| name | pocketjs-gba-imagegen |
| description | Generate original GBA-friendly pixel-art asset source sheets through Codex app-server and ImageGen, then save PNGs for PocketJS AOT asset baking. Use when a local coding agent needs reusable tiles, 16x16 character sprites, RPG item icons, or generic Game Boy Advance-style pixel art through the shared Codex image generation path. |
PocketJS GBA ImageGen
Overview
Use this skill when a PocketJS or local Codex agent needs GBA-class pixel-art source images without hand-driving the built-in ImageGen tool. The standard entrypoint is bun imagegen; it starts a temporary Codex app-server on localhost, sends a single ImageGen turn, captures the image_generation result from the app-server event stream, and writes the PNG requested by --out.
The prompt is intentionally generic to the platform category. It must not ask for a specific existing game, franchise, creature, character, logo, or visual style clone.
Standard Workflow
- Confirm the target branch and local changes:
git status --short --branch
- Generate a source sheet with the Bun TypeScript CLI:
bun imagegen --out aot/demo/imagegen/gba-source.png
- Add an art-direction seed only when the user asks for one:
bun imagegen --out aot/demo/imagegen/rainy-port-source.png --theme "rainy port town with stone quays and lanterns"
- Use
--json when another coding agent needs machine-readable output:
bun imagegen --out /tmp/gba-sheet.png --json
- If replacing the AOT demo source sheet, rerun the deterministic extractor:
bun aot/demo/imagegen/build-assets.ts
Prompt Profiles
Use --kind sprite-sheet for the default mixed source sheet: terrain cells plus one generic four-direction walking character.
Use --kind tileset for top-down background terrain and props.
Use --kind character for one 16x16-style walking sprite with down/up/left/right facings and two walk frames per facing.
Use --kind items for small RPG item icons that remain readable as 16x16 sprites.
Constraints
- Keep all command wrappers in Bun TypeScript. Do not add native shell scripts for this workflow.
- Generate original assets only; avoid franchise terms and existing character references.
- Keep the output as a source sheet on a neutral background with gutters so later scripts can crop or quantize it.
- Treat the generated PNG as source art. The AOT runtime still requires deterministic 4bpp extraction before the image can ship as cartridge data.
