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aldegad/sprite-gen

Codex/Claude skill and Python CLI that turns one base image into game-ready 2D sprite atlases or transparent animation loops.

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What is it?

sprite-gen addresses a common problem with AI image models: asking for a sprite sheet usually yields a character whose appearance shifts between frames, backgrounds that don't key out cleanly, and PNGs that game engines can't consume directly. The tool starts from a single base image, generates each animation state row by row while keeping the character consistent, removes the chroma-key background into real alpha, and extracts each pose as a transparent frame.

The output is a runtime atlas (sprite-sheet-alpha.png) accompanied by a manifest.json containing absolute frame rectangles, per-state fps and loop flags. Alternatively, the same still image can be passed to a video model to produce a seamless transparent loop per motion state. A curation webview lets users compare, reject, adjust and preview loops before baking the final assets.

The project is organised as several pipelines and utilities: an atlas-row pipeline, a video-to-loop pipeline, utilities for slicing and cutting sheets, post-processing for recoloring and engine exports (Aseprite, Phaser, Flame), independent asset tools such as tiling and shadow projection, and an optional scene composition workflow.

Key features

  • 01Generates sprite states row by row from one base image while keeping the character consistent.
  • 02Converts chroma-key backgrounds into real alpha and extracts clean transparent frames.
  • 03Outputs a runtime atlas with a manifest.json listing frame rectangles, fps and loop flags.
  • 04Produces transparent animation loops from video models, one per motion state.
  • 05Provides a curation webview for reviewing, nudging and previewing frames before baking.
  • 06Includes recoloring and exports to Aseprite JSON for engines like Phaser and Flame.

Use cases

  • Turning a single character illustration into a full set of idle, walk, attack and jump sprites for a 2D game.
  • Generating transparent looping animations from one still image using a video model.
  • Recoloring an existing sprite sheet into multiple palette variants.
  • Exporting sprite atlases to Phaser or Flame via Aseprite JSON.

Quick start

  1. 1

    Create and activate a Python virtual environment

    python3 -m venv .venv && source .venv/bin/activate
  2. 2

    Install sprite-gen in editable mode

    pip install -e .
  3. 3

    Check that the CLI runs

    sprite-gen --help

Things to know

  • Image and video generation need your own Codex or Grok subscription login, or an API key such as XAI_API_KEY.
  • Video loops also require ffmpeg and img2webp installed separately.
  • Walk and run loops are experimental unless motion QA passes, and direction correction is opt-in and can be wrong.

In collections

Claude Code tools, skills & pluginsAI coding assistants & agentsAI image generators & Stable Diffusion toolsGame development tools & engines

Topics

#game-dev#sprite-generation#2d-game#pixel-art#sprite-sheet#ai-tools#image-generation#claude-code#codex#gamedev

FAQ

What is sprite-gen?
Codex/Claude skill and Python CLI that turns one base image into game-ready 2D sprite atlases or transparent animation loops. sprite-gen addresses a common problem with AI image models: asking for a sprite sheet usually yields a character whose appearance shifts between frames, backgrounds that don't key out cleanly, and PNGs that game engines can't consume directly. The tool starts from a single base image, generates each animation state row by row while keeping the character consistent, removes the chroma-key background into real alpha, and extracts each pose as a transparent frame.
Is sprite-gen free to use? What license does it have?
sprite-gen is open source under the Apache-2.0 license. Check the license terms before using it in commercial products.
Is sprite-gen still maintained?
Actively maintained. The last commit to sprite-gen was on Nov 6, 2026.
What can I use sprite-gen for?
Turning a single character illustration into a full set of idle, walk, attack and jump sprites for a 2D game. Generating transparent looping animations from one still image using a video model. Recoloring an existing sprite sheet into multiple palette variants. Exporting sprite atlases to Phaser or Flame via Aseprite JSON.
How do I install sprite-gen?
Create and activate a Python virtual environment: python3 -m venv .venv && source .venv/bin/activate Install sprite-gen in editable mode: pip install -e . Check that the CLI runs: sprite-gen --help
Where can I get sprite-gen?
The source code and installation instructions are on GitHub: https://github.com/aldegad/sprite-gen

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