Mapgen: Add 4D fractal mapgen

4 files changed, 733 insertions, 0 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 32e25c3bd..72b52436c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -352,6 +352,7 @@ set(common_SRCS
 	map.cpp
 	mapblock.cpp
 	mapgen.cpp
+	mapgen_fractal.cpp
 	mapgen_singlenode.cpp
 	mapgen_v5.cpp
 	mapgen_v6.cpp
diff --git a/src/emerge.cpp b/src/emerge.cpp
index 92edd2007..3532ca29d 100644
--- a/src/emerge.cpp
+++ b/src/emerge.cpp
@@ -34,6 +34,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "log.h"
 #include "map.h"
 #include "mapblock.h"
+#include "mapgen_fractal.h"
 #include "mapgen_v5.h"
 #include "mapgen_v6.h"
 #include "mapgen_v7.h"
@@ -104,6 +105,7 @@ MapgenDesc g_reg_mapgens[] = {
 	{"v5",         new MapgenFactoryV5,         true},
 	{"v6",         new MapgenFactoryV6,         true},
 	{"v7",         new MapgenFactoryV7,         true},
+	{"fractal",    new MapgenFactoryFractal,    false},
 	{"singlenode", new MapgenFactorySinglenode, false},
 };
 
diff --git a/src/mapgen_fractal.cpp b/src/mapgen_fractal.cpp
new file mode 100644
index 000000000..144fa29b2
--- /dev/null
+++ b/src/mapgen_fractal.cpp
@@ -0,0 +1,597 @@
+/*
+Minetest
+Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
+Additional development and fractal code by paramat
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+
+#include "mapgen.h"
+#include "voxel.h"
+#include "noise.h"
+#include "mapblock.h"
+#include "mapnode.h"
+#include "map.h"
+#include "content_sao.h"
+#include "nodedef.h"
+#include "voxelalgorithms.h"
+#include "settings.h" // For g_settings
+#include "emerge.h"
+#include "dungeongen.h"
+#include "cavegen.h"
+#include "treegen.h"
+#include "mg_biome.h"
+#include "mg_ore.h"
+#include "mg_decoration.h"
+#include "mapgen_fractal.h"
+
+
+FlagDesc flagdesc_mapgen_fractal[] = {
+	{"julia", MGFRACTAL_JULIA},
+	{NULL,    0}
+};
+
+///////////////////////////////////////////////////////////////////////////////////////
+
+
+MapgenFractal::MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *emerge)
+	: Mapgen(mapgenid, params, emerge)
+{
+	this->m_emerge = emerge;
+	this->bmgr     = emerge->biomemgr;
+
+	//// amount of elements to skip for the next index
+	//// for noise/height/biome maps (not vmanip)
+	this->ystride = csize.X;
+	this->zstride = csize.X * (csize.Y + 2);
+
+	this->biomemap        = new u8[csize.X * csize.Z];
+	this->heightmap       = new s16[csize.X * csize.Z];
+	this->heatmap         = NULL;
+	this->humidmap        = NULL;
+
+	MapgenFractalParams *sp = (MapgenFractalParams *)params->sparams;
+	this->spflags = sp->spflags;
+	this->iterations = sp->iterations;
+	this->scale_x = sp->scale_x;
+	this->scale_y = sp->scale_y;
+	this->scale_z = sp->scale_z;
+	this->offset_x = sp->offset_x;
+	this->offset_y = sp->offset_y;
+	this->offset_z = sp->offset_z;
+
+	//// 3d terrain noise
+	noise_cave1    = new Noise(&sp->np_cave1,    seed, csize.X, csize.Y + 2, csize.Z);
+	noise_cave2    = new Noise(&sp->np_cave2,    seed, csize.X, csize.Y + 2, csize.Z);
+
+	//// Biome noise
+	noise_heat           = new Noise(&params->np_biome_heat,           seed, csize.X, csize.Z);
+	noise_humidity       = new Noise(&params->np_biome_humidity,       seed, csize.X, csize.Z);
+	noise_heat_blend     = new Noise(&params->np_biome_heat_blend,     seed, csize.X, csize.Z);
+	noise_humidity_blend = new Noise(&params->np_biome_humidity_blend, seed, csize.X, csize.Z);
+
+	//// Resolve nodes to be used
+	INodeDefManager *ndef = emerge->ndef;
+
+	c_stone                = ndef->getId("mapgen_stone");
+	c_water_source         = ndef->getId("mapgen_water_source");
+	c_lava_source          = ndef->getId("mapgen_lava_source");
+	c_desert_stone         = ndef->getId("mapgen_desert_stone");
+	c_ice                  = ndef->getId("mapgen_ice");
+	c_sandstone            = ndef->getId("mapgen_sandstone");
+
+	c_cobble               = ndef->getId("mapgen_cobble");
+	c_stair_cobble         = ndef->getId("mapgen_stair_cobble");
+	c_mossycobble          = ndef->getId("mapgen_mossycobble");
+	c_sandstonebrick       = ndef->getId("mapgen_sandstonebrick");
+	c_stair_sandstonebrick = ndef->getId("mapgen_stair_sandstonebrick");
+
+	if (c_ice == CONTENT_IGNORE)
+		c_ice = CONTENT_AIR;
+	if (c_mossycobble == CONTENT_IGNORE)
+		c_mossycobble = c_cobble;
+	if (c_stair_cobble == CONTENT_IGNORE)
+		c_stair_cobble = c_cobble;
+	if (c_sandstonebrick == CONTENT_IGNORE)
+		c_sandstonebrick = c_sandstone;
+	if (c_stair_sandstonebrick == CONTENT_IGNORE)
+		c_stair_sandstonebrick = c_sandstone;
+}
+
+
+MapgenFractal::~MapgenFractal()
+{
+	delete noise_cave1;
+	delete noise_cave2;
+
+	delete noise_heat;
+	delete noise_humidity;
+	delete noise_heat_blend;
+	delete noise_humidity_blend;
+
+	delete[] heightmap;
+	delete[] biomemap;
+}
+
+
+MapgenFractalParams::MapgenFractalParams()
+{
+	spflags = 0;
+
+	iterations = 9;
+	scale_x = 1024;
+	scale_y = 256;
+	scale_z = 1024;
+	offset_x = -1.75;
+	offset_y = 0;
+	offset_z = 0;
+	slice_w = 0.5;
+	julia_x = 0.33;
+	julia_y = 0.33;
+	julia_z = 0.33;
+	julia_w = 0.33;
+
+	np_cave1 = NoiseParams(0, 12, v3f(128, 128, 128), 52534, 4, 0.5, 2.0);
+	np_cave2 = NoiseParams(0, 12, v3f(128, 128, 128), 10325, 4, 0.5, 2.0);
+}
+
+
+void MapgenFractalParams::readParams(const Settings *settings)
+{
+	settings->getFlagStrNoEx("mgfractal_spflags", spflags, flagdesc_mapgen_fractal);
+
+	settings->getU16NoEx("mgfractal_iterations", iterations);
+	settings->getFloatNoEx("mgfractal_scale_x", scale_x);
+	settings->getFloatNoEx("mgfractal_scale_y", scale_y);
+	settings->getFloatNoEx("mgfractal_scale_z", scale_z);
+	settings->getFloatNoEx("mgfractal_offset_x", offset_x);
+	settings->getFloatNoEx("mgfractal_offset_y", offset_y);
+	settings->getFloatNoEx("mgfractal_offset_z", offset_z);
+	settings->getFloatNoEx("mgfractal_slice_w", slice_w);
+	settings->getFloatNoEx("mgfractal_julia_x", julia_x);
+	settings->getFloatNoEx("mgfractal_julia_y", julia_y);
+	settings->getFloatNoEx("mgfractal_julia_z", julia_z);
+	settings->getFloatNoEx("mgfractal_julia_w", julia_w);
+
+	settings->getNoiseParams("mgfractal_np_cave1", np_cave1);
+	settings->getNoiseParams("mgfractal_np_cave2", np_cave2);
+}
+
+
+void MapgenFractalParams::writeParams(Settings *settings) const
+{
+	settings->setFlagStr("mgfractal_spflags", spflags, flagdesc_mapgen_fractal, U32_MAX);
+
+	settings->setU16("mgfractal_iterations", iterations);
+	settings->setFloat("mgfractal_scale_x", scale_x);
+	settings->setFloat("mgfractal_scale_y", scale_y);
+	settings->setFloat("mgfractal_scale_z", scale_z);
+	settings->setFloat("mgfractal_offset_x", offset_x);
+	settings->setFloat("mgfractal_offset_y", offset_y);
+	settings->setFloat("mgfractal_offset_z", offset_z);
+	settings->setFloat("mgfractal_slice_w", slice_w);
+	settings->setFloat("mgfractal_julia_x", julia_x);
+	settings->setFloat("mgfractal_julia_y", julia_y);
+	settings->setFloat("mgfractal_julia_z", julia_z);
+	settings->setFloat("mgfractal_julia_w", julia_w);
+
+	settings->setNoiseParams("mgfractal_np_cave1", np_cave1);
+	settings->setNoiseParams("mgfractal_np_cave2", np_cave2);
+}
+
+
+/////////////////////////////////////////////////////////////////
+
+
+int MapgenFractal::getGroundLevelAtPoint(v2s16 p)
+{
+	s16 search_top = water_level + 128;
+	s16 search_base = water_level;
+	s16 level = -MAX_MAP_GENERATION_LIMIT;
+	for (s16 y = search_top; y >= search_base; y--) {
+		if (getTerrainAtPoint(p.X, y, p.Y))
+			return y;
+	}
+
+	return level;
+}
+
+
+void MapgenFractal::makeChunk(BlockMakeData *data)
+{
+	// Pre-conditions
+	assert(data->vmanip);
+	assert(data->nodedef);
+	assert(data->blockpos_requested.X >= data->blockpos_min.X &&
+		data->blockpos_requested.Y >= data->blockpos_min.Y &&
+		data->blockpos_requested.Z >= data->blockpos_min.Z);
+	assert(data->blockpos_requested.X <= data->blockpos_max.X &&
+		data->blockpos_requested.Y <= data->blockpos_max.Y &&
+		data->blockpos_requested.Z <= data->blockpos_max.Z);
+
+	this->generating = true;
+	this->vm   = data->vmanip;
+	this->ndef = data->nodedef;
+	//TimeTaker t("makeChunk");
+
+	v3s16 blockpos_min = data->blockpos_min;
+	v3s16 blockpos_max = data->blockpos_max;
+	node_min = blockpos_min * MAP_BLOCKSIZE;
+	node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
+	full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
+	full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
+
+	blockseed = getBlockSeed2(full_node_min, seed);
+
+	// Make some noise
+	calculateNoise();
+
+	// Generate base terrain, mountains, and ridges with initial heightmaps
+	s16 stone_surface_max_y = generateTerrain();
+
+	// Create heightmap
+	updateHeightmap(node_min, node_max);
+
+	// Create biomemap at heightmap surface
+	bmgr->calcBiomes(csize.X, csize.Z, noise_heat->result,
+		noise_humidity->result, heightmap, biomemap);
+
+	// Actually place the biome-specific nodes
+	MgStoneType stone_type = generateBiomes(noise_heat->result, noise_humidity->result);
+
+	if (flags & MG_CAVES)
+		generateCaves(stone_surface_max_y);
+
+	if ((flags & MG_DUNGEONS) && (stone_surface_max_y >= node_min.Y)) {
+		DungeonParams dp;
+
+		dp.np_rarity  = nparams_dungeon_rarity;
+		dp.np_density = nparams_dungeon_density;
+		dp.np_wetness = nparams_dungeon_wetness;
+		dp.c_water    = c_water_source;
+		if (stone_type == STONE) {
+			dp.c_cobble = c_cobble;
+			dp.c_moss   = c_mossycobble;
+			dp.c_stair  = c_stair_cobble;
+
+			dp.diagonal_dirs = false;
+			dp.mossratio     = 3.0;
+			dp.holesize      = v3s16(1, 2, 1);
+			dp.roomsize      = v3s16(0, 0, 0);
+			dp.notifytype    = GENNOTIFY_DUNGEON;
+		} else if (stone_type == DESERT_STONE) {
+			dp.c_cobble = c_desert_stone;
+			dp.c_moss   = c_desert_stone;
+			dp.c_stair  = c_desert_stone;
+
+			dp.diagonal_dirs = true;
+			dp.mossratio     = 0.0;
+			dp.holesize      = v3s16(2, 3, 2);
+			dp.roomsize      = v3s16(2, 5, 2);
+			dp.notifytype    = GENNOTIFY_TEMPLE;
+		} else if (stone_type == SANDSTONE) {
+			dp.c_cobble = c_sandstonebrick;
+			dp.c_moss   = c_sandstonebrick;
+			dp.c_stair  = c_sandstonebrick;
+
+			dp.diagonal_dirs = false;
+			dp.mossratio     = 0.0;
+			dp.holesize      = v3s16(2, 2, 2);
+			dp.roomsize      = v3s16(2, 0, 2);
+			dp.notifytype    = GENNOTIFY_DUNGEON;
+		}
+
+		DungeonGen dgen(this, &dp);
+		dgen.generate(blockseed, full_node_min, full_node_max);
+	}
+
+	// Generate the registered decorations
+	m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);
+
+	// Generate the registered ores
+	m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);
+
+	// Sprinkle some dust on top after everything else was generated
+	dustTopNodes();
+
+	//printf("makeChunk: %dms\n", t.stop());
+
+	updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
+
+	if (flags & MG_LIGHT)
+		calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
+			full_node_min, full_node_max);
+
+	//setLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
+	//			node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE, 0xFF);
+
+	this->generating = false;
+}
+
+
+void MapgenFractal::calculateNoise()
+{
+	//TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
+	int x = node_min.X;
+	int y = node_min.Y - 1;
+	int z = node_min.Z;
+
+	if (flags & MG_CAVES) {
+		noise_cave1->perlinMap3D(x, y, z);
+		noise_cave2->perlinMap3D(x, y, z);
+	}
+
+	noise_heat->perlinMap2D(x, z);
+	noise_humidity->perlinMap2D(x, z);
+	noise_heat_blend->perlinMap2D(x, z);
+	noise_humidity_blend->perlinMap2D(x, z);
+
+	for (s32 i = 0; i < csize.X * csize.Z; i++) {
+		noise_heat->result[i] += noise_heat_blend->result[i];
+		noise_humidity->result[i] += noise_humidity_blend->result[i];
+	}
+
+	heatmap = noise_heat->result;
+	humidmap = noise_humidity->result;
+	//printf("calculateNoise: %dus\n", t.stop());
+}
+
+
+bool MapgenFractal::getTerrainAtPoint(s16 x, s16 y, s16 z)
+{
+	float cx, cy, cz, cw, ox, oy, oz, ow;
+
+	if (spflags & MGFRACTAL_JULIA) {  // Julia set
+		cx = julia_x;
+		cy = julia_y;
+		cz = julia_z;
+		cw = julia_w;
+		ox = (float)x / scale_x + offset_x;
+		oy = (float)y / scale_y + offset_y;
+		oz = (float)z / scale_z + offset_z;
+		ow = slice_w;
+	} else {  // Mandelbrot set
+		cx = (float)x / scale_x + offset_x;
+		cy = (float)y / scale_y + offset_y;
+		cz = (float)z / scale_z + offset_z;
+		cw = slice_w;
+		ox = 0.0;
+		oy = 0.0;
+		oz = 0.0;
+		ow = 0.0;
+	}
+
+	for (u16 iter = 0; iter < iterations; iter++) {
+		// 4D "Roundy" Mandelbrot set
+		float nx = ox * ox - oy * oy - oz * oz - ow * ow + cx;
+		float ny = 2.0 * (ox * oy + oz * ow) + cy;
+		float nz = 2.0 * (ox * oz + oy * ow) + cz;
+		float nw = 2.0 * (ox * ow + oy * oz) + cw;
+
+		if (nx * nx + ny * ny + nz * nz + nw * nw > 4.0) {
+			return false;
+		}
+
+		ox = nx;
+		oy = ny;
+		oz = nz;
+		ow = nw;
+	}
+
+	return true;
+}
+
+
+s16 MapgenFractal::generateTerrain()
+{
+	MapNode n_air(CONTENT_AIR);
+	MapNode n_stone(c_stone);
+	MapNode n_water(c_water_source);
+
+	s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
+
+	for (s16 z = node_min.Z; z <= node_max.Z; z++)
+	for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
+		u32 i = vm->m_area.index(node_min.X, y, z);
+		for (s16 x = node_min.X; x <= node_max.X; x++, i++) {
+			if (vm->m_data[i].getContent() == CONTENT_IGNORE) {
+				if (getTerrainAtPoint(x, y, z)) {
+					vm->m_data[i] = n_stone;
+					if (y > stone_surface_max_y)
+						stone_surface_max_y = y;
+				} else if (y <= water_level) {
+					vm->m_data[i] = n_water;
+				} else {
+					vm->m_data[i] = n_air;
+				}
+			}
+		}
+	}
+
+	return stone_surface_max_y;
+}
+
+
+MgStoneType MapgenFractal::generateBiomes(float *heat_map, float *humidity_map)
+{
+	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 = bmgr->getBiome(heat_map[index], humidity_map[index], y);
+				depth_top = biome->depth_top;
+				base_filler = depth_top + biome->depth_filler;
+				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) {
+		u32 index   = 0;
+
+		for (s16 z = node_min.Z; z <= node_max.Z; z++)
+		for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
+			u32 i = vm->m_area.index(node_min.X, y, z);
+			for (s16 x = node_min.X; x <= node_max.X; x++, i++, index++) {
+				float d1 = contour(noise_cave1->result[index]);
+				float d2 = contour(noise_cave2->result[index]);
+				if (d1 * d2 > 0.3) {
+					content_t c = vm->m_data[i].getContent();
+					if (!ndef->get(c).is_ground_content || c == CONTENT_AIR)
+						continue;
+
+					vm->m_data[i] = MapNode(CONTENT_AIR);
+				}
+			}
+		}
+	}
+}
+
diff --git a/src/mapgen_fractal.h b/src/mapgen_fractal.h
new file mode 100644
index 000000000..71729cbed
--- /dev/null
+++ b/src/mapgen_fractal.h
@@ -0,0 +1,133 @@
+/*
+Minetest
+Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
+Additional development and fractal code by paramat
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#ifndef MAPGEN_FRACTAL_HEADER
+#define MAPGEN_FRACTAL_HEADER
+
+#include "mapgen.h"
+
+/////////////////// Mapgen Fractal flags
+#define MGFRACTAL_JULIA 0x01
+
+class BiomeManager;
+
+extern FlagDesc flagdesc_mapgen_fractal[];
+
+
+struct MapgenFractalParams : public MapgenSpecificParams {
+	u32 spflags;
+
+	u16 iterations;
+	float scale_x;
+	float scale_y;
+	float scale_z;
+	float offset_x;
+	float offset_y;
+	float offset_z;
+	float slice_w;
+	float julia_x;
+	float julia_y;
+	float julia_z;
+	float julia_w;
+
+	NoiseParams np_cave1;
+	NoiseParams np_cave2;
+
+	MapgenFractalParams();
+	~MapgenFractalParams() {}
+
+	void readParams(const Settings *settings);
+	void writeParams(Settings *settings) const;
+};
+
+class MapgenFractal : public Mapgen {
+public:
+	EmergeManager *m_emerge;
+	BiomeManager *bmgr;
+
+	int ystride;
+	int zstride;
+	u32 spflags;
+
+	v3s16 node_min;
+	v3s16 node_max;
+	v3s16 full_node_min;
+	v3s16 full_node_max;
+
+	u16 iterations;
+	float scale_x;
+	float scale_y;
+	float scale_z;
+	float offset_x;
+	float offset_y;
+	float offset_z;
+	float slice_w;
+	float julia_x;
+	float julia_y;
+	float julia_z;
+	float julia_w;
+
+	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;
+	content_t c_mossycobble;
+	content_t c_sandstonebrick;
+	content_t c_stair_sandstonebrick;
+
+	MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *emerge);
+	~MapgenFractal();
+
+	virtual void makeChunk(BlockMakeData *data);
+	int getGroundLevelAtPoint(v2s16 p);
+	void calculateNoise();
+	bool getTerrainAtPoint(s16 x, s16 y, s16 z);
+	s16 generateTerrain();
+	MgStoneType generateBiomes(float *heat_map, float *humidity_map);
+	void dustTopNodes();
+	void generateCaves(s16 max_stone_y);
+};
+
+struct MapgenFactoryFractal : public MapgenFactory {
+	Mapgen *createMapgen(int mgid, MapgenParams *params, EmergeManager *emerge)
+	{
+		return new MapgenFractal(mgid, params, emerge);
+	};
+
+	MapgenSpecificParams *createMapgenParams()
+	{
+		return new MapgenFractalParams();
+	};
+};
+
+#endif