node categorization code to identify go stones, physical walls, empty spaces, and also semantically-meaningful concrete variants

rules.lua

@@ -11,27 +11,61 @@ local modname = minetest.get_current_modname()
 
 local cache = {}
 
-local relativeNeighbors = {
+local relative_neighbors = {
     vector.new(1, 0, 0),
     vector.new(0, 0, 1),
     vector.new(-1, 0, 0),
     vector.new(0, 0, -1)
 }
 
+local solid_drawtypes = {
+    normal = true,
+    glasslike_framed = true,
+}
+
+--[[
+E: empty
+Stype: a go stone of some type
+W: full block wall
+WE0-WE3: edge concrete
+WC0-WC3: corner concrete
+--]]
 function check_position(pos)
     local hash = minetest.hash_node_position(pos)
     if cache[hash] then
         return cache[hash]
     end
 
-    local ret = minetest.get_node(pos)
-    print_r(ret)
-    print_r(minetest.registered_items[ret.name])
-    print(pos)
+    local ret = _check_position_uncached(pos)
+    print(ret) -- todo: remove this
     cache[hash] = ret
     return ret
 end
 
+function _check_position_uncached(pos)
+    local node = minetest.get_node(pos)
+
+    local reg_item = minetest.registered_items[node.name]
+
+    if reg_item.groups and reg_item.groups.go_stone then
+        return "S" .. reg_item.go_team
+    end
+
+    if reg_item.pattern_def then
+        if reg_item.pattern_def.name == "edgy" then
+            return "WE" .. node.param2
+        elseif reg_item.pattern_def.name == "corny" then
+            return "WC" .. node.param2
+        end
+    end
+
+    if solid_drawtypes[reg_item.drawtype] then
+        return "W"
+    else
+        return "E"
+    end
+end
+
 function check_captures(pos)
     minetest.chat_send_all(tostring(pos))
     nodecore.node_sound(pos, "dug")
@@ -40,7 +74,7 @@ function check_captures(pos)
 
     local neighbors = {}
 
-    for i,v in ipairs(relativeNeighbors) do
+    for i,v in ipairs(relative_neighbors) do
         neighbors[i] = pos + v
     end
 

stones.lua

@@ -54,12 +54,18 @@ local function reg(name, basename, basedef)
         },
 
         paramtype = "light",
+
         sunlight_propagates = true,
+
         groups = {
             snappy = 1,
             falling_node = 1,
             falling_repose = 1,
+            go_stone = 1
         },
+
+        go_team = name,
+
         sounds = basedef.sounds,
 
         on_construct = check_captures
@@ -72,7 +78,6 @@ local function reg(name, basename, basedef)
             nodes = {
                     {
                             match = "nc_concrete:" .. name .. "_starcrossy_ply",
-                            --match = {groups = {goban = 1}},
                             replace = "air"
                     }
             },