Move files to subdirectories (#6599)

* Move files around

1 files changed, 743 insertions, 0 deletions

diff --git a/src/mapgen/mapgen_valleys.cpp b/src/mapgen/mapgen_valleys.cpp
new file mode 100644
index 000000000..a13bb4582
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+++ b/src/mapgen/mapgen_valleys.cpp
@@ -0,0 +1,743 @@
+/*
+Minetest Valleys C
+Copyright (C) 2016-2017 Duane Robertson <duane@duanerobertson.com>
+Copyright (C) 2016-2017 paramat
+
+Based on Valleys Mapgen by Gael de Sailly
+ (https://forum.minetest.net/viewtopic.php?f=9&t=11430)
+and mapgen_v7, mapgen_flat by kwolekr and paramat.
+
+Licensing changed by permission of Gael de Sailly.
+
+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 "nodedef.h"
+#include "voxelalgorithms.h"
+#include "settings.h" // For g_settings
+#include "emerge.h"
+#include "dungeongen.h"
+#include "mg_biome.h"
+#include "mg_ore.h"
+#include "mg_decoration.h"
+#include "mapgen_valleys.h"
+#include "cavegen.h"
+
+
+//#undef NDEBUG
+//#include "assert.h"
+
+//#include "util/timetaker.h"
+//#include "profiler.h"
+
+
+//static Profiler mapgen_prof;
+//Profiler *mapgen_profiler = &mapgen_prof;
+
+static FlagDesc flagdesc_mapgen_valleys[] = {
+	{"altitude_chill", MGVALLEYS_ALT_CHILL},
+	{"humid_rivers",   MGVALLEYS_HUMID_RIVERS},
+	{NULL,             0}
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+
+MapgenValleys::MapgenValleys(int mapgenid, MapgenValleysParams *params, EmergeManager *emerge)
+	: MapgenBasic(mapgenid, params, emerge)
+{
+	// NOTE: MapgenValleys has a hard dependency on BiomeGenOriginal
+	m_bgen = (BiomeGenOriginal *)biomegen;
+
+	BiomeParamsOriginal *bp = (BiomeParamsOriginal *)params->bparams;
+
+	spflags            = params->spflags;
+	altitude_chill     = params->altitude_chill;
+	large_cave_depth   = params->large_cave_depth;
+	lava_features_lim  = rangelim(params->lava_features, 0, 10);
+	massive_cave_depth = params->massive_cave_depth;
+	river_depth_bed    = params->river_depth + 1.f;
+	river_size_factor  = params->river_size / 100.f;
+	water_features_lim = rangelim(params->water_features, 0, 10);
+	cave_width         = params->cave_width;
+
+	//// 2D Terrain noise
+	noise_filler_depth       = new Noise(&params->np_filler_depth,       seed, csize.X, csize.Z);
+	noise_inter_valley_slope = new Noise(&params->np_inter_valley_slope, seed, csize.X, csize.Z);
+	noise_rivers             = new Noise(&params->np_rivers,             seed, csize.X, csize.Z);
+	noise_terrain_height     = new Noise(&params->np_terrain_height,     seed, csize.X, csize.Z);
+	noise_valley_depth       = new Noise(&params->np_valley_depth,       seed, csize.X, csize.Z);
+	noise_valley_profile     = new Noise(&params->np_valley_profile,     seed, csize.X, csize.Z);
+
+	//// 3D Terrain noise
+	// 1-up 1-down overgeneration
+	noise_inter_valley_fill = new Noise(&params->np_inter_valley_fill, seed, csize.X, csize.Y + 2, csize.Z);
+	// 1-down overgeneraion
+	noise_cave1             = new Noise(&params->np_cave1,             seed, csize.X, csize.Y + 1, csize.Z);
+	noise_cave2             = new Noise(&params->np_cave2,             seed, csize.X, csize.Y + 1, csize.Z);
+	noise_massive_caves     = new Noise(&params->np_massive_caves,     seed, csize.X, csize.Y + 1, csize.Z);
+
+	humid_rivers       = (spflags & MGVALLEYS_HUMID_RIVERS);
+	use_altitude_chill = (spflags & MGVALLEYS_ALT_CHILL);
+	humidity_adjust    = bp->np_humidity.offset - 50.f;
+
+	// a small chance of overflows if the settings are very high
+	cave_water_max_height = water_level + MYMAX(0, water_features_lim - 4) * 50;
+	lava_max_height       = water_level + MYMAX(0, lava_features_lim - 4) * 50;
+
+	tcave_cache = new float[csize.Y + 2];
+}
+
+
+MapgenValleys::~MapgenValleys()
+{
+	delete noise_cave1;
+	delete noise_cave2;
+	delete noise_filler_depth;
+	delete noise_inter_valley_fill;
+	delete noise_inter_valley_slope;
+	delete noise_rivers;
+	delete noise_massive_caves;
+	delete noise_terrain_height;
+	delete noise_valley_depth;
+	delete noise_valley_profile;
+
+	delete[] tcave_cache;
+}
+
+
+MapgenValleysParams::MapgenValleysParams():
+	np_cave1              (0,     12,   v3f(61,   61,   61),   52534, 3, 0.5,   2.0),
+	np_cave2              (0,     12,   v3f(67,   67,   67),   10325, 3, 0.5,   2.0),
+	np_filler_depth       (0.f,   1.2f, v3f(256,  256,  256),  1605,  3, 0.5f,  2.f),
+	np_inter_valley_fill  (0.f,   1.f,  v3f(256,  512,  256),  1993,  6, 0.8f,  2.f),
+	np_inter_valley_slope (0.5f,  0.5f, v3f(128,  128,  128),  746,   1, 1.f,   2.f),
+	np_rivers             (0.f,   1.f,  v3f(256,  256,  256),  -6050, 5, 0.6f,  2.f),
+	np_massive_caves      (0.f,   1.f,  v3f(768,  256,  768),  59033, 6, 0.63f, 2.f),
+	np_terrain_height     (-10.f, 50.f, v3f(1024, 1024, 1024), 5202,  6, 0.4f,  2.f),
+	np_valley_depth       (5.f,   4.f,  v3f(512,  512,  512),  -1914, 1, 1.f,   2.f),
+	np_valley_profile     (0.6f,  0.5f, v3f(512,  512,  512),  777,   1, 1.f,   2.f)
+{
+}
+
+
+void MapgenValleysParams::readParams(const Settings *settings)
+{
+	settings->getFlagStrNoEx("mgvalleys_spflags",        spflags, flagdesc_mapgen_valleys);
+	settings->getU16NoEx("mgvalleys_altitude_chill",     altitude_chill);
+	settings->getS16NoEx("mgvalleys_large_cave_depth",   large_cave_depth);
+	settings->getU16NoEx("mgvalleys_lava_features",      lava_features);
+	settings->getS16NoEx("mgvalleys_massive_cave_depth", massive_cave_depth);
+	settings->getU16NoEx("mgvalleys_river_depth",        river_depth);
+	settings->getU16NoEx("mgvalleys_river_size",         river_size);
+	settings->getU16NoEx("mgvalleys_water_features",     water_features);
+	settings->getFloatNoEx("mgvalleys_cave_width",       cave_width);
+
+	settings->getNoiseParams("mgvalleys_np_cave1",              np_cave1);
+	settings->getNoiseParams("mgvalleys_np_cave2",              np_cave2);
+	settings->getNoiseParams("mgvalleys_np_filler_depth",       np_filler_depth);
+	settings->getNoiseParams("mgvalleys_np_inter_valley_fill",  np_inter_valley_fill);
+	settings->getNoiseParams("mgvalleys_np_inter_valley_slope", np_inter_valley_slope);
+	settings->getNoiseParams("mgvalleys_np_rivers",             np_rivers);
+	settings->getNoiseParams("mgvalleys_np_massive_caves",      np_massive_caves);
+	settings->getNoiseParams("mgvalleys_np_terrain_height",     np_terrain_height);
+	settings->getNoiseParams("mgvalleys_np_valley_depth",       np_valley_depth);
+	settings->getNoiseParams("mgvalleys_np_valley_profile",     np_valley_profile);
+}
+
+
+void MapgenValleysParams::writeParams(Settings *settings) const
+{
+	settings->setFlagStr("mgvalleys_spflags",        spflags, flagdesc_mapgen_valleys, U32_MAX);
+	settings->setU16("mgvalleys_altitude_chill",     altitude_chill);
+	settings->setS16("mgvalleys_large_cave_depth",   large_cave_depth);
+	settings->setU16("mgvalleys_lava_features",      lava_features);
+	settings->setS16("mgvalleys_massive_cave_depth", massive_cave_depth);
+	settings->setU16("mgvalleys_river_depth",        river_depth);
+	settings->setU16("mgvalleys_river_size",         river_size);
+	settings->setU16("mgvalleys_water_features",     water_features);
+	settings->setFloat("mgvalleys_cave_width",       cave_width);
+
+	settings->setNoiseParams("mgvalleys_np_cave1",              np_cave1);
+	settings->setNoiseParams("mgvalleys_np_cave2",              np_cave2);
+	settings->setNoiseParams("mgvalleys_np_filler_depth",       np_filler_depth);
+	settings->setNoiseParams("mgvalleys_np_inter_valley_fill",  np_inter_valley_fill);
+	settings->setNoiseParams("mgvalleys_np_inter_valley_slope", np_inter_valley_slope);
+	settings->setNoiseParams("mgvalleys_np_rivers",             np_rivers);
+	settings->setNoiseParams("mgvalleys_np_massive_caves",      np_massive_caves);
+	settings->setNoiseParams("mgvalleys_np_terrain_height",     np_terrain_height);
+	settings->setNoiseParams("mgvalleys_np_valley_depth",       np_valley_depth);
+	settings->setNoiseParams("mgvalleys_np_valley_profile",     np_valley_profile);
+}
+
+
+///////////////////////////////////////
+
+
+void MapgenValleys::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);
+
+	// Generate biome noises.  Note this must be executed strictly before
+	// generateTerrain, because generateTerrain depends on intermediate
+	// biome-related noises.
+	m_bgen->calcBiomeNoise(node_min);
+
+	// Generate noise maps and base terrain height.
+	// Modify heat and humidity maps.
+	calculateNoise();
+
+	// Generate base terrain with initial heightmaps
+	s16 stone_surface_max_y = generateTerrain();
+
+	// Recalculate heightmap
+	updateHeightmap(node_min, node_max);
+
+	// Place biome-specific nodes and build biomemap
+	MgStoneType mgstone_type;
+	content_t biome_stone;
+	generateBiomes(&mgstone_type, &biome_stone);
+
+	// Cave creation.
+	if (flags & MG_CAVES)
+		generateCaves(stone_surface_max_y, large_cave_depth);
+
+	// Dungeon creation
+	if ((flags & MG_DUNGEONS) && node_max.Y < 50)
+		generateDungeons(stone_surface_max_y, mgstone_type, biome_stone);
+
+	// Generate the registered decorations
+	if (flags & MG_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();
+
+	//TimeTaker tll("liquid_lighting");
+
+	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);
+
+	//mapgen_profiler->avg("liquid_lighting", tll.stop() / 1000.f);
+	//mapgen_profiler->avg("makeChunk", t.stop() / 1000.f);
+
+	this->generating = false;
+}
+
+
+// Populate the noise tables and do most of the
+// calculation necessary to determine terrain height.
+void MapgenValleys::calculateNoise()
+{
+	//TimeTaker t("calculateNoise", NULL, PRECISION_MICRO);
+
+	int x = node_min.X;
+	int y = node_min.Y - 1;
+	int z = node_min.Z;
+
+	//TimeTaker tcn("actualNoise");
+
+	noise_inter_valley_slope->perlinMap2D(x, z);
+	noise_rivers->perlinMap2D(x, z);
+	noise_terrain_height->perlinMap2D(x, z);
+	noise_valley_depth->perlinMap2D(x, z);
+	noise_valley_profile->perlinMap2D(x, z);
+
+	noise_inter_valley_fill->perlinMap3D(x, y, z);
+
+	//mapgen_profiler->avg("noisemaps", tcn.stop() / 1000.f);
+
+	float heat_offset = 0.f;
+	float humidity_scale = 1.f;
+
+	// Altitude chill tends to reduce the average heat.
+	if (use_altitude_chill)
+		heat_offset = 5.f;
+
+	// River humidity tends to increase the humidity range.
+	if (humid_rivers) {
+		humidity_scale = 0.8f;
+	}
+
+	for (s32 index = 0; index < csize.X * csize.Z; index++) {
+		m_bgen->heatmap[index] += heat_offset;
+		m_bgen->humidmap[index] *= humidity_scale;
+	}
+
+	TerrainNoise tn;
+
+	u32 index = 0;
+	for (tn.z = node_min.Z; tn.z <= node_max.Z; tn.z++)
+	for (tn.x = node_min.X; tn.x <= node_max.X; tn.x++, index++) {
+		// The parameters that we actually need to generate terrain
+		//  are passed by address (and the return value).
+		tn.terrain_height    = noise_terrain_height->result[index];
+		// River noise is replaced with base terrain, which
+		// is basically the height of the water table.
+		tn.rivers            = &noise_rivers->result[index];
+		// Valley depth noise is replaced with the valley
+		// number that represents the height of terrain
+		// over rivers and is used to determine about
+		// how close a river is for humidity calculation.
+		tn.valley            = &noise_valley_depth->result[index];
+		tn.valley_profile    = noise_valley_profile->result[index];
+		// Slope noise is replaced by the calculated slope
+		// which is used to get terrain height in the slow
+		// method, to create sharper mountains.
+		tn.slope             = &noise_inter_valley_slope->result[index];
+		tn.inter_valley_fill = noise_inter_valley_fill->result[index];
+
+		// This is the actual terrain height.
+		float mount = terrainLevelFromNoise(&tn);
+		noise_terrain_height->result[index] = mount;
+	}
+}
+
+
+// This keeps us from having to maintain two similar sets of
+//  complicated code to determine ground level.
+float MapgenValleys::terrainLevelFromNoise(TerrainNoise *tn)
+{
+	// The square function changes the behaviour of this noise:
+	//  very often small, and sometimes very high.
+	float valley_d = MYSQUARE(*tn->valley);
+
+	// valley_d is here because terrain is generally higher where valleys
+	//  are deep (mountains). base represents the height of the
+	//  rivers, most of the surface is above.
+	float base = tn->terrain_height + valley_d;
+
+	// "river" represents the distance from the river, in arbitrary units.
+	float river = fabs(*tn->rivers) - river_size_factor;
+
+	// Use the curve of the function 1-exp(-(x/a)^2) to model valleys.
+	//  Making "a" vary (0 < a <= 1) changes the shape of the valleys.
+	//  Try it with a geometry software !
+	//   (here x = "river" and a = valley_profile).
+	//  "valley" represents the height of the terrain, from the rivers.
+	{
+		float t = river / tn->valley_profile;
+		*tn->valley = valley_d * (1.f - exp(- MYSQUARE(t)));
+	}
+
+	// approximate height of the terrain at this point
+	float mount = base + *tn->valley;
+
+	*tn->slope *= *tn->valley;
+
+	// Rivers are placed where "river" is negative, so where the original
+	//  noise value is close to zero.
+	// Base ground is returned as rivers since it's basically the water table.
+	*tn->rivers = base;
+	if (river < 0.f) {
+		// Use the the function -sqrt(1-x^2) which models a circle.
+		float depth;
+		{
+			float t = river / river_size_factor + 1;
+			depth = (river_depth_bed * sqrt(MYMAX(0, 1.f - MYSQUARE(t))));
+		}
+
+		// base - depth : height of the bottom of the river
+		// water_level - 3 : don't make rivers below 3 nodes under the surface
+		// We use three because that's as low as the swamp biomes go.
+		// There is no logical equivalent to this using rangelim.
+		mount = MYMIN(MYMAX(base - depth, (float)(water_level - 3)), mount);
+
+		// Slope has no influence on rivers.
+		*tn->slope = 0.f;
+	}
+
+	return mount;
+}
+
+
+// This avoids duplicating the code in terrainLevelFromNoise, adding
+// only the final step of terrain generation without a noise map.
+float MapgenValleys::adjustedTerrainLevelFromNoise(TerrainNoise *tn)
+{
+	float mount = terrainLevelFromNoise(tn);
+	s16 y_start = myround(mount);
+
+	for (s16 y = y_start; y <= y_start + 1000; y++) {
+		float fill = NoisePerlin3D(&noise_inter_valley_fill->np, tn->x, y, tn->z, seed);
+
+		if (fill * *tn->slope < y - mount) {
+			mount = MYMAX(y - 1, mount);
+			break;
+		}
+	}
+
+	return mount;
+}
+
+
+int MapgenValleys::getSpawnLevelAtPoint(v2s16 p)
+{
+	// Check to make sure this isn't a request for a location in a river.
+	float rivers = NoisePerlin2D(&noise_rivers->np, p.X, p.Y, seed);
+	if (fabs(rivers) < river_size_factor)
+		return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
+
+	s16 level_at_point = terrainLevelAtPoint(p.X, p.Y);
+	if (level_at_point <= water_level ||
+			level_at_point > water_level + 32)
+		return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
+
+	return level_at_point;
+}
+
+
+float MapgenValleys::terrainLevelAtPoint(s16 x, s16 z)
+{
+	TerrainNoise tn;
+
+	float rivers = NoisePerlin2D(&noise_rivers->np, x, z, seed);
+	float valley = NoisePerlin2D(&noise_valley_depth->np, x, z, seed);
+	float inter_valley_slope = NoisePerlin2D(&noise_inter_valley_slope->np, x, z, seed);
+
+	tn.x                 = x;
+	tn.z                 = z;
+	tn.terrain_height    = NoisePerlin2D(&noise_terrain_height->np, x, z, seed);
+	tn.rivers            = &rivers;
+	tn.valley            = &valley;
+	tn.valley_profile    = NoisePerlin2D(&noise_valley_profile->np, x, z, seed);
+	tn.slope             = &inter_valley_slope;
+	tn.inter_valley_fill = 0.f;
+
+	return adjustedTerrainLevelFromNoise(&tn);
+}
+
+
+int MapgenValleys::generateTerrain()
+{
+	// Raising this reduces the rate of evaporation.
+	static const float evaporation = 300.f;
+	// from the lua
+	static const float humidity_dropoff = 4.f;
+	// constant to convert altitude chill (compatible with lua) to heat
+	static const float alt_to_heat = 20.f;
+	// humidity reduction by altitude
+	static const float alt_to_humid = 10.f;
+
+	MapNode n_air(CONTENT_AIR);
+	MapNode n_river_water(c_river_water_source);
+	MapNode n_stone(c_stone);
+	MapNode n_water(c_water_source);
+
+	const v3s16 &em = vm->m_area.getExtent();
+	s16 surface_max_y = -MAX_MAP_GENERATION_LIMIT;
+	u32 index_2d = 0;
+
+	for (s16 z = node_min.Z; z <= node_max.Z; z++)
+	for (s16 x = node_min.X; x <= node_max.X; x++, index_2d++) {
+		float river_y = noise_rivers->result[index_2d];
+		float surface_y = noise_terrain_height->result[index_2d];
+		float slope = noise_inter_valley_slope->result[index_2d];
+		float t_heat = m_bgen->heatmap[index_2d];
+
+		heightmap[index_2d] = -MAX_MAP_GENERATION_LIMIT;
+
+		if (surface_y > surface_max_y)
+			surface_max_y = ceil(surface_y);
+
+		if (humid_rivers) {
+			// Derive heat from (base) altitude. This will be most correct
+			// at rivers, since other surface heights may vary below.
+			if (use_altitude_chill && (surface_y > 0.f || river_y > 0.f))
+				t_heat -= alt_to_heat * MYMAX(surface_y, river_y) / altitude_chill;
+
+			// If humidity is low or heat is high, lower the water table.
+			float delta = m_bgen->humidmap[index_2d] - 50.f;
+			if (delta < 0.f) {
+				float t_evap = (t_heat - 32.f) / evaporation;
+				river_y += delta * MYMAX(t_evap, 0.08f);
+			}
+		}
+
+		u32 index_3d = (z - node_min.Z) * zstride_1u1d + (x - node_min.X);
+		u32 index_data = vm->m_area.index(x, node_min.Y - 1, z);
+
+		// Mapgens concern themselves with stone and water.
+		for (s16 y = node_min.Y - 1; y <= node_max.Y + 1; y++) {
+			if (vm->m_data[index_data].getContent() == CONTENT_IGNORE) {
+				float fill = noise_inter_valley_fill->result[index_3d];
+				float surface_delta = (float)y - surface_y;
+				bool river = y + 1 < river_y;
+
+				if (slope * fill > surface_delta) {
+					// ground
+					vm->m_data[index_data] = n_stone;
+					if (y > heightmap[index_2d])
+						heightmap[index_2d] = y;
+					if (y > surface_max_y)
+						surface_max_y = y;
+				} else if (y <= water_level) {
+					// sea
+					vm->m_data[index_data] = n_water;
+				} else if (river) {
+					// river
+					vm->m_data[index_data] = n_river_water;
+				} else {  // air
+					vm->m_data[index_data] = n_air;
+				}
+			}
+
+			vm->m_area.add_y(em, index_data, 1);
+			index_3d += ystride;
+		}
+
+		if (heightmap[index_2d] == -MAX_MAP_GENERATION_LIMIT) {
+			s16 surface_y_int = myround(surface_y);
+			if (surface_y_int > node_max.Y + 1 || surface_y_int < node_min.Y - 1) {
+				// If surface_y is outside the chunk, it's good enough.
+				heightmap[index_2d] = surface_y_int;
+			} else {
+				// If the ground is outside of this chunk, but surface_y
+				// is within the chunk, give a value outside.
+				heightmap[index_2d] = node_min.Y - 2;
+			}
+		}
+
+		if (humid_rivers) {
+			// Use base ground (water table) in a riverbed, to
+			// avoid an unnatural rise in humidity.
+			float t_alt = MYMAX(noise_rivers->result[index_2d], (float)heightmap[index_2d]);
+			float humid = m_bgen->humidmap[index_2d];
+			float water_depth = (t_alt - river_y) / humidity_dropoff;
+			humid *= 1.f + pow(0.5f, MYMAX(water_depth, 1.f));
+
+			// Reduce humidity with altitude (ignoring riverbeds).
+			// This is similar to the lua version's seawater adjustment,
+			// but doesn't increase the base humidity, which causes
+			// problems with the default biomes.
+			if (t_alt > 0.f)
+				humid -= alt_to_humid * t_alt / altitude_chill;
+
+			m_bgen->humidmap[index_2d] = humid;
+		}
+
+		// Assign the heat adjusted by any changed altitudes.
+		// The altitude will change about half the time.
+		if (use_altitude_chill) {
+			// ground height ignoring riverbeds
+			float t_alt = MYMAX(noise_rivers->result[index_2d], (float)heightmap[index_2d]);
+			if (humid_rivers && heightmap[index_2d] == (s16)myround(surface_y))
+				// The altitude hasn't changed. Use the first result.
+				m_bgen->heatmap[index_2d] = t_heat;
+			else if (t_alt > 0.f)
+				m_bgen->heatmap[index_2d] -= alt_to_heat * t_alt / altitude_chill;
+		}
+	}
+
+	return surface_max_y;
+}
+
+void MapgenValleys::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);
+
+	PseudoRandom ps(blockseed + 72202);
+
+	MapNode n_air(CONTENT_AIR);
+	MapNode n_lava(c_lava_source);
+	MapNode n_water(c_river_water_source);
+
+	const v3s16 &em = vm->m_area.getExtent();
+
+	// Cave blend distance near YMIN, YMAX
+	const float massive_cave_blend = 128.f;
+	// noise threshold for massive caves
+	const float massive_cave_threshold = 0.6f;
+	// mct: 1 = small rare caves, 0.5 1/3rd ground volume, 0 = 1/2 ground volume.
+
+	float yblmin = -mapgen_limit + massive_cave_blend * 1.5f;
+	float yblmax = massive_cave_depth - massive_cave_blend * 1.5f;
+	bool made_a_big_one = false;
+
+	// Cache the tcave values as they only vary by altitude.
+	if (node_max.Y <= massive_cave_depth) {
+		noise_massive_caves->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
+
+		for (s16 y = node_min.Y - 1; y <= node_max.Y; y++) {
+			float tcave = massive_cave_threshold;
+
+			if (y < yblmin) {
+				float t = (yblmin - y) / massive_cave_blend;
+				tcave += MYSQUARE(t);
+			} else if (y > yblmax) {
+				float t = (y - yblmax) / massive_cave_blend;
+				tcave += MYSQUARE(t);
+			}
+
+			tcave_cache[y - node_min.Y + 1] = tcave;
+		}
+	}
+
+	// lava_depth varies between one and ten as you approach
+	//  the bottom of the world.
+	s16 lava_depth = ceil((lava_max_height - node_min.Y + 1) * 10.f / mapgen_limit);
+	// This allows random lava spawns to be less common at the surface.
+	s16 lava_chance = MYCUBE(lava_features_lim) * lava_depth;
+	// water_depth varies between ten and one on the way down.
+	s16 water_depth = ceil((mapgen_limit - abs(node_min.Y) + 1) * 10.f / mapgen_limit);
+	// This allows random water spawns to be more common at the surface.
+	s16 water_chance = MYCUBE(water_features_lim) * water_depth;
+
+	// Reduce the odds of overflows even further.
+	if (node_max.Y > water_level) {
+		lava_chance /= 3;
+		water_chance /= 3;
+	}
+
+	u32 index_2d = 0;
+	for (s16 z = node_min.Z; z <= node_max.Z; z++)
+	for (s16 x = node_min.X; x <= node_max.X; x++, index_2d++) {
+		Biome *biome = (Biome *)m_bmgr->getRaw(biomemap[index_2d]);
+		bool tunnel_air_above = false;
+		bool is_under_river = false;
+		bool underground = false;
+		u32 index_data = vm->m_area.index(x, node_max.Y, z);
+		u32 index_3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride + (x - node_min.X);
+
+		// Dig caves on down loop to check for air above.
+		// 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--,
+				index_3d -= ystride,
+				vm->m_area.add_y(em, index_data, -1)) {
+
+			float terrain = noise_terrain_height->result[index_2d];
+
+			// Saves some time.
+			if (y > terrain + 10)
+				continue;
+
+			if (y < terrain - 40)
+				underground = true;
+
+			// Dig massive caves.
+			if (node_max.Y <= massive_cave_depth
+					&& noise_massive_caves->result[index_3d]
+					> tcave_cache[y - node_min.Y + 1]) {
+				vm->m_data[index_data] = n_air;
+				made_a_big_one = true;
+				continue;
+			}
+
+			content_t c = vm->m_data[index_data].getContent();
+			// Detect river water to place riverbed nodes in tunnels
+			if (c == biome->c_river_water)
+				is_under_river = true;
+
+			float d1 = contour(noise_cave1->result[index_3d]);
+			float d2 = contour(noise_cave2->result[index_3d]);
+
+			if (d1 * d2 > cave_width && ndef->get(c).is_ground_content) {
+				// in a tunnel
+				vm->m_data[index_data] = n_air;
+				tunnel_air_above = true;
+			} else if (c == biome->c_filler || c == biome->c_stone) {
+				if (tunnel_air_above) {
+					// at the tunnel floor
+					s16 sr = ps.range(0, 39);
+					u32 j = index_data;
+					vm->m_area.add_y(em, j, 1);
+
+					if (sr > terrain - y) {
+						// Put biome nodes in tunnels near the surface
+						if (is_under_river)
+							vm->m_data[index_data] = MapNode(biome->c_riverbed);
+						else if (underground)
+							vm->m_data[index_data] = MapNode(biome->c_filler);
+						else
+							vm->m_data[index_data] = MapNode(biome->c_top);
+					} else if (sr < 3 && underground) {
+						sr = abs(ps.next());
+						if (lava_features_lim > 0 && y <= lava_max_height
+								&& c == biome->c_stone && sr < lava_chance)
+							vm->m_data[j] = n_lava;
+
+						sr -= lava_chance;
+
+						// If sr < 0 then we should have already placed lava --
+						// don't immediately dump water on it.
+						if (water_features_lim > 0 && y <= cave_water_max_height
+								&& sr >= 0 && sr < water_chance)
+							vm->m_data[j] = n_water;
+					}
+				}
+
+				tunnel_air_above = false;
+				underground = true;
+			} else {
+				tunnel_air_above = false;
+			}
+		}
+	}
+
+	if (node_max.Y <= large_cave_depth && !made_a_big_one) {
+		u32 bruises_count = ps.range(0, 2);
+		for (u32 i = 0; i < bruises_count; i++) {
+			CavesRandomWalk cave(ndef, &gennotify, seed, water_level,
+				c_water_source, c_lava_source, lava_max_height);
+
+			cave.makeCave(vm, node_min, node_max, &ps, true, max_stone_y, heightmap);
+		}
+	}
+}