Terrain#

This page shows how to give cells their behaviour: what blocks walking or sight, what a door does, what a trap does, and how a spell reacts to what it hits.

What a cell contains#

A cell holds, in this order: the player, creatures, floor hazards, spell fields, traps, then the terrain itself. Every occupant behaves through its components: small named behaviours such as blocksMovement or flammable. A component describes what something does, never what it is called. A web is flammable; it is not "a web that burns".

Terrain components live in public/config/world.json, under terrain. Every terrain must list its components. An empty list is open, see-through floor. Creature families take theirs from creatures.json, and hazards from the hazards section of creature-rules.json.

Components#

Water declares only blocksMovement: you cannot cross it, but you can see the far bank. Walls add blocksSight.

Goal: a floor type that slows creatures and burns away.

[{ "component": "flammable" }, { "component": "slowsMovement", "cost": 2 }]

Hazards are declared the same way. A frost hazard freezes whoever stays on its cell:

{ "components": [{ "component": "onStay", "actions": [{ "kind": "status", "status": "frozen", "turns": 2 }] }] }

Doors#

A closed door blocks movement and sight, muffles sound, and has an interact component that opens it into another terrain.

Goal: a closed door that the player opens from the next cell.

[{ "component": "blocksMovement" }, { "component": "blocksSight" }, { "component": "interact", "reach": "adjacent", "actions": [{ "kind": "operateDoor", "operation": "open", "tile": "doorOpen" }] }]

• tile must exist in the terrain list and differ from the door itself.
• reach: "adjacent" means the door is on a neighbouring cell. The default, self, targets the cell under the player.
• A locked door uses forceDoor instead. It also needs a doorForcing block in world.json.

The game places doors when it generates floors. This extract from world.json sets a 25% chance on the first floor, growing by 2.5% per floor:

{ "doorGeneration": { "tile": "door" }, "balance": { "doorChance": 0.25, "doorGrowth": 0.025 } }

Doors only go on narrow room thresholds, and every room keeps at least one free entrance. Add lockedTile and lockedDoorChance to turn some of them into locked doors.

Devices#

A device is something the player places, such as a trap. Devices are declared in devices.json. A device sets its glyph, its trigger and its components. The trigger is enter, turn or adjacent.

Goal: a proximity mine that slows anyone next to it for three turns.

{
  "proximity": {
    "name": "TACTICS_SYSTEM_TRAP",
    "glyph": "^", "color": "#90e9ec",
    "trigger": "adjacent", "charges": 3, "turns": 3,
    "components": [{"component": "onStay", "actions": [
      {"kind": "status", "status": "slowed", "turns": 3}
    ]}]
  }
}

• The player's own devices hit the player too.
• enter reads onEnter; turn and adjacent read onStay.
• allowedTerrain limits where it can be placed.

Interactions with spells#

An interaction says what happens when a spell of some element touches an occupant that has a component. Interactions live in magic.json, under magic.interactions.

Goal: fire destroys anything flammable.

{ "effect": { "element": "fire" }, "component": "flammable", "actions": [{ "kind": "destroy" }] }

See Magic for elements.

Named fields#

A named field is a lasting zone that a spell leaves behind. Declare it in magic.json under magic.namedFields, then reference it from the field action.

{
  "opaque-air": {
    "name": "MAGIC_SYSTEM_AIR", "glyph": "◇", "color": "#a9baaf",
    "power": 0, "elements": [],
    "components": [{ "component": "blocksSight" }]
  }
}

Fields accept blocksMovement, blocksSight, dampensSound, flammable, slowsMovement, consumedOnTrigger, onEnter and onStay. They refuse interact and regenerates.

If the game refuses your cells at startup, see Troubleshooting.

• Magic

  Elements and spells.

• Creatures

  Hearing and creature components.