walls: add ability to specify group wall_connected for blocks tha…

…t the walls can connect to

game_api.txt

@@ -167,11 +167,11 @@ Doors API
 
 The doors mod allows modders to register custom doors and trapdoors.
 
-`doors.registered_doors[name] = Door definition` 
- * Table of registered doors, indexed by door name 
+`doors.registered_doors[name] = Door definition`
+ * Table of registered doors, indexed by door name
 
-`doors.registered_trapdoors[name] = Trapdoor definition` 
- * Table of registered trap doors, indexed by trap door name 
+`doors.registered_trapdoors[name] = Trapdoor definition`
+ * Table of registered trap doors, indexed by trap door name
 
 `doors.register_door(name, def)`
 
@@ -214,7 +214,7 @@ The doors mod allows modders to register custom doors and trapdoors.
  * `pos` Position of the door
  * `node` Node definition
  * `clicker` Player definition for the player that clicked on the door
- 
+
 ### Door definition
 
 	description = "Door description",
@@ -232,7 +232,7 @@ The doors mod allows modders to register custom doors and trapdoors.
 	gain_open = 0.3, -- optional, defaults to 0.3
 	gain_close = 0.3, -- optional, defaults to 0.3
 	protected = false, -- If true, only placer can open the door (locked for others)
-	on_rightclick = function(pos, node, clicker, itemstack, pointed_thing), 
+	on_rightclick = function(pos, node, clicker, itemstack, pointed_thing),
 	-- optional function containing the on_rightclick callback, defaults to a doors.door_toggle-wrapper
 	use_texture_alpha = "clip",
 
@@ -341,6 +341,11 @@ walls.register(name, desc, texture, mat, sounds)
 ^ mat = "default:stone". Used to auto-generate crafting recipe.
 ^ sounds = sounds: see [#Default sounds]
 
+All walls will be connected to any nodes with one of the following groups:
+ - `wall`
+ - `stone`
+ - `fence`
+ - `wall_connected`
 
 Farming API
 -----------
@@ -1039,7 +1044,7 @@ Trees
 	default.register_sapling_growth(
 		"default:sapling", -- Name of the sapling
 		{
-			can_grow = default.can_grow, -- Function called to determine whether the sapling can grow, should return a boolean 
+			can_grow = default.can_grow, -- Function called to determine whether the sapling can grow, should return a boolean
 			on_grow_failed = default.on_grow_failed, -- Function called when the growth fails
 			grow = function(pos) -- Function called when the growth has success. This should replace the sapling with a tree.
 		}

mods/walls/init.lua

@@ -35,7 +35,7 @@ walls.register = function(wall_name, wall_desc, wall_texture_table, wall_mat, wa
 			connect_back = {-1/4,-1/2,1/4,1/4,1/2 + fence_collision_extra,1/2},
 			connect_right = {1/4,-1/2,-1/4,1/2,1/2 + fence_collision_extra,1/4},
 		},
-		connects_to = { "group:wall", "group:stone", "group:fence" },
+		connects_to = { "group:wall", "group:stone", "group:fence", "group:wall_connected" },
 		paramtype = "light",
 		is_ground_content = false,
 		tiles = wall_texture_table,