1 files changed, 712 insertions, 0 deletions

diff --git a/src/Generating/StructGen.cpp b/src/Generating/StructGen.cpp
new file mode 100644
index 000000000..504c26238
--- /dev/null
+++ b/src/Generating/StructGen.cpp
@@ -0,0 +1,712 @@
+
+// StructGen.h
+
+#include "Globals.h"
+#include "StructGen.h"
+#include "../BlockID.h"
+#include "Trees.h"
+#include "../BlockArea.h"
+#include "../LinearUpscale.h"
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cStructGenOreNests configuration:
+
+const int MAX_HEIGHT_COAL = 127;
+const int NUM_NESTS_COAL = 50;
+const int NEST_SIZE_COAL = 10;
+
+const int MAX_HEIGHT_IRON = 64;
+const int NUM_NESTS_IRON = 14;
+const int NEST_SIZE_IRON = 6;
+
+const int MAX_HEIGHT_REDSTONE = 16;
+const int NUM_NESTS_REDSTONE = 4;
+const int NEST_SIZE_REDSTONE = 6;
+
+const int MAX_HEIGHT_GOLD = 32;
+const int NUM_NESTS_GOLD = 2;
+const int NEST_SIZE_GOLD = 6;
+
+const int MAX_HEIGHT_DIAMOND = 15;
+const int NUM_NESTS_DIAMOND = 1;
+const int NEST_SIZE_DIAMOND = 4;
+
+const int MAX_HEIGHT_LAPIS = 30;
+const int NUM_NESTS_LAPIS = 2;
+const int NEST_SIZE_LAPIS = 5;
+
+const int MAX_HEIGHT_DIRT = 127;
+const int NUM_NESTS_DIRT = 20;
+const int NEST_SIZE_DIRT = 32;
+
+const int MAX_HEIGHT_GRAVEL = 70;
+const int NUM_NESTS_GRAVEL = 15;
+const int NEST_SIZE_GRAVEL = 32;
+
+
+
+
+
+template <typename T> T Clamp(T a_Value, T a_Min, T a_Max)
+{
+	return (a_Value < a_Min) ? a_Min : ((a_Value > a_Max) ? a_Max : a_Value);
+}
+
+
+
+
+
+static bool SortTreeBlocks(const sSetBlock & a_First, const sSetBlock & a_Second)
+{
+	return (a_First.BlockType == E_BLOCK_LOG) && (a_Second.BlockType != E_BLOCK_LOG);
+}
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cStructGenTrees:
+
+void cStructGenTrees::GenStructures(cChunkDesc & a_ChunkDesc)
+{
+	int ChunkX = a_ChunkDesc.GetChunkX();
+	int ChunkZ = a_ChunkDesc.GetChunkZ();
+	
+	cChunkDesc WorkerDesc(ChunkX, ChunkZ);
+	
+	// Generate trees:
+	for (int x = 0; x <= 2; x++)
+	{
+		int BaseX = ChunkX + x - 1;
+		for (int z = 0; z <= 2; z++)
+		{
+			int BaseZ = ChunkZ + z - 1;
+			
+			cChunkDesc * Dest;
+
+			if ((x != 1) || (z != 1))
+			{
+				Dest = &WorkerDesc;
+				WorkerDesc.SetChunkCoords(BaseX, BaseZ);
+				
+				m_BiomeGen->GenBiomes           (BaseX, BaseZ, WorkerDesc.GetBiomeMap());
+				m_HeightGen->GenHeightMap       (BaseX, BaseZ, WorkerDesc.GetHeightMap());
+				m_CompositionGen->ComposeTerrain(WorkerDesc);
+				// TODO: Free the entity lists
+			}
+			else
+			{
+				Dest = &a_ChunkDesc;
+			}
+
+			int NumTrees = GetNumTrees(BaseX, BaseZ, Dest->GetBiomeMap());
+
+			sSetBlockVector OutsideLogs, OutsideOther;
+			for (int i = 0; i < NumTrees; i++)
+			{
+				GenerateSingleTree(BaseX, BaseZ, i, *Dest, OutsideLogs, OutsideOther);
+			}
+
+			sSetBlockVector IgnoredOverflow;
+			IgnoredOverflow.reserve(OutsideOther.size());
+			ApplyTreeImage(ChunkX, ChunkZ, a_ChunkDesc, OutsideOther, IgnoredOverflow);
+			IgnoredOverflow.clear();
+			IgnoredOverflow.reserve(OutsideLogs.size());
+			ApplyTreeImage(ChunkX, ChunkZ, a_ChunkDesc, OutsideLogs, IgnoredOverflow);
+		}  // for z
+	}  // for x
+	
+	// Update the heightmap:
+	for (int x = 0; x < cChunkDef::Width; x++)
+	{
+		for (int z = 0; z < cChunkDef::Width; z++)
+		{
+			for (int y = cChunkDef::Height - 1; y >= 0; y--)
+			{
+				if (a_ChunkDesc.GetBlockType(x, y, z) != E_BLOCK_AIR)
+				{
+					a_ChunkDesc.SetHeight(x, z, y);
+					break;
+				}
+			}  // for y
+		}  // for z
+	}  // for x
+}
+
+
+
+
+
+void cStructGenTrees::GenerateSingleTree(
+	int a_ChunkX, int a_ChunkZ, int a_Seq,
+	cChunkDesc & a_ChunkDesc,
+	sSetBlockVector & a_OutsideLogs,
+	sSetBlockVector & a_OutsideOther
+)
+{
+	int x = (m_Noise.IntNoise3DInt(a_ChunkX + a_ChunkZ, a_ChunkZ, a_Seq) / 19) % cChunkDef::Width;
+	int z = (m_Noise.IntNoise3DInt(a_ChunkX - a_ChunkZ, a_Seq, a_ChunkZ) / 19) % cChunkDef::Width;
+	
+	int Height = a_ChunkDesc.GetHeight(x, z);
+	
+	if ((Height <= 0) || (Height > 240))
+	{
+		return;
+	}
+
+	// Check the block underneath the tree:
+	BLOCKTYPE TopBlock = a_ChunkDesc.GetBlockType(x, Height, z);
+	if ((TopBlock != E_BLOCK_DIRT) && (TopBlock != E_BLOCK_GRASS) && (TopBlock != E_BLOCK_FARMLAND))
+	{
+		return;
+	}
+	
+	sSetBlockVector TreeLogs, TreeOther;
+	GetTreeImageByBiome(
+		a_ChunkX * cChunkDef::Width + x, Height + 1, a_ChunkZ * cChunkDef::Width + z,
+		m_Noise, a_Seq, 
+		a_ChunkDesc.GetBiome(x, z),
+		TreeLogs, TreeOther
+	);
+
+	// Check if the generated image fits the terrain. Only the logs are checked:
+	for (sSetBlockVector::const_iterator itr = TreeLogs.begin(); itr != TreeLogs.end(); ++itr)
+	{
+		if ((itr->ChunkX != a_ChunkX) || (itr->ChunkZ != a_ChunkZ))
+		{
+			// Outside the chunk
+			continue;
+		}
+
+		BLOCKTYPE Block = a_ChunkDesc.GetBlockType(itr->x, itr->y, itr->z);
+		switch (Block)
+		{
+			CASE_TREE_ALLOWED_BLOCKS:
+			{
+				break;
+			}
+			default:
+			{
+				// There's something in the way, abort this tree altogether
+				return;
+			}
+		}
+	}
+	
+	ApplyTreeImage(a_ChunkX, a_ChunkZ, a_ChunkDesc, TreeOther, a_OutsideOther);
+	ApplyTreeImage(a_ChunkX, a_ChunkZ, a_ChunkDesc, TreeLogs,  a_OutsideLogs);	
+}
+
+
+
+
+
+void cStructGenTrees::ApplyTreeImage(
+	int a_ChunkX, int a_ChunkZ,
+	cChunkDesc & a_ChunkDesc,
+	const sSetBlockVector & a_Image,
+	sSetBlockVector & a_Overflow
+)
+{
+	// 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))
+		{
+			// Inside this chunk, integrate into a_ChunkDesc:
+			switch (a_ChunkDesc.GetBlockType(itr->x, itr->y, itr->z))
+			{
+				case E_BLOCK_LEAVES:
+				{
+					if (itr->BlockType != E_BLOCK_LOG)
+					{
+						break;
+					}
+					// fallthrough:
+				}
+				CASE_TREE_OVERWRITTEN_BLOCKS:
+				{
+					a_ChunkDesc.SetBlockTypeMeta(itr->x, itr->y, itr->z, itr->BlockType, itr->BlockMeta);
+					break;
+				}
+				
+			}  // switch (GetBlock())
+			continue;
+		}
+		
+		// Outside the chunk, push into a_Overflow.
+		// Don't check if already present there, by separating logs and others we don't need the checks anymore:
+		a_Overflow.push_back(*itr);
+	}
+}
+
+
+
+
+
+int cStructGenTrees::GetNumTrees(
+	int a_ChunkX, int a_ChunkZ,
+	const cChunkDef::BiomeMap & a_Biomes
+)
+{
+	int NumTrees = 0;
+	for (int x = 0; x < cChunkDef::Width; x++) for (int z = 0; z < cChunkDef::Width; z++)
+	{
+		int Add = 0;
+		switch (cChunkDef::GetBiome(a_Biomes, x, z))
+		{
+			case biOcean:                Add =   2; break;
+			case biDesert:               Add =   0; break;
+			case biPlains:               Add =   1; break;
+			case biExtremeHills:         Add =   3; break;
+			case biForest:               Add =  30; break;
+			case biTaiga:                Add =  30; break;
+			case biSwampland:            Add =   8; break;
+			case biIcePlains:            Add =   1; break;
+			case biIceMountains:         Add =   1; break;
+			case biMushroomIsland:       Add =   3; break;
+			case biMushroomShore:        Add =   3; break;
+			case biForestHills:          Add =  20; break;
+			case biTaigaHills:           Add =  20; break;
+			case biExtremeHillsEdge:     Add =   5; break;
+			case biJungle:               Add = 120; break;
+			case biJungleHills:          Add =  90; break;
+			case biJungleEdge:           Add =  90; break;
+			case biBirchForest:          Add =  30; break;
+			case biBirchForestHills:     Add =  20; break;
+			case biRoofedForest:         Add =  50; break;
+			case biColdTaiga:            Add =  20; break;
+			case biColdTaigaHills:       Add =  15; break;
+			case biMegaTaiga:            Add =  30; break;
+			case biMegaTaigaHills:       Add =  25; break;
+			case biExtremeHillsPlus:     Add =   3; break;
+			case biSavanna:              Add =   8; break;
+			case biSavannaPlateau:       Add =  12; break;
+			case biMesa:                 Add =   2; break;
+			case biMesaPlateauF:         Add =   8; break;
+			case biMesaPlateau:          Add =   8; break;
+			case biSunflowerPlains:      Add =   1; break;
+			case biDesertM:              Add =   0; break;
+			case biExtremeHillsM:        Add =   4; break;
+			case biFlowerForest:         Add =  30; break;
+			case biTaigaM:               Add =  30; break;
+			case biSwamplandM:           Add =   8; break;
+			case biIcePlainsSpikes:      Add =   1; break;
+			case biJungleM:              Add = 120; break;
+			case biJungleEdgeM:          Add =  90; break;
+			case biBirchForestM:         Add =  30; break;
+			case biBirchForestHillsM:    Add =  20; break;
+			case biRoofedForestM:        Add =  40; break;
+			case biColdTaigaM:           Add =  30; break;
+			case biMegaSpruceTaiga:      Add =  30; break;
+			case biMegaSpruceTaigaHills: Add =  30; break;
+			case biExtremeHillsPlusM:    Add =   4; break;
+			case biSavannaM:             Add =   8; break;
+			case biSavannaPlateauM:      Add =  12; break;
+			case biMesaBryce:            Add =   4; break;
+			case biMesaPlateauFM:        Add =  12; break;
+			case biMesaPlateauM:         Add =  12; break;
+		}
+		NumTrees += Add;
+	}
+	return NumTrees / 1024;
+}
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cStructGenOreNests:
+
+void cStructGenOreNests::GenStructures(cChunkDesc & a_ChunkDesc)
+{
+	int ChunkX = a_ChunkDesc.GetChunkX();
+	int ChunkZ = a_ChunkDesc.GetChunkZ();
+	cChunkDef::BlockTypes & BlockTypes = a_ChunkDesc.GetBlockTypes();
+	GenerateOre(ChunkX, ChunkZ, E_BLOCK_COAL_ORE,     MAX_HEIGHT_COAL,     NUM_NESTS_COAL,     NEST_SIZE_COAL,     BlockTypes, 1);
+	GenerateOre(ChunkX, ChunkZ, E_BLOCK_IRON_ORE,     MAX_HEIGHT_IRON,     NUM_NESTS_IRON,     NEST_SIZE_IRON,     BlockTypes, 2);
+	GenerateOre(ChunkX, ChunkZ, E_BLOCK_REDSTONE_ORE, MAX_HEIGHT_REDSTONE, NUM_NESTS_REDSTONE, NEST_SIZE_REDSTONE, BlockTypes, 3);
+	GenerateOre(ChunkX, ChunkZ, E_BLOCK_GOLD_ORE,     MAX_HEIGHT_GOLD,     NUM_NESTS_GOLD,     NEST_SIZE_GOLD,     BlockTypes, 4);
+	GenerateOre(ChunkX, ChunkZ, E_BLOCK_DIAMOND_ORE,  MAX_HEIGHT_DIAMOND,  NUM_NESTS_DIAMOND,  NEST_SIZE_DIAMOND,  BlockTypes, 5);
+	GenerateOre(ChunkX, ChunkZ, E_BLOCK_LAPIS_ORE,    MAX_HEIGHT_LAPIS,    NUM_NESTS_LAPIS,    NEST_SIZE_LAPIS,    BlockTypes, 6);
+	GenerateOre(ChunkX, ChunkZ, E_BLOCK_DIRT,         MAX_HEIGHT_DIRT,     NUM_NESTS_DIRT,     NEST_SIZE_DIRT,     BlockTypes, 10);
+	GenerateOre(ChunkX, ChunkZ, E_BLOCK_GRAVEL,       MAX_HEIGHT_GRAVEL,   NUM_NESTS_GRAVEL,   NEST_SIZE_GRAVEL,   BlockTypes, 11);
+}
+
+
+
+
+
+void cStructGenOreNests::GenerateOre(int a_ChunkX, int a_ChunkZ, BLOCKTYPE a_OreType, int a_MaxHeight, int a_NumNests, int a_NestSize, cChunkDef::BlockTypes & a_BlockTypes, int a_Seq)
+{
+	// This function generates several "nests" of ore, each nest consisting of number of ore blocks relatively adjacent to each other.
+	// It does so by making a random XYZ walk and adding ore along the way in cuboids of different (random) sizes
+	// Only stone gets replaced with ore, all other blocks stay (so the nest can actually be smaller than specified).
+	
+	for (int i = 0; i < a_NumNests; i++)
+	{
+		int rnd = m_Noise.IntNoise3DInt(a_ChunkX + i, a_Seq, a_ChunkZ + 64 * i) / 8;
+		int BaseX = rnd % cChunkDef::Width;
+		rnd /= cChunkDef::Width;
+		int BaseZ = rnd % cChunkDef::Width;
+		rnd /= cChunkDef::Width;
+		int BaseY = rnd % a_MaxHeight;
+		rnd /= a_MaxHeight;
+		int NestSize = a_NestSize + (rnd % (a_NestSize / 4));  // The actual nest size may be up to 1/4 larger
+		int Num = 0;
+		while (Num < NestSize)
+		{
+			// Put a cuboid around [BaseX, BaseY, BaseZ]
+			int rnd = m_Noise.IntNoise3DInt(a_ChunkX + 64 * i, 2 * a_Seq + Num, a_ChunkZ + 32 * i) / 8;
+			int xsize = rnd % 2;
+			int ysize = (rnd / 4) % 2;
+			int zsize = (rnd / 16) % 2;
+			rnd >>= 8;
+			for (int x = xsize; x >= 0; --x)
+			{
+				int BlockX = BaseX + x;
+				if ((BlockX < 0) || (BlockX >= cChunkDef::Width))
+				{
+					Num++;  // So that the cycle finishes even if the base coords wander away from the chunk
+					continue;
+				}
+				for (int y = ysize; y >= 0; --y)
+				{
+					int BlockY = BaseY + y;
+					if ((BlockY < 0) || (BlockY >= cChunkDef::Height))
+					{
+						Num++;  // So that the cycle finishes even if the base coords wander away from the chunk
+						continue;
+					}
+					for (int z = zsize; z >= 0; --z)
+					{
+						int BlockZ = BaseZ + z;
+						if ((BlockZ < 0) || (BlockZ >= cChunkDef::Width))
+						{
+							Num++;  // So that the cycle finishes even if the base coords wander away from the chunk
+							continue;
+						}
+
+						int Index = cChunkDef::MakeIndexNoCheck(BlockX, BlockY, BlockZ);
+						if (a_BlockTypes[Index] == E_BLOCK_STONE)
+						{
+							a_BlockTypes[Index] = a_OreType;
+						}
+						Num++;
+					}  // for z
+				}  // for y
+			}  // for x
+			
+			// Move the base to a neighbor voxel
+			switch (rnd % 4)
+			{
+				case 0: BaseX--; break;
+				case 1: BaseX++; break;
+			}
+			switch ((rnd >> 3) % 4)
+			{
+				case 0: BaseY--; break;
+				case 1: BaseY++; break;
+			}
+			switch ((rnd >> 6) % 4)
+			{
+				case 0: BaseZ--; break;
+				case 1: BaseZ++; break;
+			}
+		}  // while (Num < NumBlocks)
+	}  // for i - NumNests
+}
+
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cStructGenLakes:
+
+void cStructGenLakes::GenStructures(cChunkDesc & a_ChunkDesc)
+{
+	int ChunkX = a_ChunkDesc.GetChunkX();
+	int ChunkZ = a_ChunkDesc.GetChunkZ();
+	
+	for (int z = -1; z < 2; z++) for (int x = -1; x < 2; x++)
+	{
+		if (((m_Noise.IntNoise2DInt(ChunkX + x, ChunkZ + z) / 17) % 100) > m_Probability)
+		{
+			continue;
+		}
+		
+		cBlockArea Lake;
+		CreateLakeImage(ChunkX + x, ChunkZ + z, Lake);
+		
+		int OfsX = Lake.GetOriginX() + x * cChunkDef::Width;
+		int OfsZ = Lake.GetOriginZ() + z * cChunkDef::Width;
+		
+		// Merge the lake into the current data
+		a_ChunkDesc.WriteBlockArea(Lake, OfsX, Lake.GetOriginY(), OfsZ, cBlockArea::msLake);
+	}  // for x, z - neighbor chunks
+}
+
+
+
+
+
+void cStructGenLakes::CreateLakeImage(int a_ChunkX, int a_ChunkZ, 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 (int 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 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;
+	Rnd >>= 12;
+	// 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 OffsetZ = 4 * ((Rnd & 0x07) + ((Rnd & 0x38) >> 3) + ((Rnd & 0x1c0) >> 6) + ((Rnd & 0xe00) >> 9)) / 7 - 8;
+	Rnd = m_Noise.IntNoise3DInt(a_ChunkX, 512, a_ChunkZ) / 13;
+	// Random height [1 .. MinHeight] with preference to center heights
+	int HeightY = 1 + (((Rnd & 0x1ff) % MinHeight) + (((Rnd >> 9) & 0x1ff) % MinHeight)) / 2;
+	
+	a_Lake.SetOrigin(OffsetX, HeightY, OffsetZ);
+	
+	// Hollow out a few bubbles inside the blockarea:
+	int NumBubbles = 4 + ((Rnd >> 18) & 0x03);  // 4 .. 7 bubbles
+	BLOCKTYPE * BlockTypes = a_Lake.GetBlockTypes();
+	for (int i = 0; i < NumBubbles; i++)
+	{
+		int Rnd = m_Noise.IntNoise3DInt(a_ChunkX, i, a_ChunkZ) / 13;
+		const int BubbleR = 2 + (Rnd & 0x03);  // 2 .. 5
+		const int Range = 16 - 2 * BubbleR;
+		const int BubbleX = BubbleR + (Rnd % Range);
+		Rnd >>= 4;
+		const int BubbleY = 4 + (Rnd & 0x01);  // 4 .. 5
+		Rnd >>= 1;
+		const int BubbleZ = BubbleR + (Rnd % Range);
+		Rnd >>= 4;
+		const int HalfR = BubbleR / 2;  // 1 .. 2
+		const int RSquared = BubbleR * BubbleR;
+		for (int y = -HalfR; y <= HalfR; y++)
+		{
+			// BubbleY + y is in the [0, 7] bounds
+			int DistY = 4 * y * y / 3;
+			int IdxY = (BubbleY + y) * 16 * 16;
+			for (int z = -BubbleR; z <= BubbleR; z++)
+			{
+				int DistYZ = DistY + z * z;
+				if (DistYZ >= RSquared)
+				{
+					continue;
+				}
+				int IdxYZ = BubbleX + IdxY + (BubbleZ + z) * 16;
+				for (int x = -BubbleR; x <= BubbleR; x++) 
+				{
+					if (x * x + DistYZ < RSquared)
+					{
+						BlockTypes[x + IdxYZ] = E_BLOCK_AIR;
+					}
+				}  // for x
+			}  // for z
+		}  // for y
+	}  // for i - bubbles
+
+	// Turn air in the bottom half into liquid:	
+	for (int y = 0; y < 4; y++)
+	{
+		for (int z = 0; z < 16; z++) for (int x = 0; x < 16; x++) 
+		{
+			if (BlockTypes[x + z * 16 + y * 16 * 16] == E_BLOCK_AIR)
+			{
+				BlockTypes[x + z * 16 + y * 16 * 16] = m_Fluid;
+			}
+		}  // for z, x
+	}  // for y
+	
+	// TODO: Turn sponge next to lava into stone
+	
+	// a_Lake.SaveToSchematicFile(Printf("Lake_%d_%d.schematic", a_ChunkX, a_ChunkZ));
+}
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cStructGenDirectOverhangs:
+
+cStructGenDirectOverhangs::cStructGenDirectOverhangs(int a_Seed) :
+	m_Noise1(a_Seed),
+	m_Noise2(a_Seed + 1000)
+{
+}
+
+
+
+
+
+void cStructGenDirectOverhangs::GenStructures(cChunkDesc & a_ChunkDesc)
+{
+	// If there is no column of the wanted biome, bail out:
+	if (!HasWantedBiome(a_ChunkDesc))
+	{
+		return;
+	}
+	
+	HEIGHTTYPE MaxHeight = a_ChunkDesc.GetMaxHeight();
+
+	const int SEGMENT_HEIGHT = 8;
+	const int INTERPOL_X = 16;  // Must be a divisor of 16
+	const int INTERPOL_Z = 16;  // Must be a divisor of 16
+	// Interpolate the chunk in 16 * SEGMENT_HEIGHT * 16 "segments", each SEGMENT_HEIGHT blocks high and each linearly interpolated separately.
+	// Have two buffers, one for the lowest floor and one for the highest floor, so that Y-interpolation can be done between them
+	// Then swap the buffers and use the previously-top one as the current-bottom, without recalculating it.
+	
+	int FloorBuf1[17 * 17];
+	int FloorBuf2[17 * 17];
+	int * FloorHi = FloorBuf1;
+	int * FloorLo = FloorBuf2;
+	int BaseX = a_ChunkDesc.GetChunkX() * cChunkDef::Width;
+	int BaseZ = a_ChunkDesc.GetChunkZ() * cChunkDef::Width;
+	int BaseY = 63;
+	
+	// Interpolate the lowest floor:
+	for (int z = 0; z <= 16 / INTERPOL_Z; z++) for (int x = 0; x <= 16 / INTERPOL_X; x++)
+	{
+		FloorLo[INTERPOL_X * x + 17 * INTERPOL_Z * z] = 
+			m_Noise1.IntNoise3DInt(BaseX + INTERPOL_X * x, BaseY, BaseZ + INTERPOL_Z * z) * 
+			m_Noise2.IntNoise3DInt(BaseX + INTERPOL_X * x, BaseY, BaseZ + INTERPOL_Z * z) /
+			256;
+	}  // for x, z - FloorLo[]
+	LinearUpscale2DArrayInPlace(FloorLo, 17, 17, INTERPOL_X, INTERPOL_Z);
+	
+	// Interpolate segments:
+	for (int Segment = BaseY; Segment < MaxHeight; Segment += SEGMENT_HEIGHT)
+	{
+		// First update the high floor:
+		for (int z = 0; z <= 16 / INTERPOL_Z; z++) for (int x = 0; x <= 16 / INTERPOL_X; x++)
+		{
+			FloorHi[INTERPOL_X * x + 17 * INTERPOL_Z * z] =
+				m_Noise1.IntNoise3DInt(BaseX + INTERPOL_X * x, Segment + SEGMENT_HEIGHT, BaseZ + INTERPOL_Z * z) *
+				m_Noise2.IntNoise3DInt(BaseX + INTERPOL_Z * x, Segment + SEGMENT_HEIGHT, BaseZ + INTERPOL_Z * z) /
+				256;
+		}  // for x, z - FloorLo[]
+		LinearUpscale2DArrayInPlace(FloorHi, 17, 17, INTERPOL_X, INTERPOL_Z);
+		
+		// Interpolate between FloorLo and FloorHi:
+		for (int z = 0; z < 16; z++) for (int x = 0; x < 16; x++)
+		{
+			switch (a_ChunkDesc.GetBiome(x, z))
+			{
+				case biExtremeHills:
+				case biExtremeHillsEdge:
+				{
+					int Lo = FloorLo[x + 17 * z] / 256;
+					int Hi = FloorHi[x + 17 * z] / 256;
+					for (int y = 0; y < SEGMENT_HEIGHT; y++)
+					{
+						int Val = Lo + (Hi - Lo) * y / SEGMENT_HEIGHT;
+						if (Val < 0)
+						{
+							a_ChunkDesc.SetBlockType(x, y + Segment, z, E_BLOCK_AIR);
+						}
+					}  // for y
+					break;
+				}
+			}  // switch (biome)
+		}  // for z, x
+		
+		// Swap the floors:
+		std::swap(FloorLo, FloorHi);
+	}
+}
+
+
+
+
+
+bool cStructGenDirectOverhangs::HasWantedBiome(cChunkDesc & a_ChunkDesc) const
+{
+	cChunkDef::BiomeMap & Biomes = a_ChunkDesc.GetBiomeMap();
+	for (int i = 0; i < ARRAYCOUNT(Biomes); i++)
+	{
+		switch (Biomes[i])
+		{
+			case biExtremeHills:
+			case biExtremeHillsEdge:
+			{
+				return true;
+			}
+		}
+	}  // for i
+	return false;
+}
+
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// cStructGenDistortedMembraneOverhangs:
+
+cStructGenDistortedMembraneOverhangs::cStructGenDistortedMembraneOverhangs(int a_Seed) :
+	m_NoiseX(a_Seed + 1000),
+	m_NoiseY(a_Seed + 2000),
+	m_NoiseZ(a_Seed + 3000),
+	m_NoiseH(a_Seed + 4000)
+{
+}
+
+
+
+
+
+void cStructGenDistortedMembraneOverhangs::GenStructures(cChunkDesc & a_ChunkDesc)
+{
+	const NOISE_DATATYPE Frequency = (NOISE_DATATYPE)16;
+	const NOISE_DATATYPE Amount = (NOISE_DATATYPE)1;
+	for (int y = 50; y < 128; y++)
+	{
+		NOISE_DATATYPE NoiseY = (NOISE_DATATYPE)y / 32;
+		// TODO: proper water level - where to get?
+		BLOCKTYPE ReplacementBlock = (y > 62) ? E_BLOCK_AIR : E_BLOCK_STATIONARY_WATER;
+		for (int z = 0; z < cChunkDef::Width; z++)
+		{
+			NOISE_DATATYPE NoiseZ = ((NOISE_DATATYPE)(a_ChunkDesc.GetChunkZ() * cChunkDef::Width + z)) / Frequency;
+			for (int x = 0; x < cChunkDef::Width; x++)
+			{
+				NOISE_DATATYPE NoiseX = ((NOISE_DATATYPE)(a_ChunkDesc.GetChunkX() * cChunkDef::Width + x)) / Frequency;
+				NOISE_DATATYPE DistortX = m_NoiseX.CubicNoise3D(NoiseX, NoiseY, NoiseZ) * Amount;
+				NOISE_DATATYPE DistortY = m_NoiseY.CubicNoise3D(NoiseX, NoiseY, NoiseZ) * Amount;
+				NOISE_DATATYPE DistortZ = m_NoiseZ.CubicNoise3D(NoiseX, NoiseY, NoiseZ) * Amount;
+				int MembraneHeight = 96 - (int)((DistortY + m_NoiseH.CubicNoise2D(NoiseX + DistortX, NoiseZ + DistortZ)) * 30);
+				if (MembraneHeight < y)
+				{
+					a_ChunkDesc.SetBlockType(x, y, z, ReplacementBlock);
+				}
+			}  // for y
+		}  // for x
+	}  // for z
+}
+
+
+
+