chroma_solstice/docs/adding-npcs.md
2026-08-08 00:09:50 -04:00

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# Adding a talkable NPC
An NPC/sign is just an immovable `Entity` that mixes in `Dialogable`. Bumping it
(a rejected move) opens the dialogue box. Talking is the same everywhere — you
only supply **art** + **a story**.
## 1. Write the story
Create `stories/<name>.ink` — a line, a few choices, an ending:
```ink
yo wassup
* kick the sign
it doesnt budge.
* [say nothing] you have nothing to say to a sign.
- -> END
```
## 2. Compile it
The game can't parse `.ink` (LÖVE has no lpeg), so compile to a `.lua` book:
```sh
lua tools/compile_ink.lua <name>
```
Re-run this **every time you edit the `.ink`** — the game loads the `.lua`, not
the `.ink`. (Needs `lua` + `lua-lpeg` installed.)
## 3. Load the book
In `main.lua`, next to `startSignBook`:
```lua
<name>Book = require "stories.<name>"
```
## 4. Make the entity
In `npc.lua`, copy `Sign` — pick your art and name your book:
```lua
Oracle = class("Oracle", Entity)
Oracle:include(Dialogable)
function Oracle:initialize(x, y)
self.book = oracleBook -- from step 3
Entity.initialize(self, {
x = x, y = y, color = "red",
collision = "unmoveable",
sprites = {
red = loadSprite("art/npc/oracle_r.png"),
green = loadSprite("art/npc/oracle_g.png"),
blue = loadSprite("art/npc/oracle_b.png"),
},
})
end
```
Per-channel art lives in `art/npc/` as `<name>_r/_g/_b.png` (16px cells).
## 5. Place it in a room
Map a save class to your entity in `Room:createEntity` (`room.lua`), alongside
the `npc``Sign` branch:
```lua
if class == "oracle" then
local entity = Oracle:new(x, y)
self:registerNpc(entity)
return entity
end
```
Then add it to a room's `rooms/<room>.sav` `objects` list:
```lua
{ class = "oracle", x = 4, y = 8 }
```
That's it — walk into it and it talks. NPCs are stamped into every colour's
collision matrix, so they block movement and obey the world's colour rules (a
red-only player reads them in red).