Replace old active block random node modifying things with actual ActiveBlockModifiers

11 files changed, 526 insertions, 420 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 9d699e976..8c966a690 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -94,6 +94,7 @@ configure_file(
 )
 
 set(common_SRCS
+	content_abm.cpp
 	craftdef.cpp
 	nameidmapping.cpp
 	tooldef.cpp
diff --git a/src/content_abm.cpp b/src/content_abm.cpp
new file mode 100644
index 000000000..44978c5bb
--- /dev/null
+++ b/src/content_abm.cpp
@@ -0,0 +1,269 @@
+/*
+Minetest-c55
+Copyright (C) 2011 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 General Public License as published by
+the Free Software Foundation; either version 2 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 General Public License for more details.
+
+You should have received a copy of the GNU 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 "content_abm.h"
+
+#include "environment.h"
+#include "gamedef.h"
+#include "nodedef.h"
+#include "content_sao.h"
+#include "settings.h"
+#include "mapblock.h" // For getNodeBlockPos
+#include "mapgen.h" // For mapgen::make_tree
+
+#define PP(x) "("<<(x).X<<","<<(x).Y<<","<<(x).Z<<")"
+
+class GrowGrassABM : public ActiveBlockModifier
+{
+private:
+public:
+	virtual std::set<std::string> getTriggerContents()
+	{
+		std::set<std::string> s;
+		s.insert("dirt");
+		return s;
+	}
+	virtual float getTriggerInterval()
+	{ return 10.0; }
+	virtual u32 getTriggerChance()
+	{ return 20; }
+	virtual void trigger(ServerEnvironment *env, v3s16 p, MapNode n)
+	{
+		INodeDefManager *ndef = env->getGameDef()->ndef();
+		ServerMap *map = &env->getServerMap();
+		
+		MapNode n_top = map->getNodeNoEx(p+v3s16(0,1,0));
+		if(ndef->get(n_top).light_propagates &&
+				!ndef->get(n_top).isLiquid() &&
+				n_top.getLightBlend(env->getDayNightRatio(), ndef) >= 13)
+		{
+			n.setContent(ndef->getId("dirt_with_grass"));
+			map->addNodeWithEvent(p, n);
+		}
+	}
+};
+
+class RemoveGrassABM : public ActiveBlockModifier
+{
+private:
+public:
+	virtual std::set<std::string> getTriggerContents()
+	{
+		std::set<std::string> s;
+		s.insert("dirt_with_grass");
+		return s;
+	}
+	virtual float getTriggerInterval()
+	{ return 10.0; }
+	virtual u32 getTriggerChance()
+	{ return 1; }
+	virtual void trigger(ServerEnvironment *env, v3s16 p, MapNode n)
+	{
+		INodeDefManager *ndef = env->getGameDef()->ndef();
+		ServerMap *map = &env->getServerMap();
+		
+		MapNode n_top = map->getNodeNoEx(p+v3s16(0,1,0));
+		if(!ndef->get(n_top).light_propagates ||
+				ndef->get(n_top).isLiquid())
+		{
+			n.setContent(ndef->getId("dirt"));
+			map->addNodeWithEvent(p, n);
+		}
+	}
+};
+
+class SpawnRatsAroundTreesABM : public ActiveBlockModifier
+{
+private:
+public:
+	virtual std::set<std::string> getTriggerContents()
+	{
+		std::set<std::string> s;
+		s.insert("tree");
+		s.insert("jungletree");
+		return s;
+	}
+	virtual float getTriggerInterval()
+	{ return 10.0; }
+	virtual u32 getTriggerChance()
+	{ return 200; }
+	virtual void trigger(ServerEnvironment *env, v3s16 p, MapNode n,
+			u32 active_object_count, u32 active_object_count_wider)
+	{
+		if(active_object_count_wider != 0)
+			return;
+
+		INodeDefManager *ndef = env->getGameDef()->ndef();
+		ServerMap *map = &env->getServerMap();
+		
+		v3s16 p1 = p + v3s16(myrand_range(-2, 2),
+				0, myrand_range(-2, 2));
+		MapNode n1 = map->getNodeNoEx(p1);
+		MapNode n1b = map->getNodeNoEx(p1+v3s16(0,-1,0));
+		if(n1b.getContent() == ndef->getId("dirt_with_grass") &&
+				n1.getContent() == CONTENT_AIR)
+		{
+			v3f pos = intToFloat(p1, BS);
+			ServerActiveObject *obj = new RatSAO(env, pos);
+			env->addActiveObject(obj);
+		}
+	}
+};
+
+static void getMob_dungeon_master(Settings &properties)
+{
+	properties.set("looks", "dungeon_master");
+	properties.setFloat("yaw", 1.57);
+	properties.setFloat("hp", 30);
+	properties.setBool("bright_shooting", true);
+	properties.set("shoot_type", "fireball");
+	properties.set("shoot_y", "0.7");
+	properties.set("player_hit_damage", "1");
+	properties.set("player_hit_distance", "1.0");
+	properties.set("player_hit_interval", "0.5");
+	properties.setBool("mindless_rage", myrand_range(0,100)==0);
+}
+
+class SpawnInCavesABM : public ActiveBlockModifier
+{
+private:
+public:
+	virtual std::set<std::string> getTriggerContents()
+	{
+		std::set<std::string> s;
+		s.insert("stone");
+		s.insert("mossycobble");
+		return s;
+	}
+	virtual float getTriggerInterval()
+	{ return 10.0; }
+	virtual u32 getTriggerChance()
+	{ return 200; }
+	virtual void trigger(ServerEnvironment *env, v3s16 p, MapNode n,
+			u32 active_object_count, u32 active_object_count_wider)
+	{
+		if(active_object_count_wider != 0)
+			return;
+
+		INodeDefManager *ndef = env->getGameDef()->ndef();
+		ServerMap *map = &env->getServerMap();
+
+		v3s16 p1 = p + v3s16(0,1,0);
+		MapNode n1a = map->getNodeNoEx(p1+v3s16(0,0,0));
+		if(n1a.getLightBlend(env->getDayNightRatio(), ndef) <= 3){
+			MapNode n1b = map->getNodeNoEx(p1+v3s16(0,1,0));
+			if(n1a.getContent() == CONTENT_AIR &&
+					n1b.getContent() == CONTENT_AIR)
+			{
+				v3f pos = intToFloat(p1, BS);
+				int i = myrand()%5;
+				if(i == 0 || i == 1){
+					actionstream<<"A dungeon master spawns at "
+							<<PP(p1)<<std::endl;
+					Settings properties;
+					getMob_dungeon_master(properties);
+					ServerActiveObject *obj = new MobV2SAO(
+							env, pos, &properties);
+					env->addActiveObject(obj);
+				} else if(i == 2 || i == 3){
+					actionstream<<"Rats spawn at "
+							<<PP(p1)<<std::endl;
+					for(int j=0; j<3; j++){
+						ServerActiveObject *obj = new RatSAO(
+								env, pos);
+						env->addActiveObject(obj);
+					}
+				} else {
+					actionstream<<"An oerkki spawns at "
+							<<PP(p1)<<std::endl;
+					ServerActiveObject *obj = new Oerkki1SAO(
+							env, pos);
+					env->addActiveObject(obj);
+				}
+			}
+		}
+	}
+};
+
+class MakeTreesFromSaplingsABM : public ActiveBlockModifier
+{
+private:
+public:
+	virtual std::set<std::string> getTriggerContents()
+	{
+		std::set<std::string> s;
+		s.insert("sapling");
+		return s;
+	}
+	virtual float getTriggerInterval()
+	{ return 10.0; }
+	virtual u32 getTriggerChance()
+	{ return 50; }
+	virtual void trigger(ServerEnvironment *env, v3s16 p, MapNode n,
+			u32 active_object_count, u32 active_object_count_wider)
+	{
+		INodeDefManager *ndef = env->getGameDef()->ndef();
+		ServerMap *map = &env->getServerMap();
+		
+		actionstream<<"A sapling grows into a tree at "
+				<<PP(p)<<std::endl;
+
+		core::map<v3s16, MapBlock*> modified_blocks;
+		v3s16 tree_p = p;
+		ManualMapVoxelManipulator vmanip(map);
+		v3s16 tree_blockp = getNodeBlockPos(tree_p);
+		vmanip.initialEmerge(tree_blockp - v3s16(1,1,1), tree_blockp + v3s16(1,1,1));
+		bool is_apple_tree = myrand()%4 == 0;
+		mapgen::make_tree(vmanip, tree_p, is_apple_tree, ndef);
+		vmanip.blitBackAll(&modified_blocks);
+
+		// update lighting
+		core::map<v3s16, MapBlock*> lighting_modified_blocks;
+		for(core::map<v3s16, MapBlock*>::Iterator
+			i = modified_blocks.getIterator();
+			i.atEnd() == false; i++)
+		{
+			lighting_modified_blocks.insert(i.getNode()->getKey(), i.getNode()->getValue());
+		}
+		map->updateLighting(lighting_modified_blocks, modified_blocks);
+
+		// Send a MEET_OTHER event
+		MapEditEvent event;
+		event.type = MEET_OTHER;
+		for(core::map<v3s16, MapBlock*>::Iterator
+			i = modified_blocks.getIterator();
+			i.atEnd() == false; i++)
+		{
+			v3s16 p = i.getNode()->getKey();
+			event.modified_blocks.insert(p, true);
+		}
+		map->dispatchEvent(&event);
+	}
+};
+
+void add_legacy_abms(ServerEnvironment *env, INodeDefManager *nodedef)
+{
+	env->addActiveBlockModifier(new GrowGrassABM());
+	env->addActiveBlockModifier(new RemoveGrassABM());
+	env->addActiveBlockModifier(new SpawnRatsAroundTreesABM());
+	env->addActiveBlockModifier(new SpawnInCavesABM());
+	env->addActiveBlockModifier(new MakeTreesFromSaplingsABM());
+}
+
+
diff --git a/src/content_abm.h b/src/content_abm.h
new file mode 100644
index 000000000..408151233
--- /dev/null
+++ b/src/content_abm.h
@@ -0,0 +1,33 @@
+/*
+Minetest-c55
+Copyright (C) 2011 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 General Public License as published by
+the Free Software Foundation; either version 2 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 General Public License for more details.
+
+You should have received a copy of the GNU 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 CONTENT_ABM_HEADER
+#define CONTENT_ABM_HEADER
+
+class ServerEnvironment;
+class INodeDefManager;
+
+/*
+	Legacy ActiveBlockModifiers
+*/
+
+void add_legacy_abms(ServerEnvironment *env, INodeDefManager *nodedef);
+
+#endif
+
diff --git a/src/environment.cpp b/src/environment.cpp
index 94c88d57c..416657142 100644
--- a/src/environment.cpp
+++ b/src/environment.cpp
@@ -17,6 +17,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
+#include <set>
+#include <list>
+#include <map>
 #include "environment.h"
 #include "filesys.h"
 #include "porting.h"
@@ -296,6 +299,12 @@ ServerEnvironment::~ServerEnvironment()
 
 	// Drop/delete map
 	m_map->drop();
+
+	// Delete ActiveBlockModifiers
+	for(core::list<ActiveBlockModifier*>::Iterator
+			i = m_abms.begin(); i != m_abms.end(); i++){
+		delete (*i);
+	}
 }
 
 void ServerEnvironment::serializePlayers(const std::string &savedir)
@@ -545,56 +554,101 @@ void ServerEnvironment::loadMeta(const std::string &savedir)
 	}
 }
 
-#if 0
-// This is probably very useless
-void spawnRandomObjects(MapBlock *block)
+struct ActiveABM
 {
-	for(s16 z0=0; z0<MAP_BLOCKSIZE; z0++)
-	for(s16 x0=0; x0<MAP_BLOCKSIZE; x0++)
+	ActiveBlockModifier *abm;
+	int chance;
+};
+
+class ABMHandler
+{
+private:
+	ServerEnvironment *m_env;
+	std::map<content_t, std::list<ActiveABM> > m_aabms;
+public:
+	ABMHandler(core::list<ActiveBlockModifier*> &abms,
+			float dtime_s, ServerEnvironment *env):
+		m_env(env)
 	{
-		bool last_node_walkable = false;
-		for(s16 y0=0; y0<MAP_BLOCKSIZE; y0++)
+		infostream<<"ABMHandler: dtime_s="<<dtime_s<<std::endl;
+		if(dtime_s < 0.001)
+			return;
+		INodeDefManager *ndef = env->getGameDef()->ndef();
+		for(core::list<ActiveBlockModifier*>::Iterator
+				i = abms.begin(); i != abms.end(); i++){
+			ActiveBlockModifier *abm = *i;
+			ActiveABM aabm;
+			aabm.abm = abm;
+			float intervals = dtime_s / abm->getTriggerInterval();
+			float chance = abm->getTriggerChance();
+			if(chance == 0)
+				chance = 1;
+			aabm.chance = 1.0 / pow(1.0 / chance, intervals);
+			if(aabm.chance == 0)
+				aabm.chance = 1;
+			std::set<std::string> contents_s = abm->getTriggerContents();
+			for(std::set<std::string>::iterator
+					i = contents_s.begin(); i != contents_s.end(); i++){
+				content_t c = ndef->getId(*i);
+				if(c == CONTENT_IGNORE)
+					continue;
+				std::map<content_t, std::list<ActiveABM> >::iterator j;
+				j = m_aabms.find(c);
+				if(j == m_aabms.end()){
+					std::list<ActiveABM> aabmlist;
+					m_aabms[c] = aabmlist;
+					j = m_aabms.find(c);
+				}
+				j->second.push_back(aabm);
+			}
+		}
+	}
+	void apply(MapBlock *block)
+	{
+		ServerMap *map = &m_env->getServerMap();
+		// Find out how many objects the block contains
+		u32 active_object_count = block->m_static_objects.m_active.size();
+		// Find out how many objects this and all the neighbors contain
+		u32 active_object_count_wider = 0;
+		for(s16 x=-1; x<=1; x++)
+		for(s16 y=-1; y<=1; y++)
+		for(s16 z=-1; z<=1; z++)
 		{
-			v3s16 p(x0,y0,z0);
-			MapNode n = block->getNodeNoEx(p);
-			if(n.getContent() == CONTENT_IGNORE)
-				continue;
-			if(m_gamedef->ndef()->get(n).liquid_type != LIQUID_NONE)
+			MapBlock *block2 = map->getBlockNoCreateNoEx(
+					block->getPos() + v3s16(x,y,z));
+			if(block2==NULL)
 				continue;
-			if(m_gamedef->ndef()->get(n).walkable)
-			{
-				last_node_walkable = true;
+			active_object_count_wider +=
+					block2->m_static_objects.m_active.size()
+					+ block2->m_static_objects.m_stored.size();
+		}
+
+		v3s16 p0;
+		for(p0.X=0; p0.X<MAP_BLOCKSIZE; p0.X++)
+		for(p0.Y=0; p0.Y<MAP_BLOCKSIZE; p0.Y++)
+		for(p0.Z=0; p0.Z<MAP_BLOCKSIZE; p0.Z++)
+		{
+			MapNode n = block->getNodeNoEx(p0);
+			content_t c = n.getContent();
+			v3s16 p = p0 + block->getPosRelative();
+
+			std::map<content_t, std::list<ActiveABM> >::iterator j;
+			j = m_aabms.find(c);
+			if(j == m_aabms.end())
 				continue;
+
+			for(std::list<ActiveABM>::iterator
+					i = j->second.begin(); i != j->second.end(); i++){
+				if(myrand() % i->chance != 0)
+					continue;
+				// Call all the trigger variations
+				i->abm->trigger(m_env, p, n);
+				i->abm->trigger(m_env, p, n,
+						active_object_count, active_object_count_wider);
 			}
-			if(last_node_walkable)
-			{
-				// If block contains light information
-				if(m_gamedef->ndef()->get(n).param_type == CPT_LIGHT)
-				{
-					if(n.getLight(LIGHTBANK_DAY) <= 5)
-					{
-						if(myrand() % 1000 == 0)
-						{
-							v3f pos_f = intToFloat(p+block->getPosRelative(), BS);
-							pos_f.Y -= BS*0.4;
-							ServerActiveObject *obj = new Oerkki1SAO(NULL,0,pos_f);
-							std::string data = obj->getStaticData();
-							StaticObject s_obj(obj->getType(),
-									obj->getBasePosition(), data);
-							// Add one
-							block->m_static_objects.insert(0, s_obj);
-							delete obj;
-							block->raiseModified(MOD_STATE_WRITE_NEEDED,
-									"spawnRandomObjects");
-						}
-					}
-				}
-			}
-			last_node_walkable = false;
 		}
 	}
-}
-#endif
+};
 
 void ServerEnvironment::activateBlock(MapBlock *block, u32 additional_dtime)
 {
@@ -605,10 +659,14 @@ void ServerEnvironment::activateBlock(MapBlock *block, u32 additional_dtime)
 		dtime_s = m_game_time - block->getTimestamp();
 	dtime_s += additional_dtime;
 
-	// Set current time as timestamp (and let it set ChangedFlag)
-	block->setTimestamp(m_game_time);
+	infostream<<"ServerEnvironment::activateBlock(): block timestamp: "
+			<<stamp<<", game time: "<<m_game_time<<std::endl;
+
+	// Set current time as timestamp
+	block->setTimestampNoChangedFlag(m_game_time);
 
-	//infostream<<"Block is "<<dtime_s<<" seconds old."<<std::endl;
+	infostream<<"ServerEnvironment::activateBlock(): block is "
+			<<dtime_s<<" seconds old."<<std::endl;
 	
 	// Activate stored objects
 	activateObjects(block);
@@ -626,36 +684,14 @@ void ServerEnvironment::activateBlock(MapBlock *block, u32 additional_dtime)
 				"node metadata modified in activateBlock");
 	}
 
-	// TODO: Do something
-	// TODO: Implement usage of ActiveBlockModifier
-	
-	// Here's a quick demonstration
-	v3s16 p0;
-	for(p0.X=0; p0.X<MAP_BLOCKSIZE; p0.X++)
-	for(p0.Y=0; p0.Y<MAP_BLOCKSIZE; p0.Y++)
-	for(p0.Z=0; p0.Z<MAP_BLOCKSIZE; p0.Z++)
-	{
-		v3s16 p = p0 + block->getPosRelative();
-		MapNode n = block->getNodeNoEx(p0);
-#if 1
-		// Test something:
-		// Convert all mud under proper day lighting to grass
-		if(n.getContent() == LEGN(m_gamedef->ndef(), "CONTENT_MUD"))
-		{
-			if(dtime_s > 300)
-			{
-				MapNode n_top = block->getNodeNoEx(p0+v3s16(0,1,0));
-				if(m_gamedef->ndef()->get(n_top).light_propagates &&
-						!m_gamedef->ndef()->get(n_top).isLiquid() &&
-						n_top.getLight(LIGHTBANK_DAY, m_gamedef->ndef()) >= 13)
-				{
-					n.setContent(LEGN(m_gamedef->ndef(), "CONTENT_GRASS"));
-					m_map->addNodeWithEvent(p, n);
-				}
-			}
-		}
-#endif
-	}
+	/* Handle ActiveBlockModifiers */
+	ABMHandler abmhandler(m_abms, dtime_s, this);
+	abmhandler.apply(block);
+}
+
+void ServerEnvironment::addActiveBlockModifier(ActiveBlockModifier *abm)
+{
+	m_abms.push_back(abm);
 }
 
 void ServerEnvironment::clearAllObjects()
@@ -748,20 +784,6 @@ void ServerEnvironment::clearAllObjects()
 			<<" in "<<num_blocks_cleared<<" blocks"<<std::endl;
 }
 
-static void getMob_dungeon_master(Settings &properties)
-{
-	properties.set("looks", "dungeon_master");
-	properties.setFloat("yaw", 1.57);
-	properties.setFloat("hp", 30);
-	properties.setBool("bright_shooting", true);
-	properties.set("shoot_type", "fireball");
-	properties.set("shoot_y", "0.7");
-	properties.set("player_hit_damage", "1");
-	properties.set("player_hit_distance", "1.0");
-	properties.set("player_hit_interval", "0.5");
-	properties.setBool("mindless_rage", myrand_range(0,100)==0);
-}
-
 void ServerEnvironment::step(float dtime)
 {
 	DSTACK(__FUNCTION_NAME);
@@ -930,6 +952,11 @@ void ServerEnvironment::step(float dtime)
 			
 			// Set current time as timestamp
 			block->setTimestampNoChangedFlag(m_game_time);
+			// If time has changed much from the one on disk,
+			// set block to be saved when it is unloaded
+			if(block->getTimestamp() > block->getDiskTimestamp() + 60)
+				block->raiseModified(MOD_STATE_WRITE_AT_UNLOAD,
+						"Timestamp older than 60s (step)");
 
 			// Run node metadata
 			bool changed = block->m_node_metadata->step(dtime);
@@ -946,23 +973,15 @@ void ServerEnvironment::step(float dtime)
 		}
 	}
 	
-	if(m_active_blocks_test_interval.step(dtime, 10.0))
+	const float abm_interval = 10.0;
+	if(m_active_block_modifier_interval.step(dtime, abm_interval))
 	{
 		ScopeProfiler sp(g_profiler, "SEnv: modify in blocks avg /10s", SPT_AVG);
-		//float dtime = 10.0;
 		TimeTaker timer("modify in active blocks");
-
-		INodeDefManager *ndef = m_gamedef->ndef();
-		
-		// Pre-fetch content ids for the luge loop
-		content_t c_dirt = ndef->getId("dirt");
-		content_t c_grass = ndef->getId("dirt_with_grass");
-		content_t c_tree = ndef->getId("tree");
-		content_t c_jungletree = ndef->getId("jungletree");
-		content_t c_stone = ndef->getId("stone");
-		content_t c_mossycobble = ndef->getId("mossycobble");
-		content_t c_sapling = ndef->getId("sapling");
 		
+		// Initialize handling of ActiveBlockModifiers
+		ABMHandler abmhandler(m_abms, abm_interval, this);
+
 		for(core::map<v3s16, bool>::Iterator
 				i = m_active_blocks.m_list.getIterator();
 				i.atEnd()==false; i++)
@@ -979,199 +998,8 @@ void ServerEnvironment::step(float dtime)
 			// Set current time as timestamp
 			block->setTimestampNoChangedFlag(m_game_time);
 
-			/*
-				Do stuff!
-
-				Note that map modifications should be done using the event-
-				making map methods so that the server gets information
-				about them.
-
-				Reading can be done quickly directly from the block.
-
-				Everything should bind to inside this single content
-				searching loop to keep things fast.
-			*/
-			// TODO: Implement usage of ActiveBlockModifier
-			
-			// Find out how many objects the block contains
-			//u32 active_object_count = block->m_static_objects.m_active.size();
-			// Find out how many objects this and all the neighbors contain
-			u32 active_object_count_wider = 0;
-			for(s16 x=-1; x<=1; x++)
-			for(s16 y=-1; y<=1; y++)
-			for(s16 z=-1; z<=1; z++)
-			{
-				MapBlock *block = m_map->getBlockNoCreateNoEx(p+v3s16(x,y,z));
-				if(block==NULL)
-					continue;
-				active_object_count_wider +=
-						block->m_static_objects.m_active.size()
-						+ block->m_static_objects.m_stored.size();
-				
-				/*if(block->m_static_objects.m_stored.size() != 0){
-					errorstream<<"ServerEnvironment::step(): "
-							<<PP(block->getPos())<<" contains "
-							<<block->m_static_objects.m_stored.size()
-							<<" stored objects; "
-							<<"when spawning objects, when counting active "
-							<<"objects in wide area. relative position: "
-							<<"("<<x<<","<<y<<","<<z<<")"<<std::endl;
-				}*/
-			}
-
-			v3s16 p0;
-			for(p0.X=0; p0.X<MAP_BLOCKSIZE; p0.X++)
-			for(p0.Y=0; p0.Y<MAP_BLOCKSIZE; p0.Y++)
-			for(p0.Z=0; p0.Z<MAP_BLOCKSIZE; p0.Z++)
-			{
-				v3s16 p = p0 + block->getPosRelative();
-				MapNode n = block->getNodeNoEx(p0);
-
-				/*
-					Test something:
-					Convert dirt under proper lighting to grass
-				*/
-				if(n.getContent() == c_dirt)
-				{
-					if(myrand()%20 == 0)
-					{
-						MapNode n_top = m_map->getNodeNoEx(p+v3s16(0,1,0));
-						if(m_gamedef->ndef()->get(n_top).light_propagates &&
-								!m_gamedef->ndef()->get(n_top).isLiquid() &&
-								n_top.getLightBlend(getDayNightRatio(),
-										m_gamedef->ndef()) >= 13)
-						{
-							n.setContent(c_grass);
-							m_map->addNodeWithEvent(p, n);
-						}
-					}
-				}
-				/*
-					Convert grass into dirt if under something else than air
-				*/
-				if(n.getContent() == c_grass)
-				{
-					//if(myrand()%20 == 0)
-					{
-						MapNode n_top = m_map->getNodeNoEx(p+v3s16(0,1,0));
-						if(!m_gamedef->ndef()->get(n_top).light_propagates ||
-								m_gamedef->ndef()->get(n_top).isLiquid())
-						{
-							n.setContent(c_dirt);
-							m_map->addNodeWithEvent(p, n);
-						}
-					}
-				}
-				/*
-					Rats spawn around regular trees
-				*/
-				if(n.getContent() == c_tree ||
-						n.getContent() == c_jungletree)
-				{
-   					if(myrand()%200 == 0 && active_object_count_wider == 0)
-					{
-						v3s16 p1 = p + v3s16(myrand_range(-2, 2),
-								0, myrand_range(-2, 2));
-						MapNode n1 = m_map->getNodeNoEx(p1);
-						MapNode n1b = m_map->getNodeNoEx(p1+v3s16(0,-1,0));
-						if(n1b.getContent() == c_grass &&
-								n1.getContent() == CONTENT_AIR)
-						{
-							v3f pos = intToFloat(p1, BS);
-							ServerActiveObject *obj = new RatSAO(this, pos);
-							addActiveObject(obj);
-						}
-					}
-				}
-				/*
-					Fun things spawn in caves and dungeons
-				*/
-				if(n.getContent() == c_stone ||
-						n.getContent() == c_mossycobble)
-				{
-   					if(myrand()%200 == 0 && active_object_count_wider == 0)
-					{
-						v3s16 p1 = p + v3s16(0,1,0);
-						MapNode n1a = m_map->getNodeNoEx(p1+v3s16(0,0,0));
-						if(n1a.getLightBlend(getDayNightRatio(),
-								m_gamedef->ndef()) <= 3){
-							MapNode n1b = m_map->getNodeNoEx(p1+v3s16(0,1,0));
-							if(n1a.getContent() == CONTENT_AIR &&
-									n1b.getContent() == CONTENT_AIR)
-							{
-								v3f pos = intToFloat(p1, BS);
-								int i = myrand()%5;
-								if(i == 0 || i == 1){
-									actionstream<<"A dungeon master spawns at "
-											<<PP(p1)<<std::endl;
-									Settings properties;
-									getMob_dungeon_master(properties);
-									ServerActiveObject *obj = new MobV2SAO(
-											this, pos, &properties);
-									addActiveObject(obj);
-								} else if(i == 2 || i == 3){
-									actionstream<<"Rats spawn at "
-											<<PP(p1)<<std::endl;
-									for(int j=0; j<3; j++){
-										ServerActiveObject *obj = new RatSAO(
-												this, pos);
-										addActiveObject(obj);
-									}
-								} else {
-									actionstream<<"An oerkki spawns at "
-											<<PP(p1)<<std::endl;
-									ServerActiveObject *obj = new Oerkki1SAO(
-											this, pos);
-									addActiveObject(obj);
-								}
-							}
-						}
-					}
-				}
-				/*
-					Make trees from saplings!
-				*/
-				if(n.getContent() == c_sapling)
-				{
-					if(myrand()%50 == 0)
-					{
-						actionstream<<"A sapling grows into a tree at "
-								<<PP(p)<<std::endl;
-
-						core::map<v3s16, MapBlock*> modified_blocks;
-						v3s16 tree_p = p;
-						ManualMapVoxelManipulator vmanip(m_map);
-						v3s16 tree_blockp = getNodeBlockPos(tree_p);
-						vmanip.initialEmerge(tree_blockp - v3s16(1,1,1), tree_blockp + v3s16(1,1,1));
-						bool is_apple_tree = myrand()%4 == 0;
-						mapgen::make_tree(vmanip, tree_p, is_apple_tree,
-								m_gamedef->ndef());
-						vmanip.blitBackAll(&modified_blocks);
-
-						// update lighting
-						core::map<v3s16, MapBlock*> lighting_modified_blocks;
-						for(core::map<v3s16, MapBlock*>::Iterator
-							i = modified_blocks.getIterator();
-							i.atEnd() == false; i++)
-						{
-							lighting_modified_blocks.insert(i.getNode()->getKey(), i.getNode()->getValue());
-						}
-						m_map->updateLighting(lighting_modified_blocks, modified_blocks);
-
-						// Send a MEET_OTHER event
-						MapEditEvent event;
-						event.type = MEET_OTHER;
-						for(core::map<v3s16, MapBlock*>::Iterator
-							i = modified_blocks.getIterator();
-							i.atEnd() == false; i++)
-						{
-							v3s16 p = i.getNode()->getKey();
-							event.modified_blocks.insert(p, true);
-						}
-						m_map->dispatchEvent(&event);
-					}
-				}
-			}
+			/* Handle ActiveBlockModifiers */
+			abmhandler.apply(block);
 		}
 
 		u32 time_ms = timer.stop(true);
@@ -1241,60 +1069,6 @@ void ServerEnvironment::step(float dtime)
 		*/
 		removeRemovedObjects();
 	}
-
-	if(g_settings->getBool("enable_experimental"))
-	{
-
-	/*
-		TEST CODE
-	*/
-#if 0
-	m_random_spawn_timer -= dtime;
-	if(m_random_spawn_timer < 0)
-	{
-		//m_random_spawn_timer += myrand_range(2.0, 20.0);
-		//m_random_spawn_timer += 2.0;
-		m_random_spawn_timer += 200.0;
-
-		/*
-			Find some position
-		*/
-
-		/*v2s16 p2d(myrand_range(-5,5), myrand_range(-5,5));
-		s16 y = 1 + getServerMap().findGroundLevel(p2d);
-		v3f pos(p2d.X*BS,y*BS,p2d.Y*BS);*/
-		
-		Player *player = getRandomConnectedPlayer();
-		v3f pos(0,0,0);
-		if(player)
-			pos = player->getPosition();
-		pos += v3f(
-			myrand_range(-3,3)*BS,
-			5,
-			myrand_range(-3,3)*BS
-		);
-
-		/*
-			Create a ServerActiveObject
-		*/
-
-		//TestSAO *obj = new TestSAO(this, pos);
-		//ServerActiveObject *obj = new ItemSAO(this, pos, "CraftItem Stick 1");
-		//ServerActiveObject *obj = new RatSAO(this, pos);
-		//ServerActiveObject *obj = new Oerkki1SAO(this, pos);
-		//ServerActiveObject *obj = new FireflySAO(this, pos);
-
-		infostream<<"Server: Spawning MobV2SAO at "
-				<<"("<<pos.X<<","<<pos.Y<<","<<pos.Z<<")"<<std::endl;
-		
-		Settings properties;
-		getMob_dungeon_master(properties);
-		ServerActiveObject *obj = new MobV2SAO(this, pos, &properties);
-		addActiveObject(obj);
-	}
-#endif
-
-	} // enable_experimental
 }
 
 ServerActiveObject* ServerEnvironment::getActiveObject(u16 id)
diff --git a/src/environment.h b/src/environment.h
index 48e9cfa75..a3418dbd4 100644
--- a/src/environment.h
+++ b/src/environment.h
@@ -30,7 +30,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 	- etc.
 */
 
-#include <list>
+#include <set>
 #include "common_irrlicht.h"
 #include "player.h"
 #include "map.h"
@@ -96,6 +96,29 @@ protected:
 };
 
 /*
+	Active block modifier interface.
+
+	These are fed into ServerEnvironment at initialization time;
+	ServerEnvironment handles deleting them.
+*/
+
+class ActiveBlockModifier
+{
+public:
+	ActiveBlockModifier(){};
+	virtual ~ActiveBlockModifier(){};
+	
+	virtual std::set<std::string> getTriggerContents()=0;
+	virtual float getTriggerInterval() = 0;
+	// chance of (1 / return value), 0 is disallowed
+	virtual u32 getTriggerChance() = 0;
+	// This is called usually at interval for 1/chance of the nodes
+	virtual void trigger(ServerEnvironment *env, v3s16 p, MapNode n){};
+	virtual void trigger(ServerEnvironment *env, v3s16 p, MapNode n,
+			u32 active_object_count, u32 active_object_count_wider){};
+};
+
+/*
 	List of active blocks, used by ServerEnvironment
 */
 
@@ -299,38 +322,14 @@ private:
 	// List of active blocks
 	ActiveBlockList m_active_blocks;
 	IntervalLimiter m_active_blocks_management_interval;
-	IntervalLimiter m_active_blocks_test_interval;
+	IntervalLimiter m_active_block_modifier_interval;
 	IntervalLimiter m_active_blocks_nodemetadata_interval;
 	// Time from the beginning of the game in seconds.
 	// Incremented in step().
 	u32 m_game_time;
 	// A helper variable for incrementing the latter
 	float m_game_time_fraction_counter;
-};
-
-/*
-	Active block modifier interface.
-
-	These are fed into ServerEnvironment at initialization time;
-	ServerEnvironment handles deleting them.
-
-	NOTE: Not used currently (TODO: Use or remove)
-*/
-
-class ActiveBlockModifier
-{
-public:
-	ActiveBlockModifier(){};
-	virtual ~ActiveBlockModifier(){};
-
-	//virtual core::list<u8> update(ServerEnvironment *env) = 0;
-	virtual u32 getTriggerContentCount(){ return 1;}
-	virtual u8 getTriggerContent(u32 i) = 0;
-	virtual float getActiveInterval() = 0;
-	// chance of (1 / return value), 0 is disallowed
-	virtual u32 getActiveChance() = 0;
-	// This is called usually at interval for 1/chance of the nodes
-	virtual void triggerEvent(ServerEnvironment *env, v3s16 p) = 0;
+	core::list<ActiveBlockModifier*> m_abms;
 };
 
 #ifndef SERVER
diff --git a/src/map.cpp b/src/map.cpp
index f1fbc7a1c..0de534f4d 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -2011,7 +2011,7 @@ ServerMap::ServerMap(std::string savedir, IGameDef *gamedef):
 	emergeSector(v2s16(0,0));
 
 	// Initially write whole map
-	save(false);
+	save(MOD_STATE_CLEAN);
 }
 
 ServerMap::~ServerMap()
@@ -2023,7 +2023,7 @@ ServerMap::~ServerMap()
 		if(m_map_saving_enabled)
 		{
 			// Save only changed parts
-			save(true);
+			save(MOD_STATE_WRITE_AT_UNLOAD);
 			infostream<<"Server: saved map to "<<m_savedir<<std::endl;
 		}
 		else
@@ -2324,7 +2324,7 @@ MapBlock* ServerMap::finishBlockMake(mapgen::BlockMakeData *data,
 		Save changed parts of map
 		NOTE: Will be saved later.
 	*/
-	//save(true);
+	//save(MOD_STATE_WRITE_AT_UNLOAD);
 
 	/*infostream<<"finishBlockMake() done for ("<<blockpos.X<<","<<blockpos.Y<<","
 			<<blockpos.Z<<")"<<std::endl;*/
@@ -2832,7 +2832,7 @@ std::string ServerMap::getBlockFilename(v3s16 p)
 	return cc;
 }
 
-void ServerMap::save(bool only_changed)
+void ServerMap::save(ModifiedState save_level)
 {
 	DSTACK(__FUNCTION_NAME);
 	if(m_map_saving_enabled == false)
@@ -2841,11 +2841,11 @@ void ServerMap::save(bool only_changed)
 		return;
 	}
 	
-	if(only_changed == false)
+	if(save_level == MOD_STATE_CLEAN)
 		infostream<<"ServerMap: Saving whole map, this can take time."
 				<<std::endl;
 	
-	if(only_changed == false || m_map_metadata_changed)
+	if(m_map_metadata_changed || save_level == MOD_STATE_CLEAN)
 	{
 		saveMapMeta();
 	}
@@ -2866,7 +2866,7 @@ void ServerMap::save(bool only_changed)
 		ServerMapSector *sector = (ServerMapSector*)i.getNode()->getValue();
 		assert(sector->getId() == MAPSECTOR_SERVER);
 	
-		if(sector->differs_from_disk || only_changed == false)
+		if(sector->differs_from_disk || save_level == MOD_STATE_CLEAN)
 		{
 			saveSectorMeta(sector);
 			sector_meta_count++;
@@ -2881,8 +2881,7 @@ void ServerMap::save(bool only_changed)
 			
 			block_count_all++;
 
-			if(block->getModified() >= MOD_STATE_WRITE_NEEDED 
-					|| only_changed == false)
+			if(block->getModified() >= save_level)
 			{
 				// Lazy beginSave()
 				if(!save_started){
@@ -2909,7 +2908,7 @@ void ServerMap::save(bool only_changed)
 	/*
 		Only print if something happened or saved whole map
 	*/
-	if(only_changed == false || sector_meta_count != 0
+	if(save_level == MOD_STATE_CLEAN || sector_meta_count != 0
 			|| block_count != 0)
 	{
 		infostream<<"ServerMap: Written: "
diff --git a/src/map.h b/src/map.h
index 413a7fc05..2bd2c0eb8 100644
--- a/src/map.h
+++ b/src/map.h
@@ -32,6 +32,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "constants.h"
 #include "voxel.h"
 #include "utility.h" // Needed for UniqueQueue, a member of Map
+#include "modifiedstate.h"
 
 extern "C" {
 	#include "sqlite3.h"
@@ -236,7 +237,7 @@ public:
 	virtual void beginSave() {return;};
 	virtual void endSave() {return;};
 	
-	virtual void save(bool only_changed){assert(0);};
+	virtual void save(ModifiedState save_level){assert(0);};
 	
 	// Server implements this.
 	// Client leaves it as no-op.
@@ -396,7 +397,7 @@ public:
 	void beginSave();
 	void endSave();
 
-	void save(bool only_changed);
+	void save(ModifiedState save_level);
 	//void loadAll();
 	
 	void listAllLoadableBlocks(core::list<v3s16> &dst);
diff --git a/src/mapblock.cpp b/src/mapblock.cpp
index bc678db15..016cb222e 100644
--- a/src/mapblock.cpp
+++ b/src/mapblock.cpp
@@ -48,6 +48,7 @@ MapBlock::MapBlock(Map *parent, v3s16 pos, IGameDef *gamedef, bool dummy):
 		m_day_night_differs(false),
 		m_generated(false),
 		m_timestamp(BLOCK_TIMESTAMP_UNDEFINED),
+		m_disk_timestamp(BLOCK_TIMESTAMP_UNDEFINED),
 		m_usage_timer(0)
 {
 	data = NULL;
@@ -928,10 +929,12 @@ void MapBlock::deSerializeDiskExtra(std::istream &is, u8 version)
 		m_static_objects.deSerialize(is);
 		
 	// Timestamp
-	if(version >= 17)
+	if(version >= 17){
 		setTimestamp(readU32(is));
-	else
+		m_disk_timestamp = m_timestamp;
+	} else {
 		setTimestamp(BLOCK_TIMESTAMP_UNDEFINED);
+	}
 	
 	// Dynamically re-set ids based on node names
 	NameIdMapping nimap;
diff --git a/src/mapblock.h b/src/mapblock.h
index 5b27d01c3..aa5aa43f7 100644
--- a/src/mapblock.h
+++ b/src/mapblock.h
@@ -35,6 +35,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #ifndef SERVER
 	#include "mapblock_mesh.h"
 #endif
+#include "modifiedstate.h"
 
 class Map;
 class NodeMetadataList;
@@ -53,19 +54,6 @@ enum{
 	FACE_LEFT
 };*/
 
-enum ModifiedState
-{
-	// Has not been modified.
-	MOD_STATE_CLEAN = 0,
-	MOD_RESERVED1 = 1,
-	// Has been modified, and will be saved when being unloaded.
-	MOD_STATE_WRITE_AT_UNLOAD = 2,
-	MOD_RESERVED3 = 3,
-	// Has been modified, and will be saved as soon as possible.
-	MOD_STATE_WRITE_NEEDED = 4,
-	MOD_RESERVED5 = 5,
-};
-
 // NOTE: If this is enabled, set MapBlock to be initialized with
 //       CONTENT_IGNORE.
 /*enum BlockGenerationStatus
@@ -167,6 +155,10 @@ public:
 			m_modified = mod;
 			m_modified_reason = reason;
 			m_modified_reason_too_long = false;
+
+			if(m_modified >= MOD_STATE_WRITE_AT_UNLOAD){
+				m_disk_timestamp = m_timestamp;
+			}
 		} else if(mod == m_modified){
 			if(!m_modified_reason_too_long){
 				if(m_modified_reason.size() < 40)
@@ -509,6 +501,10 @@ public:
 	{
 		return m_timestamp;
 	}
+	u32 getDiskTimestamp()
+	{
+		return m_disk_timestamp;
+	}
 	
 	/*
 		See m_usage_timer
@@ -646,6 +642,8 @@ private:
 		Value BLOCK_TIMESTAMP_UNDEFINED=0xffffffff means there is no timestamp.
 	*/
 	u32 m_timestamp;
+	// The on-disk (or to-be on-disk) timestamp value
+	u32 m_disk_timestamp;
 
 	/*
 		When the block is accessed, this is set to 0.
diff --git a/src/modifiedstate.h b/src/modifiedstate.h
new file mode 100644
index 000000000..280b0e092
--- /dev/null
+++ b/src/modifiedstate.h
@@ -0,0 +1,37 @@
+/*
+Minetest-c55
+Copyright (C) 2010 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 General Public License as published by
+the Free Software Foundation; either version 2 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 General Public License for more details.
+
+You should have received a copy of the GNU 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 MODIFIEDSTATE_HEADER
+#define MODIFIEDSTATE_HEADER
+
+enum ModifiedState
+{
+	// Has not been modified.
+	MOD_STATE_CLEAN = 0,
+	MOD_RESERVED1 = 1,
+	// Has been modified, and will be saved when being unloaded.
+	MOD_STATE_WRITE_AT_UNLOAD = 2,
+	MOD_RESERVED3 = 3,
+	// Has been modified, and will be saved as soon as possible.
+	MOD_STATE_WRITE_NEEDED = 4,
+	MOD_RESERVED5 = 5,
+};
+
+#endif
+
diff --git a/src/server.cpp b/src/server.cpp
index 2c892fa8c..bb91749af 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -46,6 +46,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "tooldef.h"
 #include "craftdef.h"
 #include "mapgen.h"
+#include "content_abm.h"
 
 #define PP(x) "("<<(x).X<<","<<(x).Y<<","<<(x).Z<<")"
 
@@ -282,7 +283,7 @@ void * EmergeThread::Thread()
 				MapEditEventIgnorer ign(&m_server->m_ignore_map_edit_events);
 				
 				// Activate objects and stuff
-				m_server->m_env->activateBlock(block, 3600);
+				m_server->m_env->activateBlock(block, 0);
 			}
 		}
 
@@ -1116,6 +1117,11 @@ Server::Server(
 	// Load players
 	infostream<<"Server: Loading players"<<std::endl;
 	m_env->deSerializePlayers(m_mapsavedir);
+
+	/*
+		Add some test ActiveBlockModifiers to environment
+	*/
+	add_legacy_abms(m_env, m_nodedef);
 }
 
 Server::~Server()
@@ -1937,22 +1943,8 @@ void Server::AsyncRunStep()
 			// Map
 			JMutexAutoLock lock(m_env_mutex);
 
-			/*// Unload unused data (delete from memory)
-			m_env->getMap().unloadUnusedData(
-					g_settings->getFloat("server_unload_unused_sectors_timeout"));
-					*/
-			/*u32 deleted_count = m_env->getMap().unloadUnusedData(
-					g_settings->getFloat("server_unload_unused_sectors_timeout"));
-					*/
-
-			// Save only changed parts
-			m_env->getMap().save(true);
-
-			/*if(deleted_count > 0)
-			{
-				infostream<<"Server: Unloaded "<<deleted_count
-						<<" blocks from memory"<<std::endl;
-			}*/
+			// Save changed parts of map
+			m_env->getMap().save(MOD_STATE_WRITE_NEEDED);
 
 			// Save players
 			m_env->serializePlayers(m_mapsavedir);