/fal-gamedev

name: fal-gamedev
description: >
 Generate 2D pixel art game assets, characters, sprite sheets, background
 removal, and game backgrounds. Trigger for "pixel art character", "sprite
 sheet", "walk cycle", "game sprites", "isometric sprites", "side-scroller
 assets", "RPG character sprites", "idle animation", "attack animation",
 "jump animation", "game background", "parallax background", "isometric map",
 "2D game art", "pixel art animation". Covers character generation
 (nano-banana-pro / gpt-image-2), sprite sheet animation (nano/edit or
 gpt-image-2/edit), background removal (Bria), and background generation
 (parallax layers or isometric map).
metadata:
 author: fal-ai-community
 version: "0.1.0"

2D Game Assets

> Requires the [genmedia CLI](https://github.com/fal-ai-community/genmedia-cli) (run `genmedia init` once).

Full pipeline for 2D pixel art game assets: character → sprite sheets → background removal → game background. Each recipe is independently invokable, run just the part you need.

Always use `--json` so output is machine-readable. Use `--download` to save files locally. Do **not** curl URLs manually, use the `--download` flag.

---

Execution rules, follow these strictly

1. **Each genmedia command = one Bash tool call**: issue each `genmedia run` and `genmedia status` as its own bare tool call. No variable assignments, no pipes, no shell redirects. This keeps every call matching the `genmedia *` allowlist so it runs without permission prompts.

2. **Parallel jobs → async**: issue each `genmedia run --async` as its own separate Bash tool call (not combined into one shell block). All jobs queue and run in parallel on fal's side; total time ≈ slowest single job. After all are fired, poll each with `genmedia status` sequentially (not in parallel, one failure must not cancel others).

 # Step 1, fire async (each line = its own Bash tool call, returns request_id immediately)
 genmedia run fal-ai/nano-banana-pro/edit --prompt "$WALK_PROMPT" --image_urls "[\"$CHARACTER_URL\"]" --aspect_ratio "1:1" --resolution "1K" --async --json
 genmedia run fal-ai/nano-banana-pro/edit --prompt "$IDLE_PROMPT" --image_urls "[\"$CHARACTER_URL\"]" --aspect_ratio "1:1" --resolution "1K" --async --json

 # Step 2, poll sequentially (each line = its own Bash tool call)
 genmedia status fal-ai/nano-banana-pro/edit <walk_request_id> --result --download ./walk.png --json
 genmedia status fal-ai/nano-banana-pro/edit <idle_request_id> --result --download ./idle.png --json

3. **URL source**: always read `downloaded_files[0].url` from the tool result JSON. This is the correct path for all models (nano, gpt, Bria).

4. **Bria sync**: Bria (`fal-ai/bria/background/remove`) has no queue endpoint and does not support `--async`. Run it sync. It completes in seconds.

5. **Folder structure**: always save into this layout, deriving the character slug from the character description (kebab-case, e.g. `pirate-carrot`):

 ./game-assets/
 <character-slug>/
 character.png
 sprites/
 walk.png
 idle.png
 attack.png
 jump.png
 backgrounds/
 layer1-sky.png
 layer2-midground.png
 layer3-foreground.png

Create the folders before downloading (`mkdir -p`). Use this structure even for partial runs (e.g. just one sprite sheet still goes in `sprites/`).

6. **End summary**: after all downloads complete, print a summary listing every file path and its CDN URL. Format:

 === Game Assets: pirate-carrot ===
 character game-assets/pirate-carrot/character.png
 https://...
 walk game-assets/pirate-carrot/sprites/walk.png
 https://...

7. **400 on status poll**: `genmedia status --result` fetches the result once; it does not poll automatically. A 400 with `"Request is still in progress"` means the job is still running, wait 10 seconds and retry the exact same `genmedia status` call with the same request_id. Do **not** re-fire the original `genmedia run --async` (the job is already running on fal's side). Keep retrying every 10–15 seconds until you get a successful result.

---

When to use

• Generating a pixel art character from a text description or reference image
• Creating sprite sheet animations (walk, jump, attack, idle) for a side-scroller
• Creating isometric RPG sprite sheets (walk, attack, idle across directions)
• Removing backgrounds from sprite sheets to get transparent PNGs
• Generating parallax backgrounds (3-layer) for side-scrollers
• Generating top-down isometric game maps for RPGs

Models in the stack

• **Nano Banana Pro**: `fal-ai/nano-banana-pro`, character + background generation; better quality and faster, recommended default
• **Nano Banana Pro Edit**: `fal-ai/nano-banana-pro/edit`, sprite sheet generation from character image
• **GPT-Image-2**: `openai/gpt-image-2`, character + background generation; slower than nano, use when user prefers it or wants cheaper output (`quality=low`)
• **GPT-Image-2 Edit**: `openai/gpt-image-2/edit`, sprite sheet generation; slower than nano, requires model-specific walk prompt; use `quality=low` for cheaper runs
• **Bria RMBG 2.0**: `fal-ai/bria/background/remove`, background removal on all sprite sheets

---

Recipe 1. Generate character

Ask the user: character description (text) or an existing image to convert. Ask model preference: `nano` (default, better quality + faster) or `gpt` (slower; use `quality=low` if user wants cheaper output).

CHARACTER_STYLE_PROMPT="Generate a single character only, centered in the frame on a plain white background. The character should be rendered in detailed 32-bit pixel art style (like PlayStation 1 / SNES era games). Include proper shading, highlights, and anti-aliased edges for a polished look. The character should have well-defined features, expressive details, and rich colors. Show in a front-facing or 3/4 view pose, standing idle, suitable for sprite sheet animation."

IMAGE_TO_PIXEL_PROMPT="Transform this character into detailed 32-bit pixel art style (like PlayStation 1 /