initial commit

subgame + mods

mods/markers/README.md

@@ -0,0 +1,3 @@
+
+This is work in progress.
+

mods/markers/areas.lua

@@ -0,0 +1,833 @@
+
+-- TODO: offer teleport button?
+
+-- taken from mobf
+local COLOR_RED   = "#FF0000";
+local COLOR_GREEN = "#00FF00";
+local COLOR_WHITE = "#FFFFFF";
+
+
+-- we need to store which list we present to which player
+markers.menu_data_by_player = {}
+
+
+markers.get_area_by_pos = function(pos)
+
+   local found_areas = {};
+   for id, area in pairs(areas.areas) do
+      if( pos.x >= area.pos1.x and pos.x <= area.pos2.x and
+          pos.y >= area.pos1.y and pos.y <= area.pos2.y and
+          pos.z >= area.pos1.z and pos.z <= area.pos2.z )then
+
+         area[ 'id' ] = id;
+         table.insert(found_areas, area );
+      end
+   end
+   return found_areas;
+end
+
+
+
+-- mode: can be pos, player, all, subarea, main_areas
+-- mode_data: content depends on mode
+-- selected: display information about the area the player single-clicked on
+markers.get_area_list_formspec = function( player, mode, pos, mode_data, selected )
+
+
+   local id_list = {};
+   local title   = '???';
+   local tlabel  = '';
+
+   -- expects a position in mode_data
+   if(     mode=='pos' ) then
+      -- title would be too long for a label
+      title  = 'All areas which contain position..';
+      tlabel = '<'..minetest.pos_to_string( mode_data )..'>:';
+
+      for id, area in pairs(areas.areas) do
+
+         if( mode_data.x >= area.pos1.x and mode_data.x <= area.pos2.x and
+             mode_data.y >= area.pos1.y and mode_data.y <= area.pos2.y and
+             mode_data.z >= area.pos1.z and mode_data.z <= area.pos2.z )then
+
+            table.insert( id_list, id );
+         end
+      end
+
+   -- expects a playername in mode_data
+   elseif( mode=='player' ) then
+
+      title  = 'All areas owned by player..';
+      tlabel = '<'..tostring( mode_data )..'>:';
+
+      for id, area in pairs(areas.areas) do
+
+         if( area.owner == mode_data ) then
+            table.insert( id_list, id );
+         end
+      end
+
+   -- expects an area_id in mode_data
+   elseif( mode=='subareas' ) then
+
+      title  = 'All subareas of area..';
+      tlabel = '<'..tostring( areas.areas[ mode_data ].name )..'> ['..tostring( mode_data )..']:';
+
+      for id, area in pairs(areas.areas) do
+
+         if( area.parent and area.parent == mode_data ) then
+            table.insert( id_list, id );
+         end
+      end
+
+   -- show only areas that do not have parents
+   elseif( mode=='main_areas' ) then
+      title  = 'All main areas:';
+      tlabel = '*all main areas*';
+      for id, area in pairs(areas.areas) do
+
+         if( not( area.parent )) then
+            table.insert( id_list, id );
+         end
+      end
+ 
+
+   elseif( mode=='all' ) then
+      title  = 'All areas:'; 
+      tlabel = '*all areas*';
+
+      for id, area in pairs(areas.areas) do
+         table.insert( id_list, id );
+      end
+   end
+   
+
+   local formspec = 'size[10,9]';
+
+   title  = minetest.formspec_escape( title );
+   tlabel = minetest.formspec_escape( tlabel );
+
+   formspec = formspec..
+	"label[0.5,0;"..title.."]"..
+	"label[4.7,0;"..tlabel.."]"..
+	"label[0.5,8.5;Doubleclick to select area.]"..
+	"label[4.7,8.5;Areas found: "..tostring( #id_list )..".]"..
+	"textlist[0.5,0.5;7,8;markers_area_list_selection;"; 
+
+   local liste = '';
+   for i,v in ipairs( id_list ) do
+      if( liste ~= '' ) then
+         liste = liste..',';
+      end
+      liste = liste..minetest.formspec_escape( areas:toString( v ) );
+         
+   end
+
+   -- highlight selected entry
+   if( selected ) then
+      formspec = formspec..liste..';'..selected..';false]';
+   else
+      formspec = formspec..liste..';]';
+   end
+   
+   local pname = player:get_player_name();
+   if( not( markers.menu_data_by_player[ pname ] )) then
+      markers.menu_data_by_player[ pname ] = {};
+   end
+
+   -- display information about the location of the area the player clicked on
+   if( selected 
+      and id_list[ selected ]
+      and areas.areas[ id_list[ selected ]] ) then
+
+      local this_area = areas.areas[ id_list[ selected ]];
+
+      local subareas = {};
+      for i,v in pairs( areas.areas ) do
+         if( v.parent and v.parent == id_list[ selected ]) then
+            table.insert( subareas, i );
+         end
+      end
+
+      formspec = formspec..
+               markers.show_compass_marker( 8.5, 3.0, false, pos, this_area.pos1, this_area.pos2 );
+
+
+      if( this_area.parent) then
+         formspec = formspec..
+               'button[8.0,0.5;2,0.5;show_parent;'.. 
+			minetest.formspec_escape( areas.areas[ this_area.parent ].name )..']';
+      end
+
+      if( #subareas > 0 ) then
+         formspec = formspec..
+               'button[8.0,1.0;2,0.5;list_subareas;'..
+                        minetest.formspec_escape( 'List subareas ('..tostring( #subareas )..')')..']';
+      end
+ 
+
+      if( mode=='player' ) then
+         formspec = formspec..
+               'label[8.0,1.5;'..
+			minetest.formspec_escape( this_area.owner..'\'s areas')..']';
+      else
+         formspec = formspec..
+               'button[8.0,1.5;2,0.5;list_player_areas;'..
+			minetest.formspec_escape( this_area.owner..'\'s areas')..']';
+      end
+
+   end
+
+   formspec = formspec..
+               'button[8.0,8.5;2,0.5;list_main_areas;List all main areas]';
+
+   -- we need to remember especially the id_list - else it would be impossible to know what the
+   -- player selected
+   markers.menu_data_by_player[ pname ] = {
+	  typ       = 'area_list',
+          mode      = mode,
+          pos       = pos,
+          mode_data = mode_data,
+          list      = id_list,
+
+	  selected  = id_list[ selected ],
+	};
+         
+	  
+   return formspec;
+end
+
+
+
+
+-- shows a formspec with information about a particular area
+-- pos is the position of the marker stone or place where the player clicked
+--  with the land title register; it is used for relative display of coordinates
+markers.get_area_desc_formspec = function( id, player, pos )
+
+   if( not( areas.areas ) or not( id ) or not( areas.areas[ id ] )) then
+      return 'field[info;Error:;Area not found.]';
+   end
+   local this_area = areas.areas[ id ];
+
+   local pname     = player:get_player_name();
+
+   -- show some buttons only if area is owned by the player
+   local is_owner  = false;
+
+   if( this_area.owner == pname ) then
+      is_owner     = true;
+   end
+
+   local formspec  = 'size[10,9]'..
+	'label[2.5,0.0;Area information and management]'..
+	'button_exit[4.7,7.0;1,0.5;abort;OK]';
+
+   -- general information about the area
+   formspec = formspec..
+	'label[0.5,1.0;This is area number ]'..
+        'label[4.7,1.0;'..tostring( id )..']'..
+
+	'label[0.5,1.5;The area is called ]'..
+        'label[4.7,1.5;'..minetest.formspec_escape( this_area.name or '-not set-')..']'..
+
+	'label[0.5,2.0;It is owned by ]'..
+        'label[4.7,2.0;'..minetest.formspec_escape( this_area.owner)..']';
+
+
+   -- these functions are only available to the owner of the area
+   if( is_owner ) then
+      formspec = formspec..
+        'button_exit[8.0,0.0;2,0.5;change_owner;Change owner]'..
+        'button_exit[8.0,1.0;2,0.5;delete;Delete]'..
+        'button_exit[8.0,1.5;2,0.5;rename;Rename]'..
+        'button_exit[8.0,2.0;2,0.5;list_player_areas;My areas]';
+
+   -- subareas of own areas can be deleted (but not renamed)
+   elseif( not( is_owner )
+      and this_area.parent
+      and areas.areas[ this_area.parent ]
+      and areas.areas[ this_area.parent ].owner == pname ) then
+ 
+      formspec = formspec..
+        'button_exit[8.0,1.0;2,0.5;delete;Delete subarea]'..
+        'button_exit[8.0,2.0;2,0.5;list_player_areas;Player\'s areas]';
+
+   else
+      formspec = formspec..
+        'button_exit[8.0,2.0;2,0.5;list_player_areas;Player\'s areas]';
+   end
+
+
+   -- players with the areas priv get an extra menu
+   if( minetest.check_player_privs(pname, {areas=true})) then
+      formspec = formspec..
+              'label[8.0,6.0;Admin commands:]'..
+        'button_exit[8.0,6.5;2,0.5;change_owner;Change owner]'..
+        'button_exit[8.0,7.0;2,0.5;delete;Delete]'..
+        'button_exit[8.0,7.5;2,0.5;rename;Rename]';
+   end
+
+
+   -- show subowners and areas with the same coordinates
+   formspec = formspec..
+	'label[0.5,2.5;Further owners of the entire area:]';
+   local further_owners = {};
+   for i, area in pairs(areas.areas) do
+      if( i ~= id and
+          this_area.pos1.x == area.pos1.x and this_area.pos2.x == area.pos2.x and
+          this_area.pos1.y == area.pos1.y and this_area.pos2.y == area.pos2.y and
+          this_area.pos1.z == area.pos1.z and this_area.pos2.z == area.pos2.z )then
+
+         table.insert( further_owners, area.owner );
+      end
+   end
+   if( #further_owners > 0 ) then
+
+      formspec = formspec..
+        'label[4.7,2.5;'..minetest.formspec_escape( table.concat( further_owners, ', '))..'.]';
+
+      -- deleting subowners is done by deleting their areas
+      if( is_owner ) then
+         formspec = formspec..
+	        'button_exit[8.0,2.5;2,0.5;add_owner;Add]';
+      end
+   else
+      formspec = formspec..
+        'label[4.7,2.5;-none-]';
+ 
+      if( is_owner ) then
+         formspec = formspec..
+		'button_exit[8.0,2.5;2,0.5;add_owner;Add]';
+      end
+   end  
+
+
+   -- is the area a subarea?
+   if( this_area.parent ) then
+      formspec = formspec..
+	'label[0.5,3.0;This area is a sub-area of area]'..
+	'label[4.7,3.0;'..minetest.formspec_escape( areas.areas[ this_area.parent ].name..' ['..this_area.parent..']' )..']'..
+        'button_exit[8.0,3.0;2,0.5;show_parent;Show main area]';
+   end
+ 
+
+   -- does the area have subareas, i.e. is it a parent area for others?
+   local sub_areas = {};
+   for i, area in pairs(areas.areas) do
+      if( i ~= id and
+          area.parent == id ) then
+
+         table.insert( sub_areas, i );
+      end
+   end
+   if( #sub_areas > 0 ) then
+
+      formspec = formspec..
+	'label[0.5,4.0;Number of defined subareas:]'..
+        'label[4.7,4.0;'..tostring( #sub_areas )..']'..
+        'button_exit[8.0,4.0;2,0.5;list_subareas;List subareas]';
+   else
+      formspec = formspec..
+	'label[0.5,4.0;There are no subareas defined.]';
+   end
+
+
+   -- give information about the size of the area
+   local length_x = (math.abs( this_area.pos2.x - this_area.pos1.x )+1);
+   local length_y = (math.abs( this_area.pos2.y - this_area.pos1.y )+1);
+   local length_z = (math.abs( this_area.pos2.z - this_area.pos1.z )+1);
+
+   formspec = formspec..
+               'label[0.5,4.5;The area extends from]'..
+               'label[4.7,4.5;'..minetest.pos_to_string( this_area.pos1 )..' to '..minetest.pos_to_string( this_area.pos2 )..'.]'..
+               'label[4.7,4.75;It spans '..tostring( length_x )..
+                                   ' x '..tostring( length_z )..
+                                   ' = '..tostring( length_x * length_z )..
+                                   ' m^2. Height: '..tostring( length_y )..' m.]';
+
+
+   formspec = formspec..
+               markers.show_compass_marker( 2.0, 7.0, true, pos, this_area.pos1, this_area.pos2 );
+
+-- TODO: buy / sell button
+
+   local pname = player:get_player_name();
+   if( not( markers.menu_data_by_player[ pname ] )) then
+      markers.menu_data_by_player[ pname ] = {};
+   end
+
+   -- we need to remember especially the id_list - else it would be impossible to know what the
+   -- player selected
+   markers.menu_data_by_player[ pname ] =
+	{ typ       = 'show_area',
+          mode      = nil, 
+          pos       = pos,
+          mode_data = nil,
+          list      = nil,
+
+	  selected  = id,
+	};
+         
+   return formspec;
+end
+
+
+
+-- shows where the area (defined by pos1/pos2) is located relative to the given position pos
+-- row_offset/col_offset are offsets for the formspec
+markers.show_compass_marker = function( col_offset, row_offset, with_text, pos, pos1, pos2 )
+
+   local formspec = '';
+-- TODO: show up/down information somehow
+-- TODO: what if checked with a land claim register?
+
+   -- if possible, show how far the area streches into each direction relative to pos
+   if(     pos.x >= pos1.x and pos.x <= pos2.x 
+       and pos.y >= pos1.y and pos.y <= pos2.y 
+       and pos.z >= pos1.z and pos.z <= pos2.z ) then
+ 
+      if( with_text ) then
+         formspec = formspec..
+		'label[0.5,5.5;Dimensions of the area in relation to..]'..
+-- TODO: check if there is a marker; else write 'position you clicked on'
+		'label[4.7,5.5;the marker at '..minetest.pos_to_string( pos )..':]'..
+		'button_exit[8.0,5.5;2,0.5;list_areas_at;Local areas]';
+      end
+      formspec = formspec..
+		'image['..col_offset..','..row_offset..';1,1;markers_stone.png]'..
+		'label['..(col_offset-0.8)..','..(row_offset+0.05)..';'..tostring( pos.x - pos1.x         )..' m W]'..
+		'label['..(col_offset+1.0)..','..(row_offset+0.05)..';'..tostring(         pos2.x - pos.x )..' m E]'..
+		'label['..(col_offset+0.1)..','..(row_offset+0.80)..';'..tostring( pos.z - pos1.z         )..' m S]'..
+		'label['..(col_offset+0.1)..','..(row_offset-0.80)..';'..tostring(         pos2.z - pos.z )..' m N]';
+
+   -- else show how far the area is away
+   else
+
+      local starts_north = '';
+      local starts_south = '';
+      local starts_east  = '';
+      local starts_west  = '';
+      if( pos.z > pos2.z ) then
+         starts_north = '';
+         starts_south = tostring( pos.z - pos2.z         )..' m S';
+      else
+         starts_north = tostring(         pos1.z - pos.z )..' m N';
+         starts_south = '';
+      end
+      if( pos.x > pos2.x ) then
+         starts_east  = '';
+         starts_west  = tostring( pos.x - pos2.x         )..' m W';
+      else
+         starts_east  = tostring(         pos1.x - pos.x )..' m E';
+         starts_west  = '';
+      end
+
+
+      if( with_text ) then
+         formspec = formspec..
+		'label[0.5,5.5;Position of the area in relation to..]'..
+-- TODO: check if there is a marker; else write 'position you clicked on'
+		'label[4.7,5.5;the marker at '..minetest.pos_to_string( pos )..':]'..
+		'button_exit[8.0,5.5;2,0.5;list_areas_at;Local areas]';
+      end
+      formspec = formspec..
+		'image['..col_offset..','..row_offset..';1,1;compass_side_top.png]'..
+		'label['..(col_offset-0.8)..','..(row_offset+0.05)..';'..starts_west..']'..
+		'label['..(col_offset+1.0)..','..(row_offset+0.05)..';'..starts_east..']'..
+		'label['..(col_offset+0.1)..','..(row_offset-0.80)..';'..starts_north..']'..
+		'label['..(col_offset+0.1)..','..(row_offset+0.80)..';'..starts_south..']';
+   end
+ 
+   return formspec;
+end
+
+
+
+-- formspec input needs to be handled diffrently
+markers.form_input_handler_areas = function( player, formname, fields)
+
+   local pname = player:get_player_name();
+
+   if( formname ~= "markers:info"
+      or not( player )
+      or not(  markers.menu_data_by_player[ pname ] )) then
+   
+      return false;
+   end
+  
+   local menu_data = markers.menu_data_by_player[ pname ];
+   local formspec = '';
+
+
+   -- rename an area
+   if( fields.rename 
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ]
+          and areas.areas[ menu_data.selected ].owner == pname ) then
+   
+      local area = areas.areas[ menu_data.selected ];
+      if( not( area.name )) then
+         area.name = '-enter area name-';
+      end
+      formspec = 'field[rename_new_name;Enter new name for area:;'..minetest.formspec_escape( area.name )..']';
+
+   elseif( fields.rename_new_name 
+          and menu_data.selected
+          and  areas.areas[ menu_data.selected ]
+          and ((areas.areas[ menu_data.selected ].owner == pname ) 
+            or minetest.check_player_privs(pname, {areas=true}))) then
+   
+      local area = areas.areas[ menu_data.selected ];
+
+      -- actually rename the area
+      areas.areas[ menu_data.selected ].name = fields.rename_new_name;
+      areas:save();
+
+      minetest.chat_send_player( pname, 'Area successfully renamed.');
+      -- shwo the renamed area
+      formspec = markers.get_area_desc_formspec( menu_data.selected, player, menu_data.pos );
+ 
+
+   
+   -- change owner the area
+   elseif( fields.change_owner
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ] ) then
+   
+      -- there are no checks here - those happen when the area is transferred
+      local area = areas.areas[ menu_data.selected ];
+      formspec = 'field[change_owner_name;Give area \"'..minetest.formspec_escape( area.name )..'\" to player:;-enter name of NEW OWNER-]';
+
+   elseif( fields.change_owner_name
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ] ) then
+
+      local area = areas.areas[ menu_data.selected ];
+
+      -- only own areas can be transfered to another player (or if the areas priv is there)
+      if( area.owner ~= pname 
+        and not( minetest.check_player_privs(pname, {areas=true}))) then
+ 
+         minetest.chat_send_player( pname, 'Permission denied. You do not own the area.');
+
+      elseif( not( areas:player_exists( fields.change_owner_name ))) then
+
+         minetest.chat_send_player( pname, 'That player does not exist.');
+
+      else
+         -- actually change the owner
+         areas.areas[ menu_data.selected ].owner = fields.change_owner_name;
+         areas:save()
+
+         minetest.chat_send_player( pname, 'Your area '..tostring( area.name )..' has been transfered to '..tostring( fields.change_owner_name )..'.');
+
+         minetest.chat_send_player( fields.change_owner_name, pname..'" has given you control over an area.')
+      end
+
+      formspec = markers.get_area_desc_formspec( menu_data.selected, player, menu_data.pos );
+
+
+   -- add an owner to the entire area
+   elseif( fields.add_owner
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ]
+          and areas.areas[ menu_data.selected ].owner == pname ) then
+   
+      local area = areas.areas[ menu_data.selected ];
+      formspec = 'field[add_owner_name;Grant access to area \"'..minetest.formspec_escape( area.name )..'\" to player:;-enter player name-]';
+
+   elseif( fields.add_owner_name 
+              -- the player has to own the area already; we need a diffrent name here
+          and fields.add_owner_name ~= pname
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ]
+          and areas.areas[ menu_data.selected ].owner == pname ) then
+
+      local area = areas.areas[ menu_data.selected ];
+
+      -- does the player exist?
+      if( not( areas:player_exists( fields.add_owner_name ))) then
+         minetest.chat_send_player( pname, 'That player does not exist.');
+         -- show the formspec
+         formspec = markers.get_area_desc_formspec( menu_data.selected, player, menu_data.pos );
+
+      else
+         -- log the creation of the new area
+         minetest.log("action", pname.." runs /add_owner through the markers-mod. Owner = "..fields.add_owner_name..
+                                " AreaName = "..area.name.." ParentID = "..menu_data.selected..
+                                " StartPos = "..area.pos1.x..","..area.pos1.y..","..area.pos1.z..
+                                " EndPos = "  ..area.pos2.x..","..area.pos2.y..","..area.pos2.z)
+
+         -- take the name from the old/parent area
+         local new_id = areas:add( fields.add_owner_name, area.name, area.pos1, area.pos2, menu_data.selected );
+         areas:save()
+
+
+         minetest.chat_send_player( fields.add_owner_name,
+                                "You have been granted control over area #"..
+                                new_id..". Type /list_areas to show your areas.")
+
+         minetest.chat_send_player( pname, 'The player may now build and dig in your area.');
+         -- shwo the new area
+         markers.menu_data_by_player[ pname ].selected = new_id;
+         formspec = markers.get_area_desc_formspec( new_id, player, menu_data.pos );
+      end
+
+
+
+   -- delete area
+   elseif( fields.delete 
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ] ) then
+
+      local area = areas.areas[ menu_data.selected ];
+
+      -- a player can only delete own areas or subareas of own areas
+      if( area.owner ~= pname 
+        and not(     area.parent 
+                 and areas.areas[ area.parent ] 
+                 and areas.areas[ area.parent ].owner
+                 and areas.areas[ area.parent ].owner == pname )
+        and not( minetest.check_player_privs(pname, {areas=true}))) then
+ 
+         minetest.chat_send_player( pname, 'Permission denied. You own neither the area itshelf nor its parent area.');
+         -- shwo the area where the renaming failed
+         formspec = markers.get_area_desc_formspec( menu_data.selected, player, menu_data.pos );
+
+      else
+
+         formspec = 'field[rename_new_name;Enter new name for area:;'..minetest.formspec_escape( area.name )..']';
+         formspec = 'field[delete_confirm;'..minetest.formspec_escape( 'Really delete area \"'..area.name..
+                            '\" (owned by '..area.owner..')? Confirm with YES:')..';-type yes in capitals to confirm-]';
+
+      end
+
+   elseif( fields.delete_confirm 
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ] ) then
+   
+      local area = areas.areas[ menu_data.selected ];
+      local old_owner = area.owner;
+
+      local subareas = {};
+      for i,v in pairs( areas.areas ) do
+         if( v.parent and v.parent == menu_data.selected ) then
+            table.insert( subareas, i );
+         end
+      end
+
+      -- a player can only delete own areas or subareas of own areas
+      if( area.owner ~= pname 
+        and not(     area.parent 
+                 and areas.areas[ area.parent ] 
+                 and areas.areas[ area.parent ].owner
+                 and areas.areas[ area.parent ].owner == pname )
+        and not( minetest.check_player_privs(pname, {areas=true}))) then
+ 
+         minetest.chat_send_player( pname, 'Permission denied. You own neither the area itshelf nor its parent area.');
+         -- shwo the renamed area
+         formspec = markers.get_area_desc_formspec( menu_data.selected, player, menu_data.pos );
+
+      -- avoid accidents
+      elseif( fields.delete_confirm ~= 'YES' ) then
+         minetest.chat_send_player( pname, 'Delition of area \"'..tostring( area.name )..'\" (owned by '..old_owner..') aborted.');
+         formspec = markers.get_area_desc_formspec( menu_data.selected, player, menu_data.pos );
+
+      -- only areas without subareas can be deleted
+      elseif( #subareas > 0 ) then 
+         minetest.chat_send_player( pname, 'The area has '..tostring( #subareas )..' subarea(s). Please delete those first!');
+         formspec = markers.get_area_desc_formspec( menu_data.selected, player, menu_data.pos );
+
+      else
+
+         minetest.chat_send_player( pname, 'Area \"'..tostring( area.name )..'\" (owned by '..old_owner..') deleted.');
+         -- really delete
+         areas:remove( menu_data.selected, false ); -- no recursive delete
+         areas:save();
+         -- show the list of areas owned by the previous owner
+         formspec = markers.get_area_list_formspec( player, 'player',   menu_data.pos, old_owner, nil );
+      end
+
+   
+
+   elseif( fields.show_parent 
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ]
+          and areas.areas[ menu_data.selected ].parent ) then
+
+      formspec = markers.get_area_desc_formspec( areas.areas[ menu_data.selected ].parent, player, menu_data.pos );
+
+
+   elseif( fields.list_player_areas
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ] ) then
+
+      formspec = markers.get_area_list_formspec( player, 'player',   menu_data.pos, areas.areas[ menu_data.selected ].owner, nil );
+
+
+   elseif( fields.list_subareas
+          and menu_data.selected
+          and areas.areas[ menu_data.selected ] ) then
+
+      formspec = markers.get_area_list_formspec( player, 'subareas', menu_data.pos, menu_data.selected, nil );
+
+
+   elseif( fields.list_main_areas ) then
+
+      formspec = markers.get_area_list_formspec( player, 'main_areas', menu_data.pos, nil, nil );
+          
+   elseif( fields.list_areas_at
+          and menu_data.pos ) then
+
+      formspec = markers.get_area_list_formspec( player, 'pos',      menu_data.pos, menu_data.pos, nil );
+
+
+   elseif( fields.markers_area_list_selection
+          and menu_data.typ
+          and menu_data.typ == 'area_list'
+          and menu_data.list
+          and #menu_data.list > 0 ) then
+
+
+      local field_data = fields.markers_area_list_selection:split( ':' );
+      if( not( field_data ) or #field_data < 2 ) then
+         field_data = { '', '' };
+      end
+
+      local selected = tonumber( field_data[ 2 ] );
+      if( field_data[1]=='DCL' ) then
+
+         -- on doubleclick, show detailed area information
+         formspec = markers.get_area_desc_formspec( tonumber( menu_data.list[ selected ] ), player, menu_data.pos );
+      else
+
+         -- on single click, just show the position of that particular area
+         formspec = markers.get_area_list_formspec( player, menu_data.mode, menu_data.pos, menu_data.mode_data, selected );
+      end
+
+   else
+      return false;
+   end
+
+
+   minetest.show_formspec( pname, "markers:info", formspec )
+   return true;
+end
+
+
+
+-- search the area at the given position pos that might be of most intrest to the player
+markers.show_marker_stone_formspec = function( player, pos )
+
+   local pname       = player:get_player_name();
+
+   -- this table stores the list the player may have selected from; at the beginning, there is no list 
+   if( not( markers.menu_data_by_player[ pname ]  )) then
+      markers.menu_data_by_player[ pname ] = {
+	  typ       = 'area_list',
+          mode      = 'main_areas',
+          pos       = pos,
+          mode_data = pos,
+          list      = {},
+
+	  selected  = nil,
+      };
+   end
+
+
+   local formspec        = '';
+
+   local found_areas     = {};
+   local min_area_size   = 100000000000;
+
+   for id, area in pairs(areas.areas) do
+      if( pos.x >= area.pos1.x and pos.x <= area.pos2.x and
+          pos.y >= area.pos1.y and pos.y <= area.pos2.y and
+          pos.z >= area.pos1.z and pos.z <= area.pos2.z )then
+
+         -- ignore y (height) value because some areas may go from bottom to top
+         local area_size = math.abs( area.pos2.x - area.pos1.x )
+                         * math.abs( area.pos2.z - area.pos1.z );
+
+         -- collect subareas that have the same size
+         if( area_size == min_area_size ) then
+            table.insert(found_areas, id );
+         -- we have found a smaller area - that is more intresting here
+         elseif( area_size <= min_area_size ) then
+            found_areas = {};
+            min_area_size = area_size;
+            table.insert(found_areas, id );
+         end
+      end
+   end
+
+   -- no areas found; display error message and selection menu
+   if(     #found_areas < 1 ) then
+
+      formspec = 'size[4,3]'..
+ 		'label[0.5,0.5;This position is not protected.]'..
+		     'button[1.0,1.5;2,0.5;list_main_areas;List all main areas]'..
+		'button_exit[3.0,1.5;1,0.5;abort;OK]';
+ 
+   -- found exactly one areaa - display it
+   elseif( #found_areas == 1 ) then
+
+      formspec = markers.get_area_desc_formspec( found_areas[ 1 ], player, pos );
+
+   -- found more than one area; we have saved only those with the smallest size
+   else
+
+      local own_area    = 0;
+      local parent_area = 0;
+      local upper_area  = 0;
+      for i,v in ipairs( found_areas ) do
+
+         local area = areas.areas[ v ];
+
+         -- owned by player?
+         if(          area.owner == pname ) then
+            own_area    = v;
+
+         -- parentless area?
+         elseif( not( area.parent )) then
+            parent_area = v;
+
+         -- the parent has diffrent coordinates?
+         elseif(      areas.areas[ area.parent ].pos1.x ~= area.pos1.x
+                   or areas.areas[ area.parent ].pos1.y ~= area.pos1.y
+                   or areas.areas[ area.parent ].pos1.z ~= area.pos1.z
+                   or areas.areas[ area.parent ].pos2.x ~= area.pos2.x
+                   or areas.areas[ area.parent ].pos2.y ~= area.pos2.y
+                   or areas.areas[ area.parent ].pos2.z ~= area.pos2.z ) then
+            upper_area = v;
+         end
+      end
+
+      -- the area owned by the player is most intresting
+      if(     own_area    > 0 ) then
+
+         formspec = markers.get_area_desc_formspec( own_area,    player, pos );
+
+      -- if the player owns none of these areas, show the topmost (parentless) area
+      elseif( parent_area > 0 ) then
+
+         formspec = markers.get_area_desc_formspec( parent_area, player, pos );
+
+      -- an area which has a parent with diffrent coordinates from its child may (or may not) be the
+      -- parent of all these subareas we've found here; there is no guarantee, but it's a best guess.
+      -- If it is not good enough, then the player can still search for himshelf.
+      elseif( upper_area  > 0 ) then
+
+         formspec = markers.get_area_desc_formspec( upper_area,  player, pos );
+
+      -- our superficial analysis of the structure of the areas failed; it is up to the player to
+      -- find out which of the candidates he is intrested in; we list them all
+      else
+
+        formspec = markers.get_area_list_formspec( player, 'pos', pos, pos, nil );
+      end
+   end
+
+   minetest.show_formspec( player:get_player_name(), "markers:info", formspec );
+end

mods/markers/depends.txt

@@ -0,0 +1 @@
+areas

mods/markers/init.lua

@@ -0,0 +1,612 @@
+
+-- markers are useful for measuring distances and for marking areas
+-- markers are protected from digging by other players for one day
+-- (the protection for the *marker* auto-expires then, and it can be digged)
+
+markers = {}
+
+-- stores up to 4 marker positions for each player
+markers.positions = {}
+
+-- store the positions of that many markers for each player (until server restart)
+markers.MAX_MARKERS  = 10;
+ 
+-- the protection against digging of the marker by other players expires after this time
+markers.EXPIRE_AFTER = 60*60*24;
+
+-- self-protected areas can not get higher than 100 blocks
+markers.MAX_HEIGHT   = 100;
+
+-- only areas up to this size (in square meters) can be protected
+markers.MAX_SIZE     = 1024; -- 32m * 32m = 1024 m^2
+
+
+dofile(minetest.get_modpath("markers").."/areas.lua");
+
+dofile(minetest.get_modpath("markers").."/marker_stone.lua");
+
+dofile(minetest.get_modpath("markers").."/land_title_register.lua");
+
+
+-- returns the first area found
+markers.get_area_by_pos1_pos2 = function(pos1, pos2)
+   for id, area in pairs(areas.areas) do
+
+      if( ((area.pos1.x == pos1.x and area.pos1.z == pos1.z )
+        or (area.pos1.x == pos1.x and area.pos1.z == pos2.z )
+        or (area.pos1.x == pos2.x and area.pos1.z == pos1.z )
+        or (area.pos1.x == pos2.x and area.pos1.z == pos2.z ))
+
+       and((area.pos2.x == pos1.x and area.pos2.z == pos1.z )
+        or (area.pos2.x == pos1.x and area.pos2.z == pos2.z )
+        or (area.pos2.x == pos2.x and area.pos2.z == pos1.z )
+        or (area.pos2.x == pos2.x and area.pos2.z == pos2.z ))) then
+
+          -- at least pos1 needs to have a hight value that fits in
+          if(  (area.pos1.y <= pos1.y and area.pos2.y >= pos1.y)
+            or (area.pos1.y >= pos1.y and area.pos2.y <= pos1.y)) then
+
+             local found = area;
+             found[ 'id' ] = id;
+             return found;
+
+          end
+      end
+   end
+   return nil;
+end
+
+
+
+
+
+
+-- this function is supposed to return a text string describing the price of the land between po1 and pos2
+-- You can return somethiing like "for free" or "the promise to build anything good" as well as any
+-- real prices in credits or materials - it's really just a text here.
+-- Make sure you do not charge the player more than what you ask here.
+markers.calculate_area_price_text = function( pos1, pos2, playername )
+
+   local price = ( math.abs( pos1.x - pos2.x )+1 )
+               * ( math.abs( pos1.z - pos2.z )+1 );
+
+--               * math.ceil( ( math.abs( pos1.y - pos2.y )+1 )/10);
+
+   return tostring( price )..' credits';
+end
+
+
+
+
+markers.marker_placed = function( pos, placer, itemstack )
+ 
+   if( not( pos ) or not( placer )) then
+      return;
+   end
+ 
+   local meta = minetest.env:get_meta( pos );
+   local name = placer:get_player_name();
+
+   meta:set_string( 'infotext', 'Marker at '..minetest.pos_to_string( pos )..
+				' (placed by '..tostring( name )..'). '..
+				'Right-click to update.');
+   meta:set_string( 'owner',    name );
+   -- this allows protection of this particular marker to expire
+   meta:set_string( 'time',     tostring( os.time()) );
+
+   local txt = '';
+
+   if( not( markers.positions[ name ] ) or #markers.positions[name]<1) then
+      markers.positions[ name ] = {};
+      markers.positions[ name ][ 1 ] = pos;
+ 
+      minetest.chat_send_player( name,
+		'First marker set to position '..
+		minetest.pos_to_string( markers.positions[ name ][ 1 ] )..
+		'. Please place a second marker to measure distance. '..
+		'Place four markers in a square to define an area.');
+   else
+      table.insert( markers.positions[ name ], pos );
+
+      local n = #markers.positions[ name ];
+
+      local dx = markers.positions[ name ][ n ].x - markers.positions[ name ][ n-1 ].x;
+      local dy = markers.positions[ name ][ n ].y - markers.positions[ name ][ n-1 ].y;
+      local dz = markers.positions[ name ][ n ].z - markers.positions[ name ][ n-1 ].z;
+
+      local dir_name = "unknown";
+      local d = 0;
+      if(     dx == 0 and dz > 0 )             then dir_name = "north"; d = math.abs(dz);
+      elseif( dx == 0 and dz < 0 )             then dir_name = "south"; d = math.abs(dz);
+      elseif( dz == 0 and dx > 0 )             then dir_name = "east";  d = math.abs(dx);
+      elseif( dz == 0 and dx < 0 )             then dir_name = "west";  d = math.abs(dx);
+      elseif( dx == 0 and dz == 0 and dy > 0 ) then dir_name = "above"; d = math.abs(dy);
+      elseif( dx == 0 and dz == 0 and dy < 0 ) then dir_name = "below"; d = math.abs(dy);
+      else
+
+         local area   =        (math.abs( dx )+1)
+                             * (math.abs( dz )+1);
+         local volume = area * (math.abs( dy )+1);
+
+         minetest.chat_send_player( name, 'This marker is at '..
+               minetest.pos_to_string( markers.positions[ name ][ n ] )..', while the last one is at '..
+               minetest.pos_to_string( markers.positions[ name ][ n-1 ] )..'. Distance (x/y/z): '..
+               tostring(math.abs(dx))..'/'..
+               tostring(math.abs(dy))..'/'..
+               tostring(math.abs(dz))..
+              '. Area: '..tostring( area )..' m^2. Volume: '..tostring( volume )..' m^3.');
+      end
+     
+      -- this marker is aligned to the last one
+      if( d > 0 ) then
+         minetest.chat_send_player( name, 'Marker placed at '..minetest.pos_to_string( pos )..
+				'. Relative to the marker you placed before, this one is '..
+ 				tostring( d )..' m '..dir_name..'.');
+      end
+
+      -- do the last 4 markers placed form an area?
+      if( #markers.positions[ name ] > 3 ) then
+         local count_x_coord = {};
+         local count_z_coord = {};
+         local anz_x_coord   = 0;
+         local anz_z_coord   = 0;
+         local check_failed  = 0;
+         for i=0,3 do
+
+            local v = markers.positions[ name ][ n-i ].x;
+
+            if( not( count_x_coord[ v ] )) then
+               count_x_coord[       v ] = 1;
+               anz_x_coord = anz_x_coord + 1;
+            elseif(  count_x_coord[ v ] == 2 ) then               
+               check_failed = 1;
+            else
+               count_x_coord[       v ] = count_x_coord[ v ] + 1;
+            end
+
+            v = markers.positions[ name ][ n-i ].z;
+            if( not( count_z_coord[ v ] )) then
+               count_z_coord[       v ] = 1;
+               anz_z_coord = anz_z_coord + 1;
+            elseif(  count_z_coord[ v ] == 2 ) then               
+               check_failed = 1;
+            else
+               count_z_coord[       v ] = count_z_coord[ v ] + 1;
+            end
+         end
+
+         if(     anz_x_coord == 2 
+            and  anz_z_coord == 2
+            and check_failed == 0 ) then
+               
+            minetest.chat_send_player( name, 'The last four markers you placed form a rectangle. '..
+                   'Right-click on this marker here in order to protect the area.');
+         end
+      end
+
+      -- make sure the list does not grow too large
+      if( n > markers.MAX_MARKERS ) then
+         table.remove( markers.positions[ name ], 1 );
+      end
+   end
+end
+
+
+
+markers.marker_can_dig = function(pos,player) 
+
+   if( not( pos ) or not( player )) then
+      return true;
+   end
+
+   local meta  = minetest.env:get_meta( pos );
+   local owner = meta:get_string( 'owner' );
+   local time  = meta:get_string( 'time' ); 
+
+   -- can the marker be removed?
+   if( not( owner ) 
+       or owner==''
+       or not( time ) 
+       or time==''
+       or (os.time() - tonumber( time )) > markers.EXPIRE_AFTER ) then
+
+      return true;
+
+   -- marker whose data got lost anyway
+   elseif( not( markers.positions[ owner ] )
+            or #markers.positions[ owner ] < 1 ) then
+   
+     return true;
+
+   -- marker owned by someone else and still in use
+   elseif( owner ~= player:get_player_name()) then
+
+      minetest.chat_send_player( player:get_player_name(),
+		'Sorry, this marker belongs to '..tostring( owner )..
+		'. If you still want to remove it, try again in '..
+		( tostring( markers.EXPIRE_AFTER + tonumber( time ) - os.time()))..' seconds.');
+      return false;
+
+   end
+  
+   return true;
+end
+
+
+
+
+markers.marker_after_dig_node = function(pos, oldnode, oldmetadata, digger)
+
+   if( not(oldmetadata ) or not(oldmetadata['fields'])) then
+      return;
+   end
+
+   local owner = oldmetadata['fields']['owner'];
+   if( not( owner ) 
+       or owner==''
+       or not( markers.positions[ owner ] )
+       or     #markers.positions[ owner ] < 1 ) then
+
+      return;
+   end
+
+   -- remove the markers position from our table of stored positions
+   local found = 0;
+   for i,v in ipairs( markers.positions[ owner ] ) do
+      if(   v.x == pos.x 
+        and v.y == pos.y
+        and v.z == pos.z ) then
+         found = i;
+      end
+   end
+   if( found ~= 0 ) then
+      table.remove( markers.positions[ owner ], found );
+   end
+   return true;
+end
+
+
+
+
+
+
+markers.get_marker_formspec = function(player, pos, error_msg)
+   local formspec = "";
+
+   local meta  = minetest.env:get_meta( pos );
+   local owner = meta:get_string( 'owner' );
+
+   local name  = player:get_player_name();
+
+   local formspec_info = "size[6,4]"..
+             "button_exit[2,2.5;1,0.5;abort;OK]"..
+             "textarea[1,1;4,2;info;Information;";
+   if( owner ~= nil and owner ~= '' and owner ~= name ) then
+      return formspec_info.."This marker\ncan only be used by\n"..tostring( owner )..", who\nplaced the markers.]";
+   end
+
+   if( not( markers.positions[ name ]) or #markers.positions[name]<1) then
+      return formspec_info.."Information about the positions\nof your other markers\ngot lost.\nPlease dig and place\nyour markers again!]";
+   end
+
+   local n = #markers.positions[ name ];
+
+   if(    markers.positions[ name ][ n ].x ~= pos.x
+      or  markers.positions[ name ][ n ].y ~= pos.y
+      or  markers.positions[ name ][ n ].z ~= pos.z ) then
+
+      return formspec_info.."Please use the marker\nyou placed last\n"..
+                 "for accessing this menu.\nYou can find said marker at\n"..
+                 minetest.pos_to_string( markers.positions[ name ][ n ] )..'.]';
+   end
+
+   if( n < 4 ) then
+      return formspec_info.."Please place 4 markers\n - one in each corner\n of your area - first.]";
+   end
+
+
+   local coords_raw = meta:get_string( 'coords' );
+   local coords      = {};
+   if( coords_raw ~= nil and coords_raw ~= '' ) then
+      coords = minetest.deserialize( coords_raw );
+   end
+   
+
+   local opposite = n;
+   -- the last 4 markers placed ought to form the area
+   if( true or #coords ~= 2 ) then -- TODO
+  
+
+      for i=1,3 do
+
+         -- if both coordinates are diffrent, then this may be the opposite marker
+         if(   ( markers.positions[ name ][ n-i ].x ~=  
+                 markers.positions[ name ][ n   ].x )
+           and ( markers.positions[ name ][ n-i ].z ~=  
+                 markers.positions[ name ][ n   ].z )) then 
+
+             opposite = n-i;
+             coords = { markers.positions[ name ][ n   ],
+                        markers.positions[ name ][ n-i ] };
+         end
+      end
+
+      -- check if they fit
+      for i=1,3 do
+
+         if(not( ((n-i) == opposite )
+             or not(markers.positions[ name ][ n-i ] )
+             or  ( markers.positions[ name ][ n-i ].x == coords[ 1 ].x
+               and markers.positions[ name ][ n-i ].z == coords[ 2 ].z )
+             or  ( markers.positions[ name ][ n-i ].x == coords[ 2 ].x
+               and markers.positions[ name ][ n-i ].z == coords[ 1 ].z ))) then
+
+            return formspec_info.."Error: The last 4 markers\nyou placed do not form\na rectangle.]";
+         end
+
+      end
+
+      -- save data     
+      meta:set_string( 'coords', minetest.serialize( coords ) );
+   end
+
+   -- the coordinates are set; we may present an input form now
+
+    -- has the area already been defined?
+    local area = markers.get_area_by_pos1_pos2( coords[1], coords[2] );
+
+
+    local size = (math.abs( coords[1].x - coords[2].x )+1) 
+               * (math.abs( coords[1].z - coords[2].z )+1);
+
+    -- check if area is too large
+    if( markers.MAX_SIZE < size ) then
+       return formspec_info.."Error: You can only protect\nareas of up to "..tostring( markers.MAX_SIZE ).."m^2.\n"..
+                             "Your marked area is "..tostring( size ).." m^2 large.]";
+    end
+
+    local formspec = 'size[10,7]'..
+               'label[0.5,1;The area you marked extends from]'..
+               'label[4.7,1;'..minetest.pos_to_string( coords[ 1 ] )..' to '..minetest.pos_to_string( coords[ 2 ] )..'.]'..
+               'label[4.7,1.5;It spans '..tostring( math.abs( coords[1].x - coords[2].x )+1 )..
+                               ' x '..tostring( math.abs( coords[1].z - coords[2].z )+1 )..
+                               ' = '..tostring( size )..' m^2.]';
+
+    -- display the error message (if there is any)
+    if( error_msg ~= nil ) then
+       formspec = formspec..
+                    'label[0.5,0.0;Error: ]'..
+                    'textarea[5.0,0;4,1.5;info;;'..error_msg..']';
+    end
+      
+    if( area and area['id'] ) then
+       formspec =   formspec..
+                    'label[0.5,2.0;This is area number ]'..
+                    'label[4.7,2.0;'..tostring( area['id'] )..'.]'..
+                    'label[0.5,2.5;It is owned by ]'..
+                    'label[4.7,2.5;'..tostring( area['owner'] )..'.]'..
+                    'label[0.5,3.0;The area is called ]'..
+                    'label[4.7,3.0;'..tostring( area['name'] )..'.]'..
+                    "button_exit[2,6.0;2,0.5;abort;OK]";
+    else
+       formspec =   formspec..
+                    'label[0.5,2.0;Buying this area will cost you ]'..
+                    'label[4.7,2.0;'..markers.calculate_area_price_text( coords[1], coords[2], name )..'.]'..
+
+                    'label[0.5,3.0;Your area ought to go..]'..
+                    'label[0.5,3.5;this many blocks up:]'..
+                    'field[5.0,4.0;1,0.5;add_height;;40]'..
+                    'label[6.0,3.5;(relative to this marker)]'..
+
+                    'label[0.5,4.0;and this many blocks down:]'..
+                    'field[5.0,4.5;1,0.5;add_depth;;10]'..
+                    'label[6.0,4.0;(relative to this marker)]'..
+
+                    'label[0.5,4.5;The area shall be named]'..
+                    'field[5.0,5.0;6,0.5;set_area_name;;please enter a name]'..
+     
+                    "button_exit[2,6.0;2,0.5;abort;Abort]"..
+                    -- code the position in the "Buy area" field
+                    "button_exit[6,6.0;2,0.5;"..minetest.pos_to_string(pos)..";Buy area]";
+    end
+
+   return formspec;
+end
+
+
+
+-- protect/buy an area
+markers.marker_on_receive_fields = function(pos, formname, fields, sender)
+
+   if( not( pos )) then
+      minetest.chat_send_player( name, 'Sorry, could not find the marker you where using to access this formspec.' );
+      return;
+   end
+
+
+   local meta  = minetest.env:get_meta( pos );
+
+   local name  = sender:get_player_name();
+
+   local coords_string = meta:get_string( 'coords' );
+   if( not( coords_string ) or coords_string == '' ) then
+      minetest.chat_send_player( name, 'Could not find marked area. Please dig and place your markers again!');
+      return;
+   end
+   local coords = minetest.deserialize( coords_string );
+
+
+   -- do not protect areas twice
+   local area = markers.get_area_by_pos1_pos2( coords[1], coords[2] );
+   if( area ) then
+
+      minetest.chat_send_player( name, 'This area is already protected.');
+      return;
+   end
+
+
+   -- check input
+   local add_height = tonumber( fields['add_height'] );
+   local add_depth  = tonumber( fields['add_depth']  );
+
+   local error_msg = '';
+   if(     not( add_height ) or add_height < 0 or add_height > markers.MAX_HEIGHT ) then
+      minetest.chat_send_player( name, 'Please enter a number between 0 and '..tostring( markers.MAX_HEIGHT )..
+		' in the field where the height of your area is requested. Your area will stretch that many blocks '..
+		'up into the sky from the position of this marker onward.');
+      error_msg = 'The height value\nhas to be larger than 0\nand smaller than '..tostring( markers.MAX_HEIGHT );
+     
+   elseif( not( add_depth  ) or add_depth  < 0 or add_depth  > markers.MAX_HEIGHT ) then
+      minetest.chat_send_player( name, 'Please enter a number between 0 and '..tostring( markers.MAX_HEIGHT )..
+		' in the field where the depth of your area is requested. Your area will stretch that many blocks '..
+		'into the ground from the position of this marker onward.');
+      error_msg = 'The depth value\nhas to be larger than 0\nand smaller than '..tostring( markers.MAX_HEIGHT );
+
+   elseif( add_height + add_depth > markers.MAX_HEIGHT ) then
+      minetest.chat_send_player( name,  'Sorry, your area exceeds the height limit. Height and depth added have to '..
+		'be smaller than '..tostring( markers.MAX_HEIGHT )..'.');
+      error_msg = 'height + depth has to\nbe smaller than '..tostring( markers.MAX_HEIGHT )..'.'
+
+   elseif( not( fields[ 'set_area_name' ] ) or fields['set_area_name'] == 'please enter a name' ) then
+      minetest.chat_send_player( name, 'Please provide a name for your area, i.e. \"'..
+		tostring( name )..'s first house\" The name ought to describe what you intend to build here.');
+      error_msg = 'Please provide a\nname for your area!';
+
+   else
+      error_msg = nil;
+   end
+ 
+
+   if( error_msg ~= nil ) then
+      minetest.show_formspec( name, "markers:mark", markers.get_marker_formspec(sender, pos, error_msg));
+      return;
+   end
+
+
+   -- those coords lack the height component
+   local pos1 = coords[1];
+   local pos2 = coords[2];
+   -- apply height values from the formspeck
+   pos1.y = pos.y + add_height;
+   pos2.y = pos.y - add_depth;
+
+   pos1, pos2 = areas:sortPos( pos1, pos2 );
+
+   --minetest.chat_send_player('singleplayer','INPUT: '..minetest.serialize( pos1  )..' pos2: '..minetest.serialize( pos2 ));
+   minetest.log("action", "[markers] /protect invoked, owner="..name..
+                                " areaname="..fields['set_area_name']..
+                                " startpos="..minetest.pos_to_string(pos1)..
+                                " endpos="  ..minetest.pos_to_string(pos2));
+
+   local canAdd, errMsg = areas:canPlayerAddArea(pos1, pos2, name)
+   if not canAdd then
+      minetest.chat_send_player(name, "You can't protect that area: "..errMsg)
+      minetest.show_formspec( name, "markers:mark", markers.get_marker_formspec(sender, pos, errMsg));
+      return
+   end
+
+   local id = areas:add(name, fields['set_area_name'], pos1, pos2, nil)
+   areas:save()
+
+   minetest.chat_send_player(name, "Area protected. ID: "..id)
+
+   minetest.show_formspec( name, "markers:mark", markers.get_marker_formspec(sender, pos, nil));
+end
+
+
+
+-- formspec input needs to be handled diffrently
+markers.form_input_handler = function( player, formname, fields)
+
+   if( formname == "markers:mark" ) then
+
+
+      if( not(fields) or fields['abort']) then
+         return true;
+      end
+
+      --- decode the position of the marker (which is hidden in the Buy-buttons name
+      local pos = {};
+      for k, v in pairs( fields ) do
+         if( v == 'Buy area' ) then
+            pos = minetest.string_to_pos( k );
+         end
+      end
+      if( pos and pos.x and pos.y and pos.z ) then
+         markers.marker_on_receive_fields(pos, formname, fields, player);
+      end
+      return true;
+
+
+   elseif( formname == "markers:info"
+      and player
+      and markers.menu_data_by_player[ player:get_player_name() ] ) then
+
+      local res = markers.form_input_handler_areas( player, formname, fields);
+      if( res ) then
+         return true;
+      end
+  
+      -- TODO
+--      minetest.chat_send_player('singleplayer','MARKERS:INFO WITH '..minetest.serialize( fields ));
+
+   else
+      -- TODO
+--      minetest.chat_send_player('singleplayer','YOU CALLED '..tostring( formname )..' WITH '..minetest.serialize( fields ));
+
+   end
+   
+   return false;
+
+end
+
+minetest.register_on_player_receive_fields( markers.form_input_handler)
+
+
+
+
+minetest.register_node("markers:mark", {
+	description = "Marker",
+	tiles = {"markers_mark.png"},
+	drawtype = "nodebox",
+	paramtype = "light",
+	paramtype2 = "facedir",
+	groups = {snappy=2,choppy=2,dig_immediate=3},
+	light_source = 1,
+	node_box = {
+		type = "fixed",
+		fixed = {
+			{ -0.1, -0.5, -0.1, 0.1, 1.5, 0.1 },
+			},
+		},
+
+        after_place_node = function(pos, placer, itemstack)
+           markers.marker_placed( pos, placer, itemstack );
+        end,
+  
+        -- the node is digged immediately, so we may as well do all the work in can_dig (any wrong digs are not that critical)
+        can_dig = function(pos,player) 
+           return markers.marker_can_dig( pos, player );
+        end,
+
+        after_dig_node = function(pos, oldnode, oldmetadata, digger)
+           return markers.marker_after_dig_node( pos, oldnode, oldmetadata, digger );
+        end,
+
+	on_rightclick = function(pos, node, clicker)
+
+           minetest.show_formspec( clicker:get_player_name(),
+				   "markers:mark",
+				   markers.get_marker_formspec(clicker, pos, nil)
+			);
+	end,
+})
+
+
+minetest.register_craft({
+   output = "markers:mark 4",
+   recipe = { { "group:stick" },
+              { "default:apple" },
+              { "group:stick" },
+             } });
+

mods/markers/land_title_register.lua

@@ -0,0 +1,74 @@
+
+
+minetest.register_tool( "markers:land_title_register",
+{
+    description = "Land title register. Left-click with it to get information about who owns the land you clicked on.",
+    groups = {}, 
+    inventory_image = "default_book.png", -- TODO
+    wield_image = "",
+    wield_scale = {x=1,y=1,z=1},
+    stack_max = 1, -- there is no need to have more than one
+    liquids_pointable = true, -- ground with only water on can be owned as well
+    -- the tool_capabilities are completely irrelevant here - no need to dig
+    tool_capabilities = {
+        full_punch_interval = 1.0,
+        max_drop_level=0,
+        groupcaps={
+            fleshy={times={[2]=0.80, [3]=0.40}, maxwear=0.05, maxlevel=1},
+            snappy={times={[2]=0.80, [3]=0.40}, maxwear=0.05, maxlevel=1},
+            choppy={times={[3]=0.90}, maxwear=0.05, maxlevel=0}
+        }
+    },
+    node_placement_prediction = nil,
+
+    on_place = function(itemstack, placer, pointed_thing)
+
+       if( placer == nil or pointed_thing == nil) then
+          return itemstack; -- nothing consumed
+       end
+       local name = placer:get_player_name();
+
+       -- the position is what we're actually looking for
+       local pos  = minetest.get_pointed_thing_position( pointed_thing, 0 ); --under );
+       
+       if( not( pos ) or not( pos.x )) then
+          minetest.chat_send_player( name, "Position not found.");
+          return itemstack;
+       end
+
+       -- this function shows the formspec with the information about the area(s)
+       markers.show_marker_stone_formspec( placer, pos );
+
+       return itemstack; -- nothing consumed, nothing changed
+    end,
+     
+
+    on_use = function(itemstack, placer, pointed_thing)
+
+       if( placer == nil or pointed_thing == nil) then
+          return itemstack; -- nothing consumed
+       end
+       local name = placer:get_player_name();
+
+       local pos  = minetest.get_pointed_thing_position( pointed_thing, under );
+       
+       if( not( pos ) or not( pos.x )) then
+          minetest.chat_send_player( name, "Position not found.");
+          return itemstack;
+       end
+
+       -- this function shows the formspec with the information about the area(s)
+       markers.show_marker_stone_formspec( placer, pos );
+
+       return itemstack; -- nothing consumed, nothing changed
+    end,
+})
+
+
+minetest.register_craft({
+   output = "markers:land_title_register",
+   recipe = { { "markers:mark" },
+              { "markers:stone" },
+              { "default:book"}
+             } });
+

mods/markers/marker_stone.lua

@@ -0,0 +1,24 @@
+
+minetest.register_node("markers:stone", {
+	description = "Boundary marker for land administration",
+	tiles = {"markers_stone.png", "markers_stone.png", "markers_stone_side.png",
+                "markers_stone_side.png", "markers_stone_side.png", "markers_stone_side.png" },
+-- no facedir here - we want a fixed north indication!
+--	paramtype2 = "facedir",
+	groups = {cracky=2},
+	legacy_facedir_simple = true,
+	is_ground_content = false,
+
+	on_rightclick = function(pos, node, clicker)
+
+           markers.show_marker_stone_formspec( clicker, pos );
+	end,
+})
+
+
+minetest.register_craft({
+   output = "markers:stone",
+   recipe = { { "markers:mark" },
+              { "default:cobble" },
+             } });
+