feat(content): add constructing niter beds to obtain saltpeter (#5446)

* feat(content): add constructing niter beds to obtain saltpeter

* Update external_tileset.md

data/json/construction.json

@@ -123,6 +123,26 @@
     "pre_terrain": "t_clay_bog",
     "post_terrain": "t_dirt"
   },
+  {
+    "type": "construction",
+    "id": "constr_niter_bed",
+    "group": "build_niter_bed",
+    "category": "OTHER",
+    "required_skills": [ [ "survival", 4 ], [ "cooking", 4 ] ],
+    "time": "10 m",
+    "components": [
+      [ [ "material_soil", 20 ] ],
+      [ [ "straw_pile", 20 ], [ "withered", 20 ], [ "pine_bough", 20 ] ],
+      [ [ "material_soil", 20 ] ],
+      [ [ "material_sand", 200 ], [ "pebble", 40 ] ],
+      [ [ "water", 20 ], [ "water_clean", 20 ] ],
+      [ [ "fertilizer_liquid", 20 ], [ "fertilizer_commercial", 4 ] ]
+    ],
+    "pre_note": "Will be harvestable after one season.",
+    "pre_terrain": "t_pit_shallow",
+    "post_terrain": "t_niter_bed_fresh",
+    "dark_craftable": true
+  },
   {
     "type": "construction",
     "id": "constr_improvised_shelter",

data/json/construction_group.json

@@ -844,6 +844,11 @@
     "id": "gather_clay_from_dirt",
     "name": "Gather Clay From Dirt"
   },
+  {
+    "type": "construction_group",
+    "id": "build_niter_bed",
+    "name": "Build Niter Bed"
+  },
   {
     "type": "construction_group",
     "id": "clean_broken_window",

data/json/external_tileset/External_Tileset_DP_terrain_normal.json

@@ -19,7 +19,9 @@
               { "id": "end_piece", "fg": [ 10, 11, 6, 7 ] },
               { "id": "unconnected", "fg": 16 }
             ]
-          }
+          },
+          { "id": "t_niter_bed_fresh", "fg": 17 },
+          { "id": "t_niter_bed_ready", "fg": 18 }
         ],
         "sprite_width": 32,
         "sprite_height": 32

data/json/furniture_and_terrain/terrain-manufactured.json

@@ -1495,5 +1495,45 @@
       "items": [ { "item": "pointy_stick", "count": 4 }, { "item": "string_6", "count": 4 }, { "item": "tarp", "count": 1 } ]
     },
     "flags": [ "TRANSPARENT", "FLAMMABLE", "THIN_OBSTACLE", "INDOORS", "MOUNTABLE", "EASY_DECONSTRUCT" ]
+  },
+  {
+    "type": "terrain",
+    "id": "t_niter_bed_fresh",
+    "name": "unfinished niter bed",
+    "description": "A wet heap of fertilizer and plant matter covered in soil for traditional saltpeter production.  In about a season, enough potassium nitrate will leach through and crystallize to be harvestable.",
+    "symbol": "#",
+    "color": "brown",
+    "looks_like": "t_claymound",
+    "move_cost": 5,
+    "transforms_into": "t_niter_bed_ready",
+    "flags": [ "TRANSPARENT", "DIGGABLE", "HARVESTED" ],
+    "bash": {
+      "sound": "thump!",
+      "sound_fail": "thump!",
+      "str_min": 50,
+      "str_max": 100,
+      "ter_set": "t_dirt",
+      "items": [ { "item": "material_soil", "count": [ 5, 15 ] } ]
+    }
+  },
+  {
+    "type": "terrain",
+    "id": "t_niter_bed_ready",
+    "name": "mature niter bed",
+    "description": "This heap of nitrated compost has leached out and crystallized a bunch of niter.  Dig here to extract it.",
+    "symbol": "#",
+    "color": "brown",
+    "looks_like": "t_claymound",
+    "move_cost": 5,
+    "flags": [ "TRANSPARENT", "DIGGABLE" ],
+    "digging_result": "digging_niter_bed",
+    "bash": {
+      "sound": "thump!",
+      "sound_fail": "thump!",
+      "str_min": 50,
+      "str_max": 100,
+      "ter_set": "t_dirt",
+      "items": [ { "item": "material_soil", "count": [ 5, 15 ] }, { "item": "material_niter", "count": [ 0, 1 ] } ]
+    }
   }
 ]

data/json/itemgroups/misc.json

@@ -153,6 +153,13 @@
       { "item": "gold_small", "count": [ 400, 1600 ], "prob": 5 }
     ]
   },
+  {
+    "id": "digging_niter_bed",
+    "type": "item_group",
+    "subtype": "collection",
+    "//": "Results of standard digging, plus niter.",
+    "items": [ { "group": "digging_soil_loam_200L" }, { "item": "material_niter" } ]
+  },
   {
     "id": "office_paper",
     "type": "item_group",

doc/src/content/docs/en/mod/json/reference/graphics/external_tileset.md

@@ -49,6 +49,8 @@ Links to relevant pull requests, for content covered below:
 - Makeshift cannons and canister shot:
   [#5398](https://github.com/cataclysmbnteam/Cataclysm-BN/pull/5398)
 
+- Niter beds: [#5446](https://github.com/cataclysmbnteam/Cataclysm-BN/pull/5446)
+
 ## Undead People
 
 The following is a current list of sprites this folder adds to the UDP tileset, in which files and
@@ -95,6 +97,11 @@ Ultica are planned for the future.
 - Makeshift cannon, item and vehiclepart sprite. Item specific to BN.
 - Explosive cannonshells and sprites for readied cannon ammo. Items specific to BN.
 
+### External_Tileset_DP_terrain_normal.png
+
+- Rice paddies. Terrain specific to BN.
+- Niter beds. Terrain specific to BN.
+
 ### External_Tileset_DP_Tall.png
 
 - Off state for utility light. Ability to switch on and off specific to BN.