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# DEMO.md — "Morning Coffee"
The `domain/` folder contains a 5-minute mini-game that exercises every
important `pncdsl` feature in one sitting — without the demo itself
outgrowing the library. The code is a good place to learn from, because
each mechanic appears in **exactly one small file**.
## Story
You've just woken up in your bedroom. The cat (Whiskers) is already
meowing in the kitchen, and you'd better make coffee before she tears
the whole apartment apart.
## Running it
```bash
go run .
```
A window opens at 1280×800 (internal resolution 320×200, 4× scale). No
asset files are needed — every graphic is a colored placeholder /
stylized humanoid until you replace it with real art (see
[`GFX.md`](GFX.md)).
Controls:
- **left click** on a hotspot/UI button: run the active verb
- **left click** on an inventory item: select it (the cursor picks it up)
- **left click** on a hotspot while an item is selected: use-with
- **right click**: deselect the held item, or reset the verb to "Look"
- click during dialog: advance
## Walkthrough (spoilers)
1. **Bedroom** — the `intro` script runs two `Say` lines from the
`player`.
2. Click the **nightstand** with the "Take" verb → you receive `key`.
3. Click the **door** → you switch to the kitchen.
4. **Kitchen** — Whiskers is sitting in the corner. Try "Talk" on her —
a conditional dialog opens; one of the branches is only available
while the cupboard hasn't been opened yet.
5. Click the **shelf** with "Take" → you receive `mug`.
6. Click the **cupboard** with "Use" (key in inventory) → it opens, you
automatically receive `beans`, and the key is consumed. *Or* select
the key in the inventory and click the cupboard — `OnUseWith` does
the same thing.
7. Click the **coffee machine** with `beans` → beans loaded.
8. Click the coffee machine with `mug` → mug in place.
9. Once both flags are set, the coffee machine fires the `victory`
script: two characters talk, a sound plays (stubbed), end card → done.
## Scenes
| ID | Background | Music | Contents |
|------------|------------------|--------------|-----------------------------------------------------------|
| `bedroom` | `bg/bedroom` | `mus/wakeup` | bed, nightstand (key), door |
| `kitchen` | `bg/kitchen` | `mus/calm` | cupboard, shelf, coffee machine, cat (NPC), door |
## Items
| ID | Acquired from | Used for |
|---------|----------------------------------------------|---------------------------------------------------------------------|
| `key` | `bedroom.nightstand` → Take | Use on `kitchen.cupboard`, or as a selected item via `OnUseWith` |
| `beans` | `kitchen.cupboard` (after unlocking) | Selected, used on `kitchen.coffee_machine` |
| `mug` | `kitchen.shelf` → Take | Selected, used on `kitchen.coffee_machine` |
## Characters
- **`player`** — the player character. Walks (`Walk`), talks (`Say`).
Size 28×62 (W×H), roughly the SCUMM-style 30% screen height.
- **`cat`** — Whiskers, the household pet. Present in the kitchen, only
responds to `Talk`, has a dialog tree.
Until you provide real sprites, they're rendered as a stylized humanoid
(skin-tone head + colored torso + dark trousers + feet) and quadruped
(side-view with ears, head, eye, tail) placeholder shape.
## Dialog (`dialog.cat_morning.go`)
```
[start]
cat: Meeeoooow. It's late.
> "Coffee's coming right up." → SetFlag(promised_coffee), end
> "Did you eat the beans?" (only while NOT cupboard_open) → goto beans
> "Leave me alone." → end
[beans]
cat: They're in the cupboard. They're always in the cupboard.
> "Thanks." → end
```
The `Show: p.Not(p.Flag(FlagCupboardOpen))` condition makes the "Did
you eat the beans?" choice disappear once you've opened the cupboard
— this demonstrates conditional choice visibility
(`DialogueChoice.Show`).
## Cutscenes
**`script.intro.go`** — wired up to `OnStart`, runs in the bedroom:
```go
p.Seq(
p.Wait(0.4),
p.Say("player", "Brr, it's cold."),
p.Say("player", "I need coffee before my head explodes."),
p.Walk("player", p.Point{X: 200, Y: 145}),
)
```
**`script.victory.go`** — fired when the coffee machine sees both flags:
```go
p.Seq(
p.Say("player", "All done!"),
p.PlaySound("snd/coffee_done"),
p.Wait(0.6),
p.Say("cat", "Mrrrrow. *content cat noises*"),
p.Say("player", "Morning coffee: saved."),
p.ShowEnd("The End — thanks for playing!"),
)
```
## Flag/var table (`domain.flag.go`)
```go
const (
FlagKeyTaken = "key_taken"
FlagCupboardOpen = "cupboard_open"
FlagMugTaken = "mug_taken"
FlagCoffeeHasBeans = "coffee_has_beans"
FlagCoffeeHasMug = "coffee_has_mug"
FlagPromisedCoffee = "promised_coffee"
)
```
Naming the flags as constants is worth it because the type system then
catches typos — `pncdsl.Flag("cupbord_open")` would otherwise silently
return `false` forever.
## What the demo exercises
| Library feature | Where it shows up |
|------------------------------------|----------------------------------------------------------------|
| `Scene` + `GoTo` | bedroom ↔ kitchen door, with fade transition |
| `Hotspot` with every verb | each scene has multiple hotspots: Look / Use / Talk / Take |
| `Inventory` + `Give` / `TakeAway` | picking up and consuming key, beans, mug |
| `RequireItem` semantics | cupboard checks `HasItem("key")` |
| `OnUseWith` (from the hotspot) | cupboard + key |
| `OnUseWith` (from the item) | coffee machine + beans / mug |
| `Flag` + `If` | cupboard "already open", shelf "already took one" |
| `Dialogue` + `Choice.Show` | cat's dialog tree, vanishing branch driven by a flag |
| `Script` / cutscene | intro (walk+say) + victory (multi-actor, sound, end card) |
| `Walk` with straight-line stepping | every interaction is preceded by a walk target |
| `ShowEnd` | last action of the victory script |
| `Validate()` | `domain/build_test.go` CI-friendly smoke test |
## Files in `domain/`
```
domain/
├── game.go # Build() — calls every define*() in order
├── domain.asset.go # registerAssets(g) — all assets in one place
├── domain.flag.go # flag-name constants
├── character.player.go # definePlayer(g)
├── character.cat.go # defineCat(g)
├── item.key.go # defineKey(g) — OnUseWith: {"cupboard": ...}
├── item.beans.go # defineBeans(g)
├── item.mug.go # defineMug(g)
├── dialog.cat_morning.go # defineCatMorning(g) — 2 nodes, 3+1 choices
├── scene.bedroom.go # defineBedroom(g)
├── scene.kitchen.go # defineKitchen(g)
├── script.intro.go # defineIntroScript(g)
├── script.victory.go # defineVictoryScript(g)
└── build_test.go # Build() + Validate() smoke test
```
Adding a new scene/item: one new file + one line in `Build()` inside
`game.go`. There's no central registry list to edit.
## How to extend it
- **New scene**: create `scene.<name>.go` with a `define<Name>(g *p.Game)`
function that calls `g.SceneManager.Register(...)`. Add a call in
`Build()`. If any hotspot uses `GoTo("<name>")`, `Validate()` will
cross-check the link for you.
- **New item**: same pattern, `item.<name>.go`, register into
`g.ItemManager`. Map keys inside `OnUseWith` must exactly match the
target hotspot's `Name` field.
- **New dialog**: `dialog.<name>.go``DialogueChoice.Show` accepts
anything that implements `Condition` (`Flag`, `HasItem`, `Not(...)`,
etc.).
- **New cutscene**: `script.<name>.go`, register into
`g.ScriptManager`, then fire it anywhere with
`p.RunScript("<name>")`.
## Graphics
The library substitutes a **deterministic colored rectangle** for every
missing image and renders characters as a stylized humanoid/quadruped
shape. The game therefore runs without any asset on disk. When you drop
a generated image into `assets/bg/<name>.png` or
`assets/spr/<name>.png`, the library switches to it immediately — no
code change required.
Prompts and positioning tips for an image AI: [`GFX.md`](GFX.md).
## Back to the library
For the framework structure and the Manager pattern itself, see
[`README.md`](README.md) and [`PLAN.md`](PLAN.md).