Allow group:groupname in ABM definition and implement minetest.hash_node_position()

builtin/builtin.lua

@@ -861,6 +861,14 @@ function minetest.get_connected_players()
 	return list
 end
 
+function minetest.hash_node_position(pos)
+	return (pos.z+32768)*65536*65536 + (pos.y+32768)*65536 + pos.x+32768
+end
+
+--
+-- Privileges
+--
+
 minetest.registered_privileges = {}
 function minetest.register_privilege(name, description)
 	minetest.registered_privileges[name] = description

doc/lua_api.txt

@@ -542,6 +542,8 @@ minetest.after(time, func, param)
 
 Random:
 minetest.get_connected_players() -> list of ObjectRefs
+minetest.hash_node_position({x=,y=,z=}) -> 48-bit integer
+^ Gives a unique hash number for a node position (16+16+16=48bit)
 
 Global objects:
 minetest.env - environment reference
@@ -768,6 +770,7 @@ Entity definition (register_entity)
 
 ABM (ActiveBlockModifier) definition (register_abm)
 {
+    -- In the following two fields, also group:groupname will work.
     nodenames = {"default:lava_source"},
     neighbors = {"default:water_source", "default:water_flowing"}, -- (any of these)
      ^ If left out or empty, any neighbor will do

src/environment.cpp

@@ -646,19 +646,21 @@ public:
 					= abm->getRequiredNeighbors();
 			for(std::set<std::string>::iterator
 					i = required_neighbors_s.begin();
-					i != required_neighbors_s.end(); i++){
-				content_t c = ndef->getId(*i);
-				if(c == CONTENT_IGNORE)
-					continue;
-				aabm.required_neighbors.insert(c);
+					i != required_neighbors_s.end(); i++)
+			{
+				ndef->getIds(*i, aabm.required_neighbors);
 			}
 			// Trigger contents
 			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;
+					i = contents_s.begin(); i != contents_s.end(); i++)
+			{
+				std::set<content_t> ids;
+				ndef->getIds(*i, ids);
+				for(std::set<content_t>::const_iterator k = ids.begin();
+						k != ids.end(); k++)
+				{
+					content_t c = *k;
 					std::map<content_t, std::list<ActiveABM> >::iterator j;
 					j = m_aabms.find(c);
 					if(j == m_aabms.end()){
@@ -670,6 +672,7 @@ public:
 				}
 			}
 		}
+	}
 	void apply(MapBlock *block)
 	{
 		if(m_aabms.empty())

src/nodedef.cpp

@@ -380,6 +380,25 @@ public:
 		getId(name, id);
 		return id;
 	}
+	virtual void getIds(const std::string &name, std::set<content_t> &result)
+			const
+	{
+		if(name.substr(0,6) != "group:"){
+			content_t id = CONTENT_IGNORE;
+			if(getId(name, id))
+				result.insert(id);
+			return;
+		}
+		std::string group = name.substr(6);
+		for(u16 id=0; id<=MAX_CONTENT; id++)
+		{
+			const ContentFeatures &f = m_content_features[id];
+			if(f.name == "") // Quickly discard undefined nodes
+				continue;
+			if(itemgroup_get(f.groups, group) != 0)
+				result.insert(id);
+		}
+	}
 	virtual const ContentFeatures& get(const std::string &name) const
 	{
 		content_t id = CONTENT_IGNORE;

src/nodedef.h

@@ -238,6 +238,9 @@ public:
 	virtual const ContentFeatures& get(const MapNode &n) const=0;
 	virtual bool getId(const std::string &name, content_t &result) const=0;
 	virtual content_t getId(const std::string &name) const=0;
+	// Allows "group:name" in addition to regular node names
+	virtual void getIds(const std::string &name, std::set<content_t> &result)
+			const=0;
 	virtual const ContentFeatures& get(const std::string &name) const=0;
 	
 	virtual void serialize(std::ostream &os)=0;
@@ -254,6 +257,9 @@ public:
 	virtual const ContentFeatures& get(const MapNode &n) const=0;
 	virtual bool getId(const std::string &name, content_t &result) const=0;
 	virtual content_t getId(const std::string &name) const=0;
+	// Allows "group:name" in addition to regular node names
+	virtual void getIds(const std::string &name, std::set<content_t> &result)
+			const=0;
 	// If not found, returns the features of CONTENT_IGNORE
 	virtual const ContentFeatures& get(const std::string &name) const=0;