground" part, use the pattern:
-			a_ChunkDesc.SetBlockTypeMeta(a_RelX, y, a_RelZ, a_Pattern[PatternIdx].BlockType, a_Pattern[PatternIdx].BlockMeta);
-			PatternIdx++;
-			continue;
-		}
-		
-		// "air" or "water" part:
-		// Reset the pattern index to zero, so that the pattern is repeated from the top again:
-		PatternIdx = 0;
-		
-		if (y >= m_SeaLevel)
-		{
-			// "air" part, do nothing
-			continue;
-		}
-		
-		a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_STATIONARY_WATER);
-		if (HasHadWater)
-		{
-			continue;
-		}
-		
-		// Select the ocean-floor pattern to use:
-		a_Pattern = a_ChunkDesc.GetBiome(a_RelX, a_RelZ) == biDeepOcean ? patGravel.Get() : ChooseOceanFloorPattern(a_RelX, a_RelZ);
-		HasHadWater = true;
-	}  // for y
-	a_ChunkDesc.SetBlockType(a_RelX, 0, a_RelZ, E_BLOCK_BEDROCK);
-}
-
-
-
-
-
-void cDistortedHeightmap::FillColumnMesa(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ)
-{
-	// Frequencies for the clay floor noise:
-	const NOISE_DATATYPE FrequencyX = 50;
-	const NOISE_DATATYPE FrequencyZ = 50;
-
-	int Top = a_ChunkDesc.GetHeight(a_RelX, a_RelZ);
-	if (Top < m_SeaLevel)
-	{
-		// The terrain is below sealevel, handle as regular ocean:
-		FillColumnPattern(a_ChunkDesc, a_RelX, a_RelZ, patOFRedSand.Get());
-		return;
-	}
-
-	NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(m_CurChunkX * cChunkDef::Width + a_RelX)) / FrequencyX;
-	NOISE_DATATYPE NoiseY = ((NOISE_DATATYPE)(m_CurChunkZ * cChunkDef::Width + a_RelZ)) / FrequencyZ;
-	int ClayFloor = m_SeaLevel - 6 + (int)(4.f * m_MesaFloor.CubicNoise2D(NoiseX, NoiseY));
-	if (ClayFloor >= Top)
-	{
-		ClayFloor = Top - 1;
-	}
-	
-	if (Top - m_SeaLevel < 5)
-	{
-		// Simple case: top is red sand, then hardened clay down to ClayFloor, then stone:
-		a_ChunkDesc.SetBlockTypeMeta(a_RelX, Top, a_RelZ, E_BLOCK_SAND, E_META_SAND_RED);
-		for (int y = Top - 1; y >= ClayFloor; y--)
-		{
-			a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_HARDENED_CLAY);
-		}
-		for (int y = ClayFloor - 1; y > 0; y--)
-		{
-			a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_STONE);
-		}
-		a_ChunkDesc.SetBlockType(a_RelX, 0, a_RelZ, E_BLOCK_BEDROCK);
-		return;
-	}
-	
-	// Difficult case: use the mesa pattern and watch for overhangs:
-	int NoiseArrayIdx = a_RelX + 17 * 257 * a_RelZ;
-	int PatternIdx = cChunkDef::Height - (Top - ClayFloor);  // We want the block at index ClayFloor to be pattern's 256th block (first stone)
-	const sBlockInfo * Pattern = m_MesaPattern;
-	bool HasHadWater = false;
-	for (int y = Top; y > 0; y--)
-	{
-		int HeightMapHeight = (int)m_DistortedHeightmap[NoiseArrayIdx + 17 * y];
-		if (y < HeightMapHeight)
-		{
-			// "ground" part, use the pattern:
-			a_ChunkDesc.SetBlockTypeMeta(a_RelX, y, a_RelZ, Pattern[PatternIdx].BlockType, Pattern[PatternIdx].BlockMeta);
-			PatternIdx++;
-			continue;
-		}
-
-		if (y >= m_SeaLevel)
-		{
-			// "air" part, do nothing
-			continue;
-		}
-		
-		// "water" part, fill with water and choose new pattern for ocean floor, if not chosen already:
-		PatternIdx = 0;
-		a_ChunkDesc.SetBlockType(a_RelX, y, a_RelZ, E_BLOCK_STATIONARY_WATER);
-		if (HasHadWater)
-		{
-			continue;
-		}
-		
-		// Select the ocean-floor pattern to use:
-		Pattern = ChooseOceanFloorPattern(a_RelX, a_RelZ);
-		HasHadWater = true;
-	}  // for y
-	a_ChunkDesc.SetBlockType(a_RelX, 0, a_RelZ, E_BLOCK_BEDROCK);
-}
-
-
-
-
-
-const cDistortedHeightmap::sBlockInfo * cDistortedHeightmap::ChooseOceanFloorPattern(int a_RelX, int a_RelZ)
-{
-	// Frequencies for the ocean floor selecting noise:
-	const NOISE_DATATYPE FrequencyX = 3;
-	const NOISE_DATATYPE FrequencyZ = 3;
-
-	// Select the ocean-floor pattern to use:
-	NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(m_CurChunkX * cChunkDef::Width + a_RelX)) / FrequencyX;
-	NOISE_DATATYPE NoiseY = ((NOISE_DATATYPE)(m_CurChunkZ * cChunkDef::Width + a_RelZ)) / FrequencyZ;
-	NOISE_DATATYPE Val = m_OceanFloorSelect.CubicNoise2D(NoiseX, NoiseY);
-	if (Val < -0.95)
-	{
-		return patOFClay.Get();
-	}
-	else if (Val < 0)
-	{
-		return patOFSand.Get();
-	}
-	else
-	{
-		return patDirt.Get();
-	}
-}
-
-
-
-
diff --git a/src/Generating/DistortedHeightmap.h b/src/Generating/DistortedHeightmap.h
index 955e57a1e..79fc35542 100644
--- a/src/Generating/DistortedHeightmap.h
+++ b/src/Generating/DistortedHeightmap.h
@@ -23,17 +23,9 @@
 
 
 class cDistortedHeightmap :
-	public cTerrainHeightGen,
-	public cTerrainCompositionGen
+	public cTerrainShapeGen
 {
 public:
-	/// Structure used for storing block patterns for columns
-	struct sBlockInfo
-	{
-		BLOCKTYPE  BlockType;
-		NIBBLETYPE BlockMeta;
-	} ;
-
 	cDistortedHeightmap(int a_Seed, cBiomeGenPtr a_BiomeGen);
 	
 protected:
@@ -51,8 +43,6 @@ protected:
 
 	cPerlinNoise m_NoiseDistortX;
 	cPerlinNoise m_NoiseDistortZ;
-	cNoise       m_OceanFloorSelect;  ///< Used for selecting between dirt and sand on the ocean floor
-	cNoise       m_MesaFloor;         ///< Used for the floor of the clay blocks in mesa biomes
 
 	int m_SeaLevel;
 	NOISE_DATATYPE m_FrequencyX;
@@ -70,9 +60,9 @@ protected:
 	cTerrainHeightGenPtr m_UnderlyingHeiGen;
 
 	/** Cache for m_UnderlyingHeiGen. */
-	cHeiGenCache  m_HeightGen;
+	cHeiGenCache m_HeightGen;
 	
-	/// Heightmap for the current chunk, before distortion (from m_HeightGen). Used for optimization.
+	/** Heightmap for the current chunk, before distortion (from m_HeightGen). Used for optimization. */
 	cChunkDef::HeightMap m_CurChunkHeights;
 	
 	// Per-biome terrain generator parameters:
@@ -87,54 +77,30 @@ protected:
 	NOISE_DATATYPE m_DistortAmpX[DIM_X * DIM_Z];
 	NOISE_DATATYPE m_DistortAmpZ[DIM_X * DIM_Z];
 	
-	/// True if Initialize() has been called. Used to initialize-once even with multiple init entrypoints (HeiGen / CompoGen)
+	/** True if Initialize() has been called. Used to initialize-once even with multiple init entrypoints (HeiGen / CompoGen). */
 	bool m_IsInitialized;
 	
-	/// The vertical pattern to be used for mesa biomes. Seed-dependant.
-	/// One Height of pattern and one Height of stone to avoid checking pattern dimensions
-	sBlockInfo m_MesaPattern[2 * cChunkDef::Height];
-	
 
-	/// Initializes m_MesaPattern with a reasonable pattern of stained clay / hardened clay, based on the seed
-	void InitMesaPattern(int a_Seed);
-	
-	/// Unless the LastChunk coords are equal to coords given, prepares the internal state (noise arrays, heightmap)
+	/** Unless the LastChunk coords are equal to coords given, prepares the internal state (noise arrays, heightmap). */
 	void PrepareState(int a_ChunkX, int a_ChunkZ);
 	
-	/// Generates the m_DistortedHeightmap array for the current chunk
+	/** Generates the m_DistortedHeightmap array for the current chunk. */
 	void GenerateHeightArray(void);
 	
-	/// Calculates the heightmap value (before distortion) at the specified (floating-point) coords
+	/** Calculates the heightmap value (before distortion) at the specified (floating-point) coords. */
 	int GetHeightmapAt(NOISE_DATATYPE a_X, NOISE_DATATYPE a_Z);
 	
-	/// Updates m_DistortAmpX/Z[] based on m_CurChunkX and m_CurChunkZ
+	/** Updates m_DistortAmpX/Z[] based on m_CurChunkX and m_CurChunkZ. */
 	void UpdateDistortAmps(void);
 	
-	/// Calculates the X and Z distortion amplitudes based on the neighbors' biomes
+	/** Calculates the X and Z distortion amplitudes based on the neighbors' biomes. */
 	void GetDistortAmpsAt(BiomeNeighbors & a_Neighbors, int a_RelX, int a_RelZ, NOISE_DATATYPE & a_DistortAmpX, NOISE_DATATYPE & a_DistortAmpZ);
 	
-	/// Reads the settings from the ini file. Skips reading if already initialized
+	/** Reads the settings from the ini file. Skips reading if already initialized. */
 	void Initialize(cIniFile & a_IniFile);
 	
-	/// Composes a single column in a_ChunkDesc. Chooses what to do based on the biome in that column
-	void ComposeColumn(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ);
 	
-	/// Fills the specified column with the specified pattern; restarts the pattern when air is reached,
-	/// switches to ocean floor pattern if ocean is reached. Always adds bedrock at the very bottom.
-	void FillColumnPattern(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ, const sBlockInfo * a_Pattern);
-	
-	/// Fills the specified column with mesa pattern, based on the column height
-	void FillColumnMesa(cChunkDesc & a_ChunkDesc, int a_RelX, int a_RelZ);
-	
-	/// Returns the pattern to use for an ocean floor in the specified column
-	const sBlockInfo * ChooseOceanFloorPattern(int a_RelX, int a_RelZ);
-	
-	
-	// cTerrainHeightGen overrides:
-	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
-	virtual void InitializeHeightGen(cIniFile & a_IniFile) override;
-
-	// cTerrainCompositionGen overrides:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
-	virtual void InitializeCompoGen(cIniFile & a_IniFile) override;
+	// cTerrainShapeGen overrides:
+	virtual void GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape) override;
+	virtual void InitializeShapeGen(cIniFile & a_IniFile) override;
 } ;
diff --git a/src/Generating/DungeonRoomsFinisher.cpp b/src/Generating/DungeonRoomsFinisher.cpp
index 3f328868d..7ab22c2c5 100644
--- a/src/Generating/DungeonRoomsFinisher.cpp
+++ b/src/Generating/DungeonRoomsFinisher.cpp
@@ -78,7 +78,8 @@ protected:
 
 
 
-	/** Decodes the position index along the room walls into a proper 2D position for a chest. */
+	/** Decodes the position index along the room walls into a proper 2D position for a chest.
+	The Y coord of the returned vector specifies the chest's meta value*/
 	Vector3i DecodeChestCoords(int a_PosIdx, int a_SizeX, int a_SizeZ)
 	{
 		if (a_PosIdx < a_SizeX)
@@ -258,9 +259,9 @@ protected:
 ////////////////////////////////////////////////////////////////////////////////
 // cDungeonRoomsFinisher:
 
-cDungeonRoomsFinisher::cDungeonRoomsFinisher(cTerrainHeightGenPtr a_HeightGen, int a_Seed, int a_GridSize, int a_MaxSize, int a_MinSize, const AString & a_HeightDistrib) :
+cDungeonRoomsFinisher::cDungeonRoomsFinisher(cTerrainShapeGenPtr a_ShapeGen, int a_Seed, int a_GridSize, int a_MaxSize, int a_MinSize, const AString & a_HeightDistrib) :
 	super(a_Seed + 100, a_GridSize, a_GridSize, a_GridSize, a_GridSize, a_MaxSize, a_MaxSize, 1024),
-	m_HeightGen(a_HeightGen),
+	m_ShapeGen(a_ShapeGen),
 	m_MaxHalfSize((a_MaxSize + 1) / 2),
 	m_MinHalfSize((a_MinSize + 1) / 2),
 	m_HeightProbability(cChunkDef::Height)
@@ -293,13 +294,21 @@ cDungeonRoomsFinisher::cStructurePtr cDungeonRoomsFinisher::CreateStructure(int
 	int ChunkX, ChunkZ;
 	int RelX = a_OriginX, RelY = 0, RelZ = a_OriginZ;
 	cChunkDef::AbsoluteToRelative(RelX, RelY, RelZ, ChunkX, ChunkZ);
-	cChunkDef::HeightMap HeightMap;
-	m_HeightGen->GenHeightMap(ChunkX, ChunkZ, HeightMap);
-	int Height = cChunkDef::GetHeight(HeightMap, RelX, RelZ);  // Max room height at {a_OriginX, a_OriginZ}
-	Height = Clamp(m_HeightProbability.MapValue(rnd % m_HeightProbability.GetSum()), 10, Height - 5);
+	cChunkDesc::Shape shape;
+	m_ShapeGen->GenShape(ChunkX, ChunkZ, shape);
+	int height = 0;
+	int idx = RelX * 256 + RelZ * 16 * 256;
+	for (int y = 6; y < cChunkDef::Height; y++)
+	{
+		if (shape[idx + y] != 0)
+		{
+			continue;
+		}
+		height = Clamp(m_HeightProbability.MapValue(rnd % m_HeightProbability.GetSum()), 10, y - 5);
+	}
 
 	// Create the dungeon room descriptor:
-	return cStructurePtr(new cDungeonRoom(a_GridX, a_GridZ, a_OriginX, a_OriginZ, HalfSizeX, HalfSizeZ, Height, m_Noise));
+	return cStructurePtr(new cDungeonRoom(a_GridX, a_GridZ, a_OriginX, a_OriginZ, HalfSizeX, HalfSizeZ, height, m_Noise));
 }
 
 
diff --git a/src/Generating/DungeonRoomsFinisher.h b/src/Generating/DungeonRoomsFinisher.h
index 09dd0448a..e5828f989 100644
--- a/src/Generating/DungeonRoomsFinisher.h
+++ b/src/Generating/DungeonRoomsFinisher.h
@@ -23,15 +23,15 @@ class cDungeonRoomsFinisher :
 
 public:
 	/** Creates a new dungeon room finisher.
-	a_HeightGen is the underlying height generator, so that the rooms can always be placed under the terrain.
+	a_ShapeGen is the underlying terrain shape generator, so that the rooms can always be placed under the terrain.
 	a_MaxSize and a_MinSize are the maximum and minimum sizes of the room's internal (air) area, in blocks across.
 	a_HeightDistrib is the string defining the height distribution for the rooms (cProbabDistrib format). */
-	cDungeonRoomsFinisher(cTerrainHeightGenPtr a_HeightGen, int a_Seed, int a_GridSize, int a_MaxSize, int a_MinSize, const AString & a_HeightDistrib);
+	cDungeonRoomsFinisher(cTerrainShapeGenPtr a_ShapeGen, int a_Seed, int a_GridSize, int a_MaxSize, int a_MinSize, const AString & a_HeightDistrib);
 
 protected:
 
-	/** The height gen that is used for limiting the rooms' Y coords */
-	cTerrainHeightGenPtr m_HeightGen;
+	/** The shape gen that is used for limiting the rooms' Y coords */
+	cTerrainShapeGenPtr m_ShapeGen;
 
 	/** Maximum half-size (from center to wall) of the dungeon room's inner (air) area. Default is 3 (vanilla). */
 	int m_MaxHalfSize;
diff --git a/src/Generating/EndGen.cpp b/src/Generating/EndGen.cpp
index 0111d2fa3..89d6117bb 100644
--- a/src/Generating/EndGen.cpp
+++ b/src/Generating/EndGen.cpp
@@ -147,13 +147,14 @@ bool cEndGen::IsChunkOutsideRange(int a_ChunkX, int a_ChunkZ)
 
 
 
-void cEndGen::GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap)
+void cEndGen::GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape)
 {
+	// If the chunk is outside out range, fill the shape with zeroes:
 	if (IsChunkOutsideRange(a_ChunkX, a_ChunkZ))
 	{
-		for (size_t i = 0; i < ARRAYCOUNT(a_HeightMap); i++)
+		for (size_t i = 0; i < ARRAYCOUNT(a_Shape); i++)
 		{
-			a_HeightMap[i] = 0;
+			a_Shape[i] = 0;
 		}
 		return;
 	}
@@ -165,15 +166,14 @@ void cEndGen::GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_
 	{
 		for (int x = 0; x < cChunkDef::Width; x++)
 		{
-			cChunkDef::SetHeight(a_HeightMap, x, z, MaxY);
-			for (int y = MaxY; y > 0; y--)
+			for (int y = 0; y < MaxY; y++)
 			{
-				if (m_NoiseArray[y * 17 * 17 + z * 17 + x] <= 0)
-				{
-					cChunkDef::SetHeight(a_HeightMap, x, z, y);
-					break;
-				}
-			}  // for y
+				a_Shape[(x + 16 * z) * 256 + y] = (m_NoiseArray[y * 17 * 17 + z * 17 + z] > 0) ? 1 : 0;
+			}
+			for (int y = MaxY; y < cChunkDef::Height; y++)
+			{
+				a_Shape[(x + 16 * z) * 256 + y] = 0;
+			}
 		}  // for x
 	}  // for z
 }
@@ -182,30 +182,18 @@ void cEndGen::GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_
 
 
 
-void cEndGen::ComposeTerrain(cChunkDesc & a_ChunkDesc)
+void cEndGen::ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape)
 {
-	if (IsChunkOutsideRange(a_ChunkDesc.GetChunkX(), a_ChunkDesc.GetChunkZ()))
-	{
-		a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
-		return;
-	}
-
-	PrepareState(a_ChunkDesc.GetChunkX(), a_ChunkDesc.GetChunkZ());
-
-	int MaxY = std::min((int)(1.75 * m_IslandSizeY + 1), cChunkDef::Height - 1);
+	a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
 	for (int z = 0; z < cChunkDef::Width; z++)
 	{
 		for (int x = 0; x < cChunkDef::Width; x++)
 		{
-			for (int y = MaxY; y > 0; y--)
+			for (int y = 0; y < cChunkDef::Height; y++)
 			{
-				if (m_NoiseArray[y * 17 * 17 + z * 17 + x] <= 0)
-				{
-					a_ChunkDesc.SetBlockTypeMeta(x, y, z, E_BLOCK_END_STONE, 0);
-				}
-				else
+				if (a_Shape[(x + 16 * z) * 256 + y] != 0)
 				{
-					a_ChunkDesc.SetBlockTypeMeta(x, y, z, E_BLOCK_AIR, 0);
+					a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_END_STONE);
 				}
 			}  // for y
 		}  // for x
diff --git a/src/Generating/EndGen.h b/src/Generating/EndGen.h
index c2278c1e1..f9e3f6e53 100644
--- a/src/Generating/EndGen.h
+++ b/src/Generating/EndGen.h
@@ -17,7 +17,7 @@
 
 
 class cEndGen :
-	public cTerrainHeightGen,
+	public cTerrainShapeGen,
 	public cTerrainCompositionGen
 {
 public:
@@ -59,10 +59,10 @@ protected:
 	/// Returns true if the chunk is outside of the island's dimensions
 	bool IsChunkOutsideRange(int a_ChunkX, int a_ChunkZ);
 		
-	// cTerrainHeightGen overrides:
-	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
+	// cTerrainShapeGen overrides:
+	virtual void GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape) override;
 
 	// cTerrainCompositionGen overrides:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
+	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc, const cChunkDesc::Shape & a_Shape) override;
 	virtual void InitializeCompoGen(cIniFile & a_IniFile) override;
 } ;
diff --git a/src/Generating/FinishGen.cpp b/src/Generating/FinishGen.cpp
index 42ecdf8a8..2ff3e7f67 100644
--- a/src/Generating/FinishGen.cpp
+++ b/src/Generating/FinishGen.cpp
@@ -411,7 +411,7 @@ void cFinishGenSnow::GenFinish(cChunkDesc & a_ChunkDesc)
 				case biFrozenOcean:
 				{
 					int Height = a_ChunkDesc.GetHeight(x, z);
-					if (cBlockInfo::IsSnowable(a_ChunkDesc.GetBlockType(x, Height, z)))
+					if (cBlockInfo::IsSnowable(a_ChunkDesc.GetBlockType(x, Height, z)) && (Height < cChunkDef::Height - 1))
 					{
 						a_ChunkDesc.SetBlockType(x, Height + 1, z, E_BLOCK_SNOW);
 						a_ChunkDesc.SetHeight(x, z, Height + 1);
diff --git a/src/Generating/HeiGen.cpp b/src/Generating/HeiGen.cpp
index 1d9f1e3aa..61d087c17 100644
--- a/src/Generating/HeiGen.cpp
+++ b/src/Generating/HeiGen.cpp
@@ -15,7 +15,6 @@
 
 
 
-
 ////////////////////////////////////////////////////////////////////////////////
 // cHeiGenFlat:
 
@@ -133,15 +132,6 @@ void cHeiGenCache::GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap
 
 
 
-void cHeiGenCache::InitializeHeightGen(cIniFile & a_IniFile)
-{
-	m_HeiGenToCache->InitializeHeightGen(a_IniFile);
-}
-
-
-
-
-
 bool cHeiGenCache::GetHeightAt(int a_ChunkX, int a_ChunkZ, int a_RelX, int a_RelZ, HEIGHTTYPE & a_Height)
 {
 	for (int i = 0; i < m_CacheSize; i++)
@@ -160,6 +150,51 @@ bool cHeiGenCache::GetHeightAt(int a_ChunkX, int a_ChunkZ, int a_RelX, int a_Rel
 
 
 ////////////////////////////////////////////////////////////////////////////////
+// cHeiGenMultiCache:
+
+cHeiGenMultiCache::cHeiGenMultiCache(cTerrainHeightGenPtr a_HeiGenToCache, size_t a_SubCacheSize, size_t a_NumSubCaches):
+	m_NumSubCaches(a_NumSubCaches)
+{
+	// Create the individual sub-caches:
+	m_SubCaches.reserve(a_NumSubCaches);
+	for (size_t i = 0; i < a_NumSubCaches; i++)
+	{
+		m_SubCaches.push_back(std::make_shared<cHeiGenCache>(a_HeiGenToCache, a_SubCacheSize));
+	}
+}
+
+
+
+
+
+void cHeiGenMultiCache::GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap)
+{
+	// Get the subcache responsible for this chunk:
+	const size_t cacheIdx = ((size_t)a_ChunkX + m_CoeffZ * (size_t)a_ChunkZ) % m_NumSubCaches;
+
+	// Ask the subcache:
+	m_SubCaches[cacheIdx]->GenHeightMap(a_ChunkX, a_ChunkZ, a_HeightMap);
+}
+
+
+
+
+
+bool cHeiGenMultiCache::GetHeightAt(int a_ChunkX, int a_ChunkZ, int a_RelX, int a_RelZ, HEIGHTTYPE & a_Height)
+{
+	// Get the subcache responsible for this chunk:
+	const size_t cacheIdx = ((size_t)a_ChunkX + m_CoeffZ * (size_t)a_ChunkZ) % m_NumSubCaches;
+
+	// Ask the subcache:
+	return m_SubCaches[cacheIdx]->GetHeightAt(a_ChunkX, a_ChunkZ, a_RelX, a_RelZ, a_Height);
+}
+
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
 // cHeiGenClassic:
 
 cHeiGenClassic::cHeiGenClassic(int a_Seed) :
@@ -750,43 +785,51 @@ cTerrainHeightGenPtr cTerrainHeightGen::CreateHeightGen(cIniFile & a_IniFile, cB
 	}
 	
 	a_CacheOffByDefault = false;
-	cTerrainHeightGen * res = nullptr;
-	if (NoCaseCompare(HeightGenName, "flat") == 0)
+	cTerrainHeightGenPtr res;
+	if (NoCaseCompare(HeightGenName, "Flat") == 0)
 	{
-		res = new cHeiGenFlat;
+		res = std::make_shared<cHeiGenFlat>();
 		a_CacheOffByDefault = true;  // We're generating faster than a cache would retrieve data
 	}
 	else if (NoCaseCompare(HeightGenName, "classic") == 0)
 	{
-		res = new cHeiGenClassic(a_Seed);
+		res = std::make_shared<cHeiGenClassic>(a_Seed);
 	}
 	else if (NoCaseCompare(HeightGenName, "DistortedHeightmap") == 0)
 	{
-		res = new cDistortedHeightmap(a_Seed, a_BiomeGen);
+		// Not a heightmap-based generator, but it used to be accessible via HeightGen, so we need to skip making the default out of it
+		// Return an empty pointer, the caller will create the proper generator:
+		return cTerrainHeightGenPtr();
 	}
 	else if (NoCaseCompare(HeightGenName, "End") == 0)
 	{
-		res = new cEndGen(a_Seed);
+		// Not a heightmap-based generator, but it used to be accessible via HeightGen, so we need to skip making the default out of it
+		// Return an empty pointer, the caller will create the proper generator:
+		return cTerrainHeightGenPtr();
 	}
 	else if (NoCaseCompare(HeightGenName, "MinMax") == 0)
 	{
-		res = new cHeiGenMinMax(a_Seed, a_BiomeGen);
+		res = std::make_shared<cHeiGenMinMax>(a_Seed, a_BiomeGen);
 	}
 	else if (NoCaseCompare(HeightGenName, "Mountains") == 0)
 	{
-		res = new cHeiGenMountains(a_Seed);
+		res = std::make_shared<cHeiGenMountains>(a_Seed);
 	}
 	else if (NoCaseCompare(HeightGenName, "BiomalNoise3D") == 0)
 	{
-		res = new cBiomalNoise3DComposable(a_Seed, a_BiomeGen);
+		// Not a heightmap-based generator, but it used to be accessible via HeightGen, so we need to skip making the default out of it
+		// Return an empty pointer, the caller will create the proper generator:
+		return cTerrainHeightGenPtr();
 	}
 	else if (NoCaseCompare(HeightGenName, "Noise3D") == 0)
 	{
-		res = new cNoise3DComposable(a_Seed);
+		// Not a heightmap-based generator, but it used to be accessible via HeightGen, so we need to skip making the default out of it
+		// Return an empty pointer, the caller will create the proper generator:
+		return cTerrainHeightGenPtr();
 	}
-	else if (NoCaseCompare(HeightGenName, "biomal") == 0)
+	else if (NoCaseCompare(HeightGenName, "Biomal") == 0)
 	{
-		res = new cHeiGenBiomal(a_Seed, a_BiomeGen);
+		res = std::make_shared<cHeiGenBiomal>(a_Seed, a_BiomeGen);
 
 		/*
 		// Performance-testing:
@@ -805,15 +848,14 @@ cTerrainHeightGenPtr cTerrainHeightGen::CreateHeightGen(cIniFile & a_IniFile, cB
 	{
 		// No match found, force-set the default and retry
 		LOGWARN("Unknown HeightGen \"%s\", using \"Biomal\" instead.", HeightGenName.c_str());
-		a_IniFile.DeleteValue("Generator", "HeightGen");
 		a_IniFile.SetValue("Generator", "HeightGen", "Biomal");
 		return CreateHeightGen(a_IniFile, a_BiomeGen, a_Seed, a_CacheOffByDefault);
 	}
 	
 	// Read the settings:
 	res->InitializeHeightGen(a_IniFile);
-	
-	return cTerrainHeightGenPtr(res);
+
+	return res;
 }
 
 
diff --git a/src/Generating/HeiGen.h b/src/Generating/HeiGen.h
index b3c9483fb..62bb227c6 100644
--- a/src/Generating/HeiGen.h
+++ b/src/Generating/HeiGen.h
@@ -2,10 +2,12 @@
 // HeiGen.h
 
 /*
-Interfaces to the various height generators:
+Interfaces to the various height-based terrain shape generators:
 	- cHeiGenFlat
 	- cHeiGenClassic
 	- cHeiGenBiomal
+
+Also implements the heightmap cache
 */
 
 
@@ -21,26 +23,7 @@ Interfaces to the various height generators:
 
 
 
-class cHeiGenFlat :
-	public cTerrainHeightGen
-{
-public:
-	cHeiGenFlat(void) : m_Height(5) {}
-	
-protected:
-
-	int m_Height;
-
-	// cTerrainHeightGen overrides:
-	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
-	virtual void InitializeHeightGen(cIniFile & a_IniFile) override;
-} ;
-
-
-
-
-
-/// A simple cache that stores N most recently generated chunks' heightmaps; N being settable upon creation
+/** A simple cache that stores N most recently generated chunks' heightmaps; N being settable upon creation */
 class cHeiGenCache :
 	public cTerrainHeightGen
 {
@@ -50,15 +33,11 @@ public:
 	
 	// cTerrainHeightGen overrides:
 	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
-	virtual void InitializeHeightGen(cIniFile & a_IniFile) override;
 	
-	/// Retrieves height at the specified point in the cache, returns true if found, false if not found
+	/** Retrieves height at the specified point in the cache, returns true if found, false if not found */
 	bool GetHeightAt(int a_ChunkX, int a_ChunkZ, int a_RelX, int a_RelZ, HEIGHTTYPE & a_Height);
 	
 protected:
-
-	cTerrainHeightGenPtr m_HeiGenToCache;
-	
 	struct sCacheData
 	{
 		int m_ChunkX;
@@ -66,6 +45,9 @@ protected:
 		cChunkDef::HeightMap m_HeightMap;
 	} ;
 	
+	/** The terrain height generator that is being cached. */
+	cTerrainHeightGenPtr m_HeiGenToCache;
+	
 	// To avoid moving large amounts of data for the MRU behavior, we MRU-ize indices to an array of the actual data
 	int          m_CacheSize;
 	int *        m_CacheOrder;  // MRU-ized order, indices into m_CacheData array
@@ -81,6 +63,57 @@ protected:
 
 
 
+/** Caches heightmaps in multiple underlying caches to improve the distribution and lower the chain length. */
+class cHeiGenMultiCache:
+	public cTerrainHeightGen
+{
+public:
+	cHeiGenMultiCache(cTerrainHeightGenPtr a_HeightGenToCache, size_t a_SubCacheSize, size_t a_NumSubCaches);
+
+	// cTerrainHeightGen overrides:
+	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
+	
+	/** Retrieves height at the specified point in the cache, returns true if found, false if not found */
+	bool GetHeightAt(int a_ChunkX, int a_ChunkZ, int a_RelX, int a_RelZ, HEIGHTTYPE & a_Height);
+
+protected:
+	typedef SharedPtr<cHeiGenCache> cHeiGenCachePtr;
+	typedef std::vector<cHeiGenCachePtr> cHeiGenCachePtrs;
+
+
+	/** The coefficient used to turn Z coords into index (x + Coeff * z). */
+	static const size_t m_CoeffZ = 5;
+
+	/** Number of sub-caches, pulled out of m_SubCaches.size() for performance reasons. */
+	size_t m_NumSubCaches;
+
+	/** The individual sub-caches. */
+	cHeiGenCachePtrs m_SubCaches;
+};
+
+
+
+
+
+class cHeiGenFlat :
+	public cTerrainHeightGen
+{
+public:
+	cHeiGenFlat(void) : m_Height(5) {}
+	
+protected:
+
+	int m_Height;
+
+	// cTerrainHeightGen overrides:
+	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
+	virtual void InitializeHeightGen(cIniFile & a_IniFile) override;
+} ;
+
+
+
+
+
 class cHeiGenClassic :
 	public cTerrainHeightGen
 {
@@ -137,7 +170,11 @@ public:
 		m_BiomeGen(a_BiomeGen)
 	{
 	}
-	
+
+	// cTerrainHeightGen overrides:
+	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
+	virtual void InitializeHeightGen(cIniFile & a_IniFile) override;
+
 protected:
 
 	typedef cChunkDef::BiomeMap BiomeNeighbors[3][3];
@@ -154,11 +191,8 @@ protected:
 		float m_BaseHeight;
 	} ;
 	static const sGenParam m_GenParam[256];
-	
-	// cTerrainHeightGen overrides:
-	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
-	virtual void InitializeHeightGen(cIniFile & a_IniFile) override;
-	
+
+
 	NOISE_DATATYPE GetHeightAt(int a_RelX, int a_RelZ, int a_ChunkX, int a_ChunkZ, const BiomeNeighbors & a_BiomeNeighbors);
 } ;
 
diff --git a/src/Generating/Noise3DGenerator.cpp b/src/Generating/Noise3DGenerator.cpp
index 78b739d32..a7af87bac 100644
--- a/src/Generating/Noise3DGenerator.cpp
+++ b/src/Generating/Noise3DGenerator.cpp
@@ -166,69 +166,6 @@ cNoise3DGenerator::cNoise3DGenerator(cChunkGenerator & a_ChunkGenerator) :
 	m_Cubic.AddOctave(4,  0.25);
 	m_Cubic.AddOctave(8,  0.125);
 	m_Cubic.AddOctave(16, 0.0625);
-
-	#if 0
-	// DEBUG: Test the noise generation:
-	// NOTE: In order to be able to run MCS with this code, you need to increase the default thread stack size
-	// In MSVC, it is done in Project Settings -> Configuration Properties -> Linker -> System, set Stack reserve size to at least 64M
-	m_SeaLevel            = 62;
-	m_HeightAmplification = 0;
-	m_MidPoint            = 75;
-	m_FrequencyX          = 4;
-	m_FrequencyY          = 4;
-	m_FrequencyZ          = 4;
-	m_AirThreshold        = 0.5;
-
-	const int NumChunks = 4;
-	NOISE_DATATYPE Noise[NumChunks][cChunkDef::Width * cChunkDef::Width * cChunkDef::Height];
-	for (int x = 0; x < NumChunks; x++)
-	{
-		GenerateNoiseArray(x, 5, Noise[x]);
-	}
-
-	// Save in XY cuts:
-	cFile f1;
-	if (f1.Open("Test_XY.grab", cFile::fmWrite))
-	{
-		for (int z = 0; z < cChunkDef::Width; z++)
-		{
-			for (int y = 0; y < cChunkDef::Height; y++)
-			{
-				for (int i = 0; i < NumChunks; i++)
-				{
-					int idx = y * cChunkDef::Width + z * cChunkDef::Width * cChunkDef::Height;
-					unsigned char buf[cChunkDef::Width];
-					for (int x = 0; x < cChunkDef::Width; x++)
-					{
-						buf[x] = (unsigned char)(std::min(256, std::max(0, (int)(128 + 32 * Noise[i][idx++]))));
-					}
-					f1.Write(buf, cChunkDef::Width);
-				}
-			}  // for y
-		}  // for z
-	}  // if (XY file open)
-
-	cFile f2;
-	if (f2.Open("Test_XZ.grab", cFile::fmWrite))
-	{
-		for (int y = 0; y < cChunkDef::Height; y++)
-		{
-			for (int z = 0; z < cChunkDef::Width; z++)
-			{
-				for (int i = 0; i < NumChunks; i++)
-				{
-					int idx = y * cChunkDef::Width + z * cChunkDef::Width * cChunkDef::Height;
-					unsigned char buf[cChunkDef::Width];
-					for (int x = 0; x < cChunkDef::Width; x++)
-					{
-						buf[x] = (unsigned char)(std::min(256, std::max(0, (int)(128 + 32 * Noise[i][idx++]))));
-					}
-					f2.Write(buf, cChunkDef::Width);
-				}
-			}  // for z
-		}  // for y
-	}  // if (XZ file open)
-	#endif  // 0
 }
 
 
@@ -247,7 +184,7 @@ cNoise3DGenerator::~cNoise3DGenerator()
 void cNoise3DGenerator::Initialize(cIniFile & a_IniFile)
 {
 	// Params:
-	m_SeaLevel            =                 a_IniFile.GetValueSetI("Generator", "Noise3DSeaLevel", 62);
+	m_SeaLevel            =                 a_IniFile.GetValueSetI("Generator", "SeaLevel", 62);
 	m_HeightAmplification = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "Noise3DHeightAmplification", 0.1);
 	m_MidPoint            = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "Noise3DMidPoint", 68);
 	m_FrequencyX          = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "Noise3DFrequencyX", 8);
@@ -455,7 +392,6 @@ void cNoise3DComposable::Initialize(cIniFile & a_IniFile)
 {
 	// Params:
 	// The defaults generate extreme hills terrain
-	m_SeaLevel            =                 a_IniFile.GetValueSetI("Generator", "Noise3DSeaLevel", 62);
 	m_HeightAmplification = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "Noise3DHeightAmplification", 0.045);
 	m_MidPoint            = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "Noise3DMidPoint", 75);
 	m_FrequencyX          = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "Noise3DFrequencyX", 40);
@@ -523,110 +459,60 @@ void cNoise3DComposable::GenerateNoiseArrayIfNeeded(int a_ChunkX, int a_ChunkZ)
 	NOISE_DATATYPE BaseNoise[5 * 5];
 	NOISE_DATATYPE BlockX = static_cast<NOISE_DATATYPE>(a_ChunkX * cChunkDef::Width);
 	NOISE_DATATYPE BlockZ = static_cast<NOISE_DATATYPE>(a_ChunkZ * cChunkDef::Width);
-	// Note that we have to swap the coords, because noise generator uses [x + SizeX * y + SizeX * SizeY * z] ordering and we want "BlockY" to be "z":
-	m_ChoiceNoise.Generate3D  (ChoiceNoise,   5, 5, 33, BlockX / m_ChoiceFrequencyX, (BlockX + 17) / m_ChoiceFrequencyX, BlockZ / m_ChoiceFrequencyZ, (BlockZ + 17) / m_ChoiceFrequencyZ, 0, 257 / m_ChoiceFrequencyY, Workspace);
-	m_DensityNoiseA.Generate3D(DensityNoiseA, 5, 5, 33, BlockX / m_FrequencyX,       (BlockX + 17) / m_FrequencyX,       BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ,       0, 257 / m_FrequencyY,       Workspace);
-	m_DensityNoiseB.Generate3D(DensityNoiseB, 5, 5, 33, BlockX / m_FrequencyX,       (BlockX + 17) / m_FrequencyX,       BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ,       0, 257 / m_FrequencyY,       Workspace);
+	// Note that we have to swap the X and Y coords, because noise generator uses [x + SizeX * y + SizeX * SizeY * z] ordering and we want "BlockY" to be "x":
+	m_ChoiceNoise.Generate3D  (ChoiceNoise,   33, 5, 5, 0, 257 / m_ChoiceFrequencyY, BlockX / m_ChoiceFrequencyX, (BlockX + 17) / m_ChoiceFrequencyX, BlockZ / m_ChoiceFrequencyZ, (BlockZ + 17) / m_ChoiceFrequencyZ, Workspace);
+	m_DensityNoiseA.Generate3D(DensityNoiseA, 33, 5, 5, 0, 257 / m_FrequencyY,       BlockX / m_FrequencyX,       (BlockX + 17) / m_FrequencyX,       BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ,       Workspace);
+	m_DensityNoiseB.Generate3D(DensityNoiseB, 33, 5, 5, 0, 257 / m_FrequencyY,       BlockX / m_FrequencyX,       (BlockX + 17) / m_FrequencyX,       BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ,       Workspace);
 	m_BaseNoise.Generate2D    (BaseNoise,     5, 5,     BlockX / m_BaseFrequencyX,   (BlockX + 17) / m_BaseFrequencyX,   BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ, Workspace);
 
 	// Calculate the final noise based on the partial noises:
-	for (int y = 0; y < 33; y++)
+	for (int z = 0; z < 5; z++)
 	{
-		NOISE_DATATYPE AddHeight = (static_cast<NOISE_DATATYPE>(y * 8) - m_MidPoint) * m_HeightAmplification;
-
-		// If "underground", make the terrain smoother by forcing the vertical linear gradient into steeper slope:
-		if (AddHeight < 0)
-		{
-			AddHeight *= 4;
-		}
-
-		for (int z = 0; z < 5; z++)
+		for (int x = 0; x < 5; x++)
 		{
-			for (int x = 0; x < 5; x++)
+			NOISE_DATATYPE curBaseNoise = BaseNoise[x + 5 * z];
+			for (int y = 0; y < 33; y++)
 			{
-				int idx = x + 5 * z + 5 * 5 * y;
-				Workspace[idx] = ClampedLerp(DensityNoiseA[idx], DensityNoiseB[idx], 8 * (ChoiceNoise[idx] + 0.5f)) + AddHeight + BaseNoise[x + 5 * z];
-			}
-		}
-	}
-	LinearUpscale3DArray<NOISE_DATATYPE>(Workspace, 5, 5, 33, m_NoiseArray, 4, 4, 8);
-}
+				NOISE_DATATYPE AddHeight = (static_cast<NOISE_DATATYPE>(y * 8) - m_MidPoint) * m_HeightAmplification;
 
+				// If "underground", make the terrain smoother by forcing the vertical linear gradient into steeper slope:
+				if (AddHeight < 0)
+				{
+					AddHeight *= 4;
+				}
 
-
-
-
-void cNoise3DComposable::GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap)
-{
-	GenerateNoiseArrayIfNeeded(a_ChunkX, a_ChunkZ);
-
-	for (int z = 0; z < cChunkDef::Width; z++)
-	{
-		for (int x = 0; x < cChunkDef::Width; x++)
-		{
-			cChunkDef::SetHeight(a_HeightMap, x, z, m_SeaLevel);
-			for (int y = cChunkDef::Height - 1; y > m_SeaLevel; y--)
-			{
-				if (m_NoiseArray[y * 17 * 17 + z * 17 + x] <= m_AirThreshold)
+				// If too high, cut off any terrain:
+				if (y > 28)
 				{
-					cChunkDef::SetHeight(a_HeightMap, x, z, y);
-					break;
+					AddHeight = AddHeight + static_cast<NOISE_DATATYPE>(y - 28) / 4;
 				}
-			}  // for y
-		}  // for x
-	}  // for z
+
+				// Decide between the two density noises:
+				int idx = 33 * x + 33 * 5 * z + y;
+				Workspace[idx] = ClampedLerp(DensityNoiseA[idx], DensityNoiseB[idx], 8 * (ChoiceNoise[idx] + 0.5f)) + AddHeight + curBaseNoise;
+			}
+		}
+	}
+	LinearUpscale3DArray<NOISE_DATATYPE>(Workspace, 33, 5, 5, m_NoiseArray, 8, 4, 4);
 }
 
 
 
 
 
-void cNoise3DComposable::ComposeTerrain(cChunkDesc & a_ChunkDesc)
+void cNoise3DComposable::GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape)
 {
-	GenerateNoiseArrayIfNeeded(a_ChunkDesc.GetChunkX(), a_ChunkDesc.GetChunkZ());
-
-	a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
+	GenerateNoiseArrayIfNeeded(a_ChunkX, a_ChunkZ);
 
-	// Make basic terrain composition:
+	// Translate the noise array into Shape:
 	for (int z = 0; z < cChunkDef::Width; z++)
 	{
 		for (int x = 0; x < cChunkDef::Width; x++)
 		{
-			int LastAir = a_ChunkDesc.GetHeight(x, z) + 1;
-			bool HasHadWater = false;
-			for (int y = LastAir; y < m_SeaLevel; y++)
+			for (int y = 0; y < cChunkDef::Height; y++)
 			{
-				a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_STATIONARY_WATER);
+				a_Shape[y + x * 256 + z * 256 * 16] = (m_NoiseArray[y + 257 * x + 257 * 17 * z] > m_AirThreshold) ? 0 : 1;
 			}
-			for (int y = LastAir - 1; y > 0; y--)
-			{
-				if (m_NoiseArray[x + 17 * z + 17 * 17 * y] > m_AirThreshold)
-				{
-					// "air" part
-					LastAir = y;
-					if (y < m_SeaLevel)
-					{
-						a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_STATIONARY_WATER);
-						HasHadWater = true;
-					}
-					continue;
-				}
-				// "ground" part:
-				if (LastAir - y > 4)
-				{
-					a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_STONE);
-					continue;
-				}
-				if (HasHadWater)
-				{
-					a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_SAND);
-				}
-				else
-				{
-					a_ChunkDesc.SetBlockType(x, y, z, (LastAir == y + 1) ? E_BLOCK_GRASS : E_BLOCK_DIRT);
-				}
-			}  // for y
-			a_ChunkDesc.SetBlockType(x, 0, z, E_BLOCK_BEDROCK);
 		}  // for x
 	}  // for z
 }
@@ -651,7 +537,7 @@ cBiomalNoise3DComposable::cBiomalNoise3DComposable(int a_Seed, cBiomeGenPtr a_Bi
 	{
 		for (int x = 0; x <= AVERAGING_SIZE * 2; x++)
 		{
-			m_Weight[z][x] = static_cast<NOISE_DATATYPE>((5 - std::abs(5 - x)) + (5 - std::abs(5 - z)));
+			m_Weight[z][x] = static_cast<NOISE_DATATYPE>((AVERAGING_SIZE - std::abs(AVERAGING_SIZE - x)) + (AVERAGING_SIZE - std::abs(AVERAGING_SIZE - z)));
 			m_WeightSum += m_Weight[z][x];
 		}
 	}
@@ -665,7 +551,7 @@ void cBiomalNoise3DComposable::Initialize(cIniFile & a_IniFile)
 {
 	// Params:
 	// The defaults generate extreme hills terrain
-	m_SeaLevel            =                 a_IniFile.GetValueSetI("Generator", "BiomalNoise3DSeaLevel", 62);
+	m_SeaLevel            =                 a_IniFile.GetValueSetI("Generator", "SeaLevel", 62);
 	m_FrequencyX          = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "BiomalNoise3DFrequencyX", 40);
 	m_FrequencyY          = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "BiomalNoise3DFrequencyY", 40);
 	m_FrequencyZ          = (NOISE_DATATYPE)a_IniFile.GetValueSetF("Generator", "BiomalNoise3DFrequencyZ", 40);
@@ -736,34 +622,42 @@ void cBiomalNoise3DComposable::GenerateNoiseArrayIfNeeded(int a_ChunkX, int a_Ch
 	NOISE_DATATYPE BaseNoise[5 * 5];
 	NOISE_DATATYPE BlockX = static_cast<NOISE_DATATYPE>(a_ChunkX * cChunkDef::Width);
 	NOISE_DATATYPE BlockZ = static_cast<NOISE_DATATYPE>(a_ChunkZ * cChunkDef::Width);
-	// Note that we have to swap the coords, because noise generator uses [x + SizeX * y + SizeX * SizeY * z] ordering and we want "BlockY" to be "z":
-	m_ChoiceNoise.Generate3D  (ChoiceNoise,   5, 5, 33, BlockX / m_ChoiceFrequencyX, (BlockX + 17) / m_ChoiceFrequencyX, BlockZ / m_ChoiceFrequencyZ, (BlockZ + 17) / m_ChoiceFrequencyZ, 0, 257 / m_ChoiceFrequencyY, Workspace);
-	m_DensityNoiseA.Generate3D(DensityNoiseA, 5, 5, 33, BlockX / m_FrequencyX,       (BlockX + 17) / m_FrequencyX,       BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ,       0, 257 / m_FrequencyY,       Workspace);
-	m_DensityNoiseB.Generate3D(DensityNoiseB, 5, 5, 33, BlockX / m_FrequencyX,       (BlockX + 17) / m_FrequencyX,       BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ,       0, 257 / m_FrequencyY,       Workspace);
+	// Note that we have to swap the X and Y coords, because noise generator uses [x + SizeX * y + SizeX * SizeY * z] ordering and we want "BlockY" to be "x":
+	m_ChoiceNoise.Generate3D  (ChoiceNoise,   33, 5, 5, 0, 257 / m_ChoiceFrequencyY, BlockX / m_ChoiceFrequencyX, (BlockX + 17) / m_ChoiceFrequencyX, BlockZ / m_ChoiceFrequencyZ, (BlockZ + 17) / m_ChoiceFrequencyZ, Workspace);
+	m_DensityNoiseA.Generate3D(DensityNoiseA, 33, 5, 5, 0, 257 / m_FrequencyY,       BlockX / m_FrequencyX,       (BlockX + 17) / m_FrequencyX,       BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ,       Workspace);
+	m_DensityNoiseB.Generate3D(DensityNoiseB, 33, 5, 5, 0, 257 / m_FrequencyY,       BlockX / m_FrequencyX,       (BlockX + 17) / m_FrequencyX,       BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ,       Workspace);
 	m_BaseNoise.Generate2D    (BaseNoise,     5, 5,     BlockX / m_BaseFrequencyX,   (BlockX + 17) / m_BaseFrequencyX,   BlockZ / m_FrequencyZ,       (BlockZ + 17) / m_FrequencyZ, Workspace);
 
 	// Calculate the final noise based on the partial noises:
-	for (int y = 0; y < 33; y++)
+	for (int z = 0; z < 5; z++)
 	{
-		NOISE_DATATYPE BlockHeight = static_cast<NOISE_DATATYPE>(y * 8);
-		for (int z = 0; z < 5; z++)
+		for (int x = 0; x < 5; x++)
 		{
-			for (int x = 0; x < 5; x++)
+			NOISE_DATATYPE curMidPoint = MidPoint[x + 5 * z];
+			NOISE_DATATYPE curHeightAmp = HeightAmp[x + 5 * z];
+			NOISE_DATATYPE curBaseNoise = BaseNoise[x + 5 * z];
+			for (int y = 0; y < 33; y++)
 			{
-				NOISE_DATATYPE AddHeight = (BlockHeight - MidPoint[x + 5 * z]) * HeightAmp[x + 5 * z];
+				NOISE_DATATYPE AddHeight = (static_cast<NOISE_DATATYPE>(y * 8) - curMidPoint) * curHeightAmp;
 
 				// If "underground", make the terrain smoother by forcing the vertical linear gradient into steeper slope:
 				if (AddHeight < 0)
 				{
 					AddHeight *= 4;
 				}
+				// If too high, cut off any terrain:
+				if (y > 28)
+				{
+					AddHeight = AddHeight + static_cast<NOISE_DATATYPE>(y - 28) / 4;
+				}
 
-				int idx = x + 5 * z + 5 * 5 * y;
-				Workspace[idx] = ClampedLerp(DensityNoiseA[idx], DensityNoiseB[idx], 8 * (ChoiceNoise[idx] + 0.5f)) + AddHeight + BaseNoise[x + 5 * z];
+				// Decide between the two density noises:
+				int idx = 33 * x + y + 33 * 5 * z;
+				Workspace[idx] = ClampedLerp(DensityNoiseA[idx], DensityNoiseB[idx], 8 * (ChoiceNoise[idx] + 0.5f)) + AddHeight + curBaseNoise;
 			}
 		}
 	}
-	LinearUpscale3DArray<NOISE_DATATYPE>(Workspace, 5, 5, 33, m_NoiseArray, 4, 4, 8);
+	LinearUpscale3DArray<NOISE_DATATYPE>(Workspace, 33, 5, 5, m_NoiseArray, 8, 4, 4);
 }
 
 
@@ -821,72 +715,67 @@ void cBiomalNoise3DComposable::GetBiomeParams(EMCSBiome a_Biome, NOISE_DATATYPE
 {
 	switch (a_Biome)
 	{
-		case biBeach:                a_HeightAmp = 0.3f;   a_MidPoint = 62; break;
-		case biBirchForest:          a_HeightAmp = 0.1f;   a_MidPoint = 64; break;
-		case biBirchForestHills:     a_HeightAmp = 0.075f; a_MidPoint = 68; break;
-		case biBirchForestHillsM:    a_HeightAmp = 0.075f; a_MidPoint = 68; break;
-		case biBirchForestM:         a_HeightAmp = 0.1f;   a_MidPoint = 64; break;
-		case biColdBeach:            a_HeightAmp = 0.3f;   a_MidPoint = 62; break;
-		case biDesertHills:          a_HeightAmp = 0.075f; a_MidPoint = 68; break;
-		case biDeepOcean:            a_HeightAmp = 0.17f;  a_MidPoint = 35; break;
-		case biDesert:               a_HeightAmp = 0.29f;  a_MidPoint = 62; break;
-		case biEnd:                  a_HeightAmp = 0.15f;  a_MidPoint = 64; break;
-		case biExtremeHills:         a_HeightAmp = 0.045f; a_MidPoint = 75; break;
-		case biExtremeHillsPlus:     a_HeightAmp = 0.04f;  a_MidPoint = 80; break;
-		case biFlowerForest:         a_HeightAmp = 0.1f;   a_MidPoint = 64; break;
-		case biForest:               a_HeightAmp = 0.1f;   a_MidPoint = 64; break;
-		case biForestHills:          a_HeightAmp = 0.075f; a_MidPoint = 68; break;
-		case biFrozenRiver:          a_HeightAmp = 0.4f;   a_MidPoint = 53; break;
-		case biFrozenOcean:          a_HeightAmp = 0.17f;  a_MidPoint = 47; break;
-		case biIceMountains:         a_HeightAmp = 0.075f; a_MidPoint = 68; break;
-		case biIcePlains:            a_HeightAmp = 0.3f;   a_MidPoint = 62; break;
-		case biIcePlainsSpikes:      a_HeightAmp = 0.3f;   a_MidPoint = 62; break;
-		case biJungle:               a_HeightAmp = 0.1f;   a_MidPoint = 63; break;
-		case biJungleHills:          a_HeightAmp = 0.075f; a_MidPoint = 68; break;
-		case biJungleM:              a_HeightAmp = 0.1f;   a_MidPoint = 63; break;
-		case biMegaSpruceTaigaHills: a_HeightAmp = 0.075f; a_MidPoint = 68; break;
-		case biMegaTaigaHills:       a_HeightAmp = 0.075f; a_MidPoint = 68; break;
-		case biMushroomShore:        a_HeightAmp = 0.15f;  a_MidPoint = 15; break;
-		case biOcean:                a_HeightAmp = 0.3f;   a_MidPoint = 62; break;
-		case biPlains:               a_HeightAmp = 0.3f;   a_MidPoint = 62; break;
-		case biRiver:                a_HeightAmp = 0.4f;   a_MidPoint = 53; break;
-		case biSwampland:            a_HeightAmp = 0.25f;  a_MidPoint = 59; break;
-		case biSwamplandM:           a_HeightAmp = 0.11f;  a_MidPoint = 59; break;
-		case biTaigaHills:           a_HeightAmp = 0.075f; a_MidPoint = 68; break;
-
-		/*
-		// Still missing:
-		case biColdTaiga:            a_HeightAmp = 0.15f;  a_MidPoint = 30; break;
-		case biColdTaigaHills:       a_HeightAmp = 0.15f;  a_MidPoint = 31; break;
-		case biColdTaigaM:           a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biDesertM:              a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biExtremeHillsEdge:     a_HeightAmp = 0.15f;  a_MidPoint = 20; break;
-		case biExtremeHillsM:        a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biExtremeHillsPlusM:    a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biJungleEdge:           a_HeightAmp = 0.15f;  a_MidPoint = 23; break;
-		case biJungleEdgeM:          a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biMegaSpruceTaiga:      a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biMegaTaiga:            a_HeightAmp = 0.15f;  a_MidPoint = 32; break;
-		case biMesa:                 a_HeightAmp = 0.15f;  a_MidPoint = 37; break;
-		case biMesaBryce:            a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biMesaPlateau:          a_HeightAmp = 0.15f;  a_MidPoint = 39; break;
-		case biMesaPlateauF:         a_HeightAmp = 0.15f;  a_MidPoint = 38; break;
-		case biMesaPlateauFM:        a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biMesaPlateauM:         a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biMushroomIsland:       a_HeightAmp = 0.15f;  a_MidPoint = 14; break;
-		case biNether:               a_HeightAmp = 0.15f;  a_MidPoint = 68; break;
-		case biRoofedForest:         a_HeightAmp = 0.15f;  a_MidPoint = 29; break;
-		case biRoofedForestM:        a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biSavanna:              a_HeightAmp = 0.15f;  a_MidPoint = 35; break;
-		case biSavannaM:             a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biSavannaPlateau:       a_HeightAmp = 0.15f;  a_MidPoint = 36; break;
-		case biSavannaPlateauM:      a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biStoneBeach:           a_HeightAmp = 0.15f;  a_MidPoint = 25; break;
-		case biSunflowerPlains:      a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		case biTaiga:                a_HeightAmp = 0.15f;  a_MidPoint = 65; break;
-		case biTaigaM:               a_HeightAmp = 0.15f;  a_MidPoint = 70; break;
-		*/
-
+		case biBeach:                a_HeightAmp = 0.2f;   a_MidPoint =  60; break;
+		case biBirchForest:          a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biBirchForestHills:     a_HeightAmp = 0.075f; a_MidPoint =  68; break;
+		case biBirchForestHillsM:    a_HeightAmp = 0.075f; a_MidPoint =  68; break;
+		case biBirchForestM:         a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biColdBeach:            a_HeightAmp = 0.3f;   a_MidPoint =  62; break;
+		case biColdTaiga:            a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biColdTaigaM:           a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biColdTaigaHills:       a_HeightAmp = 0.075f; a_MidPoint =  68; break;
+		case biDesertHills:          a_HeightAmp = 0.075f; a_MidPoint =  68; break;
+		case biDeepOcean:            a_HeightAmp = 0.17f;  a_MidPoint =  35; break;
+		case biDesert:               a_HeightAmp = 0.29f;  a_MidPoint =  62; break;
+		case biDesertM:              a_HeightAmp = 0.29f;  a_MidPoint =  62; break;
+		case biEnd:                  a_HeightAmp = 0.15f;  a_MidPoint =  64; break;
+		case biExtremeHills:         a_HeightAmp = 0.045f; a_MidPoint =  75; break;
+		case biExtremeHillsEdge:     a_HeightAmp = 0.1f;   a_MidPoint =  70; break;
+		case biExtremeHillsM:        a_HeightAmp = 0.045f; a_MidPoint =  75; break;
+		case biExtremeHillsPlus:     a_HeightAmp = 0.04f;  a_MidPoint =  80; break;
+		case biExtremeHillsPlusM:    a_HeightAmp = 0.04f;  a_MidPoint =  80; break;
+		case biFlowerForest:         a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biForest:               a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biForestHills:          a_HeightAmp = 0.075f; a_MidPoint =  68; break;
+		case biFrozenRiver:          a_HeightAmp = 0.4f;   a_MidPoint =  57; break;
+		case biFrozenOcean:          a_HeightAmp = 0.12f;  a_MidPoint =  45; break;
+		case biIceMountains:         a_HeightAmp = 0.075f; a_MidPoint =  68; break;
+		case biIcePlains:            a_HeightAmp = 0.3f;   a_MidPoint =  62; break;
+		case biIcePlainsSpikes:      a_HeightAmp = 0.3f;   a_MidPoint =  62; break;
+		case biJungle:               a_HeightAmp = 0.1f;   a_MidPoint =  63; break;
+		case biJungleEdge:           a_HeightAmp = 0.15f;  a_MidPoint =  62; break;
+		case biJungleEdgeM:          a_HeightAmp = 0.15f;  a_MidPoint =  62; break;
+		case biJungleHills:          a_HeightAmp = 0.075f; a_MidPoint =  68; break;
+		case biJungleM:              a_HeightAmp = 0.1f;   a_MidPoint =  63; break;
+		case biMegaSpruceTaiga:      a_HeightAmp = 0.09f;  a_MidPoint =  64; break;
+		case biMegaSpruceTaigaHills: a_HeightAmp = 0.075f; a_MidPoint =  68; break;
+		case biMegaTaiga:            a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biMegaTaigaHills:       a_HeightAmp = 0.075f; a_MidPoint =  68; break;
+		case biMesa:                 a_HeightAmp = 0.09f;  a_MidPoint =  61; break;
+		case biMesaBryce:            a_HeightAmp = 0.15f;  a_MidPoint =  61; break;
+		case biMesaPlateau:          a_HeightAmp = 0.25f;  a_MidPoint =  86; break;
+		case biMesaPlateauF:         a_HeightAmp = 0.25f;  a_MidPoint =  96; break;
+		case biMesaPlateauFM:        a_HeightAmp = 0.25f;  a_MidPoint =  96; break;
+		case biMesaPlateauM:         a_HeightAmp = 0.25f;  a_MidPoint =  86; break;
+		case biMushroomShore:        a_HeightAmp = 0.075f; a_MidPoint =  60; break;
+		case biMushroomIsland:       a_HeightAmp = 0.06f;  a_MidPoint =  80; break;
+		case biNether:               a_HeightAmp = 0.01f;  a_MidPoint =  64; break;
+		case biOcean:                a_HeightAmp = 0.12f;  a_MidPoint =  45; break;
+		case biPlains:               a_HeightAmp = 0.3f;   a_MidPoint =  62; break;
+		case biRiver:                a_HeightAmp = 0.4f;   a_MidPoint =  57; break;
+		case biRoofedForest:         a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biRoofedForestM:        a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biSavanna:              a_HeightAmp = 0.3f;   a_MidPoint =  62; break;
+		case biSavannaM:             a_HeightAmp = 0.3f;   a_MidPoint =  62; break;
+		case biSavannaPlateau:       a_HeightAmp = 0.3f;   a_MidPoint =  85; break;
+		case biSavannaPlateauM:      a_HeightAmp = 0.012f; a_MidPoint = 105; break;
+		case biStoneBeach:           a_HeightAmp = 0.075f; a_MidPoint =  60; break;
+		case biSunflowerPlains:      a_HeightAmp = 0.3f;   a_MidPoint =  62; break;
+		case biSwampland:            a_HeightAmp = 0.25f;  a_MidPoint =  59; break;
+		case biSwamplandM:           a_HeightAmp = 0.11f;  a_MidPoint =  59; break;
+		case biTaiga:                a_HeightAmp = 0.1f;   a_MidPoint =  64; break;
+		case biTaigaM:               a_HeightAmp = 0.1f;   a_MidPoint =  70; break;
+		case biTaigaHills:           a_HeightAmp = 0.075f; a_MidPoint =  68; break;
 		default:
 		{
 			// Make a crazy terrain so that it stands out
@@ -900,78 +789,19 @@ void cBiomalNoise3DComposable::GetBiomeParams(EMCSBiome a_Biome, NOISE_DATATYPE
 
 
 
-
-void cBiomalNoise3DComposable::GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap)
+void cBiomalNoise3DComposable::GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape)
 {
 	GenerateNoiseArrayIfNeeded(a_ChunkX, a_ChunkZ);
 
+	// Translate the noise array into Shape:
 	for (int z = 0; z < cChunkDef::Width; z++)
 	{
 		for (int x = 0; x < cChunkDef::Width; x++)
 		{
-			cChunkDef::SetHeight(a_HeightMap, x, z, m_SeaLevel);
-			for (int y = cChunkDef::Height - 1; y > m_SeaLevel; y--)
-			{
-				if (m_NoiseArray[y * 17 * 17 + z * 17 + x] <= m_AirThreshold)
-				{
-					cChunkDef::SetHeight(a_HeightMap, x, z, y);
-					break;
-				}
-			}  // for y
-		}  // for x
-	}  // for z
-}
-
-
-
-
-
-void cBiomalNoise3DComposable::ComposeTerrain(cChunkDesc & a_ChunkDesc)
-{
-	GenerateNoiseArrayIfNeeded(a_ChunkDesc.GetChunkX(), a_ChunkDesc.GetChunkZ());
-
-	a_ChunkDesc.FillBlocks(E_BLOCK_AIR, 0);
-
-	// Make basic terrain composition:
-	for (int z = 0; z < cChunkDef::Width; z++)
-	{
-		for (int x = 0; x < cChunkDef::Width; x++)
-		{
-			int LastAir = a_ChunkDesc.GetHeight(x, z) + 1;
-			bool HasHadWater = false;
-			for (int y = LastAir; y < m_SeaLevel; y++)
+			for (int y = 0; y < cChunkDef::Height; y++)
 			{
-				a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_STATIONARY_WATER);
+				a_Shape[y + x * 256 + z * 256 * 16] = (m_NoiseArray[y + 257 * x + 257 * 17 * z] > m_AirThreshold) ? 0 : 1;
 			}
-			for (int y = LastAir - 1; y > 0; y--)
-			{
-				if (m_NoiseArray[x + 17 * z + 17 * 17 * y] > m_AirThreshold)
-				{
-					// "air" part
-					LastAir = y;
-					if (y < m_SeaLevel)
-					{
-						a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_STATIONARY_WATER);
-						HasHadWater = true;
-					}
-					continue;
-				}
-				// "ground" part:
-				if (LastAir - y > 4)
-				{
-					a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_STONE);
-					continue;
-				}
-				if (HasHadWater)
-				{
-					a_ChunkDesc.SetBlockType(x, y, z, E_BLOCK_SAND);
-				}
-				else
-				{
-					a_ChunkDesc.SetBlockType(x, y, z, (LastAir == y + 1) ? E_BLOCK_GRASS : E_BLOCK_DIRT);
-				}
-			}  // for y
-			a_ChunkDesc.SetBlockType(x, 0, z, E_BLOCK_BEDROCK);
 		}  // for x
 	}  // for z
 }
@@ -979,3 +809,4 @@ void cBiomalNoise3DComposable::ComposeTerrain(cChunkDesc & a_ChunkDesc)
 
 
 
+
diff --git a/src/Generating/Noise3DGenerator.h b/src/Generating/Noise3DGenerator.h
index 07767ba84..35b1e4c94 100644
--- a/src/Generating/Noise3DGenerator.h
+++ b/src/Generating/Noise3DGenerator.h
@@ -73,8 +73,7 @@ protected:
 
 
 class cNoise3DComposable :
-	public cTerrainHeightGen,
-	public cTerrainCompositionGen
+	public cTerrainShapeGen
 {
 public:
 	cNoise3DComposable(int a_Seed);
@@ -82,21 +81,18 @@ public:
 	void Initialize(cIniFile & a_IniFile);
 
 protected:
-	/** The noise that is used to choose between density noise A and B. */
-	cPerlinNoise m_ChoiceNoise;
+	/** The 3D noise that is used to choose between density noise A and B. */
+	cOctavedNoise<cInterpolNoise<Interp5Deg>> m_ChoiceNoise;
 
 	/** Density 3D noise, variant A. */
-	cPerlinNoise m_DensityNoiseA;
+	cOctavedNoise<cInterpolNoise<Interp5Deg>> m_DensityNoiseA;
 
 	/** Density 3D noise, variant B. */
-	cPerlinNoise m_DensityNoiseB;
+	cOctavedNoise<cInterpolNoise<Interp5Deg>> m_DensityNoiseB;
 
 	/** Heightmap-like noise used to provide variance for low-amplitude biomes. */
-	cPerlinNoise m_BaseNoise;
+	cOctavedNoise<cInterpolNoise<Interp5Deg>> m_BaseNoise;
 	
-	/** Block height of the sealevel, used for composing the terrain. */
-	int m_SeaLevel;
-
 	/** The main parameter of the generator, specifies the slope of the vertical linear gradient.
 	A higher value means a steeper slope and a smaller total amplitude of the generated terrain. */
 	NOISE_DATATYPE m_HeightAmplification;
@@ -131,12 +127,8 @@ protected:
 	void GenerateNoiseArrayIfNeeded(int a_ChunkX, int a_ChunkZ);
 	
 	// cTerrainHeightGen overrides:
-	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
-	virtual void InitializeHeightGen(cIniFile & a_IniFile) override { Initialize(a_IniFile); }
-
-	// cTerrainCompositionGen overrides:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
-	virtual void InitializeCompoGen(cIniFile & a_IniFile) override { Initialize(a_IniFile); }
+	virtual void GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape) override;
+	virtual void InitializeShapeGen(cIniFile & a_IniFile) override { Initialize(a_IniFile); }
 } ;
 
 
@@ -144,8 +136,7 @@ protected:
 
 
 class cBiomalNoise3DComposable :
-	public cTerrainHeightGen,
-	public cTerrainCompositionGen
+	public cTerrainShapeGen
 {
 public:
 	cBiomalNoise3DComposable(int a_Seed, cBiomeGenPtr a_BiomeGen);
@@ -153,24 +144,24 @@ public:
 	void Initialize(cIniFile & a_IniFile);
 
 protected:
-	/** Number of columns around the pixel to query for biomes for averaging. */
-	static const int AVERAGING_SIZE = 5;
+	/** Number of columns around the pixel to query for biomes for averaging. Must be less than or equal to 16. */
+	static const int AVERAGING_SIZE = 9;
 
 	/** Type used for a single parameter across the entire (downscaled) chunk. */
 	typedef NOISE_DATATYPE ChunkParam[5 * 5];
 
 
 	/** The noise that is used to choose between density noise A and B. */
-	cPerlinNoise m_ChoiceNoise;
+	cOctavedNoise<cInterpolNoise<Interp5Deg>> m_ChoiceNoise;
 
 	/** Density 3D noise, variant A. */
-	cPerlinNoise m_DensityNoiseA;
+	cOctavedNoise<cInterpolNoise<Interp5Deg>> m_DensityNoiseA;
 
 	/** Density 3D noise, variant B. */
-	cPerlinNoise m_DensityNoiseB;
+	cOctavedNoise<cInterpolNoise<Interp5Deg>> m_DensityNoiseB;
 
 	/** Heightmap-like noise used to provide variance for low-amplitude biomes. */
-	cPerlinNoise m_BaseNoise;
+	cOctavedNoise<cInterpolNoise<Interp5Deg>> m_BaseNoise;
 
 	/** The underlying biome generator. */
 	cBiomeGenPtr m_BiomeGen;
@@ -198,7 +189,7 @@ protected:
 	// Cache for the last calculated chunk (reused between heightmap and composition queries):
 	int m_LastChunkX;
 	int m_LastChunkZ;
-	NOISE_DATATYPE m_NoiseArray[17 * 17 * 257];  // x + 17 * z + 17 * 17 * y
+	NOISE_DATATYPE m_NoiseArray[17 * 17 * 257];  // 257 * x + y + 257 * 17 * z
 
 	/** Weights for summing up neighboring biomes. */
 	NOISE_DATATYPE m_Weight[AVERAGING_SIZE * 2 + 1][AVERAGING_SIZE * 2 + 1];
@@ -216,13 +207,9 @@ protected:
 	/** Returns the parameters for the specified biome. */
 	void GetBiomeParams(EMCSBiome a_Biome, NOISE_DATATYPE & a_HeightAmp, NOISE_DATATYPE & a_MidPoint);
 	
-	// cTerrainHeightGen overrides:
-	virtual void GenHeightMap(int a_ChunkX, int a_ChunkZ, cChunkDef::HeightMap & a_HeightMap) override;
-	virtual void InitializeHeightGen(cIniFile & a_IniFile) override { Initialize(a_IniFile); }
-
-	// cTerrainCompositionGen overrides:
-	virtual void ComposeTerrain(cChunkDesc & a_ChunkDesc) override;
-	virtual void InitializeCompoGen(cIniFile & a_IniFile) override { Initialize(a_IniFile); }
+	// cTerrainShapeGen overrides:
+	virtual void GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape) override;
+	virtual void InitializeShapeGen(cIniFile & a_IniFile) override { Initialize(a_IniFile); }
 } ;
 
 
diff --git a/src/Generating/ShapeGen.cpp b/src/Generating/ShapeGen.cpp
new file mode 100644
index 000000000..45a9c3b93
--- /dev/null
+++ b/src/Generating/ShapeGen.cpp
@@ -0,0 +1,145 @@
+
+// ShapeGen.cpp
+
+// Implements the function to create a cTerrainShapeGen descendant based on INI file settings
+
+#include "Globals.h"
+#include "HeiGen.h"
+#include "../IniFile.h"
+#include "DistortedHeightmap.h"
+#include "EndGen.h"
+#include "Noise3DGenerator.h"
+#include "TwoHeights.h"
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// cTerrainHeightToShapeGen:
+
+/** Converts old-style height-generators into new-style shape-generators. */
+class cTerrainHeightToShapeGen:
+	public cTerrainShapeGen
+{
+public:
+	cTerrainHeightToShapeGen(cTerrainHeightGenPtr a_HeightGen):
+		m_HeightGen(a_HeightGen)
+	{
+	}
+
+
+	// cTerrainShapeGen overrides:
+	virtual void GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape) override
+	{
+		// Generate the heightmap:
+		cChunkDef::HeightMap heightMap;
+		m_HeightGen->GenHeightMap(a_ChunkX, a_ChunkZ, heightMap);
+
+		// Convert from heightmap to shape:
+		for (int z = 0; z < cChunkDef::Width; z++)
+		{
+			for (int x = 0; x < cChunkDef::Width; x++)
+			{
+				HEIGHTTYPE height = cChunkDef::GetHeight(heightMap, x, z) + 1;
+				Byte * shapeColumn = &(a_Shape[(x + 16 * z) * 256]);
+				for (int y = 0; y < height; y++)
+				{
+					shapeColumn[y] = 1;
+				}
+				for (int y = height; y < cChunkDef::Height; y++)
+				{
+					shapeColumn[y] = 0;
+				}
+			}  // for x
+		}  // for z
+	}
+
+
+	virtual void InitializeShapeGen(cIniFile & a_IniFile) override
+	{
+		m_HeightGen->InitializeHeightGen(a_IniFile);
+	}
+
+protected:
+	/** The height generator being converted. */
+	cTerrainHeightGenPtr m_HeightGen;
+};
+
+typedef SharedPtr<cTerrainHeightToShapeGen> cTerrainHeightToShapeGenPtr;
+
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// cTerrainShapeGen:
+
+cTerrainShapeGenPtr cTerrainShapeGen::CreateShapeGen(cIniFile & a_IniFile, cBiomeGenPtr a_BiomeGen, int a_Seed, bool & a_CacheOffByDefault)
+{
+	AString shapeGenName = a_IniFile.GetValueSet("Generator", "ShapeGen", "");
+	if (shapeGenName.empty())
+	{
+		LOGWARN("[Generator] ShapeGen value not set in world.ini, using \"BiomalNoise3D\".");
+		shapeGenName = "BiomalNoise3D";
+	}
+	
+	// If the shapegen is HeightMap, redirect to older HeightMap-based generators:
+	if (NoCaseCompare(shapeGenName, "HeightMap") == 0)
+	{
+		cTerrainHeightGenPtr heightGen = cTerrainHeightGen::CreateHeightGen(a_IniFile, a_BiomeGen, a_Seed, a_CacheOffByDefault);
+		if (heightGen != nullptr)
+		{
+			return std::make_shared<cTerrainHeightToShapeGen>(heightGen);
+		}
+
+		// The height gen was not recognized; several heightgens were promoted to shape gens, so let's try them instead:
+		shapeGenName = a_IniFile.GetValue("Generator", "HeightGen", "");
+		if (shapeGenName.empty())
+		{
+			LOGWARNING("[Generator] ShapeGen set to HeightMap, but HeightGen not set. Reverting to \"BiomalNoise3D\".");
+			shapeGenName = "BiomalNoise3D";
+			a_IniFile.SetValue("Generator", "ShapeGen", shapeGenName);
+		}
+	}
+
+	// Choose the shape generator based on the name:
+	a_CacheOffByDefault = false;
+	cTerrainShapeGenPtr res;
+	if (NoCaseCompare(shapeGenName, "DistortedHeightmap") == 0)
+	{
+		res = std::make_shared<cDistortedHeightmap>(a_Seed, a_BiomeGen);
+	}
+	else if (NoCaseCompare(shapeGenName, "End") == 0)
+	{
+		res = std::make_shared<cEndGen>(a_Seed);
+	}
+	else if (NoCaseCompare(shapeGenName, "BiomalNoise3D") == 0)
+	{
+		res = std::make_shared<cBiomalNoise3DComposable>(a_Seed, a_BiomeGen);
+	}
+	else if (NoCaseCompare(shapeGenName, "Noise3D") == 0)
+	{
+		res = std::make_shared<cNoise3DComposable>(a_Seed);
+	}
+	else if (NoCaseCompare(shapeGenName, "TwoHeights") == 0)
+	{
+		res = CreateShapeGenTwoHeights(a_Seed, a_BiomeGen);
+	}
+	else
+	{
+		// No match found, force-set the default and retry
+		LOGWARN("Unknown ShapeGen \"%s\", using \"BiomalNoise3D\" instead.", shapeGenName.c_str());
+		a_IniFile.SetValue("Generator", "ShapeGen", "BiomalNoise3D");
+		return CreateShapeGen(a_IniFile, a_BiomeGen, a_Seed, a_CacheOffByDefault);
+	}
+	
+	// Read the settings:
+	res->InitializeShapeGen(a_IniFile);
+	
+	return res;
+}
+
+
+
+
diff --git a/src/Generating/StructGen.cpp b/src/Generating/StructGen.cpp
index bdefcd8c1..2f685c808 100644
--- a/src/Generating/StructGen.cpp
+++ b/src/Generating/StructGen.cpp
@@ -37,10 +37,13 @@ void cStructGenTrees::GenFinish(cChunkDesc & a_ChunkDesc)
 				Dest = &WorkerDesc;
 				WorkerDesc.SetChunkCoords(BaseX, BaseZ);
 				
+				// TODO: This may cause a lot of wasted calculations, instead of pulling data out of a single (cChunkDesc) cache
+
+				cChunkDesc::Shape workerShape;
 				m_BiomeGen->GenBiomes           (BaseX, BaseZ, WorkerDesc.GetBiomeMap());
-				m_HeightGen->GenHeightMap       (BaseX, BaseZ, WorkerDesc.GetHeightMap());
-				m_CompositionGen->ComposeTerrain(WorkerDesc);
-				// TODO: Free the entity lists
+				m_ShapeGen->GenShape            (BaseX, BaseZ, workerShape);
+				WorkerDesc.SetHeightFromShape   (workerShape);
+				m_CompositionGen->ComposeTerrain(WorkerDesc, workerShape);
 			}
 			else
 			{
@@ -97,7 +100,7 @@ void cStructGenTrees::GenerateSingleTree(
 	
 	int Height = a_ChunkDesc.GetHeight(x, z);
 	
-	if ((Height <= 0) || (Height > 240))
+	if ((Height <= 0) || (Height >= 230))
 	{
 		return;
 	}
@@ -125,6 +128,11 @@ void cStructGenTrees::GenerateSingleTree(
 			// Outside the chunk
 			continue;
 		}
+		if (itr->y >= cChunkDef::Height)
+		{
+			// Above the chunk, cut off (this shouldn't happen too often, we're limiting trees to y < 230)
+			continue;
+		}
 
 		BLOCKTYPE Block = a_ChunkDesc.GetBlockType(itr->x, itr->y, itr->z);
 		switch (Block)
@@ -159,7 +167,7 @@ void cStructGenTrees::ApplyTreeImage(
 	// Put the generated image into a_BlockTypes, push things outside this chunk into a_Blocks
 	for (sSetBlockVector::const_iterator itr = a_Image.begin(), end = a_Image.end(); itr != end; ++itr)
 	{
-		if ((itr->ChunkX == a_ChunkX) && (itr->ChunkZ == a_ChunkZ))
+		if ((itr->ChunkX == a_ChunkX) && (itr->ChunkZ == a_ChunkZ) && (itr->y < cChunkDef::Height))
 		{
 			// Inside this chunk, integrate into a_ChunkDesc:
 			switch (a_ChunkDesc.GetBlockType(itr->x, itr->y, itr->z))
@@ -390,7 +398,7 @@ void cStructGenLakes::GenFinish(cChunkDesc & a_ChunkDesc)
 		}
 		
 		cBlockArea Lake;
-		CreateLakeImage(ChunkX + x, ChunkZ + z, Lake);
+		CreateLakeImage(ChunkX + x, ChunkZ + z, a_ChunkDesc.GetMinHeight(), Lake);
 		
 		int OfsX = Lake.GetOriginX() + x * cChunkDef::Width;
 		int OfsZ = Lake.GetOriginZ() + z * cChunkDef::Width;
@@ -404,25 +412,13 @@ void cStructGenLakes::GenFinish(cChunkDesc & a_ChunkDesc)
 
 
 
-void cStructGenLakes::CreateLakeImage(int a_ChunkX, int a_ChunkZ, cBlockArea & a_Lake)
+void cStructGenLakes::CreateLakeImage(int a_ChunkX, int a_ChunkZ, int a_MaxLakeHeight, cBlockArea & a_Lake)
 {
 	a_Lake.Create(16, 8, 16);
 	a_Lake.Fill(cBlockArea::baTypes, E_BLOCK_SPONGE);  // Sponge is the NOP blocktype for lake merging strategy
 	
-	// Find the minimum height in this chunk:
-	cChunkDef::HeightMap HeightMap;
-	m_HeiGen->GenHeightMap(a_ChunkX, a_ChunkZ, HeightMap);
-	HEIGHTTYPE MinHeight = HeightMap[0];
-	for (size_t i = 1; i < ARRAYCOUNT(HeightMap); i++)
-	{
-		if (HeightMap[i] < MinHeight)
-		{
-			MinHeight = HeightMap[i];
-		}
-	}
-	
 	// Make a random position in the chunk by using a random 16 block XZ offset and random height up to chunk's max height minus 6
-	MinHeight = std::max(MinHeight - 6, 2);
+	int MinHeight = std::max(a_MaxLakeHeight - 6, 2);
 	int Rnd = m_Noise.IntNoise3DInt(a_ChunkX, 128, a_ChunkZ) / 11;
 	// Random offset [-8 .. 8], with higher probability around 0; add up four three-bit-wide randoms [0 .. 28], divide and subtract to get range
 	int OffsetX = 4 * ((Rnd & 0x07) + ((Rnd & 0x38) >> 3) + ((Rnd & 0x1c0) >> 6) + ((Rnd & 0xe00) >> 9)) / 7 - 8;
diff --git a/src/Generating/StructGen.h b/src/Generating/StructGen.h
index d3b0b5544..796abf0f5 100644
--- a/src/Generating/StructGen.h
+++ b/src/Generating/StructGen.h
@@ -24,11 +24,11 @@ class cStructGenTrees :
 	public cFinishGen
 {
 public:
-	cStructGenTrees(int a_Seed, cBiomeGenPtr a_BiomeGen, cTerrainHeightGenPtr a_HeightGen, cTerrainCompositionGenPtr a_CompositionGen) :
+	cStructGenTrees(int a_Seed, cBiomeGenPtr a_BiomeGen, cTerrainShapeGenPtr a_ShapeGen, cTerrainCompositionGenPtr a_CompositionGen) :
 		m_Seed(a_Seed),
 		m_Noise(a_Seed),
 		m_BiomeGen(a_BiomeGen),
-		m_HeightGen(a_HeightGen),
+		m_ShapeGen(a_ShapeGen),
 		m_CompositionGen(a_CompositionGen)
 	{}
 	
@@ -37,12 +37,12 @@ protected:
 	int m_Seed;
 	cNoise m_Noise;
 	cBiomeGenPtr              m_BiomeGen;
-	cTerrainHeightGenPtr      m_HeightGen;
+	cTerrainShapeGenPtr       m_ShapeGen;
 	cTerrainCompositionGenPtr m_CompositionGen;
 	
 	/** Generates and applies an image of a single tree.
-	Parts of the tree inside the chunk are applied to a_BlockX.
-	Parts of the tree outside the chunk are stored in a_OutsideX
+	Parts of the tree inside the chunk are applied to a_ChunkDesc.
+	Parts of the tree outside the chunk are stored in a_OutsideXYZ
 	*/
 	void GenerateSingleTree(
 		int a_ChunkX, int a_ChunkZ, int a_Seq,
@@ -51,7 +51,7 @@ protected:
 		sSetBlockVector & a_OutsideOther
 	) ;
 	
-	/// Applies an image into chunk blockdata; all blocks outside the chunk will be appended to a_Overflow
+	/** Applies an image into chunk blockdata; all blocks outside the chunk will be appended to a_Overflow. */
 	void ApplyTreeImage(
 		int a_ChunkX, int a_ChunkZ,
 		cChunkDesc & a_ChunkDesc,
@@ -124,27 +124,30 @@ class cStructGenLakes :
 	public cFinishGen
 {
 public:
-	cStructGenLakes(int a_Seed, BLOCKTYPE a_Fluid, cTerrainHeightGenPtr a_HeiGen, int a_Probability) :
+	cStructGenLakes(int a_Seed, BLOCKTYPE a_Fluid, cTerrainShapeGenPtr a_ShapeGen, int a_Probability) :
 		m_Noise(a_Seed),
 		m_Seed(a_Seed),
 		m_Fluid(a_Fluid),
-		m_HeiGen(a_HeiGen),
+		m_ShapeGen(a_ShapeGen),
 		m_Probability(a_Probability)
 	{
 	}
 	
 protected:
-	cNoise               m_Noise;
-	int                  m_Seed;
-	BLOCKTYPE            m_Fluid;
-	cTerrainHeightGenPtr m_HeiGen;
-	int                  m_Probability;  ///< Chance, 0 .. 100, of a chunk having the lake
+	cNoise              m_Noise;
+	int                 m_Seed;
+	BLOCKTYPE           m_Fluid;
+	cTerrainShapeGenPtr m_ShapeGen;
+
+	/** Chance, [0 .. 100], of a chunk having the lake. */
+	int m_Probability;
 	
+
 	// cFinishGen override:
 	virtual void GenFinish(cChunkDesc & a_ChunkDesc) override;
 	
-	/// Creates a lake image for the specified chunk into a_Lake
-	void CreateLakeImage(int a_ChunkX, int a_ChunkZ, cBlockArea & a_Lake);
+	/** Creates a lake image for the specified chunk into a_Lake. */
+	void CreateLakeImage(int a_ChunkX, int a_ChunkZ, int a_MaxLakeHeight, cBlockArea & a_Lake);
 } ;
 
 
diff --git a/src/Generating/TwoHeights.cpp b/src/Generating/TwoHeights.cpp
new file mode 100644
index 000000000..e75c301de
--- /dev/null
+++ b/src/Generating/TwoHeights.cpp
@@ -0,0 +1,121 @@
+
+// TwoHeights.cpp
+
+// Implements the cTwoHeights class representing the terrain shape generator using two switched heightmaps
+
+#include "Globals.h"
+#include "TwoHeights.h"
+#include "../Noise/InterpolNoise.h"
+#include "HeiGen.h"
+#include "../LinearUpscale.h"
+#include "../IniFile.h"
+
+
+
+
+
+class cTwoHeights:
+	public cTerrainShapeGen
+{
+	typedef cTerrainShapeGen super;
+public:
+	cTwoHeights(int a_Seed, cBiomeGenPtr a_BiomeGen):
+		m_Seed(a_Seed),
+		m_Choice(a_Seed),
+		m_HeightA(a_Seed + 1, a_BiomeGen),
+		m_HeightB(a_Seed + 2, a_BiomeGen)
+	{
+	}
+
+
+	// cTerrainShapeGen override:
+	virtual void GenShape(int a_ChunkX, int a_ChunkZ, cChunkDesc::Shape & a_Shape) override
+	{
+		// Generate the two heightmaps:
+		cChunkDef::HeightMap heightsA;
+		cChunkDef::HeightMap heightsB;
+		m_HeightA.GenHeightMap(a_ChunkX, a_ChunkZ, heightsA);
+		m_HeightB.GenHeightMap(a_ChunkX, a_ChunkZ, heightsB);
+
+		// Generate the choice noise:
+		NOISE_DATATYPE smallChoice[33 * 5 * 5];
+		NOISE_DATATYPE workspace[33 * 5 * 5];
+		NOISE_DATATYPE startX = 0;
+		NOISE_DATATYPE endX = 256 * m_FrequencyY;
+		NOISE_DATATYPE startY =  a_ChunkX * cChunkDef::Width * m_FrequencyX;
+		NOISE_DATATYPE endY   = (a_ChunkX * cChunkDef::Width + cChunkDef::Width + 1) * m_FrequencyX;
+		NOISE_DATATYPE startZ =  a_ChunkZ * cChunkDef::Width * m_FrequencyZ;
+		NOISE_DATATYPE endZ   = (a_ChunkZ * cChunkDef::Width + cChunkDef::Width + 1) * m_FrequencyZ;
+		m_Choice.Generate3D(smallChoice, 33, 5, 5, startX, endX, startY, endY, startZ, endZ, workspace);
+		NOISE_DATATYPE choice[257 * 17 * 17];
+		LinearUpscale3DArray(smallChoice, 33, 5, 5, choice, 8, 4, 4);
+
+		// Generate the shape:
+		int idxShape = 0;
+		for (int z = 0; z < cChunkDef::Width; z++)
+		{
+			for (int x = 0; x < cChunkDef::Width; x++)
+			{
+				int idxChoice = 257 * 17 * z + 257 * x;
+				NOISE_DATATYPE heightA = static_cast<NOISE_DATATYPE>(cChunkDef::GetHeight(heightsA, x, z));
+				NOISE_DATATYPE heightB = static_cast<NOISE_DATATYPE>(cChunkDef::GetHeight(heightsB, x, z));
+				for (int y = 0; y < cChunkDef::Height; y++)
+				{
+					int height = static_cast<int>(ClampedLerp(heightA, heightB, choice[idxChoice++]));
+					a_Shape[idxShape++] = (y < height) ? 1 : 0;
+				}
+			}  // for x
+		}  // for z
+	}
+
+
+	virtual void InitializeShapeGen(cIniFile & a_IniFile)
+	{
+		m_FrequencyX = static_cast<NOISE_DATATYPE>(a_IniFile.GetValueSetF("Generator", "TwoHeightsFrequencyX", 40));
+		m_FrequencyY = static_cast<NOISE_DATATYPE>(a_IniFile.GetValueSetF("Generator", "TwoHeightsFrequencyY", 40));
+		m_FrequencyZ = static_cast<NOISE_DATATYPE>(a_IniFile.GetValueSetF("Generator", "TwoHeightsFrequencyZ", 40));
+
+		// Initialize the two underlying height generators from an empty INI file:
+		cIniFile empty;
+		m_HeightA.InitializeHeightGen(empty);
+		m_HeightB.InitializeHeightGen(empty);
+
+		// Add the choice octaves:
+		NOISE_DATATYPE freq = 0.001f;
+		NOISE_DATATYPE ampl = 1;
+		for (int i = 0; i < 4; i++)
+		{
+			m_Choice.AddOctave(freq, ampl);
+			freq = freq * 2;
+			ampl = ampl / 2;
+		}
+	}
+
+protected:
+	int m_Seed;
+
+	/** The noise used to decide between the two heightmaps. */
+	cOctavedNoise<cInterpolNoise<Interp5Deg>> m_Choice;
+
+	/** The first height generator. */
+	cHeiGenBiomal m_HeightA;
+
+	/** The second height generator. */
+	cHeiGenBiomal m_HeightB;
+
+	/** The base frequencies for m_Choice in each of the world axis directions. */
+	NOISE_DATATYPE m_FrequencyX, m_FrequencyY, m_FrequencyZ;
+};
+
+
+
+
+
+cTerrainShapeGenPtr CreateShapeGenTwoHeights(int a_Seed, cBiomeGenPtr a_BiomeGen)
+{
+	return std::make_shared<cTwoHeights>(a_Seed, a_BiomeGen);
+}
+
+
+
+
diff --git a/src/Generating/TwoHeights.h b/src/Generating/TwoHeights.h
new file mode 100644
index 000000000..353598011
--- /dev/null
+++ b/src/Generating/TwoHeights.h
@@ -0,0 +1,23 @@
+
+// TwoHeights.h
+
+// Declares the function to create a new instance of the cTwoHeights terrain shape generator
+
+
+
+
+
+#pragma once
+
+#include "ComposableGenerator.h"
+
+
+
+
+/** Creates and returns a new instance of the cTwoHeights terrain shape generator.
+The instance must be Initialize()-d before it is used. */
+extern cTerrainShapeGenPtr CreateShapeGenTwoHeights(int a_Seed, cBiomeGenPtr a_BiomeGen);
+
+
+
+
diff --git a/src/Generating/VillageGen.cpp b/src/Generating/VillageGen.cpp
index a9b359b6a..f7d9a8316 100644
--- a/src/Generating/VillageGen.cpp
+++ b/src/Generating/VillageGen.cpp
@@ -18,8 +18,8 @@
 
 /*
 How village generating works:
-By descending from a cGridStructGen, a semi-random grid is generated. A village may be generated for each of
-the grid's cells. Each cell checks the biomes in an entire chunk around it, only generating a village if all
+By descending from a cGridStructGen, a semi-random (jitter) grid is generated. A village may be generated for each
+of the grid's cells. Each cell checks the biomes in an entire chunk around it, only generating a village if all
 biomes are village-friendly. If yes, the entire village structure is built for that cell. If not, the cell
 is left village-less.
 
@@ -125,7 +125,7 @@ public:
 		m_Noise(a_Seed),
 		m_MaxSize(a_MaxSize),
 		m_Density(a_Density),
-		m_Borders(a_OriginX - a_MaxSize, 0, a_OriginZ - a_MaxSize, a_OriginX + a_MaxSize, 255, a_OriginZ + a_MaxSize),
+		m_Borders(a_OriginX - a_MaxSize, 0, a_OriginZ - a_MaxSize, a_OriginX + a_MaxSize, cChunkDef::Height - 1, a_OriginZ + a_MaxSize),
 		m_Prefabs(a_Prefabs),
 		m_HeightGen(a_HeightGen),
 		m_RoadBlock(a_RoadBlock),
diff --git a/src/Mobs/Monster.cpp b/src/Mobs/Monster.cpp
index 23b4d9f45..5319bdf91 100644
--- a/src/Mobs/Monster.cpp
+++ b/src/Mobs/Monster.cpp
@@ -160,7 +160,7 @@ void cMonster::TickPathFinding()
 		BLOCKTYPE BlockAtYP = m_World->GetBlock(gCrossCoords[i].x + PosX, PosY + 1, gCrossCoords[i].z + PosZ);
 		BLOCKTYPE BlockAtYPP = m_World->GetBlock(gCrossCoords[i].x + PosX, PosY + 2, gCrossCoords[i].z + PosZ);
 		int LowestY = FindFirstNonAirBlockPosition(gCrossCoords[i].x + PosX, gCrossCoords[i].z + PosZ);
-		BLOCKTYPE BlockAtLowestY = m_World->GetBlock(gCrossCoords[i].x + PosX, LowestY, gCrossCoords[i].z + PosZ);
+		BLOCKTYPE BlockAtLowestY = (LowestY >= cChunkDef::Height) ? E_BLOCK_AIR : m_World->GetBlock(gCrossCoords[i].x + PosX, LowestY, gCrossCoords[i].z + PosZ);
 
 		if (
 			(!cBlockInfo::IsSolid(BlockAtY)) &&
@@ -453,7 +453,7 @@ int cMonster::FindFirstNonAirBlockPosition(double a_PosX, double a_PosZ)
 	}
 	else
 	{
-		while (cBlockInfo::IsSolid(m_World->GetBlock((int)floor(a_PosX), PosY, (int)floor(a_PosZ))) && (PosY < cChunkDef::Height))
+		while ((PosY < cChunkDef::Height) && cBlockInfo::IsSolid(m_World->GetBlock((int)floor(a_PosX), PosY, (int)floor(a_PosZ))))
 		{
 			PosY++;
 		}
diff --git a/src/Mobs/Monster.h b/src/Mobs/Monster.h
index f5ae2cb4d..e5dcb0309 100644
--- a/src/Mobs/Monster.h
+++ b/src/Mobs/Monster.h
@@ -169,10 +169,12 @@ protected:
 	/** Stores if mobile is currently moving towards the ultimate, final destination */
 	bool m_bMovingToDestination;
 
-	/** Finds the first non-air block position (not the highest, as cWorld::GetHeight does)
-		If current Y is nonsolid, goes down to try to find a solid block, then returns that + 1
-		If current Y is solid, goes up to find first nonsolid block, and returns that */
+	/** Finds the lowest non-air block position (not the highest, as cWorld::GetHeight does)
+	If current Y is nonsolid, goes down to try to find a solid block, then returns that + 1
+	If current Y is solid, goes up to find first nonsolid block, and returns that.
+	If no suitable position is found, returns cChunkDef::Height. */
 	int FindFirstNonAirBlockPosition(double a_PosX, double a_PosZ);
+
 	/** Returns if a monster can actually reach a given height by jumping or walking */
 	inline bool IsNextYPosReachable(int a_PosY)
 	{
diff --git a/src/World.cpp b/src/World.cpp
index 001ea72c7..0dec0bd96 100644
--- a/src/World.cpp
+++ b/src/World.cpp
@@ -732,28 +732,32 @@ void cWorld::InitialiseGeneratorDefaults(cIniFile & a_IniFile)
 	{
 		case dimEnd:
 		{
-			a_IniFile.GetValueSet("Generator", "BiomeGen", "Constant");
-			a_IniFile.GetValueSet("Generator", "ConstantBiome", "End");
-			a_IniFile.GetValueSet("Generator", "HeightGen", "Biomal");
+			a_IniFile.GetValueSet("Generator", "Generator",      "Composable");
+			a_IniFile.GetValueSet("Generator", "BiomeGen",       "Constant");
+			a_IniFile.GetValueSet("Generator", "ConstantBiome",  "End");
+			a_IniFile.GetValueSet("Generator", "ShapeGen",       "End");
 			a_IniFile.GetValueSet("Generator", "CompositionGen", "End");
 			break;
 		}
 		case dimOverworld:
 		{
-			a_IniFile.GetValueSet("Generator", "BiomeGen", "MultiStepMap");
-			a_IniFile.GetValueSet("Generator", "HeightGen", "DistortedHeightmap");
-			a_IniFile.GetValueSet("Generator", "CompositionGen", "DistortedHeightmap");
-			a_IniFile.GetValueSet("Generator", "Finishers", "Ravines, WormNestCaves, WaterLakes, WaterSprings, LavaLakes, LavaSprings, OreNests, Mineshafts, Trees, SprinkleFoliage, Ice, Snow, Lilypads, BottomLava, DeadBushes, PreSimulator");
+			a_IniFile.GetValueSet("Generator", "Generator",      "Composable");
+			a_IniFile.GetValueSet("Generator", "BiomeGen",       "Grown");
+			a_IniFile.GetValueSet("Generator", "ShapeGen",       "BiomalNoise3D");
+			a_IniFile.GetValueSet("Generator", "CompositionGen", "Biomal");
+			a_IniFile.GetValueSet("Generator", "Finishers",      "Ravines, WormNestCaves, WaterLakes, WaterSprings, LavaLakes, LavaSprings, OreNests, Mineshafts, Trees, Villages, SprinkleFoliage, Ice, Snow, Lilypads, BottomLava, DeadBushes, PreSimulator");
 			break;
 		}
 		case dimNether:
 		{
-			a_IniFile.GetValueSet("Generator", "BiomeGen", "Constant");
-			a_IniFile.GetValueSet("Generator", "ConstantBiome", "Nether");
-			a_IniFile.GetValueSet("Generator", "HeightGen", "Flat");
-			a_IniFile.GetValueSet("Generator", "FlatHeight", "128");
-			a_IniFile.GetValueSet("Generator", "CompositionGen", "Nether");
-			a_IniFile.GetValueSet("Generator", "Finishers", "WormNestCaves, BottomLava, LavaSprings, NetherClumpFoliage, NetherForts, PreSimulator");
+			a_IniFile.GetValueSet("Generator", "Generator",        "Composable");
+			a_IniFile.GetValueSet("Generator", "BiomeGen",         "Constant");
+			a_IniFile.GetValueSet("Generator", "ConstantBiome",    "Nether");
+			a_IniFile.GetValueSet("Generator", "ShapeGen",         "HeightMap");
+			a_IniFile.GetValueSet("Generator", "HeightGen",        "Flat");
+			a_IniFile.GetValueSet("Generator", "FlatHeight",       "128");
+			a_IniFile.GetValueSet("Generator", "CompositionGen",   "Nether");
+			a_IniFile.GetValueSet("Generator", "Finishers",        "WormNestCaves, BottomLava, LavaSprings, NetherClumpFoliage, NetherForts, PreSimulator");
 			a_IniFile.GetValueSet("Generator", "BottomLavaHeight", "30");
 			break;
 		}