DDRCompanion/lib/stepcharts/util.ts

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2024-05-15 17:57:16 +00:00
import Fraction from "fraction.js";
const beats = [
new Fraction(1).div(4),
new Fraction(1).div(6),
new Fraction(1).div(8),
new Fraction(1).div(12),
new Fraction(1).div(16),
];
function determineBeat(offset: Fraction): Arrow["beat"] {
const match = beats.find((b) => offset.mod(b).n === 0);
if (!match) {
// didn't find anything? then it's a weirdo like a 5th note or 32nd note, they get colored
// the same as 6ths
return 6;
}
return match.d as Arrow["beat"];
}
const normalizedDifficultyMap: Record<string, Difficulty> = {
beginner: "beginner",
easy: "basic",
basic: "basic",
trick: "difficult",
another: "difficult",
medium: "difficult",
difficult: "expert",
expert: "expert",
maniac: "expert",
ssr: "expert",
hard: "expert",
challenge: "challenge",
smaniac: "challenge",
// TODO: filter edits out altogether
edit: "edit",
};
function similarBpm(a: Bpm, b: Bpm): boolean {
return Math.abs(a.bpm - b.bpm) < 1;
}
function mergeSimilarBpmRanges(bpm: Bpm[]): Bpm[] {
return bpm.reduce<Bpm[]>((building, b, i, a) => {
const prev = a[i - 1];
const next = a[i + 1];
if (prev && similarBpm(prev, b)) {
// this bpm was merged on the last iteration, so skip it
return building;
}
if (next && similarBpm(next, b)) {
return building.concat({
...b,
endOffset: next.endOffset,
});
}
return building.concat(b);
}, []);
}
export { determineBeat, normalizedDifficultyMap, mergeSimilarBpmRanges };