Mapgen: Combine generateBiomes, dustTopNodes, and generateCaves

This commit condenses the above methods into a single implementation used by
V7, V5, Flat, Fractal, and Valleys mapgens and introduces MapgenBasic.

12 files changed, 316 insertions, 1161 deletions

diff --git a/src/mapgen.cpp b/src/mapgen.cpp
index e269bf454..f491ed9eb 100644
--- a/src/mapgen.cpp
+++ b/src/mapgen.cpp
@@ -39,6 +39,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/numeric.h"
 #include "filesys.h"
 #include "log.h"
+#include "cavegen.h"
 
 FlagDesc flagdesc_mapgen[] = {
 	{"trees",       MG_TREES},
@@ -370,6 +371,241 @@ void Mapgen::spreadLight(v3s16 nmin, v3s16 nmax)
 
 
 ////
+//// MapgenBasic
+////
+
+MapgenBasic::MapgenBasic(int mapgenid, MapgenParams *params, EmergeManager *emerge)
+	: Mapgen(mapgenid, params, emerge)
+{
+
+}
+
+MgStoneType MapgenBasic::generateBiomes()
+{
+	v3s16 em = vm->m_area.getExtent();
+	u32 index = 0;
+	MgStoneType stone_type = STONE;
+
+	for (s16 z = node_min.Z; z <= node_max.Z; z++)
+	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
+		Biome *biome = NULL;
+		u16 depth_top = 0;
+		u16 base_filler = 0;
+		u16 depth_water_top = 0;
+		u32 vi = vm->m_area.index(x, node_max.Y, z);
+
+		// Check node at base of mapchunk above, either a node of a previously
+		// generated mapchunk or if not, a node of overgenerated base terrain.
+		content_t c_above = vm->m_data[vi + em.X].getContent();
+		bool air_above = c_above == CONTENT_AIR;
+		bool water_above = (c_above == c_water_source || c_above == c_river_water_source);
+
+		// If there is air or water above enable top/filler placement, otherwise force
+		// nplaced to stone level by setting a number exceeding any possible filler depth.
+		u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
+
+		for (s16 y = node_max.Y; y >= node_min.Y; y--) {
+			content_t c = vm->m_data[vi].getContent();
+
+			// Biome is recalculated each time an upper surface is detected while
+			// working down a column. The selected biome then remains in effect for
+			// all nodes below until the next surface and biome recalculation.
+			// Biome is recalculated:
+			// 1. At the surface of stone below air or water.
+			// 2. At the surface of water below air.
+			// 3. When stone or water is detected but biome has not yet been calculated.
+			if ((c == c_stone && (air_above || water_above || !biome))
+					|| ((c == c_water_source || c == c_river_water_source)
+						&& (air_above || !biome))) {
+				biome = biomegen->getBiomeAtIndex(index, y);
+
+				depth_top = biome->depth_top;
+				base_filler = MYMAX(depth_top
+						+ biome->depth_filler
+						+ noise_filler_depth->result[index], 0.f);
+				depth_water_top = biome->depth_water_top;
+
+				// Detect stone type for dungeons during every biome calculation.
+				// This is more efficient than detecting per-node and will not
+				// miss any desert stone or sandstone biomes.
+				if (biome->c_stone == c_desert_stone)
+					stone_type = DESERT_STONE;
+				else if (biome->c_stone == c_sandstone)
+					stone_type = SANDSTONE;
+			}
+
+			if (c == c_stone) {
+				content_t c_below = vm->m_data[vi - em.X].getContent();
+
+				// If the node below isn't solid, make this node stone, so that
+				// any top/filler nodes above are structurally supported.
+				// This is done by aborting the cycle of top/filler placement
+				// immediately by forcing nplaced to stone level.
+				if (c_below == CONTENT_AIR
+						|| c_below == c_water_source
+						|| c_below == c_river_water_source)
+					nplaced = U16_MAX;
+
+				if (nplaced < depth_top) {
+					vm->m_data[vi] = MapNode(biome->c_top);
+					nplaced++;
+				} else if (nplaced < base_filler) {
+					vm->m_data[vi] = MapNode(biome->c_filler);
+					nplaced++;
+				} else {
+					vm->m_data[vi] = MapNode(biome->c_stone);
+				}
+
+				air_above = false;
+				water_above = false;
+			} else if (c == c_water_source) {
+				vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top))
+						? biome->c_water_top : biome->c_water);
+				nplaced = 0;  // Enable top/filler placement for next surface
+				air_above = false;
+				water_above = true;
+			} else if (c == c_river_water_source) {
+				vm->m_data[vi] = MapNode(biome->c_river_water);
+				nplaced = depth_top;  // Enable filler placement for next surface
+				air_above = false;
+				water_above = true;
+			} else if (c == CONTENT_AIR) {
+				nplaced = 0;  // Enable top/filler placement for next surface
+				air_above = true;
+				water_above = false;
+			} else {  // Possible various nodes overgenerated from neighbouring mapchunks
+				nplaced = U16_MAX;  // Disable top/filler placement
+				air_above = false;
+				water_above = false;
+			}
+
+			vm->m_area.add_y(em, vi, -1);
+		}
+	}
+
+	return stone_type;
+}
+
+
+void MapgenBasic::dustTopNodes()
+{
+	if (node_max.Y < water_level)
+		return;
+
+	v3s16 em = vm->m_area.getExtent();
+	u32 index = 0;
+
+	for (s16 z = node_min.Z; z <= node_max.Z; z++)
+	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
+		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
+
+		if (biome->c_dust == CONTENT_IGNORE)
+			continue;
+
+		u32 vi = vm->m_area.index(x, full_node_max.Y, z);
+		content_t c_full_max = vm->m_data[vi].getContent();
+		s16 y_start;
+
+		if (c_full_max == CONTENT_AIR) {
+			y_start = full_node_max.Y - 1;
+		} else if (c_full_max == CONTENT_IGNORE) {
+			vi = vm->m_area.index(x, node_max.Y + 1, z);
+			content_t c_max = vm->m_data[vi].getContent();
+
+			if (c_max == CONTENT_AIR)
+				y_start = node_max.Y;
+			else
+				continue;
+		} else {
+			continue;
+		}
+
+		vi = vm->m_area.index(x, y_start, z);
+		for (s16 y = y_start; y >= node_min.Y - 1; y--) {
+			if (vm->m_data[vi].getContent() != CONTENT_AIR)
+				break;
+
+			vm->m_area.add_y(em, vi, -1);
+		}
+
+		content_t c = vm->m_data[vi].getContent();
+		if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
+			vm->m_area.add_y(em, vi, 1);
+			vm->m_data[vi] = MapNode(biome->c_dust);
+		}
+	}
+}
+
+
+void MapgenBasic::generateCaves(s16 max_stone_y, s16 large_cave_depth)
+{
+	if (max_stone_y < node_min.Y)
+		return;
+
+	noise_cave1->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
+	noise_cave2->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
+
+	v3s16 em = vm->m_area.getExtent();
+	u32 index2d = 0;
+
+	for (s16 z = node_min.Z; z <= node_max.Z; z++)
+	for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
+		bool column_is_open = false;  // Is column open to overground
+		bool is_tunnel = false;  // Is tunnel or tunnel floor
+		u32 vi = vm->m_area.index(x, node_max.Y, z);
+		u32 index3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride +
+			(x - node_min.X);
+		// Biome of column
+		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
+
+		// Don't excavate the overgenerated stone at node_max.Y + 1,
+		// this creates a 'roof' over the tunnel, preventing light in
+		// tunnels at mapchunk borders when generating mapchunks upwards.
+		// This 'roof' is removed when the mapchunk above is generated.
+		for (s16 y = node_max.Y; y >= node_min.Y - 1; y--,
+				index3d -= ystride,
+				vm->m_area.add_y(em, vi, -1)) {
+
+			content_t c = vm->m_data[vi].getContent();
+			if (c == CONTENT_AIR || c == biome->c_water_top ||
+					c == biome->c_water) {
+				column_is_open = true;
+				continue;
+			}
+			// Ground
+			float d1 = contour(noise_cave1->result[index3d]);
+			float d2 = contour(noise_cave2->result[index3d]);
+
+			if (d1 * d2 > cave_width && ndef->get(c).is_ground_content) {
+				// In tunnel and ground content, excavate
+				vm->m_data[vi] = MapNode(CONTENT_AIR);
+				is_tunnel = true;
+			} else {
+				// Not in tunnel or not ground content
+				if (is_tunnel && column_is_open &&
+						(c == biome->c_filler || c == biome->c_stone))
+					// Tunnel entrance floor
+					vm->m_data[vi] = MapNode(biome->c_top);
+
+				column_is_open = false;
+				is_tunnel = false;
+			}
+		}
+	}
+
+	if (node_max.Y > large_cave_depth)
+		return;
+
+	PseudoRandom ps(blockseed + 21343);
+	u32 bruises_count = ps.range(0, 2);
+	for (u32 i = 0; i < bruises_count; i++) {
+		CaveV5 cave(this, &ps);       ////caves version varies  ---- todo- fix this!
+		cave.makeCave(node_min, node_max, max_stone_y);
+	}
+}
+
+
+////
 //// GenerateNotifier
 ////
 
diff --git a/src/mapgen.h b/src/mapgen.h
index 554ec6084..bee8e786a 100644
--- a/src/mapgen.h
+++ b/src/mapgen.h
@@ -46,6 +46,7 @@ extern FlagDesc flagdesc_gennotify[];
 class Biome;
 class BiomeGen;
 struct BiomeParams;
+class BiomeManager;
 class EmergeManager;
 class MapBlock;
 class VoxelManipulator;
@@ -137,6 +138,16 @@ struct MapgenParams {
 	void save(Settings &settings) const;
 };
 
+
+/*
+	Generic interface for map generators.  All mapgens must inherit this class.
+	If a feature exposed by a public member pointer is not supported by a
+	certain mapgen, it must be set to NULL.
+
+	Apart from makeChunk, getGroundLevelAtPoint, and getSpawnLevelAtPoint, all
+	methods can be used by constructing a Mapgen base class and setting the
+	appropriate public members (e.g. vm, ndef, and so on).
+*/
 class Mapgen {
 public:
 	int seed;
@@ -189,6 +200,51 @@ private:
 	DISABLE_CLASS_COPY(Mapgen);
 };
 
+/*
+	MapgenBasic is a Mapgen implementation that handles basic functionality
+	the majority of conventional mapgens will probably want to use, but isn't
+	generic enough to be included as part of the base Mapgen class (such as
+	generating biome terrain over terrain node skeletons, generating caves,
+	dungeons, etc.)
+
+	Inherit MapgenBasic instead of Mapgen to add this basic functionality to
+	your mapgen without having to reimplement it.  Feel free to override any of
+	these methods if you desire different or more advanced behavior.
+
+	Note that you must still create your own generateTerrain implementation when
+	inheriting MapgenBasic.
+*/
+class MapgenBasic : public Mapgen {
+public:
+	EmergeManager *m_emerge;
+	BiomeManager *bmgr;
+
+	Noise *noise_filler_depth;
+	Noise *noise_cave1;
+	Noise *noise_cave2;
+
+	v3s16 node_min;
+	v3s16 node_max;
+	v3s16 full_node_min;
+	v3s16 full_node_max;
+
+	content_t c_stone;
+	content_t c_water_source;
+	content_t c_river_water_source;
+	content_t c_desert_stone;
+	content_t c_sandstone;
+
+	int ystride;
+	int zstride_1d;
+	float cave_width;
+
+	MapgenBasic(int mapgenid, MapgenParams *params, EmergeManager *emerge);
+
+	virtual MgStoneType generateBiomes();
+	virtual void dustTopNodes();
+	virtual void generateCaves(s16 max_stone_y, s16 large_cave_depth);
+};
+
 struct MapgenFactory {
 	virtual Mapgen *createMapgen(int mgid, MapgenParams *params,
 		EmergeManager *emerge) = 0;
diff --git a/src/mapgen_flat.cpp b/src/mapgen_flat.cpp
index cb9aa9a8b..97f1c4b2a 100644
--- a/src/mapgen_flat.cpp
+++ b/src/mapgen_flat.cpp
@@ -50,7 +50,7 @@ FlagDesc flagdesc_mapgen_flat[] = {
 
 
 MapgenFlat::MapgenFlat(int mapgenid, MapgenParams *params, EmergeManager *emerge)
-	: Mapgen(mapgenid, params, emerge)
+	: MapgenBasic(mapgenid, params, emerge)
 {
 	this->m_emerge = emerge;
 	this->bmgr     = emerge->biomemgr;
@@ -248,7 +248,7 @@ void MapgenFlat::makeChunk(BlockMakeData *data)
 	MgStoneType stone_type = generateBiomes();
 
 	if (flags & MG_CAVES)
-		generateCaves(stone_surface_max_y);
+		generateCaves(stone_surface_max_y, large_cave_depth);
 
 	if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 		DungeonParams dp;
@@ -381,220 +381,3 @@ s16 MapgenFlat::generateTerrain()
 
 	return stone_surface_max_y;
 }
-
-
-MgStoneType MapgenFlat::generateBiomes()
-{
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-	MgStoneType stone_type = STONE;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = NULL;
-		u16 depth_top = 0;
-		u16 base_filler = 0;
-		u16 depth_water_top = 0;
-		u32 vi = vm->m_area.index(x, node_max.Y, z);
-
-		// Check node at base of mapchunk above, either a node of a previously
-		// generated mapchunk or if not, a node of overgenerated base terrain.
-		content_t c_above = vm->m_data[vi + em.X].getContent();
-		bool air_above = c_above == CONTENT_AIR;
-		bool water_above = c_above == c_water_source;
-
-		// If there is air or water above enable top/filler placement, otherwise force
-		// nplaced to stone level by setting a number exceeding any possible filler depth.
-		u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
-
-
-		for (s16 y = node_max.Y; y >= node_min.Y; y--) {
-			content_t c = vm->m_data[vi].getContent();
-
-			// Biome is recalculated each time an upper surface is detected while
-			// working down a column. The selected biome then remains in effect for
-			// all nodes below until the next surface and biome recalculation.
-			// Biome is recalculated:
-			// 1. At the surface of stone below air or water.
-			// 2. At the surface of water below air.
-			// 3. When stone or water is detected but biome has not yet been calculated.
-			if ((c == c_stone && (air_above || water_above || !biome)) ||
-					(c == c_water_source && (air_above || !biome))) {
-				biome = biomegen->getBiomeAtIndex(index, y);
-
-				depth_top = biome->depth_top;
-				base_filler = MYMAX(depth_top + biome->depth_filler
-					+ noise_filler_depth->result[index], 0);
-				depth_water_top = biome->depth_water_top;
-
-				// Detect stone type for dungeons during every biome calculation.
-				// This is more efficient than detecting per-node and will not
-				// miss any desert stone or sandstone biomes.
-				if (biome->c_stone == c_desert_stone)
-					stone_type = DESERT_STONE;
-				else if (biome->c_stone == c_sandstone)
-					stone_type = SANDSTONE;
-			}
-
-			if (c == c_stone) {
-				content_t c_below = vm->m_data[vi - em.X].getContent();
-
-				// If the node below isn't solid, make this node stone, so that
-				// any top/filler nodes above are structurally supported.
-				// This is done by aborting the cycle of top/filler placement
-				// immediately by forcing nplaced to stone level.
-				if (c_below == CONTENT_AIR || c_below == c_water_source)
-					nplaced = U16_MAX;
-
-				if (nplaced < depth_top) {
-					vm->m_data[vi] = MapNode(biome->c_top);
-					nplaced++;
-				} else if (nplaced < base_filler) {
-					vm->m_data[vi] = MapNode(biome->c_filler);
-					nplaced++;
-				} else {
-					vm->m_data[vi] = MapNode(biome->c_stone);
-				}
-
-				air_above = false;
-				water_above = false;
-			} else if (c == c_water_source) {
-				vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
-						biome->c_water_top : biome->c_water);
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = false;
-				water_above = true;
-			} else if (c == CONTENT_AIR) {
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = true;
-				water_above = false;
-			} else {  // Possible various nodes overgenerated from neighbouring mapchunks
-				nplaced = U16_MAX;  // Disable top/filler placement
-				air_above = false;
-				water_above = false;
-			}
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-	}
-
-	return stone_type;
-}
-
-
-void MapgenFlat::dustTopNodes()
-{
-	if (node_max.Y < water_level)
-		return;
-
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
-
-		if (biome->c_dust == CONTENT_IGNORE)
-			continue;
-
-		u32 vi = vm->m_area.index(x, full_node_max.Y, z);
-		content_t c_full_max = vm->m_data[vi].getContent();
-		s16 y_start;
-
-		if (c_full_max == CONTENT_AIR) {
-			y_start = full_node_max.Y - 1;
-		} else if (c_full_max == CONTENT_IGNORE) {
-			vi = vm->m_area.index(x, node_max.Y + 1, z);
-			content_t c_max = vm->m_data[vi].getContent();
-
-			if (c_max == CONTENT_AIR)
-				y_start = node_max.Y;
-			else
-				continue;
-		} else {
-			continue;
-		}
-
-		vi = vm->m_area.index(x, y_start, z);
-		for (s16 y = y_start; y >= node_min.Y - 1; y--) {
-			if (vm->m_data[vi].getContent() != CONTENT_AIR)
-				break;
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-
-		content_t c = vm->m_data[vi].getContent();
-		if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
-			vm->m_area.add_y(em, vi, 1);
-			vm->m_data[vi] = MapNode(biome->c_dust);
-		}
-	}
-}
-
-
-void MapgenFlat::generateCaves(s16 max_stone_y)
-{
-	if (max_stone_y < node_min.Y)
-		return;
-
-	noise_cave1->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
-	noise_cave2->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
-
-	v3s16 em = vm->m_area.getExtent();
-	u32 index2d = 0;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
-		bool column_is_open = false;  // Is column open to overground
-		bool is_tunnel = false;  // Is tunnel or tunnel floor
-		u32 vi = vm->m_area.index(x, node_max.Y, z);
-		u32 index3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride +
-			(x - node_min.X);
-		// Biome of column
-		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
-
-		// Don't excavate the overgenerated stone at node_max.Y + 1,
-		// this creates a 'roof' over the tunnel, preventing light in
-		// tunnels at mapchunk borders when generating mapchunks upwards.
-		// This 'roof' is removed when the mapchunk above is generated.
-		for (s16 y = node_max.Y; y >= node_min.Y - 1; y--,
-				index3d -= ystride,
-				vm->m_area.add_y(em, vi, -1)) {
-
-			content_t c = vm->m_data[vi].getContent();
-			if (c == CONTENT_AIR || c == biome->c_water_top ||
-					c == biome->c_water) {
-				column_is_open = true;
-				continue;
-			}
-			// Ground
-			float d1 = contour(noise_cave1->result[index3d]);
-			float d2 = contour(noise_cave2->result[index3d]);
-
-			if (d1 * d2 > cave_width && ndef->get(c).is_ground_content) {
-				// In tunnel and ground content, excavate
-				vm->m_data[vi] = MapNode(CONTENT_AIR);
-				is_tunnel = true;
-			} else {
-				// Not in tunnel or not ground content
-				if (is_tunnel && column_is_open &&
-						(c == biome->c_filler || c == biome->c_stone))
-					// Tunnel entrance floor
-					vm->m_data[vi] = MapNode(biome->c_top);
-
-				column_is_open = false;
-				is_tunnel = false;
-			}
-		}
-	}
-
-	if (node_max.Y > large_cave_depth)
-		return;
-
-	PseudoRandom ps(blockseed + 21343);
-	u32 bruises_count = ps.range(0, 2);
-	for (u32 i = 0; i < bruises_count; i++) {
-		CaveV5 cave(this, &ps);
-		cave.makeCave(node_min, node_max, max_stone_y);
-	}
-}
diff --git a/src/mapgen_flat.h b/src/mapgen_flat.h
index 53fd66a67..2b98c1f31 100644
--- a/src/mapgen_flat.h
+++ b/src/mapgen_flat.h
@@ -53,43 +53,19 @@ struct MapgenFlatParams : public MapgenSpecificParams {
 	void writeParams(Settings *settings) const;
 };
 
-class MapgenFlat : public Mapgen {
+class MapgenFlat : public MapgenBasic {
 public:
-	EmergeManager *m_emerge;
-	BiomeManager *bmgr;
-
-	int ystride;
-	int zstride_1d;
-
-	v3s16 node_min;
-	v3s16 node_max;
-	v3s16 full_node_min;
-	v3s16 full_node_max;
-
 	u32 spflags;
 	s16 ground_level;
 	s16 large_cave_depth;
-	float cave_width;
 	float lake_threshold;
 	float lake_steepness;
 	float hill_threshold;
 	float hill_steepness;
 	Noise *noise_terrain;
-	Noise *noise_filler_depth;
-	Noise *noise_cave1;
-	Noise *noise_cave2;
-
-	Noise *noise_heat;
-	Noise *noise_humidity;
-	Noise *noise_heat_blend;
-	Noise *noise_humidity_blend;
 
-	content_t c_stone;
-	content_t c_water_source;
 	content_t c_lava_source;
-	content_t c_desert_stone;
 	content_t c_ice;
-	content_t c_sandstone;
 
 	content_t c_cobble;
 	content_t c_stair_cobble;
@@ -104,9 +80,6 @@ public:
 	int getSpawnLevelAtPoint(v2s16 p);
 	void calculateNoise();
 	s16 generateTerrain();
-	MgStoneType generateBiomes();
-	void dustTopNodes();
-	void generateCaves(s16 max_stone_y);
 };
 
 struct MapgenFactoryFlat : public MapgenFactory {
diff --git a/src/mapgen_fractal.cpp b/src/mapgen_fractal.cpp
index 9671a2143..81e162072 100644
--- a/src/mapgen_fractal.cpp
+++ b/src/mapgen_fractal.cpp
@@ -48,7 +48,7 @@ FlagDesc flagdesc_mapgen_fractal[] = {
 
 
 MapgenFractal::MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *emerge)
-	: Mapgen(mapgenid, params, emerge)
+	: MapgenBasic(mapgenid, params, emerge)
 {
 	this->m_emerge = emerge;
 	this->bmgr     = emerge->biomemgr;
@@ -264,7 +264,7 @@ void MapgenFractal::makeChunk(BlockMakeData *data)
 	MgStoneType stone_type = generateBiomes();
 
 	if (flags & MG_CAVES)
-		generateCaves(stone_surface_max_y);
+		generateCaves(stone_surface_max_y, MGFRACTAL_LARGE_CAVE_DEPTH);
 
 	if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 		DungeonParams dp;
@@ -505,220 +505,3 @@ s16 MapgenFractal::generateTerrain()
 
 	return stone_surface_max_y;
 }
-
-
-MgStoneType MapgenFractal::generateBiomes()
-{
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-	MgStoneType stone_type = STONE;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = NULL;
-		u16 depth_top = 0;
-		u16 base_filler = 0;
-		u16 depth_water_top = 0;
-		u32 vi = vm->m_area.index(x, node_max.Y, z);
-
-		// Check node at base of mapchunk above, either a node of a previously
-		// generated mapchunk or if not, a node of overgenerated base terrain.
-		content_t c_above = vm->m_data[vi + em.X].getContent();
-		bool air_above = c_above == CONTENT_AIR;
-		bool water_above = c_above == c_water_source;
-
-		// If there is air or water above enable top/filler placement, otherwise force
-		// nplaced to stone level by setting a number exceeding any possible filler depth.
-		u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
-
-
-		for (s16 y = node_max.Y; y >= node_min.Y; y--) {
-			content_t c = vm->m_data[vi].getContent();
-
-			// Biome is recalculated each time an upper surface is detected while
-			// working down a column. The selected biome then remains in effect for
-			// all nodes below until the next surface and biome recalculation.
-			// Biome is recalculated:
-			// 1. At the surface of stone below air or water.
-			// 2. At the surface of water below air.
-			// 3. When stone or water is detected but biome has not yet been calculated.
-			if ((c == c_stone && (air_above || water_above || !biome)) ||
-					(c == c_water_source && (air_above || !biome))) {
-				biome = biomegen->getBiomeAtIndex(index, y);
-
-				depth_top = biome->depth_top;
-				base_filler = MYMAX(depth_top + biome->depth_filler
-					+ noise_filler_depth->result[index], 0);
-				depth_water_top = biome->depth_water_top;
-
-				// Detect stone type for dungeons during every biome calculation.
-				// This is more efficient than detecting per-node and will not
-				// miss any desert stone or sandstone biomes.
-				if (biome->c_stone == c_desert_stone)
-					stone_type = DESERT_STONE;
-				else if (biome->c_stone == c_sandstone)
-					stone_type = SANDSTONE;
-			}
-
-			if (c == c_stone) {
-				content_t c_below = vm->m_data[vi - em.X].getContent();
-
-				// If the node below isn't solid, make this node stone, so that
-				// any top/filler nodes above are structurally supported.
-				// This is done by aborting the cycle of top/filler placement
-				// immediately by forcing nplaced to stone level.
-				if (c_below == CONTENT_AIR || c_below == c_water_source)
-					nplaced = U16_MAX;
-
-				if (nplaced < depth_top) {
-					vm->m_data[vi] = MapNode(biome->c_top);
-					nplaced++;
-				} else if (nplaced < base_filler) {
-					vm->m_data[vi] = MapNode(biome->c_filler);
-					nplaced++;
-				} else {
-					vm->m_data[vi] = MapNode(biome->c_stone);
-				}
-
-				air_above = false;
-				water_above = false;
-			} else if (c == c_water_source) {
-				vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
-						biome->c_water_top : biome->c_water);
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = false;
-				water_above = true;
-			} else if (c == CONTENT_AIR) {
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = true;
-				water_above = false;
-			} else {  // Possible various nodes overgenerated from neighbouring mapchunks
-				nplaced = U16_MAX;  // Disable top/filler placement
-				air_above = false;
-				water_above = false;
-			}
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-	}
-
-	return stone_type;
-}
-
-
-void MapgenFractal::dustTopNodes()
-{
-	if (node_max.Y < water_level)
-		return;
-
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
-
-		if (biome->c_dust == CONTENT_IGNORE)
-			continue;
-
-		u32 vi = vm->m_area.index(x, full_node_max.Y, z);
-		content_t c_full_max = vm->m_data[vi].getContent();
-		s16 y_start;
-
-		if (c_full_max == CONTENT_AIR) {
-			y_start = full_node_max.Y - 1;
-		} else if (c_full_max == CONTENT_IGNORE) {
-			vi = vm->m_area.index(x, node_max.Y + 1, z);
-			content_t c_max = vm->m_data[vi].getContent();
-
-			if (c_max == CONTENT_AIR)
-				y_start = node_max.Y;
-			else
-				continue;
-		} else {
-			continue;
-		}
-
-		vi = vm->m_area.index(x, y_start, z);
-		for (s16 y = y_start; y >= node_min.Y - 1; y--) {
-			if (vm->m_data[vi].getContent() != CONTENT_AIR)
-				break;
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-
-		content_t c = vm->m_data[vi].getContent();
-		if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
-			vm->m_area.add_y(em, vi, 1);
-			vm->m_data[vi] = MapNode(biome->c_dust);
-		}
-	}
-}
-
-
-void MapgenFractal::generateCaves(s16 max_stone_y)
-{
-	if (max_stone_y < node_min.Y)
-		return;
-
-	noise_cave1->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
-	noise_cave2->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
-
-	v3s16 em = vm->m_area.getExtent();
-	u32 index2d = 0;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
-		bool column_is_open = false;  // Is column open to overground
-		bool is_tunnel = false;  // Is tunnel or tunnel floor
-		u32 vi = vm->m_area.index(x, node_max.Y, z);
-		u32 index3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride +
-			(x - node_min.X);
-		// Biome of column
-		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
-
-		// Don't excavate the overgenerated stone at node_max.Y + 1,
-		// this creates a 'roof' over the tunnel, preventing light in
-		// tunnels at mapchunk borders when generating mapchunks upwards.
-		// This 'roof' is removed when the mapchunk above is generated.
-		for (s16 y = node_max.Y; y >= node_min.Y - 1; y--,
-				index3d -= ystride,
-				vm->m_area.add_y(em, vi, -1)) {
-
-			content_t c = vm->m_data[vi].getContent();
-			if (c == CONTENT_AIR || c == biome->c_water_top ||
-					c == biome->c_water) {
-				column_is_open = true;
-				continue;
-			}
-			// Ground
-			float d1 = contour(noise_cave1->result[index3d]);
-			float d2 = contour(noise_cave2->result[index3d]);
-
-			if (d1 * d2 > cave_width && ndef->get(c).is_ground_content) {
-				// In tunnel and ground content, excavate
-				vm->m_data[vi] = MapNode(CONTENT_AIR);
-				is_tunnel = true;
-			} else {
-				// Not in tunnel or not ground content
-				if (is_tunnel && column_is_open &&
-						(c == biome->c_filler || c == biome->c_stone))
-					// Tunnel entrance floor
-					vm->m_data[vi] = MapNode(biome->c_top);
-
-				column_is_open = false;
-				is_tunnel = false;
-			}
-		}
-	}
-
-	if (node_max.Y > MGFRACTAL_LARGE_CAVE_DEPTH)
-		return;
-
-	PseudoRandom ps(blockseed + 21343);
-	u32 bruises_count = ps.range(0, 2);
-	for (u32 i = 0; i < bruises_count; i++) {
-		CaveV5 cave(this, &ps);
-		cave.makeCave(node_min, node_max, max_stone_y);
-	}
-}
diff --git a/src/mapgen_fractal.h b/src/mapgen_fractal.h
index a0e51b2c6..176885d46 100644
--- a/src/mapgen_fractal.h
+++ b/src/mapgen_fractal.h
@@ -57,23 +57,12 @@ struct MapgenFractalParams : public MapgenSpecificParams {
 	void writeParams(Settings *settings) const;
 };
 
-class MapgenFractal : public Mapgen {
+class MapgenFractal : public MapgenBasic {
 public:
-	EmergeManager *m_emerge;
-	BiomeManager *bmgr;
-
-	int ystride;
-	int zstride_1d;
 	u16 formula;
 	bool julia;
 
-	v3s16 node_min;
-	v3s16 node_max;
-	v3s16 full_node_min;
-	v3s16 full_node_max;
-
 	u32 spflags;
-	float cave_width;
 	u16 fractal;
 	u16 iterations;
 	v3f scale;
@@ -84,16 +73,9 @@ public:
 	float julia_z;
 	float julia_w;
 	Noise *noise_seabed;
-	Noise *noise_filler_depth;
-	Noise *noise_cave1;
-	Noise *noise_cave2;
 
-	content_t c_stone;
-	content_t c_water_source;
 	content_t c_lava_source;
-	content_t c_desert_stone;
 	content_t c_ice;
-	content_t c_sandstone;
 
 	content_t c_cobble;
 	content_t c_stair_cobble;
@@ -109,9 +91,6 @@ public:
 	void calculateNoise();
 	bool getFractalAtPoint(s16 x, s16 y, s16 z);
 	s16 generateTerrain();
-	MgStoneType generateBiomes();
-	void dustTopNodes();
-	void generateCaves(s16 max_stone_y);
 };
 
 struct MapgenFactoryFractal : public MapgenFactory {
diff --git a/src/mapgen_v5.cpp b/src/mapgen_v5.cpp
index 829a1f432..7698af825 100644
--- a/src/mapgen_v5.cpp
+++ b/src/mapgen_v5.cpp
@@ -46,7 +46,7 @@ FlagDesc flagdesc_mapgen_v5[] = {
 
 
 MapgenV5::MapgenV5(int mapgenid, MapgenParams *params, EmergeManager *emerge)
-	: Mapgen(mapgenid, params, emerge)
+	: MapgenBasic(mapgenid, params, emerge)
 {
 	this->m_emerge = emerge;
 	this->bmgr     = emerge->biomemgr;
@@ -245,7 +245,7 @@ void MapgenV5::makeChunk(BlockMakeData *data)
 
 	// Generate caves
 	if ((flags & MG_CAVES) && (stone_surface_max_y >= node_min.Y))
-		generateCaves(stone_surface_max_y);
+		generateCaves(stone_surface_max_y, MGV5_LARGE_CAVE_DEPTH);
 
 	// Generate dungeons and desert temples
 	if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
@@ -391,220 +391,3 @@ int MapgenV5::generateBaseTerrain()
 
 	return stone_surface_max_y;
 }
-
-
-MgStoneType MapgenV5::generateBiomes()
-{
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-	MgStoneType stone_type = STONE;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = NULL;
-		u16 depth_top = 0;
-		u16 base_filler = 0;
-		u16 depth_water_top = 0;
-		u32 vi = vm->m_area.index(x, node_max.Y, z);
-
-		// Check node at base of mapchunk above, either a node of a previously
-		// generated mapchunk or if not, a node of overgenerated base terrain.
-		content_t c_above = vm->m_data[vi + em.X].getContent();
-		bool air_above = c_above == CONTENT_AIR;
-		bool water_above = c_above == c_water_source;
-
-		// If there is air or water above enable top/filler placement, otherwise force
-		// nplaced to stone level by setting a number exceeding any possible filler depth.
-		u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
-
-		for (s16 y = node_max.Y; y >= node_min.Y; y--) {
-			content_t c = vm->m_data[vi].getContent();
-
-			// Biome is recalculated each time an upper surface is detected while
-			// working down a column. The selected biome then remains in effect for
-			// all nodes below until the next surface and biome recalculation.
-			// Biome is recalculated:
-			// 1. At the surface of stone below air or water.
-			// 2. At the surface of water below air.
-			// 3. When stone or water is detected but biome has not yet been calculated.
-			if ((c == c_stone && (air_above || water_above || !biome)) ||
-					(c == c_water_source && (air_above || !biome))) {
-				biome = biomegen->getBiomeAtIndex(index, y);
-
-				depth_top = biome->depth_top;
-				base_filler = MYMAX(depth_top + biome->depth_filler
-						+ noise_filler_depth->result[index], 0);
-				depth_water_top = biome->depth_water_top;
-
-				// Detect stone type for dungeons during every biome calculation.
-				// This is more efficient than detecting per-node and will not
-				// miss any desert stone or sandstone biomes.
-				if (biome->c_stone == c_desert_stone)
-					stone_type = DESERT_STONE;
-				else if (biome->c_stone == c_sandstone)
-					stone_type = SANDSTONE;
-			}
-
-			if (c == c_stone) {
-				content_t c_below = vm->m_data[vi - em.X].getContent();
-
-				// If the node below isn't solid, make this node stone, so that
-				// any top/filler nodes above are structurally supported.
-				// This is done by aborting the cycle of top/filler placement
-				// immediately by forcing nplaced to stone level.
-				if (c_below == CONTENT_AIR || c_below == c_water_source)
-					nplaced = U16_MAX;
-
-				if (nplaced < depth_top) {
-					vm->m_data[vi] = MapNode(biome->c_top);
-					nplaced++;
-				} else if (nplaced < base_filler) {
-					vm->m_data[vi] = MapNode(biome->c_filler);
-					nplaced++;
-				} else {
-					vm->m_data[vi] = MapNode(biome->c_stone);
-				}
-
-				air_above = false;
-				water_above = false;
-			} else if (c == c_water_source) {
-				vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
-						biome->c_water_top : biome->c_water);
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = false;
-				water_above = true;
-			} else if (c == CONTENT_AIR) {
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = true;
-				water_above = false;
-			} else {  // Possible various nodes overgenerated from neighbouring mapchunks
-				nplaced = U16_MAX;  // Disable top/filler placement
-				air_above = false;
-				water_above = false;
-			}
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-	}
-
-	return stone_type;
-}
-
-
-void MapgenV5::dustTopNodes()
-{
-	if (node_max.Y < water_level)
-		return;
-
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
-
-		if (biome->c_dust == CONTENT_IGNORE)
-			continue;
-
-		u32 vi = vm->m_area.index(x, full_node_max.Y, z);
-		content_t c_full_max = vm->m_data[vi].getContent();
-		s16 y_start;
-
-		if (c_full_max == CONTENT_AIR) {
-			y_start = full_node_max.Y - 1;
-		} else if (c_full_max == CONTENT_IGNORE) {
-			vi = vm->m_area.index(x, node_max.Y + 1, z);
-			content_t c_max = vm->m_data[vi].getContent();
-
-			if (c_max == CONTENT_AIR)
-				y_start = node_max.Y;
-			else
-				continue;
-		} else {
-			continue;
-		}
-
-		vi = vm->m_area.index(x, y_start, z);
-		for (s16 y = y_start; y >= node_min.Y - 1; y--) {
-			if (vm->m_data[vi].getContent() != CONTENT_AIR)
-				break;
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-
-		content_t c = vm->m_data[vi].getContent();
-		if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
-			vm->m_area.add_y(em, vi, 1);
-			vm->m_data[vi] = MapNode(biome->c_dust);
-		}
-	}
-}
-
-
-void MapgenV5::generateCaves(int max_stone_y)
-{
-	if (max_stone_y < node_min.Y)
-		return;
-
-	noise_cave1->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
-	noise_cave2->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
-
-	v3s16 em = vm->m_area.getExtent();
-	u32 index2d = 0;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
-		bool column_is_open = false;  // Is column open to overground
-		bool is_tunnel = false;  // Is tunnel or tunnel floor
-		// Indexes at column top (node_max.Y)
-		u32 vi = vm->m_area.index(x, node_max.Y, z);
-		u32 index3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride +
-			(x - node_min.X);
-		// Biome of column
-		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
-
-		// Don't excavate the overgenerated stone at node_max.Y + 1,
-		// this creates a 'roof' over the tunnel, preventing light in
-		// tunnels at mapchunk borders when generating mapchunks upwards.
-		// This 'roof' is removed when the mapchunk above is generated.
-		for (s16 y = node_max.Y; y >= node_min.Y - 1; y--,
-				index3d -= ystride,
-				vm->m_area.add_y(em, vi, -1)) {
-
-			content_t c = vm->m_data[vi].getContent();
-			if (c == CONTENT_AIR || c == biome->c_water_top ||
-					c == biome->c_water) {
-				column_is_open = true;
-				continue;
-			}
-			// Ground
-			float d1 = contour(noise_cave1->result[index3d]);
-			float d2 = contour(noise_cave2->result[index3d]);
-
-			if (d1 * d2 > cave_width && ndef->get(c).is_ground_content) {
-				// In tunnel and ground content, excavate
-				vm->m_data[vi] = MapNode(CONTENT_AIR);
-				is_tunnel = true;
-			} else {
-				// Not in tunnel or not ground content
-				if (is_tunnel && column_is_open &&
-						(c == biome->c_filler || c == biome->c_stone))
-					// Tunnel entrance floor
-					vm->m_data[vi] = MapNode(biome->c_top);
-
-				column_is_open = false;
-				is_tunnel = false;
-			}
-		}
-	}
-
-	if (node_max.Y > MGV5_LARGE_CAVE_DEPTH)
-		return;
-
-	PseudoRandom ps(blockseed + 21343);
-	u32 bruises_count = ps.range(0, 2);
-	for (u32 i = 0; i < bruises_count; i++) {
-		CaveV5 cave(this, &ps);
-		cave.makeCave(node_min, node_max, max_stone_y);
-	}
-}
diff --git a/src/mapgen_v5.h b/src/mapgen_v5.h
index eef3da617..99836b23e 100644
--- a/src/mapgen_v5.h
+++ b/src/mapgen_v5.h
@@ -48,34 +48,15 @@ struct MapgenV5Params : public MapgenSpecificParams {
 };
 
 
-class MapgenV5 : public Mapgen {
+class MapgenV5 : public MapgenBasic {
 public:
-	EmergeManager *m_emerge;
-	BiomeManager *bmgr;
-
-	int ystride;
-	int zstride_1d;
-
-	v3s16 node_min;
-	v3s16 node_max;
-	v3s16 full_node_min;
-	v3s16 full_node_max;
-
 	u32 spflags;
-	float cave_width;
-	Noise *noise_filler_depth;
 	Noise *noise_factor;
 	Noise *noise_height;
-	Noise *noise_cave1;
-	Noise *noise_cave2;
 	Noise *noise_ground;
 
-	content_t c_stone;
-	content_t c_water_source;
 	content_t c_lava_source;
-	content_t c_desert_stone;
 	content_t c_ice;
-	content_t c_sandstone;
 
 	content_t c_cobble;
 	content_t c_stair_cobble;
@@ -90,9 +71,6 @@ public:
 	int getSpawnLevelAtPoint(v2s16 p);
 	void calculateNoise();
 	int generateBaseTerrain();
-	MgStoneType generateBiomes();
-	void generateCaves(int max_stone_y);
-	void dustTopNodes();
 };
 
 
diff --git a/src/mapgen_v7.cpp b/src/mapgen_v7.cpp
index fddb34682..ee609bc95 100644
--- a/src/mapgen_v7.cpp
+++ b/src/mapgen_v7.cpp
@@ -51,7 +51,7 @@ FlagDesc flagdesc_mapgen_v7[] = {
 
 
 MapgenV7::MapgenV7(int mapgenid, MapgenParams *params, EmergeManager *emerge)
-	: Mapgen(mapgenid, params, emerge)
+	: MapgenBasic(mapgenid, params, emerge)
 {
 	this->m_emerge = emerge;
 	this->bmgr     = emerge->biomemgr;
@@ -276,7 +276,7 @@ void MapgenV7::makeChunk(BlockMakeData *data)
 	MgStoneType stone_type = generateBiomes();
 
 	if (flags & MG_CAVES)
-		generateCaves(stone_surface_max_y);
+		generateCaves(stone_surface_max_y, water_level);
 
 	if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
 		DungeonParams dp;
@@ -517,225 +517,13 @@ void MapgenV7::generateRidgeTerrain()
 }
 
 
-MgStoneType MapgenV7::generateBiomes()
-{
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-	MgStoneType stone_type = STONE;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = NULL;
-		u16 depth_top = 0;
-		u16 base_filler = 0;
-		u16 depth_water_top = 0;
-		u32 vi = vm->m_area.index(x, node_max.Y, z);
-
-		// Check node at base of mapchunk above, either a node of a previously
-		// generated mapchunk or if not, a node of overgenerated base terrain.
-		content_t c_above = vm->m_data[vi + em.X].getContent();
-		bool air_above = c_above == CONTENT_AIR;
-		bool water_above = c_above == c_water_source;
-
-		// If there is air or water above enable top/filler placement, otherwise force
-		// nplaced to stone level by setting a number exceeding any possible filler depth.
-		u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
-
-		for (s16 y = node_max.Y; y >= node_min.Y; y--) {
-			content_t c = vm->m_data[vi].getContent();
-
-			// Biome is recalculated each time an upper surface is detected while
-			// working down a column. The selected biome then remains in effect for
-			// all nodes below until the next surface and biome recalculation.
-			// Biome is recalculated:
-			// 1. At the surface of stone below air or water.
-			// 2. At the surface of water below air.
-			// 3. When stone or water is detected but biome has not yet been calculated.
-			if ((c == c_stone && (air_above || water_above || !biome)) ||
-					(c == c_water_source && (air_above || !biome))) {
-				biome = biomegen->getBiomeAtIndex(index, y);
-
-				depth_top = biome->depth_top;
-				base_filler = MYMAX(depth_top + biome->depth_filler
-						+ noise_filler_depth->result[index], 0);
-				depth_water_top = biome->depth_water_top;
-
-				// Detect stone type for dungeons during every biome calculation.
-				// This is more efficient than detecting per-node and will not
-				// miss any desert stone or sandstone biomes.
-				if (biome->c_stone == c_desert_stone)
-					stone_type = DESERT_STONE;
-				else if (biome->c_stone == c_sandstone)
-					stone_type = SANDSTONE;
-			}
-
-			if (c == c_stone) {
-				content_t c_below = vm->m_data[vi - em.X].getContent();
-
-				// If the node below isn't solid, make this node stone, so that
-				// any top/filler nodes above are structurally supported.
-				// This is done by aborting the cycle of top/filler placement
-				// immediately by forcing nplaced to stone level.
-				if (c_below == CONTENT_AIR || c_below == c_water_source)
-					nplaced = U16_MAX;
-
-				if (nplaced < depth_top) {
-					vm->m_data[vi] = MapNode(biome->c_top);
-					nplaced++;
-				} else if (nplaced < base_filler) {
-					vm->m_data[vi] = MapNode(biome->c_filler);
-					nplaced++;
-				} else {
-					vm->m_data[vi] = MapNode(biome->c_stone);
-				}
-
-				air_above = false;
-				water_above = false;
-			} else if (c == c_water_source) {
-				vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top)) ?
-						biome->c_water_top : biome->c_water);
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = false;
-				water_above = true;
-			} else if (c == CONTENT_AIR) {
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = true;
-				water_above = false;
-			} else {  // Possible various nodes overgenerated from neighbouring mapchunks
-				nplaced = U16_MAX;  // Disable top/filler placement
-				air_above = false;
-				water_above = false;
-			}
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-	}
-
-	return stone_type;
-}
-
-
-void MapgenV7::dustTopNodes()
-{
-	if (node_max.Y < water_level)
-		return;
-
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
-
-		if (biome->c_dust == CONTENT_IGNORE)
-			continue;
-
-		u32 vi = vm->m_area.index(x, full_node_max.Y, z);
-		content_t c_full_max = vm->m_data[vi].getContent();
-		s16 y_start;
-
-		if (c_full_max == CONTENT_AIR) {
-			y_start = full_node_max.Y - 1;
-		} else if (c_full_max == CONTENT_IGNORE) {
-			vi = vm->m_area.index(x, node_max.Y + 1, z);
-			content_t c_max = vm->m_data[vi].getContent();
-
-			if (c_max == CONTENT_AIR)
-				y_start = node_max.Y;
-			else
-				continue;
-		} else {
-			continue;
-		}
-
-		vi = vm->m_area.index(x, y_start, z);
-		for (s16 y = y_start; y >= node_min.Y - 1; y--) {
-			if (vm->m_data[vi].getContent() != CONTENT_AIR)
-				break;
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-
-		content_t c = vm->m_data[vi].getContent();
-		if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
-			vm->m_area.add_y(em, vi, 1);
-			vm->m_data[vi] = MapNode(biome->c_dust);
-		}
-	}
-}
-
-
-void MapgenV7::generateCaves(s16 max_stone_y)
-{
-	if (max_stone_y < node_min.Y)
-		return;
-
-	noise_cave1->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
-	noise_cave2->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
-
-	v3s16 em = vm->m_area.getExtent();
-	u32 index2d = 0;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
-		bool column_is_open = false;  // Is column open to overground
-		bool is_tunnel = false;  // Is tunnel or tunnel floor
-		// Indexes at column top (node_max.Y)
-		u32 vi = vm->m_area.index(x, node_max.Y, z);
-		u32 index3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride +
-			(x - node_min.X);
-		// Biome of column
-		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
-
-		// Don't excavate the overgenerated stone at node_max.Y + 1,
-		// this creates a 'roof' over the tunnel, preventing light in
-		// tunnels at mapchunk borders when generating mapchunks upwards.
-		// This 'roof' is removed when the mapchunk above is generated.
-		for (s16 y = node_max.Y; y >= node_min.Y - 1; y--,
-				index3d -= ystride,
-				vm->m_area.add_y(em, vi, -1)) {
-
-			content_t c = vm->m_data[vi].getContent();
-			if (c == CONTENT_AIR || c == biome->c_water_top ||
-					c == biome->c_water) {
-				column_is_open = true;
-				continue;
-			}
-			// Ground
-			float d1 = contour(noise_cave1->result[index3d]);
-			float d2 = contour(noise_cave2->result[index3d]);
-
-			if (d1 * d2 > cave_width && ndef->get(c).is_ground_content) {
-				// In tunnel and ground content, excavate
-				vm->m_data[vi] = MapNode(CONTENT_AIR);
-				is_tunnel = true;
-			} else {
-				// Not in tunnel or not ground content
-				if (is_tunnel && column_is_open &&
-						(c == biome->c_filler || c == biome->c_stone))
-					// Tunnel entrance floor
-					vm->m_data[vi] = MapNode(biome->c_top);
-
-				column_is_open = false;
-				is_tunnel = false;
-			}
-		}
-	}
-
-	if (node_min.Y >= water_level)
-		return;
-
-	PseudoRandom ps(blockseed + 21343);
-	u32 bruises_count = ps.range(0, 2);
-	for (u32 i = 0; i < bruises_count; i++) {
-		CaveV7 cave(this, &ps);
-		cave.makeCave(node_min, node_max, max_stone_y);
-	}
-}
-
-
-///////////////////////////////////////////////////////////////
-
+////////////////////////////////////////////////////////////////////////////////
+//// Code Boneyard
+////
+//// Much of the stuff here has potential to become useful again at some point
+//// in the future, but we don't want it to get lost or forgotten in version
+//// control.
+////
 
 #if 0
 int MapgenV7::generateMountainTerrain(s16 ymax)
diff --git a/src/mapgen_v7.h b/src/mapgen_v7.h
index a8dd9986d..21beab2b4 100644
--- a/src/mapgen_v7.h
+++ b/src/mapgen_v7.h
@@ -54,42 +54,24 @@ struct MapgenV7Params : public MapgenSpecificParams {
 	void writeParams(Settings *settings) const;
 };
 
-class MapgenV7 : public Mapgen {
+class MapgenV7 : public MapgenBasic {
 public:
-	EmergeManager *m_emerge;
-	BiomeManager *bmgr;
-
-	int ystride;
 	int zstride_1u1d;
-	int zstride_1d;
-
-	v3s16 node_min;
-	v3s16 node_max;
-	v3s16 full_node_min;
-	v3s16 full_node_max;
 
 	s16 *ridge_heightmap;
 
 	u32 spflags;
-	float cave_width;
 	Noise *noise_terrain_base;
 	Noise *noise_terrain_alt;
 	Noise *noise_terrain_persist;
 	Noise *noise_height_select;
-	Noise *noise_filler_depth;
 	Noise *noise_mount_height;
 	Noise *noise_ridge_uwater;
 	Noise *noise_mountain;
 	Noise *noise_ridge;
-	Noise *noise_cave1;
-	Noise *noise_cave2;
 
-	content_t c_stone;
-	content_t c_water_source;
 	content_t c_lava_source;
-	content_t c_desert_stone;
 	content_t c_ice;
-	content_t c_sandstone;
 
 	content_t c_cobble;
 	content_t c_stair_cobble;
@@ -112,11 +94,6 @@ public:
 
 	int generateTerrain();
 	void generateRidgeTerrain();
-
-	MgStoneType generateBiomes();
-	void dustTopNodes();
-
-	void generateCaves(s16 max_stone_y);
 };
 
 struct MapgenFactoryV7 : public MapgenFactory {
diff --git a/src/mapgen_valleys.cpp b/src/mapgen_valleys.cpp
index 44083d9d3..fa790677a 100644
--- a/src/mapgen_valleys.cpp
+++ b/src/mapgen_valleys.cpp
@@ -65,7 +65,7 @@ static FlagDesc flagdesc_mapgen_valleys[] = {
 
 
 MapgenValleys::MapgenValleys(int mapgenid, MapgenParams *params, EmergeManager *emerge)
-	: Mapgen(mapgenid, params, emerge)
+	: MapgenBasic(mapgenid, params, emerge)
 {
 	this->m_emerge = emerge;
 	this->bmgr     = emerge->biomemgr;
@@ -302,7 +302,7 @@ void MapgenValleys::makeChunk(BlockMakeData *data)
 
 	// Cave creation.
 	if (flags & MG_CAVES)
-		generateCaves(stone_surface_max_y);
+		generateCaves(stone_surface_max_y, large_cave_depth);
 
 	// Dungeon creation
 	if ((flags & MG_DUNGEONS) && node_max.Y < 50 && (stone_surface_max_y >= node_min.Y)) {
@@ -692,166 +692,7 @@ int MapgenValleys::generateTerrain()
 	return surface_max_y;
 }
 
-
-MgStoneType MapgenValleys::generateBiomes()
-{
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-	MgStoneType stone_type = STONE;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = NULL;
-		u16 depth_top = 0;
-		u16 base_filler = 0;
-		u16 depth_water_top = 0;
-		u32 vi = vm->m_area.index(x, node_max.Y, z);
-
-		// Check node at base of mapchunk above, either a node of a previously
-		// generated mapchunk or if not, a node of overgenerated base terrain.
-		content_t c_above = vm->m_data[vi + em.X].getContent();
-		bool air_above = c_above == CONTENT_AIR;
-		bool water_above = (c_above == c_water_source || c_above == c_river_water_source);
-
-		// If there is air or water above enable top/filler placement, otherwise force
-		// nplaced to stone level by setting a number exceeding any possible filler depth.
-		u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
-
-		for (s16 y = node_max.Y; y >= node_min.Y; y--) {
-			content_t c = vm->m_data[vi].getContent();
-
-			// Biome is recalculated each time an upper surface is detected while
-			// working down a column. The selected biome then remains in effect for
-			// all nodes below until the next surface and biome recalculation.
-			// Biome is recalculated:
-			// 1. At the surface of stone below air or water.
-			// 2. At the surface of water below air.
-			// 3. When stone or water is detected but biome has not yet been calculated.
-			if ((c == c_stone && (air_above || water_above || !biome))
-					|| ((c == c_water_source || c == c_river_water_source)
-						&& (air_above || !biome))) {
-				// Both heat and humidity have already been adjusted for altitude.
-				biome = biomegen->getBiomeAtIndex(index, y);
-
-				depth_top = biome->depth_top;
-				base_filler = MYMAX(depth_top
-						+ biome->depth_filler
-						+ noise_filler_depth->result[index], 0.f);
-				depth_water_top = biome->depth_water_top;
-
-				// Detect stone type for dungeons during every biome calculation.
-				// This is more efficient than detecting per-node and will not
-				// miss any desert stone or sandstone biomes.
-				if (biome->c_stone == c_desert_stone)
-					stone_type = DESERT_STONE;
-				else if (biome->c_stone == c_sandstone)
-					stone_type = SANDSTONE;
-			}
-
-			if (c == c_stone) {
-				content_t c_below = vm->m_data[vi - em.X].getContent();
-
-				// If the node below isn't solid, make this node stone, so that
-				// any top/filler nodes above are structurally supported.
-				// This is done by aborting the cycle of top/filler placement
-				// immediately by forcing nplaced to stone level.
-				if (c_below == CONTENT_AIR
-						|| c_below == c_water_source
-						|| c_below == c_river_water_source)
-					nplaced = U16_MAX;
-
-				if (nplaced < depth_top) {
-					vm->m_data[vi] = MapNode(biome->c_top);
-					nplaced++;
-				} else if (nplaced < base_filler) {
-					vm->m_data[vi] = MapNode(biome->c_filler);
-					nplaced++;
-				} else {
-					vm->m_data[vi] = MapNode(biome->c_stone);
-				}
-
-				air_above = false;
-				water_above = false;
-			} else if (c == c_water_source) {
-				vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top))
-						? biome->c_water_top : biome->c_water);
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = false;
-				water_above = true;
-			} else if (c == c_river_water_source) {
-				vm->m_data[vi] = MapNode(biome->c_river_water);
-				nplaced = depth_top;  // Enable filler placement for next surface
-				air_above = false;
-				water_above = true;
-			} else if (c == CONTENT_AIR) {
-				nplaced = 0;  // Enable top/filler placement for next surface
-				air_above = true;
-				water_above = false;
-			} else {  // Possible various nodes overgenerated from neighbouring mapchunks
-				nplaced = U16_MAX;  // Disable top/filler placement
-				air_above = false;
-				water_above = false;
-			}
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-	}
-
-	return stone_type;
-}
-
-
-void MapgenValleys::dustTopNodes()
-{
-	if (node_max.Y < water_level)
-		return;
-
-	v3s16 em = vm->m_area.getExtent();
-	u32 index = 0;
-
-	for (s16 z = node_min.Z; z <= node_max.Z; z++)
-	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
-		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
-
-		if (biome->c_dust == CONTENT_IGNORE)
-			continue;
-
-		u32 vi = vm->m_area.index(x, full_node_max.Y, z);
-		content_t c_full_max = vm->m_data[vi].getContent();
-		s16 y_start;
-
-		if (c_full_max == CONTENT_AIR) {
-			y_start = full_node_max.Y - 1;
-		} else if (c_full_max == CONTENT_IGNORE) {
-			vi = vm->m_area.index(x, node_max.Y + 1, z);
-			content_t c_max = vm->m_data[vi].getContent();
-
-			if (c_max == CONTENT_AIR)
-				y_start = node_max.Y;
-			else
-				continue;
-		} else {
-			continue;
-		}
-
-		vi = vm->m_area.index(x, y_start, z);
-		for (s16 y = y_start; y >= node_min.Y - 1; y--) {
-			if (vm->m_data[vi].getContent() != CONTENT_AIR)
-				break;
-
-			vm->m_area.add_y(em, vi, -1);
-		}
-
-		content_t c = vm->m_data[vi].getContent();
-		if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
-			vm->m_area.add_y(em, vi, 1);
-			vm->m_data[vi] = MapNode(biome->c_dust);
-		}
-	}
-}
-
-
-void MapgenValleys::generateCaves(s16 max_stone_y)
+void MapgenValleys::generateCaves(s16 max_stone_y, s16 large_cave_depth)
 {
 	if (max_stone_y < node_min.Y)
 		return;
diff --git a/src/mapgen_valleys.h b/src/mapgen_valleys.h
index 0e268c1cf..2ab253430 100644
--- a/src/mapgen_valleys.h
+++ b/src/mapgen_valleys.h
@@ -85,7 +85,7 @@ struct TerrainNoise {
 	float inter_valley_fill;
 };
 
-class MapgenValleys : public Mapgen {
+class MapgenValleys : public MapgenBasic {
 public:
 
 	MapgenValleys(int mapgenid, MapgenParams *params, EmergeManager *emerge);
@@ -97,13 +97,9 @@ public:
 	s16 large_cave_depth;
 
 private:
-	EmergeManager *m_emerge;
-	BiomeManager *bmgr;
 	BiomeGenOriginal *m_bgen;
 
-	int ystride;
 	int zstride;
-	int zstride_1d;
 
 	float map_gen_limit;
 
@@ -113,11 +109,6 @@ private:
 	s16 cave_water_max_height;
 	s16 lava_max_height;
 
-	v3s16 node_min;
-	v3s16 node_max;
-	v3s16 full_node_min;
-	v3s16 full_node_max;
-
 	u32 spflags;
 	float altitude_chill;
 	s16 lava_features_lim;
@@ -126,10 +117,6 @@ private:
 	float river_size_factor;
 	float *tcave_cache;
 	s16 water_features_lim;
-	float cave_width;
-	Noise *noise_filler_depth;
-	Noise *noise_cave1;
-	Noise *noise_cave2;
 	Noise *noise_inter_valley_fill;
 	Noise *noise_inter_valley_slope;
 	Noise *noise_rivers;
@@ -139,19 +126,13 @@ private:
 	Noise *noise_valley_profile;
 
 	content_t c_cobble;
-	content_t c_desert_stone;
 	content_t c_dirt;
-	content_t c_ice;
 	content_t c_lava_source;
 	content_t c_mossycobble;
-	content_t c_river_water_source;
 	content_t c_sand;
-	content_t c_sandstone;
 	content_t c_sandstonebrick;
 	content_t c_stair_cobble;
 	content_t c_stair_sandstonebrick;
-	content_t c_stone;
-	content_t c_water_source;
 
 	float terrainLevelAtPoint(s16 x, s16 z);
 
@@ -161,10 +142,7 @@ private:
 	float terrainLevelFromNoise(TerrainNoise *tn);
 	float adjustedTerrainLevelFromNoise(TerrainNoise *tn);
 
-	MgStoneType generateBiomes();
-	void dustTopNodes();
-
-	void generateCaves(s16 max_stone_y);
+	virtual void generateCaves(s16 max_stone_y, s16 large_cave_depth);
 };
 
 struct MapgenFactoryValleys : public MapgenFactory {