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osu-lazer/osu.Game/Rulesets/Scoring/HitWindows.cs
2019-12-17 13:00:10 +08:00

228 lines
8.1 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.Diagnostics;
using System.Linq;
using osu.Game.Beatmaps;
using osu.Game.Rulesets.Objects;
namespace osu.Game.Rulesets.Scoring
{
/// <summary>
/// A structure containing timing data for hit window based gameplay.
/// </summary>
public class HitWindows
{
private static readonly DifficultyRange[] base_ranges =
{
new DifficultyRange(HitResult.Perfect, 22.4D, 19.4D, 13.9D),
new DifficultyRange(HitResult.Great, 64, 49, 34),
new DifficultyRange(HitResult.Good, 97, 82, 67),
new DifficultyRange(HitResult.Ok, 127, 112, 97),
new DifficultyRange(HitResult.Meh, 151, 136, 121),
new DifficultyRange(HitResult.Miss, 188, 173, 158),
};
private double perfect;
private double great;
private double good;
private double ok;
private double meh;
private double miss;
/// <summary>
/// An empty <see cref="HitWindows"/> with only <see cref="HitResult.Miss"/> and <see cref="HitResult.Perfect"/>.
/// No time values are provided (meaning instantaneous hit or miss).
/// </summary>
public static HitWindows Empty => new EmptyHitWindows();
public HitWindows()
{
Debug.Assert(GetRanges().Any(r => r.Result == HitResult.Miss), $"{nameof(GetRanges)} should always contain {nameof(HitResult.Miss)}");
Debug.Assert(GetRanges().Any(r => r.Result != HitResult.Miss), $"{nameof(GetRanges)} should always contain at least one result type other than {nameof(HitResult.Miss)}.");
}
/// <summary>
/// Retrieves the <see cref="HitResult"/> with the largest hit window that produces a successful hit.
/// </summary>
/// <returns>The lowest allowed successful <see cref="HitResult"/>.</returns>
protected HitResult LowestSuccessfulHitResult()
{
for (var result = HitResult.Meh; result <= HitResult.Perfect; ++result)
{
if (IsHitResultAllowed(result))
return result;
}
return HitResult.None;
}
/// <summary>
/// Retrieves a mapping of <see cref="HitResult"/>s to their timing windows for all allowed <see cref="HitResult"/>s.
/// </summary>
/// <returns></returns>
public IEnumerable<(HitResult result, double length)> GetAllAvailableWindows()
{
for (var result = HitResult.Meh; result <= HitResult.Perfect; ++result)
{
if (IsHitResultAllowed(result))
yield return (result, WindowFor(result));
}
}
/// <summary>
/// Check whether it is possible to achieve the provided <see cref="HitResult"/>.
/// </summary>
/// <param name="result">The result type to check.</param>
/// <returns>Whether the <see cref="HitResult"/> can be achieved.</returns>
public virtual bool IsHitResultAllowed(HitResult result) => true;
/// <summary>
/// Sets hit windows with values that correspond to a difficulty parameter.
/// </summary>
/// <param name="difficulty">The parameter.</param>
public void SetDifficulty(double difficulty)
{
foreach (var range in GetRanges())
{
var value = BeatmapDifficulty.DifficultyRange(difficulty, (range.Min, range.Average, range.Max));
switch (range.Result)
{
case HitResult.Miss:
miss = value;
break;
case HitResult.Meh:
meh = value;
break;
case HitResult.Ok:
ok = value;
break;
case HitResult.Good:
good = value;
break;
case HitResult.Great:
great = value;
break;
case HitResult.Perfect:
perfect = value;
break;
}
}
}
/// <summary>
/// Retrieves the <see cref="HitResult"/> for a time offset.
/// </summary>
/// <param name="timeOffset">The time offset.</param>
/// <returns>The hit result, or <see cref="HitResult.None"/> if <paramref name="timeOffset"/> doesn't result in a judgement.</returns>
public HitResult ResultFor(double timeOffset)
{
timeOffset = Math.Abs(timeOffset);
for (var result = HitResult.Perfect; result >= HitResult.Miss; --result)
{
if (IsHitResultAllowed(result) && timeOffset <= WindowFor(result))
return result;
}
return HitResult.None;
}
/// <summary>
/// Retrieves the hit window for a <see cref="HitResult"/>.
/// This is the number of +/- milliseconds allowed for the requested result (so the actual hittable range is double this).
/// </summary>
/// <param name="result">The expected <see cref="HitResult"/>.</param>
/// <returns>One half of the hit window for <paramref name="result"/>.</returns>
public double WindowFor(HitResult result)
{
switch (result)
{
case HitResult.Perfect:
return perfect;
case HitResult.Great:
return great;
case HitResult.Good:
return good;
case HitResult.Ok:
return ok;
case HitResult.Meh:
return meh;
case HitResult.Miss:
return miss;
default:
throw new ArgumentException("Unknown enum member", nameof(result));
}
}
/// <summary>
/// Given a time offset, whether the <see cref="HitObject"/> can ever be hit in the future with a non-<see cref="HitResult.Miss"/> result.
/// This happens if <paramref name="timeOffset"/> is less than what is required for <see cref="LowestSuccessfulHitResult"/>.
/// </summary>
/// <param name="timeOffset">The time offset.</param>
/// <returns>Whether the <see cref="HitObject"/> can be hit at any point in the future from this time offset.</returns>
public bool CanBeHit(double timeOffset) => timeOffset <= WindowFor(LowestSuccessfulHitResult());
/// <summary>
/// Retrieve a valid list of <see cref="DifficultyRange"/>s representing hit windows.
/// Defaults are provided but can be overridden to customise for a ruleset.
/// </summary>
protected virtual DifficultyRange[] GetRanges() => base_ranges;
public class EmptyHitWindows : HitWindows
{
private static readonly DifficultyRange[] ranges =
{
new DifficultyRange(HitResult.Perfect, 0, 0, 0),
new DifficultyRange(HitResult.Miss, 0, 0, 0),
};
public override bool IsHitResultAllowed(HitResult result)
{
switch (result)
{
case HitResult.Perfect:
case HitResult.Miss:
return true;
}
return false;
}
protected override DifficultyRange[] GetRanges() => ranges;
}
}
public struct DifficultyRange
{
public readonly HitResult Result;
public double Min;
public double Average;
public double Max;
public DifficultyRange(HitResult result, double min, double average, double max)
{
Result = result;
Min = min;
Average = average;
Max = max;
}
}
}