osu/osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyCalculator.cs

87 lines
3.6 KiB
C#

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.
using System;
using System.Collections.Generic;
using System.Linq;
using osu.Game.Beatmaps;
using osu.Game.Rulesets.Difficulty;
using osu.Game.Rulesets.Difficulty.Preprocessing;
using osu.Game.Rulesets.Difficulty.Skills;
using osu.Game.Rulesets.Mods;
using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
using osu.Game.Rulesets.Osu.Difficulty.Skills;
using osu.Game.Rulesets.Osu.Mods;
using osu.Game.Rulesets.Osu.Objects;
namespace osu.Game.Rulesets.Osu.Difficulty
{
public class OsuDifficultyCalculator : DifficultyCalculator
{
private const double difficulty_multiplier = 0.0675;
public OsuDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
: base(ruleset, beatmap)
{
}
protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
{
if (beatmap.HitObjects.Count == 0)
return new OsuDifficultyAttributes { Mods = mods, Skills = skills };
double aimRating = Math.Sqrt(skills[0].DifficultyValue()) * difficulty_multiplier;
double speedRating = Math.Sqrt(skills[1].DifficultyValue()) * difficulty_multiplier;
double starRating = aimRating + speedRating + Math.Abs(aimRating - speedRating) / 2;
// Todo: These int casts are temporary to achieve 1:1 results with osu!stable, and should be removed in the future
double hitWindowGreat = (int)(beatmap.HitObjects.First().HitWindows.Great / 2) / clockRate;
double preempt = (int)BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.ApproachRate, 1800, 1200, 450) / clockRate;
int maxCombo = beatmap.HitObjects.Count;
// Add the ticks + tail of the slider. 1 is subtracted because the head circle would be counted twice (once for the slider itself in the line above)
maxCombo += beatmap.HitObjects.OfType<Slider>().Sum(s => s.NestedHitObjects.Count - 1);
return new OsuDifficultyAttributes
{
StarRating = starRating,
Mods = mods,
AimStrain = aimRating,
SpeedStrain = speedRating,
ApproachRate = preempt > 1200 ? (1800 - preempt) / 120 : (1200 - preempt) / 150 + 5,
OverallDifficulty = (80 - hitWindowGreat) / 6,
MaxCombo = maxCombo,
Skills = skills
};
}
protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
{
// The first jump is formed by the first two hitobjects of the map.
// If the map has less than two OsuHitObjects, the enumerator will not return anything.
for (int i = 1; i < beatmap.HitObjects.Count; i++)
{
var lastLast = i > 1 ? beatmap.HitObjects[i - 2] : null;
var last = beatmap.HitObjects[i - 1];
var current = beatmap.HitObjects[i];
yield return new OsuDifficultyHitObject(current, lastLast, last, clockRate);
}
}
protected override Skill[] CreateSkills(IBeatmap beatmap) => new Skill[]
{
new Aim(),
new Speed()
};
protected override Mod[] DifficultyAdjustmentMods => new Mod[]
{
new OsuModDoubleTime(),
new OsuModHalfTime(),
new OsuModEasy(),
new OsuModHardRock(),
};
}
}