minetest/src/script/lua_api/l_mapgen.cpp

/*
Minetest
Copyright (C) 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.
*/

#include "lua_api/l_mapgen.h"
#include "lua_api/l_internal.h"
#include "lua_api/l_vmanip.h"
#include "common/c_converter.h"
#include "common/c_content.h"
#include "util/serialize.h"
#include "server.h"
#include "environment.h"
#include "emerge.h"
#include "mg_biome.h"
#include "mg_ore.h"
#include "mg_decoration.h"
#include "mg_schematic.h"
#include "mapgen_v5.h"
#include "mapgen_v7.h"
#include "filesys.h"
#include "settings.h"
#include "log.h"


struct EnumString ModApiMapgen::es_BiomeTerrainType[] =
{
	{BIOME_NORMAL, "normal"},
	{BIOME_LIQUID, "liquid"},
	{BIOME_NETHER, "nether"},
	{BIOME_AETHER, "aether"},
	{BIOME_FLAT,   "flat"},
	{0, NULL},
};

struct EnumString ModApiMapgen::es_DecorationType[] =
{
	{DECO_SIMPLE,    "simple"},
	{DECO_SCHEMATIC, "schematic"},
	{DECO_LSYSTEM,   "lsystem"},
	{0, NULL},
};

struct EnumString ModApiMapgen::es_MapgenObject[] =
{
	{MGOBJ_VMANIP,    "voxelmanip"},
	{MGOBJ_HEIGHTMAP, "heightmap"},
	{MGOBJ_BIOMEMAP,  "biomemap"},
	{MGOBJ_HEATMAP,   "heatmap"},
	{MGOBJ_HUMIDMAP,  "humiditymap"},
	{MGOBJ_GENNOTIFY, "gennotify"},
	{0, NULL},
};

struct EnumString ModApiMapgen::es_OreType[] =
{
	{ORE_SCATTER, "scatter"},
	{ORE_SHEET,   "sheet"},
	{ORE_BLOB,    "blob"},
	{ORE_VEIN,    "vein"},
	{0, NULL},
};

struct EnumString ModApiMapgen::es_Rotation[] =
{
	{ROTATE_0,    "0"},
	{ROTATE_90,   "90"},
	{ROTATE_180,  "180"},
	{ROTATE_270,  "270"},
	{ROTATE_RAND, "random"},
	{0, NULL},
};


ObjDef *get_objdef(lua_State *L, int index, ObjDefManager *objmgr);

Biome *get_or_load_biome(lua_State *L, int index,
	BiomeManager *biomemgr);
Biome *read_biome_def(lua_State *L, int index, INodeDefManager *ndef);
size_t get_biome_list(lua_State *L, int index,
	BiomeManager *biomemgr, std::set<u8> *biome_id_list);

Schematic *get_or_load_schematic(lua_State *L, int index,
	SchematicManager *schemmgr, StringMap *replace_names);
Schematic *read_schematic_def(lua_State *L, int index,
	INodeDefManager *ndef, StringMap *replace_names);
Schematic *load_schematic(lua_State *L, int index,
	SchematicManager *schemmgr, StringMap *replace_names);

bool read_deco_simple(lua_State *L, NodeResolveInfo *nri, DecoSimple *deco);
bool read_deco_schematic(lua_State *L, SchematicManager *schemmgr, DecoSchematic *deco);


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


ObjDef *get_objdef(lua_State *L, int index, ObjDefManager *objmgr)
{
	if (index < 0)
		index = lua_gettop(L) + 1 + index;

	// If a number, assume this is a handle to an object def
	if (lua_isnumber(L, index))
		return objmgr->get(lua_tointeger(L, index));

	// If a string, assume a name is given instead
	if (lua_isstring(L, index))
		return objmgr->getByName(lua_tostring(L, index));

	return NULL;
}


Schematic *load_schematic(lua_State *L, int index,
	SchematicManager *schemmgr, StringMap *replace_names)
{
	if (index < 0)
		index = lua_gettop(L) + 1 + index;

	Schematic *schem;

	if (lua_istable(L, index)) {
		schem = read_schematic_def(L, index, schemmgr->getNodeDef(), replace_names);
		if (!schem) {
			delete schem;
			return NULL;
		}
	} else if (lua_isnumber(L, index)) {
		return NULL;
	} else if (lua_isstring(L, index)) {
		schem = SchematicManager::create(SCHEMATIC_NORMAL);

		std::string filepath = lua_tostring(L, index);
		if (!fs::IsPathAbsolute(filepath))
			filepath = ModApiBase::getCurrentModPath(L) + DIR_DELIM + filepath;

		if (!schem->loadSchematicFromFile(filepath.c_str(),
				schemmgr->getNodeDef(), replace_names)) {
			delete schem;
			return NULL;
		}
	} else {
		return NULL;
	}

	return schem;
}


Biome *get_or_load_biome(lua_State *L, int index, BiomeManager *biomemgr)
{
	if (index < 0)
		index = lua_gettop(L) + 1 + index;

	Biome *biome = (Biome *)get_objdef(L, index, biomemgr);
	if (biome)
		return biome;

	biome = read_biome_def(L, index, biomemgr->getNodeDef());
	if (!biome)
		return NULL;

	if (biomemgr->add(biome) == OBJDEF_INVALID_HANDLE) {
		delete biome;
		return NULL;
	}

	return biome;
}


Biome *read_biome_def(lua_State *L, int index, INodeDefManager *ndef)
{
	if (!lua_istable(L, index))
		return NULL;

	BiomeType biometype = (BiomeType)getenumfield(L, index, "type",
		ModApiMapgen::es_BiomeTerrainType, BIOME_NORMAL);
	Biome *b = BiomeManager::create(biometype);

	b->name            = getstringfield_default(L, index, "name", "");
	b->depth_top       = getintfield_default(L, index, "depth_top",          1);
	b->depth_filler    = getintfield_default(L, index, "depth_filler",       2);
	b->depth_water_top = getintfield_default(L, index, "depth_water_top",    0);
	b->y_min           = getintfield_default(L, index, "y_min",         -31000);
	b->y_max           = getintfield_default(L, index, "y_max",          31000);
	b->heat_point      = getfloatfield_default(L, index, "heat_point",     0.f);
	b->humidity_point  = getfloatfield_default(L, index, "humidity_point", 0.f);
	b->flags           = 0; //reserved

	NodeResolveInfo *nri = new NodeResolveInfo(b);
	std::list<std::string> &nnames = nri->nodenames;
	nnames.push_back(getstringfield_default(L, index, "node_top",       ""));
	nnames.push_back(getstringfield_default(L, index, "node_filler",    ""));
	nnames.push_back(getstringfield_default(L, index, "node_stone",     ""));
	nnames.push_back(getstringfield_default(L, index, "node_water_top", ""));
	nnames.push_back(getstringfield_default(L, index, "node_water",     ""));
	nnames.push_back(getstringfield_default(L, index, "node_dust",      ""));
	ndef->pendNodeResolve(nri);

	return b;
}


size_t get_biome_list(lua_State *L, int index,
	BiomeManager *biomemgr, std::set<u8> *biome_id_list)
{
	if (index < 0)
		index = lua_gettop(L) + 1 + index;

	if (lua_isnil(L, index))
		return 0;

	bool is_single = true;
	if (lua_istable(L, index)) {
		lua_getfield(L, index, "name");
		is_single = !lua_isnil(L, -1);
		lua_pop(L, 1);
	}

	if (is_single) {
		Biome *biome = get_or_load_biome(L, index, biomemgr);
		if (!biome) {
			errorstream << "get_biome_list: failed to get biome" << std::endl;
			return 1;
		}

		biome_id_list->insert(biome->index);
		return 0;
	}

	// returns number of failed resolutions
	size_t fail_count = 0;
	size_t count = 0;

	for (lua_pushnil(L); lua_next(L, index); lua_pop(L, 1)) {
		count++;
		Biome *biome = get_or_load_biome(L, -1, biomemgr);
		if (!biome) {
			fail_count++;
			errorstream << "get_biome_list: failed to load biome (index "
				<< count << ")" << std::endl;
			continue;
		}

		biome_id_list->insert(biome->index);
	}

	return fail_count;
}


Schematic *get_or_load_schematic(lua_State *L, int index,
	SchematicManager *schemmgr, StringMap *replace_names)
{
	if (index < 0)
		index = lua_gettop(L) + 1 + index;

	Schematic *schem = (Schematic *)get_objdef(L, index, schemmgr);
	if (schem)
		return schem;

	schem = load_schematic(L, index, schemmgr, replace_names);
	if (!schem)
		return NULL;

	if (schemmgr->add(schem) == OBJDEF_INVALID_HANDLE) {
		delete schem;
		return NULL;
	}

	return schem;
}


Schematic *read_schematic_def(lua_State *L, int index,
	INodeDefManager *ndef, StringMap *replace_names)
{
	if (!lua_istable(L, index))
		return NULL;

	//// Get schematic size
	lua_getfield(L, index, "size");
	v3s16 size = read_v3s16(L, -1);
	lua_pop(L, 1);

	//// Get schematic data
	lua_getfield(L, index, "data");
	luaL_checktype(L, -1, LUA_TTABLE);

	int numnodes = size.X * size.Y * size.Z;
	MapNode *schemdata = new MapNode[numnodes];
	int i = 0;

	lua_pushnil(L);
	while (lua_next(L, -2)) {
		if (i >= numnodes) {
			i++;
			lua_pop(L, 1);
			continue;
		}

		// same as readnode, except param1 default is MTSCHEM_PROB_CONST
		lua_getfield(L, -1, "name");
		std::string name = luaL_checkstring(L, -1);
		lua_pop(L, 1);

		u8 param1;
		lua_getfield(L, -1, "param1");
		param1 = !lua_isnil(L, -1) ? lua_tonumber(L, -1) : MTSCHEM_PROB_ALWAYS;
		lua_pop(L, 1);

		u8 param2;
		lua_getfield(L, -1, "param2");
		param2 = !lua_isnil(L, -1) ? lua_tonumber(L, -1) : 0;
		lua_pop(L, 1);

		StringMap::iterator it = replace_names->find(name);
		if (it != replace_names->end())
			name = it->second;

		schemdata[i] = MapNode(ndef, name, param1, param2);

		i++;
		lua_pop(L, 1);
	}

	if (i != numnodes) {
		errorstream << "read_schematic: incorrect number of "
			"nodes provided in raw schematic data (got " << i <<
			", expected " << numnodes << ")." << std::endl;
		delete schemdata;
		return NULL;
	}

	//// Get Y-slice probability values (if present)
	u8 *slice_probs = new u8[size.Y];
	for (i = 0; i != size.Y; i++)
		slice_probs[i] = MTSCHEM_PROB_ALWAYS;

	lua_getfield(L, index, "yslice_prob");
	if (lua_istable(L, -1)) {
		lua_pushnil(L);
		while (lua_next(L, -2)) {
			if (getintfield(L, -1, "ypos", i) && i >= 0 && i < size.Y) {
				slice_probs[i] = getintfield_default(L, -1,
					"prob", MTSCHEM_PROB_ALWAYS);
			}
			lua_pop(L, 1);
		}
	}

	Schematic *schem = SchematicManager::create(SCHEMATIC_NORMAL);

	// Here, we read the nodes directly from the INodeDefManager - there is no
	// need for pending node resolutions so we'll mark this schematic as updated
	schem->flags       = SCHEM_CIDS_UPDATED;

	schem->size        = size;
	schem->schemdata   = schemdata;
	schem->slice_probs = slice_probs;
	return schem;
}


void read_schematic_replacements(lua_State *L, int index, StringMap *replace_names)
{
	if (index < 0)
		index = lua_gettop(L) + 1 + index;

	lua_pushnil(L);
	while (lua_next(L, index)) {
		std::string replace_from;
		std::string replace_to;

		if (lua_istable(L, -1)) { // Old {{"x", "y"}, ...} format
			lua_rawgeti(L, -1, 1);
			replace_from = lua_tostring(L, -1);
			lua_pop(L, 1);

			lua_rawgeti(L, -1, 2);
			replace_to = lua_tostring(L, -1);
			lua_pop(L, 1);
		} else { // New {x = "y", ...} format
			replace_from = lua_tostring(L, -2);
			replace_to = lua_tostring(L, -1);
		}

		replace_names->insert(std::make_pair(replace_from, replace_to));
		lua_pop(L, 1);
	}
}


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


// get_mapgen_object(objectname)
// returns the requested object used during map generation
int ModApiMapgen::l_get_mapgen_object(lua_State *L)
{
	const char *mgobjstr = lua_tostring(L, 1);

	int mgobjint;
	if (!string_to_enum(es_MapgenObject, mgobjint, mgobjstr ? mgobjstr : ""))
		return 0;

	enum MapgenObject mgobj = (MapgenObject)mgobjint;

	EmergeManager *emerge = getServer(L)->getEmergeManager();
	Mapgen *mg = emerge->getCurrentMapgen();
	if (!mg)
		return 0;

	size_t maplen = mg->csize.X * mg->csize.Z;

	switch (mgobj) {
	case MGOBJ_VMANIP: {
		MMVManip *vm = mg->vm;

		// VoxelManip object
		LuaVoxelManip *o = new LuaVoxelManip(vm, true);
		*(void **)(lua_newuserdata(L, sizeof(void *))) = o;
		luaL_getmetatable(L, "VoxelManip");
		lua_setmetatable(L, -2);

		// emerged min pos
		push_v3s16(L, vm->m_area.MinEdge);

		// emerged max pos
		push_v3s16(L, vm->m_area.MaxEdge);

		return 3;
	}
	case MGOBJ_HEIGHTMAP: {
		if (!mg->heightmap)
			return 0;

		lua_newtable(L);
		for (size_t i = 0; i != maplen; i++) {
			lua_pushinteger(L, mg->heightmap[i]);
			lua_rawseti(L, -2, i + 1);
		}

		return 1;
	}
	case MGOBJ_BIOMEMAP: {
		if (!mg->biomemap)
			return 0;

		lua_newtable(L);
		for (size_t i = 0; i != maplen; i++) {
			lua_pushinteger(L, mg->biomemap[i]);
			lua_rawseti(L, -2, i + 1);
		}

		return 1;
	}
	case MGOBJ_HEATMAP: { // Mapgen V7 specific objects
	case MGOBJ_HUMIDMAP:
		if (strcmp(emerge->params.mg_name.c_str(), "v7"))
			return 0;

		MapgenV7 *mgv7 = (MapgenV7 *)mg;

		float *arr = (mgobj == MGOBJ_HEATMAP) ?
			mgv7->noise_heat->result : mgv7->noise_humidity->result;
		if (!arr)
			return 0;

		lua_newtable(L);
		for (size_t i = 0; i != maplen; i++) {
			lua_pushnumber(L, arr[i]);
			lua_rawseti(L, -2, i + 1);
		}

		return 1;
	}
	case MGOBJ_GENNOTIFY: {
		std::map<std::string, std::vector<v3s16> >event_map;
		std::map<std::string, std::vector<v3s16> >::iterator it;

		mg->gennotify.getEvents(event_map);

		lua_newtable(L);
		for (it = event_map.begin(); it != event_map.end(); ++it) {
			lua_newtable(L);

			for (size_t j = 0; j != it->second.size(); j++) {
				push_v3s16(L, it->second[j]);
				lua_rawseti(L, -2, j + 1);
			}

			lua_setfield(L, -2, it->first.c_str());
		}

		return 1;
	}
	}

	return 0;
}


int ModApiMapgen::l_get_mapgen_params(lua_State *L)
{
	MapgenParams *params = &getServer(L)->getEmergeManager()->params;

	lua_newtable(L);

	lua_pushstring(L, params->mg_name.c_str());
	lua_setfield(L, -2, "mgname");

	lua_pushinteger(L, params->seed);
	lua_setfield(L, -2, "seed");

	lua_pushinteger(L, params->water_level);
	lua_setfield(L, -2, "water_level");

	lua_pushinteger(L, params->chunksize);
	lua_setfield(L, -2, "chunksize");

	std::string flagstr = writeFlagString(params->flags, flagdesc_mapgen, (u32)-1);
	lua_pushstring(L, flagstr.c_str());
	lua_setfield(L, -2, "flags");

	return 1;
}


// set_mapgen_params(params)
// set mapgen parameters
int ModApiMapgen::l_set_mapgen_params(lua_State *L)
{
	if (!lua_istable(L, 1))
		return 0;

	MapgenParams *params = &getServer(L)->getEmergeManager()->params;
	u32 flags = 0, flagmask = 0;

	lua_getfield(L, 1, "mgname");
	if (lua_isstring(L, -1)) {
		params->mg_name = lua_tostring(L, -1);
		delete params->sparams;
		params->sparams = NULL;
	}

	lua_getfield(L, 1, "seed");
	if (lua_isnumber(L, -1))
		params->seed = lua_tointeger(L, -1);

	lua_getfield(L, 1, "water_level");
	if (lua_isnumber(L, -1))
		params->water_level = lua_tointeger(L, -1);

	warn_if_field_exists(L, 1, "flagmask",
		"Deprecated: flags field now includes unset flags.");
	lua_getfield(L, 1, "flagmask");
	if (lua_isstring(L, -1))
		params->flags &= ~readFlagString(lua_tostring(L, -1), flagdesc_mapgen, NULL);

	if (getflagsfield(L, 1, "flags", flagdesc_mapgen, &flags, &flagmask)) {
		params->flags &= ~flagmask;
		params->flags |= flags;
	}

	return 0;
}


// set_noiseparams(name, noiseparams, set_default)
// set global config values for noise parameters
int ModApiMapgen::l_set_noiseparams(lua_State *L)
{
	const char *name = luaL_checkstring(L, 1);

	NoiseParams np;
	if (!read_noiseparams(L, 2, &np))
		return 0;

	bool set_default = lua_isboolean(L, 3) ? lua_toboolean(L, 3) : true;

	g_settings->setNoiseParams(name, np, set_default);

	return 0;
}


// set_gen_notify(flags, {deco_id_table})
int ModApiMapgen::l_set_gen_notify(lua_State *L)
{
	u32 flags = 0, flagmask = 0;
	EmergeManager *emerge = getServer(L)->getEmergeManager();

	if (read_flags(L, 1, flagdesc_gennotify, &flags, &flagmask)) {
		emerge->gen_notify_on &= ~flagmask;
		emerge->gen_notify_on |= flags;
	}

	if (lua_istable(L, 2)) {
		lua_pushnil(L);
		while (lua_next(L, 2)) {
			if (lua_isnumber(L, -1))
				emerge->gen_notify_on_deco_ids.insert(lua_tonumber(L, -1));
			lua_pop(L, 1);
		}
	}

	return 0;
}


// register_biome({lots of stuff})
int ModApiMapgen::l_register_biome(lua_State *L)
{
	int index = 1;
	luaL_checktype(L, index, LUA_TTABLE);

	INodeDefManager *ndef = getServer(L)->getNodeDefManager();
	BiomeManager *bmgr    = getServer(L)->getEmergeManager()->biomemgr;

	Biome *biome = read_biome_def(L, index, ndef);
	if (!biome)
		return 0;

	ObjDefHandle handle = bmgr->add(biome);
	if (handle == OBJDEF_INVALID_HANDLE) {
		delete biome;
		return 0;
	}

	lua_pushinteger(L, handle);
	return 1;
}


// register_decoration({lots of stuff})
int ModApiMapgen::l_register_decoration(lua_State *L)
{
	int index = 1;
	luaL_checktype(L, index, LUA_TTABLE);

	INodeDefManager *ndef      = getServer(L)->getNodeDefManager();
	DecorationManager *decomgr = getServer(L)->getEmergeManager()->decomgr;
	BiomeManager *biomemgr     = getServer(L)->getEmergeManager()->biomemgr;
	SchematicManager *schemmgr = getServer(L)->getEmergeManager()->schemmgr;

	enum DecorationType decotype = (DecorationType)getenumfield(L, index,
				"deco_type", es_DecorationType, -1);

	Decoration *deco = decomgr->create(decotype);
	if (!deco) {
		errorstream << "register_decoration: decoration placement type "
			<< decotype << " not implemented" << std::endl;
		return 0;
	}

	deco->name       = getstringfield_default(L, index, "name", "");
	deco->fill_ratio = getfloatfield_default(L, index, "fill_ratio", 0.02);
	deco->y_min      = getintfield_default(L, index, "y_min", -31000);
	deco->y_max      = getintfield_default(L, index, "y_max", 31000);
	deco->sidelen    = getintfield_default(L, index, "sidelen", 8);
	if (deco->sidelen <= 0) {
		errorstream << "register_decoration: sidelen must be "
			"greater than 0" << std::endl;
		delete deco;
		return 0;
	}

	NodeResolveInfo *nri = new NodeResolveInfo(deco);

	//// Get node name(s) to place decoration on
	std::vector<const char *> place_on_names;
	getstringlistfield(L, index, "place_on", place_on_names);
	nri->nodelistinfo.push_back(NodeListInfo(place_on_names.size()));
	for (size_t i = 0; i != place_on_names.size(); i++)
		nri->nodenames.push_back(place_on_names[i]);

	getflagsfield(L, index, "flags", flagdesc_deco, &deco->flags, NULL);

	//// Get NoiseParams to define how decoration is placed
	lua_getfield(L, index, "noise_params");
	if (read_noiseparams(L, -1, &deco->np))
		deco->flags |= DECO_USE_NOISE;
	lua_pop(L, 1);

	//// Get biomes associated with this decoration (if any)
	lua_getfield(L, index, "biomes");
	if (get_biome_list(L, -1, biomemgr, &deco->biomes))
		errorstream << "register_decoration: couldn't get all biomes " << std::endl;
	lua_pop(L, 1);

	//// Handle decoration type-specific parameters
	bool success = false;
	switch (decotype) {
	case DECO_SIMPLE:
		success = read_deco_simple(L, nri, (DecoSimple *)deco);
		break;
	case DECO_SCHEMATIC:
		success = read_deco_schematic(L, schemmgr, (DecoSchematic *)deco);
		break;
	case DECO_LSYSTEM:
		break;
	}

	ndef->pendNodeResolve(nri);

	if (!success) {
		delete deco;
		return 0;
	}

	ObjDefHandle handle = decomgr->add(deco);
	if (handle == OBJDEF_INVALID_HANDLE) {
		delete deco;
		return 0;
	}

	lua_pushinteger(L, handle);
	return 1;
}


bool read_deco_simple(lua_State *L, NodeResolveInfo *nri, DecoSimple *deco)
{
	int index = 1;

	deco->deco_height     = getintfield_default(L, index, "height", 1);
	deco->deco_height_max = getintfield_default(L, index, "height_max", 0);
	deco->nspawnby        = getintfield_default(L, index, "num_spawn_by", -1);

	if (deco->deco_height <= 0) {
		errorstream << "register_decoration: simple decoration height"
			" must be greater than 0" << std::endl;
		return false;
	}

	std::vector<const char *> deco_names;
	getstringlistfield(L, index, "decoration", deco_names);
	if (deco_names.size() == 0) {
		errorstream << "register_decoration: no decoration nodes "
			"defined" << std::endl;
		return false;
	}
	nri->nodelistinfo.push_back(NodeListInfo(deco_names.size()));
	for (size_t i = 0; i != deco_names.size(); i++)
		nri->nodenames.push_back(deco_names[i]);

	std::vector<const char *> spawnby_names;
	getstringlistfield(L, index, "spawn_by", spawnby_names);
	if (deco->nspawnby != -1 && spawnby_names.size() == 0) {
		errorstream << "register_decoration: no spawn_by nodes defined,"
			" but num_spawn_by specified" << std::endl;
		return false;
	}
	nri->nodelistinfo.push_back(NodeListInfo(spawnby_names.size()));
	for (size_t i = 0; i != spawnby_names.size(); i++)
		nri->nodenames.push_back(spawnby_names[i]);

	return true;
}


bool read_deco_schematic(lua_State *L, SchematicManager *schemmgr, DecoSchematic *deco)
{
	int index = 1;

	deco->rotation = (Rotation)getenumfield(L, index, "rotation",
		ModApiMapgen::es_Rotation, ROTATE_0);

	StringMap replace_names;
	lua_getfield(L, index, "replacements");
	if (lua_istable(L, -1))
		read_schematic_replacements(L, -1, &replace_names);
	lua_pop(L, 1);

	lua_getfield(L, index, "schematic");
	Schematic *schem = get_or_load_schematic(L, -1, schemmgr, &replace_names);
	lua_pop(L, 1);

	deco->schematic = schem;
	return schem != NULL;
}


// register_ore({lots of stuff})
int ModApiMapgen::l_register_ore(lua_State *L)
{
	int index = 1;
	luaL_checktype(L, index, LUA_TTABLE);

	INodeDefManager *ndef = getServer(L)->getNodeDefManager();
	OreManager *oremgr    = getServer(L)->getEmergeManager()->oremgr;

	enum OreType oretype = (OreType)getenumfield(L, index,
				"ore_type", es_OreType, ORE_SCATTER);
	Ore *ore = oremgr->create(oretype);
	if (!ore) {
		errorstream << "register_ore: ore_type " << oretype << " not implemented";
		return 0;
	}

	ore->name           = getstringfield_default(L, index, "name", "");
	ore->ore_param2     = (u8)getintfield_default(L, index, "ore_param2", 0);
	ore->clust_scarcity = getintfield_default(L, index, "clust_scarcity", 1);
	ore->clust_num_ores = getintfield_default(L, index, "clust_num_ores", 1);
	ore->clust_size     = getintfield_default(L, index, "clust_size", 0);
	ore->nthresh        = getfloatfield_default(L, index, "noise_threshhold", 0);
	ore->noise          = NULL;
	ore->flags          = 0;

	warn_if_field_exists(L, index, "height_min",
		"Deprecated: new name is \"y_min\".");
	warn_if_field_exists(L, index, "height_max",
		"Deprecated: new name is \"y_max\".");

	int ymin, ymax;
	if (!getintfield(L, index, "y_min", ymin) &&
		!getintfield(L, index, "height_min", ymin))
		ymin = -31000;
	if (!getintfield(L, index, "y_max", ymax) &&
		!getintfield(L, index, "height_max", ymax))
		ymax = 31000;
	ore->y_min = ymin;
	ore->y_max = ymax;

	if (ore->clust_scarcity <= 0 || ore->clust_num_ores <= 0) {
		errorstream << "register_ore: clust_scarcity and clust_num_ores"
			"must be greater than 0" << std::endl;
		delete ore;
		return 0;
	}

	getflagsfield(L, index, "flags", flagdesc_ore, &ore->flags, NULL);

	lua_getfield(L, index, "noise_params");
	if (read_noiseparams(L, -1, &ore->np)) {
		ore->flags |= OREFLAG_USE_NOISE;
	} else if (ore->NEEDS_NOISE) {
		errorstream << "register_ore: specified ore type requires valid "
			"noise parameters" << std::endl;
		delete ore;
		return 0;
	}
	lua_pop(L, 1);

	if (oretype == ORE_VEIN) {
		OreVein *orevein = (OreVein *)ore;
		orevein->random_factor = getfloatfield_default(L, index,
			"random_factor", 1.f);
	}

	ObjDefHandle handle = oremgr->add(ore);
	if (handle == OBJDEF_INVALID_HANDLE) {
		delete ore;
		return 0;
	}

	NodeResolveInfo *nri = new NodeResolveInfo(ore);
	nri->nodenames.push_back(getstringfield_default(L, index, "ore", ""));

	std::vector<const char *> wherein_names;
	getstringlistfield(L, index, "wherein", wherein_names);
	nri->nodelistinfo.push_back(NodeListInfo(wherein_names.size()));
	for (size_t i = 0; i != wherein_names.size(); i++)
		nri->nodenames.push_back(wherein_names[i]);

	ndef->pendNodeResolve(nri);

	lua_pushinteger(L, handle);
	return 1;
}


// register_schematic({schematic}, replacements={})
int ModApiMapgen::l_register_schematic(lua_State *L)
{
	SchematicManager *schemmgr = getServer(L)->getEmergeManager()->schemmgr;

	StringMap replace_names;
	if (lua_istable(L, 2))
		read_schematic_replacements(L, 2, &replace_names);

	Schematic *schem = load_schematic(L, 1, schemmgr, &replace_names);
	if (!schem)
		return 0;

	ObjDefHandle handle = schemmgr->add(schem);
	if (handle == OBJDEF_INVALID_HANDLE) {
		delete schem;
		return 0;
	}

	lua_pushinteger(L, handle);
	return 1;
}


// clear_registered_biomes()
int ModApiMapgen::l_clear_registered_biomes(lua_State *L)
{
	BiomeManager *bmgr = getServer(L)->getEmergeManager()->biomemgr;
	bmgr->clear();
	return 0;
}


// clear_registered_decorations()
int ModApiMapgen::l_clear_registered_decorations(lua_State *L)
{
	DecorationManager *dmgr = getServer(L)->getEmergeManager()->decomgr;
	dmgr->clear();
	return 0;
}


// clear_registered_ores()
int ModApiMapgen::l_clear_registered_ores(lua_State *L)
{
	OreManager *omgr = getServer(L)->getEmergeManager()->oremgr;
	omgr->clear();
	return 0;
}


// clear_registered_schematics()
int ModApiMapgen::l_clear_registered_schematics(lua_State *L)
{
	SchematicManager *smgr = getServer(L)->getEmergeManager()->schemmgr;
	smgr->clear();
	return 0;
}


// generate_ores(vm, p1, p2, [ore_id])
int ModApiMapgen::l_generate_ores(lua_State *L)
{
	EmergeManager *emerge = getServer(L)->getEmergeManager();

	Mapgen mg;
	mg.seed = emerge->params.seed;
	mg.vm   = LuaVoxelManip::checkobject(L, 1)->vm;
	mg.ndef = getServer(L)->getNodeDefManager();

	v3s16 pmin = lua_istable(L, 2) ? read_v3s16(L, 2) :
			mg.vm->m_area.MinEdge + v3s16(1,1,1) * MAP_BLOCKSIZE;
	v3s16 pmax = lua_istable(L, 3) ? read_v3s16(L, 3) :
			mg.vm->m_area.MaxEdge - v3s16(1,1,1) * MAP_BLOCKSIZE;
	sortBoxVerticies(pmin, pmax);

	u32 blockseed = Mapgen::getBlockSeed(pmin, mg.seed);

	emerge->oremgr->placeAllOres(&mg, blockseed, pmin, pmax);

	return 0;
}


// generate_decorations(vm, p1, p2, [deco_id])
int ModApiMapgen::l_generate_decorations(lua_State *L)
{
	EmergeManager *emerge = getServer(L)->getEmergeManager();

	Mapgen mg;
	mg.seed = emerge->params.seed;
	mg.vm   = LuaVoxelManip::checkobject(L, 1)->vm;
	mg.ndef = getServer(L)->getNodeDefManager();

	v3s16 pmin = lua_istable(L, 2) ? read_v3s16(L, 2) :
			mg.vm->m_area.MinEdge + v3s16(1,1,1) * MAP_BLOCKSIZE;
	v3s16 pmax = lua_istable(L, 3) ? read_v3s16(L, 3) :
			mg.vm->m_area.MaxEdge - v3s16(1,1,1) * MAP_BLOCKSIZE;
	sortBoxVerticies(pmin, pmax);

	u32 blockseed = Mapgen::getBlockSeed(pmin, mg.seed);

	emerge->decomgr->placeAllDecos(&mg, blockseed, pmin, pmax);

	return 0;
}


// create_schematic(p1, p2, probability_list, filename, y_slice_prob_list)
int ModApiMapgen::l_create_schematic(lua_State *L)
{
	Schematic schem;

	Map *map = &(getEnv(L)->getMap());
	INodeDefManager *ndef = getServer(L)->getNodeDefManager();

	v3s16 p1 = read_v3s16(L, 1);
	v3s16 p2 = read_v3s16(L, 2);
	sortBoxVerticies(p1, p2);

	std::vector<std::pair<v3s16, u8> > prob_list;
	if (lua_istable(L, 3)) {
		lua_pushnil(L);
		while (lua_next(L, 3)) {
			if (lua_istable(L, -1)) {
				lua_getfield(L, -1, "pos");
				v3s16 pos = read_v3s16(L, -1);
				lua_pop(L, 1);

				u8 prob = getintfield_default(L, -1, "prob", MTSCHEM_PROB_ALWAYS);
				prob_list.push_back(std::make_pair(pos, prob));
			}

			lua_pop(L, 1);
		}
	}

	std::vector<std::pair<s16, u8> > slice_prob_list;
	if (lua_istable(L, 5)) {
		lua_pushnil(L);
		while (lua_next(L, 5)) {
			if (lua_istable(L, -1)) {
				s16 ypos = getintfield_default(L, -1, "ypos", 0);
				u8 prob  = getintfield_default(L, -1, "prob", MTSCHEM_PROB_ALWAYS);
				slice_prob_list.push_back(std::make_pair(ypos, prob));
			}

			lua_pop(L, 1);
		}
	}

	const char *filename = luaL_checkstring(L, 4);

	if (!schem.getSchematicFromMap(map, p1, p2)) {
		errorstream << "create_schematic: failed to get schematic "
			"from map" << std::endl;
		return 0;
	}

	schem.applyProbabilities(p1, &prob_list, &slice_prob_list);

	schem.saveSchematicToFile(filename, ndef);
	actionstream << "create_schematic: saved schematic file '"
		<< filename << "'." << std::endl;

	lua_pushboolean(L, true);
	return 1;
}


// place_schematic(p, schematic, rotation, replacement)
int ModApiMapgen::l_place_schematic(lua_State *L)
{
	Map *map = &(getEnv(L)->getMap());
	SchematicManager *schemmgr = getServer(L)->getEmergeManager()->schemmgr;

	//// Read position
	v3s16 p = read_v3s16(L, 1);

	//// Read rotation
	int rot = ROTATE_0;
	if (lua_isstring(L, 3))
		string_to_enum(es_Rotation, rot, std::string(lua_tostring(L, 3)));

	//// Read force placement
	bool force_placement = true;
	if (lua_isboolean(L, 5))
		force_placement = lua_toboolean(L, 5);

	//// Read node replacements
	StringMap replace_names;
	if (lua_istable(L, 4))
		read_schematic_replacements(L, 4, &replace_names);

	//// Read schematic
	Schematic *schem = get_or_load_schematic(L, 2, schemmgr, &replace_names);
	if (!schem) {
		errorstream << "place_schematic: failed to get schematic" << std::endl;
		return 0;
	}

	schem->placeStructure(map, p, 0, (Rotation)rot, force_placement,
		schemmgr->getNodeDef());

	lua_pushboolean(L, true);
	return 1;
}


void ModApiMapgen::Initialize(lua_State *L, int top)
{
	API_FCT(get_mapgen_object);

	API_FCT(get_mapgen_params);
	API_FCT(set_mapgen_params);
	API_FCT(set_noiseparams);
	API_FCT(set_gen_notify);

	API_FCT(register_biome);
	API_FCT(register_decoration);
	API_FCT(register_ore);
	API_FCT(register_schematic);

	API_FCT(clear_registered_biomes);
	API_FCT(clear_registered_decorations);
	API_FCT(clear_registered_ores);
	API_FCT(clear_registered_schematics);

	API_FCT(generate_ores);
	API_FCT(generate_decorations);
	API_FCT(create_schematic);
	API_FCT(place_schematic);
}