mania-judge

Work in progress.

Simulates osu!stable mania judgements.

Status

• Implemented: judgements, combo, and life.
• Not implemented: score.
• Tap-only: accurate in current tests.
• Hold: not expected to be exact yet because the precise stable hold algorithm is still unknown.
• Mod coverage: HT, DT, HR, EZ, and MR.
• Not supported: RD.

Usage

Core simulation

import { v1, calcAccuracy } from 'mania-judge'

const judgements = v1.playOsu(osuData)
const frames = v1.generateFramesOsu(judgements, osuData.hp)
const lastFrame = frames.at(-1)

if (lastFrame) {
  const accuracy = calcAccuracy(lastFrame.resultCounts, v1.accTable)
  console.log(lastFrame.resultCounts, lastFrame.maxCombo, lastFrame.life, accuracy)
}

Parsing .osu / .osr files

Use osu-mania-io to parse beatmap and replay files, then convert the result with the adapter functions in column.ts:

import { parseBeatmap } from 'osu-mania-io/beatmap'
import { parseReplay } from 'osu-mania-io/replay'
import { applyLegacyBeatmapMods } from 'osu-mania-io/mod'
import { beatmapToNoteColumns, replayToActionColumns } from 'mania-judge'

const beatmap = parseBeatmap(osuContent)
const replay = parseReplay(osrBuffer, beatmap.difficulty.keyCount)

// Apply mods if needed.
const effective = replay.mods !== 0
  ? applyLegacyBeatmapMods(beatmap, replay.mods)
  : beatmap

const osuData = {
  od: effective.difficulty.overallDifficulty,
  hp: effective.difficulty.hpDrainRate,
  speedRate: 'speedMultiplier' in effective ? effective.speedMultiplier : 1,
  windowScale: 'hitWindowScale' in effective ? effective.hitWindowScale : 1,
  noteColumns: beatmapToNoteColumns(effective),
  actionColumns: replayToActionColumns(replay.frames, beatmap.difficulty.keyCount),
}