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/*
Minetest
Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>

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.
*/

#pragma once

#include "irrlichttypes.h"

#include <vector2d.h>

typedef core::vector2d<f32> v2f;
typedef core::vector2d<s16> v2s16;
typedef core::vector2d<s32> v2s32;
typedef core::vector2d<u32> v2u32;
typedef core::vector2d<f32> v2f32;
='#n112'>112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528
/*
Minetest
Copyright (C) 2013-2019 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
Copyright (C) 2014-2019 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 <cmath>
#include "voxel.h"
#include "noise.h"
#include "mapblock.h"
#include "mapnode.h"
#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"
#include "cavegen.h"
#include "mg_biome.h"
#include "mg_ore.h"
#include "mg_decoration.h"
#include "mapgen_v7.h"


FlagDesc flagdesc_mapgen_v7[] = {
	{"mountains",   MGV7_MOUNTAINS},
	{"ridges",      MGV7_RIDGES},
	{"floatlands",  MGV7_FLOATLANDS},
	{"caverns",     MGV7_CAVERNS},
	{NULL,          0}
};


////////////////////////////////////////////////////////////////////////////////


MapgenV7::MapgenV7(MapgenV7Params *params, EmergeManager *emerge)
	: MapgenBasic(MAPGEN_V7, params, emerge)
{
	spflags            = params->spflags;
	mount_zero_level   = params->mount_zero_level;

	cave_width         = params->cave_width;
	large_cave_depth   = params->large_cave_depth;
	small_cave_num_min = params->small_cave_num_min;
	small_cave_num_max = params->small_cave_num_max;
	large_cave_num_min = params->large_cave_num_min;
	large_cave_num_max = params->large_cave_num_max;
	large_cave_flooded = params->large_cave_flooded;
	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;

	// 2D noise
	noise_terrain_base =
		new Noise(&params->np_terrain_base,    seed, csize.X, csize.Z);
	noise_terrain_alt =
		new Noise(&params->np_terrain_alt,     seed, csize.X, csize.Z);
	noise_terrain_persist =
		new Noise(&params->np_terrain_persist, seed, csize.X, csize.Z);
	noise_height_select =
		new Noise(&params->np_height_select,   seed, csize.X, csize.Z);
	noise_filler_depth =
		new Noise(&params->np_filler_depth,    seed, csize.X, csize.Z);

	if (spflags & MGV7_MOUNTAINS) {
		// 2D noise
		noise_mount_height =
			new Noise(&params->np_mount_height, seed, csize.X, csize.Z);
		// 3D noise, 1 up, 1 down overgeneration
		noise_mountain =
			new Noise(&params->np_mountain,     seed, csize.X, csize.Y + 2, csize.Z);
	}

	if (spflags & MGV7_RIDGES) {
		// 2D noise
		noise_ridge_uwater =
			new Noise(&params->np_ridge_uwater, seed, csize.X, csize.Z);
		// 3D noise, 1 up, 1 down overgeneration
		noise_ridge =
			new Noise(&params->np_ridge,        seed, csize.X, csize.Y + 2, csize.Z);
	}

	// 3D noise, 1 down overgeneration
	MapgenBasic::np_cave1    = params->np_cave1;
	MapgenBasic::np_cave2    = params->np_cave2;
	MapgenBasic::np_cavern   = params->np_cavern;
	// 3D noise
	MapgenBasic::np_dungeons = params->np_dungeons;
}


MapgenV7::~MapgenV7()
{
	delete noise_terrain_base;
	delete noise_terrain_alt;
	delete noise_terrain_persist;
	delete noise_height_select;
	delete noise_filler_depth;

	if (spflags & MGV7_MOUNTAINS) {
		delete noise_mount_height;
		delete noise_mountain;
	}

	if (spflags & MGV7_RIDGES) {
		delete noise_ridge_uwater;
		delete noise_ridge;
	}
}


MapgenV7Params::MapgenV7Params():
	np_terrain_base      (4.0,   70.0,  v3f(600,  600,  600),  82341, 5, 0.6,  2.0),
	np_terrain_alt       (4.0,   25.0,  v3f(600,  600,  600),  5934,  5, 0.6,  2.0),
	np_terrain_persist   (0.6,   0.1,   v3f(2000, 2000, 2000), 539,   3, 0.6,  2.0),
	np_height_select     (-8.0,  16.0,  v3f(500,  500,  500),  4213,  6, 0.7,  2.0),
	np_filler_depth      (0.0,   1.2,   v3f(150,  150,  150),  261,   3, 0.7,  2.0),
	np_mount_height      (256.0, 112.0, v3f(1000, 1000, 1000), 72449, 3, 0.6,  2.0),
	np_ridge_uwater      (0.0,   1.0,   v3f(1000, 1000, 1000), 85039, 5, 0.6,  2.0),
	np_mountain          (-0.6,  1.0,   v3f(250,  350,  250),  5333,  5, 0.63, 2.0),
	np_ridge             (0.0,   1.0,   v3f(100,  100,  100),  6467,  4, 0.75, 2.0),
	np_cavern            (0.0,   1.0,   v3f(384,  128,  384),  723,   5, 0.63, 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_dungeons          (0.9,   0.5,   v3f(500,  500,  500),  0,     2, 0.8,  2.0)
{
}


void MapgenV7Params::readParams(const Settings *settings)
{
	settings->getFlagStrNoEx("mgv7_spflags", spflags, flagdesc_mapgen_v7);
	settings->getS16NoEx("mgv7_mount_zero_level",       mount_zero_level);
	settings->getFloatNoEx("mgv7_cave_width",           cave_width);
	settings->getS16NoEx("mgv7_large_cave_depth",       large_cave_depth);
	settings->getU16NoEx("mgv7_small_cave_num_min",     small_cave_num_min);
	settings->getU16NoEx("mgv7_small_cave_num_max",     small_cave_num_max);
	settings->getU16NoEx("mgv7_large_cave_num_min",     large_cave_num_min);
	settings->getU16NoEx("mgv7_large_cave_num_max",     large_cave_num_max);
	settings->getFloatNoEx("mgv7_large_cave_flooded",   large_cave_flooded);
	settings->getS16NoEx("mgv7_cavern_limit",           cavern_limit);
	settings->getS16NoEx("mgv7_cavern_taper",           cavern_taper);
	settings->getFloatNoEx("mgv7_cavern_threshold",     cavern_threshold);
	settings->getS16NoEx("mgv7_dungeon_ymin",           dungeon_ymin);
	settings->getS16NoEx("mgv7_dungeon_ymax",           dungeon_ymax);

	settings->getNoiseParams("mgv7_np_terrain_base",    np_terrain_base);
	settings->getNoiseParams("mgv7_np_terrain_alt",     np_terrain_alt);
	settings->getNoiseParams("mgv7_np_terrain_persist", np_terrain_persist);
	settings->getNoiseParams("mgv7_np_height_select",   np_height_select);
	settings->getNoiseParams("mgv7_np_filler_depth",    np_filler_depth);
	settings->getNoiseParams("mgv7_np_mount_height",    np_mount_height);
	settings->getNoiseParams("mgv7_np_ridge_uwater",    np_ridge_uwater);
	settings->getNoiseParams("mgv7_np_mountain",        np_mountain);
	settings->getNoiseParams("mgv7_np_ridge",           np_ridge);
	settings->getNoiseParams("mgv7_np_cavern",          np_cavern);
	settings->getNoiseParams("mgv7_np_cave1",           np_cave1);
	settings->getNoiseParams("mgv7_np_cave2",           np_cave2);
	settings->getNoiseParams("mgv7_np_dungeons",        np_dungeons);
}


void MapgenV7Params::writeParams(Settings *settings) const
{
	settings->setFlagStr("mgv7_spflags", spflags, flagdesc_mapgen_v7);
	settings->setS16("mgv7_mount_zero_level",           mount_zero_level);
	settings->setFloat("mgv7_cave_width",               cave_width);
	settings->setS16("mgv7_large_cave_depth",           large_cave_depth);
	settings->setU16("mgv7_small_cave_num_min",         small_cave_num_min);
	settings->setU16("mgv7_small_cave_num_max",         small_cave_num_max);
	settings->setU16("mgv7_large_cave_num_min",         large_cave_num_min);
	settings->setU16("mgv7_large_cave_num_max",         large_cave_num_max);
	settings->setFloat("mgv7_large_cave_flooded",       large_cave_flooded);
	settings->setS16("mgv7_cavern_limit",               cavern_limit);
	settings->setS16("mgv7_cavern_taper",               cavern_taper);
	settings->setFloat("mgv7_cavern_threshold",         cavern_threshold);
	settings->setS16("mgv7_dungeon_ymin",               dungeon_ymin);
	settings->setS16("mgv7_dungeon_ymax",               dungeon_ymax);

	settings->setNoiseParams("mgv7_np_terrain_base",    np_terrain_base);
	settings->setNoiseParams("mgv7_np_terrain_alt",     np_terrain_alt);
	settings->setNoiseParams("mgv7_np_terrain_persist", np_terrain_persist);
	settings->setNoiseParams("mgv7_np_height_select",   np_height_select);
	settings->setNoiseParams("mgv7_np_filler_depth",    np_filler_depth);
	settings->setNoiseParams("mgv7_np_mount_height",    np_mount_height);
	settings->setNoiseParams("mgv7_np_ridge_uwater",    np_ridge_uwater);
	settings->setNoiseParams("mgv7_np_mountain",        np_mountain);
	settings->setNoiseParams("mgv7_np_ridge",           np_ridge);
	settings->setNoiseParams("mgv7_np_cavern",          np_cavern);
	settings->setNoiseParams("mgv7_np_cave1",           np_cave1);
	settings->setNoiseParams("mgv7_np_cave2",           np_cave2);
	settings->setNoiseParams("mgv7_np_dungeons",        np_dungeons);
}


void MapgenV7Params::setDefaultSettings(Settings *settings)
{
	settings->setDefault("mgv7_spflags", flagdesc_mapgen_v7,
		MGV7_MOUNTAINS | MGV7_RIDGES | MGV7_CAVERNS);
}


////////////////////////////////////////////////////////////////////////////////


int MapgenV7::getSpawnLevelAtPoint(v2s16 p)
{
	// If rivers are enabled, first check if in a river
	if (spflags & MGV7_RIDGES) {
		float width = 0.2f;
		float uwatern = NoisePerlin2D(&noise_ridge_uwater->np, p.X, p.Y, seed) *
			2.0f;
		if (std::fabs(uwatern) <= width)
			return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point
	}

	// Terrain noise 'offset' is the average level of that terrain.
	// At least 50% of terrain will be below the higher of base and alt terrain
	// 'offset's.
	// Raising the maximum spawn level above 'water_level + 16' is necessary
	// for when terrain 'offset's are set much higher than water_level.
	s16 max_spawn_y = std::fmax(std::fmax(noise_terrain_alt->np.offset,
			noise_terrain_base->np.offset),
			water_level + 16);
	// Base terrain calculation
	s16 y = baseTerrainLevelAtPoint(p.X, p.Y);

	// If mountains are disabled, terrain level is base terrain level.
	// Avoids mid-air spawn where mountain terrain would have been.
	if (!(spflags & MGV7_MOUNTAINS)) {
		if (y < water_level || y > max_spawn_y)
			return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point

		// y + 2 because y is surface level and due to biome 'dust'
		return y + 2;
	}

	// Search upwards for first node without mountain terrain
	int iters = 256;
	while (iters > 0 && y <= max_spawn_y) {
		if (!getMountainTerrainAtPoint(p.X, y + 1, p.Y)) {
			if (y <= water_level || y > max_spawn_y)
				return MAX_MAP_GENERATION_LIMIT; // Unsuitable spawn point

			// y + 1 due to biome 'dust'
			return y + 1;
		}
		y++;
		iters--;
	}

	// Unsuitable spawn point
	return MAX_MAP_GENERATION_LIMIT;
}


void MapgenV7::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);

	//TimeTaker t("makeChunk");

	this->generating = true;
	this->vm = data->vmanip;
	this->ndef = data->nodedef;

	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 base and mountain terrain
	s16 stone_surface_max_y = generateTerrain();

	// Generate rivers
	if (spflags & MGV7_RIDGES)
		generateRidgeTerrain();

	// Create heightmap
	updateHeightmap(node_min, node_max);

	// Init biome generator, place biome-specific nodes, and build biomemap
	if (flags & MG_BIOMES) {
		biomegen->calcBiomeNoise(node_min);
		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 = false;
		if (spflags & MGV7_CAVERNS)
			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);
	}

	// Generate the registered ores
	m_emerge->oremgr->placeAllOres(this, blockseed, node_min, node_max);

	// Generate dungeons
	if (flags & MG_DUNGEONS)
		generateDungeons(stone_surface_max_y);

	// Generate the registered decorations
	if (flags & MG_DECORATIONS)
		m_emerge->decomgr->placeAllDecos(this, blockseed, node_min, node_max);

	// Sprinkle some dust on top after everything else was generated
	if (flags & MG_BIOMES)
		dustTopNodes();

	// Update liquids
	updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);

	// Calculate lighting
	// TODO disable in and just below floatlands
	bool propagate_shadow = true;

	if (flags & MG_LIGHT)
		calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0),
			full_node_min, full_node_max, propagate_shadow);

	this->generating = false;

	//printf("makeChunk: %lums\n", t.stop());
}


////////////////////////////////////////////////////////////////////////////////


float MapgenV7::baseTerrainLevelAtPoint(s16 x, s16 z)
{
	float hselect = NoisePerlin2D(&noise_height_select->np, x, z, seed);
	hselect = rangelim(hselect, 0.0f, 1.0f);

	float persist = NoisePerlin2D(&noise_terrain_persist->np, x, z, seed);

	noise_terrain_base->np.persist = persist;
	float height_base = NoisePerlin2D(&noise_terrain_base->np, x, z, seed);

	noise_terrain_alt->np.persist = persist;
	float height_alt = NoisePerlin2D(&noise_terrain_alt->np, x, z, seed);

	if (height_alt > height_base)
		return height_alt;

	return (height_base * hselect) + (height_alt * (1.0f - hselect));
}


float MapgenV7::baseTerrainLevelFromMap(int index)
{
	float hselect = rangelim(noise_height_select->result[index], 0.0f, 1.0f);
	float height_base = noise_terrain_base->result[index];
	float height_alt = noise_terrain_alt->result[index];

	if (height_alt > height_base)
		return height_alt;

	return (height_base * hselect) + (height_alt * (1.0f - hselect));
}


bool MapgenV7::getMountainTerrainAtPoint(s16 x, s16 y, s16 z)
{
	float mnt_h_n =
		std::fmax(NoisePerlin2D(&noise_mount_height->np, x, z, seed), 1.0f);
	float density_gradient = -((float)(y - mount_zero_level) / mnt_h_n);
	float mnt_n = NoisePerlin3D(&noise_mountain->np, x, y, z, seed);

	return mnt_n + density_gradient >= 0.0f;
}


bool MapgenV7::getMountainTerrainFromMap(int idx_xyz, int idx_xz, s16 y)
{
	float mounthn = std::fmax(noise_mount_height->result[idx_xz], 1.0f);
	float density_gradient = -((float)(y - mount_zero_level) / mounthn);
	float mountn = noise_mountain->result[idx_xyz];

	return mountn + density_gradient >= 0.0f;
}


int MapgenV7::generateTerrain()
{
	MapNode n_air(CONTENT_AIR);
	MapNode n_stone(c_stone);
	MapNode n_water(c_water_source);

	//// Calculate noise for terrain generation
	noise_terrain_persist->perlinMap2D(node_min.X, node_min.Z);
	float *persistmap = noise_terrain_persist->result;

	noise_terrain_base->perlinMap2D(node_min.X, node_min.Z, persistmap);
	noise_terrain_alt->perlinMap2D(node_min.X, node_min.Z, persistmap);
	noise_height_select->perlinMap2D(node_min.X, node_min.Z);

	if (spflags & MGV7_MOUNTAINS) {
		noise_mount_height->perlinMap2D(node_min.X, node_min.Z);
		noise_mountain->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
	}

	//// Place nodes
	const v3s16 &em = vm->m_area.getExtent();
	s16 stone_surface_max_y = -MAX_MAP_GENERATION_LIMIT;
	u32 index2d = 0;

	for (s16 z = node_min.Z; z <= node_max.Z; z++)
	for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
		s16 surface_y = baseTerrainLevelFromMap(index2d);
		if (surface_y > stone_surface_max_y)
			stone_surface_max_y = surface_y;

		u32 vi = vm->m_area.index(x, node_min.Y - 1, z);
		u32 index3d = (z - node_min.Z) * zstride_1u1d + (x - node_min.X);

		for (s16 y = node_min.Y - 1; y <= node_max.Y + 1;
				y++,
				index3d += ystride,
				VoxelArea::add_y(em, vi, 1)) {
			if (vm->m_data[vi].getContent() != CONTENT_IGNORE)
				continue;

			if (y <= surface_y) {
				vm->m_data[vi] = n_stone; // Base terrain
			} else if ((spflags & MGV7_MOUNTAINS) &&
					getMountainTerrainFromMap(index3d, index2d, y)) {
				vm->m_data[vi] = n_stone; // Mountain terrain
				if (y > stone_surface_max_y)
					stone_surface_max_y = y;
			} else if (y <= water_level) {
				vm->m_data[vi] = n_water;
			} else {
				vm->m_data[vi] = n_air;
			}
		}
	}

	return stone_surface_max_y;
}


void MapgenV7::generateRidgeTerrain()
{
	// TODO disable river canyons in floatlands
	if (node_max.Y < water_level - 16)
		return;

	noise_ridge->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
	noise_ridge_uwater->perlinMap2D(node_min.X, node_min.Z);

	MapNode n_water(c_water_source);
	MapNode n_air(CONTENT_AIR);
	u32 index3d = 0;
	float width = 0.2f;

	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 vi = vm->m_area.index(node_min.X, y, z);
		for (s16 x = node_min.X; x <= node_max.X; x++, index3d++, vi++) {
			u32 index2d = (z - node_min.Z) * csize.X + (x - node_min.X);
			float uwatern = noise_ridge_uwater->result[index2d] * 2.0f;
			if (std::fabs(uwatern) > width)
				continue;
			// Optimises, but also avoids removing nodes placed by mods in
			// 'on-generated', when generating outside mapchunk.
			content_t c = vm->m_data[vi].getContent();
			if (c != c_stone)
				continue;

			float altitude = y - water_level;
			float height_mod = (altitude + 17.0f) / 2.5f;
			float width_mod = width - std::fabs(uwatern);
			float nridge = noise_ridge->result[index3d] *
				std::fmax(altitude, 0.0f) / 7.0f;
			if (nridge + width_mod * height_mod < 0.6f)
				continue;

			vm->m_data[vi] = (y > water_level) ? n_air : n_water;
		}
	}
}