MooseTrax Sprite Maker

Green screen in. Sprite sheet out.

MooseTrax Sprite Maker turns a green-screen video or a pile of animation frames into a clean, game-ready sprite sheet. Pick the moment, key out the backdrop, trim and size the frames, then export a sheet PNG, a JSON atlas, a ZIP of frames or an animated GIF.

It runs offline in your browser. Double-click index.html and drop in your clip. No install, no account, no internet. Your files never leave your computer.

How it works

1. Pick the moment. Drag the In and Out handles to the part of the clip you want, preview it with Play range, and grab the frames. Image sequences work too.
2. Remove the backdrop. Press K and click the backdrop (or let the app guess from the corners), then tune Tolerance and Edge softness. Spill cleanup takes the green fringe off edges.
3. Tidy up. Steady trim keeps walk cycles from jittering. Pick a cell size, shave a coloured rim, and press X on frames you don't want.
4. Export. Sheet PNG, sheet + JSON atlas, a ZIP of frames, or a looping GIF.

Your toolkit

• Video or image input: MP4, WebM, and any MOV your browser can play, or a numbered set of PNG / JPG / WebP frames.
• Clip range with In / Out, every-Nth-frame and sample-rate options, and a live keyed preview.
• Chroma key on colour, not brightness, so uneven lighting keys out evenly and whites, greys and skin tones stay solid. Any backdrop colour works.
• Edge cleanup: shave rim and drop stray specks.
• Frame size: Steady, Per-frame or Off trim; fit-content or fixed cells (32–512 px or any size); feet or centre anchor; pixel-art scaling.
• Sheet layout: columns, spacing, border and file name.
• Before / after (hold B), four preview backgrounds, undo / redo and keyboard shortcuts (press ?).

Export for your engine

• Sprite sheet (.png) for any engine that slices a grid.
• Sheet + JSON atlas, hash or array (TexturePacker-style). Loads in Phaser 3 with this.load.atlas, PixiJS, HaxeFlixel and more.
• Sheet + grid info (frameWidth, frameHeight, spacing, columns, fps) for Godot, Unity, GameMaker, Defold, Bevy and others.
• Frames as PNGs (.zip) and an animated GIF for store pages and Discord.
• Special layouts: RPG Maker MZ / MV $ character sheets (12 frames, 3 columns) and Roblox particle flipbooks.

The README has step-by-step settings for each engine.

What's in the zip

• The app (HTML / CSS / JS), README, changelog and license
• A demo character, Pip, as a green-screen video and a frame set, so you can try it right away

System requirements

A current Chrome, Edge, Firefox or Safari on Windows, macOS or Linux. A 1280×720 screen or larger.

License (summary)

• Use everything you export in any project, free or commercial. No royalties, no credit needed.
• One purchase covers you and your team.
• Please don't resell or redistribute the tool itself. See LICENSE-COMMERCIAL.txt.

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Questions or found a bug? Leave a comment below. — Johnny, MooseTrax Gaming Studio