Mgvalleys: Make river depth variation and humidity drop optional (#7532)
[oweals/minetest.git] / src / mapgen / mapgen_valleys.cpp
index bef4629a8019a40c39b5abae1d33946de91cc1db..0a0f93a75f054c11d643495db8c11d314ffb4d52 100644 (file)
@@ -32,6 +32,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "map.h"
 #include "nodedef.h"
 #include "voxelalgorithms.h"
+//#include "profiler.h" // For TimeTaker
 #include "settings.h" // For g_settings
 #include "emerge.h"
 #include "dungeongen.h"
@@ -43,26 +44,20 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <cmath>
 
 
-//#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}
+FlagDesc flagdesc_mapgen_valleys[] = {
+       {"altitude_chill",   MGVALLEYS_ALT_CHILL},
+       {"humid_rivers",     MGVALLEYS_HUMID_RIVERS},
+       {"vary_river_depth", MGVALLEYS_VARY_RIVER_DEPTH},
+       {"altitude_dry",     MGVALLEYS_ALT_DRY},
+       {NULL,               0}
 };
 
-///////////////////////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////////////////////////
 
 
-MapgenValleys::MapgenValleys(int mapgenid, MapgenValleysParams *params, EmergeManager *emerge)
+MapgenValleys::MapgenValleys(int mapgenid, MapgenValleysParams *params,
+       EmergeManager *emerge)
        : MapgenBasic(mapgenid, params, emerge)
 {
        // NOTE: MapgenValleys has a hard dependency on BiomeGenOriginal
@@ -72,13 +67,15 @@ MapgenValleys::MapgenValleys(int mapgenid, MapgenValleysParams *params, EmergeMa
 
        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);
+       river_depth_bed    = params->river_depth + 1.0f;
+       river_size_factor  = params->river_size / 100.0f;
+
        cave_width         = params->cave_width;
+       large_cave_depth   = params->large_cave_depth;
+       lava_depth         = params->lava_depth;
+       cavern_limit       = params->cavern_limit;
+       cavern_taper       = params->cavern_taper;
+       cavern_threshold   = params->cavern_threshold;
        dungeon_ymin       = params->dungeon_ymin;
        dungeon_ymax       = params->dungeon_ymax;
 
@@ -92,52 +89,40 @@ MapgenValleys::MapgenValleys(int mapgenid, MapgenValleysParams *params, EmergeMa
 
        //// 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);
+       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;
+       MapgenBasic::np_cave1   = params->np_cave1;
+       MapgenBasic::np_cave2   = params->np_cave2;
+       MapgenBasic::np_cavern  = params->np_cavern;
 
-       tcave_cache = new float[csize.Y + 2];
+       humidity_adjust    = bp->np_humidity.offset - 50.0f;
 }
 
 
 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)
+       np_filler_depth       (0.0,   1.2,  v3f(256,  256,  256),  1605,  3, 0.5,  2.0),
+       np_inter_valley_fill  (0.0,   1.0,  v3f(256,  512,  256),  1993,  6, 0.8,  2.0),
+       np_inter_valley_slope (0.5,   0.5,  v3f(128,  128,  128),  746,   1, 1.0,  2.0),
+       np_rivers             (0.0,   1.0,  v3f(256,  256,  256),  -6050, 5, 0.6,  2.0),
+       np_terrain_height     (-10.0, 50.0, v3f(1024, 1024, 1024), 5202,  6, 0.4,  2.0),
+       np_valley_depth       (5.0,   4.0,  v3f(512,  512,  512),  -1914, 1, 1.0,  2.0),
+       np_valley_profile     (0.6,   0.50, v3f(512,  512,  512),  777,   1, 1.0,  2.0),
+       np_cave1              (0.0,   12.0, v3f(61,   61,   61),   52534, 3, 0.5,  2.0),
+       np_cave2              (0.0,   12.0, v3f(67,   67,   67),   10325, 3, 0.5,  2.0),
+       np_cavern             (0.0,   1.0,  v3f(768,  256,  768),  59033, 6, 0.63, 2.0)
 {
 }
 
@@ -147,25 +132,27 @@ 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->getS16NoEx("mgvalleys_lava_depth",         lava_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->getS16NoEx("mgvalleys_cavern_limit",       cavern_limit);
+       settings->getS16NoEx("mgvalleys_cavern_taper",       cavern_taper);
+       settings->getFloatNoEx("mgvalleys_cavern_threshold", cavern_threshold);
        settings->getS16NoEx("mgvalleys_dungeon_ymin",       dungeon_ymin);
        settings->getS16NoEx("mgvalleys_dungeon_ymax",       dungeon_ymax);
 
-       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);
+
+       settings->getNoiseParams("mgvalleys_np_cave1",              np_cave1);
+       settings->getNoiseParams("mgvalleys_np_cave2",              np_cave2);
+       settings->getNoiseParams("mgvalleys_np_cavern",             np_cavern);
 }
 
 
@@ -174,29 +161,31 @@ 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->setS16("mgvalleys_lava_depth",         lava_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->setS16("mgvalleys_cavern_limit",       cavern_limit);
+       settings->setS16("mgvalleys_cavern_taper",       cavern_taper);
+       settings->setFloat("mgvalleys_cavern_threshold", cavern_threshold);
        settings->setS16("mgvalleys_dungeon_ymin",       dungeon_ymin);
        settings->setS16("mgvalleys_dungeon_ymax",       dungeon_ymax);
 
-       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);
+
+       settings->setNoiseParams("mgvalleys_np_cave1",              np_cave1);
+       settings->setNoiseParams("mgvalleys_np_cave2",              np_cave2);
+       settings->setNoiseParams("mgvalleys_np_cavern",             np_cavern);
 }
 
 
-///////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////
 
 
 void MapgenValleys::makeChunk(BlockMakeData *data)
@@ -211,12 +200,12 @@ void MapgenValleys::makeChunk(BlockMakeData *data)
                data->blockpos_requested.Y <= data->blockpos_max.Y &&
                data->blockpos_requested.Z <= data->blockpos_max.Z);
 
+       //TimeTaker t("makeChunk");
+
        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;
@@ -226,7 +215,7 @@ void MapgenValleys::makeChunk(BlockMakeData *data)
 
        blockseed = getBlockSeed2(full_node_min, seed);
 
-       // Generate biome noises.  Note this must be executed strictly before
+       // Generate biome noises. Note this must be executed strictly before
        // generateTerrain, because generateTerrain depends on intermediate
        // biome-related noises.
        m_bgen->calcBiomeNoise(node_min);
@@ -242,18 +231,32 @@ void MapgenValleys::makeChunk(BlockMakeData *data)
        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);
+       if (flags & MG_BIOMES)
+               generateBiomes();
+
+       // Generate tunnels, caverns and large randomwalk caves
+       if (flags & MG_CAVES) {
+               // Generate tunnels first as caverns confuse them
+               generateCavesNoiseIntersection(stone_surface_max_y);
+
+               // Generate caverns
+               bool near_cavern = generateCavernsNoise(stone_surface_max_y);
+
+               // Generate large randomwalk caves
+               if (near_cavern)
+                       // Disable large randomwalk caves in this mapchunk by setting
+                       // 'large cave depth' to world base. Avoids excessive liquid in
+                       // large caverns and floating blobs of overgenerated liquid.
+                       generateCavesRandomWalk(stone_surface_max_y,
+                               -MAX_MAP_GENERATION_LIMIT);
+               else
+                       generateCavesRandomWalk(stone_surface_max_y, large_cave_depth);
+       }
 
        // Dungeon creation
        if ((flags & MG_DUNGEONS) && full_node_min.Y >= dungeon_ymin &&
                        full_node_max.Y <= dungeon_ymax)
-               generateDungeons(stone_surface_max_y, mgstone_type, biome_stone);
+               generateDungeons(stone_surface_max_y);
 
        // Generate the registered decorations
        if (flags & MG_DECORATIONS)
@@ -263,38 +266,27 @@ void MapgenValleys::makeChunk(BlockMakeData *data)
        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");
+       if (flags & MG_BIOMES)
+               dustTopNodes();
 
        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);
+               calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
+                       full_node_min, full_node_max);
 
        this->generating = false;
+
+       //printf("makeChunk: %lums\n", t.stop());
 }
 
 
-// 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);
@@ -303,19 +295,14 @@ void MapgenValleys::calculateNoise()
 
        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;
-
+       float heat_offset = 0.0f;
+       float humidity_scale = 1.0f;
        // Altitude chill tends to reduce the average heat.
-       if (use_altitude_chill)
-               heat_offset = 5.f;
-
+       if (spflags & MGVALLEYS_ALT_CHILL)
+               heat_offset = 5.0f;
        // River humidity tends to increase the humidity range.
-       if (humid_rivers) {
+       if (spflags & MGVALLEYS_HUMID_RIVERS)
                humidity_scale = 0.8f;
-       }
 
        for (s32 index = 0; index < csize.X * csize.Z; index++) {
                m_bgen->heatmap[index] += heat_offset;
@@ -327,21 +314,19 @@ void MapgenValleys::calculateNoise()
        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).
+               // 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.
+               // 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.
+               // Valley depth noise is replaced with the valley number that represents
+               // the height of terrain over rivers and is used to determine 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.
+               // 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];
 
@@ -352,75 +337,69 @@ void MapgenValleys::calculateNoise()
 }
 
 
-// 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.
+       // 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.
+       // 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.
+       // "river" represents the distance from the river
        float river = std::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 = std::fmax(river / tn->valley_profile, 0.0f);
-               *tn->valley = valley_d * (1.f - std::exp(- MYSQUARE(t)));
-       }
+       // "valley" represents the height of the terrain, from the rivers.
+       float tv = std::fmax(river / tn->valley_profile, 0.0f);
+       *tn->valley = valley_d * (1.0f - std::exp(-MYSQUARE(tv)));
 
-       // approximate height of the terrain at this point
+       // 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 * std::sqrt(MYMAX(0, 1.f - MYSQUARE(t))));
-               }
+
+       // Rivers are placed where "river" is negative, so where the original noise
+       // value is close to zero.
+       if (river < 0.0f) {
+               // Use the the function -sqrt(1-x^2) which models a circle
+               float tr = river / river_size_factor + 1.0f;
+               float depth = (river_depth_bed *
+                       std::sqrt(std::fmax(0.0f, 1.0f - MYSQUARE(tr))));
 
                // base - depth : height of the bottom of the river
-               // water_level - 3 : don't make rivers below 3 nodes under the surface
+               // 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);
+               mount =
+                       std::fmin(std::fmax(base - depth, (float)(water_level - 3)), mount);
 
-               // Slope has no influence on rivers.
-               *tn->slope = 0.f;
+               // Slope has no influence on rivers
+               *tn->slope = 0.0f;
        }
 
        return mount;
 }
 
 
-// This avoids duplicating the code in terrainLevelFromNoise, adding
-// only the final step of terrain generation without a noise map.
+// 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);
-
+               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);
+                       mount = std::fmax((float)(y - 1), mount);
                        break;
                }
        }
@@ -431,14 +410,14 @@ float MapgenValleys::adjustedTerrainLevelFromNoise(TerrainNoise *tn)
 
 int MapgenValleys::getSpawnLevelAtPoint(v2s16 p)
 {
-       // Check to make sure this isn't a request for a location in a river.
+       // Check if in a river
        float rivers = NoisePerlin2D(&noise_rivers->np, p.X, p.Y, seed);
        if (std::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)
+                       level_at_point > water_level + 16)
                return MAX_MAP_GENERATION_LIMIT;  // Unsuitable spawn point
 
        return level_at_point;
@@ -451,7 +430,8 @@ float MapgenValleys::terrainLevelAtPoint(s16 x, s16 z)
 
        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);
+       float inter_valley_slope =
+               NoisePerlin2D(&noise_inter_valley_slope->np, x, z, seed);
 
        tn.x                 = x;
        tn.z                 = z;
@@ -460,7 +440,7 @@ float MapgenValleys::terrainLevelAtPoint(s16 x, s16 z)
        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;
+       tn.inter_valley_fill = 0.0f;
 
        return adjustedTerrainLevelFromNoise(&tn);
 }
@@ -468,14 +448,13 @@ float MapgenValleys::terrainLevelAtPoint(s16 x, s16 z)
 
 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;
+       // Raising this reduces the rate of evaporation
+       static const float evaporation = 300.0f;
+       static const float humidity_dropoff = 4.0f;
+       // Constant to convert altitude chill to heat
+       static const float alt_to_heat = 20.0f;
+       // Humidity reduction by altitude
+       static const float alt_to_humid = 10.0f;
 
        MapNode n_air(CONTENT_AIR);
        MapNode n_river_water(c_river_water_source);
@@ -498,45 +477,41 @@ int MapgenValleys::generateTerrain()
                if (surface_y > surface_max_y)
                        surface_max_y = std::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);
+               // Optionally vary river depth according to heat and humidity
+               if (spflags & MGVALLEYS_VARY_RIVER_DEPTH) {
+                       float heat = ((spflags & MGVALLEYS_ALT_CHILL) &&
+                               (surface_y > 0.0f || river_y > 0.0f)) ?
+                               t_heat - alt_to_heat *
+                                       std::fmax(surface_y, river_y) / altitude_chill :
+                               t_heat;
+                       float delta = m_bgen->humidmap[index_2d] - 50.0f;
+                       if (delta < 0.0f) {
+                               float t_evap = (heat - 32.0f) / evaporation;
+                               river_y += delta * std::fmax(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;
+                               bool river = y < river_y - 1;
 
                                if (slope * fill > surface_delta) {
-                                       // ground
-                                       vm->m_data[index_data] = n_stone;
+                                       vm->m_data[index_data] = n_stone; // 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;
+                                       vm->m_data[index_data] = n_water; // Water
                                } else if (river) {
-                                       // river
-                                       vm->m_data[index_data] = n_river_water;
-                               } else {  // air
-                                       vm->m_data[index_data] = n_air;
+                                       vm->m_data[index_data] = n_river_water; // River water
+                               } else {
+                                       vm->m_data[index_data] = n_air; // Air
                                }
                        }
 
@@ -546,207 +521,48 @@ int MapgenValleys::generateTerrain()
 
                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.
+
+                       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.
+                               // 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];
+               // Optionally increase humidity around rivers
+               if (spflags & MGVALLEYS_HUMID_RIVERS) {
+                       // Ground height ignoring riverbeds
+                       float t_alt = std::fmax(noise_rivers->result[index_2d],
+                               (float)heightmap[index_2d]);
                        float water_depth = (t_alt - river_y) / humidity_dropoff;
-                       humid *= 1.f + std::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;
+                       m_bgen->humidmap[index_2d] *=
+                               1.0f + std::pow(0.5f, std::fmax(water_depth, 1.0f));
                }
-       }
-
-       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;
+               // Optionally decrease humidity with altitude
+               if (spflags & MGVALLEYS_ALT_DRY) {
+                       // Ground height ignoring riverbeds
+                       float t_alt = std::fmax(noise_rivers->result[index_2d],
+                               (float)heightmap[index_2d]);
+                       if (t_alt > 0.0f)
+                               m_bgen->humidmap[index_2d] -=
+                                       alt_to_humid * t_alt / altitude_chill;
                }
-       }
-
-       // lava_depth varies between one and ten as you approach
-       //  the bottom of the world.
-       s16 lava_depth = std::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 = std::ceil((mapgen_limit - std::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,
-                               VoxelArea::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;
-                                       VoxelArea::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;
-                       }
+               // Optionally decrease heat with altitude
+               if (spflags & MGVALLEYS_ALT_CHILL) {
+                       // Ground height ignoring riverbeds
+                       float t_alt = std::fmax(noise_rivers->result[index_2d],
+                               (float)heightmap[index_2d]);
+                       if (t_alt > 0.0f)
+                               m_bgen->heatmap[index_2d] -=
+                                       alt_to_heat * t_alt / altitude_chill;
                }
        }
 
-       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);
-               }
-       }
+       return surface_max_y;
 }