Add MapSettingsManager and new mapgen setting script API functions

This commit refactors the majority of the Mapgen settings system.
- MapgenParams is now owned by MapSettingsManager, itself a part of ServerMap,
  instead of the EmergeManager.
- New Script API functions added:
    core.get_mapgen_setting
    core.get_mapgen_setting_noiseparams,
    core.set_mapgen_setting, and
    core.set_mapgen_setting_noiseparams.
- minetest.get/set_mapgen_params are deprecated by the above new functions.
- It is now possible to view and modify any arbitrary mapgen setting from a mod,
  rather than the base MapgenParams structure.
- MapgenSpecificParams has been removed.

build/android/jni/Android.mk

@@ -169,6 +169,7 @@ LOCAL_SRC_FILES := \
 		jni/src/log.cpp                           \
 		jni/src/main.cpp                          \
 		jni/src/map.cpp                           \
+		jni/src/map_settings_manager.cpp          \
 		jni/src/mapblock.cpp                      \
 		jni/src/mapblock_mesh.cpp                 \
 		jni/src/mapgen.cpp                        \
@@ -238,6 +239,7 @@ LOCAL_SRC_FILES := \
 		jni/src/unittest/test_connection.cpp      \
 		jni/src/unittest/test_filepath.cpp        \
 		jni/src/unittest/test_inventory.cpp       \
+		jni/src/unittest/test_map_settings_manager.cpp \
 		jni/src/unittest/test_mapnode.cpp         \
 		jni/src/unittest/test_nodedef.cpp         \
 		jni/src/unittest/test_noderesolver.cpp    \

doc/lua_api.txt

@@ -2089,7 +2089,9 @@ and `minetest.auth_reload` call the authetification handler.
       given biome_name string.
 * `minetest.get_mapgen_params()` Returns mapgen parameters, a table containing
   `mgname`, `seed`, `chunksize`, `water_level`, and `flags`.
+  * Deprecated: use minetest.get_mapgen_setting(name) instead
 * `minetest.set_mapgen_params(MapgenParams)`
+    * Deprecated: use minetest.set_mapgen_setting(name, value, override) instead
     * Set map generation parameters
     * Function cannot be called after the registration period; only initialization
       and `on_mapgen_init`
@@ -2099,6 +2101,23 @@ and `minetest.auth_reload` call the authetification handler.
         * `flags` contains a comma-delimited string of flags to set,
           or if the prefix `"no"` is attached, clears instead.
         * `flags` is in the same format and has the same options as `mg_flags` in `minetest.conf`
+* `minetest.get_mapgen_setting(name)`
+    * Gets the *active* mapgen setting (or nil if none exists) in string format with the following
+      order of precedence:
+        1) Settings loaded from map_meta.txt or overrides set during mod execution
+        2) Settings set by mods without a metafile override
+        3) Settings explicitly set in the user config file, minetest.conf
+        4) Settings set as the user config default
+* `minetest.get_mapgen_setting_noiseparams(name)`
+    * Same as above, but returns the value as a NoiseParams table if the setting `name` exists
+      and is a valid NoiseParams
+* `minetest.set_mapgen_setting(name, value, [override_meta=false])`
+   * Sets a mapgen param to `value`, and will take effect if the corresponding mapgen setting
+     is not already present in map_meta.txt.  If the optional boolean override_meta is set to true,
+     this setting will become the active setting regardless of the map metafile contents.
+   * Note: to set the seed, use "seed", not "fixed_map_seed"
+* `minetest.set_mapgen_setting_noiseparams(name, value, [override_meta=false])`
+   * Same as above, except value is a NoiseParams table
 * `minetest.set_noiseparams(name, noiseparams, set_default)`
     * Sets the noiseparams setting of `name` to the noiseparams table specified in `noiseparams`.
     * `set_default` is an optional boolean (default: `true`) that specifies whether the setting

src/CMakeLists.txt

@@ -414,6 +414,7 @@ set(common_SRCS
 	light.cpp
 	log.cpp
 	map.cpp
+	map_settings_manager.cpp
 	mapblock.cpp
 	mapgen.cpp
 	mapgen_flat.cpp

src/emerge.cpp

@@ -156,37 +156,19 @@ EmergeManager::~EmergeManager()
 }
 
 
-void EmergeManager::loadMapgenParams()
+bool EmergeManager::initMapgens(MapgenParams *params)
-{
-	params.load(*g_settings);
-}
-
-
-void EmergeManager::initMapgens()
 {
 	if (m_mapgens.size())
-		return;
+		return false;
 
-	MapgenType mgtype = Mapgen::getMapgenType(params.mg_name);
+	this->mgparams = params;
-	if (mgtype == MAPGEN_INVALID) {
-		const char *default_mapgen_name = Mapgen::getMapgenName(MAPGEN_DEFAULT);
-		errorstream << "EmergeManager: mapgen " << params.mg_name <<
-			" not registered; falling back to " <<
-			default_mapgen_name << std::endl;
-
-		params.mg_name = default_mapgen_name;
-		mgtype = MAPGEN_DEFAULT;
-	}
-
-	if (!params.sparams) {
-		params.sparams = Mapgen::createMapgenParams(mgtype);
-		params.sparams->readParams(g_settings);
-	}
 
 	for (u32 i = 0; i != m_threads.size(); i++) {
-		Mapgen *mg = Mapgen::createMapgen(mgtype, i, &params, this);
+		Mapgen *mg = Mapgen::createMapgen(params->mgtype, i, params, this);
 		m_mapgens.push_back(mg);
 	}
+
+	return true;
 }
 
 
@@ -288,12 +270,14 @@ bool EmergeManager::enqueueBlockEmergeEx(
 // Mapgen-related helper functions
 //
 
+
+// TODO(hmmmm): Move this to ServerMap
 v3s16 EmergeManager::getContainingChunk(v3s16 blockpos)
 {
-	return getContainingChunk(blockpos, params.chunksize);
+	return getContainingChunk(blockpos, mgparams->chunksize);
 }
 
-
+// TODO(hmmmm): Move this to ServerMap
 v3s16 EmergeManager::getContainingChunk(v3s16 blockpos, s16 chunksize)
 {
 	s16 coff = -chunksize / 2;
@@ -327,7 +311,7 @@ int EmergeManager::getGroundLevelAtPoint(v2s16 p)
 	return m_mapgens[0]->getGroundLevelAtPoint(p);
 }
 
-
+// TODO(hmmmm): Move this to ServerMap
 bool EmergeManager::isBlockUnderground(v3s16 blockpos)
 {
 #if 0
@@ -338,7 +322,7 @@ bool EmergeManager::isBlockUnderground(v3s16 blockpos)
 #endif
 
 	// Use a simple heuristic; the above method is wildly inaccurate anyway.
-	return blockpos.Y * (MAP_BLOCKSIZE + 1) <= params.water_level;
+	return blockpos.Y * (MAP_BLOCKSIZE + 1) <= mgparams->water_level;
 }
 
 bool EmergeManager::pushBlockEmergeData(

src/emerge.h

@@ -97,8 +97,16 @@ public:
 	u32 gen_notify_on;
 	std::set<u32> gen_notify_on_deco_ids;
 
-	// Map generation parameters
+	// Parameters passed to mapgens owned by ServerMap
-	MapgenParams params;
+	// TODO(hmmmm): Remove this after mapgen helper methods using them
+	// are moved to ServerMap
+	MapgenParams *mgparams;
+
+	// Hackish workaround:
+	// For now, EmergeManager must hold onto a ptr to the Map's setting manager
+	// since the Map can only be accessed through the Environment, and the
+	// Environment is not created until after script initialization.
+	MapSettingsManager *map_settings_mgr;
 
 	// Managers of various map generation-related components
 	BiomeManager *biomemgr;
@@ -110,8 +118,7 @@ public:
 	EmergeManager(IGameDef *gamedef);
 	~EmergeManager();
 
-	void loadMapgenParams();
+	bool initMapgens(MapgenParams *mgparams);
-	void initMapgens();
 
 	void startThreads();
 	void stopThreads();

src/map.cpp

@@ -2130,11 +2130,15 @@ void Map::removeNodeTimer(v3s16 p)
 */
 ServerMap::ServerMap(std::string savedir, IGameDef *gamedef, EmergeManager *emerge):
 	Map(dout_server, gamedef),
+	settings_mgr(g_settings, savedir + DIR_DELIM + "map_meta.txt"),
 	m_emerge(emerge),
 	m_map_metadata_changed(true)
 {
 	verbosestream<<FUNCTION_NAME<<std::endl;
 
+	// Tell the EmergeManager about our MapSettingsManager
+	emerge->map_settings_mgr = &settings_mgr;
+
 	/*
 		Try to load map; if not found, create a new one.
 	*/
@@ -2170,26 +2174,15 @@ ServerMap::ServerMap(std::string savedir, IGameDef *gamedef, EmergeManager *emer
 			}
 			else
 			{
-				try{
-					// Load map metadata (seed, chunksize)
-					loadMapMeta();
-				}
-				catch(SettingNotFoundException &e){
-					infostream<<"ServerMap:  Some metadata not found."
-							  <<" Using default settings."<<std::endl;
-				}
-				catch(FileNotGoodException &e){
-					warningstream<<"Could not load map metadata"
-							//<<" Disabling chunk-based generator."
-							<<std::endl;
-					//m_chunksize = 0;
-				}
 
-				infostream<<"ServerMap: Successfully loaded map "
+				if (settings_mgr.loadMapMeta()) {
-						<<"metadata from "<<savedir
+					infostream << "ServerMap: Metadata loaded from "
-						<<", assuming valid save directory."
+						<< savedir << std::endl;
-						<<" seed="<< m_emerge->params.seed <<"."
+				} else {
-						<<std::endl;
+					infostream << "ServerMap: Metadata could not be loaded "
+						"from " << savedir << ", assuming valid save "
+						"directory." << std::endl;
+				}
 
 				m_map_saving_enabled = true;
 				// Map loaded, not creating new one
@@ -2259,19 +2252,26 @@ ServerMap::~ServerMap()
 #endif
 }
 
+MapgenParams *ServerMap::getMapgenParams()
+{
+	// getMapgenParams() should only ever be called after Server is initialized
+	assert(settings_mgr.mapgen_params != NULL);
+	return settings_mgr.mapgen_params;
+}
+
 u64 ServerMap::getSeed()
 {
-	return m_emerge->params.seed;
+	return getMapgenParams()->seed;
 }
 
 s16 ServerMap::getWaterLevel()
 {
-	return m_emerge->params.water_level;
+	return getMapgenParams()->water_level;
 }
 
 bool ServerMap::initBlockMake(v3s16 blockpos, BlockMakeData *data)
 {
-	s16 csize = m_emerge->params.chunksize;
+	s16 csize = getMapgenParams()->chunksize;
 	v3s16 bpmin = EmergeManager::getContainingChunk(blockpos, csize);
 	v3s16 bpmax = bpmin + v3s16(1, 1, 1) * (csize - 1);
 
@@ -2287,7 +2287,7 @@ bool ServerMap::initBlockMake(v3s16 blockpos, BlockMakeData *data)
 		blockpos_over_limit(full_bpmax))
 		return false;
 
-	data->seed = m_emerge->params.seed;
+	data->seed = getSeed();
 	data->blockpos_min = bpmin;
 	data->blockpos_max = bpmax;
 	data->blockpos_requested = blockpos;
@@ -2905,8 +2905,9 @@ void ServerMap::save(ModifiedState save_level)
 		infostream<<"ServerMap: Saving whole map, this can take time."
 				<<std::endl;
 
-	if(m_map_metadata_changed || save_level == MOD_STATE_CLEAN) {
+	if (m_map_metadata_changed || save_level == MOD_STATE_CLEAN) {
-		saveMapMeta();
+		if (settings_mgr.saveMapMeta())
+			m_map_metadata_changed = false;
 	}
 
 	// Profile modified reasons
@@ -3005,55 +3006,6 @@ void ServerMap::listAllLoadedBlocks(std::vector<v3s16> &dst)
 	}
 }
 
-void ServerMap::saveMapMeta()
-{
-	DSTACK(FUNCTION_NAME);
-
-	createDirs(m_savedir);
-
-	std::string fullpath = m_savedir + DIR_DELIM + "map_meta.txt";
-	std::ostringstream oss(std::ios_base::binary);
-	Settings conf;
-
-	m_emerge->params.save(conf);
-	conf.writeLines(oss);
-
-	oss << "[end_of_params]\n";
-
-	if(!fs::safeWriteToFile(fullpath, oss.str())) {
-		errorstream << "ServerMap::saveMapMeta(): "
-				<< "could not write " << fullpath << std::endl;
-		throw FileNotGoodException("Cannot save chunk metadata");
-	}
-
-	m_map_metadata_changed = false;
-}
-
-void ServerMap::loadMapMeta()
-{
-	DSTACK(FUNCTION_NAME);
-
-	Settings conf;
-	std::string fullpath = m_savedir + DIR_DELIM + "map_meta.txt";
-
-	std::ifstream is(fullpath.c_str(), std::ios_base::binary);
-	if (!is.good()) {
-		errorstream << "ServerMap::loadMapMeta(): "
-			"could not open " << fullpath << std::endl;
-		throw FileNotGoodException("Cannot open map metadata");
-	}
-
-	if (!conf.parseConfigLines(is, "[end_of_params]")) {
-		throw SerializationError("ServerMap::loadMapMeta(): "
-				"[end_of_params] not found!");
-	}
-
-	m_emerge->params.load(conf);
-
-	verbosestream << "ServerMap::loadMapMeta(): seed="
-		<< m_emerge->params.seed << std::endl;
-}
-
 void ServerMap::saveSectorMeta(ServerMapSector *sector)
 {
 	DSTACK(FUNCTION_NAME);

src/map.h

@@ -33,6 +33,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "modifiedstate.h"
 #include "util/container.h"
 #include "nodetimer.h"
+#include "map_settings_manager.h"
 
 class Settings;
 class Database;
@@ -46,8 +47,6 @@ class IRollbackManager;
 class EmergeManager;
 class ServerEnvironment;
 struct BlockMakeData;
-struct MapgenParams;
-
 
 /*
 	MapEditEvent
@@ -463,9 +462,8 @@ public:
 	void save(ModifiedState save_level);
 	void listAllLoadableBlocks(std::vector<v3s16> &dst);
 	void listAllLoadedBlocks(std::vector<v3s16> &dst);
-	// Saves map seed and possibly other stuff
+
-	void saveMapMeta();
+	MapgenParams *getMapgenParams();
-	void loadMapMeta();
 
 	/*void saveChunkMeta();
 	void loadChunkMeta();*/
@@ -506,6 +504,8 @@ public:
 	u64 getSeed();
 	s16 getWaterLevel();
 
+	MapSettingsManager settings_mgr;
+
 private:
 	// Emerge manager
 	EmergeManager *m_emerge;

src/map_settings_manager.cpp

@@ -0,0 +1,194 @@
+/*
+Minetest
+Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
+
+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 "debug.h"
+#include "filesys.h"
+#include "log.h"
+#include "mapgen.h"
+#include "settings.h"
+
+#include "map_settings_manager.h"
+
+MapSettingsManager::MapSettingsManager(
+	Settings *user_settings, const std::string &map_meta_path)
+{
+	m_map_meta_path = map_meta_path;
+	m_user_settings = user_settings;
+	m_map_settings  = new Settings;
+	mapgen_params   = NULL;
+
+	assert(m_user_settings != NULL);
+}
+
+
+MapSettingsManager::~MapSettingsManager()
+{
+	delete m_map_settings;
+	delete mapgen_params;
+}
+
+
+bool MapSettingsManager::getMapSetting(
+	const std::string &name, std::string *value_out)
+{
+	if (m_map_settings->getNoEx(name, *value_out))
+		return true;
+
+	// Compatibility kludge
+	if (m_user_settings == g_settings && name == "seed")
+		return m_user_settings->getNoEx("fixed_map_seed", *value_out);
+
+	return m_user_settings->getNoEx(name, *value_out);
+}
+
+
+bool MapSettingsManager::getMapSettingNoiseParams(
+	const std::string &name, NoiseParams *value_out)
+{
+	return m_map_settings->getNoiseParams(name, *value_out) ||
+		m_user_settings->getNoiseParams(name, *value_out);
+}
+
+
+bool MapSettingsManager::setMapSetting(
+	const std::string &name, const std::string &value, bool override_meta)
+{
+	if (mapgen_params)
+		return false;
+
+	if (override_meta)
+		m_map_settings->set(name, value);
+	else
+		m_map_settings->setDefault(name, value);
+
+	return true;
+}
+
+
+bool MapSettingsManager::setMapSettingNoiseParams(
+	const std::string &name, const NoiseParams *value, bool override_meta)
+{
+	if (mapgen_params)
+		return false;
+
+	m_map_settings->setNoiseParams(name, *value, !override_meta);
+	return true;
+}
+
+
+bool MapSettingsManager::loadMapMeta()
+{
+	std::ifstream is(m_map_meta_path.c_str(), std::ios_base::binary);
+
+	if (!is.good()) {
+		errorstream << "loadMapMeta: could not open "
+			<< m_map_meta_path << std::endl;
+		return false;
+	}
+
+	if (!m_map_settings->parseConfigLines(is, "[end_of_params]")) {
+		errorstream << "loadMapMeta: [end_of_params] not found!" << std::endl;
+		return false;
+	}
+
+	return true;
+}
+
+
+bool MapSettingsManager::saveMapMeta()
+{
+	// If mapgen params haven't been created yet; abort
+	if (!mapgen_params)
+		return false;
+
+	if (!fs::CreateAllDirs(fs::RemoveLastPathComponent(m_map_meta_path))) {
+		errorstream << "saveMapMeta: could not create dirs to "
+			<< m_map_meta_path;
+		return false;
+	}
+
+	std::ostringstream oss(std::ios_base::binary);
+	Settings conf;
+
+	mapgen_params->MapgenParams::writeParams(&conf);
+	mapgen_params->writeParams(&conf);
+	conf.writeLines(oss);
+
+	// NOTE: If there are ever types of map settings other than
+	// those relating to map generation, save them here
+
+	oss << "[end_of_params]\n";
+
+	if (!fs::safeWriteToFile(m_map_meta_path, oss.str())) {
+		errorstream << "saveMapMeta: could not write "
+			<< m_map_meta_path << std::endl;
+		return false;
+	}
+
+	return true;
+}
+
+
+MapgenParams *MapSettingsManager::makeMapgenParams()
+{
+	if (mapgen_params)
+		return mapgen_params;
+
+	assert(m_user_settings != NULL);
+	assert(m_map_settings != NULL);
+
+	// At this point, we have (in order of precedence):
+	// 1). m_mapgen_settings->m_settings containing map_meta.txt settings or
+	//     explicit overrides from scripts
+	// 2). m_mapgen_settings->m_defaults containing script-set mgparams without
+	//     overrides
+	// 3). g_settings->m_settings containing all user-specified config file
+	//     settings
+	// 4). g_settings->m_defaults containing any low-priority settings from
+	//     scripts, e.g. mods using Lua as an enhanced config file)
+
+	// Now, get the mapgen type so we can create the appropriate MapgenParams
+	std::string mg_name;
+	MapgenType mgtype = getMapSetting("mg_name", &mg_name) ?
+		Mapgen::getMapgenType(mg_name) : MAPGEN_DEFAULT;
+	if (mgtype == MAPGEN_INVALID) {
+		errorstream << "EmergeManager: mapgen '" << mg_name <<
+			"' not valid; falling back to " <<
+			Mapgen::getMapgenName(MAPGEN_DEFAULT) << std::endl;
+		mgtype = MAPGEN_DEFAULT;
+	}
+
+	// Create our MapgenParams
+	MapgenParams *params = Mapgen::createMapgenParams(mgtype);
+	if (params == NULL)
+		return NULL;
+
+	params->mgtype = mgtype;
+
+	// Load the rest of the mapgen params from our active settings
+	params->MapgenParams::readParams(m_user_settings);
+	params->MapgenParams::readParams(m_map_settings);
+	params->readParams(m_user_settings);
+	params->readParams(m_map_settings);
+
+	// Hold onto our params
+	mapgen_params = params;
+
+	return params;
+}

src/map_settings_manager.h

@@ -0,0 +1,79 @@
+/*
+Minetest
+Copyright (C) 2010-2013 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#ifndef MAP_SETTINGS_MANAGER_HEADER
+#define MAP_SETTINGS_MANAGER_HEADER
+
+#include <string>
+
+class Settings;
+struct NoiseParams;
+struct MapgenParams;
+
+/*
+	MapSettingsManager is a centralized object for management (creating,
+	loading, storing, saving, etc.) of config settings related to the Map.
+
+	It has two phases: the initial r/w "gather and modify settings" state, and
+	the final r/o "read and save settings" state.
+
+	The typical use case is, in order, as follows:
+	- Create a MapSettingsManager object
+	- Try to load map metadata into it from the metadata file
+	- Manually view and modify the current configuration as desired through a
+	  Settings-like interface
+	- When all modifications are finished, create a 'Parameters' object
+	  containing the finalized, active parameters.  This could be passed along
+	  to whichever Map-related objects that may require it.
+	- Save these active settings to the metadata file when requested
+*/
+class MapSettingsManager {
+public:
+	// Finalized map generation parameters
+	MapgenParams *mapgen_params;
+
+	MapSettingsManager(Settings *user_settings,
+		const std::string &map_meta_path);
+	~MapSettingsManager();
+
+	bool getMapSetting(const std::string &name, std::string *value_out);
+
+	bool getMapSettingNoiseParams(
+		const std::string &name, NoiseParams *value_out);
+
+	// Note: Map config becomes read-only after makeMapgenParams() gets called
+	// (i.e. mapgen_params is non-NULL).  Attempts to set map config after
+	// params have been finalized will result in failure.
+	bool setMapSetting(const std::string &name,
+		const std::string &value, bool override_meta = false);
+
+	bool setMapSettingNoiseParams(const std::string &name,
+		const NoiseParams *value, bool override_meta = false);
+
+	bool loadMapMeta();
+	bool saveMapMeta();
+	MapgenParams *makeMapgenParams();
+
+private:
+	std::string m_map_meta_path;
+	Settings *m_map_settings;
+	Settings *m_user_settings;
+};
+
+#endif

src/mapgen.cpp

@@ -176,26 +176,26 @@ Mapgen *Mapgen::createMapgen(MapgenType mgtype, int mgid,
 {
 	switch (mgtype) {
 	case MAPGEN_FLAT:
-		return new MapgenFlat(mgid, params, emerge);
+		return new MapgenFlat(mgid, (MapgenFlatParams *)params, emerge);
 	case MAPGEN_FRACTAL:
-		return new MapgenFractal(mgid, params, emerge);
+		return new MapgenFractal(mgid, (MapgenFractalParams *)params, emerge);
 	case MAPGEN_SINGLENODE:
-		return new MapgenSinglenode(mgid, params, emerge);
+		return new MapgenSinglenode(mgid, (MapgenSinglenodeParams *)params, emerge);
 	case MAPGEN_V5:
-		return new MapgenV5(mgid, params, emerge);
+		return new MapgenV5(mgid, (MapgenV5Params *)params, emerge);
 	case MAPGEN_V6:
-		return new MapgenV6(mgid, params, emerge);
+		return new MapgenV6(mgid, (MapgenV6Params *)params, emerge);
 	case MAPGEN_V7:
-		return new MapgenV7(mgid, params, emerge);
+		return new MapgenV7(mgid, (MapgenV7Params *)params, emerge);
 	case MAPGEN_VALLEYS:
-		return new MapgenValleys(mgid, params, emerge);
+		return new MapgenValleys(mgid, (MapgenValleysParams *)params, emerge);
 	default:
 		return NULL;
 	}
 }
 
 
-MapgenSpecificParams *Mapgen::createMapgenParams(MapgenType mgtype)
+MapgenParams *Mapgen::createMapgenParams(MapgenType mgtype)
 {
 	switch (mgtype) {
 	case MAPGEN_FLAT:
@@ -970,52 +970,46 @@ void GenerateNotifier::getEvents(
 MapgenParams::~MapgenParams()
 {
 	delete bparams;
-	delete sparams;
 }
 
 
-void MapgenParams::load(const Settings &settings)
+void MapgenParams::readParams(const Settings *settings)
 {
 	std::string seed_str;
-	const char *seed_name = (&settings == g_settings) ? "fixed_map_seed" : "seed";
+	const char *seed_name = (settings == g_settings) ? "fixed_map_seed" : "seed";
 
-	if (settings.getNoEx(seed_name, seed_str) && !seed_str.empty())
+	if (settings->getNoEx(seed_name, seed_str)) {
+		if (!seed_str.empty())
 			seed = read_seed(seed_str.c_str());
 		else
 			myrand_bytes(&seed, sizeof(seed));
+	}
 
-	settings.getNoEx("mg_name", mg_name);
+	std::string mg_name;
-	settings.getS16NoEx("water_level", water_level);
+	if (settings->getNoEx("mg_name", mg_name))
-	settings.getS16NoEx("chunksize", chunksize);
+		this->mgtype = Mapgen::getMapgenType(mg_name);
-	settings.getFlagStrNoEx("mg_flags", flags, flagdesc_mapgen);
+
+	settings->getS16NoEx("water_level", water_level);
+	settings->getS16NoEx("chunksize", chunksize);
+	settings->getFlagStrNoEx("mg_flags", flags, flagdesc_mapgen);
 
 	delete bparams;
 	bparams = BiomeManager::createBiomeParams(BIOMEGEN_ORIGINAL);
 	if (bparams) {
-		bparams->readParams(&settings);
+		bparams->readParams(settings);
 		bparams->seed = seed;
 	}
-
-	delete sparams;
-	MapgenType mgtype = Mapgen::getMapgenType(mg_name);
-	if (mgtype != MAPGEN_INVALID) {
-		sparams = Mapgen::createMapgenParams(mgtype);
-		sparams->readParams(&settings);
-	}
 }
 
 
-void MapgenParams::save(Settings &settings) const
+void MapgenParams::writeParams(Settings *settings) const
 {
-	settings.set("mg_name", mg_name);
+	settings->set("mg_name", Mapgen::getMapgenName(mgtype));
-	settings.setU64("seed", seed);
+	settings->setU64("seed", seed);
-	settings.setS16("water_level", water_level);
+	settings->setS16("water_level", water_level);
-	settings.setS16("chunksize", chunksize);
+	settings->setS16("chunksize", chunksize);
-	settings.setFlagStr("mg_flags", flags, flagdesc_mapgen, U32_MAX);
+	settings->setFlagStr("mg_flags", flags, flagdesc_mapgen, U32_MAX);
 
 	if (bparams)
-		bparams->writeParams(&settings);
+		bparams->writeParams(settings);
-
-	if (sparams)
-		sparams->writeParams(&settings);
 }

src/mapgen.h

@@ -119,37 +119,29 @@ enum MapgenType {
 	MAPGEN_INVALID,
 };
 
-struct MapgenSpecificParams {
-	virtual void readParams(const Settings *settings) = 0;
-	virtual void writeParams(Settings *settings) const = 0;
-	virtual ~MapgenSpecificParams() {}
-};
-
 struct MapgenParams {
-	std::string mg_name;
+	MapgenType mgtype;
 	s16 chunksize;
 	u64 seed;
 	s16 water_level;
 	u32 flags;
 
 	BiomeParams *bparams;
-	MapgenSpecificParams *sparams;
 
 	MapgenParams() :
-		mg_name(MAPGEN_DEFAULT_NAME),
+		mgtype(MAPGEN_DEFAULT),
 		chunksize(5),
 		seed(0),
 		water_level(1),
 		flags(MG_CAVES | MG_LIGHT | MG_DECORATIONS),
-		bparams(NULL),
+		bparams(NULL)
-		sparams(NULL)
 	{
 	}
 
 	virtual ~MapgenParams();
 
-	void load(const Settings &settings);
+	virtual void readParams(const Settings *settings);
-	void save(Settings &settings) const;
+	virtual void writeParams(Settings *settings) const;
 };
 
 
@@ -217,7 +209,7 @@ public:
 	static const char *getMapgenName(MapgenType mgtype);
 	static Mapgen *createMapgen(MapgenType mgtype, int mgid,
 		MapgenParams *params, EmergeManager *emerge);
-	static MapgenSpecificParams *createMapgenParams(MapgenType mgtype);
+	static MapgenParams *createMapgenParams(MapgenType mgtype);
 	static void getMapgenNames(std::vector<const char *> *mgnames, bool include_hidden);
 
 private:

src/mapgen_flat.cpp

@@ -49,26 +49,24 @@ FlagDesc flagdesc_mapgen_flat[] = {
 ///////////////////////////////////////////////////////////////////////////////////////
 
 
-MapgenFlat::MapgenFlat(int mapgenid, MapgenParams *params, EmergeManager *emerge)
+MapgenFlat::MapgenFlat(int mapgenid, MapgenFlatParams *params, EmergeManager *emerge)
 	: MapgenBasic(mapgenid, params, emerge)
 {
-	MapgenFlatParams *sp = (MapgenFlatParams *)params->sparams;
+	this->spflags          = params->spflags;
-
+	this->ground_level     = params->ground_level;
-	this->spflags          = sp->spflags;
+	this->large_cave_depth = params->large_cave_depth;
-	this->ground_level     = sp->ground_level;
+	this->cave_width       = params->cave_width;
-	this->large_cave_depth = sp->large_cave_depth;
+	this->lake_threshold   = params->lake_threshold;
-	this->cave_width       = sp->cave_width;
+	this->lake_steepness   = params->lake_steepness;
-	this->lake_threshold   = sp->lake_threshold;
+	this->hill_threshold   = params->hill_threshold;
-	this->lake_steepness   = sp->lake_steepness;
+	this->hill_steepness   = params->hill_steepness;
-	this->hill_threshold   = sp->hill_threshold;
-	this->hill_steepness   = sp->hill_steepness;
 
 	//// 2D noise
-	noise_terrain      = new Noise(&sp->np_terrain,      seed, csize.X, csize.Z);
+	noise_terrain      = new Noise(&params->np_terrain,      seed, csize.X, csize.Z);
-	noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
+	noise_filler_depth = new Noise(&params->np_filler_depth, seed, csize.X, csize.Z);
 
-	MapgenBasic::np_cave1 = sp->np_cave1;
+	MapgenBasic::np_cave1 = params->np_cave1;
-	MapgenBasic::np_cave2 = sp->np_cave2;
+	MapgenBasic::np_cave2 = params->np_cave2;
 }
 
 

src/mapgen_flat.h

@@ -32,7 +32,7 @@ class BiomeManager;
 extern FlagDesc flagdesc_mapgen_flat[];
 
 
-struct MapgenFlatParams : public MapgenSpecificParams {
+struct MapgenFlatParams : public MapgenParams {
 	u32 spflags;
 	s16 ground_level;
 	s16 large_cave_depth;
@@ -55,7 +55,7 @@ struct MapgenFlatParams : public MapgenSpecificParams {
 
 class MapgenFlat : public MapgenBasic {
 public:
-	MapgenFlat(int mapgenid, MapgenParams *params, EmergeManager *emerge);
+	MapgenFlat(int mapgenid, MapgenFlatParams *params, EmergeManager *emerge);
 	~MapgenFlat();
 
 	virtual MapgenType getType() const { return MAPGEN_FLAT; }

src/mapgen_fractal.cpp

@@ -47,29 +47,27 @@ FlagDesc flagdesc_mapgen_fractal[] = {
 ///////////////////////////////////////////////////////////////////////////////////////
 
 
-MapgenFractal::MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *emerge)
+MapgenFractal::MapgenFractal(int mapgenid, MapgenFractalParams *params, EmergeManager *emerge)
 	: MapgenBasic(mapgenid, params, emerge)
 {
-	MapgenFractalParams *sp = (MapgenFractalParams *)params->sparams;
+	this->spflags    = params->spflags;
-
+	this->cave_width = params->cave_width;
-	this->spflags    = sp->spflags;
+	this->fractal    = params->fractal;
-	this->cave_width = sp->cave_width;
+	this->iterations = params->iterations;
-	this->fractal    = sp->fractal;
+	this->scale      = params->scale;
-	this->iterations = sp->iterations;
+	this->offset     = params->offset;
-	this->scale      = sp->scale;
+	this->slice_w    = params->slice_w;
-	this->offset     = sp->offset;
+	this->julia_x    = params->julia_x;
-	this->slice_w    = sp->slice_w;
+	this->julia_y    = params->julia_y;
-	this->julia_x    = sp->julia_x;
+	this->julia_z    = params->julia_z;
-	this->julia_y    = sp->julia_y;
+	this->julia_w    = params->julia_w;
-	this->julia_z    = sp->julia_z;
-	this->julia_w    = sp->julia_w;
 
 	//// 2D terrain noise
-	noise_seabed       = new Noise(&sp->np_seabed, seed, csize.X, csize.Z);
+	noise_seabed       = new Noise(&params->np_seabed, seed, csize.X, csize.Z);
-	noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
+	noise_filler_depth = new Noise(&params->np_filler_depth, seed, csize.X, csize.Z);
 
-	MapgenBasic::np_cave1 = sp->np_cave1;
+	MapgenBasic::np_cave1 = params->np_cave1;
-	MapgenBasic::np_cave2 = sp->np_cave2;
+	MapgenBasic::np_cave2 = params->np_cave2;
 
 	this->formula = fractal / 2 + fractal % 2;
 	this->julia   = fractal % 2 == 0;

src/mapgen_fractal.h

@@ -33,7 +33,7 @@ class BiomeManager;
 extern FlagDesc flagdesc_mapgen_fractal[];
 
 
-struct MapgenFractalParams : public MapgenSpecificParams {
+struct MapgenFractalParams : public MapgenParams {
 	u32 spflags;
 	float cave_width;
 	u16 fractal;
@@ -59,7 +59,7 @@ struct MapgenFractalParams : public MapgenSpecificParams {
 
 class MapgenFractal : public MapgenBasic {
 public:
-	MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *emerge);
+	MapgenFractal(int mapgenid, MapgenFractalParams *params, EmergeManager *emerge);
 	~MapgenFractal();
 
 	virtual MapgenType getType() const { return MAPGEN_FRACTAL; }

src/mapgen_singlenode.h

@@ -22,7 +22,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include "mapgen.h"
 
-struct MapgenSinglenodeParams : public MapgenSpecificParams {
+struct MapgenSinglenodeParams : public MapgenParams {
 	MapgenSinglenodeParams() {}
 	~MapgenSinglenodeParams() {}
 

src/mapgen_v5.cpp

@@ -45,25 +45,23 @@ FlagDesc flagdesc_mapgen_v5[] = {
 };
 
 
-MapgenV5::MapgenV5(int mapgenid, MapgenParams *params, EmergeManager *emerge)
+MapgenV5::MapgenV5(int mapgenid, MapgenV5Params *params, EmergeManager *emerge)
 	: MapgenBasic(mapgenid, params, emerge)
 {
-	MapgenV5Params *sp = (MapgenV5Params *)params->sparams;
+	this->spflags    = params->spflags;
-
+	this->cave_width = params->cave_width;
-	this->spflags    = sp->spflags;
-	this->cave_width = sp->cave_width;
 
 	// Terrain noise
-	noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
+	noise_filler_depth = new Noise(&params->np_filler_depth, seed, csize.X, csize.Z);
-	noise_factor       = new Noise(&sp->np_factor,       seed, csize.X, csize.Z);
+	noise_factor       = new Noise(&params->np_factor,       seed, csize.X, csize.Z);
-	noise_height       = new Noise(&sp->np_height,       seed, csize.X, csize.Z);
+	noise_height       = new Noise(&params->np_height,       seed, csize.X, csize.Z);
 
 	// 3D terrain noise
 	// 1-up 1-down overgeneration
-	noise_ground = new Noise(&sp->np_ground, seed, csize.X, csize.Y + 2, csize.Z);
+	noise_ground = new Noise(&params->np_ground, seed, csize.X, csize.Y + 2, csize.Z);
 
-	MapgenBasic::np_cave1 = sp->np_cave1;
+	MapgenBasic::np_cave1 = params->np_cave1;
-	MapgenBasic::np_cave2 = sp->np_cave2;
+	MapgenBasic::np_cave2 = params->np_cave2;
 }
 
 

src/mapgen_v5.h

@@ -30,7 +30,7 @@ class BiomeManager;
 extern FlagDesc flagdesc_mapgen_v5[];
 
 
-struct MapgenV5Params : public MapgenSpecificParams {
+struct MapgenV5Params : public MapgenParams {
 	u32 spflags;
 	float cave_width;
 	NoiseParams np_filler_depth;
@@ -50,7 +50,7 @@ struct MapgenV5Params : public MapgenSpecificParams {
 
 class MapgenV5 : public MapgenBasic {
 public:
-	MapgenV5(int mapgenid, MapgenParams *params, EmergeManager *emerge);
+	MapgenV5(int mapgenid, MapgenV5Params *params, EmergeManager *emerge);
 	~MapgenV5();
 
 	virtual MapgenType getType() const { return MAPGEN_V5; }

src/mapgen_v6.cpp

@@ -53,7 +53,7 @@ FlagDesc flagdesc_mapgen_v6[] = {
 /////////////////////////////////////////////////////////////////////////////
 
 
-MapgenV6::MapgenV6(int mapgenid, MapgenParams *params, EmergeManager *emerge)
+MapgenV6::MapgenV6(int mapgenid, MapgenV6Params *params, EmergeManager *emerge)
 	: Mapgen(mapgenid, params, emerge)
 {
 	this->m_emerge = emerge;
@@ -61,26 +61,25 @@ MapgenV6::MapgenV6(int mapgenid, MapgenParams *params, EmergeManager *emerge)
 
 	this->heightmap = new s16[csize.X * csize.Z];
 
-	MapgenV6Params *sp = (MapgenV6Params *)params->sparams;
+	this->spflags     = params->spflags;
-	this->spflags     = sp->spflags;
+	this->freq_desert = params->freq_desert;
-	this->freq_desert = sp->freq_desert;
+	this->freq_beach  = params->freq_beach;
-	this->freq_beach  = sp->freq_beach;
 
-	np_cave        = &sp->np_cave;
+	np_cave        = &params->np_cave;
-	np_humidity    = &sp->np_humidity;
+	np_humidity    = &params->np_humidity;
-	np_trees       = &sp->np_trees;
+	np_trees       = &params->np_trees;
-	np_apple_trees = &sp->np_apple_trees;
+	np_apple_trees = &params->np_apple_trees;
 
 	//// Create noise objects
-	noise_terrain_base   = new Noise(&sp->np_terrain_base,   seed, csize.X, csize.Y);
+	noise_terrain_base   = new Noise(&params->np_terrain_base,   seed, csize.X, csize.Y);
-	noise_terrain_higher = new Noise(&sp->np_terrain_higher, seed, csize.X, csize.Y);
+	noise_terrain_higher = new Noise(&params->np_terrain_higher, seed, csize.X, csize.Y);
-	noise_steepness      = new Noise(&sp->np_steepness,      seed, csize.X, csize.Y);
+	noise_steepness      = new Noise(&params->np_steepness,      seed, csize.X, csize.Y);
-	noise_height_select  = new Noise(&sp->np_height_select,  seed, csize.X, csize.Y);
+	noise_height_select  = new Noise(&params->np_height_select,  seed, csize.X, csize.Y);
-	noise_mud            = new Noise(&sp->np_mud,            seed, csize.X, csize.Y);
+	noise_mud            = new Noise(&params->np_mud,            seed, csize.X, csize.Y);
-	noise_beach          = new Noise(&sp->np_beach,          seed, csize.X, csize.Y);
+	noise_beach          = new Noise(&params->np_beach,          seed, csize.X, csize.Y);
-	noise_biome          = new Noise(&sp->np_biome,          seed,
+	noise_biome          = new Noise(&params->np_biome,          seed,
 			csize.X + 2 * MAP_BLOCKSIZE, csize.Y + 2 * MAP_BLOCKSIZE);
-	noise_humidity       = new Noise(&sp->np_humidity,       seed,
+	noise_humidity       = new Noise(&params->np_humidity,       seed,
 			csize.X + 2 * MAP_BLOCKSIZE, csize.Y + 2 * MAP_BLOCKSIZE);
 
 	//// Resolve nodes to be used

src/mapgen_v6.h

@@ -53,7 +53,7 @@ enum BiomeV6Type
 };
 
 
-struct MapgenV6Params : public MapgenSpecificParams {
+struct MapgenV6Params : public MapgenParams {
 	u32 spflags;
 	float freq_desert;
 	float freq_beach;
@@ -124,7 +124,7 @@ public:
 	content_t c_mossycobble;
 	content_t c_stair_cobble;
 
-	MapgenV6(int mapgenid, MapgenParams *params, EmergeManager *emerge);
+	MapgenV6(int mapgenid, MapgenV6Params *params, EmergeManager *emerge);
 	~MapgenV6();
 
 	virtual MapgenType getType() const { return MAPGEN_V6; }

src/mapgen_v7.cpp

@@ -50,30 +50,28 @@ FlagDesc flagdesc_mapgen_v7[] = {
 ///////////////////////////////////////////////////////////////////////////////
 
 
-MapgenV7::MapgenV7(int mapgenid, MapgenParams *params, EmergeManager *emerge)
+MapgenV7::MapgenV7(int mapgenid, MapgenV7Params *params, EmergeManager *emerge)
 	: MapgenBasic(mapgenid, params, emerge)
 {
-	MapgenV7Params *sp = (MapgenV7Params *)params->sparams;
+	this->spflags    = params->spflags;
-
+	this->cave_width = params->cave_width;
-	this->spflags    = sp->spflags;
-	this->cave_width = sp->cave_width;
 
 	//// Terrain noise
-	noise_terrain_base    = new Noise(&sp->np_terrain_base,    seed, csize.X, csize.Z);
+	noise_terrain_base    = new Noise(&params->np_terrain_base,    seed, csize.X, csize.Z);
-	noise_terrain_alt     = new Noise(&sp->np_terrain_alt,     seed, csize.X, csize.Z);
+	noise_terrain_alt     = new Noise(&params->np_terrain_alt,     seed, csize.X, csize.Z);
-	noise_terrain_persist = new Noise(&sp->np_terrain_persist, seed, csize.X, csize.Z);
+	noise_terrain_persist = new Noise(&params->np_terrain_persist, seed, csize.X, csize.Z);
-	noise_height_select   = new Noise(&sp->np_height_select,   seed, csize.X, csize.Z);
+	noise_height_select   = new Noise(&params->np_height_select,   seed, csize.X, csize.Z);
-	noise_filler_depth    = new Noise(&sp->np_filler_depth,    seed, csize.X, csize.Z);
+	noise_filler_depth    = new Noise(&params->np_filler_depth,    seed, csize.X, csize.Z);
-	noise_mount_height    = new Noise(&sp->np_mount_height,    seed, csize.X, csize.Z);
+	noise_mount_height    = new Noise(&params->np_mount_height,    seed, csize.X, csize.Z);
-	noise_ridge_uwater    = new Noise(&sp->np_ridge_uwater,    seed, csize.X, csize.Z);
+	noise_ridge_uwater    = new Noise(&params->np_ridge_uwater,    seed, csize.X, csize.Z);
 
 	//// 3d terrain noise
 	// 1-up 1-down overgeneration
-	noise_mountain = new Noise(&sp->np_mountain, seed, csize.X, csize.Y + 2, csize.Z);
+	noise_mountain = new Noise(&params->np_mountain, seed, csize.X, csize.Y + 2, csize.Z);
-	noise_ridge    = new Noise(&sp->np_ridge,    seed, csize.X, csize.Y + 2, csize.Z);
+	noise_ridge    = new Noise(&params->np_ridge,    seed, csize.X, csize.Y + 2, csize.Z);
 
-	MapgenBasic::np_cave1 = sp->np_cave1;
+	MapgenBasic::np_cave1 = params->np_cave1;
-	MapgenBasic::np_cave2 = sp->np_cave2;
+	MapgenBasic::np_cave2 = params->np_cave2;
 }
 
 

src/mapgen_v7.h

@@ -32,7 +32,7 @@ class BiomeManager;
 extern FlagDesc flagdesc_mapgen_v7[];
 
 
-struct MapgenV7Params : public MapgenSpecificParams {
+struct MapgenV7Params : public MapgenParams {
 	u32 spflags;
 	float cave_width;
 	NoiseParams np_terrain_base;
@@ -56,7 +56,7 @@ struct MapgenV7Params : public MapgenSpecificParams {
 
 class MapgenV7 : public MapgenBasic {
 public:
-	MapgenV7(int mapgenid, MapgenParams *params, EmergeManager *emerge);
+	MapgenV7(int mapgenid, MapgenV7Params *params, EmergeManager *emerge);
 	~MapgenV7();
 
 	virtual MapgenType getType() const { return MAPGEN_V7; }

src/mapgen_valleys.cpp

@@ -64,7 +64,7 @@ static FlagDesc flagdesc_mapgen_valleys[] = {
 ///////////////////////////////////////////////////////////////////////////////
 
 
-MapgenValleys::MapgenValleys(int mapgenid, MapgenParams *params, EmergeManager *emerge)
+MapgenValleys::MapgenValleys(int mapgenid, MapgenValleysParams *params, EmergeManager *emerge)
 	: MapgenBasic(mapgenid, params, emerge)
 {
 	// NOTE: MapgenValleys has a hard dependency on BiomeGenOriginal
@@ -73,34 +73,33 @@ MapgenValleys::MapgenValleys(int mapgenid, MapgenParams *params, EmergeManager *
 	this->map_gen_limit = MYMIN(MAX_MAP_GENERATION_LIMIT,
 			g_settings->getU16("map_generation_limit"));
 
-	MapgenValleysParams *sp = (MapgenValleysParams *)params->sparams;
 	BiomeParamsOriginal *bp = (BiomeParamsOriginal *)params->bparams;
 
-	this->spflags            = sp->spflags;
+	this->spflags            = params->spflags;
-	this->altitude_chill     = sp->altitude_chill;
+	this->altitude_chill     = params->altitude_chill;
-	this->large_cave_depth   = sp->large_cave_depth;
+	this->large_cave_depth   = params->large_cave_depth;
-	this->lava_features_lim  = rangelim(sp->lava_features, 0, 10);
+	this->lava_features_lim  = rangelim(params->lava_features, 0, 10);
-	this->massive_cave_depth = sp->massive_cave_depth;
+	this->massive_cave_depth = params->massive_cave_depth;
-	this->river_depth_bed    = sp->river_depth + 1.f;
+	this->river_depth_bed    = params->river_depth + 1.f;
-	this->river_size_factor  = sp->river_size / 100.f;
+	this->river_size_factor  = params->river_size / 100.f;
-	this->water_features_lim = rangelim(sp->water_features, 0, 10);
+	this->water_features_lim = rangelim(params->water_features, 0, 10);
-	this->cave_width         = sp->cave_width;
+	this->cave_width         = params->cave_width;
 
 	//// 2D Terrain noise
-	noise_filler_depth       = new Noise(&sp->np_filler_depth,       seed, csize.X, csize.Z);
+	noise_filler_depth       = new Noise(&params->np_filler_depth,       seed, csize.X, csize.Z);
-	noise_inter_valley_slope = new Noise(&sp->np_inter_valley_slope, seed, csize.X, csize.Z);
+	noise_inter_valley_slope = new Noise(&params->np_inter_valley_slope, seed, csize.X, csize.Z);
-	noise_rivers             = new Noise(&sp->np_rivers,             seed, csize.X, csize.Z);
+	noise_rivers             = new Noise(&params->np_rivers,             seed, csize.X, csize.Z);
-	noise_terrain_height     = new Noise(&sp->np_terrain_height,     seed, csize.X, csize.Z);
+	noise_terrain_height     = new Noise(&params->np_terrain_height,     seed, csize.X, csize.Z);
-	noise_valley_depth       = new Noise(&sp->np_valley_depth,       seed, csize.X, csize.Z);
+	noise_valley_depth       = new Noise(&params->np_valley_depth,       seed, csize.X, csize.Z);
-	noise_valley_profile     = new Noise(&sp->np_valley_profile,     seed, csize.X, csize.Z);
+	noise_valley_profile     = new Noise(&params->np_valley_profile,     seed, csize.X, csize.Z);
 
 	//// 3D Terrain noise
 	// 1-up 1-down overgeneration
-	noise_inter_valley_fill = new Noise(&sp->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(&sp->np_cave1,             seed, csize.X, csize.Y + 1, csize.Z);
+	noise_cave1             = new Noise(&params->np_cave1,             seed, csize.X, csize.Y + 1, csize.Z);
-	noise_cave2             = new Noise(&sp->np_cave2,             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(&sp->np_massive_caves,     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);
 
 	this->humid_rivers       = (spflags & MGVALLEYS_HUMID_RIVERS);
 	this->use_altitude_chill = (spflags & MGVALLEYS_ALT_CHILL);

src/mapgen_valleys.h

@@ -46,7 +46,7 @@ class BiomeGenOriginal;
 //extern Profiler *mapgen_profiler;
 
 
-struct MapgenValleysParams : public MapgenSpecificParams {
+struct MapgenValleysParams : public MapgenParams {
 	u32 spflags;
 	s16 large_cave_depth;
 	s16 massive_cave_depth;
@@ -88,7 +88,7 @@ struct TerrainNoise {
 class MapgenValleys : public MapgenBasic {
 public:
 
-	MapgenValleys(int mapgenid, MapgenParams *params, EmergeManager *emerge);
+	MapgenValleys(int mapgenid, MapgenValleysParams *params, EmergeManager *emerge);
 	~MapgenValleys();
 
 	virtual MapgenType getType() const { return MAPGEN_VALLEYS; }

src/script/lua_api/l_mapgen.cpp

@@ -600,24 +600,37 @@ int ModApiMapgen::l_get_mapgen_params(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
 
-	MapgenParams *params = &getServer(L)->getEmergeManager()->params;
+	log_deprecated(L, "get_mapgen_params is deprecated; "
+		"use get_mapgen_setting instead");
+
+	std::string value;
+
+	MapSettingsManager *settingsmgr =
+		getServer(L)->getEmergeManager()->map_settings_mgr;
 
 	lua_newtable(L);
 
-	lua_pushstring(L, params->mg_name.c_str());
+	settingsmgr->getMapSetting("mg_name", &value);
+	lua_pushstring(L, value.c_str());
 	lua_setfield(L, -2, "mgname");
 
-	lua_pushinteger(L, params->seed);
+	settingsmgr->getMapSetting("seed", &value);
+	std::istringstream ss(value);
+	u64 seed;
+	ss >> seed;
+	lua_pushinteger(L, seed);
 	lua_setfield(L, -2, "seed");
 
-	lua_pushinteger(L, params->water_level);
+	settingsmgr->getMapSetting("water_level", &value);
+	lua_pushinteger(L, stoi(value, -32768, 32767));
 	lua_setfield(L, -2, "water_level");
 
-	lua_pushinteger(L, params->chunksize);
+	settingsmgr->getMapSetting("chunksize", &value);
+	lua_pushinteger(L, stoi(value, -32768, 32767));
 	lua_setfield(L, -2, "chunksize");
 
-	std::string flagstr = writeFlagString(params->flags, flagdesc_mapgen, U32_MAX);
+	settingsmgr->getMapSetting("mg_flags", &value);
-	lua_pushstring(L, flagstr.c_str());
+	lua_pushstring(L, value.c_str());
 	lua_setfield(L, -2, "flags");
 
 	return 1;
@@ -630,44 +643,120 @@ int ModApiMapgen::l_set_mapgen_params(lua_State *L)
 {
 	NO_MAP_LOCK_REQUIRED;
 
+	log_deprecated(L, "set_mapgen_params is deprecated; "
+		"use set_mapgen_setting instead");
+
 	if (!lua_istable(L, 1))
 		return 0;
 
-	EmergeManager *emerge = getServer(L)->getEmergeManager();
+	MapSettingsManager *settingsmgr =
-	if (emerge->isRunning())
+		getServer(L)->getEmergeManager()->map_settings_mgr;
-		throw LuaError("Cannot set parameters while mapgen is running");
-
-	MapgenParams *params = &emerge->params;
-	u32 flags = 0, flagmask = 0;
 
 	lua_getfield(L, 1, "mgname");
-	if (lua_isstring(L, -1)) {
+	if (lua_isstring(L, -1))
-		params->mg_name = lua_tostring(L, -1);
+		settingsmgr->setMapSetting("mg_name", lua_tostring(L, -1), true);
-		delete params->sparams;
-		params->sparams = NULL;
-	}
 
 	lua_getfield(L, 1, "seed");
 	if (lua_isnumber(L, -1))
-		params->seed = lua_tointeger(L, -1);
+		settingsmgr->setMapSetting("seed", lua_tostring(L, -1), true);
 
 	lua_getfield(L, 1, "water_level");
 	if (lua_isnumber(L, -1))
-		params->water_level = lua_tointeger(L, -1);
+		settingsmgr->setMapSetting("water_level", lua_tostring(L, -1), true);
 
 	lua_getfield(L, 1, "chunksize");
 	if (lua_isnumber(L, -1))
-		params->chunksize = lua_tointeger(L, -1);
+		settingsmgr->setMapSetting("chunksize", lua_tostring(L, -1), true);
 
 	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)) {
+	lua_getfield(L, 1, "flags");
-		params->flags &= ~flagmask;
+	if (lua_isstring(L, -1))
-		params->flags |= flags;
+		settingsmgr->setMapSetting("mg_flags", lua_tostring(L, -1), true);
+
+	return 0;
+}
+
+// get_mapgen_setting(name)
+int ModApiMapgen::l_get_mapgen_setting(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+
+	std::string value;
+	MapSettingsManager *settingsmgr =
+		getServer(L)->getEmergeManager()->map_settings_mgr;
+
+	const char *name = luaL_checkstring(L, 1);
+	if (!settingsmgr->getMapSetting(name, &value))
+		return 0;
+
+	lua_pushstring(L, value.c_str());
+	return 1;
+}
+
+// get_mapgen_setting_noiseparams(name)
+int ModApiMapgen::l_get_mapgen_setting_noiseparams(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+
+	NoiseParams np;
+	MapSettingsManager *settingsmgr =
+		getServer(L)->getEmergeManager()->map_settings_mgr;
+
+	const char *name = luaL_checkstring(L, 1);
+	if (!settingsmgr->getMapSettingNoiseParams(name, &np))
+		return 0;
+
+	push_noiseparams(L, &np);
+	return 1;
+}
+
+// set_mapgen_setting(name, value, override_meta)
+// set mapgen config values
+int ModApiMapgen::l_set_mapgen_setting(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+
+	MapSettingsManager *settingsmgr =
+		getServer(L)->getEmergeManager()->map_settings_mgr;
+
+	const char *name   = luaL_checkstring(L, 1);
+	const char *value  = luaL_checkstring(L, 2);
+	bool override_meta = lua_isboolean(L, 3) ? lua_toboolean(L, 3) : false;
+
+	if (!settingsmgr->setMapSetting(name, value, override_meta)) {
+		errorstream << "set_mapgen_setting: cannot set '"
+			<< name << "' after initialization" << std::endl;
+	}
+
+	return 0;
+}
+
+
+// set_mapgen_setting_noiseparams(name, noiseparams, set_default)
+// set mapgen config values for noise parameters
+int ModApiMapgen::l_set_mapgen_setting_noiseparams(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+
+	MapSettingsManager *settingsmgr =
+		getServer(L)->getEmergeManager()->map_settings_mgr;
+
+	const char *name = luaL_checkstring(L, 1);
+
+	NoiseParams np;
+	if (!read_noiseparams(L, 2, &np)) {
+		errorstream << "set_mapgen_setting_noiseparams: cannot set '" << name
+			<< "'; invalid noiseparams table" << std::endl;
+		return 0;
+	}
+
+	bool override_meta = lua_isboolean(L, 3) ? lua_toboolean(L, 3) : false;
+
+	if (!settingsmgr->setMapSettingNoiseParams(name, &np, override_meta)) {
+		errorstream << "set_mapgen_setting_noiseparams: cannot set '"
+			<< name << "' after initialization" << std::endl;
 	}
 
 	return 0;
@@ -683,8 +772,11 @@ int ModApiMapgen::l_set_noiseparams(lua_State *L)
 	const char *name = luaL_checkstring(L, 1);
 
 	NoiseParams np;
-	if (!read_noiseparams(L, 2, &np))
+	if (!read_noiseparams(L, 2, &np)) {
+		errorstream << "set_noiseparams: cannot set '" << name
+			<< "'; invalid noiseparams table" << std::endl;
 		return 0;
+	}
 
 	bool set_default = lua_isboolean(L, 3) ? lua_toboolean(L, 3) : true;
 
@@ -1143,7 +1235,7 @@ int ModApiMapgen::l_generate_ores(lua_State *L)
 	EmergeManager *emerge = getServer(L)->getEmergeManager();
 
 	Mapgen mg;
-	mg.seed = emerge->params.seed;
+	mg.seed = emerge->mgparams->seed;
 	mg.vm   = LuaVoxelManip::checkobject(L, 1)->vm;
 	mg.ndef = getServer(L)->getNodeDefManager();
 
@@ -1169,7 +1261,7 @@ int ModApiMapgen::l_generate_decorations(lua_State *L)
 	EmergeManager *emerge = getServer(L)->getEmergeManager();
 
 	Mapgen mg;
-	mg.seed = emerge->params.seed;
+	mg.seed = emerge->mgparams->seed;
 	mg.vm   = LuaVoxelManip::checkobject(L, 1)->vm;
 	mg.ndef = getServer(L)->getNodeDefManager();
 
@@ -1393,6 +1485,10 @@ void ModApiMapgen::Initialize(lua_State *L, int top)
 
 	API_FCT(get_mapgen_params);
 	API_FCT(set_mapgen_params);
+	API_FCT(get_mapgen_setting);
+	API_FCT(set_mapgen_setting);
+	API_FCT(get_mapgen_setting_noiseparams);
+	API_FCT(set_mapgen_setting_noiseparams);
 	API_FCT(set_noiseparams);
 	API_FCT(get_noiseparams);
 	API_FCT(set_gen_notify);

src/script/lua_api/l_mapgen.h

@@ -40,6 +40,18 @@ private:
 	// set mapgen parameters
 	static int l_set_mapgen_params(lua_State *L);
 
+	// get_mapgen_setting(name)
+	static int l_get_mapgen_setting(lua_State *L);
+
+	// set_mapgen_setting(name, value, override_meta)
+	static int l_set_mapgen_setting(lua_State *L);
+
+	// get_mapgen_setting_noiseparams(name)
+	static int l_get_mapgen_setting_noiseparams(lua_State *L);
+
+	// set_mapgen_setting_noiseparams(name, value, override_meta)
+	static int l_set_mapgen_setting_noiseparams(lua_State *L);
+
 	// set_noiseparam_defaults(name, noiseparams, set_default)
 	static int l_set_noiseparams(lua_State *L);
 

src/script/lua_api/l_vmanip.cpp

@@ -190,7 +190,7 @@ int LuaVoxelManip::l_calc_lighting(lua_State *L)
 	Mapgen mg;
 	mg.vm          = vm;
 	mg.ndef        = ndef;
-	mg.water_level = emerge->params.water_level;
+	mg.water_level = emerge->mgparams->water_level;
 
 	mg.calcLighting(pmin, pmax, fpmin, fpmax, propagate_shadow);
 

src/server.cpp

@@ -266,9 +266,6 @@ Server::Server(
 	//lock environment
 	MutexAutoLock envlock(m_env_mutex);
 
-	// Load mapgen params from Settings
-	m_emerge->loadMapgenParams();
-
 	// Create the Map (loads map_meta.txt, overriding configured mapgen params)
 	ServerMap *servermap = new ServerMap(path_world, this, m_emerge);
 
@@ -331,8 +328,11 @@ Server::Server(
 
 	m_clients.setEnv(m_env);
 
+	if (!servermap->settings_mgr.makeMapgenParams())
+		FATAL_ERROR("Couldn't create any mapgen type");
+
 	// Initialize mapgens
-	m_emerge->initMapgens();
+	m_emerge->initMapgens(servermap->getMapgenParams());
 
 	m_enable_rollback_recording = g_settings->getBool("enable_rollback_recording");
 	if (m_enable_rollback_recording) {
@@ -402,11 +402,8 @@ Server::~Server()
 	m_emerge->stopThreads();
 
 	// Delete things in the reverse order of creation
-	delete m_env;
-
-	// N.B. the EmergeManager should be deleted after the Environment since Map
-	// depends on EmergeManager to write its current params to the map meta
 	delete m_emerge;
+	delete m_env;
 	delete m_rollback;
 	delete m_banmanager;
 	delete m_event;
@@ -655,7 +652,7 @@ void Server::AsyncRunStep(bool initial_step)
 					m_env->getGameTime(),
 					m_lag,
 					m_gamespec.id,
-					m_emerge->params.mg_name,
+					Mapgen::getMapgenName(m_emerge->mgparams->mgtype),
 					m_mods);
 			counter = 0.01;
 		}

src/subgame.cpp

@@ -313,8 +313,8 @@ bool loadGameConfAndInitWorld(const std::string &path, const SubgameSpec &gamesp
 		Settings conf;
 		MapgenParams params;
 
-		params.load(*g_settings);
+		params.readParams(g_settings);
-		params.save(conf);
+		params.writeParams(&conf);
 		conf.writeLines(oss);
 		oss << "[end_of_params]\n";
 

src/unittest/CMakeLists.txt

@@ -6,6 +6,7 @@ set (UNITTEST_SRCS
 	${CMAKE_CURRENT_SOURCE_DIR}/test_connection.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_filepath.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_inventory.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/test_map_settings_manager.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_mapnode.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_nodedef.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/test_noderesolver.cpp

src/unittest/test_map_settings_manager.cpp

@@ -0,0 +1,255 @@
+ /*
+Minetest
+Copyright (C) 2010-2014 kwolekr, Ryan Kwolek <kwolekr@minetest.net>
+
+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 "test.h"
+
+#include "noise.h"
+#include "settings.h"
+#include "mapgen_v5.h"
+#include "util/sha1.h"
+#include "map_settings_manager.h"
+
+class TestMapSettingsManager : public TestBase {
+public:
+	TestMapSettingsManager() { TestManager::registerTestModule(this); }
+	const char *getName() { return "TestMapSettingsManager"; }
+
+	void makeUserConfig(Settings *conf);
+	std::string makeMetaFile(bool make_corrupt);
+
+	void runTests(IGameDef *gamedef);
+
+	void testMapSettingsManager();
+	void testMapMetaSaveLoad();
+	void testMapMetaFailures();
+};
+
+static TestMapSettingsManager g_test_instance;
+
+void TestMapSettingsManager::runTests(IGameDef *gamedef)
+{
+	TEST(testMapSettingsManager);
+	TEST(testMapMetaSaveLoad);
+	TEST(testMapMetaFailures);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+
+void check_noise_params(const NoiseParams *np1, const NoiseParams *np2)
+{
+	UASSERTEQ(float, np1->offset, np2->offset);
+	UASSERTEQ(float, np1->scale, np2->scale);
+	UASSERT(np1->spread == np2->spread);
+	UASSERTEQ(s32, np1->seed, np2->seed);
+	UASSERTEQ(u16, np1->octaves, np2->octaves);
+	UASSERTEQ(float, np1->persist, np2->persist);
+	UASSERTEQ(float, np1->lacunarity, np2->lacunarity);
+	UASSERTEQ(u32, np1->flags, np2->flags);
+}
+
+
+std::string read_file_to_string(const std::string &filepath)
+{
+	std::string buf;
+	FILE *f = fopen(filepath.c_str(), "rb");
+	if (!f)
+		return "";
+
+	fseek(f, 0, SEEK_END);
+
+	long filesize = ftell(f);
+	if (filesize == -1)
+		return "";
+	rewind(f);
+
+	buf.resize(filesize);
+
+	fread(&buf[0], 1, filesize, f);
+
+	fclose(f);
+	return buf;
+}
+
+
+void TestMapSettingsManager::makeUserConfig(Settings *conf)
+{
+	conf->set("mg_name", "v7");
+	conf->set("seed", "5678");
+	conf->set("water_level", "20");
+	conf->set("mgv5_np_factor", "0, 12,  (500, 250, 500), 920382, 5, 0.45, 3.0");
+	conf->set("mgv5_np_height", "0, 15, (500, 250, 500), 841746,  5, 0.5,  3.0");
+	conf->set("mgv5_np_filler_depth", "20, 1, (150, 150, 150), 261, 4, 0.7,  1.0");
+	conf->set("mgv5_np_ground", "-43, 40, (80,  80,  80),  983240, 4, 0.55, 2.0");
+}
+
+
+std::string TestMapSettingsManager::makeMetaFile(bool make_corrupt)
+{
+	std::string metafile = getTestTempFile();
+
+	const char *metafile_contents =
+		"mg_name = v5\n"
+		"seed = 1234\n"
+		"mg_flags = light\n"
+		"mgv5_np_filler_depth = 20, 1, (150, 150, 150), 261, 4, 0.7,  1.0\n"
+		"mgv5_np_height = 20, 10, (250, 250, 250), 84174,  4, 0.5,  1.0\n";
+
+	FILE *f = fopen(metafile.c_str(), "wb");
+	UASSERT(f != NULL);
+
+	fputs(metafile_contents, f);
+	if (!make_corrupt)
+		fputs("[end_of_params]\n", f);
+
+	fclose(f);
+
+	return metafile;
+}
+
+
+void TestMapSettingsManager::testMapSettingsManager()
+{
+	Settings user_settings;
+	makeUserConfig(&user_settings);
+
+	std::string test_mapmeta_path = makeMetaFile(false);
+
+	MapSettingsManager mgr(&user_settings, test_mapmeta_path);
+	std::string value;
+
+	UASSERT(mgr.getMapSetting("mg_name", &value));
+	UASSERT(value == "v7");
+
+	// Pretend we're initializing the ServerMap
+	UASSERT(mgr.loadMapMeta());
+
+	// Pretend some scripts are requesting mapgen params
+	UASSERT(mgr.getMapSetting("mg_name", &value));
+	UASSERT(value == "v5");
+	UASSERT(mgr.getMapSetting("seed", &value));
+	UASSERT(value == "1234");
+	UASSERT(mgr.getMapSetting("water_level", &value));
+	UASSERT(value == "20");
+
+    // Pretend we have some mapgen settings configured from the scripting
+	UASSERT(mgr.setMapSetting("water_level", "15"));
+	UASSERT(mgr.setMapSetting("seed", "02468"));
+	UASSERT(mgr.setMapSetting("mg_flags", "nolight", true));
+
+	NoiseParams script_np_filler_depth(0, 100, v3f(200, 100, 200), 261, 4, 0.7, 2.0);
+	NoiseParams script_np_factor(0, 100, v3f(50, 50, 50), 920381, 3, 0.45, 2.0);
+	NoiseParams script_np_height(0, 100, v3f(450, 450, 450), 84174, 4, 0.5, 2.0);
+	NoiseParams meta_np_height(20, 10, v3f(250, 250, 250), 84174,  4, 0.5,  1.0);
+	NoiseParams user_np_ground(-43, 40, v3f(80,  80,  80),  983240, 4, 0.55, 2.0, NOISE_FLAG_EASED);
+
+	mgr.setMapSettingNoiseParams("mgv5_np_filler_depth", &script_np_filler_depth, true);
+	mgr.setMapSettingNoiseParams("mgv5_np_height", &script_np_height);
+	mgr.setMapSettingNoiseParams("mgv5_np_factor", &script_np_factor);
+
+	// Now make our Params and see if the values are correctly sourced
+	MapgenParams *params = mgr.makeMapgenParams();
+	UASSERT(params->mgtype == MAPGEN_V5);
+	UASSERT(params->chunksize == 5);
+	UASSERT(params->water_level == 15);
+	UASSERT(params->seed == 1234);
+	UASSERT((params->flags & MG_LIGHT) == 0);
+
+	MapgenV5Params *v5params = (MapgenV5Params *)params;
+
+	check_noise_params(&v5params->np_filler_depth, &script_np_filler_depth);
+	check_noise_params(&v5params->np_factor, &script_np_factor);
+	check_noise_params(&v5params->np_height, &meta_np_height);
+	check_noise_params(&v5params->np_ground, &user_np_ground);
+
+	UASSERT(mgr.setMapSetting("foobar", "25") == false);
+
+	// Pretend the ServerMap is shutting down
+	UASSERT(mgr.saveMapMeta());
+
+	// Make sure our interface expectations are met
+	UASSERT(mgr.mapgen_params == params);
+	UASSERT(mgr.makeMapgenParams() == params);
+
+	// Load the resulting map_meta.txt and make sure it contains what we expect
+	unsigned char expected_contents_hash[20] = {
+		0xf6, 0x44, 0x90, 0xb7, 0xab, 0xd8, 0x91, 0xf4, 0x08, 0x96,
+		0xfc, 0x7e, 0xed, 0x01, 0xc5, 0x9a, 0xfd, 0x2f, 0x2d, 0x79
+	};
+
+	SHA1 ctx;
+	std::string metafile_contents = read_file_to_string(test_mapmeta_path);
+	ctx.addBytes(&metafile_contents[0], metafile_contents.size());
+	unsigned char *sha1_result = ctx.getDigest();
+	int resultdiff = memcmp(sha1_result, expected_contents_hash, 20);
+	free(sha1_result);
+
+	UASSERT(!resultdiff);
+}
+
+
+void TestMapSettingsManager::testMapMetaSaveLoad()
+{
+	Settings conf;
+	std::string path = getTestTempDirectory()
+		+ DIR_DELIM + "foobar" + DIR_DELIM + "map_meta.txt";
+
+	// Create a set of mapgen params and save them to map meta
+	conf.set("seed", "12345");
+	conf.set("water_level", "5");
+	MapSettingsManager mgr1(&conf, path);
+	MapgenParams *params1 = mgr1.makeMapgenParams();
+	UASSERT(params1);
+	UASSERT(mgr1.saveMapMeta());
+
+	// Now try loading the map meta to mapgen params
+	conf.set("seed", "67890");
+	conf.set("water_level", "32");
+	MapSettingsManager mgr2(&conf, path);
+	UASSERT(mgr2.loadMapMeta());
+	MapgenParams *params2 = mgr2.makeMapgenParams();
+	UASSERT(params2);
+
+	// Check that both results are correct
+	UASSERTEQ(u64, params1->seed, 12345);
+	UASSERTEQ(s16, params1->water_level, 5);
+	UASSERTEQ(u64, params2->seed, 12345);
+	UASSERTEQ(s16, params2->water_level, 5);
+}
+
+
+void TestMapSettingsManager::testMapMetaFailures()
+{
+	std::string test_mapmeta_path;
+	Settings conf;
+
+	// Check to see if it'll fail on a non-existent map meta file
+	test_mapmeta_path = "woobawooba/fgdfg/map_meta.txt";
+	UASSERT(!fs::PathExists(test_mapmeta_path));
+
+	MapSettingsManager mgr1(&conf, test_mapmeta_path);
+	UASSERT(!mgr1.loadMapMeta());
+
+	// Check to see if it'll fail on a corrupt map meta file
+	test_mapmeta_path = makeMetaFile(true);
+	UASSERT(fs::PathExists(test_mapmeta_path));
+
+	MapSettingsManager mgr2(&conf, test_mapmeta_path);
+	UASSERT(!mgr2.loadMapMeta());
+}