# 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/multitile_city_buildings.json` : links the building layers together.

## Making the Roof Map

Refer to [MAPGEN.md](https://github.com/CleverRaven/Cataclysm-DDA/blob/master/doc/JSON/MAPGEN.md) 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

```jsonc
"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-roofs.json and furniture-roof.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:
```jsonc
  {
    "type": "mapgen",
    "om_terrain": "abstorefront_roof",
    "object": {
      "fill_ter": "t_flat_roof",
      "rows": [
        "                        ",
        " -....................- ",
        " -....................- ",
        " -....................- ",
        " -....................- ",
        " -....................- ",
        " -....................- ",
        " -....................- ",
        " -....................- ",
        " -....................- ",
        " -....................- ",
        " -....................- ",
        " -......&.............- ",
        " -....................- ",
        " -.................>..- ",
        " --5------------------- ",
        "                        ",
        "                        ",
        "                        ",
        "                        ",
        "                        ",
        "                        ",
        "                        ",
        "                        "
      ],
      "palettes": [ "roof_palette" ],
      "place_items": [ { "item": "SUS_trash_roof", "x": [ 2, 21 ], "y": [ 3, 14 ], "chance": 50, "repeat": [ 1, 3 ] } ],
      "place_nested": [
        {
          "chunks": [ [ "null", 20 ], [ "roof_4x4_party", 15 ], [ "roof_4x4_holdout", 5 ], [ "roof_4x4_utility", 40 ] ],
          "x": [ 3, 15 ],
          "y": [ 3, 7 ]
        }
      ]
    }
  }
```

## Linking the main floor and the roof
Navigate to `json/overmap/multitile_city_buildings.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.

```jsonc
  {
    "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/overmap_special/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:
```jsonc
  {
    "type": "overmap_special",
    "id": "Evac Shelter",
    "overmaps": [
      { "point": [ 0, 0, 0 ], "overmap": "shelter_north" },
      { "point": [ 0, 0, -1 ], "overmap": "shelter_under_north" },
      { "point": [ 0, 0, 1 ], "overmap": "shelter_roof_north" }
    ],
    "connections": [ { "point": [ 0, -1, 0 ], "terrain": "road", "connection": "local_road", "from": [ 0, 0, 0 ] } ],
    "locations": [ "wilderness" ],
    "city_distance": [ 3, 10 ],
    "city_sizes": [ 4, -1 ],
    "occurrences": [ 0, 2 ],
    "flags": [ "CLASSIC", "URBAN" ]
  }
```
## Adding the overmap_terrain entry

Navigate to `data/json/overmap_terrain/`
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.

```jsonc
  {
    "type": "overmap_terrain",
    "id": [ "abandonedwarehouse", "abandonedwarehouse_1", "abandonedwarehouse_2", "abandonedwarehouse_3", "abandonedwarehouse_4" ],
    "copy-from": "generic_city_building",
    "name": "abandoned warehouse",
    "sym": "w",
    "color": "brown"
  },
  {
    "type": "overmap_terrain",
    "id": [
      "abandonedwarehouse_roof",
      "abandonedwarehouse_1_roof",
      "abandonedwarehouse_2_roof",
      "abandonedwarehouse_3_roof",
      "abandonedwarehouse_4_roof"
    ],
    "copy-from": "generic_city_building",
    "name": "abandoned warehouse roof",
    "sym": "w",
    "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.

```jsonc
"abandonedwarehouse": 200,
```
When testing you can increase the spawn rate if you want to survey your work using natural spawns.

Finally, always [lint](http://dev.narc.ro/cataclysm/format.html) your additions before submitting.
