Map Generator (Grid Level Editor)

Map Generator is a manual, tile-by-tile grid painter for building ASCII level layouts that GridLevelBuilder can turn into real 3D geometry. Despite the name, it doesn't generate anything procedurally — think of it as a spreadsheet-like paint tool for level data, not a random-dungeon generator.

Enabling it

Set enableInspector: true on your SmallWorld config and Map Generator opens as one of the docked Forge windows:

import { SmallWorld } from "small-world";

class MyGame extends SmallWorld {
  constructor() {
    super({ enableInspector: true });
  }
}

Press Ctrl+Alt+G (or Cmd+Alt+G) to show/hide the Forge overlay.

Standalone page

Map Generator is also available at /tools/map-gen.html as a self-contained page — it's the same class, just mounted directly into the page instead of a Forge window. It preloads a small demo room instead of reading from localStorage.

Painting a map

The grid starts at 40×25 cells. Click a swatch in the palette to select a tile type, then click-drag on the canvas to paint:

Char	Tile	Char	Tile
W	Wall	I	Item
G	Wall 2	l	Torch
+	Door	T	Lava
O	Secret	~	Slime
P	Player	.	Empty
E	Enemy
b	Barrel

Other controls:

• Resize — set new W/H values and click Resize; existing content is preserved (anchored top-left), new area is padded with Empty.
• Bucket Fill (Empty) — despite the name, this isn't a flood fill from a click point. It replaces every Empty (.) cell on the whole grid with whichever tile is currently selected — useful for laying a base floor before detailing.
• Clear Map — resets every cell to Empty (asks for confirmation first).
• Export String / Import String — round-trips the map through the text area as a plain newline-separated grid of characters, one per cell.

There are no keyboard shortcuts — painting is entirely mouse-driven — and no undo/redo.

Exporting to a game

Click ▶ Play in YAD to save the current map to localStorage (key yad_custom_map) and open the YAD showcase in a new tab, which reads that key on startup and uses it instead of its bundled default level. This is the only code path that writes that key; Map Generator and YAD only ever read it back.

Map Generator's palette and YAD's legend don't fully agree

YAD's actual level legend uses 1/2/3 for health/armor/weapon items — it never reads I. And while YAD configures lavaFloorChars: ["T"], its legend has no T entry, so a T tile painted here currently falls through to plain floor in YAD rather than rendering as lava. If you're building levels for YAD specifically, treat the editor's palette as a starting point, not a guaranteed 1:1 mapping — check YAD's legend in src/apps/yad/App.ts's setupScene() for what actually renders.

Using the exported string yourself

The export format is deliberately generic — it's just rows of characters, one per grid cell — and consumed by GridLevelBuilder.build(scene, mapString, config), which you configure with your own legend: Record<char, GridLegendEntry> mapping each character to a "block", "floor", "sprite", or "custom" tile definition. Map Generator doesn't know anything about your game's specific tile semantics — that mapping is entirely up to you when you call GridLevelBuilder yourself. See YAD's YadLevelBuilder for a worked example of layering game-specific meaning (AI-enabled enemies, animated doors, bobbing item pickups) on top of the base grid builder.

Limitations

• No procedural generation — it's a manual painter, despite the class name.
• "Bucket Fill" is a whole-grid replace, not a flood fill from the clicked cell.
• No undo/redo, no keyboard shortcuts, no multi-cell selection or line/rectangle tools.
• Import/export asymmetry: importing trims whitespace from both ends of every line, while GridLevelBuilder only trims trailing whitespace — leading-space "indentation" tricks the builder supports won't survive a round-trip through Import String.
• No size limits or validation on the resize inputs — entering a very large width/height can hang the browser building the canvas.
• Map data isn't versioned in localStorage — once you've played a custom map in YAD, it stays the active level indefinitely (overriding the bundled level) until it's cleared manually.