implement tunnels

bin/config/buildings.toml

@@ -12,6 +12,21 @@ player_placeable = true
 construction_time_seconds = 1
 surface_mask = ["<A>"]
 
+[[building]]
+id = "tunnel_entry"
+cost = 5
+player_placeable = true
+construction_time_seconds = 3
+surface_mask = ["A>"]
+tunnel_max_distance = 10
+
+[[building]]
+id = "tunnel_exit"
+cost = 5
+player_placeable = true
+construction_time_seconds = 3
+surface_mask = ["A>"]
+
 [[building]]
 id = "miner"
 cost = 15

bin/config/visuals.toml

@@ -72,6 +72,16 @@ fill    = "#7a7a5a"
 outline = "#9a9a7a"
 glyph   = ""
 
+[buildings.tunnel_entry]
+fill    = "#4a6a5a"
+outline = "#8aaa9a"
+glyph   = "Te"
+
+[buildings.tunnel_exit]
+fill    = "#5a6a4a"
+outline = "#9aaa8a"
+glyph   = "Tx"
+
 # -----------------------------------------------------------------------------
 # Stations
 #