oszillator

An unofficial osu!standard-style player experiment for the browser.

oszillator started from a simple idea: what if osu!standard could run in a web page, just because it would be fun? Drop a beatmap archive into the browser, pick a difficulty, and click circles. The app parses the map locally, keeps the Web Audio clock as the gameplay timeline, renders the playfield with Pixi, and keeps scores on your machine only.

Online Demo

Try the hosted demo here: https://n0zom1z0.github.io/oszillator/

The demo is a static GitHub Pages build of the same browser player. Import a .osz archive from your own machine and the beatmap, background, video, and audio are processed in your browser; the app does not upload beatmap files or submit scores to a server. The page also includes a small showcase so the first screen is not empty before you import your own archive.

Watch the autoplay demo on YouTube: https://www.youtube.com/watch?v=0RBsNySsgOs

Highlights

• Drag-and-drop .osz import with no account, server sync, or online beatmap download.
• osu!standard-focused gameplay with circles, sliders, spinners, hit judgements, combo, accuracy, and local scores.
• Web Audio based timing so judgement uses the audio clock rather than frame deltas.
• Autoplay showcase mode for hands-free previews and visual demos.
• osu!-style modifiers: Hidden, HardRock, Double Time, and Nightcore.
• Beatmap background image and browser-supported video playback from the imported archive.
• Dynamic cursor trail, spinner effects, smoke key, hit offset history, and optional dynamic colour cycling.
• Parser and loader designed to warn and continue when real-world .osu files contain unknown fields.

Controls

• Z / X: keyboard hit buttons.
• Mouse / pointer: aim and click.
• C: smoke trail.
• Autoplay: let oszillator perform an idealized replay.
• Dynamic colours: opt into animated palette cycling for cursor and objects.

Product Boundaries

• Unofficial osu!standard-style browser experiment.
• osu!standard-style gameplay only.
• Local archive import only.
• No ranking, leaderboard, login, server sync, or online score submission.
• No online beatmap search or download.
• No official branding or bundled official assets.
• No copyrighted beatmap, audio, or video fixtures are committed to this repository.

Development

corepack pnpm install
corepack pnpm dev
corepack pnpm typecheck
corepack pnpm test
corepack pnpm build
corepack pnpm test:e2e

Workspace

• apps/player: Vite browser app and UI orchestration.
• packages/audio-engine: Web Audio clock, playback, offsets, and hitsounds.
• packages/core: shared math, time, playfield transforms, search, and input primitives.
• packages/osu-parser: warning-first .osu parser.
• packages/osz-loader: .osz unzip and manifest generation.
• packages/renderer-pixi: Pixi gameplay renderer.
• packages/ruleset-std: osu!standard preparation, modifiers, judgement, and scoring.
• packages/slider-geometry: deterministic slider path helpers.
• packages/storage: local metadata, settings, and scores.

Media

The repository includes a lightweight demo poster in docs/assets/demo-poster.jpg. Keep full recordings outside the git history unless there is a strong reason to version them. See docs/media.md for the recommended README video workflow.