Adding Json Roof Guide

Adding json roofs to a building involves using a few more files to link the roof and building together during mapgen.

Files that will be edited:

data/json/mapgen/[name of building].json : the map of the building and roof.

data/json/overmap_terrain.json : defines the building’s overmap characteristics.

data/json/regional_map_settings.json : defines the building’s overmap spawn settings.

data/json/overmap/multietile_city_buildings.json : links the building layers together.

Making the Roof Map

Refer to MAPGEN for creating the map if you are new to map creation.

Open the file that contains the map for the building data/json/mapgen/[name of building].json Add a new entry for the roof. You can copy the building entry since you want the same foundation footprint for the roof.

Give the roof a unique om_terrain ID. Below is an example of the main floor and roof om_terrain IDs

"om_terrain": [ "abstorefront" ],
"om_terrain": [ "abstorefront_roof" ],

Note: If you are adding a roof to an existing building that shares a common om_terrain ID with other maps, you will need to change the om_terrain ID for the existing floor to be unique.

Keep the outline of the walls from the original floor, Add t_open_air outside the building and a t_flat_roof over the building’s footprint. There are a few flat roof terrains to choose from in terrain.json.

There are a number of terrains and furniture structures for roofs including gutters, chimneys, and roof turbine vents. Browse json/terrain.json and furniture.json for ideas. Consider roof access, you can use ladders, stairs and gutters. Some furniture is also climbable.

There is a set of optional nested map chunks at data/json/mapgen/nested_chunks_roof.json if you’d like to incorporate them. Add any new nested chunks for roofs here as well.

Sample roof entry:

{
  "type": "mapgen",
  "method": "json",
  "om_terrain": "abstorefront_roof",
  "weight": 200,
  "object": {
    "fill_ter": "t_flat_roof",
    "rows": [
      "                        ",
      " |....................3 ",
      " |....................3 ",
      " |....................3 ",
      " |....................3 ",
      " |....................3 ",
      " |....................3 ",
      " |....................3 ",
      " |....................3 ",
      " |....................3 ",
      " |....................3 ",
      " |....................3 ",
      " |......&.............3 ",
      " |....................3 ",
      " |....................3 ",
      " |-----------------5--3 ",
      "                        ",
      "                        ",
      "                        ",
      "                        ",
      "                        ",
      "                        ",
      "                        ",
      "                        "
    ],
    "terrain": {
      ".": "t_flat_roof",
      " ": "t_open_air",
      "|": "t_gutter_west",
      "-": "t_gutter_south",
      "3": "t_gutter_east",
      "5": "t_gutter_drop"
    },
    "furniture": { "&": "f_roof_turbine_vent" },
    "place_items": [
      { "item": "roof_trash", "x": [2, 21], "y": [3, 14], "chance": 50, "repeat": [1, 3] }
    ],
    "place_nested": [
      {
        "chunks": [
          ["null", 50],
          ["roof_4x4_party", 15],
          ["roof_4x4_holdout", 5],
          ["roof_4x4_utility", 40],
          ["roof_5x5_coop", 5]
        ],
        "x": [3, 15],
        "y": [3, 7]
      }
    ]
  }
}

Linking the main floor and the roof

Navigate to json/overmap/multitile_city_buildings.json or json/overmap/multitile_buildings_terrain.json for buildings taking up more then one overmap tile per z level (schools, mansions). Add an entry for the main floor. The point coordinates define to the x, y, z positions of the building. The 1 places the roof one z level above the ground floor. Append north for rotating buildings to orient the z levels.

{
  "type": "city_building",
  "id": "abstorefront",
  "locations": ["land"],
  "overmaps": [
    { "point": [0, 0, 0], "overmap": "abstorefront_north" },
    { "point": [0, 0, 1], "overmap": "abstorefront_roof_north" }
  ]
}

Overmap Specials

Overmap specials are handled a little differently. They use json/overmap/specials.json for both linking z levels and overmap spawning. A special won’t need an entry in data/json/regional_map_settings.json

Overmap special example:

{
  "type": "overmap_special",
  "id": "Evac Shelter",
  "overmaps": [
    { "point": [0, 0, 0], "overmap": "shelter" },
    { "point": [0, 0, -1], "overmap": "shelter_under" },
    { "point": [0, 0, 1], "overmap": "shelter_roof" }
  ],
  "connections": [
    { "point": [0, -1, 0], "terrain": "road" }
  ],
  "locations": ["wilderness"],
  "city_distance": [5, 10],
  "city_sizes": [4, 12],
  "occurrences": [1, 3],
  "rotate": false,
  "flags": ["CLASSIC"]
}

Adding the overmap_terrain entry

Navigate to data/json/overmap_terrain.json Every z level gets an entry that defines how it appears on the overmap. The name field will determine what is displayed in the in-game overmap. The entries should share the same color and symbol.

  {
    "type": "overmap_terrain",
    "id": "abandonedwarehouse",
    "copy-from": "generic_city_building",
    "name": "abandoned warehouse",
    "sym": 119,
    "color": "brown"
  },
  {
    "type": "overmap_terrain",
    "id": "abandonedwarehouse_roof",
    "copy-from": "generic_city_building",
    "name": "abandoned warehouse roof",
    "sym": 119,
    "color": "brown"
}

Adding to regional_map_settings

Navigate to data/json/regional_map_settings.json

This determines the spawn frequency and location of non-special buildings. Find the appropriate category for your building and add either the overmap_special ID or the city_building ID and include a spawn weight.

"abandonedwarehouse": 200,

When testing you can increase the spawn rate if you want to survey your work using natural spawns.

Finally, always lint your additions before submitting.