first commit

README.md

@@ -0,0 +1,6 @@
+Markers
+
+When you place a marker, it will tell you the distance to the last marker
+you placed.
+If you have already two markers placed and place a third one, the first marker
+placed will disappear (if possible, that is, if the area is loaded).

init.lua

@@ -0,0 +1,152 @@
+
+marker = {}
+
+-- can store two positions for each player
+marker.positions = {}
+
+
+marker.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 );
+
+   local txt = '';
+
+   if( not( marker.positions[ name ] )) then
+      marker.positions[ name ] = {};
+      marker.positions[ name ][ 1 ] = pos;
+      marker.positions[ name ][ 2 ] = pos; -- make sure the table has always two entries
+      marker.positions[ name ][ 3 ] = 1;   -- one marker set
+ 
+      minetest.chat_send_player( name, 'First marker set to position '..minetest.pos_to_string( marker.positions[ name ][ 1 ] )..
+                                       '. Please place a second marker to define an area.');
+   else
+      -- remove the node at the old position if possible; if not, it will just sit there until someone digs it
+
+      -- if two nodes have been set already, remove the old one if possible
+      if(  marker.positions[ name ][ 3 ] > 1 ) then
+
+         local old_node = minetest.env:get_node( marker.positions[ name ][ 1 ] );
+         -- is that node loaded and does it contain a marker? If so, remove the old one
+         if( old_node and old_node.name ~= 'ignore' and old_node.name == 'marker:marker' ) then
+            -- actually remove the old marker
+            minetest.env:set_node( marker.positions[ name ][ 1 ], {name='air'} );
+            -- return the old marker to the players inventory
+            placer:get_inventory():add_item("main", "marker:marker 1");
+            minetest.chat_send_player( name, 'Removing now obsolete old marker at '..minetest.pos_to_string( marker.positions[ name ][ 1 ] )..'.');
+         else
+            minetest.chat_send_player( name, 'Warning: Your old marker at '..minetest.pos_to_string( marker.positions[ name ][ 1 ] )..
+                     ' is now obsolete. It could not be removed automaticly. Please do so manually!');
+         end
+      end
+
+      marker.positions[ name ][ 1 ] = marker.positions[ name ][ 2 ];
+      marker.positions[ name ][ 2 ] = pos;
+      marker.positions[ name ][ 3 ] = 2;   -- both markers set
+   end
+
+   local area   =        (math.abs( marker.positions[ name ][ 1 ].x - marker.positions[ name ][ 2 ].x )+1)
+                       * (math.abs( marker.positions[ name ][ 1 ].z - marker.positions[ name ][ 2 ].z )+1);
+   local volume = area * (math.abs( marker.positions[ name ][ 1 ].y - marker.positions[ name ][ 2 ].y )+1);
+
+   minetest.chat_send_player( name, 'Markers set to '..minetest.pos_to_string( marker.positions[ name ][ 1 ] )..' and '..
+                                                                minetest.pos_to_string( marker.positions[ name ][ 2 ] )..'. Distance: '..
+                                     ' x: '..tostring( math.abs(marker.positions[ name ][ 2 ].x - marker.positions[ name ][ 1 ].x))..
+                                    ', y: '..tostring( math.abs(marker.positions[ name ][ 2 ].y - marker.positions[ name ][ 1 ].y))..
+                                    ', z: '..tostring( math.abs(marker.positions[ name ][ 2 ].z - marker.positions[ name ][ 1 ].z))..
+                                    '. Area covered: '..tostring( area )..' m^2. Volume covered: '..tostring( volume )..' m^3.');
+
+end
+
+
+
+marker.marker_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' );
+   -- can the marker be removed?
+   if( not( owner ) 
+       or owner=='' 
+       or not( marker.positions[ owner ] )
+       or (       owner == player:get_player_name()
+          and  ( marker.positions[ owner ][ 1 ].x ~= pos.x 
+              or marker.positions[ owner ][ 1 ].y ~= pos.y 
+              or marker.positions[ owner ][ 1 ].z ~= pos.z )
+          and  ( marker.positions[ owner ][ 2 ].x ~= pos.x 
+              or marker.positions[ owner ][ 2 ].y ~= pos.y 
+              or marker.positions[ owner ][ 2 ].z ~= pos.z ))) then
+
+      minetest.chat_send_player( player:get_player_name(), 'Thank you for cleaning up this leftover marker!');
+      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 is still in use by '..tostring( owner )..'.');
+      return false;
+
+   -- the marker marked pos1
+   elseif (      marker.positions[ owner ][ 1 ].x == pos.x 
+             and marker.positions[ owner ][ 1 ].y == pos.y 
+             and marker.positions[ owner ][ 1 ].z == pos.z ) then
+
+      
+      -- if this was already the last marker
+      if( marker.positions[ owner ][ 3 ] == 1 ) then
+         marker.positions[ owner ] = nil;
+         minetest.chat_send_player( owner, 'Removed your last marker.');
+      else
+         marker.positions[ owner ][ 1 ] = marker.positions[ owner ][ 2 ];
+         marker.positions[ owner ][ 3 ] = 1;   -- only one marker left
+         minetest.chat_send_player( owner, 'Your remaining marker is at '..minetest.pos_to_string( marker.positions[ owner ][ 1 ] )..'.');
+     end
+     return true;
+   
+   -- the marker marked pos2
+   elseif (      marker.positions[ owner ][ 2 ].x == pos.x 
+             and marker.positions[ owner ][ 2 ].y == pos.y 
+             and marker.positions[ owner ][ 2 ].z == pos.z ) then
+
+      
+      -- if this was already the last marker
+      if( marker.positions[ owner ][ 3 ] == 1 ) then
+         marker.positions[ owner ] = nil;
+         minetest.chat_send_player( 'Removed your last marker.');
+      else
+         marker.positions[ owner ][ 2 ] = marker.positions[ owner ][ 1 ];
+         marker.positions[ owner ][ 3 ] = 1;   -- only one marker left
+         minetest.chat_send_player( owner, 'Your remaining marker is at '..minetest.pos_to_string( marker.positions[ owner ][ 1 ] )..'.');
+     end
+     return true;
+
+   end
+end
+
+
+minetest.register_node("marker:marker", {
+	description = "Marker",
+	tiles = {"marker_marker.png"},
+	groups = {snappy=2,choppy=2,dig_immediate=3},
+	light_source = 15,
+
+        after_place_node = function(pos, placer, itemstack)
+           marker.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 marker.marker_dig( pos, player );
+        end
+})
+