I needed new assets for Medieval Boom. I cannot draw. Apparently my solution to a missing skill is another repository.
SpriteSheetStudio is a local web app for turning generated or uploaded sprites into animations. Generate movement video, extract transparent frames, pick a sequence, set its speed, and export a PNG spritesheet. It has already produced the mage, knight, and ranger skins for Boom, which is more useful than most of my side projects can claim.
It started as a fork of acatovic/ai-game-studio. The original flow didn’t quite fit how I work, so I reshaped it around projects that can hold multiple named animations. An idle, a run, and an attack can live together; generating another movement video doesn’t wipe the animations I’ve already saved.
Boom also uses runtime team-color palette swaps, so “roughly the right blue” doesn’t cut it. I added shared color palettes to constrain reference sprite colors, plus frame palette locking to keep animations tied to the reference sprite’s colors. The runtime still handles the team swaps; this tool helps prepare the source art.
This is a personal tool with manual frame selection and results that still need inspecting. It runs locally, uses OpenRouter for generation, and processes frames locally with ffmpeg and Sharp. Setup instructions are in the README.
Tech Stack
- Vue + TypeScript + Vite — the studio interface
- Express — local backend and project storage
- OpenRouter — image and video generation
- ffmpeg + Sharp — frame extraction and image processing