refactored (generalized) connected-search code. Added aux1 connected-group mining for stones and territory markers, and added flood-fill placement behavior for territory markers, with aux1 as an override to always place one.

rules.lua

@@ -25,14 +25,10 @@ local solid_drawtypes = {
     glasslike_framed = true,
 }
 
-local S = ("S"):byte(1)
-local W = ("W"):byte(1)
-local E = ("E"):byte(1)
-local C = ("C"):byte(1)
-
-
 --[[
-E: empty
+E: air
+E_: other empty
+Etype: territory marker of some type
 Stype: a go stone of some type
 W: full block wall
 WE0-WE3: edge concrete
@@ -40,6 +36,11 @@ WC0-WC3: corner concrete
 --]]
 local function _check_position_uncached(pos)
     local node = minetest.get_node(pos)
+
+    if node.name == "air" then
+        return "E"
+    end
+
     local reg_item = minetest.registered_items[node.name]
 
     if not reg_item then
@@ -50,6 +51,10 @@ local function _check_position_uncached(pos)
         return "S" .. reg_item.go_team
     end
 
+    if reg_item.groups and reg_item.groups.go_territory_marker then
+        return "E" .. reg_item.go_team
+    end
+
     if reg_item.pattern_def then
         if reg_item.pattern_def.name == "edgy" then
             return "WE" .. node.param2
@@ -61,7 +66,7 @@ local function _check_position_uncached(pos)
     if solid_drawtypes[reg_item.drawtype] and not reg_item.groups.falling_node then
         return "W"
     else
-        return "E"
+        return "E_"
     end
 end
 
@@ -80,8 +85,8 @@ end
 local function edge_check(pos, dir, terminate)
     local under = check_position(pos + down)
 
-    if under:byte(1) == W and under:len() == 3 then
+    if under:sub(1, 1) == "W" and under:len() == 3 then
-        local corner = (under:byte(2) == C)
+        local corner = (under:sub(2, 2) == "C")
         local edge_dir = tonumber(under:sub(3, 3))
 
         if (dir == edge_dir) or (corner and (dir == (edge_dir+1)%4)) then
@@ -106,7 +111,7 @@ local function neighbor_dirs(pos)
     local neighbors = {}
     for i,v in pairs(directions) do
         if not edge_check(pos, i) then
-            if not (check_position(pos + directions[i]):byte(1) == W) then
+            if check_position(pos + directions[i]):sub(1, 1) ~= "W" then
                 neighbors[#neighbors+1] = i
             end
         end
@@ -115,16 +120,11 @@ local function neighbor_dirs(pos)
     return neighbors
 end
 
---[[
+local function connected_search(pos, final_result, early_termination_filter)
-Scans for a connected group, until enumerating the whole group, or
-finding a liberty.  Returns list of captured nodes, or empty list if
-no captures.
---]]
-local function check_captures(pos)
     local group = {pos}
     local stones = {[minetest.hash_node_position(pos)] = pos}
     local checked = {}
-    local team = check_position(pos):sub(2,-1)
+    local piece = check_position(pos)
 
     local probe = 0
     while probe < #group do
@@ -138,10 +138,14 @@ local function check_captures(pos)
             if (not stones[newhash]) and (not checked[newhash]) then
                 local newnode = check_position(newpos)
 
-                if newnode:byte(1) == E then
+                local filter_result
-                    return {capture = false, stones = stones}
+                if early_termination_filter then
-                elseif newnode:byte(1) == S and
+                    filter_result = early_termination_filter(newnode)
-                        newnode:sub(2, -1) == team then
+                end
+                if filter_result then
+                    filter_result.stones = stones
+                    return filter_result
+                elseif newnode == piece then
                     stones[newhash] = newpos
                     group[#group+1] = newpos
                 else
@@ -151,7 +155,61 @@ local function check_captures(pos)
         end
     end
 
-    return {capture = true, stones = stones}
+    final_result = final_result()
+    final_result.stones = stones
+    return final_result
+end
+
+local function _check_captures_filter(node)
+    if node:sub(1, 1) == "E" then
+        return {capture = false}
+    end
+end
+
+local function _check_captures_final()
+    return {capture = true}
+end
+
+local function check_captures(pos)
+    return connected_search(pos, _check_captures_final, _check_captures_filter)
+end
+
+local function _connected_group_final()
+    return {}
+end
+
+local function connected_group(pos)
+    return connected_search(pos, _connected_group_final)
+end
+
+local function territory_search(pos, max)
+    if check_position(pos) ~= "E" then
+        return {}
+    end
+
+    local team
+    return connected_search(pos,
+            function()
+                return {team = team}
+            end,
+            function(node)
+                if node == "E" then
+                    max = max - 1
+                    if max <= 0 then
+                        return {}
+                    end
+                elseif node ~= "E_" and ((node:sub(1, 1) == "E") or (node:sub(1, 1) == "S")) and node:len() > 1 then
+                    node = node:sub(2, -1)
+                    if team then
+                        if team ~= node then
+                            return {}
+                        end
+                    else
+                        team = node
+                    end
+                end
+            end
+    )
 end
 
 function lc_liberties.handle_placement(pos)
@@ -160,7 +218,7 @@ function lc_liberties.handle_placement(pos)
     --nodecore.node_sound(pos, "dug")
 
     local our_stone = check_position(pos)
-    if not (our_stone:byte(1) == S) then
+    if our_stone:sub(1, 1) ~= "S" then
         return
     end
     our_stone = our_stone:sub(2, -1)
@@ -181,7 +239,7 @@ function lc_liberties.handle_placement(pos)
 
         if not checked then
             local node = check_position(new_pos)
-            if (node:byte(1) == S) and (not (node:sub(2, -1) == our_stone)) then
+            if (node:sub(1, 1) == "S") and (node:sub(2, -1) ~= our_stone) then
                 local captures = check_captures(new_pos)
                 captured = captured or captures.capture
                 captureses[#captureses+1] = captures
@@ -226,4 +284,39 @@ function lc_liberties.handle_placement(pos)
     end
 end
 
+function lc_liberties.handle_territory_fill(itemstack, placer, pointed_thing)
+    cache = {}
+
+    if placer.get_player_control and placer:get_player_control().aux1 then
+        return minetest.item_place(itemstack, placer, pointed_thing)
+    end
+
+    if pointed_thing and pointed_thing.above then
+        local territories = territory_search(pointed_thing.above, itemstack:get_count())
+        if territories.team then
+            local piece = modname .. ":territory_" .. territories.team
+            local count = 0
+            for i, v in pairs(territories.stones) do
+                nodecore.set_loud(v, {name = piece})
+                count = count + 1
+            end
+            itemstack:set_count(itemstack:get_count() - count)
+        end
+    end
+
+    return itemstack
+end
+
+function lc_liberties.handle_dig(pos, node, digger)
+    cache = {}
+
+    if digger.get_player_control and digger:get_player_control().aux1 then
+        for i, v in pairs(connected_group(pos).stones) do
+            minetest.node_dig(v, node, digger)
+        end
 
+        return true
+    else
+        return minetest.node_dig(pos, node, digger)
+    end
+end

stones.lua

@@ -68,7 +68,9 @@ local function reg(name, basename, basedef)
 
         sounds = basedef.sounds,
 
-        on_construct = lc_liberties.handle_placement
+        on_construct = lc_liberties.handle_placement,
+
+        on_dig = lc_liberties.handle_dig,
     })
 
     local territory_name = modname .. ":territory_" .. string_lower(name)
@@ -103,11 +105,16 @@ local function reg(name, basename, basedef)
             snappy = 1,
             falling_node = 1,
             falling_repose = 1,
+            go_territory_marker = 1,
         },
 
         go_team = name,
 
         sounds = basedef.sounds,
+
+        on_place = lc_liberties.handle_territory_fill,
+
+        on_dig = lc_liberties.handle_dig,
     })
 
     nodecore.register_craft({